Horses naturally infected by Trypanosoma vivax in southern Brazil

Abstract

In this study, we reported the first outbreak of the infection by Trypanosoma vivax in horses in southern Brazil, a non-endemic region where bovines have only recently been found infected by this trypanosome species. We evaluated 12 horses from a farm in southern Brazil, where four horses displayed pale mucous membranes, fever, weight loss, and swelling of abdomen, prepuce, or vulva. The diagnosis of T. vivax was confirmed in four horses by morphological parameters of trypomastigotes in blood smears and species-specific PCR. All T. vivax-infected animals showed anemia, and most showed increased levels of beta-1, beta-2, and gamma globulins. Horses were treated with diminazene aceturate, but cure was not achieved, and the disease relapsed after therapy. These findings demonstrated that Brazilian T. vivax isolates, which were already reported infecting cattle, buffaloes, goats, and sheep, can be highly pathogenic for horses, causing severe disease and even death of the animals due to the recurrence of the infection.

First report of Trypanosoma vivax outbreak in dairy cattle in São Paulo state, Brazil

“…However, in non-endemic areas, including Northeastern and Southeastern Brazil, where herds are immunologically naïve in relation to this hemoprotozoan, T. vivax has become a primary agent and can cause wasting disease and high levels of mortality (BATISTA et al, 2007DA SILVA et al, 2011). All of the abovementioned factors probably contributed towards increasing the rate of T. vivax transmission and were triggering factors for outbreak that we reported in this study.…”

“…This showed a 177 bp amplified DNA fragment, which confirmed the diagnosis of T. vivax infection (CORTEZ et al, 2009). Analyses on CatL-amplified sequences indicated that there was high genetic similarity among T. vivax isolates from Northern, Central and Southern Brazil that have been found circulating in cattle, water buffaloes, sheep, goats and horses (CORTEZ et al 2006(CORTEZ et al , 2009DA SILVA et al, 2011).…”

“…In the first T. vivax outbreak reported in the Northeastern region of Brazil, 130 dairy Holstein cows were found to be infected, and 11 of them died (BATISTA et al, 2007). In Brazil, mortality has only been shown to be common in cattle herds with no previous contact with T. vivax (BATISTA et al 2007;DA SILVA et al, 2009, 2011CUGLOVICI et al, 2010).…”

“…Anemia is the commonest find in cattle with clinical signs of T. vivax infection (SILVA et al, 1998b;BATISTA et al, 2007;OSÓRIO et al, 2008), sometimes associated with leukopenia (CARVALHO et al, 2008). In infections caused by trypanosomes, anemia has been attributed to bone marrow depletion and deposition of immune complexes on the erythrocyte surface, thus resulting in increased erythrophagocytosis, as well as to other factors such as enhanced neuraminidase and reduced cholinesterase activity and lipid peroxidation (MURRAY;DEXTER, 1998;DA SILVA et al, 2011). Elevated total protein levels were observed by Da Silva et al (2009) …”

“…Although outbreaks in cattle due to T. vivax may be sporadic in endemic areas of Brazil, especially in the Pantanal, recent reports have indicated that T. vivax is spreading across Brazil, thereby causing severe disease in cattle, sheep, goats and, more sporadically, in horses, in the Northeastern and Southern regions (BATISTA et al, 2007DA SILVA et al, 2009, 2011. Recently, the first outbreak of trypanosomiasis due to T. vivax in Southeastern Brazil, in the state of Minas Gerais, was reported by Cuglovici et al (2010).…”