Epizootic Infection by Trypanosoma vivax in Cattle from the State of Minas Gerais, Brazil

Abstract

Trypanosomiasis is caused by a pathogenic protozoan of the genus Trypanosoma , being Trypanosoma vivax the most important agent for cattle. The aim of the present study was to demonstrate the expansion of T. vivax infection in different mesoregions of Minas Gerais, Brazil, and describe the clinicopathological findings of trypanosomiasis in cattle. The diagnosis was based on visualization of the parasite in blood smears and DNA detection of T. vivax in the blood of live cows and tissues of necropsied animals by the polymerase chain reaction (PCR). Thirty suspected herds were tested, of which 11 were positive for T. vivax . The most frequent clinical signs were anemia, apathy, drop in milk production, weight loss, reproductive disorders, and nervous signs. Concomitant diseases, such as malignant edema, pneumonia and increased cases of mastitis were associated with T. vivax infection. Three cows were necropsied and the most significant findings were low body condition score, pale mucous and spleen with white pulp hyperplasia. The results demonstrated the expansion of T. vivax infection in Minas Gerais, that PCR-associated blood smears are promising for diagnosis, and that other diseases often occur concomitantly to T. vivax infection in regions with trypanosomiasis in cattle.

Molecular epidemiological insights into Trypanosoma vivax in Argentina: From the endemic Gran Chaco to outbreaks in the Pampas

“…Diagnosis of T. vivax trypanosomosis should rely on highly sensitive and specific methods capable of detecting cryptically infected animals that can serve as healthy carriers, and to distinguish between T. vivax and T. evansi , which is also endemic in the Chaco (Monzón et al., 1995). Several PCR assays have successfully detected T. vivax in livestock from Brazil, Venezuela and Ecuador, including conventional PCR assays targeting cathepsin L genes (TviCATL‐PCR) (Chávez‐Larrea et al., 2020; Cortez et al., 2009; Fidelis Junior et al., 2019; Garcia et al., 2016; Reis et al., 2019) and LAMP (Cadioli et al., 2015; Fidelis Junior et al., 2019). We recently combined the species‐specific TviCATL‐PCR and a simplified fluorescent fragment length barcoding (FFLB) method followed by microsatellite analysis to detect and genotype T. vivax in cattle and buffaloes from lowlands of the Brazilian Amazonia.…”

“…Occasionally, the disease progresses to severe haematological and neurological disorders and can be fatal (Batista et al., 2007, 2009; Cadioli et al., 2012; Galiza et al., 2011). Progressive anaemia and weight loss, reproductive failure and a reduction in milk production are common in livestock chronically infected with T. vivax (Bastos et al., 2017; Betancur et al., 2016; Bittar et al., 2015; Costa et al., 2020; Garcia et al., 2016; Gonzatti et al., 2014; Reis et al., 2019; Rodrigues et al., 2013; Silva et al., 2013).…”

Mathematical modelling and control of African animal trypanosomosis with interacting populations in West Africa—Could biting flies be important in main taining the disease endemicity?

“…In this scenario, “tsetse-free” areas could have an abundance of biting flies (tabanids and stomoxyines) which could be contaminated with T. vivax from infected groups of wildlife species, small ruminants or infected cattle outside the treated zone. For instance, T. vivax has managed to maintain itself in South America where tsetse flies are absent, with Tabanidae and Stomoxys acting as mechanical vectors [ 42 ]. Similarly, Anene et al [ 7 ] observed that T. vivax was maintained in the flock by tabanids in tsetse-free areas in Nigeria.…”

Evaluation of techniques for diagnosis of Trypanosoma vivax infections in naturally infected cattle in the Zona da Mata Mineira

“…In Minas Gerais, the first report of T. vivax was in the municipality of Igarapé in 2007 (Carvalho et al, 2008). However, the disease has spread to other regions of the state (Cuglovici et al, 2010;Meneses, 2016;Reis et al, 2019). In one study, the estimated seroprevalence for the state was 2.38% and positive serological results were found in all mesoregions, including the Zona da Mata Mineira, with 1.67% of seroprevalence.…”

“…The main risk factors in the transmission of the agent in dairy cattle herds from Minas Gerais already reported involving the acquisition of animals without prior knowledge of their health status (Meneses, 2016), the presence of a population of hematophagous flies acting as mechanical vectors (Cuglovici et al, 2010) and needle sharing between animals, especially for the application of oxytocin (Reis et al, 2019).…”