Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol.5, No.17, 2015 117 The Current Situation and Diagnostic Approach of Nagana in Africa: A review Eyob Eshetu and Batisa Begejo School of Veterinary Medicine, Wolaita Sodo University, Ethiopia SUMMARY Animal African Trypanosomosis (AAT) or Nagana occurs in 37 sub-Saharan countries covering more than 9 million km 2 , an area which corresponds approximately to one-third of the Africa's total land area. African animal Trypanosomosis continues to be the major constraint of livestock production in sub-Saharan African including Ethiopia. It is caused by protozoan parasites that belong to the genus Trypanosome. The main species of trypanosomes affecting livestock are Trypanosome congolense, T.vivax and those in the T.brucei group. Among others, tests flies play a major role in the transmission of Trypanosomes. They disease cause loss of animal productivity and mortality in severely infected animal if left untreated. The Nangana has a severe impact on agriculture economic losses in cattle production alone are in the range of US$ 1.0 -1.2 billion. A ponderated evaluation extrapolated for the total tsetse-infested lands values total losses, in terms of agricultural Gross Domestic Product, at US$ 4.75 billion per year. The clinical signs of African animal trypanosomosis are not pathognomonic. Therefore; confirmatory diagnosis of this disease is based on clinical diagnosis, parasitological methods, serological test, animal inoculation and molecular tests. However, there are several advantages and disadvantages in relation with the tests. Furthermore, some of the tests are not applicable to the field. Moreover, the presence of antibody in the serum does not necessarily reflect an existing infection, as antibodies’ may persist for several months following recovery. Diagnosis of trypanosomosis should be based on clinical signs and following by laboratory conformation tests. In this manuscript the African animal trypanosomosis and its diagnostic approach is reviewed. Key words: African animal trypanosomosis, Cattle, Diagnosis, Nagana 1. INTRODUCTION African animal trypanosomosis (AAT) is a disease complex caused by tsetse-fly transmitted Trypanosoma congolese, T.vivax and T. brucei brucei, or simultaneous infection with one or more of these trypanosomes. Infection of cattle by one or more of the three African animal trypanosomes results in sub-acute, acute or chronic disease characterized by intermittent fever, anemia, occasional diarrhea and rapid loss of condition and often terminates in death (Mare, 2004). As the illness progresses the animals weaken more and more and eventually become unfit for work, hence the name of the disease "Nagana" which is a Zulu word that means "powerless/useless" (Winkle et al., 2005). Because of Nagana, stock farming is very difficult within the tsetse belt (WHO, 2006). African animal trypanosomosis and its vectors occur in areas of the Sub-Saharan African (SSA) with devastating impact on livestock productivity posing a serious threat to the lives and communities. Of the 165 million cattle found in Africa, only 10 million are found within the tsetse fly free belt, and these are mostly low producing breeds which are maintained on high drug management regimes to keep trypanosomosis at bay (Jones and Davila, 2001). It constitutes the greatest single constraint to livestock and crop production by directly contributing to hunger, poverty, malnutrition and suffering of entire communities in Africa (Pattec, 2002). The disease has also economic importance due to loss of condition, reduction in milk yield, decrease capacity of work (Reghu et al., 2008). Tsetse flies in Ethiopia are confined to southwestern and northwestern regions between longitude 33 o and 38 o E and latitude 5 o and 12 o N covers an area of 220,000km² (NTTICC, 2004). Around 14 million head of cattle, an equivalent number of small ruminants, nearly 7 million equines and 1.8 million camels are at the risk of contracting trypanosomosis at any one time (MoARD, 2004). Six species of trypanosome are recorded in Ethiopia and the most important trypanosomes, in terms of economics loss in domestic livestock, are the tsetse transmitted species: T.congolense, T.vivax and T. brucei group (Abebe, 2005). Accurate diagnosis of trypanosome infections in livestock is required for a proper appreciation of the epidemiology of the disease. However, high parasitaemia are usually evident only in early infections, and in the chronic phase of the disease, parasites any apparently be absent from the blood for long intervals. This is due to the ability of trypanosomes to establish prolonged infections attributed to the phenomenon of antigenic variation.