Original Research

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

Purity K. Gitonga, Kariuki Ndung’u, Grace A. Murilla, Paul C. Thande, Florence N. Wamwiri, Joanna E. Auma, Geoffrey N. Ngae, James K. Kibugu, Richard Kurgat, John K. Thuita
Onderstepoort Journal of Veterinary Research | Vol 84, No 1 | a1412 | DOI: https://doi.org/10.4102/ojvr.v84i1.1412 | © 2017 Purity K. Gitonga, Kariuki Ndung’u, Grace A. Murilla, Paul C. Thande, Florence N. Wamwiri, Joanna E. Auma, Geoffrey N. Ngae, James K. Kibugu, Richard Kurgat, John K. Thuita | This work is licensed under CC Attribution 4.0
Submitted: 15 December 2016 | Published: 27 June 2017

About the author(s)

Purity K. Gitonga, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Kariuki Ndung’u, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Grace A. Murilla, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Paul C. Thande, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Florence N. Wamwiri, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Joanna E. Auma, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Geoffrey N. Ngae, Kenya Food Crop Research Institute, Nairobi, Kenya
James K. Kibugu, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
Richard Kurgat, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya
John K. Thuita, Kenya Agricultural and Livestock Research Organization – Biotechnology Research Institute (KALROBioRI), Kikuyu, Kenya

Abstract

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.

Keywords

Trypanosoma brucei; Trypanosoma congolense; mice; virulence and tsetse infectivity

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Crossref Citations

1. Differential virulence of Trypanosoma brucei rhodesiense isolates does not influence the outcome of treatment with anti-trypanosomal drugs in the mouse model
Kariuki Ndung’u, Grace Adira Murilla, John Kibuthu Thuita, Geoffrey Njuguna Ngae, Joanna Eseri Auma, Purity Kaari Gitonga, Daniel Kahiga Thungu, Richard Kiptum Kurgat, Judith Kusimba Chemuliti, Raymond Ellie Mdachi, Martin Chtolongo Simuunza
PLOS ONE  vol: 15  issue: 11  first page: e0229060  year: 2020  
doi: 10.1371/journal.pone.0229060