Mapping risk of bovine fasciolosis in the south of Brazil using Geographic Information Systems

Fasciolosis, caused by Fasciola hepatica, is an endemic disease of ruminants that occurs in several countries of South America where it can lead to decreased production and fertility and, in severe cases, animal death. Although very prevalent, information on the epidemiology of the disease is incomplete in Brazil. The objective of the present study was to define the prevalence of F. hepatica in the livers of cattle from slaughterhouses and correlate the data with the animal's origin (climate and altitude) using a Geographic Information System (GIS). The data was used to create an epidemiological map of fasciolosis by state (Rio Grande do Sul, Santa Catarina, Paraná), by municipality (n=530) and by year (2003-2008). Information was analyzed using a databank from slaughterhouses with Federal Inspection Services of the Ministry of Agriculture. The highest cattle infection rate was found in the two most Southern states of Rio Grande do Sul (18.7%) and Santa Catarina (10.1%). Animals from the Campanha region of Rio Grande do Sul and from the central coast area of Santa Catarina had prevalences of greater than 40%. Cattle from low altitudes municipalities were significantly more likely to have the disease (p<0.05). No significant differences were found between high or low prevalence and ambient temperatures. Risk maps resulting from this study provide information on the epidemiology and transmission of F. hepatica in Southern Brazil needed for design of appropriate control measures to control economic impacts. F. hepatica may represent an important source of zoonotic infection of humans as well; therefore these findings may be complemented by future studies on human infections in high risk areas.