Vector identification, prevalence and anemia of bovine trypanosomosis in Yayo District, Illubabor Zone of Oromia Regional State, Ethiopia

Trypanosomosis is one of the major impediments to livestock development andagricultural production in Ethiopia. It is cyclically transmitted by tsetse flies butalso mechanically tsetse flies and by other biting flies. A cross-sectional study wasconducted to identify the density and diversity of vectors and also the prevalence ofbovine trypanosomosis from October, 2014 to May, 2015. The study was conductedin four selected settlement areas of the Yayo district in the Illubabor zone of OromiaRegional State, Ethiopia. Standard methods of sampling and identification were employed for both entomological and parasitological examination. Four species of the genus Glossina (Glossina morsitans submorsitans, Glossina pallidipes, Glossina tachinoides and Glossina fuscipes) and two genera of biting flies (Stomoxys and Tabanus) were caught and identified. The overall apparent density of flies caught was 1095 (9.78 flies per trap per day), of which 410 (3.7 flies per trap per day) was Glossina species. Out of a total 488 cattle examined, 19 (3.9%; 95% CI: 2.36%-6.1%) were found infected with trypanosomes. Three species were detectedin the study area namely T. congolense 16(84.21%), T. vivax 2(10.53%) and T. brucei 1(5.26%). The prevalence of trypanosomosis was not significantly affected by all risk factors considered (p>0.05). Trypanosomosis significantly affected the status of anemia or packed cell volume (p<0.05). The mean PCV of parasitemic animals were significantly lower than that of aparasitemic ones (P<0.05). The prevalence of anemia was 19.67% (95%CI: 16.24-23.48) and not significantly affected by the different risk factors considered (P>0.05) with the exception of Geri (Peasant association) which have shown the lowest anemia prevalence  (P<0.05).The relative abundance of Glossina species caught and trypanosome detected confirmed the continuous challenge of the disease in the settlement areas. Therefore, the ongoing community based tsetse and trypanosomosis  prevention/control strategy should be strengthened in the area.Keywords: Traps, Glossina, Packed cell volume, Trypanosoma, Buffy coat, Yayo distric

Anaemia Associated with Trypanosomes Infections in Cattle of West Gojjam Zone, Northwest Ethiopia

Background. African animal trypanosomosis is a major veterinary problem over a large area of the tsetse belt region of Africa. Anaemia is a cardinal sign of trypanosome infections. The mechanism of anaemia due to trypanosomosis is complex and multifactorial in origin. Packed cell volume (PCV) usually gives an indication of the anaemia and disease status of a trypanosome-infected animal. Methods. A cross-sectional study was conducted from December 2017 to January 2018 in West Gojjam zone, Northwest Ethiopia, to determine the trypanosome infections rate and the possible correlation between parasitic infection and anaemia using the dark ground buffy coat technique, Giemsa-stained thin blood smear, and PCV reading on a haematocrit reader. Results. The overall trypanosomosis prevalence was 7.81%, 95% CI = 7.45–8.17. Trypanosoma congolense (4.25%) and T. vivax (3.56%) were the trypanosomes species identified in the studied area. PCV for all sampled cattle was analysed to estimate the degree of anaemia. From the total examined animals (N = 730), 356 (48.77%) were anaemic and 374 (51.23%) were nonanaemic. The mean PCV of parasitemic cattle was significantly lower (21.09%, 95% CI = 20.13–22.05) than that of aparasitemic ones (25.96%, 95% CI = 25.68–26.24). There was a positive association between trypanosome infection and anaemia. Although both trypanosome species are significantly associated with a decreased herd mean PCV (<24), the mean PCV of cattle infected with T. congolense (19.45%) was lower than that of infected with T. vivax (23.04%). The herd mean PCV was not significantly associated to locations, age, and sex of the studied animals. Conclusions. The study confirms that the prevalence of trypanosomes infections and herd mean PCV has a significant association. The mean herd PCV can be a useful cheap tool to screen for possible trypanosome infection. However, there were cattle positive for trypanosomes having mean PCV within the reference interval and negative animals with anaemia. Furthermore, PCV reading should be confirmed by other diagnostic techniques to accurately conclude that trypanosomosis is the only cause of anaemia

Bovine trypanosomosis and its fly vectors in three selected settlement areas of Hawa-Gelan district, western Ethiopia

A cross-sectional study aimed at investigating the species diversity of fly vectors and estimating the prevalence of bovine trypanosomosis was carried out from October 2009 to May 2010 in selected settlement areas of the Hawa-Gelan district in the western Wollega zone of Ethiopia. Standard methods of sampling and identification were employed for both entomological and parasitological examination. Three species of the genus Glossina (Glossina pallidipes, Glossina morsitans submorsitans and Glossina fuscipes) and two genera of biting flies (Stomoxys and Tabanus) were caught and identified. The overall apparent density of Glossina species caught was 10.5 flies per trap per day, with a higher proportion of female flies (57.2%). Out of a total 389 cattle examined, 42 (10.8%; 95% CI: 7.89% – 14.3%) were found infected with trypanosomes. Three trypanosome species were detected in the study area, namely Trypanosoma congolense (54.8%), Trypanosoma brucei (23.8%) and Trypanosoma vivax (21.4%). The prevalence of trypanosomosis was found to be significantly (p < 0.05) higher in cattle with poor body condition. There was an association between mean packed cell volume (PCV) and the occurrence of parasitaemia (χ2 = 49.5, p < 0.05). About 95.2% of cattle that were positive for trypanosomes had a PCV less than the lower limit for cattle. Considering the current result, bovine trypanosomosis seems to be a serious constraint for agricultural activities in the settlement areas of the Hawa-Gelan district and seems to be associated with the presence of Glossina species. Therefore, application of control methods through community involvement to reduce the Glossina species infestation level is likely to increase animal productivity