Rabies surveillance in bats in Northwestern State of São Paulo

Introduction Rabies is an important zoonosis that occurs in mammals, with bats acting as Lyssavirus reservoirs in urban, rural and natural areas. Rabies cases in bats have been recorded primarily in urban areas in Northwestern State of São Paulo since 1998. This study investigated the circulation of rabies virus by seeking to identify the virus in the brain in several species of bats in this region and by measuring rabies-virus neutralizing antibody levels in the hematophagous bat Desmodus rotundus. Methods From 2008 to 2012, 1,490 bat brain samples were sent to the Universidade Estadual Paulista (UNESP) Rabies Laboratory in Araçatuba, and 125 serum samples from vampire bats that were captured in this geographical region were analyzed. Results Rabies virus was detected in the brains of 26 (2%) of 1,314 non-hematophagous bats using the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). None of the 176 hematophagous bat samples were positive for rabies virus when a virus detection test was utilized. Out of 125 vampire bat serum samples, 9 (7%) had levels of rabies virus neutralization antibodies (RVNAs) that were higher than 0.5IU/mL; 65% (81/125) had titers between 0.10IU/mL and 0.5IU/mL; and 28% (35/125) were negative for RVNAs using the simplified fluorescent inhibition ...

Rabies surveillance in bats in Northwestern State of São Paulo.

Introduction Rabies is an important zoonosis that occurs in mammals, with bats acting as Lyssavirus reservoirs in urban, rural and natural areas. Rabies cases in bats have been recorded primarily in urban areas in Northwestern State of São Paulo since 1998. This study investigated the circulation of rabies virus by seeking to identify the virus in the brain in several species of bats in this region and by measuring rabies-virus neutralizing antibody levels in the hematophagous bat Desmodus rotundus. Methods From 2008 to 2012, 1,490 bat brain samples were sent to the Universidade Estadual Paulista (UNESP) Rabies Laboratory in Araçatuba, and 125 serum samples from vampire bats that were captured in this geographical region were analyzed. Results Rabies virus was detected in the brains of 26 (2%) of 1,314 non-hematophagous bats using the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). None of the 176 hematophagous bat samples were positive for rabies virus when a virus detection test was utilized. Out of 125 vampire bat serum samples, 9 (7%) had levels of rabies virus neutralization antibodies (RVNAs) that were higher than 0.5IU/mL; 65% (81/125) had titers between 0.10IU/mL and 0.5IU/mL; and 28% (35/125) were negative for RVNAs using the simplified fluorescent inhibition microtest (SFIMT) in BHK21 cells. The observed positivity rate (1.7%) was higher than the average positivity rate of 1.3% that was previously found in this region. Conclusions The high percentage of vampire bats with neutralizing antibodies suggests that recent rabies virus exposure has occurred, indicating the necessity of surveillance measures in nearby regions that are at risk to avoid diffusion of the rabies virus and possible rabies occurrences.

Humoral immune response in dogs and cats vaccinated against rabies in southeastern Brazil.

BACKGROUND: Brazil holds annual nationwide public campaigns to vaccinate dogs and cats against rabies. The presence of rabies antibodies in these animals, which are among the main transmitters of rabies to humans, is a good indicator that they are immunized and protected. METHODS: In the present study we analyzed 834 serum samples from dogs and cats from the Southeast of Brazil (Presidente Prudente and Dracena cities), 12 months after the 2009 vaccination campaign. We used the technique known as rapid fluorescent focus inhibition test (RFFIT) and considered reactant those sera with values higher 0.5 IU/mL. RESULTS AND DISCUSSION: Reactant sample results in Presidente Prudente were 153 (51.0%) for dogs and 59 (32.6%) for cats, and in Dracena 110 (52.1%) for dogs and 71 (50.0%) for cats. We discussed vaccine coverage of animals involved in this experiment, and observed low titers < 0.5 IU/mL, especially in cats from Presidente Prudente. CONCLUSION: According to the results presented in our experiment, we suggest that titers below 0.5 IU/mL are worrisome and that, for multiple reasons, animals should be immunized against rabies in the period between public vaccination campaigns. Hence, the desired vaccine coverage was not accomplished, especially among cats from Presidente Prudente.

Humoral immune response in dogs and cats vaccinated against rabies in southeastern Brazil

Brazil holds annual nationwide public campaigns to vaccinate dogs and cats against rabies. The presence of rabies antibodies in these animals, which are among the main transmitters of rabies to humans, is a good indicator that they are immunized and protected.Methods In the present study we analyzed 834 serum samples from dogs and cats from the Southeast of Brazil (Presidente Prudente and Dracena cities), 12 months after the 2009 vaccination campaign. We used the technique known as rapid fluorescent focus inhibition test (RFFIT) and considered reactant those sera with values higher 0.5 IU/mL. Results and discussion Reactant sample results in Presidente Prudente were 153 (51.0%) for dogs and 59 (32.6%) for cats, and in Dracena 110 (52.1%) for dogs and 71 (50.0%) for cats. We discussed vaccine coverage of animals involved in this experiment, and observed low titers < 0.5 IU/mL, especially in cats from Presidente Prudente.Conclusion According to the results presented in our experiment, we suggest that titers below 0.5 IU/mL are worrisome and that, for multiple reasons, animals should be immunized against rabies in the period between public vaccination campaigns. Hence, the desired vaccine coverage was not accomplished, especially among cats from Presidente Prudente.

Humoral immune response in dogs and cats vaccinated against rabies in southeastern Brazil

Background: Brazil holds annual nationwide public campaigns to vaccinate dogs and cats against rabies. The presence of rabies antibodies in these animals, which are among the main transmitters of rabies to humans, is a good indicator that they are immunized and protected. Methods: In the present study we analyzed 834 serum samples from dogs and cats from the Southeast of Brazil (Presidente Prudente and Dracena cities), 12 months after the 2009 vaccination campaign. We used the technique known as rapid fluorescent focus inhibition test (RFFIT) and considered reactant those sera with values higher 0.5 IU/mL. Results and discussion: Reactant sample results in Presidente Prudente were 153 (51.0%) for dogs and 59 (32.6%) for cats, and in Dracena 110 (52.1%) for dogs and 71 (50.0%) for cats. We discussed vaccine coverage of animals involved in this experiment, and observed low titers < 0.5 IU/mL, especially in cats from Presidente Prudente. Conclusion: According to the results presented in our experiment, we suggest that titers below 0.5 IU/mL are worrisome and that, for multiple reasons, animals should be immunized against rabies in the period between public vaccination campaigns. Hence, the desired vaccine coverage was not accomplished, especially among cats from Presidente Prudente.

Molecular characterization of rabies virus isolated from non-haematophagous bats in Brazil / Caracterização molecular do vírus da raiva isolado de morcegos não-hematófagos no Brasil

INTRODUCTION: Rabies is an important zoonosis that causes thousands of deaths worldwide each year. Although the terrestrial cycle, mainly transmitted by dogs, is controlled in Brazil, the aerial cycle remains a serious public health issue, besides the economic problem. In the aerial cycle, the haematophagous bat Desmodus rotundus is the main source of infection, where several different species of non-haematophagous bats can be infected and can transmit the virus. METHODS: The aim of this work was to study the epidemiological pattern of rabies using antigenic characterization with monoclonal antibodies and genetic characterization by reverse-transcriptase polymerase chain reaction followed by sequencing and phylogenetic analysis of non-haematophagous bats' and herbivorous animals' central nervous system samples from the western region of the State of São Paulo, Brazil. RESULTS: From 27 samples, 3 antigenic variants were identified: AgV-3, AgV-4, and AgV-6; and from 29 samples, 5 different clusters were identified, all belonging to the rabies virus species. CONCLUSIONS: Although only non-haematophagous bats were evaluated in the studied region, the majority of samples were from antigenic and genetic variants related to haematophagous bats Desmodus rotundus. Samples from the same antigenic variant were segregated in more than one genetic cluster. This study demonstrated the diversity of rabies virus genetic lineages presented and circulating in non-haematophagous bats in the studied region.

INTRODUÇÃO: A raiva é uma importante zoonose responsável por milhares de mortes anualmente em todo o mundo. Embora o ciclo silvestre, onde os cães são os principais transmissores esteja controlado no Brasil, o ciclo aéreo, onde o morcego hematófago Desmodus rotundus é o principal transmissor e diversas espécies de morcegos não hematófagos podem se infectar e transmitir o vírus, permanence como um importante problema econômico e de saúde pública. MÉTODOS: O objetivo deste trabalho foi a caracterização antigênica por meio da utilização de anticorpos monoclonais e a caracterização genética por meio da reação em cadeia pela polimerase pela transcriptase reversa seguida de análise filogenética em morcegos não hematófagos e animais domésticos herbívoros provenientes da região oeste do Estado de São Paulo. RESULTADOS: A análise antigênica de 27 amostras determinou três variantes distintas: Agv-3, AgV-4 e AgV-6; a análise genética de 29 amostras identificou 5 diferentes grupos, todos pertencentes a espécie Rabies virus. CONCLUSÕES: Ainda que apenas amostras de morcegos não hematófagos tenham sido analisadas, a maioria das variantes antigênicas e genéticas identificadas na região estava relacionada com a variante mantida pelos morcegos hematófagos Desmodus rotundus. Amostras de uma mesma variante antigênica segregaram em mais de um clado genético. Este estudo demonstrou a diversidade de linhagens genéticas do vírus da raiva presentes e circulantes em morcegos não hematófagos na região estudada.

[The bats and rabies in the Western region of the State of São Paulo, Brazil]. / Os morcegos e a raiva na região oeste do Estado de São Paulo.

INTRODUCTION: The Polo da Alta Sorocabana Laboratory in Presidente Prudente, SP, in partnership with other research institutions, conducted studies related to bats from the western region of the State of Sao Paulo, Brazil. Thus, certain situations were investigated, including: a) isolation of the rabies virus from 2006 to 2008; b) identification of respective antigenic variants; and c) characterization of daytime shelters of Desmodus rotundus vampire bats. METHODS: Samples for examination originated from nonhematophagous bats forwarded to the laboratory and subjected to direct fluorescent antibody test and mouse inoculation test. Positive samples were characterized by the monoclonal antibody test. Regarding the bats, they were identified and classified and mapping of their shelters was also performed. RESULTS: The laboratory received 1,113 nonhematophagous bats for rabies diagnosis, 11 (1%) of which were positives, and among the positive samples, 5 (45.5%) presented antigenic variant 3 (from the bat Desmodus rotundus) and 4 (36.5%) were compatible with samples derived from Brazilian insectivorous bats. Sixteen vampire bat shelters were investigated and observation confirmed the presence of another 3 species of nonhematophagous bats coexisting with them. CONCLUSIONS: The experiments showed that at least 3 antigenic variants of rabies virus are circulating in the region and that the cohabitation of vampire bats with nonhematophagous bats could be related to the dissemination of the rabies virus.

Os morcegos e a raiva na região oeste do Estado de São Paulo / The bats and rabies in the Western region of the State of São Paulo, Brazil

INTRODUÇÃO: O laboratório do Pólo da Alta Sorocabana de Presidente Prudente, SP, em parceria com outras instituições de pesquisa, realizou estudos pertinentes aos morcegos da região oeste do Estado de São Paulo, Brasil. Para tal, foram pesquisadas algumas situações, tais como: a) isolamento do vírus rábico, no período 2006 a 2008; b) as respectivas variantes antigênicas; c) abrigos diurnos do morcego hematófago Desmodus rotundus. MÉTODOS: As amostras para exame foram provenientes de morcegos não hematófagos encaminhadas ao laboratório sendo submetidas aos testes de imunofluorescência direta e prova biológica. As amostras positivas foram caracterizadas antigenicamente por meio do teste de anticorpos monoclonais. Quanto aos morcegos, foram identificados e classificados, e também foi realizado mapeamento de abrigos dos mesmos. RESULTADOS: O laboratório recebeu 1.113 morcegos não hematófagos para diagnóstico laboratorial, sendo 11 (1 por cento) deles positivos, e dentre as amostras positivas, 5 (45,5 por cento) delas tiveram variante antigênica 3 associada ao morcego D. rotundus e 4 (36,5 por cento) foram compatíveis com amostras de morcegos insetívoros. Foram pesquisados 16 abrigos de morcegos hematófagos e observou-se a presença de outras 3 espécies de morcegos não hematófagos convivendo com eles. CONCLUSÕES: Os experimentos mostraram que o vírus rábico continua circulando na região com pelo menos 3 variantes antigênicas, e que, a coabitação de morcegos hematófagos com não hematófagos pode ter alguma relação com a disseminação do vírus rábico.

INTRODUCTION: The Polo da Alta Sorocabana Laboratory in Presidente Prudente, SP, in partnership with other research institutions, conducted studies related to bats from the western region of the State of Sao Paulo, Brazil. Thus, certain situations were investigated, including: a) isolation of the rabies virus from 2006 to 2008; b) identification of respective antigenic variants; and c) characterization of daytime shelters of Desmodus rotundus vampire bats. METHODS: Samples for examination originated from nonhematophagous bats forwarded to the laboratory and subjected to direct fluorescent antibody test and mouse inoculation test. Positive samples were characterized by the monoclonal antibody test. Regarding the bats, they were identified and classified and mapping of their shelters was also performed. RESULTS: The laboratory received 1,113 nonhematophagous bats for rabies diagnosis, 11 (1 percent) of which were positives, and among the positive samples, 5 (45.5 percent) presented antigenic variant 3 (from the bat Desmodus rotundus) and 4 (36.5 percent) were compatible with samples derived from Brazilian insectivorous bats. Sixteen vampire bat shelters were investigated and observation confirmed the presence of another 3 species of nonhematophagous bats coexisting with them. CONCLUSIONS: The experiments showed that at least 3 antigenic variants of rabies virus are circulating in the region and that the cohabitation of vampire bats with nonhematophagous bats could be related to the dissemination of the rabies virus.

Molecular characterization of rabies virus isolated from non-haematophagous bats in Brazil.

INTRODUCTION: Rabies is an important zoonosis that causes thousands of deaths worldwide each year. Although the terrestrial cycle, mainly transmitted by dogs, is controlled in Brazil, the aerial cycle remains a serious public health issue, besides the economic problem. In the aerial cycle, the haematophagous bat Desmodus rotundus is the main source of infection, where several different species of non-haematophagous bats can be infected and can transmit the virus. METHODS: The aim of this work was to study the epidemiological pattern of rabies using antigenic characterization with monoclonal antibodies and genetic characterization by reverse-transcriptase polymerase chain reaction followed by sequencing and phylogenetic analysis of non-haematophagous bats' and herbivorous animals' central nervous system samples from the western region of the State of São Paulo, Brazil. RESULTS: From 27 samples, 3 antigenic variants were identified: AgV-3, AgV-4, and AgV-6; and from 29 samples, 5 different clusters were identified, all belonging to the rabies virus species. CONCLUSIONS: Although only non-haematophagous bats were evaluated in the studied region, the majority of samples were from antigenic and genetic variants related to haematophagous bats Desmodus rotundus. Samples from the same antigenic variant were segregated in more than one genetic cluster. This study demonstrated the diversity of rabies virus genetic lineages presented and circulating in non-haematophagous bats in the studied region.

Multiple substitutions in biologically active domains ofrabies virus glycoprotein can be related to pathogenicprofile / Múltiplas substituições em domínios biologicamente ativos da glicoproteína do vírusrábico podem estar relacionadas com o perfil patogênico

Pathogenic profile of a rabies virus isolated from an insectivorous bat Lasiurus ega was compared with a rabies fixedvirus strain (CVS/32) in hamster and mouse. Incubation and clinical periods, clinical manifestation and death rateswere compared. Challenge of hamsters with L. ega was performed using: 10 2,611-4,021 LD50 /0,05 mL;. For CVS were used10 3,7-4,7 LD50 /0,05 mL. Were tested intramuscular (IM), intradermal (ID), intranasal (IN), epidermal abrasion (EA)inoculation routes. Viral antigen in brains was confirmed by Direct Immunofluorescence Test. Mortality percentagesobserved with L. ega rabies virus isolate were the following in hamster: 3,5 % IM, 10,710% IN; in mice: 50.0% IM, 30.0%IN. Furious rabies was predominant. Mortality percentages observed with CVS/32 in hamster: 12.5% IM, 62.5% ID,12.5% IN; in mice 100.0% IM, 70.0% ID, 10.0% IN. Paralytic rabies was found with this strain in both animal models.Epidermic abrasion was not a suitable challenge route. Incubation period was 5-7 days for CVS and 11-16 days for L. egaisolate, meanwhile clinical periods were comprehended between 4–7 days for both viruses. Several substitutions weredetected at antigenic domains of glycoprotein: AI (position 231), AII (34–42 and 198-200), domain of fusion dependenton low pH (102–179), transmembrane domain (440–461) and residue 242. These viruses showed contrasting biologicalbehaviors that can be linked to those substitutions at antigenic domains previously described.

O perfil patogênico de um vírus da raiva isolado de um morcego insetívoro Lasiurus ega foi comparado com o de vírusfixo de raiva (CVS/32) em hamster e camundongo, determinando os períodos de incubação e clínico, manifestaçãoclínica e mortalidade. Os animais foram desafiados com 10 2,611 - 4,021 DL50 /0,05 mL do isolado de L. ega e 10 3,7- 4,7 LD50 /0,05 mL do CVS/32, usando as vias: intramuscular (IM), intradermica (ID), intranasal (IN) e abrasão epidermica (AE).A presença do antígeno viral foi confirmada pela prova de imunofluorescência direta. As porcentagens de mortalidadeobservadas com o isolado de L. ega foram as seguintes em hamster: 3,5% IM, 10,71% IN; em camundongo: 50.0%IM, 30.0% IN. A forma furiosa da doença foi predominante. As porcentagens de mortalidade observadas com o vírusCVS/32 em hamster foram as seguintes: 12.5% IM, 62.5% ID, 12.5% IN; em camundongo 100.0% IM, 70.0% ID,10.0% IN. Com este vírus foi observada raiva paralitica. A via AE mostrou-se inadequada para induzir doença. Operíodo de incubação foi de 5–7 dias para o CVS/32 e 11-16 dias para o isolado de L. ega, entre tanto os períodosclínicos oscilaram entre 4–7 dias para ambos os vírus. Varias substituições foram achadas em domínios antigênicos daglicoproteína: AI (posição 231), AII (34–42 e 198-200), domínio de fusão dependente de baixo pH (102–179), domínioda transmembrana (440–461) e resíduo 242. Esses vírus mostraram comportamentos biológicos distintos o que poderiaestar ligado às substituições nos domínios antigênicos anteriormente descritos.

[Antigen profile of rabies virus isolated from different species of non-hematophagous bats in the region of Presidente Prudente, State of São Paulo]. / Perfil antigênico do vírus da raiva isolado de diferentes espécies de morcegos não hematófagos da Região de Presidente Prudente, Estado de São Paulo.

Using the monoclonal antibody technique, the Clinical and Molecular Virology Laboratory of the Institute of Biomedical Sciences of the University of São Paulo typed 18 rabies virus samples from non-hematophagous bats of several species from the region of Presidente Prudente, SP, Brazil. Among these samples, 15 (82.3%) were defined as variant 3 (compatible with samples isolated from Desmodus rotundus bats) and three (16.7%) as variant 4 (compatible with samples isolated from Tadarida brasiliensis bats).

Perfil antigênico do vírus da raiva isolado de diferentes espécies de morcegos não hematófagos da Região de Presidente Prudente, Estado de São Paulo / Antigen profile of rabies virus isolated from different species of non-hematophagous bats in the region of Presidente Prudente, State of São Paulo

O Laboratório de Virologia Clínica e Molecular do Instituto de Ciências Biomédicas da Universidade de São Paulo, utilizando-se da técnica de anticorpos monoclonais, tipificou 18 amostras de vírus rábico provenientes de morcegos não hematófagos de várias espécies provenientes da Região de Presidente Prudente, SP, Brasil. Destas amostras, 15 (82,3 por cento) foram definidas como variante 3 (compatível com amostras isoladas de morcegos Desmodus rotundus) e 3 (16,7 por cento) como variante 4 (compatível com amostras isoladas de morcegos Tadarida brasiliensis).

Using the monoclonal antibody technique, the Clinical and Molecular Virology Laboratory of the Institute of Biomedical Sciences of the University of São Paulo typed 18 rabies virus samples from non-hematophagous bats of several species from the region of Presidente Prudente, SP, Brazil. Among these samples, 15 (82.3 percent) were defined as variant 3 (compatible with samples isolated from Desmodus rotundus bats) and three (16.7 percent) as variant 4 (compatible with samples isolated from Tadarida brasiliensis bats).

Efficiency of Matricaria chamomilla CH12 and number of doses of rabies vaccine on the humoral immune response in cattle.

This study evaluated the effect of Matricaria chamomilla and vaccination frequency on cattle immunization against rabies. Four groups (n = 15 /group) were treated with or without Matricaria chamomilla CH12 and vaccinated with one or two doses of rabies vaccine (30 day interval). No effect of chamomile was found on cattle immunization against rabies; however, antibody titers were protective in cattle vaccinated twice, while 93.3% of cattle vaccinated only once had titers under 0.5 UI/ml after 60 days. In conclusion, the use of chamomile did not alter the humoral immune response in cattle, and two vaccine doses are suggested for achieving protective antibody titers.

Molecular and geographic analyses of vampire bat-transmitted cattle rabies in central Brazil.

BACKGROUND: Vampire bats are important rabies virus vectors, causing critical problems in both the livestock industry and public health sector in Latin America. In order to assess the epidemiological characteristics of vampire bat-transmitted rabies, the authors conducted phylogenetic and geographical analyses using sequence data of a large number of cattle rabies isolates collected from a wide geographical area in Brazil. METHODS: Partial nucleoprotein genes of rabies viruses isolated from 666 cattle and 18 vampire bats between 1987 and 2006 were sequenced and used for phylogenetic analysis. The genetic variants were plotted on topographical maps of Brazil. RESULTS: In this study, 593 samples consisting of 24 genetic variants were analyzed. Regional localization of variants was observed, with the distribution of several variants found to be delimited by mountain ranges which served as geographic boundaries. The geographical distributions of vampire-bat and cattle isolates that were classified as the identical phylogenetic group were found to overlap with high certainty. Most of the samples analyzed in this study were isolated from adjacent areas linked by rivers. CONCLUSION: This study revealed the existence of several dozen regional variants associated with vampire bats in Brazil, with the distribution patterns of these variants found to be affected by mountain ranges and rivers. These results suggest that epidemiological characteristics of vampire bat-related rabies appear to be associated with the topographical and geographical characteristics of areas where cattle are maintained, and the factors affecting vampire bat ecology.

Vírus da raiva em quirópteros naturalmente infectados no Estado de São Paulo, Brasil / Rabies virus in naturally infected bats in the State of São Paulo, Southeastern Brazil

OBJETIVO: Identificar as espécies de morcegos envolvidas na manutenção do ciclo da raiva, verificar a distribuição do vírus da raiva em tecidos e órgãos de morcegos e os períodos de mortalidade dos camundongos inoculados. MÉTODOS: A positividade para o vírus da raiva foi avaliada por imunofluorescência direta em morcegos de municípios do Estado de São Paulo, de abril de 2002 a novembro de 2003. A distribuição do vírus nos morcegos foi avaliada pela inoculação de camundongos e infecção de células N2A, com suspensões a 20 por cento preparadas a partir de fragmentos de diversos órgãos e tecidos, além de cérebro e glândula salivar. A mortalidade dos camundongos foi observada diariamente, após inoculação intracerebral. RESULTADOS: Dos 4.393 morcegos pesquisados, 1,9 por cento foram positivos para o vírus da raiva, pertencentes a dez gêneros, com predomínio de insetívoros. A média do período máximo de mortalidade dos camundongos pós-inoculação a partir de cérebros e glândulas salivares de morcegos hematófagos foi de 15,33±2,08 dias e 11,33±2,30 dias; insetívoros, 16,45±4,48 dias e 18,91±6,12 dias; e frugívoros, 12,60±2,13 dias e 15,67±4,82 dias, respectivamente. CONCLUSÕES: As espécies infectadas com o vírus da raiva foram: Artibeus lituratus, Artibeus sp., Myotis nigricans, Myotis sp., Eptesicus sp., Lasiurus ega, Lasiurus cinereus, Nyctinomops laticaudatus, Tadarida brasiliensis, Histiotus velatus, Molossus rufus, Eumops sp. e Desmodus rotundus. A pesquisa de vírus em diferentes tecidos e órgãos mostrou-se que os mais apropriados para o isolamento foram cérebro e glândulas salivares.

OBJECTIVE: To identify the species of bats involved in maintaining the rabies cycle; to investigate the distribution of the rabies virus in the tissues and organs of bats and the time taken for mortality among inoculated mice. METHODS: From April 2002 to November 2003, bats from municipalities in the State of São Paulo were screened for the presence of the rabies virus, by means of direct immunofluorescence. The virus distribution in the bats was evaluated by inoculating mice and N2A cells with 20 percent suspensions prepared from fragments of different organs and tissues, plus the brain and salivary glands. The time taken for mortality among the mice was monitored daily, following intracerebral inoculation. RESULTS: Out of the 4,395 bats received, 1.9 percent were found positive for the rabies virus. They belonged to ten genera, with predominance of insectivores. The maximum mean times taken for mortality among the mice following inoculation with brain and salivary gland material were 15.33±2.08 days and 11.33±2.30 days for vampire bats, 16.45±4.48 days and 18.91±6.12 days for insectivorous bats, and 12.60±2.13 days and 15.67±4.82 days for frugivorous bats, respectively. CONCLUSIONS: The species infected with the rabies virus were: Artibeus lituratus, Artibeus sp., Myotis nigricans, Myotis sp., Eptesicus sp., Lasiurus ega, Lasiurus cinereus, Nyctinomops laticaudatus, Tadarida brasiliensis, Histiotus velatus, Molossus rufus, Eumops sp. and Desmodus rotundus. Virus investigation in the different tissues and organs showed that the brain and salivary glands were the most suitable sites for virus isolation.

[Rabies virus in naturally infected bats in the State of São Paulo, Southeastern Brazil]. / Vírus da raiva em quirópteros naturalmente infectados no Estado de São Paulo, Brasil.

OBJECTIVE: To identify the species of bats involved in maintaining the rabies cycle; to investigate the distribution of the rabies virus in the tissues and organs of bats and the time taken for mortality among inoculated mice. METHODS: From April 2002 to November 2003, bats from municipalities in the State of São Paulo were screened for the presence of the rabies virus, by means of direct immunofluorescence. The virus distribution in the bats was evaluated by inoculating mice and N2A cells with 20% suspensions prepared from fragments of different organs and tissues, plus the brain and salivary glands. The time taken for mortality among the mice was monitored daily, following intracerebral inoculation. RESULTS: Out of the 4,395 bats received, 1.9% were found positive for the rabies virus. They belonged to ten genera, with predominance of insectivores. The maximum mean times taken for mortality among the mice following inoculation with brain and salivary gland material were 15.33+/-2.08 days and 11.33+/-2.30 days for vampire bats, 16.45+/-4.48 days and 18.91+/-6.12 days for insectivorous bats, and 12.60+/-2.13 days and 15.67+/-4.82 days for frugivorous bats, respectively. CONCLUSIONS: The species infected with the rabies virus were: Artibeus lituratus, Artibeus sp., Myotis nigricans, Myotis sp., Eptesicus sp., Lasiurus ega, Lasiurus cinereus, Nyctinomops laticaudatus, Tadarida brasiliensis, Histiotus velatus, Molossus rufus, Eumops sp. and Desmodus rotundus. Virus investigation in the different tissues and organs showed that the brain and salivary glands were the most suitable sites for virus isolation.

Bat rabies in the north-northwestern regions of the state of São Paulo, Brazil: 1997-2002.

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.

Bat rabies in the north-northwestern regions of the state of São Paulo, Brazil: 1997-2002

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 percent was rabies virus positive, ranging from 0.2 percent in 1997 to 1.6 percent 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 percent) of rabies virus was found in Artibeus lituratus. Eptesicus and Myotis were the most frequent positive species (24.5 percent) of the Vespertilionidae family. The species Molossus molossus and Molossus rufus showed 14.3 percent positive bats. There were no differences in the distribution of positive rabies between females (33; 48.5 percent) and males (35; 51.5 percent). 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.

OBJETIVO: Os relatos sobre a ocorrência de raiva em morcegos no Brasil são esporádicos e isolados. Assim, o objetivo do estudo foi descrever a detecção do vírus da raiva em morcegos do Estado de São Paulo. MÉTODOS: Foram analisados 7.393 morcegos provenientes de 235 municípios do norte e noroeste do Estado de São Paulo, no período de 1997 a 2002 e identificados por meio de características morfológicas e morfométricas. Para a detecção do antígeno viral foi utilizada a técnica de imunofluorescência direta e o isolamento do vírus foi realizado por inoculação em camundongos. RESULTADOS: Das amostras examinadas, 1,3 por cento foram positivas para raiva, com variação de 0,2 por cento em 1997 a 1,6 por cento em 2001. Foram encontrados 98 morcegos com o vírus, 87 deles em área urbana. O vírus da raiva foi detectado pela imunofluorescência direta em 77 do total de amostras positivas, enquanto 92 produziram doença em camundongos inoculados e o período de incubação variou entre 4-23 dias. Em 43 municípios foi encontrado pelo menos um morcego positivo. Entre as espécies analisadas o vírus da raiva foi detectado com maior freqüência (33,7 por cento) em Artibeus lituratus. Os vespertilionideos do gênero Eptesicus e Myotis totalizaram 24,5 por cento dos morcegos positivos e as espécies do gênero Molossus (Molossus molossus e Molossus rufus), 14,3 por cento. A distribuição do vírus da raiva foi semelhante entre fêmeas (33; 48,5 por cento) e machos (35; 51,5 por cento). CONCLUSÕES: Morcegos positivos para raiva foram encontrados em situações que colocam em risco tanto a população humana como animais de estimação, exigindo medidas voltadas para o manejo destas espécies e de educação da população.

Diagnóstico laboratorial da raiva na região oeste do Estado de São Paulo / Laboratory diagnosis of rabies in the west region of São Paulo State

O laboratório do Pólo da Alta Sorocabana, Presidente Prudente, SP e Instituto Biológico de São Paulo, SP, realizaram avaliacão do diagnóstico laboratorial da raiva no período de 1996 a 2003 na região oeste do Estado de São Paulo. Para tal, se fez uso dos testes de imunofluorescência direta e prova biológica (inoculacão em camundongos) em 4.950 amostras encaminhadas para análise envolvendo as espécies canina, felina, bovina, quiróptera (morcego) e outras (eqüina, caprina, suína e roedores). Detectou-se a presenca de 74 amostras positivas, sendo que destas, 58 (78,4 por cento) foram referentes a quirópteros não hematófagos e 16 (21,6 por cento) para bovinos. O presente estudo epidemiológico constatou que, apesar do alto índice de positividade nos quirópteros, não houve um surto de raiva nestas espécies na região de Presidente Prudente no período estudado, porque o aumento no índice de positividade foi decorrente do significativo aumento de amostras de quirópteros encaminhadas ao laboratório para pesquisa do vírus rábico.

[Laboratory diagnosis of rabies in the west region of São Paulo State]. / Diagnóstico laboratorial da raiva na região oeste do Estado de São Paulo.

The Pólo da Alta Sorocabana laboratory, Presidente Prudente, SP, Brazil, and the Biological Institute in São Paulo State, performed an evaluation of rabies diagnosis from 1996 to 2003 in the west region of São Paulo State. For the tests, the laboratories used direct immunofluorescence and mice inoculation in 4,950 samples, that were sent for analysis involving dogs, cats, cattle, chiroptera (bats) and other animals. According to the results, the laboratories found 74 positive samples; of which 58 (78.4%) were non-hematophagous bats and 16 (21.6%) related to cattle. The present epidemiological study verified that in spite of the high positive index in chiroptera compared to the other species, there was not an outbreak of rabies in the species in the region of Presidente Prudente, from 1996 to 2003 but a rise in the positive index due to a marked increase in the number of chiroptera samples sent to the laboratories for virus rabies research.