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Species identification after treatment for taeniasis
Abstract
Identification of species of human tapeworms is crucial because the consequences of infection by Taenia solium and T saginata are very different. However, evacuation of species-identifiable tapeworms is uncommon and Taenia spp eggs are indistinguishable under the microscope. Treatment of taeniasis consists of niclosamide followed by a purgative. Recently, we adopted preniclosamide and postniclosamide electrolyte-polyethyleneglycol salt (EPS) purges to improve bowel cleaning. Retrospective comparison of traditional castor oil with EPS purge showed that recovery of the tapeworm scolex was significantly improved (20 of 68 vs none of 46, p=0.0001) in the EPS group. Furthermore, 42 of 68 (62%) individuals receiving EPS excreted identifiable gravid proglottids. EPS treatment helps the visual identification of Taenia spp.
... This recovery has, however, proven difficult due to the disintegration of the proximal end of the worm when modern cestocidal drugs are used (WHO, 1983). Jeri et al., (2004) improved the treatment method to obtain a recognizable tapeworm by using preniclosamide and post-niclosamide electrolyte-polyethyleneglycol (PEG) salt purges to improve bowel cleaning and collection of the tapeworm scolex, making differentiation between T. saginata and T. solium easier. Nevertheless, since PEG has to be dissolved in two liters of water, it is very difficult to be accepted, especially in community studies. ...
... Only one tapeworm (from a participant positive on both copro-Ag and coproscopic examination) could be recovered after treatment of the 45 copro-Ag positive participants. The low recovery rate of tapeworms can be explained by: (1) stools were obtained only over one day and not over 3 days post treatment (Jeri et al., 2004) due to logistical constraints, (2) usually after antiparasitic treatment, small and unrecognizable fragments are expelled by most patients (Jeri et al., 2004) and these are easily missed, and (3) treatment of copro-Ag positive individuals was conducted over six months after collection of stool samples; natural expulsion may have occurred in this period, especially if it is during harvest when pumpkin seeds are eaten and they promote tapeworm release. ...
... Only one tapeworm (from a participant positive on both copro-Ag and coproscopic examination) could be recovered after treatment of the 45 copro-Ag positive participants. The low recovery rate of tapeworms can be explained by: (1) stools were obtained only over one day and not over 3 days post treatment (Jeri et al., 2004) due to logistical constraints, (2) usually after antiparasitic treatment, small and unrecognizable fragments are expelled by most patients (Jeri et al., 2004) and these are easily missed, and (3) treatment of copro-Ag positive individuals was conducted over six months after collection of stool samples; natural expulsion may have occurred in this period, especially if it is during harvest when pumpkin seeds are eaten and they promote tapeworm release. ...
The thesis provides an understanding of the epidemiology of human Taenia sloium infections in the Eastern province of Zambia
... Differentiation of T. solium and T. saginata is based on the morphological characteristics of the scolex or gravid proglottids (21). Recovery of scolices after treatment is unusual for T. solium, and in many cases, both the scolex and proglottids can be recovered only after special treatment (18). ...
... Positive stool samples. All known positive samples were obtained from previous field studies (18). Taeniasis-positive patients identified upon microscopic examination were given standard medical treatment as indicated (18). ...
... All known positive samples were obtained from previous field studies (18). Taeniasis-positive patients identified upon microscopic examination were given standard medical treatment as indicated (18). Informed consent was approved by the ethical committee of the Johns Hopkins School of Public Health and the Universidad Peruana Cayetano Heredia. ...
Taeniasis due to Taenia solium is a disease with important public health consequences, since the larval stage is not exclusive to the animal intermediate, the pig, but also infects humans, causing neurocysticercosis. Early diagnosis and treatment of T. solium tapeworm carriers is important to prevent human cysticercosis. Current diagnosis based on microscopic observation of eggs lacks both sensitivity and specificity. In the present study, a nested-PCR assay targeting the Tso31 gene was developed for the specific diagnosis of taeniasis due to T. solium. Initial specificity and sensitivity testing was performed using stored known T. solium-positive and -negative samples. The assay was further analyzed under field conditions by conducting a case-control study of pretreatment stool samples collected from a population in an area of endemicity. Using the archived samples, the assay showed 97% (31/32) sensitivity and 100% (123/123) specificity. Under field conditions, the assay had 100% sensitivity and specificity using microscopy/enzyme-linked immunosorbent assay coproantigen testing as the gold standards. The Tso31 nested PCR described here might be a useful tool for the early diagnosis and prevention of taeniasis/cysticercosis.
... Biosafety measures for health personnel, for the patient and the environment must be taken into consideration given the fact that manipulation of feces infected with T. solium may result in cysticercosis or neurocysticercosis. This process must be conducted under medical supervision to prevent or manage adverse effects of the purge or medication, and to avoid contamination by contact with infective eggs in feces (31) . ...
... Once liquid feces are obtained, the appropriate dose of niclosamide must be given (2 gr orally for adults, 1 gr for children older than 6). Two hours after niclosamide intake, a second purge is administered (30,31) . The whole process must involve abundant oral hydration to avoid dehydration or electrolyte disorders, and to facilitate purge and elimination of the worm. ...
... Biosafety measures for health personnel, for the patient and the environment must be taken into consideration given the fact that manipulation of feces infected with T. solium may result in cysticercosis or neurocysticercosis. This process must be conducted under medical supervision to prevent or manage adverse effects of the purge or medication, and to avoid contamination by contact with infective eggs in feces (31) . ...
... Once liquid feces are obtained, the appropriate dose of niclosamide must be given (2 gr orally for adults, 1 gr for children older than 6). Two hours after niclosamide intake, a second purge is administered (30,31) . The whole process must involve abundant oral hydration to avoid dehydration or electrolyte disorders, and to facilitate purge and elimination of the worm. ...
... The tapeworm's head or scolex contains four muscular suckers and a distinctive 'armed' rostellum containing a double row of hooks for attachment to the mucosal lining of the upper small intestine in the human host (Jeri et al., 2004;Flisser, 2013) (Figure 2). Attached to the scolex is the short, unsegmented neck section from which a long chain of several hundred progressively larger and more mature segments or 'proglottids' develop. ...
... Treatment of adult cestode infections is simple and straightforward, using inexpensive and commonly available oral anthelmintics. The two most frequently used drugs for TS are niclosamide (NCL), which has an efficacy of nearly 80%, and praziquantel (PZQ), which is generally accepted to be 95-100% effective (Jeri et al., 2004;Carabin and Traoré, 2014). One Chinese study indicated that pumpkin seeds and/or areca (betel) nut extract are naturally effective taenicides, with the combination demonstrating 89% treatment efficacy (n=115) (Li et al., 2012); further studies are needed to validate these results. ...
https://biblio.ugent.be/publication/8582700
... Hay que tener en cuenta también los aspectos de bioseguridad para el personal de salud, el paciente y su entorno dado que la manipulación de heces infectadas con T. solium puede resultar en cisticercosis o neurocisticercosis. Debe ser realizado bajo supervisión médica para prevenir o manejar efectos adversos de la purga o la medicación, y para evitar la contaminación por contacto con las heces infectivas (31) . ...
... Una vez que se obtienen deposiciones líquidas se debe dar la dosis correspondiente de niclosamida (2 gramos vía oral para adultos, 1 gramo en niños mayores de 6 años). Dos horas después de la niclosamida se administra una segunda purga (30,31) . Todo el proceso debe ser acompañado de abundante hidratación oral, para evitar la deshidratación o trastornos electrolíticos y para facilitar la purga y eliminación del gusano. ...
Neurocysticercosis is a nervous system infection caused by the larvae (cysticercus) of the pork tapeworm (Taenia solium). Neurocysticercosis is the primary cause of acquired epilepsy worldwide and, therefore, a global public health problem. On the other hand, T. solium taeniasis/cysticercosis is one of very few infectious diseases considered to be potentially eradicable. Recently, a large-scale elimination program in Tumbes, Peru, demonstrated the feasibility of interrupting transmission. Based on these advances, a series of initial guidelines are proposed aimed at setting out the foundations for regional and national taeniasis/cysticercosis control programs, with simple and feasible local interventions as a starting point.
... The scolex is rarely available, the staining of proglottids is a laborious procedure and tapeworms may present some abnormalities or may be damaged, making identification difficult [32]. A purge with electrolyte-polyethylene glycol salt (EPS), 2 h before and 2 h after niclosamide treatment, has improved recovery of the scolex and the quality of the expelled proglottids [40]. ...
... ‡ In order to improve the recovery of the scolex and the quality of the expelled proglottids, a purge with electrolyte-polyethylene glycol salt (EPS), 2 h before and 2 h after niclosamide treatment, can be applied [40]. §The efficacy has been assessed mainly in T. saginata taeniasis, using microscopic examination and/or clinical follow-up as test of cure that could have overestimated the efficacy. ...
Neurocysticercosis, the central nervous system's localized form of cysticercosis, is considered to be the leading cause of epilepsy in the developing world. In Europe, the disease mainly imported and affects both immigrants and travellers. However, autochthonous cases of cysticercosis in low-endemic countries could also originate from T. solium carriers (migrants or travellers) who acquired taeniasis overseas. Management of cysticercosis is a challenge for European healthcare providers since they are often hardly aware of this infection and have little familiarity in managing this disease. This paper provides a summary of recommendations concerning screening, diagnosis and management of cysticercosis and T. solium taeniasis in Europe drawn up by nine experts in migrant health and imported diseases with experience in cysticercosis and T. solium taeniasis. This article is protected by copyright. All rights reserved.
... This recovery is difficult because of the disintegration of the proximal end of the worm when modern cestocidal drugs are used [45]. Jeri et al. [46] improved the treatment method to obtain a recognizable tapeworm by using pre-niclosamide and post-niclosamide electrolytepolyethyleneglycol (PEG) salt purges to improve bowel cleaning and collection of the tapeworm scolex, making differentiation between T. saginata and T. solium easier. Nevertheless, since PEG has to be dissolved in 2 L of water, it might not be well accepted/perceived, especially in community studies. ...
... Since people may consume pork meat infected with many cysts, potentially many of these can develop into adult worms within one host. However, an important proportion of infected individuals can harbor multiple tapeworms, as demonstrated in studies by Bustos et al. [46]. It is also possible that some juvenile tapeworms are expelled before they reach maturity. ...
Human neurocysticercosis, caused by the larval
stage of the tapeworm Taenia solium, is an important neurological
disorder reported as a major cause of epilepsy. An
important risk factor for neurocysticercosis is the presence of
human T. solium carriers who, upon open defecation, disseminate
tapeworm eggs, which are infective to both humans and
pigs. In the latter, infection also results in cysticercosis, with
associated health and economic consequences. Control of
T. solium therefore depends greatly on accurate detection
and treatment of carriers. However, the currently available
direct diagnostic tests depend on detection, in feces, of either
parasite stages or parasite antigens and genetic material. The
former are low cost but lack adequate sensitivity and specificity;
the latter are too expensive to be routinely utilized in
endemic communities. Indirect tests based on antibody detection
may only show exposure and not active infection. An
ideal diagnostic test should be one that is low cost and is able
to quickly and reliably detect tapeworm carriers so that appropriate
treatment can be prescribed in order to eliminate the
source of infection. Such a test remains elusive. Efforts
should, therefore, be directed at formulation of a test that is
not only sensitive and specific but also affordable for use in
endemic countries.
... We also included four pigs from a third study, in which 2-monthold pigs were infected with 10,000 activated oncospheres by intracarotid injection [25]. Tapeworms used in these experiments were obtained from patients treated with a single oral dose of 2 g of niclosamide [26]. Tapeworms were kept in transport medium with antibiotics (amphotericin B 0.25 µg/mL, streptomycin 100 µg/mL, and penicillin 10 IU/mL) and was adjusted to a volume of 10 mL of saline at 4 °C. ...
Background
Antigen detection in Taenia solium cysticercosis confirms viable infection in the intermediate host (either pig or human). The reference B158/B60 monoclonal antibody (mAb)-based Ag-enzyme-linked immunosorbent assay (ELISA) has acceptable levels of sensitivity and specificity in human neurocysticercosis with multiple brain cysts, although its sensitivity is lower in cases with single brain cysts, whereas in porcine cysticercosis the assay specificity is affected by its frequent cross-reaction with Taenia hydatigena, another common cestode found in pigs. Our group has produced 21 anti-T. solium mAbs reacting against antigens of the whole cyst, vesicular fluid, and secretory/excretory products, identifying TsW8/TsW5 as the most promising pair of mAbs for an Ag-ELISA.
Methods
We report the use of the TsW8/TsW5 Ag-ELISA to measure cysticercus antigen levels [expressed as optical density (OD) values] in two panels of sera collected from day 0 (baseline) to day 90 postinfection (PI) from pigs experimentally infected with T. solium (n = 26) and T. hydatigena (n = 12). At baseline and on days 28 and 90 PI, we used Bland–Altman (BA) analysis and Lin’s concordance correlation coefficients (CCC) to determine the concordance between the TsW8/TsW5 and the B158/B60 Ag-ELISA.
Results
The TsW8/TsW5 Ag-ELISA was able to efficiently measure circulating antigen levels in T. solium-infected pigs, similar to that obtained with the B158/B60 Ag-ELISA. Almost all paired log-OD differences between assays were within the limits of agreement (LoA) in the BA analysis at baseline and on days 28 and 90 PI (92.3%, 100%, and 100%, respectively), and a high concordance of log-ODs between assays was also found (Lin’s CCC: 0.69, 0.92, and 0.96, respectively, all P < 0.001). In pigs infected with T. hydatigena, almost all paired log-OD differences were within the LoA in the BA analysis, whereas the concordance of log-ODs between assays was low at baseline (Lin’s CCC: 0.24) but increased on days 28 and 90 PI (Lins’ CCC: 0.88 and 0.98, P < 0.001).
Conclusions/significance
The TsW8/TsW5 Ag-ELISA recognizes antigens in pigs with T. solium cysticercosis and is highly concordant with the B158/B60 Ag-ELISA. However, its diagnostic use is hampered by cross-reactions with T. hydatigena, as in other mAb-based Ag-ELISAs.
Graphical Abstract
... Taenia solium eggs (from which the oncospheres will hatch, Singh et al., 2020), are spherical or radial in appearance and found individually or within gravid proglottids. While eggs can be identified through traditional stool examination, it is impossible to discriminate T. solium eggs morphologically from those of T. saginata and other Taenia species ( Jeri et al., 2004). The oncosphere is surrounded by a protective embryophore, measuring approximately 26-43 μm in diameter (Flisser, 2013;Yoshino, 1933c) to protect against external factors in the environment. ...
Infection with the pork tapeworm (Taenia solium) is responsible for a substantial global burden of disease, not only restricted to its impact on human health, but also resulting in a considerable economic burden to smallholder pig farmers due to pig cysticercosis infection. The life-cycle, parasitology and immunology of T. solium are complex, involving pigs (the intermediate host, harbouring the larval metacestode stage), humans (the definitive host, harbouring the adult tapeworm, in addition to acting as accidental intermediate hosts) and the environment (the source of infection with eggs/proglottids). We review the parasitology, immunology, and epidemiology of the infection associated with each of the T. solium life-cycle stages, including the pre-adult/adult tapeworm responsible for human taeniasis; post-oncosphere and cysticercus associated with porcine and human cysticercosis, and the biological characteristics of eggs in the environment. We discuss the burden associated, in endemic settings, with neurocysticercosis (NCC) in humans, and the broader cross-sectoral economic impact associated both with NCC and porcine cysticercosis, the latter impacting food-value chains. Existing tools for diagnostics and control interventions that target different stages of the T. solium transmission cycle are reviewed and their limitations discussed. Currently, no national T. solium control programmes have been established in endemic areas, with further work required to identify optimal strategies according to epidemiological setting. There is increasing evidence suggesting that cross-sectoral interventions which target the parasite in both the human and pig host provide the most effective approaches for achieving control and ultimately elimination. We discuss future avenues for research on T. solium to support the attainment of the goals proposed in the revised World Health Organisation neglected tropical diseases roadmap for 2021–2030 adopted at the 73rd World Health Assembly in November 2020.
... A total of six adult tapeworm specimens were collected from patients treated with a single oral dose (2 g) of niclosamide. 27 Taenias were collected and stored in Falcon 15-mL tubes containing saline solution with antibiotics (10 U/mL penicillin, 100 μg/mL streptomycin, and 0.25 μg/mL amphotericin B) at 4°C until used (within a 4-week period of collection). Species differentiation (T. ...
Neurocysticercosis (NCC), the infection of the human central nervous system (CNS) with larval cysts of Taenia solium causes widespread neurological morbidity. Animal models are crucial for studying the pathophysiology and treatment of NCC. Some drawbacks of current NCC models include differences in the pathogenesis of the model and wild-type parasite, low rates of infection efficiency and lack of reproducibility. We describe a novel porcine model that recreates infection in the CNS with high efficiency. Activated oncospheres, either in a high (45,000-50,000) or low (10,000) dose were inoculated in the common carotid artery of 12 pigs by ultrasound-guided catheterization. Following oncosphere injection, either a high (30 mL) or low (1-3 mL) volume of saline flush was also administered. Cyst burden in the CNS was evaluated independently according to oncosphere dose and flush volume. Neurocysticercosis was achieved in 8/12 (66.7%) pigs. Cyst burden in the CNS of pigs was higher in the high versus the low oncosphere dose category (median: 4.5; interquartile ranges [IQR]: 1-8 and median: 1; IQR: 0-4, respectively) and in the high versus the low flush volume category (median 5.5; IQR: 1-8 and median: 1; IQR: 0-2, respectively), although not statistically different. All cysts in the CNS were viable, whereas both viable and degenerated cysts were found in the musculature. Carotid injection of activated oncospheres in pigs is effective in reproducing NCC. Oncosphere entry into the CNS by way of vasculature mimics wild-type infection, and provides a useful alternative for future investigations on the pathogenesis and antiparasitic treatment of NCC.
... The anthelmintics of choice are niclosamide (NCZ) (efficacy around 85%) and praziquantel (PZQ) (efficacy around 95%) ( Jeri et al., 2004;Rajshekhar, 2004). The use of PZQ requires an extra degree of caution. ...
Taenia solium taeniasis/cysticercosis is a neglected parasitic zoonosis with significant economic and public health impacts. Control measures can be broadly grouped into community health education, improvements in hygiene and sanitary conditions, proper meat handling at household and community level, improved standards of meat inspection, pig management, treatment of individual patients and possibly human populations, and treatment and/or vaccination of porcine populations. This manuscript looks critically into currently existing control options and provides suggestions on which (combination of) tools would be most effective in the control of T. solium taeniasis/cysticercosis in sub-Saharan Africa. Field data and disease transmission simulations suggest that implementation of a single intervention control strategy will not lead to a satisfactory reduction of disease morbidity or transmission. A feasible strategy to combat T. solium taeniasis/cysticercosis would include a combination of approaches focussing on both human (health education and treatment) and animal host (management, treatment and vaccination), which can vary for different communities and different geographical locations. Selection of the specific strategy depends on cost-effectiveness analyses based on solid field data, currently unavailable, though urgently needed; as well as on health priorities and resources of the country. A One Health approach involving medical, veterinary, environmental and social sectors is essential for T. solium to be controlled and eventually eliminated. Finally the success of any intervention is largely dependent on the level of societal and political acceptance, commitment and engagement.
... Usually the numbers of of praziquantel at 10mg/kg b.w. [24]. cysticerci are low in bovine; hence many cases remain ...
The prevalence of bovine cysticercosis was established using routine postmortem inspection of 3450 carcasses of buffaloes slaughtered in 2014 in Kaliouba governorate, among which 313 (9.07%) were detected as harbouring cysticercosis lesions using meat inspection process. The cysts were examined macroscopically for description of their morphology and constituents and classified as viable or degenerating. Viable cysts were microscopically confirmed for demonstration of protoscolex. Out of 100 of patients offered taenicidal drugs examined by microscopic examination through direct and sedimentation of fecal samples, 6 (6%) were positive for Taenia saginata (T. saginata) eggs. Histological sections of 6 gravid proglottids were identified as T. saginata. We used a biomolecular assay targeting the HDP2 gene for developing PCR assay in 20 viable cysts and 6 gravid proglottids. An HDP2 gene-PCR amplification product of the taeniid samples of T. saginata is approximately 599bp. Partial sequences were generated after gel purification of PCR amplified products of HDP2 gene with sequence analysis and subsequent phylogeny to compare these sequences to those from known strains of T. saginata circulating globally and retrieved from GenBank. Most isolates with accession No. KT027580 are closely related to T. saginata based on the similarity of nucleotide sequences and phylogenetic relationships. In conclusion, this work indicated high prevalence rate of bovine cysticercosis and T. saginata, both morphological examination of the parasite and molecular analysis using bioinformatic tools identified the metacestode and revealed typical taeniid features confirmed to Taenia saginata.
... Adult T. solium tapeworms were collected from human patients following the niclosamide regimen. 19 Species differentiation was determined by histologic analysis (parasite morphologic analysis) and PCR with restriction fragment length polymorphism, as previously reported. 20 Eggs were obtained from gravid proglottids and incubated in sodium hypochlorite (0.75%) for 10 minutes at 4 C to facilitate in vitro hatching of oncospheres. ...
Neurocysticercosis is caused by Taenia solium infecting the central nervous system and is the leading cause of acquired epilepsy and convulsive conditions worldwide. Research into the pathophysiology of the disease and appropriate treatment is hindered by lack of cost-effective and physiologically similar animal models. We generated a novel rat neurocysticercosis model using intracranial infection with activated T. solium oncospheres. Holtzman rats were infected in two separate groups: the first group was inoculated extraparenchymally and the second intraparenchymally, with different doses of activated oncospheres. The groups were evaluated at three different ages. Histologic examination of the tissue surrounding T. solium cysticerci was performed. Results indicate that generally infected rats developed cysticerci in the brain tissue after 4 months, and the cysticerci were observed in the parenchymal, ventricle, or submeningeal brain tissue. The route of infection did not have a statistically significant effect on the proportion of rats that developed cysticerci, and there was no dependence on infection dose. However, rat age was crucial to the success of the infection. Epilepsy was observed in 9% of rats with neurocysticercosis. In histologic examination, a layer of collagen tissue, inflammatory infiltrate cells, perivascular infiltrate, angiogenesis, spongy change, and mass effect were observed in the tissue surrounding the cysts. This study presents a suitable animal model for the study of human neurocysticercosis.
Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.
... In previous studies, genetic markers such as the first and second internal transcribed spacers (ITS-1, ITS-2) and mitochnodrial cytochrome c oxidase subunit (cox1) have been used to reveal genetic differentiation between T. solium and T. asicatia (Jeon et al., 2011a, b;Nkouawa et al., 2009). Due to their sufficient differences in reproductive biology, host preference and gene sequences, these two Taenia taxa are considered as separated species (Jeri et al., 2004;Jeon et al., 2011a, b;Nkouawa et al., 2009). T. solium and T. asicatia have complex life cycles and can be transmitted between pigs and humans. ...
Taenia solium and Taenia asiatica are zoonotic parasites which are transmitted between pigs and humans, with pigs acting as the intermediate host and humans as the definitive host. The aim of the present study was to compare the microRNA (miRNA) profiles between T. solium and T. asiatica by Solexa deep sequencing and bioinformatic analyses. A total of 18.26 and 15.24 million reads with high quality and three new miRNAs were obtained in each species, respectively. The two cestodes shared nearly the same level of total sRNA, but the known miRNAs were in a very different manner. Nucleotide guanine (G) and uracil (U) were the most frequently used first nucleotide in both T. solium and T. asiatica, respectively. Furthermore, it was also found that there were great differences in the kinds and copy numbers of miRNAs among the two Taenia species, which might indicate the different evolutions in the two parasites. To our knowledge, this is the first report on the characterization of the miRNA profiles for the two Taenia cestodes, and it would lay a foundation for further functional studies of miRNAs of T. solium and T. asiatica.
... Treatment consisted of niclosamide and an electrolytepolyethyleneglycol solution (EPS) purge (NuLYTELY, Asofarma, Argentina). [7] Adults were treated with 2 g of niclosamide and 2 L of EPS, which was given 2 h before and after treatment. Children.34 ...
Neurocysticercosis is a leading cause of seizures and epilepsy in most of the world, and it occurs when Taenia solium larval cysts infect the central nervous system. T. solium tapeworm infection is endemic in much of Peru, but there are scarce data on the prevalence in many rural highland communities where it is likely to be hyper-endemic. Peace Corps Volunteers live and work in these communities; however, to our knowledge, they have not been used to facilitate public health research.
We utilized Peace Corps Volunteers to estimate the prevalence of T. solium tapeworm infection in seven rural communities in northern Peru. A convenience non-random sampling frame was used. Peace Corps Volunteers facilitated the collection of stool samples (N = 2,328), which were analyzed by sedimentation and microscopy. Niclosamide treatment and purgation preceded species identification, which was done by PCR-REA.
Taenia sp. egg-positive stool samples were found in three of the seven communities we surveyed. The overall prevalence of Taenia sp. egg positivity was 2.1% (49/2,328) (95% CI = 1.6-2.8%) with prevalence up to 4.3% (42/977) (95% CI = 3.1-5.8%) by community. All 34 of the specimens tested by PCR-REA were T. solium. The overall prevalence of T. solium tapeworm infection was 1.5% (34/2,328) (95% CI = 1.0-2.0%). Prevalence up to 2.9% (28/977) (95% CI = 1.9-4.1%) by community was observed.
This study recorded high T. solium tapeworm prevalence, and identified hyper-endemic rural communities. It demonstrates that synergy between researchers and Peace Corps Volunteers can be an effective means to conducting large-scale, community-based studies in remote areas of Peru.
... All of these serum samples were collected in regions where the transmission of cysticercosis/taeniasis does not occur, except for the serum samples from persons with Taenia saginata taeniasis, which were collected in Peru. Differentiation of T. solium and T. saginata was made after examining the proglottids or by PCR (18)(19)(20). ...
One of the most well-characterized tests for diagnosing neurocysticercosis (NCC) is the enzyme-linked immunoelectrotransfer
blot (EITB) assay developed at the CDC, which uses lentil lectin-bound glycoproteins (LLGP) extracted from Taenia solium cysticerci. Although the test is very reliable, the purification process for the LLGP antigens has been difficult to transfer
to other laboratories because of the need for expensive equipment and technical expertise. To develop a simpler assay, we
previously purified and cloned the diagnostic glycoproteins in the LLGP fraction. In this study, we evaluated three representative
recombinant or synthetic antigens from the LLGP fraction, individually and in different combinations, using an immunoblot
assay (recombinant EITB). Using a panel of 249 confirmed NCC-positive and 401 negative blood serum samples, the sensitivity
of the recombinant EITB assay was determined to be 99% and the specificity was 99% for diagnosing NCC. We also tested a panel
of 239 confirmed NCC-positive serum samples in Lima, Peru, and found similar results. Overall, our data show that the performance
characteristics of the recombinant EITB assay are comparable to those of the LLGP-EITB assay. This new recombinant- and synthetic
antigen-based assay is sustainable and can be easily transferred to other laboratories in the United States and throughout
the world.
... Recently, anti-Taenia drugs such as niclosamide and in niclosamide-resistant cases, praziquantel and mepacrine are utilized along with purgatives like electrolyte-polyethyleneglycol salt for expulsion of scolices and proglottids. [7,8,9] Examination of the expulsed scolices and gravid proglottids helps in differentiation of Taenia spp. [10] These structures after isolation from fecal debris are stored in 10% 20/02/17 11:34 AM Laboratory diagnosis of Taenia asiatica in humans and animals Page 2 of 6 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3889088/ ...
Taenia asiatica is a recently described species known to cause intestinal teniasis in humans and cysticercosis in animals. This species has close morphological resemblance to Taenia saginata and has a life cycle resembling Taenia solium, hence has been posing diagnostic dilemma and had been the reason for its comparatively late discovery. Recent diagnostic tools such as serological and molecular techniques have thrown light on its exact prevalence in the endemic countries. Hence introduction of utilization of these techniques in addition to the routine morphological analysis would be helpful in diagnosis of T. asiatica infections and early implementation of preventive measures.
... Yumurtalar, gaitada seyrek olarak görülebilir. Sığır ve domuz tenyalarının yumurtaları, ışık mikroskobu ile birbirinden ayırt edilemez; spesifik testler gerekir (6) . Yurdumuzun bazı yerleşim birimlerinde alt yapı yetersizliği, eğitim eksikliği gibi nedenlerle tropikal ülkelerdeki kadar olmasa da gastrointestinal parazitik enfeksiyonlar azımsanamayacak ölçüde sıktır. ...
In this paper we reported a case of an 38-year-old man, in whom a taenia saginata was expelled through the mouth. This kind of expulsion is very rare. This case has been reported to emphasize the the differential diagnosis to be taken while handling the epigastria pain, nausea, and vomiting of patients with frequent admissions in the emergency department setting.
... However, overlapping between the numbers of uterine branches of these species has been described; it is also relatively uncommon to obtain a whole adult tapeworm with an intact scolex following treatment. Recently, Jeri et al. (2004) improved the treatment method to obtain a recognizable tapeworm, making differentiation between T. solium and T. saginata easier. Proglottids can be stained with the Semichon's acetocarmine stain method to allow morphological differentiation. ...
... Niclosamide followed by a purgative is a good alternative because tapeworms are usually completely recovered, including the scolex, being crucial in the identification and differentiation between species. In addition, this drug is not absorbed in the intestine avoiding the risk of causing neurological symptoms when the carrier also has NC (Jeri et al., 2004). Albendazole has also been used to treat taeniasis although Horton (2000) mentions a low efficacy (85% in 7 studies). ...
Taeniasis-cysticercosis is caused by Taenia saginata and Taenia solium. Adult Taenia spp. are always intestinal parasites highly specific for man. Bovines and pigs act as intermediate hosts for T. saginata and T. solium, respectively. Metacestodes are located in the tissues, commonly the muscles; larvae of T. solium can also occur in nervous tissues and cause neurocysticercosis in man, considered the most common cause of acquired epilepsy in endemic countries. Consumption of undercooked pork, free-roaming pigs with access to human faeces, are key factors in the occurrence of T. solium. In Ecuador in particular, T. solium is endemic in the Andean region and rare or absent in most costal regions. This study focused on the understanding of epidemiology of the taeniasis-cysticercosis complex in two Andean regions of Ecuador and the improvement of the diagnostic tools to this aim.
This thesis is divided into four parts: (1) an introduction formulating the problems, underpinned by a general review of the literature leading to the description of the objectives of this study (chapter 1); (2) the development of highly sensitive and specific PCR-based techniques to detect and to differentiate T. solium, T. saginata and Hymenolepis nana somata (chapter 2)and tapeworm-DNA extracted from faecal samples (chapter 3); (3) an assessment of the taeniasis-cysticercosis situation in two endemic areas in the Ecuadorian Andes (chapters 4 and 5) and (4) a general discussion where the results are commented in a broader perspective (chapter 6).
A general introduction in chapter 1outlines the problem of taeniasis-cysticercosis with an assessment of the situation in Ecuador and the position of the present study. A review of literature, on important cysticercosis-related topics like origin, history, morphology, life cycle and epidemiology is given with i.a. the main shortcomings on control and diagnosis. The emphasis of this review is on the epidemiological aspects and diagnostic techniques used to estimate the prevalence of taeniasis and cysticercosis, with particular reference to PCR-based assays for the diagnosis of taeniasis. At the end of this chapter, the objectives are presented, the main aim being to gain a better understanding of the taeniasis-cysticercosis problem in Ecuador by applying improved diagnostic tools.
Chapter 2 describes the development of a PCR based tool to underpin current diagnostic methods, i.e., morphological and iso-enzymatic studies of proglottids. A PCR test complemented with restriction enzyme analysis was modified by redesigning one of the primers to reduce non-specific amplifications experienced when using field samples. The use of these new, highly specific primers and the restriction enzyme DdeI led to the development of a diagnostic assay allowing clear differentiation between T. saginata and T. solium proglottids in field samples. This assay confirmed the presence of T. saginata in Ecuador.
In chapter 3, based on the previous chapter, an improved PCR-RFLP method to differentiate DNA from T. solium and T. saginata, extracted from faeces, was developed. New primers were tested with improved specificity to amplify parasite DNA in faecal samples. For this purpose, three different faeces extraction protocols were compared i.e. the commercial QIAamp®DNA stool mini kit; the guanidium thiocyanate/zirconium matrix method (Boom) and DNA isolation based on a sequence-capture technique (Mangiapan). The PCR-RFLP assay was used on faecal extracts from 35 known Taenia carriers collected before anthelmintic treatment. Both QIAgen and Boom protocols showed non-specific bands, which in Mangiapan were not observed in negative samples from Ecuador, though they were present in negative samples from Belgium, complicating the interpretation of the PCR. The PCR-RFLP assay on faecal extracts from35 known tapeworm carriers detected 27 samples positive for T. solium and 8 for T. saginata. Restriction with DdeI enzyme gave clear and distinctive profiles for T. solium, T. saginata and H. nana; the primers developed in this work amplified neither Hymenolepis diminuta nor Diphyllobothrium latum. This new PCR-RFLP assay has potential as a supporting tool for the specific diagnosis of Taenia spp., following preselection of samples by standard coprological assays. However, the appearance of non-specific bands in some samples requires further improvement of the assay.
Chapter 4, describes an epidemiological study in the northern Andes with the first report of T. saginata in Ecuador, urging reconsideration of some assumptions in the epidemiology of the taeniasis/cysticercosis complex in this country. Therefore, data on the infection of both tapeworms in man and animals in Pichincha and Imbabura provinces in the Andean region, north of Quito, were compiled. On post mortem inspection 3 out of 806 (0.37%) bovine carcasses had T. saginata metacestodes, however, 35 sera out of 869 (4.03%) showed circulating antigen in a monoclonal antibody-based sandwich ELISA (Ag-ELISA). Porcine cysticercosis was detected in 15 out of 2,896 (0.52%) carcasses and 93 out of 1,032 serum samples (9.01%) were95page 109The epidemiology of Taenia spp. and cysticercosis in Ecuador positive in Ag-ELISA. In humans, 4.99% (215out of 4,306) antigen positives were found, whereas coprological examination of 1,935 stools resulted in 30 positive cases (1.55%). The limited number of adult tapeworms (29) that were collected does not allow affirm conclusions on the proportion of each species, but in total 21 specimens were identified as T. saginata and 8 as T. solium. These data have been discussed in view of the epidemiology of human cysticercosis.
In chapter 5, data of a second epidemiological study, carried out in an endemic community in the southern Ecuadorian Andes, are given. The poor living conditions in this region presumed higher prevalences of T. solium cysticercosis than in the North. The study was undertaken in Limones, a rural community in Loja province with a population of 1,059 people and 1,148 pigs. Participation was high: 800 serum samples and 958 stool samples of the people were collected. In addition, 646pigs were tongue inspected. Circulating antigen was detected by Ag-ELISA in 2.25% of the human population. Intestinal taeniasis was detected in 1.46% of the samples by the formalin-ether technique; following treatment and recovery of tapeworm fragments, all were identified as T. solium. Porcine cysticercosis was diagnosed in 3.56% of the pigs by tongue inspection. Unfortunately antigen detection in pigs was seriously hampered by the highly prevalent Taenia hydatigena. In addition, enzyme linked immune electrotransfer blot (EITB) was performed on a subset group of 100 humans to confirm the results of the Ag-ELISA. One hundred serum samples from pigs were also analysed by EITB. It appeared that 43 and 74% of humans and pigs, respectively had antibodies against T. soliumcysticerci. It is concluded that contrary to the high exposure of the human population to T. solium as suggested by EITB, the number of active cysticercosis cases, diagnosed by Ag-ELISA, was low, which may indicate endemic stability. The further use of complementary diagnostic methods for a better understanding of the epidemiology of T. solium is suggested.
In the general discussion (Chapter 6), the results of the different chapters are discussed, highlighting the most important findings and implications for the understanding of the taeniasis-cysticercosis complex. In this chapter, the importance using highly sensitive and specific diagnostic tools based on molecular biology is emphasised. Comparison of the observations in the North and the South are indicative for an endemic stability in the southern community under study. Frequent contact contrasted with few cases of active cysticercosis as evidenced by respectively, antibody and antigen detection. In the northern study, in spite of proportionally less adult T.solium, the prevalence of active cysticercosis was higher. Both these surveys are prelimary studies and need further confirmation by i.a. simultaneous use of antibody and antigen detection in various locations combined with improved detection of the carriers of adult tapeworms. Options for control of this disease are presented and their potential for use in Ecuador are discussed.
... Still, sensitivity remains low: 30-50% for finding tapeworm proglottids or eggs (Pawlowski, 2006). Anthelmintic treatment and the use of a purge with electrolyte-polyethyleneglycol salt (EPS) before and after treatment improves the recovery of the scolex and the quality of the expelled proglottids (Jeri et al., 2004). However, the scolex is recovered in only ±30% of patients. ...
... The staining procedure is described inter alia by Morgan and Hawkins [378]. In order to improve the recovery of the scolex and the quality of the expelled proglottids, a purge with electrolyte-polyethyleneglycol salt (EPS), (a product which is commonly used to prepare patients undergoing colonoscopy), two hours before and two hours after niclosamide treatment can be applied [291]. However, even using this EPS regimen, the scolex is recovered in only about one third of patients. ...
... Niclosamide is active against intestinal tapeworms with about 85% of efficacy (Pawlowski et al., 2005), but not against tissue-located cysticerci, as it is barely absorbed in the gastrointestinal tract and therefore recommended in mass treatment (Gemmell et al., 1983;Allan et al., 2002). However, in a previous study in Peru only 30% of taeniasis carriers expelled intact tapeworms after niclosamide use (Jeri et al., 2004). Again, it might also be difficult to recover the expelled scolex following niclosamide therapy (Pawlowski et al., 2005). ...
Taeniasis refers to the infection with adult tapeworms of Taenia spp. in the upper small intestine of humans, which is also a cause of cysticercosis infection in either both humans and/or animals. Currently the most commonly applied anthelminthics for treatment of taeniasis are praziquantel and niclosamide. Praziquantel is very effective, but has the risk of induction of epileptic seizures or convulsions in carriers with asymptomatic concurrent neurocysticercosis. In contrast, niclosamide is safe and effective, but is not readily available in many endemic countries including China. In the current community-based study, we assessed the curative effect of either pumpkin seeds or areca nut extract alone in taeniasis, and also looked at synergistic effects of these two herb drugs on tapeworms. In the study group with the pumpkin seed/areca nut extract treatment, 91 (79.1%) of 115 suspected taeniasis cases (with a history of expulsion of proglottids within the previous one year) released whole tapeworms, four (3.5%) expelled incomplete strobila, and no tapeworms or proglottids were recovered in the remaining 20 cases. In these 115 persons, 45 were confirmed as taeniasis before treatment by microscopy and/or coproPCR. Forty (88.9%) of 45 confirmed cases eliminated intact worms following treatment. The mean time period for complete elimination of tapeworms in 91 taeniasis cases was 2h (range 20min to 8h 30min), and 89.0% (81) of 91 patients discharged intact worms within 3h after drug administration. In Control Group A with treatment of pumpkin seeds alone, 75.0% (9/12) of confirmed taeniasis cases expelled whole tapeworms, but the mean time period for complete elimination was about 14h 10min (range 3h 20min to 21h 20min), which was much longer than that (2h) for the study group, whereas in Control Group B treated with areca nut extract alone, only 63.6% (7/11) of taeniasis cases discharged whole tapeworms, and the mean time period was 6h 27min (range 1-22h). Mild side effects included nausea and dizziness in about 46.3% of patients with the pumpkin seeds/areca nut extract treatment, but all discomforts were transient and well tolerated. In conclusion, a synergistic effect of pumpkin seed and areca nut extract on Taenia spp. tapeworms was confirmed in the current study, primarily in producing an increased rate of effect on tapeworm expulsion (average time 2h for combination vs 6-21h for individual extracts). The pumpkin seed/areca combined treatment was indicated to be safe and highly effective (89%) for human taeniasis.
Background
Neurocysticercosis (NCC) is the infection of the human central nervous system (CNS) by Taenia solium larvae that cause significant neurological morbidity. Studies on NCC pathophysiology, host-parasite interactions or therapeutic agents are limited by the lack of suitable animal models. We have previously reported that carotid injection of activated T . solium oncospheres directs parasites into the CNS and consistently reproduces NCC. This study assessed the minimal dose required to consistently obtain NCC by intracarotid oncosphere injection and compared antigen and antibody response profiles by dose-group.
Methods/Principal findings
Three groups of pigs were infected with either 2500 (n = 10), 5000 (n = 11), or 10000 (n = 10) oncospheres. Two pigs died during the study. Necropsy exam at day 150 post-infection (PI) demonstrated viable NCC in 21/29 pigs (72.4%), with higher NCC rates with increasing oncosphere doses (4/9 [44.4%], 9/11 [81.8%] and 8/9 [88.9%] for 2500, 5000, and 10000 oncospheres respectively, P for trend = 0.035). CNS cyst burden was also higher in pigs with increasing doses ( P for trend = 0.008). Viable and degenerated muscle cysticerci were also found in all pigs, with degenerated cysticerci more frequent in the 2500 oncosphere dose-group. All pigs were positive for circulating parasite antigens on ELISA (Ag-ELISA) from day 14 PI; circulating antigens markedly increased at day 30 PI and remained high with plateau levels in pigs infected with either 5000 or 10000 oncospheres, but not in pigs infected with 2500 oncospheres. Specific antibodies appeared at day 30 PI and were not different between dose-groups.
Conclusion/Significance
Intracarotid injection of 5000 or more oncospheres produces high NCC rates in pigs with CNS cyst burdens like those usually found in human NCC, making this model appropriate for studies on the pathogenesis of NCC and the effects of antiparasitic treatment.
Combined community health programs aiming at health education, preventive anti-parasitic chemotherapy, and vaccination of pigs have proven their potential to regionally reduce and even eliminate Taenia solium infections that are associated with a high risk of neurological disease through ingestion of T . solium eggs. Yet it remains challenging to target T . solium endemic regions precisely or to make exact diagnoses in individual patients. One major reason is that the widely available stool microscopy may identify Taenia ssp. eggs in stool samples as such, but fails to distinguish between invasive ( T . solium ) and less invasive Taenia ( T . saginata , T . asiatica , and T . hydatigena ) species. The identification of Taenia ssp. eggs in routine stool samples often prompts a time-consuming and frequently unsuccessful epidemiologic workup in remote villages far away from a diagnostic laboratory. Here we present “mail order” single egg RNA-sequencing, a new method allowing the identification of the exact Taenia ssp. based on a few eggs found in routine diagnostic stool samples. We provide first T . solium transcriptome data, which show extremely high mitochondrial DNA (mtDNA) transcript counts that can be used for subspecies classification. “Mail order” RNA-sequencing can be administered by health personnel equipped with basic laboratory tools such as a microscope, a Bunsen burner, and access to an international post office for shipment of samples to a next generation sequencing facility. Our suggested workflow combines traditional stool microscopy, RNA-extraction from single Taenia eggs with mitochondrial RNA-sequencing, followed by bioinformatic processing with a basic laptop computer. The workflow could help to better target preventive healthcare measures and improve diagnostic specificity in individual patients based on incidental findings of Taenia ssp. eggs in diagnostic laboratories with limited resources.
Tapeworms are a type of platyhelminth, or flatworm, and make up the taxonomic class Cestoda. Infections by tapeworms cause significant morbidity to humans worldwide as well as major production losses in livestock. Adult tapeworms live within the gastrointestinal tract of their definitive hosts, which can be human, other mammals, or fish. Several tapeworms that infect humans are named after their intermediate host, for example, the porcine tapeworm and the bovine tapeworm. In this chapter tapeworm species from four different genera are reviewed: Taenia spp., Diphyllobothrium spp., Hymenolepis spp., and Dipylidium spp. The epidemiology, primary mode of transmission, definitive and accidental hosts, clinical manifestation, diagnostic methods, and treatment options are described for each.
Taenia solium is known to cause human cysticercosis while T. saginata does not. Comparative in vitro and in vivo studies on the oncosphere and the postoncospheral (PO) forms of T. solium and T. saginata may help to elucidate why cysticercosis can occur from one and not the other. The aim of this study was to use in vitro culture assays and in vivo models to study the differences in the development of the T. solium and T. saginata oncosphere. Furthermore, this study aimed to evaluate the expression of cytokines and metalloproteinases (MMPs) in human peripheral blood mononuclear cells (PBMCs), which were stimulated by these oncospheres and PO antigens. T. solium and T. saginata activated oncospheres (AO) were cultured in INT-407 and HCT-8 intestinal cells for 180 days. The T. solium began to die while the T. saginata grew for 180 days and developed to cysticerci in INT-407 cells. Rats were inoculated intracranially with AO and PO forms of either T. saginata or T. solium. Rats infected with T. solium AO and PO forms developed neurocysticercosis (NCC), while those infected with the T. saginata did not. Human PMBCs were stimulated with antigens of AO and PO forms of both species, and the production of cytokines and metalloproteinases (MMPs) was measured. The T. solium AO antigen stimulated a higher production of IL-4, IL-5, IL-13, IFN-γ, and IL-2 cytokines compared to T. saginata AO. In the PO form, the T. saginata PO antigen increased the production of IL-4, IL-5, IL-13, IFN-γ, IL-1β, IL-6, IL-10, TNF-α and IL-12 cytokines compared to T. solium, suggesting that this global immune response stimulated by different forms could permit survival or destruction of the parasite depending of their life-cycle stage. Regarding MMPs, T. solium AO antigen stimulated a higher production of MMP-9 compared to T. saginata AO antigen, which may be responsible for altering the permeability of intestinal cells and facilitating breakdown of the blood-brain barrier during the process of invasion of host tissue.
Background:
The distribution of Taenia saginata in the Americas is unclear. Establishing the distribution, economic burden, and potentials for control of bovine cysticercosis is increasingly important due to the growing demand for beef. This paper aims to take the first step and reviews the recent distribution of T. saginata taeniosis and bovine cysticercosis on a national level within the Americas.
Methods:
We undertook a systematic review of published and grey literature for information on the occurrence, prevalence, and geographical distribution of bovine cysticercosis and human taeniosis in the 54 countries and territories of the Americas between January 1st, 1990 and December 31st, 2017. Data on bovine cysticercosis from OIE reports from 1994 to 2005 were also included.
Results:
We identified 66 papers from the Americas with data on the occurrence of taeniosis or bovine cysticercosis and an additional 19 OIE country reports on bovine cysticercosis. Taeniosis was reported from 13 countries, with nine of these countries reporting specifically T. saginata taeniosis, and four countries reporting non-species specific taeniosis. The reported prevalence of taeniosis ranged between 0.04-8.8%. Bovine cysticercosis was reported from 19 countries, nine identified through the literature search, and an additional 10 identified through the OIE country reports for notifiable diseases. The reported prevalence of bovine cysticercosis ranged between 0.1-19%. Disease occurrence was restricted to 21 countries within the Americas, the majority from the mainland, with the only island nations reporting either bovine cysticercosis or taeniosis being Cuba, Haiti, and the US Virgin Islands.
Conclusions:
Taenia saginata is widely distributed across 21 of the 54 countries in the Americas, but insufficient epidemiological data are available to estimate the subnational spatial distribution, prevalence, incidence and intensity of infections. This needs to be addressed through active surveillance and disease detection programmes. Such programmes would improve the data quantity and quality, and may enable estimation of the economic burden due to bovine cysticercosis in the region in turn determining the requirement for and cost-effectiveness of control measures.
Cestodes, or tapeworms, vary greatly in size and behavior but have similar morphology consisting of a head, called a scolex, a neck, and a worm body, called a strobila, which is formed by body segments called proglottids. T. saginata, T. solium, and T. asiatica. The life cycles of these Taenia species are similar. As definitive host, humans acquire intestinal infection with these cestodes by ingestion of undercooked meat—pork in the case of T. solium and T. asiatica and beef in the case of T. saginata—containing encysted larvae termed cysticercus. This tapeworm infection is called taeniasis. As intermediate host, humans acquire tissue infection of cysticerci by ingestion of T. solium eggs. After ingestion, the eggs mature into metacestodes, which are infective larvae capable of encysting in tissues. This infection is called cysticercosis. T. solium is the only species known to cause significant human pathology; most commonly larvae encyst in the central nervous system (CNS), which is called neurocysticercosis. T. saginata and T. asiatica are similar morphologically and closely related genetically. They cause limited pathology in humans but significant economic losses in the livestock industry.
Foodborne parasites are a source of human parasitic infection. Zoonotic infections of humans arise from a variety of domestic and wild animals, including sheep, goats, cattle, camels, horses, pigs, boars, bears, felines, canids, amphibians, reptiles, poultry, and aquatic animals such as fishes and shrimp. Therefore, the implementation of efficient, accessible, and controllable inspection policies for livestock, fisheries, slaughterhouses, and meat processing and packaging companies is highly recommended. In addition, more attention should be paid to the education of auditors from the quality control (QC) and assurance sectors, livestock breeders, the fishery sector, and meat inspection veterinarians in developing countries with high incidence of zoonotic parasitic infections. Furthermore, both the diagnosis of zoonotic parasitic infections by inexpensive, accessible, and reliable identification methods and the organization of effective control systems with sufficient supervision of product quality are other areas to which more attention should be paid. In this review, we present some examples of successful inspection policies and recent updates on present conventional, serologic, and molecular diagnostic methods for zoonotic foodborne parasites from both human infection and animal-derived foods.
Helminths are multicellular eukaryotic organisms that are common parasites of the human gastrointestinal tract. There are three major groups of helminth that can cause human disease: nematodes, trematodes and cestodes. Nematodes are round worms with a tubular gut, including the genus Enterobius, Trichuris, Trichinella, Capillaria, Trichostrongylus, Strongyloides, Ascaris, Necator and Ancylostoma, Angiostrongylus, Anisakis and Eustrongylides. There are two groups of flatworms: trematodes and cestodes. Trematodes, or flukes, have a blind gut and include the genus Schistosoma, Clonorchis, Opisthorchis, Fasciola, Fasciolopsis, Dicrocoelium, Echinostoma, Heterophyae and Metagonimus. The cestodes, or tapeworms, include Diphyllobothrium, Taenia, Hymenolepis and Echinococcus. Historically, infestation with intestinal helminths has been a normal part of the human condition. Epidemiological studies of inflammatory bowel disease and other diseases caused by immune dysregulation suggest a possible protective role for helminth infections in these conditions. According to the hygiene hypothesis, the loss of helminth exposure which has accompanied socioeconomic improvements has impaired the function of immune regulatory circuits that previously protected humans from immunologic diseases.
Paciente femenino de 18 años procedente de zona rural, Ya-guacire, Francisco Morazán, al sur de la capital, Honduras, con historia de dolor abdominal tipo cólico en epigastrio de un día de evolución y tres episodios eméticos, con expulsión de segmento de estróbila de Taenia spp, el cual fue enviado al servicio de parasito-logía del Hospital Escuela sin más datos. Como se puede observar en la imagen, medía 34cm de longitud, formado por proglótidos in-maduros, que no permiten especiación. Un examen de heces reveló únicamente quistes de Entamoeba coli. La droga de elección para teniasis administrada bajo vigilancia es niclosamida (Yomesán) aunque no es 100% eficaz. 1 Se recomienda un purgante suave 1-2 horas después para acelerar la expulsión de Taenia spp e identifi-car la especie cuando se encuentran proglótidos maduros, grávidos y/o el escólex. 1 La expulsión oral de segmentos de Taenia spp por peristaltismo inverso es un episodio raro, si se expulsan proglótidos grávidos, podría causar cisticercosis por autoinfección. Una bús-queda virtual rescató únicamente 4 casos similares publicados en Chile, 2 India (2 casos), 3 Sudán 4 y todos identificados como Taenia saginata, considerada inocua. Este es el primer caso documentado de Honduras que demuestra la posibilidad de expulsar segmentos de Taenia spp por peristaltismo inverso. Recibido para publicación el 10/12, aceptado el 10/12 Correspondencia: Dra. Rina Kaminsky. Servicio de parasitología, departamento de laboratorio clínico, 2° piso, Hospital Escuela Universitario, Tegucigalpa, Honduras. Teléfono: (504) 2232 2322
Background:
The transitional period between the oncosphere and the cysticercus of Taenia solium is the postoncospheral (PO) form, which has not yet been completely characterized. The aim of this work was to standardize a method to obtain T. solium PO forms by in vitro cultivation. We studied the morphology of the PO form and compared the expression of antigenic proteins among the PO form, oncosphere, and cysticerci stages.
Methodology/principal findings:
T. solium activated oncospheres were co-cultured with ten cell lines to obtain PO forms, which we studied at three stages of development-days 15, 30, and 60. A high percentage (32%) of PO forms was obtained using HCT-8 cells in comparison to the other cell lines. The morphology was observed by bright field, scanning, and transmission electron microscopy. Morphology of the PO form changed over time, with the six hooks commonly seen in the oncosphere stage disappearing in the PO forms, and vesicles and microtriches observed in the tegument. The PO forms grew as they aged, reaching a diameter of 2.5 mm at 60 days of culture. 15-30 day PO forms developed into mature cysticerci when inoculated into rats. Antigenic proteins expressed in the PO forms are also expressed by the oncosphere and cysticerci stages, with more cysticerci antigenic proteins expressed as the PO forms ages.
Conclusions/significance:
This is the first report of an in vitro production method of T. solium PO forms. The changes observed in protein expression may be useful in identifying new targets for vaccine development. In vitro culture of PO form will aid in understanding the host-parasite relationship, since the structural changes of the developing PO forms may reflect the parasite's immunoprotective mechanisms. A wider application of this method could significantly reduce the use of animals, and thus the costs and time required for further experimental investigations.
Background:
Infections with Taenia solium are the most common cause of adult acquired seizures worldwide, and are the leading cause of epilepsy in developing countries. A better understanding of the genetic diversity of T. solium will improve parasite diagnostics and transmission pathways in endemic areas thereby facilitating the design of future control measures and interventions. Microsatellite markers are useful genome features, which enable strain typing and identification in complex pathogen genomes. Here we describe microsatellite identification and characterization in T. solium, providing information that will assist in global efforts to control this important pathogen.
Methods:
For genome sequencing, T. solium cysts and proglottids were collected from Huancayo and Puno in Peru, respectively. Using next generation sequencing (NGS) and de novo assembly, we assembled two draft genomes and one hybrid genome. Microsatellite sequences were identified and 36 of them were selected for further analysis. Twenty T. solium isolates were collected from Tumbes in the northern region, and twenty from Puno in the southern region of Peru. The size-polymorphism of the selected microsatellites was determined with multi-capillary electrophoresis. We analyzed the association between microsatellite polymorphism and the geographic origin of the samples.
Results:
The predicted size of the hybrid (proglottid genome combined with cyst genome) T. solium genome was 111 MB with a GC content of 42.54%. A total of 7,979 contigs (>1,000 nt) were obtained. We identified 9,129 microsatellites in the Puno-proglottid genome and 9,936 in the Huancayo-cyst genome, with 5 or more repeats, ranging from mono- to hexa-nucleotide. Seven microsatellites were polymorphic and 29 were monomorphic within the analyzed isolates. T. solium tapeworms were classified into two genetic groups that correlated with the North/South geographic origin of the parasites.
Conclusions/significance:
The availability of draft genomes for T. solium represents a significant step towards the understanding the biology of the parasite. We report here a set of T. solium polymorphic microsatellite markers that appear promising for genetic epidemiology studies.
Las especies del género Taenia pertenecen a la clase Cestoda, orden Ciclophyllidea y a la familia Taeniidae. Sus formas adultas se desarrollan en el intestino del ser humano que actúa como único hospedador definitivo, y los estadios larvarios o cisticercos en los tejidos de los animales (cerdos, jabalíes y bóvidos), o el hombre. La teniasis humana se produce como consecuencia de la parasitación intestinal por especies del género Taenia. Las especies más comunes son Taenia solium y Taenia saginata, pero existe otra especie, Taenia saginata asiatica, que ha sido descrita de forma relativamente reciente (1991-1998). Mientras que las dos primeras tienen una distribución cosmopolita, la de T. saginata asiatica se circunscribe a Taiwan, Corea, Tailandia, Indonesia, China, Malasia y las Filipinas, con casos esporádicos en algunos países como España. La ingestión de huevos de T. saginata saginata y T. solium/T.saginata asiatica deriva en cisticercosis bovina y porcina, respectivamente. Los huevos de T. solium también pueden infectar a humanos dando lugar a la cisticercosis humana. No está claro que los huevos de T. saginata asiatica puedan infectar al hombre, aunque se piensa que dicha especie podría ser responsable de algunos casos de cisticercosis humana descritos en Asia. La parasitación por el género Taenia es una zoonosis cuyas tasas de prevalencia varían en función de diversos factores socio-económicos y culturales. El comportamiento humano resulta fundamental para su persistencia, ya que la contaminación con heces humanas de los terrenos posibilita la infección de los animales, y el hábito de ingerir carne cruda o poco cocinada cierra el ciclo permitiendo la infección humana por tenias adultas. La teniasis humana constituye un problema de salud pública que no afecta sólo a áreas endémicas, puesto que se ha observado un número creciente de casos en otras zonas geográficas.
Parasitosis due to taenia is a disease with low incidence in our setting, it predominating in the rural area in those who eat undercooked meat and animal origin food such as pork or beef.
The most frequent symptoms that they can cause are gastrointestinal. However, urticarial reactions, headache and anorexia may be present. Complications such as appendicitis, obstruction or intestinal perforation and muscle or brain involvement are unusual.
A case of parasitosis due to Taenia Saginata whose clinical manifestation initially suggested a serious neurological condition is presented.
Species-specific identification of human tapeworm infections is important for public health purposes, because prompt identification of Taenia solium carriers may prevent further human cysticercosis infections (a major cause of acquired epilepsy). Two practical methods for the differentiation of cestode proglottids, (i) routine embedding, sectioning, and hematoxylin-eosin (HE) staining and (ii) PCR with restriction enzyme analysis (PCR-REA), were tested on samples from 40 individuals infected with T. solium (n = 34) or Taenia saginata (n = 6). Microscopic examination of HE staining of sections from 24 cases, in which conserved proglottids were recovered, clearly revealed differences in the number of uterine branches. Distinct restriction patterns for T. solium and T. saginata were observed when the PCR products containing the ribosomal 5.8S gene plus internal transcribed spacer regions were digested with either AluI, DdeI, or MboI. Both HE histology and PCR-REA are useful techniques for differentiating T. solium from T. saginata. Importantly, both techniques can be used in zones of endemicity. HE histology is inexpensive and is currently available in most regions of endemicity, and PCR-REA can be performed in most hospital centers already performing PCR without additional equipment or the use of radioactive material.
The prevalence and characteristics of human taeniasis/cysticercosis and porcine cysticercosis were assessed in an endemic area of the Peruvian highlands. Individuals from 10 communities had stool examinations (N = 2,951) and serologic testing for Taenia solium antibodies (N = 2,583). The total porcine population present (N = 703) was also examined by serology. Cysticercosis is hyperendemic in this area and is associated with an important number of seizure cases. Human seroprevalence by village ranged from 7.1-26.9% (mean, 13.9%). Seroprevalence was higher among individuals with a history of seizures but not in those reporting a history of headache or intestinal taeniasis. Prevalence of taeniasis ranged from 0-6.7% (median, 2.5%). Coproantigen detection found 2.4 times more taeniasis cases than did microscopy (direct and after concentration). Age distribution for taeniasis showed a peak at younger ages than for seroprevalence. Porcine seroprevalence ranged from 42-75%. Random effects logistic regression models for human seropositivity demonstrated both in-house clustering of cases and a large increase in risk associated with a tapeworm carrier in the house. Besides confirming the close relationship between taeniasis and cysticercosis cases, this large-scale field study demonstrated early age of tapeworm and cysticercosis infections in humans, and short duration of taeniasis infections.
An epidemiological study was conducted in a Honduran rural community in 1991, to determine the local prevalence and associated risk factors of Taenia infection. The seroprevalence of anti-cysticercus antibodies, investigated by ELISA (N = 526), was found to be 30%. The prevalence of intestinal infections with Taenia and other parasites was investigated, by formol-ether concentration of three stool samples from each subject (N = 536). Almost all (96%) of the subjects carried at least one of the 17 species of intestinal parasite identified, 11 (2%) of them (nine of them female) being found to be infected with Taenia spp. When nine of these 11 were given niclosamide, four expelled Taenia segments, all of which were identified as T. solium after carmine staining. Risk factors associated with seropositivity were earthen floor, overcrowding, previous taeniasis and living in the same household as a person reporting previous taeniasis. Four years later (1995), a follow-up study in a sub-sample of the previously studied population revealed that 34% of the subjects were seropositive for anti-Taenia solium antibodies (as determined by a cysticercosis-specific, enzyme-linked, immunoelectrotransfer, blot assay) and that 1.5% had taeniasis. Taeniasis and cysticercosis therefore appear to be important public-health problems in rural areas of Honduras, as they are in other countries of Latin America. Large-scale studies need to be conducted to facilitate the design of programmes to control these diseases.
The larval stage of the pork tapeworm (Taenia solium) infects the human nervous system, causing neurocysticercosis. This disease is one of the main causes of epileptic seizures in many less developed countries and is also increasingly seen in more developed countries because of immigration from endemic areas. Little information is available on the natural evolution of taeniasis or cysticercosis. Available therapeutic measures include steroids, treatments for symptoms, surgery, and, more controversially, antiparasitic drugs to kill brain parasites. Efforts to control and eliminate this disease are underway through antiparasitic treatment of endemic populations, development of pig vaccines, and other measures.
Instituto de Ciencias Neurológicas, Jiron Ancash 1271
- Correspondence
- H Hector
- Cysticercosis Garcia
- Unit
Correspondence to: Dr Hector H Garcia, Cysticercosis Unit, Instituto
de Ciencias Neurológicas, Jiron Ancash 1271, Barrios Altos, Lima 1,
Peru
(e-mail: hgarcia@jhsph.edu)
Universidad Peruana Cayetano Heredia San Martin de Porras
- C Jeri Bsc
- R Gilman
- Md Msc
- H Garcia
- Md Gilman
- M Ramirez
- R Nazerali
Department of Microbiology, School of Sciences (C Jeri BSc,
R H Gilman MD, H Mayta MSc H H Garcia MD), and School of Public
Health and Administration (A G Lescano MHS), Universidad Peruana
Cayetano Heredia San Martin de Porras, Lima, Peru; Asociación
Benéfica PRISMA, San Miguel, Lima, Peru (R H Gilman MD,
M E Ramirez MD, R Nazerali); Naval Medical Research Centre
Detachment, Global Emerging Infections System, Lima, Peru
(A G Lescano MHS); School of Veterinary Medicine, Universidad
Nacional Mayor de San Marcos, Lima, Peru (A E Gonzalez PhD); and
Cysticercosis Unit, Instituto de Ciencias Neurológicas, Jiron
Ancash 1271, Barrios Altos, Lima 1, Peru (H H Garcia MD)
The sponsors had no role in study design, data collection, data analysis, data interpretation
- Wellcome From The
- Trust
from the Wellcome Trust. The sponsors had no role in study design, data
collection, data analysis, data interpretation, or writing of the report.