Search

The bovine trypanosomosis is responsible for economic losses from tropical and subtropical areas of Africa and Latin America. This disease is characterized by fever, anaemia, loss of production and even death. Few studies have been carried out in Ecuador regarding Trypanosoma spp. presence but the species has not been determined in cattle and those have only determined the presence of genus, but not the species. The aim of this study was to identify and characterize the trypanosome species involved in the suspected bovine trypanosomosis outbreak reported in Convento Village in Manabí Province located in the coastal region of Ecuador. Twenty cattle from three farms were sampled. Three samples were positive for T. vivax, using an end-point polymerase chain reaction (PCR) to amplify a fragment of the cathepsin L-like cysteine protease (CatL-like) gene. A phylogenetic tree analysis of these three Ecuadorian isolates showed a close relationship with isolates from South America (Colombia, Brazil and Venezuela) and West Africa (Nigeria). This is the first report of T. vivax in Ecuadorian cattle., (© 2020 Wiley-VCH GmbH.)

Background: Trypanosomes cause disease in humans and livestock in sub-Saharan Africa and rely on tsetse flies as their main insect vector. Nigeria is the most populous country in Africa; however, only limited information about the occurrence and diversity of trypanosomes circulating in the country is available., Methods: Tsetse flies were collected from five different locations in or adjacent to protected areas, i.e. national parks and game reserves, in Nigeria. Proboscis and gut samples were analysed for trypanosome DNA by molecular amplification of the internal transcribed spacer 1 (ITS1) region and part of the trypanosome specific glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene., Results: The most abundant Trypanosoma species found in the tsetse gut was T. grayi, a trypanosome infecting crocodiles. It was ubiquitously distributed throughout the country, accounting for over 90% of all cases involving trypanosomes. Trypanosoma congolense was detected in gut samples from all locations except Cross River National Park, but not in the proboscis, while T. brucei (sensu lato) was not detected at all. In proboscis samples, T. vivax was the most prominent. The sequence diversity of gGAPDH suggests that T. vivax and T. grayi represent genetically diverse species clusters. This implies that they are highly dynamic populations., Conclusions: The prevalence of animal pathogenic trypanosomes throughout Nigeria emphasises the role of protected areas as reservoirs for livestock trypanosomes. The genetic diversity observed within T. vivax and T. grayi populations might be an indication for changing pathogenicity or host range and the origin and consequences of this diversity has to be further investigated.

Trypanosomes of African wild ungulates transmitted by tsetse flies can cause human and livestock diseases. However, trypanosome diversity in wild tsetse flies remains greatly underestimated. We employed FFLB (fluorescent fragment length barcoding) for surveys of trypanosomes in tsetse flies (3086) from the Gorongosa National Park (GNP) and Niassa National Reserve (NNR) in Mozambique (MZ), identified as Glossina morsitans morsitans (GNP/NNR=77.6%/90.5%) and Glossina pallidipes (22.4%/9.5%). Trypanosomes were microscopically detected in 8.3% of tsetse guts. FFLB of gut samples revealed (GNP/NNR): Trypanosoma congolense of Savannah (27%/63%), Kilifi (16.7%/29.7%) and Forest (1.0%/0.3%) genetic groups; T. simiae Tsavo (36.5%/6.1%); T. simiae (22.2%/17.7%); T. godfreyi (18.2%/7.0%); subgenus Trypanozoon (20.2%/25.7%); T. vivax/T. vivax-like (1.5%/5.2%); T. suis/T. suis-like (9.4%/11.9%). Tsetse proboscises exhibited similar species composition, but most prevalent species were (GNP/NNR): T. simiae (21.9%/28%), T. b. brucei (19.2%/31.7%), and T. vivax/T. vivax-like (19.2%/28.6%). Flies harboring mixtures of trypanosomes were common (~ 64%), and combinations of more than four trypanosomes were especially abundant in the pristine NNR. The non-pathogenic T. theileri was found in 2.5% while FFLB profiles of unknown species were detected in 19% of flies examined. This is the first report on molecular diversity of tsetse flies and their trypanosomes in MZ; all trypanosomes pathogenic for ungulates were detected, but no human pathogens were detected. Overall, two species of tsetse flies harbor 12 species/genotypes of trypanosomes. This notable species richness was likely uncovered because flies were captured in wildlife reserves and surveyed using the method of FFLB able to identify, with high sensitivity and accuracy, known and novel trypanosomes. Our findings importantly improve the knowledge on trypanosome diversity in tsetse flies, revealed the greatest species richness so far reported in tsetse fly of any African country, and indicate the existence of a hidden trypanosome diversity to be discovered in African wildlife protected areas., (Copyright © 2017 Elsevier B.V. All rights reserved.)

African animal trypanosomosis (AAT) is a parasitic disease considered to be one of the greatest constraints to cattle production in Tanzania. There is insufficient information on seasonal occurrence of AAT and management practices in Monduli District of the Maasai Steppe ecosystem to guide and prioritize AAT control programs. A cross-sectional survey was undertaken in 10 randomly selected villages of Monduli District. Information on seasonal animal movements, including wildlife interaction, and AAT management practices was gathered using a standardized questionnaire with 130 pastoralists. Blood samples were collected from a total of 960 cattle, in wet and dry seasons. An entomological survey was also undertaken in the dry season. Polymerase chain reaction targeting the internal transcribed spacer 1 (ITS1) was used for parasite identification in cattle blood and in tsetse flies. The overall apparent prevalence of AAT in cattle was 5.8% (95% CI of 4.1-8.3) and 4.2% (95% CI of 2.7-6.3) during wet and dry reasons, respectively. Trypanosoma vivax was the most common species identified in cattle. All tsetse flies (n = 426) collected were trapped in Esilalei village which is in close proximity to Lake Manyara National Park. Tsetse fly infection status was determined to be 7.0%; (CI 95% of 4.9-9.8%) with nearly 50% of infections due to T. congolense. All 130 cattle owners reported that they could easily recognize AAT and the majority (75%) identified the most prominent clinical signs. Nearly all owners (98.5%) identified that tsetse flies were responsible for AAT transmission. All cattle owners (100%) reported the use of trypanocides for AAT treatment, while 2.3% reported to also use herbal medicine. The trypanocides, Novidium® and Berenil®, were the most frequently reported commercial drugs and were used by 42% of cattle owners. Vector control by hand spraying was reported by the majority (90.8%) of cattle owners, while dipping and deployment of insecticide-impregnated targets were reported by few cattle owners (16.2% and 5.4%, respectively). The majority of cattle owners (83.1%) reported to move cattle away from home villages during the dry season with many migrating to areas in close proximity to wildlife parks. This study confirms the presence of circulating pathogenic trypanosomes in tsetse flies which continue to pose a threat to Maasai cattle. The seasonal movement of cattle during the dry season was associated with more clinical cases of cattle trypanosomosis. This study demonstrates the need to strengthen surveillance and control strategies for AAT., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Animal African Trypanosomiasis (AAT) is caused by several species of trypanosomes including Trypanosoma congolense, T. vivax, T. godfreyi, T. simiae and T. brucei. Two of the subspecies of T. brucei also cause Human African Trypanosomiasis. Although some of them can be mechanically transmitted by biting flies; these trypanosomes are all transmitted by tsetse flies which are the cyclical vectors of Trypanosoma congolense, T. godfreyi, T. simiae and T. brucei. We present here the first report assessing the prevalence of trypanosomes in tsetse flies in Nigeria using molecular tools., Methods: 488 tsetse flies of three species, Glossina palpalis palpalis, G. tachinoides and G. morsitans submorsitans were collected from Wuya, Niger State and Yankari National Park, Bauchi State in 2012. Trypanosomes were detected and identified using an ITS1 PCR assay on DNA purified from the 'head plus proboscis' (H + P) and abdomen (ABD) parts of each fly., Results: T. vivax and T. congolense Savannah were the major parasites detected. Trypanosomes prevalence was 7.1 % in G. p. palpalis, 11.9 % in G. tachinoides and 13.5 % in G. m. submorsitans. Prevalences of T. congolense Savannah ranged from 2.5 to 6.7 % and of T. vivax were approximately 4.5 %. Trypanosoma congolense Forest, T. godfreyi and T. simiae were also detected in the site of Yankari. The main biological and ecological determinants of trypanosome prevalence were the fly sex, with more trypanosomes found in females than males, and the site, with T. congolense subspp. being more abundant in Yankari than in Wuya. As expected, the trypanosome species diversity was higher in Yankari National Park than in the more agricultural site of Wuya where vertebrate host species diversity is lower., Conclusions: Our results show that T. congolense Savannah and T. vivax are the main species of parasite potentially causing AAT in the two study sites and that Yankari National Park is a potential reservoir of trypanosomes both in terms of parasite abundance and species diversity.

The use of a single restriction fragment length polymorphism (RFLP)-PCR assay which is able to characterise all important bovine trypanosome species was evaluated for the detection of mixed infections with Trypanosoma brucei brucei, Trypanosoma theileri, Trypanosoma congolense and Trypanosoma vivax. Results showed that mixed infections are detectable at a minimum ratio of 2%/98% of standardised DNA solutions with a concentration of 10 ng ml(-1). All mixed infections gave clear profiles that could be easily differentiated except with T. theileri and T. congolense where the T. theileri band was concealed by the T. congolense profile.

The polymerase chain reaction was used to characterize the trypanosomes infecting Glossina morsitans submorsitans and G. tachinoides in the game ranch of Nazinga, Burkina Faso, situated near an agropastoral zone. Dissection of 435 tsetse flies, and PCR analysis of 166 infected flies were conducted to assess the epidemiological situation. Trypanosomes of the Nannomonas subgenus were the most abundant in the two tsetse species (80.4% and 73.7% of identified infections in G. m. submorsitans and G. tachinoides respectively). T. vivax and T. brucei infection rates were comparable between the two tsetse species. Mature infection pattern identified by PCR differed from overall infections, mainly because T. simiae infections did not mature, whereas T. vivax represented the predominant taxon. Parasitological and PCR results showed some discrepancies; possibly some typical Duttonella strains could not be recognized by the sets of primers used. The technologies used in this work helped to determine the high trypanosomosis risk in this area.

Following the discovery of four cases of African human trypanosomiasis, an entomological survey was conducted along the Mouhoun river in southwest Burkina Faso to collect Glossina palpalis gambiensis and G.tachinoides. Among 226 flies dissected, 4.87% (eleven individuals) were infected in midgut or proboscis, but never in the salivary glands. Polymerase chain reaction analysis was undertaken, and was able to characterize all the proboscis infections, and half of the midgut infections. Only Trypanosoma simiae and T. vivax were found in the organs of infected flies, in single or mixed-species infections. Ten more flies, negative with parasitological examination, were tested with Trypanozoon primers and remained negative. The epidemiological significance of the absence of T.brucei group infections in wild tsetse populations and the presence of T.simiae in G.p.gambiensis are discussed.

A sensitive and specific nitrocellulose (NC) membrane-based dot-ELISA, utilizing a panel of monoclonal antibodies (mAbs), was developed for differentiation between in vitro-derived procyclic forms of Trypanosoma brucei, T. congolense and T. simiae, and epimastigotes of T. vivax. Trypanosomes in suspension were applied onto NC membrane in dots and probed with unlabelled trypanosome species-specific mAbs. Bound mAb was revealed by enzyme labelled anti-mouse IgG and precipitable chromogenic substrate. The assay detected the aforementioned trypanosome species in both single and artificially mixed preparations. Ten T. brucei, 4 T. vivax, 7 T. congolense and 3 T. simiae procyclic stocks and clones from different geographical areas were tested and identified using the specific mAbs in the dot-ELISA which had a specificity of 100%. Some of the T. brucei, T. congolense and Nannomonas-specific mAbs could detect as few as 10 trypanosomes/dot, whilst 1 T. vivax mAb was able to detect a minimum of 100 trypanosomes/dot in monospecies preparations. A concentration of 1 x 10(4) trypanosomes/microliters/dot was eventually determined as ideal for testing in the dot-ELISA. Antigen dots stored at 4 degrees C under desiccated conditions did not show any loss in activity for up to 90 days. However, when stored under similar conditions at room temperature (17-26 degrees C), the T. congolense-specific antigen remained unaffected up to 60 days, and then showed decreased activity when tested on day 90.