West Nile virus Epidemic in Horses, Tuscany Region, Italy

• DOI: 10.3201/eid0812.020234
• Publication Date: 2012-06-22T22:14:23Z
• Authors: Gian Luca Autorino; Antonio Battisti; Vincent Deubel; Giancarlo Ferrari; Riccardo Forletta; Armando Giovannini; Rossella Lelli; Severine Murri; Maria Teresa Scic...
• Keywords: Research; R; Infectious and parasitic diseases; RC109-216; 04 agricultural and veterinary sciences; 6. Clean water; Disease Outbreaks; 3. Good health; 0403 veterinary science; Italy; Seroepidemiologic Studies; Medicine; Animals; Horse Diseases; Horses; West Nile virus; West Nile Fever; Retrospective Studies

During the late summer of 1998, veterinary authorities in Tuscany, Italy, received reports of cases of neurologic disease among horses residing in a large wetland area located in the provinces of Florence and Pistoia. West Nile virus was isolated from two of the six horses that died or were euthanized. A retrospective epidemiologic study identified 14 clinical neurologic cases that occurred from August 20 to October 6 (attack rate of 2.8%). A serologic survey conducted over a 700-km2 area in stables with and without apparent clinical cases confirmed a wider spread of the infection, with an overall seroprevalence rate of 38% in the affected area. No significant differences in age-specific prevalence were observed, suggesting that the horses residing in the area had not been exposed previously to West Nile virus and supporting the hypothesis of its introduction in the wetland area during the first half of 1998.