Abstract

Trypanosomosis is the most important and serious pathogenic protozoal disease of camel caused by Trypanosoma species. Trypanosome evansi parasite has a wide range of distribution throughout tropical and subtropical regions of the world. Mostly, camels suffer from trypanosomosis caused by T. evansi that is transmitted mechanically, non-cyclically, by haematophagus flies such as horseflies (Tabanus) and stable flies (Stomoxys) which are endemic in Africa, Asia and South America, although in America the vampire bat also acts as a vector as well as reservoir hosts. The disease manifests itself in different forms: acute, sub-acute, chronic and in-apparent. Anaemia appears to be a major component of the pathology of surra and generally the degree of anaemia might be considered as an indicator of the disease severity. Control of camel trypanosomosis depends mainly on the use of curative and prophylactic drugs even though this strategy is faced with various problems. Surra has a wide host spectrum, the main host species varies with the geographical region. In Africa, beyond the northernmost limits of the tsetse fly belt, and in parts of East Africa, camels are the most important host, whilst in Central and South America the horse is principally affected. In Asia, a much wider range of hosts is involved, including cattle, buffalo and pigs. The disease is most severe in horse, donkey, mules, camels, dogs and cats. T. evansi, like other pathogenic trypanosomes induce a generalized immune-suppression of both humoral antibody response and T cell- mediated immune responses. As a result, in the long term, the host's immune responses fail and it succumbs to either the overwhelming parasite load or to secondary infection, consequently leading to occurrence of the trypanosome-induced immunopathology. This paper reviews the epidemiology of the disease and host response against the parasite.

Key words: Trypanosomosis, Trypanosome evansi, flies, hosts.