Presence of Respiratory Viruses in Equines in Brazil

Abstract

Equines are susceptible to respiratory viruses such as influenza and parainfluenza. Respiratory diseases have adversely impacted economies all over the world. This study was intended to determine the presence of influenza and parainfluenza viruses in unvaccinated horses from some regions of the state of São Paulo, Brazil. Blood serum collected from 72 equines of different towns in this state was tested by hemagglutination inhibition test to detect antibodies for both viruses using the corresponding antigens. About 98.6% (71) and 97.2% (70) of the equines responded with antibody protective titers (≥ 80 HIU/25µL) H7N7 and H3N8 subtypes of influenza A viruses, respectively. All horses (72) also responded with protective titers (≥ 80) HIU/25µL against the parainfluenza virus. The difference between mean antibody titers to H7N7 and H3N8 subtypes of influenza A viruses was not statistically significant (p > 0.05). The mean titers for influenza and parainfluenza viruses, on the other hand, showed a statistically significant difference (p < 0.001). These results indicate a better antibody response from equines to parainfluenza 3 virus than to the equine influenza viruses. No statistically significant differences in the responses against H7N7 and H3N8 subtypes of influenza A and parainfluenza 3 viruses were observed according to the gender (female, male) or the age (≤ 2 to 20 years-old) groups. This study provides evidence of the concomitant presence of two subtypes of the equine influenza A (H7N7 and H3N8) viruses and the parainfluenza 3 virus in equines in Brazil. Thus, it is advisable to vaccinate equines against these respiratory viruses.

Seroprevalence of viral agents in vaquejada horses

“…In this study, the prevalence of antibodies against EI type H3N8 was 55.74%, higher than that found by Heinemann et al (2009) in Pará (76.5%) and Mancini et al (2014), who reported a prevalence of 97.2% of antibodies against H3N8 in São Paulo; Oliveira et al (2005) reported a prevalence of 35.9% in Rio de Janeiro. These high indexes suggest the ease of transmission of the virus in equine populations, mainly where there is agglomeration of animals and EI transmission occurs through the respiratory route.…”

Equine influenza in Brazil

“…In Brazil, H7 antibodies have also been reported by different authors (PAGANO et al, 1985;MANCINI et al, 2004;AGUIAR et al, 2008;HEINEMANN et al, 2009;CUNHA et al, 2009;FILIPPSEN, 2013;MANCINI et al, 2014) with positive results and frequencies of between 2.7% to 98.6%. (FILIPPSEN, 2013).…”

“…In Brazil, simultaneous detection of HI antibodies against the H3N8 and H7N7 subtypes of EIV has been described since 1985(PAGANO et al, 1985MANCINI et al, 2004;AGUIAR et al, 2008;HEINEMANN et al, 2009;CUNHA et al, 2009;FILIPPSEN, 2013;MANCINI et al, 2014). Among these studies, only in Rondônia (AGUIAR et al, 2008), Pará (HEINEMANN et al, 2009) (MANCINI et al, 2014).…”

Comparison among three different serological methods for the detection of equine influenza virus infection

“…In Brazil, antibodies against H7N7 have also been reported (26,31,32,33,37), with frequencies between 2.7% and 77.75%. The ELISA and HI in general have higher ASen than AGID, while AGID has usually higher DSpe than ELISA or HI.…”