The Current Situation and Diagnostic Approach of Nagana in Africa: A review

Abstract

Animal African Trypanosomosis (AAT) or Nagana occurs in 37 sub-Saharan countries covering more than 9 million km², 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