This cross-sectional study was designed to examine associations between exposure to EIV-infected horses and evidence of EIV infection in humans.
Employing informed consent, between October 2007 and April 2008, 100 subjects (89 with horse exposures and 11 non-exposed) were enrolled during equine events and at the University of the Sunshine Coast. All subjects provided a blood sample and were asked to complete an online questionnaire including health history, animal exposure and demographic information. Sera samples were tested for the presence of antibodies against two H3N8 EIV strains using microneutralization, hemagglutination inhibition, and enzyme-linked lectin assays.
Evidence for H3N8 infection was sparse, with only 9 study participants having any indication of H3N8 infection and the seroreactivity seen was low and easily explained by cross-reactions against human influenza strains or vaccines.
These data provide little evidence to support the premise that EIV infections occurred among humans exposed to EIV-infected horses during the 2007 Australian epizootic.