Reproductive failures associated with Trypanosoma (Duttonella) vivax.

Trypanosomosis is a disease of a high economic impact in different productive livestock systems, especially in Africa and South America; cattle, sheep, goats, horses and donkeys can be prone to infection. Trypanosoma vivax is a blood parasite normally associated with a case of anemia and persistent febrile status, which causes a reduction in production, weakness of affected animals and occasionally death. However, the reproductive disorders which include abortion, disruption of the estrous cycle, placental retention, perinatal mortality, among others, can be very severe, especially when they occur during the last third of gestation. In addition, the transplacental transmission has been proved in this agent with serious consequences in the fetus. Additionally, the infection reduces the fertilizing capacity of the spermatozoa by degenerative effects at a testicular and epididymal level. These reproductive alterations can lead to temporal or permanent infertility problems and in some cases to sterility. The capacity of T. vivax to evade the host's immune system, allows it to persist in animals for months or years. The development of diagnostic tools is very important in order to increase the sensibility and specificity in parasite detection, but it is of paramount importance to prepare field professionals to consider this agent in the differential diagnosis of reproductive failure. The rational and strategic use of the therapeutic drugs will enable to use them in the future, thus avoiding resistance problems.
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