Equine infectious anemia virus in naturally infected horses from the Brazilian Pantanal

Abstract

Equine infectious anemia (EIA) has a worldwide distribution, and is widespread in Brazil. The Brazilian Pantanal presents with high prevalence comprising equine performance and indirectly the livestock industry, since the horses are used for cattle management. Although EIA is routinely diagnosed by the agar gel immunodiffusion test (AGID), this serological assay has some limitations, so PCR-based detection methods have the potential to overcome these limitations and act as complementary tests to those currently used. Considering the limited number of equine infectious anemia virus (EIAV) sequences which are available in public databases and the great genome variability, studies of EIAV detection and characterization molecular remain important. In this study we detected EIAV proviral DNA from 23 peripheral blood mononuclear cell (PBMCs) samples of naturally infected horses from Brazilian Pantanal using a semi-nested-PCR (sn-PCR). The serological profile of the animals was also evaluated by AGID and ELISA for gp90 and p26. Furthermore, the EIAV PCR amplified DNA was sequenced and phylogenetically analyzed. Here we describe the first EIAV sequences of the 5' LTR of the tat gene in naturally infected horses from Brazil, which presented with 91% similarity to EIAV reference sequences. The Brazilian EIAV sequences also presented variable nucleotide similarities among themselves, ranging from 93,5% to 100%. Phylogenetic analysis showed that Brazilian EIAV sequences grouped in a separate clade relative to other reference sequences. Thus this molecular detection and characterization may provide information about EIAV circulation in Brazilian territories and improve phylogenetic inferences.

High Genomic Variability in Equine Infectious Anemia Virus Obtained from Naturally Infected Horses in Pantanal, Brazil: An Endemic Region Case

“…This report is the first to describe a complete EIAV genome from naturally infected Brazilian horses (field samples). Partial sequence of the 5 LTR/tat fragment was previously obtained from equids in the Pantanal region [23], and nucleotide sequences showed similarity from 93.5% to 100% with our sequences. Partial sequences of the Brazilian EIAV gag gene from Bahia are already available at NCBI (accession numbers: KC213776-KC213790) [44].…”

“…BRA1 was an asymptomatic viral carrier, and BRA2 presented oedema of low parts, high fever, and hypochlorous mucous membranes. Both animal samples were positive by semi-nested PCR with reverse transcription analysis [23], confirming the presence of viral RNA. Plasma was previously centrifuged at 8000× g for 10 min, and 200 µL of the pellet was used for RNA extraction with TRIzol LS Reagent (Invitrogen, Carlsbad, CA, USA) according to the manufacturer's instructions.…”

Phylogeography of equine infectious anemia virus

“…Phylogenetic relationships of EIAV have been previously assessed by the analysis of outbreak cases reported worldwide (Nagarajan and Simard, 2007; Cappelli et al, 2011; Capomaccio et al, 2012), mainly focused in the areas with high horse-related industry, such as Brazil (Bicout et al, 2006; Nogueira et al, 2017; Barzoni et al, 2018; Cursino et al, 2018). However, the evolutionary and spread history of EIAV is still unknown (Dorey-Robinson et al, 2019).…”

Doenças De Notificação Obrigatória De Relevância Em Equídeos No Brasil

“…Deve-se ressaltar que, o teste de ELISA deverá ser realizado apenas como triagem, e que todas as amostras positivas devem passar pelo teste de IDGA, e em casos onde houver divergência nos resultados entre os dois métodos, o resultado final obtido pelo teste de IDGA é o que deve permanecer (CURSINO et al, 2018).…”