Seroepidemiological study of Equine Influenza in Some Provinces of Iran

Influenza is one of the most important equine respiratory diseases. Two subtypes of equine influenza virus A/equine-1 (H7N7) and A/equine-2 (H3N8) have been identified. This study was carried out to determine the seroprevalence of equine influenza virus in some provinces of Iran. Blood samples were taken from 290 horses and examined with haemagglutination (HI) test for detection antibodies against to two subtypes: H7N7 and H3N8. According to HI test, antibodies against to H3N8 were detected in 16(5.52%) horses; however, none of them had antibodies against to H7N7. The seroprevalence for H3N8 in the horses in Mazandaran, Hamadan, East Azerbaijan and Kermanshah, was 11.32%, 10.72%, 9.53% and 7.9%, respectively. Statistical analysis showed that there was no significant difference between infection with sex and age of horses. It is concluded that the horses of Iran are infected only with H3N8 and therefore, this should be considered in vaccination to equine influenza virus.