Epidemiological characteristics and risk factors in focal properties of equine infectious anemia in Rio Grande do Sul State, Brazil

Abstract

In Brazil, equine infectious anemia (EIA) infection is widespread in various regions,
with variable prevalence levels. The objective of this work was to determine the epidemiological
characteristics that could contribute to its dissemination on the western border of Rio Grande do
Sul, Brazil. To accomplish this, an epidemiological questionnaire was administered to equine owners
who had experienced EIA-positive animals on their properties from 2009 to 2019. The interviewees
were contacted via phone calls, and the questions aimed to identify patterns among properties, on
animal management, health, and owner’s knowledge about the infection. The primary information
was acquired from the data of the Official Veterinary Service (OVS) through data compilation and
tabulation of the official forms. Additionally, the same questionnaire was applied to properties without
records of the infection, as control. The results were analyzed using forward logistic regression to
explore potential risk associations. Out of a total of 123 focal properties, 28 interviews were completed,
six were interrupted or declined, 55 did not respond to phone calls, and 34 had outdated contact
information. Among the 30 control properties, 15 agreed to participate in the survey. The results
suggest that breeding, management, and sanitary control practices are Similar between focal and
control properties. Only two related risk factors could be distinguished for properties that have never
engaged in these practices, which were animal transit outside the property and contact with other
horses. In addition, it was observed that the official register is outdated for a significant number of
properties.