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Morphology of Triatoma rubrofasciata.a An adult male (left) and female (right). b Morphological characteristics of T. rubrofasciata: 1, there is an orange-red margin along the outer edge of the abdomen as well as the side of the pronotum; 2, the pronotum is dark brown or black and conspicuously granulose; 3, the scutellum is wide at the base and tapers to the tip; 4, the head is uniformly dark and heavily granulose dorsally; 5, the 1st segment of antenna surpasses the head
Source publication
Background:
Triatomines are natural vectors of Chagas disease and are mainly prevalent in the Americas. In China, previous data from decades ago showed that there were two species of triatomine bugs, Triatoma rubrofasciata and T. sinica. However, the distribution, genetic characteristics and public health implications of triatomines in China are s...
Similar publications
Innovative approaches used to combat Chagas disease transmission tend to combine a set of comprehensive efforts to understand the ecology of local vectors. In this work we identified molecularly the blood meal of 181 Triatoma brasiliensis, distributed in 18 populations (8 sylvatic and 10 peridomestic), which were collected across a range of 240 km...
Citations
... atrata) were recognized [19]. Previous studies revealed that Tr. rubrofasciata is widely distributed in southern China (e.g. in Guangdong Province, Hainan Province and the Guangxi Zhuang Autonomous Region), where people are reportedly bitten [20,21]. In this study, flagellates were found in field-captured Tr. rubrofasciata. ...
... After all, Tr. rubrofasciata is the only globally distributed triatomine, and its prevalence has been reported to increase significantly in several Asian countries [33,34]. Moreover, previous investigations have shown a rising number of reports of Tr. rubrofasciata bites in humans across regions of China, which is becoming a public health problem because it can also cause severe anaphylactic reactions [17,20]. In our study, Chinese T. conorhini was not transovarially transmitted in the Tr. ...
... This indicated that Tr. rubrofasciata is a vector for T. conorhini. Furthermore, this is supported by a paper describing a high number of Tr. rubrofasciata found near chicken coops [20]. Therefore, future work should investigate the possibility of chickens as reservoir hosts. ...
Background
Triatomines (kissing bugs) are natural vectors of trypanosomes, which are single-celled parasitic protozoans, such as Trypanosoma cruzi, T. conorhini and T. rangeli. The understanding of the transmission cycle of T. conorhini and Triatoma rubrofasciata in China is not fully known.
Methods
The parasites in the faeces and intestinal contents of the Tr. rubrofasciata were collected, and morphology indices were measured under a microscope to determine the species. DNA was extracted from the samples, and fragments of 18S rRNA, heat shock protein 70 (HSP70) and glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) were amplified and sequenced. The obtained sequences were then identified using the BLAST search engine, followed by several phylogenetic analyses. Finally, laboratory infections were conducted to test whether Tr. rubrofasciata transmit the parasite to rats (or mice) through bites. Moreover, 135 Tr. rubrofasciata samples were collected from the Guangxi region and were used in assays to investigate the prevalence of trypanosome infection.
Results
Trypanosoma sp. were found in the faeces and intestinal contents of Tr. rubrofasciata, which were collected in the Guangxi region of southern China and mostly exhibited characteristics typical of epimastigotes, such as the presence of a nucleus, a free flagellum and a kinetoplast. The body length ranged from 6.3 to 33.9 µm, the flagellum length ranged from 8.7 to 29.8 µm, the nucleus index was 0.6 and the kinetoplast length was −4.6. BLAST analysis revealed that the 18S rRNA, HSP70 and gGAPDH sequences of Trypanosoma sp. exhibited the highest degree of similarity with those of T. conorhini (99.7%, 99.0% and 99.0%, respectively) and formed a well-supported clade close to T. conorhini and T. vespertilionis but were distinct from those of T. rangeli and T. cruzi. Laboratory experiments revealed that both rats and mice developed low parasitaemia after inoculation with Trypanosoma sp. and laboratory-fed Tr. rubrofasciata became infected after feeding on trypanosome-positive rats and mice. However, the infected Tr. rubrofasciata did not transmit Trypanosoma sp. to their offspring. Moreover, our investigation revealed a high prevalence of Trypanosoma sp. infection in Tr. rubrofasciata, with up to 36.3% of specimens tested in the field being infected.
Conclusions
Our study is the first to provide a solid record of T. conorhini from Tr. rubrofasciata in China with morphological and molecular evidence. This Chinese T. conorhini is unlikely to have spread through transovarial transmission in Tr. rubrofasciata, but instead, it is more likely that the parasite is transmitted between Tr. rubrofasciata and mice (or rats). However, there was a high prevalence of T. conorhini in the Tr. rubrofasciata from our collection sites and numerous human cases of Tr. rubrofasciata bites were recorded. Moreover, whether these T. conorhini strains are pathogenic to humans has not been investigated.
Graphical Abstract
... Trypanosoma cruzi is mainly transmitted by kissing bugs, hematophagous insects belonging to the subfamily Triatominae. There are 18 genera and 154 species of triatomine bugs (Shi et al., 2020). Triatomines inhabit in tropical and subtropical areas of the Americas, from Southern United States to Argentina, Asia, Africa, and Oceania (Shi et al., 2020;Schijman et al., 2022;Zhao et al., 2023). ...
... There are 18 genera and 154 species of triatomine bugs (Shi et al., 2020). Triatomines inhabit in tropical and subtropical areas of the Americas, from Southern United States to Argentina, Asia, Africa, and Oceania (Shi et al., 2020;Schijman et al., 2022;Zhao et al., 2023). However, vector transmission only occurs in the Americas. ...
Background
Chagas disease (CD), caused by Trypanosoma cruzi, is a global health concern with expanding geographical reach. Despite improved and accessible test methods, diagnosing CD in its various phases remains complex. The existence of clinical scenarios, including immunosuppressed patients, transplant-related CD reactivation, transfusion-associated cases, and orally transmitted acute infections, adds to the diagnostic challenge. No singular gold standard test exists for all phases, and recommendations from PAHO and the CDC advocate for the use of two serological methods for chronic CD diagnosis, while molecular methods or direct parasite detection are suggested for the acute phase. Given the complexity in the diagnostic landscape of CD, the goal of this scoping review is to characterize available diagnostic tests for CD in the clinical laboratory.
Methods
A literature search in PubMed was conducted on studies related to In vitro diagnosis (IVD) in humans published in English, Spanish, or Portuguese language as of 28 August 2023, and extended backward with no predefined time frame. Studies underwent title and abstract screening, followed by full-text review. Studies included were classified based on the diagnostic method used. Test methods were grouped as serological, molecular, and other methods. Performance, availability, and regulatory status were also characterized.
Results
Out of 85 studies included in the final review, 115 different tests were identified. These tests comprised 89 serological test types, 21 molecular test types, and 5 other test methods. Predominant serological tests included ELISA (38 studies, 44.70%), Rapid tests (19 studies, 22.35%), and chemiluminescence (10 studies, 11.76%). Among molecular tests, Polymerase Chain Reaction (PCR) assays were notable. Twenty-eight tests were approved globally for IVD or donor testing, all being serological methods. Molecular assays lacked approval for IVD in the United States, with only European and Colombian regulatory acceptance.
Discussion and conclusion
Serological tests, specifically ELISAs, remain the most used and commercially available diagnostic methods. This makes sense considering that most Chagas disease diagnoses occur in the chronic phase and that the WHO gold standard relies on 2 serological tests to establish the diagnosis of chronic Chagas. ELISAs are feasible and relatively low-cost, with good performance with sensitivities ranging between 77.4% and 100%, and with specificities ranging between 84.2% and 100%. Molecular methods allow the detection of specific variants but rely on the parasite’s presence, which limits their utility to parasitemia levels. Depending on the PCR method and the phase of the disease, the sensitivity ranged from 58.88 to 100% while the mean specificity ranged from 68.8% to 100%. Despite their performance, molecular testing remains mostly unavailable for IVD use. Only 3 molecular tests are approved for IVD, which are available only in Europe. Six commercial serological assays approved by the FDA are available for blood and organ donor screening. Currently, there are no guidelines for testing CD oral outbreaks. Although more evidence is needed on how testing methods should be used in special clinical scenarios, a comprehensive approach of clinical assessment and diagnostics tests, including not IVD methods, is required for an accurate CD diagnosis.
... rubrofasciata and T. sinica) have been recorded in 30 Chinese cities [7]; of these, T. rubrofasciata was the dominant species. It has also been widely reported in tropical and subtropical areas of southern China, including Guangdong, Fujian, Guangxi, Hainan, and Taiwan Provinces [7,8]. ...
... After DNA extraction, the species of bugs was confirmed by amplifying and sequencing the cytb gene of randomly selected samples [8]. All the DNA samples were screened for the presence of Anaplasmataceae bacteria (including Ehrlichia spp., Anaplasma spp., and Neoehrlichia spp.), Rickettsia spp., Bartonella spp., and Coxiella spp. ...
Background:
The blood-feeding behavior of kissing bugs (subfamily Triatominae, family Reduviidae, order Hemiptera) means they are potential vectors of multiple humans pathogens. However, investigations of vector-borne pathogens harbored by kissing bugs are rare.
Methods:
In the current study, 22 adult kissing bugs (Triatoma rubrofasciata) were captured in Huizhou City, Guangdong Province, south China. The presence of vector-borne pathogens in the kissing bugs was tested, and the genetic diversity of these potential pathogens was investigated.
Results:
All the kissing bugs were negative for Anaplasmataceae bacteria, Rickettsia, and Coxiella. Bartonella DNA was detected in 36.4% (8/22) of the kissing bugs. The sequences of the Bartonella gltA genes divided into two clades in a phylogenetic tree, with close relationships to B. tribocorum and uncultured Bartonella sp. clone MYR-283, respectively. All the groEL sequences were closely related to those of B. kosoyi (identity 98.75%-100%). The ftsZ and rpoB sequences were most closely related to those of B. elizabethae, a recognized human pathogen, with nucleotide similarities of 98.70%-100% and 99.45%-100%, respectively.
Conclusions:
We report the detection of Bartonella DNA in Triatoma kissing bugs in southern China. Although the sample size is limited, the high positive rate of detection of Bartonella DNA, the close relationship of the gene sequences to those of zoonotic Bartonella species, and the distribution of the kissing bugs near human residences, hint at a risk to public health.
... Previous studies revealed that Tr. Rubrofaciata was widely distributed in south China, like Guangxi, Guangdong and Hannan provinces and people bitten were commented on literatures [21][22][23][24]. In the present study, agellates were found in the captured Tr. rubrofaciata, and its morphological, molecular characteristics, prevalence and animal infection experiment were analyzed. ...
... Triatomines were collected in the woodpile and transferred to the laboratory to feed. Triatomine species were identi ed based on morphologically according to the descriptions by Xiao et al. [25], and mitochondrial DNA genes 16S rRNA and cytochrome-b (Cytb) gene were ampli ed and analyzed [21]. ...
... The collected 135 triatomines from the two collecting sites were all identi ed morphologically as Tr. rubrofasciata by the characteristics as previously reported [21]. the T. rubrofasciata 16S rRNA and cytb PCR, yielding 499 bp and 667 bp fragments, are all identical and 100% matched to the Tr. ...
Background
Triatomines (kissing bugs) are natural trypanosome vectors that transmit trypanosome species, including Trypanosoma cruzi, Trypanosoma conorhini and Trypanosoma rangeli. Here we reported the first solid record of Trypansoma conorhini from Triatomia rubrofaciata in China.
Methods
The intestinal contents of the Triatomine rubrofasciata were collected to prepare smears and examined by microscopy. The morphological indices of trypanosome species were measured and calculated. The genomic DNA fragment of trypanosomes was extracted, and the genes of 18S rRNA gene, HSP70 and glycosomal glyceraldehyde-3-phosphate dehydrogenase genes (gGAPDH) were PCR amplified and sequenced. The obtained sequences were subjected to a BLAST search in NCBI and followed by phylogenetic analysis with other homologous trypanosomes. To investigate the prevalence of this trypanosome, 135 T. rubrofasciata samples from different regions of Guangxi were collected and assayed. Moreover, laboratory infection was conducted to test the possible transmission between Tr. rubrofasciata and rats (or mice) though Tr. Rubrofasciata bite.
Results
The parasite found in the intestinal contents of Tr. rubrofaciata, which were collected in the Guangxi region of southern China, exhibits the typical characteristics of epimastigotes, such as the presence of a nucleus, a free flagellum and a kinetoplast. The body length ranged from 6.3–33.9 µm, and flagellum length ranged from 8.7–29.8 µm; the nucleus index was 0.6, and the kinetoplast index was − 4.6. The BLAST analysis showed that the 18S rRNA, HSP70, and gGAPDH sequences of the Trypanosoma sp. exhibit the highest degree of similarity with T. conorhini (99.7%, 99.0%, 99.0%), and formed a well-supported clade close to T. conorhini and T. vespertilionis, while exhibiting a significant distance from T. rangeli and T. cruzi. Our investigation uncovered a high prevalence of Trypanosoma sp. infection in Tr. rubrofaciata up to 36.3% in the field. The laboratory experiments showed that both rats and mice could get Trypansoma sp. infected through bites from wild Tr. rubrofaciata, and lab-feeding Tr. rubrofaciat can get Trypansoma sp. infected through bloodmeals of infected mice.
Conclusion
Trypanosoma conorhini was found in Tr. rubrofasciata in China, as judged by morphology and molecular markers. This parasite had a high prevalence in T. rubrofasciata, and lab experiment showed Trypanosoma conorhini in China could be transmitted between Tr. rubrofasciata and rat(mice) through Tr. rubrofasciata bites; whether this parasite is pathogenic to human need to be future research.
... Most of them live in rural regions of Latin America, but due to emigration of population, Chagas disease has increasingly spread to urban areas and non-endemic countries with non-vectorial transmission routes [13]. In addition, some triatomine vectors, especially the cosmopolitan Triatoma rubrofasciata, also show a considerable potential for further geographical expansion [14][15][16]. Unlike in other blood-sucking insects, T. cruzi is not transmitted by the bite but by infectious faeces which are accidentally rubbed into the bite wound. Further transmission routes include oral consumption of contaminated food or beverages, congenital transmission and the transmission by infected blood products or organ transplantation [17][18][19]. ...
Background
The causative agent of Chagas disease, Trypanosoma cruzi, and its nonpathogenic relative, Trypanosoma rangeli, are transmitted by haematophagous triatomines and undergo a crucial ontogenetic phase in the insect’s intestine. In the process, the parasites interfere with the host immune system as well as the microbiome present in the digestive tract potentially establishing an environment advantageous for development. However, the coherent interactions between host, pathogen and microbiota have not yet been elucidated in detail. We applied a metagenome shotgun sequencing approach to study the alterations in the microbiota of Rhodnius prolixus, a major vector of Chagas disease, after exposure to T. cruzi and T. rangeli focusing also on the functional capacities present in the intestinal microbiome of the insect.
Results
The intestinal microbiota of R. prolixus was dominated by the bacterial orders Enterobacterales, Corynebacteriales, Lactobacillales, Clostridiales and Chlamydiales, whereas the latter conceivably originated from the blood used for pathogen exposure. The anterior and posterior midgut samples of the exposed insects showed a reduced overall number of organisms compared to the control group. However, we also found enriched bacterial groups after exposure to T. cruzi as well as T rangeli. While the relative abundance of Enterobacterales and Corynebacteriales decreased considerably, the Lactobacillales, mainly composed of the genus Enterococcus, developed as the most abundant taxonomic group. This applies in particular to vectors challenged with T. rangeli and at early timepoints after exposure to vectors challenged with T. cruzi. Furthermore, we were able to reconstruct four metagenome-assembled genomes from the intestinal samples and elucidate their unique metabolic functionalities within the triatomine microbiome, including the genome of a recently described insect symbiont, Candidatus Symbiopectobacterium, and the secondary metabolites producing bacteria Kocuria spp.
Conclusions
Our results facilitate a deeper understanding of the processes that take place in the intestinal tract of triatomine vectors during colonisation by trypanosomal parasites and highlight the influential aspects of pathogen-microbiota interactions. In particular, the mostly unexplored metabolic capacities of the insect vector’s microbiome are clearer, underlining its role in the transmission of Chagas disease.
... 2, p. 26-32, 2011 GALVÃO, 2009;CARANHA et al., 2011). Os triatomíneos, em sua maioria, encontram-se por toda região Neotropical, entretanto algumas espécies ocorrem nos Estados Unidos, centro-sul da África, China e sudeste da Ásia e norte da Austrália, onde representam, assim como no Brasil, um grave problema para os seres humanos (MEYMANDI et al., 2018;SHI et al., 2020). ...
... 2, p. 26-32, 2011 GALVÃO, 2009;CARANHA et al., 2011). Os triatomíneos, em sua maioria, encontram-se por toda região Neotropical, entretanto algumas espécies ocorrem nos Estados Unidos, centro-sul da África, China e sudeste da Ásia e norte da Austrália, onde representam, assim como no Brasil, um grave problema para os seres humanos (MEYMANDI et al., 2018;SHI et al., 2020). ...
... 2, p. 26-32, 2011 GALVÃO, 2009;CARANHA et al., 2011). Os triatomíneos, em sua maioria, encontram-se por toda região Neotropical, entretanto algumas espécies ocorrem nos Estados Unidos, centro-sul da África, China e sudeste da Ásia e norte da Austrália, onde representam, assim como no Brasil, um grave problema para os seres humanos (MEYMANDI et al., 2018;SHI et al., 2020). ...
... 2, p. 26-32, 2011 GALVÃO, 2009;CARANHA et al., 2011). Os triatomíneos, em sua maioria, encontram-se por toda região Neotropical, entretanto algumas espécies ocorrem nos Estados Unidos, centro-sul da África, China e sudeste da Ásia e norte da Austrália, onde representam, assim como no Brasil, um grave problema para os seres humanos (MEYMANDI et al., 2018;SHI et al., 2020). ...
... 2, p. 26-32, 2011 GALVÃO, 2009;CARANHA et al., 2011). Os triatomíneos, em sua maioria, encontram-se por toda região Neotropical, entretanto algumas espécies ocorrem nos Estados Unidos, centro-sul da África, China e sudeste da Ásia e norte da Austrália, onde representam, assim como no Brasil, um grave problema para os seres humanos (MEYMANDI et al., 2018;SHI et al., 2020). ...
