First description of Theiler's disease-associated virus infection and epidemiological investigation of equine pegivirus and equine hepacivirus coinfection in Brazil.
Transbound Emerg Dis
; 66(4): 1737-1751, 2019 Jul.
Article
em En
| MEDLINE
| ID: mdl-31017727
ABSTRACT
Recent advances in the study of equine pegivirus (EPgV), Theiler's disease-associated virus (TDAV) and equine hepacivirus (EqHV) highlight their importance to veterinary and human health. To gain some insight into virus distribution, possible risk factors, presence of liver damage and genetic variability of these viruses in Brazil, we performed a cross-sectional study of EPgV and TDAV infections using a simultaneous detection assay, and assessed EqHV coinfection in different horse cohorts. Of the 500 serum samples screened, TDAV, EPgV and EPgV-EqHV were present in 1.6%, 14.2% and 18.3%, respectively. EPgV-positive horses were present in four Brazilian states Espírito Santo, Mato Grosso do Sul, Minas Gerais and Rio de Janeiro. Serum biochemical alterations were present in 40.4% of EPgV-infected horses, two of them presenting current liver injury. Chance of infection was 2.7 times higher in horses ≤5 years old (p = 0.0008) and 4.9 times higher in horses raised under intensive production systems (p = 0.0009). EPgV-EqHV coinfection was 75% less likely in horses older than 5 years comparatively to those with ≤5 years old (p = 0.047). TDAV-positive animals were detected in different horse categories without biochemical alteration. Nucleotide sequences were highly conserved among isolates from this study and previous field and commercial product isolates (≥88% identity). Tree topology revealed the formation of two clades (pp = 1) for both EPgV and TDAV NS3 partial sequences. In conclusion, the widespread presence of EPgV-RNA suggests an enzootic infection with subclinical viremia in Brazil. Horse management can influence virus spread. This first report of TDAV-infected horses outside the USA reveals the existence of subclinical viremic horses in distant geographical regions. EPgV and TDAV have similar circulating isolates worldwide. These findings contribute to global efforts to understand the epidemiology and pathogenesis of these equine viruses.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Infecções por Flaviviridae
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Flaviviridae
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Coinfecção
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Doenças dos Cavalos
Tipo de estudo:
Etiology_studies
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Observational_studies
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Prevalence_studies
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Risk_factors_studies
Limite:
Animals
País/Região como assunto:
America do sul
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Brasil
Idioma:
En
Revista:
Transbound Emerg Dis
Ano de publicação:
2019
Tipo de documento:
Article