Epidemiology of rabies in large animals of Parana, Brazil, from 1977 to 2012

ABSTRACT:

A descriptive epidemiological survey of rabies in herbivorous reared in the state of Parana, Brazil, was carried out from 1977 to 2012. The positive cases and the total number of brain samples processed for diagnostic purposes were distributed according to species, year, month, geographical region and municipality. Chi-square test was used to verify if rabies was associated to these factors. Probabilistic model was applied to historical series in order to verify cyclic and seasonal patterns. In Parana, rabies is an endemic disease with variable yearly occurrence, without seasonal pattern and with a possible cyclic pattern every 18 years. Cattle (86.9%) and equides (11.3%) were mainly affected. Rabies was registered in 47.6% of all municipalities, indicating a great spread of this disease in Parana, mainly during the last decade. Middlewest and Curitiba regions, followed by Pioneer North and West regions, were the areas of most occurrence. The number of cases per municipality was weakly correlated with the number of shelters for Desmodus rotundus (r=0.469; p<0.0001). Therefore, we suggest that annual immunization of cattle and equides should be applied in the high occurrence areas (Middlewest and Curitiba regions) and encouraged in intermediate occurrence areas (Pioneer North and West regions).

INDEX TERMS:
Epidemiology; rabies; Parana; Brazil; Lyssavirus; encephalitis; cattle; equids; mortality.