Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions / Raiva bovina: relação do curso clínico, da linhagem genética do vírus e carga viral com a intensidade de lesões histológicas

Our objective was the characterization and staging of histological lesions in different anatomical sites of the central nervous system (CNS) of rabid cattle. The severity of the lesions was compared with the clinical stages of the disease, the variants of viral isolates, and with the load of virus. Thirty-one spontaneously affected rabid cattle the state of Santa Catarina underwent clinical follow-up and were eventually necropsied. CNS tissues were sampled and submitted to direct fluorescent antibody technique (DFAT), immunohistochemistry (IHC), routine histopathology with hematoxylin and eosin stain (HE), reverse transcriptase polymerase chain reaction (RT-PCR), and polymerase chain reaction in quantitative reverse transcriptase in real time (qRT-PCR). Affected cattle were allotted in four groups according to their clinical stage when euthanized: G1, euthanized while standing; G2, euthanized when in sternal recumbence; G3, euthanized when in lateral recumbence; and G4, affected cattle with natural death. In order to evaluate the degree of severity of the lesions and the presence of Negri bodies (NBs), the brain was sectioned at 9 sites. Additionally, spinal cord and trigeminal ganglion sections were examined. The intensity of the lesions was graded as either absent, mild, moderate, or marked, and the presence or absence of the NBs was noted. Histological lesions were characterized by lymphocytic and monocytic meningoencephalitis with NBs in 28 cases. In all analyzed groups, intensities of histological lesions ranging from mild to severe were observed. Brain regions with the highest inflammatory lesion intensity were the medulla at the level of obex, followed by the colliculus and thalamus. NBs were observed in a higher percentage in the cerebellum, followed by medulla at the obex level, striatum complex, and frontal telencephalon. The duration of the clinical course of the disease did not influence the intensity of the inflammatory lesion, but it did influence the presence of NBs, with a higher percentage of these inclusions in cattle that died naturally than in euthanized cattle. All isolated rhabdovirus included in this study were genetically compatible with samples from hematophagous bats Desmodus rotundus. The evaluation by qRT-PCR did not demonstrate a correlation between lesion intensity and the amount of virus.(AU)

Nosso objetivo foi a caracterização e estadiamento de lesões histológicas em diferentes locais anatômicos do sistema nervoso central (SNC) de bovinos raivosos. A gravidade das lesões foi comparada com os estágios clínicos da doença, as variantes dos isolados virais e com a quantidade de vírus. Trinta e um bovinos do estado de Santa Catarina, afetados naturalmente por raiva, foram acompanhados clinicalmente e, ao final, necropsiados. Os tecidos do SNC foram amostrados e submetidos a imunofluorescência direta, imunohistoquímica, histopatologia de rotina, reação em cadeia da polimerase via transcriptase reversa (RT-PCR) e reação em cadeia da polimerase em transcriptase reversa quantitativa em tempo real (qRT-PCR). Os bovinos afetados foram distribuídos em quatro grupos, de acordo com sua fase clínica: G1, eutanasiados quando ainda se mantinham em pé; G2, eutanasiados quando em decúbito esternal; G3, eutanasiados quando em decúbito lateral; e G4, bovinos afetados com morte natural. Para avaliar o grau de gravidade das lesões e a presença de corpúsculos de Negri (CNs), o cérebro foi seccionado em 9 locais. Além disso, seções da medula espinhal e do gânglio trigêmeo foram examinadas. A intensidade das lesões foi graduada como ausente, leve, moderada ou acentuada, e a presença ou ausência dos CNs foi anotada. Lesões histológicas foram caracterizadas por meningoencefalite linfocítica e monocítica com CNs em 28 casos. Em todos os grupos analisados foram observadas intensidades de lesões histológicas variando de leve a grave. As regiões cerebrais com maior intensidade de lesão inflamatória foram o bulbo no nível do obex, seguido do colículo e tálamo. CNs foram mais prevalentes no cerebelo, seguido pelo bulbo ao nível do óbex, corpo estriado e telencéfalo frontal. A duração do curso clínico da raiva não influenciou a intensidade da lesão inflamatória, mas influenciou a presença de CNs, com maior porcentagem dessas inclusões em bovinos que morreram naturalmente do que em bovinos sacrificados. Todos os isolados rabdovírus obtidos neste estudo eram geneticamente compatíveis com amostras provenientes de morcegos hematófagos Desmodus rotundus.(AU)

Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions / Raiva bovina: relação do curso clínico, da linhagem genética do vírus e carga viral com a intensidade de lesões histológicas

Our objective was the characterization and staging of histological lesions in different anatomical sites of the central nervous system (CNS) of rabid cattle. The severity of the lesions was compared with the clinical stages of the disease, the variants of viral isolates, and with the load of virus. Thirty-one spontaneously affected rabid cattle the state of Santa Catarina underwent clinical follow-up and were eventually necropsied. CNS tissues were sampled and submitted to direct fluorescent antibody technique (DFAT), immunohistochemistry (IHC), routine histopathology with hematoxylin and eosin stain (HE), reverse transcriptase polymerase chain reaction (RT-PCR), and polymerase chain reaction in quantitative reverse transcriptase in real time (qRT-PCR). Affected cattle were allotted in four groups according to their clinical stage when euthanized: G1, euthanized while standing; G2, euthanized when in sternal recumbence; G3, euthanized when in lateral recumbence; and G4, affected cattle with natural death. In order to evaluate the degree of severity of the lesions and the presence of Negri bodies (NBs), the brain was sectioned at 9 sites. Additionally, spinal cord and trigeminal ganglion sections were examined. The intensity of the lesions was graded as either absent, mild, moderate, or marked, and the presence or absence of the NBs was noted. Histological lesions were characterized by lymphocytic and monocytic meningoencephalitis with NBs in 28 cases. In all analyzed groups, intensities of histological lesions ranging from mild to severe were observed. Brain regions with the highest inflammatory lesion intensity were the medulla at the level of obex, followed by the colliculus and thalamus. NBs were observed in a higher percentage in the cerebellum, followed by medulla at the obex level, striatum complex, and frontal telencephalon. The duration of the clinical course of the disease did not influence the intensity of the inflammatory lesion, but it did influence the presence of NBs, with a higher percentage of these inclusions in cattle that died naturally than in euthanized cattle. All isolated rhabdovirus included in this study were genetically compatible with samples from hematophagous bats Desmodus rotundus. The evaluation by qRT-PCR did not demonstrate a correlation between lesion intensity and the amount of virus.(AU)

Nosso objetivo foi a caracterização e estadiamento de lesões histológicas em diferentes locais anatômicos do sistema nervoso central (SNC) de bovinos raivosos. A gravidade das lesões foi comparada com os estágios clínicos da doença, as variantes dos isolados virais e com a quantidade de vírus. Trinta e um bovinos do estado de Santa Catarina, afetados naturalmente por raiva, foram acompanhados clinicalmente e, ao final, necropsiados. Os tecidos do SNC foram amostrados e submetidos a imunofluorescência direta, imunohistoquímica, histopatologia de rotina, reação em cadeia da polimerase via transcriptase reversa (RT-PCR) e reação em cadeia da polimerase em transcriptase reversa quantitativa em tempo real (qRT-PCR). Os bovinos afetados foram distribuídos em quatro grupos, de acordo com sua fase clínica: G1, eutanasiados quando ainda se mantinham em pé; G2, eutanasiados quando em decúbito esternal; G3, eutanasiados quando em decúbito lateral; e G4, bovinos afetados com morte natural. Para avaliar o grau de gravidade das lesões e a presença de corpúsculos de Negri (CNs), o cérebro foi seccionado em 9 locais. Além disso, seções da medula espinhal e do gânglio trigêmeo foram examinadas. A intensidade das lesões foi graduada como ausente, leve, moderada ou acentuada, e a presença ou ausência dos CNs foi anotada. Lesões histológicas foram caracterizadas por meningoencefalite linfocítica e monocítica com CNs em 28 casos. Em todos os grupos analisados foram observadas intensidades de lesões histológicas variando de leve a grave. As regiões cerebrais com maior intensidade de lesão inflamatória foram o bulbo no nível do obex, seguido do colículo e tálamo. CNs foram mais prevalentes no cerebelo, seguido pelo bulbo ao nível do óbex, corpo estriado e telencéfalo frontal. A duração do curso clínico da raiva não influenciou a intensidade da lesão inflamatória, mas influenciou a presença de CNs, com maior porcentagem dessas inclusões em bovinos que morreram naturalmente do que em bovinos sacrificados. Todos os isolados rabdovírus obtidos neste estudo eram geneticamente compatíveis com amostras provenientes de morcegos hematófagos Desmodus rotundus.(AU)

Kinetics of rabies antibodies as a strategy for canine active immunization

Rabies, a zoonosis found throughout the globe, is caused by a virus of the Lyssavirus genus. The disease is transmitted to humans through the inoculation of the virus present in the saliva of infected mammals. Since its prognosis is usually fatal for humans, nationwide public campaigns to vaccinate dogs and cats against rabies aim to break the epidemiological link between the virus and its reservoirs in Brazil. During 12 months we evaluated the active immunity of dogs first vaccinated (booster shot at 30 days after first vaccination) against rabies using the Fuenzalida-Palácios modified vaccine in the urban area of Botucatu city, São Pauto state, Brazil. Of the analyzed dogs, 54.7% maintained protective titers (≥0.5 IU/mL) for 360 days after the first vaccination whereas 51.5% during all the study period. The present results suggest a new vaccination schedule for dogs that have never been vaccinated. In addition to the first dose of vaccine, two others are recommended: the second at 30 days after the first and the third dose at 180 days after the first for the maintenance of protective titers during 12 months.(AU)

Histopathological and immunohistochemical aspects of rabies in foxes Cerdocyon thous / Aspectos histopatológicos e imuno-histoquímicos da raiva em raposas Cerdocyon thous

Background: Several wild canids are considered reservoirs of rabies virus in the Northeast of Brazil, two wild canids have been reported as reservoirs of rabies virus Cerdocyon thous (crab-eating fox) and Pseudalopex vetulus (hoary fox) (previously called Dusicyon vetulus). The diagnosis of rabies in foxes is usually performed through fluorescent antibody test (FAT) and mouse inoculation test (MIT). However, until the moment, there are no detailed histopathological and immunohistochemical (IHC) description studies in foxes affected by this disease studies. Therefore, the aim of this work was the characterization of pathological and IHC findings of foxes with rabies sent to the Laboratory of Animal Pathology (LPA) of the Federal University of Campina Grande (UFCG) in Patos, semiarid region of Paraiba, Brazil. Case: Two foxes were sent to the LPA, phenotypic species identification through analysis of morphological aspects was performed and posteriorly necropsied. Fragments of organs of the thoracic and abdominal cavities, salivary glands, eye and Gasser ganglia were collected in addition to the central nervous system (CNS) that was collected integer and fixed at 10% buffered formalin. Later, serial sections of the 16 fragments of the CNS were performed, measuring about 0.5 cm thick and cleaved. Fragments of cerebrum, cerebellum, brainstem, spinal cord and salivary glands were sent...(AU)

Histopathological and immunohistochemical aspects of rabies in foxes Cerdocyon thous / Aspectos histopatológicos e imuno-histoquímicos da raiva em raposas Cerdocyon thous

Background: Several wild canids are considered reservoirs of rabies virus in the Northeast of Brazil, two wild canids have been reported as reservoirs of rabies virus Cerdocyon thous (crab-eating fox) and Pseudalopex vetulus (hoary fox) (previously called Dusicyon vetulus). The diagnosis of rabies in foxes is usually performed through fluorescent antibody test (FAT) and mouse inoculation test (MIT). However, until the moment, there are no detailed histopathological and immunohistochemical (IHC) description studies in foxes affected by this disease studies. Therefore, the aim of this work was the characterization of pathological and IHC findings of foxes with rabies sent to the Laboratory of Animal Pathology (LPA) of the Federal University of Campina Grande (UFCG) in Patos, semiarid region of Paraiba, Brazil. Case: Two foxes were sent to the LPA, phenotypic species identification through analysis of morphological aspects was performed and posteriorly necropsied. Fragments of organs of the thoracic and abdominal cavities, salivary glands, eye and Gasser ganglia were collected in addition to the central nervous system (CNS) that was collected integer and fixed at 10% buffered formalin. Later, serial sections of the 16 fragments of the CNS were performed, measuring about 0.5 cm thick and cleaved. Fragments of cerebrum, cerebellum, brainstem, spinal cord and salivary glands were sent...

Kinetics of rabies antibodies as a strategy for canine active immunization

Rabies, a zoonosis found throughout the globe, is caused by a virus of the Lyssavirus genus. The disease is transmitted to humans through the inoculation of the virus present in the saliva of infected mammals. Since its prognosis is usually fatal for humans, nationwide public campaigns to vaccinate dogs and cats against rabies aim to break the epidemiological link between the virus and its reservoirs in Brazil. During 12 months we evaluated the active immunity of dogs first vaccinated (booster shot at 30 days after first vaccination) against rabies using the Fuenzalida-Palácios modified vaccine in the urban area of Botucatu city, São Pauto state, Brazil. Of the analyzed dogs, 54.7% maintained protective titers (≥0.5 IU/mL) for 360 days after the first vaccination whereas 51.5% during all the study period. The present results suggest a new vaccination schedule for dogs that have never been vaccinated. In addition to the first dose of vaccine, two others are recommended: the second at 30 days after the first and the third dose at 180 days after the first for the maintenance of protective titers during 12 months.

Molecular epidemiology of rabies virus isolated of herbivores from Brazilian Amazon / Epidemiologia molecular de vírus da raiva isolados de herbívoros procedentes da Amazônia brasileira

Rabies virus samples (n = 17) A1 to A3 exhibit a similar composition and geographic distribution. Diverse composition of remaining groups of N and G gene is attributable to different sequences used in the alignments for each genomic region. Glycoprotein amino acid sequence showed molecular markers in sub-lineages A2, A3, A4 and A7. This information provides a better comprehension of molecular epidemiology of rabies, starting with the knowledge of viral lineages circulating in the Brazilian Amazon.(AU)

Amostras do vírus da raiva (n = 17) isoladas de bovinos (n = 11), equinos (n = 4) e bubalinos (n = 2) procedentes do Pará (n = 7), Tocantins (n = 6) e Rondônia (n = 4) foram submetidas à técnica de RT-PCR para amplificação parcial dos genes da Nucleoproteína (N) e Glicoproteína (G). As sequências nucleotídicas obtidas foram analisadas pelo método de reconstrução filogenética Neighbor-Joining com o modelo evolutivo Kimura 2-parâmetros. Todas as 17 amostras pertenceram ao cluster A, que se encontrou na linhagem associado com morcego hematófago Desmodus rotundus. A análise filogenética baseada nos genes N e G, sugere a presença de cinco sublinhagens (A1-A5) e sete sublinhagens (A1-A7), respectivamente. Quando se compara ambas as filogenias, as sublinhagens A1 até A3 mostram composição e distribuição geográfica concordante, já a diversidade observada na composição das sublinhagens restantes é atribuída ao uso de sequências de diferentes alinhamentos. A glicoproteína mostrou marcadores moleculares nas sublinhagens A2, A3, A4 e A7, o que fornece elementos para melhor compreensão da epidemiologia molecular da raiva das linhagens circulantes na Amazônia Brasileira.(AU)

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.(AU)

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.

Bovine rabies incidence in the state of Minas Gerais/Brazil, Between 2002 and 2006 / Incidência da raiva bovina no estado de Minas Gerais, Brasil, entre 2002 e 2006

Rabies is an infectious contagious disease of mammals present in all continents except Oceania. It is caused by a Lyssavirus and characterized by acute fatal encephalitis. It is considered endemic in Brazil and transmission to herbivores occurs mainly via vampire bats. The purpose of this study was to evaluate the incidence of bovine rabies in the state of Minas Gerais, as well as the diagnostic methods, applying the time series to analyze trend and seasonality in order to adjust a model to disease in cattle. Between 2002 and 2006, nervous tissue samples were obtained from deceased bovines presenting neurological symptoms and clinically suspected of rabies. The direct fluorescent antibody test (FAT) detected 40.38% (1,293/3,202) positive samples. From all FAT negative tissue samples, 2.67% (51/1,909) tested positive in a mouse inoculation test (MIT). No seasonality was observed and positive cases had a decrease of 0.14 per month.

A raiva é uma doença infecto-contagiosa dos mamíferos presente em todos os continentes com exceção da Oceania. É causada por um Lyssavirus e caracterizada como uma encefalite aguda fatal, sendo considerada endêmica no Brasil e a transmissão aos herbívoros ocorre principalmente através de morcegos hematófagos. O objetivo deste experimento foi avaliar a incidência de raiva bovina no Estado de Minas Gerais, assim como métodos de diagnóstico, empregando séries temporais para analisar a tendência e sazonalidade, podendo assim ajustar um modelo da doença em bovinos. Entre 2002 e 2006, amostras de tecido nervoso foram obtidas de bovinos que vieram a óbito com sintomas nervosos e com suspeita clínica de raiva. A imunofluorescência direta (IFD) detectou 40,38% (1.293/3.202) de amostras positivas. Das amostras de tecido consideradas negativas na IFD, 2,67% (51/1.909) foram consideradas positivas utilizando o teste de inoculação em camundongos (IC). Não foi observada sazonalidade e houve uma queda de 0,14 casos positivos ao mês.

Bovine rabies incidence in the state of Minas Gerais/Brazil, Between 2002 and 2006 / Incidência da raiva bovina no estado de Minas Gerais, Brasil, entre 2002 e 2006

Rabies is an infectious contagious disease of mammals present in all continents except Oceania. It is caused by a Lyssavirus and characterized by acute fatal encephalitis. It is considered endemic in Brazil and transmission to herbivores occurs mainly via vampire bats. The purpose of this study was to evaluate the incidence of bovine rabies in the state of Minas Gerais, as well as the diagnostic methods, applying the time series to analyze trend and seasonality in order to adjust a model to disease in cattle. Between 2002 and 2006, nervous tissue samples were obtained from deceased bovines presenting neurological symptoms and clinically suspected of rabies. The direct fluorescent antibody test (FAT) detected 40.38% (1,293/3,202) positive samples. From all FAT negative tissue samples, 2.67% (51/1,909) tested positive in a mouse inoculation test (MIT). No seasonality was observed and positive cases had a decrease of 0.14 per month.(AU)

A raiva é uma doença infecto-contagiosa dos mamíferos presente em todos os continentes com exceção da Oceania. É causada por um Lyssavirus e caracterizada como uma encefalite aguda fatal, sendo considerada endêmica no Brasil e a transmissão aos herbívoros ocorre principalmente através de morcegos hematófagos. O objetivo deste experimento foi avaliar a incidência de raiva bovina no Estado de Minas Gerais, assim como métodos de diagnóstico, empregando séries temporais para analisar a tendência e sazonalidade, podendo assim ajustar um modelo da doença em bovinos. Entre 2002 e 2006, amostras de tecido nervoso foram obtidas de bovinos que vieram a óbito com sintomas nervosos e com suspeita clínica de raiva. A imunofluorescência direta (IFD) detectou 40,38% (1.293/3.202) de amostras positivas. Das amostras de tecido consideradas negativas na IFD, 2,67% (51/1.909) foram consideradas positivas utilizando o teste de inoculação em camundongos (IC). Não foi observada sazonalidade e houve uma queda de 0,14 casos positivos ao mês.(AU)

Molecular epidemiology of animal rabies in the semiarid region of Paraíba, Northeastern Brazil / Epidemiologia molecular da raiva animal no semiárido da Paraíba, Nordeste do Brasil

In the semiarid of the state of Paraíba, the anti-rabies vaccination is not common, most of the local inhabitants who deal with the animals do not know the incidence of the disease in the region. In this study, samples of foxes (Pseudalopex vetulus), insectivorous bats (Molossus molossus), raccoons (Procyon cancrivorous) and domestic animals brains were submitted to the diagnosis of rabies, by using the direct fluorescent antibody technique (d-FAT) and mouse inoculation test (MIT). Of the 581 examined materials, 50 (8.60 %) were positive for d-FAT and 47 (8.09 %) for MIT. From the positive samples for rabies, RNAs were extracted and transformed to cDNA, at the Laboratory of Rabies/Faculdade de Medicina Veterinária e Zootecnia/USP, SP. The phylogenetic characterization of the N gene was performed at the Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Universidade Nihon, Faculdade de Ciências Bioresource, Fujisawa, Kanagawa, Japão. Based on the results of genotyping and phylogenetic analyzes, it is concluded that the epidemiology of rabies is complex in the semiarid of Paraíba, with different viral variants being maintained in domestic dogs, foxes, insectivorous bats and vampire bats. All the isolates examined belong to the genotype I of the genus Lyssavirus and it is possible to state that in the region, foxes are important sylvatic reservoirs of the rabies virus. (AU)

No semiárido do Estado da Paraíba, a vacinação antirrábica não é comum, a maioria dos habitantes locais que lidam com os animais não conhece a incidência da doença na região. Neste estudo, amostras do cérebro de raposas (Pseudalopex vetulus), de morcegos insetívoros (Molossus molossus), de guaxinins (Procyon cancrivorous) e de animais domésticos foram submetidas ao diagnóstico da raiva, pela técnica de imunofluorescência direta (IFD) e inoculação intracerebral em camundongos (ICC). Dos 581 materiais examinados, 50 (8,60%) foram positivos para IFD e 47 (8,09%) para o ICC. Das amostras positivas para raiva, os RNAs foram extraídos e transformados em DNA, no Laboratório de Raiva/Faculdade de Medicina Veterinária e Zootecnia/USP, SP. A caracterização filogenética do gene N foi realizada no Centro de Investigação Veterinária, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Ciências Bioresource, Nihon University, Fujisawa, Kanagawa, Japão. Com base nos resultados das análises filogenéticas e genotipagem, conclui-se que a epidemiologia da raiva é complexa no semiárido da Paraíba, com diferentes variantes virais sendo mantidas em cães domésticos, raposas, morcegos insetívoros e morcegos hematófagos. Todos os isolados analisados pertencem ao genótipo I do gênero Lyssavirus, e é possível afirmar que, na região, as raposas são importantes reservatórios silvestres do vírus da raiva.(AU)

Molecular epidemiology of animal rabies in the semiarid region of Paraíba, Northeastern Brazil / Epidemiologia molecular da raiva animal no semiárido da Paraíba, Nordeste do Brasil

In the semiarid of the state of Paraíba, the anti-rabies vaccination is not common, most of the local inhabitants who deal with the animals do not know the incidence of the disease in the region. In this study, samples of foxes (Pseudalopex vetulus), insectivorous bats (Molossus molossus), raccoons (Procyon cancrivorous) and domestic animals brains were submitted to the diagnosis of rabies, by using the direct fluorescent antibody technique (d-FAT) and mouse inoculation test (MIT). Of the 581 examined materials, 50 (8.60 %) were positive for d-FAT and 47 (8.09 %) for MIT. From the positive samples for rabies, RNAs were extracted and transformed to cDNA, at the Laboratory of Rabies/Faculdade de Medicina Veterinária e Zootecnia/USP, SP. The phylogenetic characterization of the N gene was performed at the Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Universidade Nihon, Faculdade de Ciências Bioresource, Fujisawa, Kanagawa, Japão. Based on the results of genotyping and phylogenetic analyzes, it is concluded that the epidemiology of rabies is complex in the semiarid of Paraíba, with different viral variants being maintained in domestic dogs, foxes, insectivorous bats and vampire bats. All the isolates examined belong to the genotype I of the genus Lyssavirus and it is possible to state that in the region, foxes are important sylvatic reservoirs of the rabies virus.

No semiárido do Estado da Paraíba, a vacinação antirrábica não é comum, a maioria dos habitantes locais que lidam com os animais não conhece a incidência da doença na região. Neste estudo, amostras do cérebro de raposas (Pseudalopex vetulus), de morcegos insetívoros (Molossus molossus), de guaxinins (Procyon cancrivorous) e de animais domésticos foram submetidas ao diagnóstico da raiva, pela técnica de imunofluorescência direta (IFD) e inoculação intracerebral em camundongos (ICC). Dos 581 materiais examinados, 50 (8,60%) foram positivos para IFD e 47 (8,09%) para o ICC. Das amostras positivas para raiva, os RNAs foram extraídos e transformados em DNA, no Laboratório de Raiva/Faculdade de Medicina Veterinária e Zootecnia/USP, SP. A caracterização filogenética do gene N foi realizada no Centro de Investigação Veterinária, Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Ciências Bioresource, Nihon University, Fujisawa, Kanagawa, Japão. Com base nos resultados das análises filogenéticas e genotipagem, conclui-se que a epidemiologia da raiva é complexa no semiárido da Paraíba, com diferentes variantes virais sendo mantidas em cães domésticos, raposas, morcegos insetívoros e morcegos hematófagos. Todos os isolados analisados pertencem ao genótipo I do gênero Lyssavirus, e é possível afirmar que, na região, as raposas são importantes reservatórios silvestres do vírus da raiva.

Raiva em bovinos diagnosticados no Setor de Patologia Veterinária da UFRGS, Porto Alegre, RS, Brasil no período de 2002 a 2007 / Rabies in cattle diagnosed by the Laboratory of Veterinary Pathology of the UFRGS, Porto Alegre, RS, Brazil in the period from 2002 to 2007

Background: Rabies is a zoonotic disease caused by rabies virus, the genus Lyssavirus e family Rhabdoviridae. The commonest way of rabies transmission is by the bite of an infected mammal. Bites by rabid animals generally inoculate virus-laden saliva through the skin into muscle and subcutaneous tissues. Rabies has previously been regarded as 100% lethal. In South America, rabies in cattle is transmitted by vampire bats Desmodus rotundus mainly resulting in a major economic problem and public health. The present study retrospectively analyzed data from cattle affected by rabies registered between 2002 and 2007, evaluating the epidemiological, clinical and pathological and immunohistochemistry studies. Materials, Methods & Results: This retrospective study included epidemiological, clinical, pathological, direct immunofluorescence, and immunohistochemistry findings from 26 cattle affected by rabies diagnosed by the Laboratory of Veterinary Pathology, UFRGS, Porto Alegre, RS, Brazil in the period from 2002 to 2007. The samples were selected from a histological diagnosis of lesions characteristic of rabies or positive direct immunofluorescence for rabies where samples were available for histological examination. The central nervous system (CNS) samples of cattle were reported in 10% formalin fixed, routinely processed for histology, embedded in paraffin, cut at 5 µm and stained with hematoxylin-eosin. Histological slides were also tested with immunohistochemistry procedure using a standardized protocol for rabies with a polyclonal primary antibody at a dilution of 1:1000 in phosphate buffered saline. Cattle between 3 months and 8 years of age were affected. Clinical course ranged from 1-10 days. Paralytical form was the most common. Clinical signs included motor incordination, paresis, and paralysis of the pelvic members and decubitus. The main histopathological findings were characterized by lymphoplasmacytic meningoencephalitis and nonsuppurative meningomyelitis associated with characteristic intracytoplasmic inclusion bodies in 88.4% (23/26) cases. In 92.3% (24/26), the animals examined were positive by immunohistochemistry for rabies. Positive labeling was present in perikarya of neurons as aggregates of granules or round formations associated with varying numbers of inclusion bodies, mainly observed in the Purkinje neurons of the cerebellum. Discussion: Rabies is an important disease of cattle in Brazil. In this study the diagnosis was based on the histopathological, direct immunofluorescence and positive immunostaining for rabies antigen. Immunohistochemistry is a laboratory technique that uses specific antibodies for visualization and evaluation as to the quantity, distribution and cellular localization of epitopes in histological sections, allowing the use of formalin-fixed tissues, which facilitates the transport of samples to the Laboratory, generating more time for sending. The average markup of 26 cases of cattle was 92.3%, but this average could be higher if other areas of the CNS had been used and the fixation time in formalin were lower. Immunohistochemistry is an important auxiliary tool for the diagnosis of rabies, especially in circunstances in which refrigeration cannot be adequately maintained, and in cases characterized by nonsuppurative meningoencephalitis with absence of inclusion bodies.

Rabies virus in a pregnant naturally infected southern yellow bat (Lasiurus ega)

Current knowledge on bat lyssavirus infections in their native hosts is limited and little is known about the virulence, virus dissemination and transmission among free-living insectivorous bats. The present study is a brief description of rabies virus (RABV) dissemination in tissues of a naturally infected pregnant southern yellow bat (Lasiurus ega) and its fetuses, obtained by reverse-transcriptase polymerase chain reaction (RT-PCR). The RT-PCR was positive in samples from the brain, salivary gland, tongue, lungs, heart, kidneys and liver. On the other hand, the placenta, three fetuses, spleen, intestine and brown fat tissue tested negative. This research demonstrated the absence of rabies virus in the fetuses, thus, in this specific case, the transplacentary transmission was not observed.(AU)

Levantamento e identificação dos aspectos epidemiológicos da raiva canina no município de Cuiabá MT / Survey and identification of the epidemiological aspects of canine rabies in the city of Cuiabá-MT

Reconhecida desde a antiguidade, a raiva é uma infecção aguda do sistema nervoso central que acomete mamíferos, sendo causada por um RNA vírus da família Rabidoviridae, gênero Lyssavírus. O Brasil, desde a implantação do programa de controle da raiva em áreas urbanas, vem apresentando um declínio de casos de raiva em cães e em seres humanos. Em Cuiabá, as atividades realizadas pelo Centro de Controle de Zoonoses voltadas para o controle da raiva como: vacinação antirrábica animal, bloqueios de foco, captura de animais errantes, entre outros, permitiu o bloqueio da circulação do vírus na espécie canina. Desde 2008, o município de Cuiabá não registra nenhum caso da doença na espécie canina. Com o objetivo de conhecer a distribuição temporal da raiva canina em Cuiabá- MT, assim como identificar os aspectos epidemiológicos dos cães infectados pelo vírus rábico e verificar as medidas de profilaxia para a raiva canina, adotadas pelo Centro de Controle de Zoonose do município de Cuiabá no período de janeiro de 2002 a dezembro de 2008, realizou-se o presente estudo. Para o estudo observacional descritivo foi empregado o banco de dados referente à série histórica do CCZ e do Laboratório de Apoio a Saúde Animal LASA ambos situados no município de Cuiabá- MT. O período de estudo foi de janeiro de 2002 a dezembro de 2008. Neste período foram examinadas 1021 amostras de cérebro de cães, destas 8,71% (89/1021) foram positivas e 91,29% (932/1021) negativas para a raiva. Os meses de maior incidência da doença foram os meses de janeiro 15,05% (14/93), fevereiro 12,5% (9/72), março 12,5% (9/72), abril 14,14% (9/72) e dezembro 13,69% (10/73). O maior número de cães doentes era macho 59,55% (53/89) com idade acima de dois anos 50,55% (45/89) e não domiciliados 67,41% (60/89). Em relação à imunoprofilaxia, a maioria dos cães 99,63% foi vacinada em campanhas. A cobertura vacinal ficou acima dos 80% exceto em 2006. Entre os animais que apresentaram a enfermidade o maior número, 67,41% (60/89), foi de cães não domiciliados, os chamados cães errantes. O percentual de cães domiciliados infectados pelos VR foi igual a 32,58% (29/89). As campanhas de vacinação, portanto, são fundamentais para a imunização do maior número de animais possível e a sociedade deve se conscientizar sobre a importância da raiva e as medidas que devem ser tomadas para controlá-la.(AU)

Known since the ancient times, the rabies is an acute infection of the central nervous system that affects mammals, caused by an RNA virus of the Rhabidoviridae family, Lyssavirus gender. Since the implantation of the urban area rabies control program in Brazil the number of cases in dogs and human have shown a decrease. In Cuiabá, the efforts to control the rabies, such as animal vaccination, focus isolation, capture of nomad animals and others realized by the Zoonosis Control Center has leaded to locking in the viral circulation in the canine species. Since 2008, zero cases of the disease in dogs were reported. In order to know the temporal distribution of canine rabies in Cuiabá MT and identify the epidemiologic aspects of the rabiess infected dogs, and verify the canine rabiess profilatic actions of the Zoonosis Control Center of the city of Cuiabá, during the period of January, 2002 to December , 2008, the present study was performed. The historic data base from Cuiabá - MT was obtained at the Zoonosis Control Center and at the Animal Health Support Laboratory and used to perform the descriptive and observational study. During the performance of the study, 1021 samples of canines brains were examined, 8,71% (89/1021) of them were positive and 91,29% (932/1021) of them were negative for the rabies test. The Months with higher incidence were January with 15,05% (14/93), February with 12,5% (9/72), March with 12,5% (9/72), April with 14,14% (9/72) and December with 13,69% (10/73). The major part of the infected dogs were males with 59,55% (53/89) older than two years old 50,55% (45/89) and were nomads animals 67,41% (60/89). 99,63% of the infected dogs were vaccinated in anti rabies vaccination campaigns. The vaccinal cover was higher than 80%, except in 2006. The percentual of the domiciled infected dogs by the rabies virus were 32,58% (29/89). Therefore the vaccination campaigns are essential for the immunization of a higher number of animals, and the society must be awareabout the importance of rabies and about the actions to control it.(AU)