A socio-economic study of Fasciola infections in cattle and sheep at the Etoudi slaughterhouse, Yaoundé, Cameroon.

A cross-sectional socio-economic study of fascioliasis in livestock was carried out at the Livestock Development Cooperation (SODEPA) slaughterhouse in Etoudi, Yaoundé during the periods covering the beginning and late dry season in the northern and eastern regions of Cameroon. A total of 768 cattle and 267 sheep were inspected for the presence of Fasciola species. The overall infection rate in cattle and sheep was 18% (n = 767) and 27% (n = 267), respectively. For the animals that were Fasciola positive, a total of 267.86 kg of liver in cattle was condemned, resulting in a loss of US$1124, while a total of 57 kg of liver was condemned from the sheep population, amounting to a loss of US$114. A total of US$76,097 was determined as losses incurred from condemnation of liver for both cattle and sheep per annum based on the total number slaughtered each year. The findings indicate that fascioliasis is present in cattle and sheep slaughtered in Cameroon and that it causes great economic losses due to condemnation of liver. The local climatic conditions, husbandry systems and the presence of snails (intermediate hosts) are probably the main factors influencing the incidence of the disease and may account for the epidemiological significance found in this study.

Molecular identification of bloodmeal sources and trypanosomes in Glossina spp., Tabanus spp. and Stomoxys spp. trapped on cattle farm settlements in southwest Nigeria.

The interactions of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest Nigeria are not yet well understood. Trypanosoma (Trypanosomatida: Trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera Glossina (Diptera: Glossinidae), Tabanus (Diptera: Tabanidae) and Stomoxys (Diptera: Muscidae) collected using Nzi traps in cattle settlements in southwest Nigeria. Sequenced cytochrome B mitochondrial DNA segments obtained from vector digestive tracts identified bloodmeal sources from eight host species, namely human, cattle, hippopotamus, giraffe, gazelle, spotted hyena, long-tailed rat and one unidentified species. Overall, 71.1% [95% confidence interval (CI) 63.0-78.1], 33.3% (95% CI 21.9-47.0) and 22.2% (95% CI 16.2-29.9), respectively, of Glossina, Tabanus and Stomoxys flies were positive for trypanosomes. The observed trypanosome species were Trypanosoma vivax, Trypanosoma congolense, Trypanosoma brucei, Trypanosoma evansi, Trypanosoma simiae and Trypanosoma godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% Tr. vivax, 51.1% Tr. b. brucei, 5.2% Tr. congolense, 4.4% Tr. simiae and 24.4% mixed infections) than in other flies and the main determinants in all flies were seasonal factors and host availability. To the best of the present group's knowledge, this is the first report of Trypanosoma species in Tabanus and Stomoxys flies in Nigeria. It indicates that vector control programmes should always consider biting flies along with tsetse flies in the control of human and animal trypanosomiasis.

Antioxidants promote establishment of trypanosome infections in tsetse.

Efficient, 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.