Expanding Our Horizons: Trypanosomes in bovine

            We have already spoken of how different vectors can be more or less suitable for the transfer of Trypanosoma catostomi (Jones and Woo, 1992). It can be assumed that the same means of vector specificity can be translated not only to other species of Trypanosoma, but also to any parasite or disease inducing organism which has the possibility to be vectored. This week, I will summarize the results of Efrem et al., (2010) and how the activity of vectors and other trypanosomes can be altered by location, seasons, and even how the rate of infection can differ due to age of the definitive host.

            Tsetse transmitted African Animal Trypanosomosis (AAT) is estimated to put between 40 and 60 cattle in Africa at risk (Holmes et al., 2004) and is transmitted by the tsetse fly of the genus Glossina. This particular disease is caused by Trypanosoma cogolense, Trypanosoma vivax, and Trypanosoma brucei. Efram et al., (2010) specifically studied how prevalent the disease was, as well as the densities and distribution of Glossina during dry and rainy seasons in the Gimbi district west of Addis Ababa in Ethiopia. The method of study was conducted mainly by a questionnaire survey issued to farmers. Farmers were asked to provide information on how often Glossina and bovine trypanosomosis occurred, as well as how often drugs to treat the disease were used and their other methods of controlling the disease and tsetse fly. The prevalence of flies was determined by placing monoconial pyramidal traps in areas of different elevation during wet and dry seasons. Density of trypanosomes within the bovines was also determined by collecting blood samples from the cattle at each elevation during the two seasons. Prevalence of infection based on age of bovines was also determined using these same blood samples.

            Researchers determined that T. congolense was the cause of 66.2% of infections. Adult cattle seemed to be infected significantly more often than younger cattle. AAT seemed to be much more prevalent during the rainy season than the dry season and the similar conclusions were reached with regards to the prevalence of Glossina. Finally, it was also concluded that trypanosomosis was also more common in lowland areas.

            The information provided by Efram et al., (2010) shows that species of Trypanosoma possess even more specific qualities. Not only is there vector specificity, but it seems that infection can be limited to altitude, age, and even the time of year (which suggests that species of Trypanosoma are sensitive to climate). This information is supported in the medical field specifically with the use of Influenza vaccines (vaccines are strongly suggested during colder seasons).

Literature Cited

Efram, D.B., H.T., Yacob, A.T, Hagos, and A.K. Basu. 2010. Bovine trypanosomosis in Gimbi district of Western Oromia, Ethiopia. Animal Biology. 60: 123-131.

Holmes, P.H., Eisler, M.C. and Geerts, S. 2004. Current chemotherapy of animal trypanosomiasis. In: Maudin, I., Holmes, P.H. and Miles, M.A. (eds.) The Trypanosomiases. CABI, UK. pp. 431-444.

Jones, S.R.M., and Woo, P.T.K. 1992. Vector specificity of Trypanosoma catostomi and its infectivity to freshwater fishes. Journal of Parasitology. 70(1): pp. 87-92.