Equine Infectious Anemia: Active Surveillance in Central Italy 2007-2009

Equine infectious anemia (EIA) is an infectious and potentially fatal viral disease of equids. EIA virus is usually transmitted from horse to horse by large biting insects, such as horseflies. The aim of this study was to evaluate the results of a national surveillance plan from 2007 to 2009 and evaluate the potential risk factors of EIA in horse populations in central Italy. In 2007, 18 of 6,773; in 2008, 30 of 7,940; and in 2009, 21 of 11,666 equines tested were seropositive for EIA. No statistical association was found between location or sex and the diagnosis of EIA. The seroprevalence rate (2007-2008-2009) was higher among older equids (older than 6 years) than among young (3 months to 5 years old) (P < .05). Likewise, the seroprevalence rate (2007-2008-2009) was higher among mules than among other horses (P < .05). Until 2007, the national equine register did not exist in Italy; therefore, it was difficult to measure the percentage of untested horses that presented a real but unquantified risk for continued EIA virus transmission. By introducing new laws governing the control and conducting active surveillance for EIA, it has been possible, in Italy, to develop a firm foundation of knowledge concerning the persistence and transmission of EIA and the risk factors and to better control the spread of this infection in horses.