RESUMO
In Chile, while dog rabies has decreased markedly over the last 30 years, bat rabies is still reported frequently. In order to shed new light on the spatiotemporal trends of these reports, we analysed active and passive data from years 1985 and 2012, which included 61 076 samples from 289 counties of Chile. We found that from 1994 to 2012, more than 15 000 bat samples were submitted for diagnostics through passive surveillance, 9·5% of which tested positive for rabies. By contrast, the prevalence of infection was only ~0·4% among the nearly 12 000 bat samples submitted through active surveillance. We found that the prevalence of dog rabies dropped steadily over the same period, with just a single confirmed case since 1998. None of the 928 samples from wild animals, other than bats, were positive for rabies. Although there has been only one confirmed case of human rabies in Chile since 1985, and a single confirmed case in a dog since 1998, bats remain a reservoir for rabies viruses. While active surveillance indicates that rabies prevalence is low in bat colonies, the high proportion of positive bats submitted through passive surveillance is a concern. To prevent human rabies, local public health agencies should increase research on the basic ecology of bats and the role of stray dogs and cats as potential rabies amplifiers.
Assuntos
Quirópteros , Vírus da Raiva/isolamento & purificação , Raiva/epidemiologia , Animais , Chile/epidemiologia , Prevalência , Saúde Pública/tendências , Raiva/prevenção & controle , Raiva/transmissão , Raiva/virologia , Vírus da Raiva/classificação , Estações do Ano , Especificidade da Espécie , Fatores de TempoRESUMO
In Chile, dog rabies has been controlled and insectivorous bats have been identified as the main rabies reservoir. This study aimed to determine the rabies virus (RABV) variants circulating in the country between 2002 and 2008. A total of 612 RABV isolates were tested using a panel with eight monoclonal antibodies against the viral nucleoprotein (N-mAbs) for antigenic typing, and a product of 320-bp of the nucleoprotein gene was sequenced from 99 isolates. Typing of the isolates revealed six different antigenic variants but phylogenetic analysis identified four clusters associated with four different bat species. Tadarida brasiliensis bats were confirmed as the main reservoir. This methodology identified several independent rabies enzootics maintained by different species of insectivorous bats in Chile.
Assuntos
Quirópteros/virologia , Reservatórios de Doenças/virologia , Nucleoproteínas/imunologia , Vírus da Raiva/classificação , Raiva/virologia , Animais , Anticorpos Monoclonais , Anticorpos Antivirais , Gatos , Chile/epidemiologia , DNA Complementar , Reservatórios de Doenças/veterinária , Cães , Tipagem Molecular , Filogenia , RNA Viral/genética , Raiva/epidemiologia , Raiva/veterinária , Vírus da Raiva/genética , Vírus da Raiva/imunologia , Análise de Sequência de DNARESUMO
Forty-one isolates of rabies virus from insectivorous bats and one from a domestic cat in Chile, were characterized using eight anti-nucleoprotein monoclonal antibodies (N-Mabs) and by nucleotide sequence analysis. Thirty-two isolates were identified as antigenic variant 4 associated with Tadarida brasiliensis bats, twenty-eight were genetically associated with variant Tadarida brasiliensis and four with Lasiurus sp. bats. One isolate was identified as antigenic variant 3 associated with Desmodus rotundus bats, and by genetic analysis was identified as variant Myotis sp. bat. Eight isolates were unrelated to any antigenic variant, and they were identified as a genetic variant associated with Histiotus sp. bats. These antigenic and genetic characterizations may establish epidemiological links between rabies cases and increase the understanding of rabies epidemiology in this country.
Assuntos
Vírus da Raiva/classificação , Animais , Gatos , Chile , Quirópteros/virologia , Cães , Camundongos , Filogenia , Vírus da Raiva/genética , Vírus da Raiva/imunologiaRESUMO
One hundred and five rabies isolates obtained from domestic animals and insectivorous bats in Chile between 1977 and 1998 were molecularly characterized by limited sequence analysis of their nucleoprotein genes. These isolates were compared with viruses isolated from known domestic and wildlife rabies reservoirs in the Americas to identify potential reservoirs of rabies in Chile. The phylogenetic analyses showed that none of the Chilean isolates segregated with viruses from the terrestrial reservoirs. No non-rabies lyssaviruses were found in this study. The Chilean samples were not related to viruses of the sylvatic cycle maintained by the common vampire bat (Desmodus rotundus) in Latin America. Five genetic variants were identified from insectivorous bats in Chile. The Brazilian free-tailed bat (Tadarida brasiliensis) was identified as the reservoir for the rabies genetic variant most frequently isolated in the country between 1977 and 1998. The close association of a group of viruses obtained from a domestic dog (Canis familiaris), Brazilian free-tailed bats, and a red bat (Lasiurus borealis) with viruses maintained by Lasiurus spp. in North America implicated species of this genus as the possible reservoirs of this particular genetic variant in Chile. Reservoirs for the other three variants remain unknown.