International Research Journal of Agricultural Science Vol. 1(3) pp. 096-097 May 2011 Available online http://www.interesjournals.org/IRJAS Copyright ©2011 International Research Journals Short Communication A two year study on bovine trypanosomosis in Kassala State, Eastern Sudan (2007-2008) Gumaa MM * , Sarah Abusalab, Omer MM, Salih DA, Mulla SA, Omer EA, Ahmed AM. Kassala Veterinary Research Laboratory (KVRL), Animal Resources Research Corporation P.O. Box 237 Kassala, Sudan Accepted 11 April, 2011 In this study, the infection rate of bovine trypanosomosis in Kassala state was 1.58% of total animals examined (1008) in the period from 2007 to 2008. The effect of seasonality in the prevalence of the disease was found to be 0.8% in rainy season and 2.7% in winter, there was no infected cases reported in summer. It is concluded that the prevalence rate of the disease was higher in winter season than rainy season. Keywords: Bovine trypanosomosis, prevalence rate, Kassala State, Sudan INTRODUCTION Trypanosomosis in animals is caused by extracellular flagellate protozoan parasites under the genus Trypanosoma of Family Trypanosomatidae. In cattle there are different species of trypanosome causes the disease these are Trypanosoma congolense, Trypanosoma brucei brucei and Trypanosoma vivax (Uilenberg and Boyt, 1998) which transmit cyclically by Glossina spp. ( Tse tse flies) in humid and semi- humid zones in sub- Sahara Africa in an area of 10 million Km 2 (Black and Seed, 2002). T. vivax and T.congolense can be transmitted mechanically by biting flies such as Tabanids and Stomoxys (Desquesenes and Dia, 2003a, Desquesenes and Dia, 2003b). Abdalla et al. (2005) reported that out-side the tse tse belt T. vivax is the causative agent of the disease in cattle in central Sudan during dry and wet seasons. In Kassala state, the incidence of the disease was 0.6% between years 1994 and 2003 (Salih et al., 2005). This work reports the prevalence rate of bovine trypanosomosis in Kassala State during 2007-2008 and the role of the seasonality in the incidence of the disease. MATERIALS AND METHODS Kassala State lies between latitudes 15 o -17 o N and 15 o - 24 o S and longitudes 37 o -55 o E and 35 o -55 o W. A total of *Corresponding author: mmustafa80@hotmail.co.uk 1008 blood samples were collected from cattle herds in Kassala, Elgash, Atbara river and Setit localities. The study was carried out between January 2007 and December 2008. The sampling was done in winter (November, December, January and February); summer (March, April, May and June) and autumn (July, August, September and October). Samples examined were thin dry blood smears stained with Giemsa 10% for 20 minutes, and then examined using light microscope. RESULTS AND DISCUSSION In this study, 16 out of 1008 (1.58%) were positive to Trypanosoma vivax. This incidence rate was much higher than the previous years 2004 to 2006 which was 0.1% (Omer et al., 2007); this might be due to the high levels of rainfall in year 2007 (average 105.5 ml) during autumn. The concentration of vectors directly proportional with high levels of rainfall (Karib, 1961). The prevalence rate of bovine trypanosomosis, in the Sudan outside the testse area, is influenced by annual rainfall (Rahman, 2005). The study conducted in Sinjah area (Central Sudan) between years 1991 and 1994 showed that infection rate was 1% in 1992, 6% in 1993, and 27% in 1994 when the rates of rainfall were 475.3mm, 423.0mm and 938.3mm, respectively (Rahman, 2005). As shown in table (1) the infection rate in winter is higher than autumn, while no positive animals detected in summer. Similar findings reported by Abdelsalam, (1996)