Role of insectivorous bats in the transmission of Rabies in Chile

The importance of wild animals in the epidemiology of rabies in Chile was n ot recognized until 1985. Since then the epidemiology of rabies has been ch aracterized by the presence of an endemic cycle in the species of the Order Chiroptera. In 1996, after 24 years without human rabies cases, a child di ed of the disease. The victim was infected with an antigenic variant 4 (AgV 4) virus whose reservoir is the non-hematophagous bats Tadarida brasiliensi s. This event emphatized the need for a better characterization of rabies s elvatic cycles, their geographical distribution, and the risk factors that influence the virus transmission to humans and domestic animals in the coun try. From a total of 250 isolates obtained between 1977 and 1997, 119 were react ived. These samples were antigenically characterized by the indirect inmuno fluorescence technique using a panel of 8 monoclonal antibodies direct agai nst epitopes of the viral nucleoprotein produced by the Centers of Disease Control and Prevention, Atlanta, Georgia, USA. The analysis showed that all the viruses obtained from non-hematophagous bats were AgV4 seven out of 10 canine isolates were AgV4. The other 3 canine viruses were AgV1, whose res ervoir is the dog. Of the 3 bovine isolates, 2 was AgV1 and 1 AgV4. Three f eline and one porcine viruses was caracterized as AgV4. it was determined t hat a bovine rabies case reported in 1977 and all the viruses isolated from domestic animals since 1990 were AgV4. These results allowed to conclude that, in Chile, the non-hematophagous bat s Tadarida brasiliensis was a rabies selvatic reservoir before 1985, and si nce then it has been the only wild reservoir know responsible for rabies sp oradic cases in human and domestic animals.