A high level of mixed Trypanosoma brucei infections in tsetse flies detected by three hypervariable minisatellites

SUMMARYEfficient, cyclical transmission of trypanosomes through tsetse flies is central to maintenance of human sleeping sickness and nagana across sub-Saharan Africa. Infection rates in tsetse are normally very low as most parasites ingested with the fly bloodmeal die in the fly gut, displaying the characteristics of apoptotic cells. Here we show that a range of antioxidants (glutathione, cysteine, N-acetyl-cysteine, ascorbic acid and uric acid), when added to the insect bloodmeal, can dramatically inhibit cell death of Trypanosoma brucei brucei in tsetse. Both L- and D-cysteine invoked similar effects suggesting that inhibition of trypanosome death is not dependent on protein synthesis. The present work suggests that antioxidants reduce the midgut environment protecting trypanosomes from cell death induced by reactive oxygen species.

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Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v84i1.1412 ◽

2017 ◽

Vol 84 (1) ◽

Cited By ~ 2

Author(s):

Purity K. Gitonga ◽

Kariuki Ndung’u ◽

Grace A. Murilla ◽

Paul C. Thande ◽

Florence N. Wamwiri ◽

...

Keyword(s):

Survival Time ◽

Trypanosoma Brucei ◽

Acute Infection ◽

Glossina Pallidipes ◽

Trypanosoma Congolense ◽

Tsetse Fly ◽

Economic Losses ◽

Entire Group ◽

Tsetse Flies ◽

African Countries

African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.). In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6). We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP) periods were 8.4 ± 0.9 (range, 4–11) and 4.5 ± 0.2 (range, 4–6) for T. congolense and T. brucei isolates, respectively (p < 0.01). Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05) shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

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Human African trypanosomiasis

Oxford Textbook of Medicine ◽

10.1093/med/9780199204854.003.070810_update_001 ◽

2010 ◽

pp. 1119-1127

Author(s):

August Stich

Keyword(s):

West Africa ◽

East Africa ◽

Trypanosoma Brucei ◽

Human African Trypanosomiasis ◽

Protozoan Parasite ◽

Sleeping Sickness ◽

Tsetse Flies ◽

African Trypanosomiasis ◽

Tropical Africa

Human African trypanosomiasis (HAT, sleeping sickness) is caused by two subspecies of the protozoan parasite Trypanosoma brucei: T. b. rhodesiense is prevalent in East Africa among many wild and domestic mammals; T. b. gambiense causes an anthroponosis in Central and West Africa. The disease is restricted to tropical Africa where it is transmitted by the bite of infected tsetse flies (...

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Human African trypanosomiasis

Oxford Textbook of Medicine ◽

10.1093/med/9780198746690.003.0169 ◽

2020 ◽

pp. 1451-1459

Author(s):

Reto Brun ◽

Johannes Blum

Keyword(s):

Trypanosoma Brucei ◽

Human African Trypanosomiasis ◽

Specific Treatment ◽

Protozoan Parasite ◽

Control Measures ◽

Tsetse Flies ◽

African Trypanosomiasis ◽

Control Programmes ◽

The 1960S ◽

Stage 1

Human African trypanosomiasis (sleeping sickness) is caused by subspecies of the protozoan parasite Trypanosoma brucei. The disease is restricted to tropical Africa where it is transmitted by the bite of infected tsetse flies (Glossina spp.). Control programmes in the 1960s were very effective, but subsequent relaxation of control measures led to recurrence of epidemic proportions in the 1980s and 1990s. Control is now being regained. Untreated human African trypanosomiasis is almost invariably fatal. Specific treatment depends on the trypanosome subspecies and the stage of the disease. Drugs used for stage 1 include pentamidine and suramin, and for stage 2 include melarsoprol, eflornithine, and nifurtimox, but regimens are not standardized, and treatment is difficult and dangerous; all of the drugs used have many side effects, some potentially lethal.

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A global sensitivity analysis for African sleeping sickness

Parasitology ◽

10.1017/s0031182010001496 ◽

2010 ◽

Vol 138 (4) ◽

pp. 516-526 ◽

Cited By ~ 26

Author(s):

STEPHEN DAVIS ◽

SERAP AKSOY ◽

ALISON GALVANI

Keyword(s):

Trypanosoma Brucei ◽

Control Strategies ◽

Sleeping Sickness ◽

Sensitivity Analyses ◽

Tsetse Flies ◽

East African ◽

African Sleeping Sickness ◽

Regular Treatment ◽

Global Sensitivity ◽

Parameter Ranges

SUMMARYAfrican sleeping sickness is a parasitic disease transmitted through the bites of tsetse flies of the genus Glossina. We constructed mechanistic models for the basic reproduction number, R0, of Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, respectively the causative agents of West and East African human sleeping sickness. We present global sensitivity analyses of these models that rank the importance of the biological parameters that may explain variation in R0, using parameter ranges based on literature, field data and expertize out of Uganda. For West African sleeping sickness, our results indicate that the proportion of bloodmeals taken from humans by Glossina fuscipes fuscipes is the most important factor, suggesting that differences in the exposure of humans to tsetse are fundamental to the distribution of T. b. gambiense. The second ranked parameter for T. b. gambiense and the highest ranked for T. b. rhodesiense was the proportion of Glossina refractory to infection. This finding underlines the possible implications of recent work showing that nutritionally stressed tsetse are more susceptible to trypanosome infection, and provides broad support for control strategies in development that are aimed at increasing refractoriness in tsetse flies. We note though that for T. b. rhodesiense the population parameters for tsetse – species composition, survival and abundance – were ranked almost as highly as the proportion refractory, and that the model assumed regular treatment of livestock with trypanocides as an established practice in the areas of Uganda experiencing East African sleeping sickness.

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Prevalence of Cattle Trypanosomosis and Apparent Density of Its Fly Vectors in Bambasi District of Benishangul-Gumuz Regional State, Western Ethiopia

Veterinary Medicine International ◽

10.1155/2020/8894188 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Morka Amante ◽

Hika Tesgera

Keyword(s):

Trypanosoma Brucei ◽

Body Condition ◽

Apparent Density ◽

Tsetse Fly ◽

Meat Production ◽

Tsetse Flies ◽

Trypanosoma Vivax ◽

Trypanosome Species ◽

Cross Sectional ◽

Significant Difference

Trypanosomosis is the most serious disease of cattle, which causes great socioeconomic losses in the country. Its socioeconomic impact is reflected on direct losses due to mortality, morbidity, and reduction in milk and meat production, abortion and stillbirth, and also costs associated with combat of the disease are direct losses. A cross-sectional study was carried out to assess the prevalence of cattle trypanosomosis, and the apparent density and distribution of its fly vectors in selected study areas. The methods employed during the study were buffy coat technique for parasitological study and deploying trap for the collection of tsetse flies. A total of 1512 flies were trapped, and among them, 1162 were tsetse flies while 350 were biting flies. Higher apparent density for tsetse fly (7.7 F/T/D) followed by Stomoxys (0.9 F/T/D), Tabanus (0.8 F/T/D), and Hematopota (0.6 F/T/D) was recorded. Out of 638 examined cattle, the overall prevalence of trypanosomosis in the study area was 9.1% (58/638). Out of positive cases, Trypanosoma congolense (7.7%) was the dominant trypanosome species followed by Trypanosoma vivax (0.9%), Trypanosoma brucei (0.2%), and mixed infection of Trypanosoma brucei and Trypanosoma vivax (0.3%). There was no a significant difference (p>0.05) in trypanosome infection between age, sex, and trypanosome species. The prevalence of trypanosomosis on the bases of body condition was 2.8% for poor, 5.5% for medium, and 0.8% for good body condition. The overall prevalence of anemia was (36.8%), and presence of anemia was higher in trypanosome positive animals (62.5%) than in negative animals (34.3%) which is statistically significant (p<0.05, CI = 1.794–5.471). The overall mean packed cell volume (PCV) value for examined animals was 25.84 ± 0.252SE. Mean (PCV) of parasitaemic cattle (9.1%) was significantly (p<0.05) lower than that of aparasitaemic cattle (90%). This survey showed that trypanosomosis is still a core problem for livestock production of the study area. Therefore, more attention should be given to the control of both the disease and its vectors.

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The development of Trypanosomes in tsetse flies

Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character ◽

10.1098/rspb.1910.0028 ◽

1910 ◽

Vol 82 (556) ◽

pp. 368-388 ◽

Cited By ~ 8

Keyword(s):

East Africa ◽

Trypanosoma Brucei ◽

Royal Society ◽

Infected Animal ◽

Lake Victoria ◽

Tsetse Flies ◽

Trypanosoma Vivax ◽

Single Experiment ◽

Trypanosoma Gambiense ◽

Glossina Palpalis

In the 'Proceedings,' of the Royal Society (B, vol. 81, 1909) a paper was published describing a single experiment illustrating the development of Trypanosoma gambiense in Glossina palpalis This experiment was carried out at Mpumu, Uganda, near Lake Victoria, in the spring of 1909. Since that date many experiments, on the same lines, have been made, not only with Trypanosoma gambiense but also with Trypanosoma dimorphon, Trypanosoma nanum , and Trypanosoma vivax . It is proposed to describe these further experiments in this paper. It will be remembered that Kleine, in German East Africa, at the end of 1908, made the discovery that Glossina palpalis could convey Trypanosoma brucei for some 50 days after the fly had fed on an infected animal. Following Kleine’s lead, our experiments were carried out, at first with Lake-shore flies, afterwards with flies bred in the laboratory.

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