PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Silva M.L.C.R, Riet-Correa F., Galiza G.J.N., Azevedo S.S., Afonso J.A.B. & Gomes A.A.B. 2010. [Distribution of rabies vírus in the central nervous system in naturally infected ruminants.] Distribuição do vírus rábico em herbívoros naturalmente infectados. Pesquisa Veterinária Brasileira 30(11):940-944. Centro de Saúde e Tecnologia Rural, Universidade Federal de Campina Grande, Campus de Patos, Cx. Postal 64, Patos, PB 58700-000, Brazil. E-mail: luacristiny@yahoo.com.br With the aim to study the distribution of lesions the rabies virus in spontaneous cases of rabies in ruminants and to determine the efficiency of the direct fluorescent antibody test (DFA), mouse inoculation (MI) and presence of Negri bodies in the diagnosis of the disease, 48 cases of the rabies were examined. Samples of frontal, temporal, parietal and occipital cerebral cortex, hippocampus, thalamus, rostral and caudal colliculi, cerebellum, pons, medulla oblongata, basal nuclei and sections of the cervical, thoracic and lumbar spinal cord were examined. Of the 48 samples examined all were positive on DFA and MI, and in 30 (62.5%) Negri bodies were observed. However there were differences in the results of the three tests among different regions of the central nervous system. In the samples of the cerebral cortex in 38 cattle, the frequency of inclusion bodies was low (11-37%), and so was the positivity to DFA and MI (60-80%). In contrast, all samples of thalamus, pons and spinal cord were positive to DFA and MI. In other regions of the brain stem, positivity to these tests varied between 60% and 96.7%. On histologic examination, the major frequency of Negri bodies (88.2%) was observed in the cerebellum. In eight sheep the DFA and MI tests were positive in all sections of the CNS examined and Negri bodies were found in three sheep. Only two goats were examined; both were positive in DFA and MI tests and in one Negri bodies were found. These results suggest that the recommendations of the Brazilian Technical Manual for Rabies of Herbivores is adequate for rabies diagnosis, because their recommendations include the histologic study and the examination of cerebellum, and sections of the brainstem with high positivity to DFA and MI tests. However, a better recommendation is to send for DFA and MI half of the brain cut longitudinally and samples of the spinal cord, which will permit to examine one or two sections, and if those are negative to get back to the material and examine the rest of the sections. In contrast, to collect samples of the brain or half brain can be inappropriate for the diagnosis of other diseases of the CNS, for which the study of the whole fixed brain is necessary to recognize the symmetry or distribution of lesions. In these situations by the results obtained here, it can be recommended to send different sections of the spinal cord for DIF and MI tests and to fix the whole brain for gross and histologic examinations.

• Rabies raiva

Abstract in Portuguese:

RESUMO.- Silva M.L.C.R, Riet-Correa F., Galiza G.J.N., Azevedo S.S., Afonso J.A.B. & Gomes A.A.B. 2010. [Distribution of rabies vírus in the central nervous system in naturally infected ruminants.] Distribuição do vírus rábico em herbívoros naturalmente infectados. Pesquisa Veterinária Brasileira 30(11):940-944. Centro de Saúde e Tecnologia Rural, Universidade Federal de Campina Grande, Campus de Patos, Cx. Postal 64, Patos, PB 58700-000, Brazil. E-mail: luacristiny@yahoo.com.br Com o objetivo de identificar a distribuição das lesões do vírus rábico no sistema nervoso central de casos espontâneos de raiva em ruminantes e comparar as técnicas de imunofluorescência direta (IFD), inoculação em camundongos (ICC) e presença de corpúsculos de Negri para o diagnóstico da doença foram analisados materiais proveniente de 48 casos de raiva, incluindo amostras de córtex frontal, temporal, parietal e occipital, hipocampo, tálamo, colículo rostral e caudal, cerebelo, ponte, medula oblonga, núcleo da base e porções da medula cervical, torácica e lombar. De 48 amostras analisadas, todas foram positivas na IFD e na ICC e em 30 (62,5%) foram encontrados corpúsculo de Negri (CN). No entanto, houve diferenças importantes no resultados dos três testes nas diferentes regiões do SNC avaliadas. Nos cortes de córtex cerebral, em 38 bovinos, a presença de corpúsculos de inclusão foi baixa (11%-37%) assim como a positividade para IFD e ICC (60-80%). Pelo contrário, todas as amostras de ponte, tálamo e medula testados foram positivas para IFD e ICC. Em outras regiões do tronco encefálico e também no cerebelo a positividade para ICC e IFD foi de 60% a 96,7%. No cerebelo foi encontrada a maior frequência (88,2%) de corpúsculos de inclusão. Em oito ovinos as provas de ICC e IFD foram positivas em todos os cortes e foram observados corpúsculos de inclusão em três animais. Foram analisados somente dois casos de caprinos encontrando-se corpúsculos de inclusão em um e ambos foram positivos para IFD e ICC. Os resultados obtidos nesse trabalho sugerem que a conduta recomendada pelo Manual Técnico de Controle da Raiva dos Herbívoros (MTCRH) permite o diagnóstico de raiva associando o estudo histológico aos testes de IFD e ICC que incluem cerebelo, tálamo e tronco encefálico que apresentam alta positividade para as provas de IFD e ICC. No entanto, a melhor conduta é a de incluir metade do encéfalo cortado longitudinalmente e amostras de medula. Isto permite examinar por IFD e ICC uma ou mais regiões onde essas provas apresentam maior positividade e, posteriormente, se essas provas fossem negativas, retornar ao material original e examinar outras regiões. Por outro lado, a coleta de amostras dos locais recomendados pela MTCRH, assim com a coleta de metade do encéfalo, podem prejudicar o diagnóstico de outras doenças para o qual é necessário o estudo de todo o encéfalo após a fixação em formaldeído, para constatar a simetria e a distribuição das lesões. Nestes casos, com base nos resultados obtidos neste trabalho, pode ser recomendado para diagnóstico laboratorial de raiva o envio exclusivo de porções da medula cervical, dorsal e lombar, já que as três porções apresentaram 100% de positividade nas provas de IFD e ICC. Além disso, o estudo histológico de todas as porções do cérebro incluídas neste trabalho permitirá complementar o diagnóstico.

Abstract in English:

ABSTRACT.- Pignata W.A., Alves C.J., Azevedo S.S., Dantas A.F.M., Gomes A.A.B., Remígio F.R. & Lima F.S. 2009. [Prevalence for Caprine tuberculosis in paraibano semi-arid.] Prevalência para tuberculose caprina no semi-árido paraibano. Pesquisa Veterinária Brasileira 29(7):526-532. Centro de Saúde e Tecnologia Rural, Campus de Patos, Universidade Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: walvet8@hotmail.com Tuberculosis is an infectious disease of world wide distribution caused by pathogenic mycobacteria that affect humans and several mammals species. In order to determine the prevalence of tuberculosis in goats and to identify risk factors associated with infection, 1,866 goats of different breeds and ages from 84 herds in the microregion of Monteiro, State of Paraíba, Northeast Brazil, were tuberculinized by the Comparative Cervical Test (CCT). Interpretation of the CCT was checked by calculation of the difference obtained between skin measures correspondent to respective tuberculins, before and 72 hours after inoculation: negative, when bovine PPD is smaller than avian PPD or larger in up to 1.8mm; suspicious or inconclusive, reaction to bovine PPD larger than avian PPD between 1.9 and 2.4mm; positive, reaction to bovine PPD larger than or equal to avian PPD in 2.5mm. From goats submitted to CCT, 0.47% (9/1866) reacted positively (95% CI = 0.23%-0.94%). The prevalence of positive herds to caprine tuberculosis was 10.71% (95% CI = 5.02-19.37%). When submitted to necropsy and histopathologic examination, a positive goat at tuberculin test presented tuberculosis-like lesions. The presence of Acid-Alcohol Resistant Bacilli (BAAR) was also detected by direct bacterioscopy; in relation to herd size, herds with larger number of animals (>25) with high incidence of the disease, and presence of the infection was evidenced in properties that raised cattle in association with goats and did not carry out tuberculin tests in cattle.

• Caprine tuberculosis prevalence tuberculin test

Abstract in Portuguese:

ABSTRACT.- Pignata W.A., Alves C.J., Azevedo S.S., Dantas A.F.M., Gomes A.A.B., Remígio F.R. & Lima F.S. 2009. [Prevalence for Caprine tuberculosis in paraibano semi-arid.] Prevalência para tuberculose caprina no semi-árido paraibano. Pesquisa Veterinária Brasileira 29(7):526-532. Centro de Saúde e Tecnologia Rural, Campus de Patos, Universidade Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: walvet8@hotmail.com Tuberculosis is an infectious disease of world wide distribution caused by pathogenic mycobacteria that affect humans and several mammals species. In order to determine the prevalence of tuberculosis in goats and to identify risk factors associated with infection, 1,866 goats of different breeds and ages from 84 herds in the microregion of Monteiro, State of Paraíba, Northeast Brazil, were tuberculinized by the Comparative Cervical Test (CCT). Interpretation of the CCT was checked by calculation of the difference obtained between skin measures correspondent to respective tuberculins, before and 72 hours after inoculation: negative, when bovine PPD is smaller than avian PPD or larger in up to 1.8mm; suspicious or inconclusive, reaction to bovine PPD larger than avian PPD between 1.9 and 2.4mm; positive, reaction to bovine PPD larger than or equal to avian PPD in 2.5mm. From goats submitted to CCT, 0.47% (9/1866) reacted positively (95% CI = 0.23%-0.94%). The prevalence of positive herds to caprine tuberculosis was 10.71% (95% CI = 5.02-19.37%). When submitted to necropsy and histopathologic examination, a positive goat at tuberculin test presented tuberculosis-like lesions. The presence of Acid-Alcohol Resistant Bacilli (BAAR) was also detected by direct bacterioscopy; in relation to herd size, herds with larger number of animals (>25) with high incidence of the disease, and presence of the infection was evidenced in properties that raised cattle in association with goats and did not carry out tuberculin tests in cattle.

Abstract in English:

Lima E.F., Riet-Correa F., Castro R.S., Gomes A.A.B. & Lima F.S. 2005. [Clinical signs, distribution of the lesions in the central nervous system and epidemiology of rabies in northeastern Brazil.] Sinais clínicos, distribuição das lesões no sistema nervoso e epidemiologia da raiva em herbívoros na região Nordeste do Brasil. Pesquisa Veterinária Brasileira 25(4):250-264. Centro de Saúde e Tecnologia Rural, Campus de Patos, Universidade Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: riet@cstr.ufcg.br Twenty four outbreaks of rabies in cattle, 4 in horses, 2 in sheep, and 2 in goats are reported in northeastern Brazil. All outbreaks occurred in the state of Paraíba, except one in horses that occurred in the state of Rio Grande do Norte. All outbreaks, except one in sheep, were probably transmitted by vampire-bats, but the transmission by foxes (Dusicyon vetulus) is also possible. Clinical signs were characteristic for distribution of the lesions in the central nervous system (CNS). In cattle, signs were mainly of the paralytic form of rabies, caused by lesions on the spinal cord, brain stem and cerebellum; but some animals showed also depression, excitation and other signs due to cerebral lesions. In 3 out of 5 horses, the main clinical signs were due to lesions in the cerebrum, and 2 had the paralytic form. From 4 sheep and 2 goats affected, 4 showed clinical signs of the paralytic form; but in 1 goat and 1 sheep the main clinical signs were caused by cerebral lesions. All affected animals, except 1 goat, had a clinical manifestation period of 2-8 days. The only gross lesions were distention of the urinary bladder in 4 cattle and distention of the rectum in 2 others. Two horses had skin lesions due to traumatic injury. Histologic lesions were diffuse non-suppurative encephalomyelitis and meningitis. In the horses, and in one goat with a clinical manifestation period of 35 days, the lesions were more severe, with neuronal necrosis, neuronophagia, and presence of axonal spheroids. Negri bodies were found in 87% (20/23) of the cattle cases examined histologically. In small ruminants Negri bodies were found in 83% (5/6) of the cases. In sheep, goats and cattle, Negri bodies were more frequent in the cerebellum, but they were found also in brain stem, spinal cord and cerebrum. In horses, Negri bodies were found in small amounts only in the cortex of one animal, and in the cortex and hippocampus of another. Histologic lesions and Negri bodies in the trigeminal ganglia were less frequent than in the CNS. These results show that in rabies of herbivores, clinical signs and distribution of lesions in the CNS are variable, so that for the diagnosis and adequate clinical evaluation and the histologic study of different areas of the CNS are necessary. This also suggests that when the fluorescent antibody test and mouse inoculation test are negative, they should be repeated with samples from different areas of the brain and spinal cord. Frequency data of diseases from 4 diagnostic laboratories were used to estimate cattle deaths due to rabies in 3 Brazilian states. In Paraíba, with a population of 918,262 cattle, the annual death rate is estimated in 8,609 heads. In Mato Grosso do Sul, with a population of 23 millions cattle, deaths caused by rabies are estimated in 149,500 heads, and in Rio Grande do Sul, with a cattle population of 13 millions, cattle deaths due to rabies are estimated in 13,000 to 16,250 heads. If these data are used to estimate cattle losses in Brazil, with a cattle population of 195 millions, it can be estimated that 842,688 deaths are caused annually by rabies.

• Rabies cattle sheep goats horses pathology clinical signs economical impact.

Abstract in Portuguese:

Lima E.F., Riet-Correa F., Castro R.S., Gomes A.A.B. & Lima F.S. 2005. [Clinical signs, distribution of the lesions in the central nervous system and epidemiology of rabies in northeastern Brazil.] Sinais clínicos, distribuição das lesões no sistema nervoso e epidemiologia da raiva em herbívoros na região Nordeste do Brasil. Pesquisa Veterinária Brasileira 25(4):250-264. Centro de Saúde e Tecnologia Rural, Campus de Patos, Universidade Federal de Campina Grande, Patos, PB 58700-000, Brazil. E-mail: riet@cstr.ufcg.br Twenty four outbreaks of rabies in cattle, 4 in horses, 2 in sheep, and 2 in goats are reported in northeastern Brazil. All outbreaks occurred in the state of Paraíba, except one in horses that occurred in the state of Rio Grande do Norte. All outbreaks, except one in sheep, were probably transmitted by vampire-bats, but the transmission by foxes (Dusicyon vetulus) is also possible. Clinical signs were characteristic for distribution of the lesions in the central nervous system (CNS). In cattle, signs were mainly of the paralytic form of rabies, caused by lesions on the spinal cord, brain stem and cerebellum; but some animals showed also depression, excitation and other signs due to cerebral lesions. In 3 out of 5 horses, the main clinical signs were due to lesions in the cerebrum, and 2 had the paralytic form. From 4 sheep and 2 goats affected, 4 showed clinical signs of the paralytic form; but in 1 goat and 1 sheep the main clinical signs were caused by cerebral lesions. All affected animals, except 1 goat, had a clinical manifestation period of 2-8 days. The only gross lesions were distention of the urinary bladder in 4 cattle and distention of the rectum in 2 others. Two horses had skin lesions due to traumatic injury. Histologic lesions were diffuse non-suppurative encephalomyelitis and meningitis. In the horses, and in one goat with a clinical manifestation period of 35 days, the lesions were more severe, with neuronal necrosis, neuronophagia, and presence of axonal spheroids. Negri bodies were found in 87% (20/23) of the cattle cases examined histologically. In small ruminants Negri bodies were found in 83% (5/6) of the cases. In sheep, goats and cattle, Negri bodies were more frequent in the cerebellum, but they were found also in brain stem, spinal cord and cerebrum. In horses, Negri bodies were found in small amounts only in the cortex of one animal, and in the cortex and hippocampus of another. Histologic lesions and Negri bodies in the trigeminal ganglia were less frequent than in the CNS. These results show that in rabies of herbivores, clinical signs and distribution of lesions in the CNS are variable, so that for the diagnosis and adequate clinical evaluation and the histologic study of different areas of the CNS are necessary. This also suggests that when the fluorescent antibody test and mouse inoculation test are negative, they should be repeated with samples from different areas of the brain and spinal cord. Frequency data of diseases from 4 diagnostic laboratories were used to estimate cattle deaths due to rabies in 3 Brazilian states. In Paraíba, with a population of 918,262 cattle, the annual death rate is estimated in 8,609 heads. In Mato Grosso do Sul, with a population of 23 millions cattle, deaths caused by rabies are estimated in 149,500 heads, and in Rio Grande do Sul, with a cattle population of 13 millions, cattle deaths due to rabies are estimated in 13,000 to 16,250 heads. If these data are used to estimate cattle losses in Brazil, with a cattle population of 195 millions, it can be estimated that 842,688 deaths are caused annually by rabies.