Trypanosoma evansiand Surra: A Review and Perspectives on Origin, History, Distribution, Taxonomy, Morphology, Hosts, and Pathogenic Effects

Abstract

Trypanosoma evansi, the agent of “surra,” is a salivarian trypanosome, originating from Africa. It is thought to derive from Trypanosoma brucei by deletion of the maxicircle kinetoplastic DNA (genetic material required for cyclical development in tsetse flies). It is mostly mechanically transmitted by tabanids and stomoxes, initially to camels, in sub-Saharan area. The disease spread from North Africa towards the Middle East, Turkey, India, up to 53° North in Russia, across all South-East Asia, down to Indonesia and the Philippines, and it was also introduced by the conquistadores into Latin America. It can affect a very large range of domestic and wild hosts including camelids, equines, cattle, buffaloes, sheep, goats, pigs, dogs and other carnivores, deer, gazelles, and elephants. It found a new large range of wild and domestic hosts in Latin America, including reservoirs (capybaras) and biological vectors (vampire bats). Surra is a major disease in camels, equines, and dogs, in which it can often be fatal in the absence of treatment, and exhibits nonspecific clinical signs (anaemia, loss of weight, abortion, and death), which are variable from one host and one place to another; however, its immunosuppressive effects interfering with intercurrent diseases or vaccination campaigns might be its most significant and questionable aspect.

Cancer in the parasitic protozoans Trypanosoma brucei and Toxoplasma gondii

“…Thus, spreading to other sites of the body can protect the parasite but may cause pathological damage. T. evansi, being an extracellular pathogen, freely ranges through the host and eventually resides extravascularly-usually in neurological tissue where it causes damage (82). T. evansi might be considered analogous to a freeliving cancer such as leukemia.…”

Insight into Trypanosomiasis in Animals: Various Approaches for its Diagnosis, Treatment and Control: A Review

“…Anim. Sci., 9 (5): 172-186, 2015 drugs could also be used (Desquesnes et al, 2013b). Melarsomine dihydrochloride is not recommended in buffaloes if treated with 0.75 mg kgG 1 body weight because chances of development of nervous signs.…”

A New PCR-RFLP for Species-Specific Diagnosis of South American Animal Trypanosomiasis

“…In Africa, this infection is caused by Trypanosoma congolense, T. vivax, T. evansi, T. simiae and T. brucei brucei. In South America, the absence of the cyclic vector (tsetse fly) has limited the number of species involved in the domestic ruminant sickness, with only T. vivax and T. evansi being identified (Desquesnes et al, 2013). T. theileri infection has also been reported in Africa and South America, however its pathogenicity in domestic large ruminants is still under study (Lee et al, 2013).…”