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The intestinal protozoan Giardia duodenalis is a widespread opportunistic parasite of humans and animals. This parasite inhabits the upper part of the small intestine and has a direct life cycle. After ingestion of cysts, which are the infective stage, the trophozoites emerge from the cysts in the duodenum and attach to the small intestinal mucosa...
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... was credited with the dis- covery in 1859 of the flagellate Giardia. The name lamblia was given to the species by Blanchard in 1888 (121). Giardia, a flagellated protozoan, inhabits the upper part of the small intestine of its host and has a direct life cycle. After the host ingests cysts, which are the infective stage, the trophozoites ( Fig. 1) emerge from the cysts in the duodenum and attach to the small intestinal mucosa. They undergo mitotic division in the intracellular lumen; some will encyst to protect themselves and will be eliminated from the host in the feces. Cysts can survive for 3 months in water at 4°C (120,121). They are transmitted to a new host through ...
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... were isolated from mammal, bird, and amphibian hosts (105). Initially, assignment of a species name to Giardia was based on the animal host species from which the organism was isolated. Filice (66) rejected this concept of host specificity and proposed to use the morphology of the tropho- zoite microtubular organelles known as the median body ( Fig. 1) to classify species into three groups: (i) the amphibian group (G. agilis), which has a long teardrop-shaped median body; (ii) the rodent and bird group (G. muris), which has two small, rounded median bodies; and (iii) the human group (G. duo- denalis lamblia intestinalis), in which the single or double median bodies resemble the claw ...
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... species into three groups: (i) the amphibian group (G. agilis), which has a long teardrop-shaped median body; (ii) the rodent and bird group (G. muris), which has two small, rounded median bodies; and (iii) the human group (G. duo- denalis lamblia intestinalis), in which the single or double median bodies resemble the claw of a claw hammer (Fig. 1). Organisms of the duodenalis group have been described not only in humans but also in other mammals, birds, and ...
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... of caplike structures described by Erlandsen et al. (57). These large se- cretory vesicles form only during encystation, and they trans- port cyst antigens (Fig. 9) to the nascent wall (118). In contrast, only TSA 417 was found on the outer surface of the plasma- lemma of trophozoites, encysting cells, and underlying the walls of many cysts ( Fig. 9 and 10). As encystation progresses (Fig. 10), TSA 417 disappears from the plasmalemma and its level in the lysosome-like peripheral vesicles and other large cytoplasmic vesicles is increased ...
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... et al. (57). These large se- cretory vesicles form only during encystation, and they trans- port cyst antigens (Fig. 9) to the nascent wall (118). In contrast, only TSA 417 was found on the outer surface of the plasma- lemma of trophozoites, encysting cells, and underlying the walls of many cysts ( Fig. 9 and 10). As encystation progresses (Fig. 10), TSA 417 disappears from the plasmalemma and its level in the lysosome-like peripheral vesicles and other large cytoplasmic vesicles is increased ...
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Giardiasis is a neglected parasitic disease that affects primarily children, in whom it delays physical
and mental development. The pathophysiology of giardiasis in not well understood, and most reports have identified Giardia intestinalis trophozoites only in the lumen and on the brush border of the small intestine. We identified Giardia trophozoi...
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... The main challenge with antibody-based detection methods for the diagnosis of giardiasis is that the antibody remains for a relatively long time after spontaneous recovery or drug treatment (4,(16)(17)(18). Therefore, the presence and detection of antibodies in the human serum do not indicate an active Giardia infection. ...
Background: We aimed to present a systematic review and meta-analysis of studies that used antigen-based assays for the diagnosis of human giardiasis.
Methods: All the related published literature cited within PubMed, ISI web of science, Google Scholar, Embase, and Scopus, were searched up to December 2021. The search terms, both as MeSH terms and text words, were “Giardia”, “Giardia lamblia”, “Giardia intestinalis", "giardiasis", combined with "diagnosis", "antigen detection", serodiagnosis, or serological diagnosis. The required data was extracted from the papers. Pooled estimates of sensitivity and specificity were obtained and forest plots and summary receiver operating characteristics (SROC) plots were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).
Results: The search of databases found 1683 papers, of which 46 articles fulfilled our eligibility criteria. The sensitivity of antigen-based methods for the diagnosis of human giardiasis ranged from 45% (95% CI: 31-59%) to 100% (95% CI: 100-100%) and the pooled estimate of sensitivity was 92% (95% CI: 90-93%). The pooled estimated specificity was 97% (95% CI: 96-98%), ranged from 81% (95% CI: 68-89%) to 100% (95% CI: 98-100%). The summary estimate of PPV and NPV were 92 % (95% CI: 90-93%) and 97% (95% CI: 96-98%) respectively. Comparing the performance of the antigen detection assays by region revealed a significant difference in the assay's performances in different regions of the world.
Conclusion: The antigen-based detection methods have acceptable and satisfactory performance in the diagnosis of human giardiasis. The task ahead is to identify more specific target antigens and design simpler, cheaper, and more sensitive methods for the diagnosis of this common worldwide-distributed parasitic infection.
... This observation was similar to studies recorded in Brazil (18) and Kenya (21). The probable explanation for the age-dependent decline rate seen has been attributed to the anti-Giardia immunity (22,23) developed during growing years. Furthermore, greater hygiene practices may have been developed, making it easier to avoid catching this infection (24). ...
Introduction and Aim: Intestinal parasite infections among children are a worldwide problem, particularly in developing countries. Intestinal parasitic infections can lead to several health issues including growth and physical development in children. This investigation aimed to determine the prevalence of intestinal parasites in school children residing in Al Hawija, Kirkuk. Materials and Methods: This study, undertaken between May 2021 and October 2022, involved 247 children aged between 2 and 13 years residing at Al Hawija, Kirkuk City. Stools samples collected from these children were studied for intestinal parasitic infections. Results: Of the 247 children 194 (78.6%) were seen to harbor intestinal parasites. Among these, the prevalence of protozoal and helminthic infection was observed to be 152 (61.5%) and 42 (17%) respectively. Among the protozoans, the highest prevalence was seen for Entamoeba histolytica (61.8%), followed by Giardia lamblia (30.9%) and Entamoeba coli (7.2%). Similarly, among helminthes, the highest infection was by Ascaris lumbricoidis (45.2%), followed by Enterobius vermicularis (21.4%), Trichuris trichura (11.9%), Hymenolepis nana (11.9%) and Taenia spp. (9.5%). The prevalence for these parasitic infections was observed to be highest in children aged 2-5 years. Conclusion: Children aged between 2- 5 years are prone to parasitic infections in comparison to children between 10-13 years.
... Indirect morbidity is particularly important in children with parasitic infections, ranging from malnutrition, anemia, growth retardation, irritability and cognitive impairment to increase susceptibility to other infections and acute complications (1), protein energy malnutrition is another complication of parasitic infection which is common problem in populations with low socioeconomic status and low level of public health sanitation (2). Attachment of a large number of G. lamblia to intestinal mucosa may exert an irritative, mechanical, or possibly a toxic action on the intestinal mucosa may lead to shortening and blunting of the villi, thus interfering with intestinal absorption of nutrients and producing malabsorption syndrome (3). E. histolytica have numerous virulence factors such as proteinases, lectin and amoebapore for digestion and penetration of intestinal mucosa leading to diarrhea as well as malabsorption of nutrients and minerals (4). ...
... As illustrated in table (2), serum zinc concentration mean±SE µg/dl of G. lamblia 79±15 and E. histolytica 78±13 and infected children were significantly lower than non-infected 96±7 at (p<0.05). See figure (3)(4)(5)(6). Serum copper concentration (mean±ES) µg/dl of G. lamblia infected group 110±19 µg/dl was not significantly different from non-infected 125±11 µg/dl, while E. hitolytica infected children 65±7 µg/dl were significantly lower than noninfected at (p<0.01). The serum iron levels decreased significantly (p<0.05) in children with giardiasis 54±6 µg/dl and amoebiasis 68±11 compared to the non-infected group 87±10 µg/dl. ...
Giardia lamblia is a flagellate protozoon which causes giardiasis. The infection is limited to the small intestine and/ or the biliary tract. It may produce a wide range of gastrointestinal symptoms especially in children; which include vomiting, flatulence, diarrhea and malabsorption syndrome. Entamoeba histolytica causes amoebiasis in human beings which is an infection of the large intestine; it may invade the host tissues. It may produce acute amoebic dysentery which is accompanied with blood, mucus and tenesmus; chronic and asymptomatic amoebiasis or extra-intestinal amoebiasis. This study was carried out from second of May to thirties of November 2008 to show the relationship between Giardia lamblia and Entamoeba histolytica infections with some biochemical parameters and anthropometric measurements among 348 children aged 2-13 years old in Kalar General Hospital. Stool examination was done by direct method using normal saline and lugols iodine solution. Biochemical parameters (total protein, albumin, globulin, zinc, copper, and iron were estimated by spectrometry. The nutritional status were determined by measuring weight for age (WFA), weight for height (WFH) and height for age (HFA) according to National Center for Health Statistics (NCHS). The overall prevalence of infections was 48%. The infection rate of E. histolytica 31.6% was higher than G. lamblia 16.37%. Total serum protein and albumin concentrations were decreased significanly in G. lamblia (7.15 mg/dl, 4.91 mg/dl) and E. histolytica (6.48mg/dl, 4.76 mg/dl) infected children compared to non-infected (7.49 mg/dl, 5.02mg/dl), while total globulin concentration increased significantly in G. lamblia (3.41 mg/dl) and decreased slightly in E. histolytica (2.22mg/dl) infected children compared to non-infected (2.56 gm/dl) ones. Serum zinc and iron element concentrations decreased significantly in G. lamblia (79µg/dl, 54µg/dl) and E. histolyrtica (78 µg/dl, 68 µg/dl) infections compared to non-infected (96µg/dl, 87µg/dl) respectively, while copper level decreased slightly in G. lamblia (110µg/dl) and significantly in E. histolytica (65 µg/dl) infections in comparison to non-infected group (125µg/dl). G. lamblia and E. histolytica infections were more prevalent in underweight children (low WFA), and stunted children (low HFA), whereas in wasted children (WFH) had no relation with both infections.
... An Indian study by Yadav et al. showed a total 9.8 % cases of refractory giardiasis [1]. The rise in giardiasis susceptibility and the rate of therapeutic failure have traditionally been attributed to B cell dysfunction [8], but more recent research suggests that T cells may also play a role in these outcomes. In an adult mouse model, T cells were required to control Giardia infections [9], and evidence suggests that T cell dysfunction occurs in patients with common variable hypogammaglobulinaemia [10][11][12]. ...
Giardiasis is an infection of the small intestine caused by the protozoan parasite Giardia intestinalis and one of the most common parasitic intestinal diseases in humans worldwide. It mainly manifests as a self-limited illness in the case of immunocompetent patients and usually does not require treatment. However, immunodeficiency is a risk factor for the onset of severe Giardia infection. In this report, a case of recurrent giardiasis refractory to nitroimidazole therapy is presented. A 7-year-old male patient with steroid-resistant nephrotic syndrome came to our hospital because of chronic diarrhoea. The patient was on long-term immunosuppressive therapy. Microscopic examination of stool showed a significant number of trophozoites and cysts of G. intestinalis . Treatment with metronidazole for longer duration than recommended has failed to clear the parasite in the present case.
... Although current knowledge regarding the mechanisms of immunity to Giardia is limited, several studies have produced significant advances in the understanding of innate and adaptive host responses against the parasite (Faubert, 2000). ...
... The mucus layer on the intestine surface and peristaltic movements constitute mechanical barriers to Giardia attachment. Antimicrobial peptides (AMP) released by paneth and other cells can kill trophozoites (Faubert, 2000). ...
... Mast cells release pro-inflammatory cytokines such as IL-6; mast cell degranulation promotes peristalsis. Gut epithelial and immune cells produce nitric oxide (NO), which has a cytostatic effect on Giardia trophozoites, inhibits excystation/encystation processes and contributes to peristalsis (Faubert, 2000). ...
Giardiasis is the most common waterborne parasitic intestinal infection ofboth animals and humans worldwide, and it leads to significant morbidity and mortality in animals, particularly in young aged group like calves in the developing and developed world. It is a zoonotic infectious disease where animals are considered as sources of infection for humans through consumption of water and food contaminated with cysts of Giardia. Giardia species differ significantly in host range, with G. duodenalis having the broadest host range and greatest public health significance. Giardia duodenalis has eight different assemblages A through H. The disease Causes gastro intestinal disturbance, gall bladder colic and jaundice. Malabsorption and maldigestion mainly result from a diffuse shortening of epithelial microvillus. Giardia duodenalis (synonyms intestinalis, lamblia) is a flagellate binucleated protozoan, and it has two morphological forms: cysts and trophozoites. The life cycle of Giardia is direct, and the infective stage of the parasite, the cyst, is encysted when released into the feces and is immediately infectious. Trophozoites are pear-shaped, binucleate, multi-flagellated parasite forms and are the disease causing stage and colonize the upper small intestine, where they adhere to the epithelial surface and proliferate by binary fission. Infected animals, contaminated water and feed are main sources of infection. Age of animals, season of the year, area, housing, feeding, management practices are usually considered as risk factors for the occurrence of giardiasis. The infection can be transmitted by the fecal-oral route, or through contaminated food and water. To survive within the intestine, Giardia undergoes antigenic variation and few virulent factors have been identified to be responsible for the infection. These include ventral adhesive disc proteins and surface lectins, the four pairs of flagella which allow for movement and variant surface proteins. The clearance of Giardia from a host requires both innate and adaptive immunity effector mechanisms. The infection can be diagnosed by examining fecal specimens using different coproscopic techniques, serological tests and by molecular analysis. Restricting animals from surface water during periods of high cyst shedding may reduce watershed contamination. Health education on personal and environmental hygiene would help in reducing the occurrence of the infection. This review work tries to gather information on giardiasis of domestic animals with respect to its epidemiology, host immune responses, pathophysiology, distribution and its public health importance.
... Giardia duodenalis and E. histolytica infections usually cause diarrhea or dysentery and a complex of symptoms such as stomach ache, cramps, bloating, tenderness, nausea, and weight loss [30]. Giardia duodenalis generally affects the small intestine (mainly the duodenum), leading to nutritional deficiencies and significant morbidity and mortality, especially among children, the elderly, travelers in developing countries and immunocompromised patients [31,32]. Entamoeba histolytica infects the large intestine, and amoebic abscesses from the large intestine can spread to the liver, pleura, pericardium, and brain [33]. ...
Despite advances in modern human and veterinary medicine, gastrointestinal (GI) parasitic infections remain a significant health issue worldwide, mainly in developing countries. Increasing evidence of the multi-drug resistance of these parasites and the side effects of currently available synthetic drugs have led to increased research on alternative medicines to treat parasitic infections. The exploration of potential botanical antiparasitics, which are inexpensive and abundant, may be a promising alternative in this context. This study summarizes the in vitro/in vivo antiparasitic efficacy of different medicinal plants and their components against GI parasites. Published literature from 1990–2020 was retrieved from Google Scholar, Web of Science, PubMed and Scopus. A total of 68 plant species belonging to 32 families have been evaluated as antiparasitic agents against GI parasites worldwide. The majority of studies (70%) were conducted in vitro. Most plants were from the Fabaceae family (53%, n = 18). Methanol (37%, n = 35) was the most used solvent. Leaf (22%, n = 16) was the most used plant part, followed by seed and rhizome (each 12%, n = 9). These studies suggest that herbal medicines hold a great scope for new drug discoveries against parasitic diseases and that the derivatives of these plants are useful structures for drug synthesis and bioactivity optimization.
... The reason for the rise in these age groups may be attributed to the lack of effective immunity against various pathogenic microorganisms and because this age group is relatively less resistant to them. There are factors such as poor hygiene, low socioeconomic status and environmental conditions (Faubert, 2000) In addition, children are more in contact with the land, polluted and share things with each other, all of these factors may be responsible for the increased incidence at this age (Al Kahfaji et al., 2019) ...
... Infections usually associated with poor personal hygiene, poor water quality and over crowding. Disease variabilityis related with multiple factors such as host age and gender, level of host immunityand nutrition, strain genotype, infective dose and possibly co-infection [13,14]. ...
The current study aimed to determine the total rate of giardiasis infection in humans including infected rate with or without symptoms. Also, the infection rate according to gender was under consideration. The frequency distribution for ABO and Rh blood groups was assessed to seek for the possible relationships with giardias is. The current study was carried in the Microbiology laboratory of Al-Yarmouk teaching hospital/Baghdad/Iraq for the period from the 1 st of March till the end of August /2016.The study include of 532 patients (318 male and 214 female) aged 20-45 years old to detect the existence of Giardia lambliain stool samples by microscopic examination using flotation method and staining method (Lugol's iodine and Chromo trope 2R).The blood samples were collected from 130 patients for the purpose of measuring the concentration of IgG and IgM antibodies in serum using Enzyme Linked Immuno sorbent Assay(ELISA)and to determine blood type using ABO and Rh blood group system. The results revealed that the total infection rate was 32.89% with no significant differences according to gender as the higher rate was recorded for males 18.79% compared with females14.09%. For the infection rate according to state, the symptomatic patients recorded 69.7% (59.8% for males and 40.1% for females)while, asymptomatic patients recorded 30.2% (50.9% for males and 49.05% for females),no significant association p=0.27 between gender and the state was observed while, significant differences P<0.0001 for the total symptomatic and the total of asymptomatic was recorded. The mean concentration of IgM and IgG showed significant differences between infected (symptomatic, asymptomatic) and non-infected patients for each of males and females. The overall blood-group frequencies for symptomatic were A(40%) > B (26%)> O (24%) > AB (10%) and for asymptomatic were O (42%) > A (24%) > B (22%) > AB (12%) also higher percentage was observed for Rh positive 98%,96% for symptomatic and asymptomatic respectively, no significant association between ABO P=0.19, Rh P= 1.04blood group and the state of infection was detected. a significant correlation (P<0.01) showed between the total infection rate and the distribution in each of blood group (0.77)and Rh test (0.79). Also a significant correlation (P<0.01) (0.69) and(0.59) was found between ABO and each of symptomatic and asymptomatic infections respectively. The correlations of Rh with symptomatic (0.82) and asymptomatic (0.54) were significant (P<0.01). The overall finding show edhighly prevalent of G. lamblia mainly in males. There was a correlation between human blood and Rh types with giardiasis as most blood type A individuals were symptomatic patients while most blood type O were asymptomatic.
... The main challenge with antibody-based detection methods for the diagnosis of giardiasis is that the antibody remains for a relatively long time after spontaneous recovery or drug treatment (4,(16)(17)(18). Therefore, the presence and detection of antibodies in the human serum do not indicate an active Giardia infection. ...
Background: We aimed to present a systematic review and meta-analysis of studies that used antigen-based assays for the diagnosis of human giardiasis. Methods: All the related published literature cited within PubMed, ISI web of science, Google Scholar, Embase, and Scopus, were searched up to December 2021. The search terms, both as MeSH terms and text words, were “Giardia”, “Giardia lamblia”, “Giardia intestinalis", "giardiasis", combined with "diagnosis", "antigen detection", serodiagnosis, or serological diagnosis. The required data was extracted from the papers. Pooled estimates of sensitivity and specificity were obtained and forest plots and summary receiver operating characteristics (SROC) plots were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: The search of databases found 1683 papers, of which 46 articles fulfilled our eligibility criteria. The sensitivity of antigen-based methods for the diagnosis of human giardiasis ranged from 45% (95% CI: 31-59%) to 100% (95% CI: 100-100%) and the pooled estimate of sensitivity was 92% (95% CI: 90-93%). The pooled estimated specificity was 97% (95% CI: 96-98%), ranged from 81% (95% CI: 68-89%) to 100% (95% CI: 98-100%). The summary estimate of PPV and NPV were 92 % (95% CI: 90-93%) and 97% (95% CI: 96-98%) respectively. Comparing the performance of the antigen detection assays by region revealed a significant difference in the assay's performances in different regions of the world. Conclusion: The antigen-based detection methods have acceptable and satisfactory performance in the diagnosis of human giardiasis. The task ahead is to identify more specific target antigens and design simpler, cheaper, and more sensitive methods for the diagnosis of this common worldwide-distributed parasitic infection.
... Even though Giardia infection is usually self-limiting in immunocompetent persons, probably due to the effective host immune response against infection, resistant or chronic giardiasis can develop despite a healthy immune system (Faubert 2000). Parasite clearance in giardiasis requires a complex interaction between innate and adaptive immune responses. ...
Giardiasis, a parasitic infection of the gastrointestinal tract, is prevalent worldwide. The integrity of the intestinal epithelial barrier plays an important defensive role in giardiasis, and as Oral supplementation with prebiotics and probiotics is known to reinforce the intestinal barrier in many gastrointestinal diseases, this study assessed the effects of prebiotic and probiotic supplementation in giardiasis and compared the results with those obtained after nitazoxanide therapy. Swiss albino male lab-bred mice (n = 50) were divided into three major groups; Group I (control group), i.e., negative (noninfected nontreated) and positive controls (infected nontreated); Group II (preventive group), in which mice were provided prebiotic, probiotic, or a combination for 7 days before of infection, and Group III (therapy group), in which mice were administered prebiotic, probiotic, combined supplements and nitazoxanide from day 12 post-infection. The assessment was achieved through Giardia cyst count, histopathological examination and ultrastructure study. Also, Serological and immunohistochemical parameters were done to evaluate the modulation of IgA levels. Oral supplementation with prebiotic and probiotic, either before or after infection (in preventive or therapy groups respectively) resulted in a significant reduction in Giardia cyst shedding. Remarkable histological and ultrastructure improvement in the intestinal changes, along with a significant increase in the serological and immunohistochemical IgA levels, were seen in mice provided combined supplements and nitazoxanide (in therapy group). Thus, our results indicate that combined prebiotic and probiotic supplementation has promising anti-Giardia activity and that it can restore intestinal structures and modulate IgA response, apart from providing synergistic effects when added to nitazoxanide.
