SUMMARYAnimal and human rabies samples isolated between 1989 and 2000 were typified by means of a monoclonal antibody panel against the viral nucleoprotein. The panel had been previously established to study the molecular epidemiology of rabies virus in the Americas. Samples were isolated in the Diagnostic Laboratory of the Pasteur Institute and in other rabies diagnostic centers in Brazil. In addition to the fixed virus samples CVS-31/96-IP, preserved in mouse brain, and PV-BHK/97, preserved in cell culture, a total of 330 rabies virus samples were isolated from dogs, cats, cattle, horses, bats, sheep, goat, swine, foxes, marmosets, coati and humans. Six antigenic variants that were compatible with the pre-established monoclonal antibodies panel were defined: numbers 2 (dog), 3 (Desmodus rotundus), 4 (Tadarida brasiliensis), 5 (vampire bat from Venezuela), 6 (Lasiurus cinereus) and Lab (reacted to all used antibodies). Six unknown profiles, not compatible with the panel, were also found. Samples isolated from insectivore bats showed the greatest variability and the most commonly isolated variant was variant-3 (Desmodus rotundus). These findings may be related to the existence of multiple independent transmission cycles, involving different bat species.

ABSTRACT. A molecular epidemiological analysis was performed in 19 rabies viruses (RVs) isolated from haematophagous, frugivorous and insectivorous bats, in Sao Paulo, Brazil. The authors carried out RT-PCR for amplification of the RV nucleoprotein (N) gene, and determined 1,335 nucleotide sequences of N gene by direct sequencing method. Phylogenetic analysis, which was based on the N gene of Brazilian RV isolates identified presently and previously, revealed that RVs isolated from bats were genetically divided into four lineages had a tendency to depend on the host bat species. Rabies viruses (RVs) isolated in Brazil belong to genotype 1 of genus lyssavirus, family Rhabdoviridae. Ito et al. [7,8] reported that main reservoirs of RVs were dogs and vampire bats and that the RVs were classified into dogrelated RVs and vampire bat-related RVs in Brazil. In some areas of Brazil, the rabies outbreaks by both dog-and batrelated RVs occurred at the same time [7]. RVs have been isolated from not only haematophagous bats but also frugivorous and insectivorous bats in Brazil. In Argentina, RVs isolated from frugivorous bats (Artibeus lituratus) were identified to be the variant of RV associated with haematophagous bats by use of the monoclonal antibody panels [4]. Recently we have demonstrated that RVs isolated from Brazilian frugivorous bats (Artibeus spp.) were phylogenetically characterized as the vampire bat-related RV [18].There are many reports of human cases on infection with insectivorous bat RVs, and the number of the cases tend to increase in North America [10][11][12]. In 2002, Favi et al. [5] reported that insectivorous bat (Tadarida brasiliensis) RV variant was isolated from a human patient in Chile. In Colombia and Venezuela insectivorous bat RV variants were also isolated from dogs and cats, which were main RVtransmitters to human [2,14]. Although some kinds of insectivorous bats have been diagnosed as RV-positive in Brazil, there have been no reports of the human case on infection with insectivorous bat RV variants until now. RVpositive insectivorous bats were, however, found in urban areas, and this fact has been considered as important problems in public health [1,6,17,21].As there is little information about the genetic characteristics of bat-related RVs in Brazil, authors determined nucleotide sequences on the N gene of RVs isolated from 9 Brazilian bat species. Phylogenetic analysis was also performed for the epidemiological study with the isolates identified previously. MATERIALS AND METHODS Viruses:In this study, 19 RVs were isolated from 3 haematophagous bats (Desmodus rotundus), 1 frugivorous bat (Artibeus lituratus), 13 insectivorous bats (3 Nyctinomops laticaudatus, 2 Eumops auripendulus, 4 Eptesicus furinalis, 2 Molossus molossus, 1 Molossus abrasus and 1 Molossus rufus) and 2 unclassified bats, and their nucleoprotein gene sequences were determined. Brain materials from these bats were diagnosed as RV-positive by immunofluorescent antibody test (FAT) using a rabbit polyclonal anti-rabies nucle...

WNV circulation is confirmed by this large scale survey even in the absence of detection of clinical cases.

Rabies laboratory diagnosis is performed by using microscopic examination for Negri bodies (MEN), fluorescent-antibody test (FAT) and mouse inoculation test (MIT). In the majority of cases, when specimens are properly collected and conserved and the laboratory worker has good experience, agreement among employed techniques is verified. Comparing the sensitivity of these three diagnosis techniques in 3,713 samples (hippocampus and brain stem) received during 1981-1994 period, being 3,010 from bovine (983 positives) and 703 from equine (111 positives) species, it was observed that in equine rabid samples, this agreement was not maintained. For the latter specie, only in few opportunities the Negri bodies could be observed. With respect to FAT, the test detected a lower porcentage of positive equine samples compared to bovine species. Statistical analysis demonstrated that the difference was significative. Mouse inoculation test proved to be more sensitive. However, a significant difference in mice incubation period was observed for samples from both species. The absence of inclusion bodies and the longer incubation period for equine samples suggest that rabies pathogenesis studies for equine species have to be intensified.

OBJECTIVE:Reports on bat rabies in Brazil are sporadic and isolated. This study aimed at describing the detection of rabies virus in bats in the state of São Paulo. METHODS:A total of 7,393 bats from 235 municipalities of the north and northwestern areas of the state of São Paulo, Southeastern Brazil, were assessed according to their morphological and morphometric characteristics from 1997 to 2002. Fluorescent antibody test and mice inoculation were used for viral identification. RESULTS:Of all samples examined, 1.3% was rabies virus positive, ranging from 0.2% in 1997 to 1.6% in 2001. There were found 98 bats infected, 87 in the urban area. Fluorescent antibody test was detected in 77 positive samples, whereas 92 produced rabies signs in mice; incubation period ranging from 4 to 23 days. In 43 cities at least one rabid bat was observed. The highest proportion (33.7%) of rabies virus was found in Artibeus lituratus. Eptesicus and Myotis were the most frequent positive species (24.5%) of the Vespertilionidae family. The species Molossus molossus and Molossus rufus showed 14.3% positive bats. There were no differences in the distribution of positive rabies between females (33; 48.5%) and males (35; 51.5%). CONCLUSIONS:Rabies-infected bats were found in environments that pose a risk to both human and domestic animal population and there is a need for actions aiming at the control of these species and public education. KEYWORDS

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