Immunogenicity and cross reactivity indices of Streptococcus equi subsp. equi strains isolated from cases of Strangles and commercial vaccines / Imunogenicidade e índices de reatividade cruzada de cepas de Streptococcus equi subsp. equi isoladas de casos de Adenite Eqüina e vacinas comerciais

Horse Strangles appears frequently in animals vaccinated with commercial bacterins in Rio Grande do Sul, Brazil. Aiming to know the antigenic relationships of strains recovered from sick animals among them and with two vaccines profusely used in the state, bilateral cross reactivity indices (CRI) were estimated. In addition, the immunogenicity of vaccines prepared with field isolates and commercial vaccines was tested in mice. Antibody titers were measured by ELISA and expressed as seroconversions. Thirteen strains of Streptococcus equi subsp. equi, nine classified biochemically as typical and other four as atypical strains, were recovered from 35 sick horses belonging to 10 herds of Rio Grande do Sul, Brazil. The strains recovered from sick horses showed very close CRI, suggesting antigenic homogeneity among them, but not with the vaccinal strains. A vaccine produced with an atypical strain induced the highest seroconversion, 9.4, while two produced with typical strains were poorly-immunogenic. The commercial vaccines were less immunogenic than five and four vaccines produced with field strains, inducing seroconversions of 2.6 and 3.8, respectively.

A Adenite Eqüina é freqüente em animais vacinados com bacterinas comerciais no Rio Grande do Sul. Com o objetivo de determinar as relações antigênicas entre cepas isoladas de casos clínicos e duas vacinas amplamente utilizadas no Estado, foram determinados os índices de reatividade cruzada bilateral (IRC) entre elas. Também foi determinada a imunogenicidade em camundongos de vacinas preparadas com cepas de campo e de vacinas comerciais. Os títulos de anticorpos foram determinados por ELISA e expressos como soroconversão. Foram isoladas 13 cepas de Streptococcus equi subsp. equi de 35 casos clínicos de Adenite Eqüina em 10 diferentes rebanhos do Rio Grande do Sul, Brasil, das quais nove foram classificadas bioquimicamente como típicas e outras quatro como atípicas. As cepas de campo apresentaram elevada reatividade cruzada, sugerindo homogeneidade antigênica entre elas, mas não com as cepas vacinais. Uma vacina produzida com cepa atípica induziu soroconversão de 9.4, enquanto duas vacinas produzidas com cepas típicas foram pouco imunogênicas. As vacinas comerciais induziram soroconversões de 2.6 e 3.8, menores que quatro e cinco vacinas produzidas com cepas de campo, respectivamente.

Doenças do sistema nervoso central de equídeos no semi-árido / Diseases of the central nervous system in equidae in the Brazilian semiarid

As doenças do sistema nervoso central (SNC) de equídeos representam uma parcela importante das enfermidades diagnosticadas nestas espécies. O estudo destas e de outras enfermidades nas diferentes regiões do país é necessária para estabelecer formas eficientes de controle e profilaxia. O presente trabalho teve como objetivo descrever as características clínicas, epidemiológicas e patológicas das doenças do SNC de equídeos diagnosticadas no Laboratório de Patologia da Universidade Federal de Campina Grande, em Patos, Paraíba, que ocorreram entre janeiro de 2007 e dezembro de 2008. No período estudado, 159 casos ou surtos de doenças de equídeos foram diagnosticados. Destes, 49 (30,8 por cento) afetaram o SNC. A encefalopatia hepática na intoxicação por Crotalaria retusa foi a principal enfermidade com 14 casos (28,5 por cento), seguida por tétano com 13 (26,5 por cento) casos e raiva com 11 (22,,4 por cento) casos. Sete (14,2 por cento) casos foram de traumatismos afetando o SNC. Foram, também, diagnosticados 1 caso de leucoencefalomalacia, 1 de encefalite por herpesvírus eqüino-1, 1 de injeção acidental na artéria carótida, 1 surto de encefalomielite viral equina tipo leste, 1 surto de intoxicação por Turbina cordata e 1 surto de doença tremogênica de causa desconhecida. Cinco casos tiveram diagnóstico inconclusivo. Este trabalho comprova a importância do funcionamento de laboratórios de diagnóstico, nas diferentes regiões do país, para o conhecimento das doenças do rebanho e para a vigilância epidemiológica das mesmas.

Diseases of the central nervous system (CNS) in equidae are important in these species, and their knowledge in the different Brazilian regions is necessary to determine efficient control and preventive measures. This paper reports epidemiologic aspects, clinical signs and pathology of diseases of the CNS in equidae diagnosed by the Veterinary Pathology Laboratory at the Federal University of Campina Grande in the city of Patos, state of Paraíba, northeastern Brazil, during 2002-2008. During the period, 159 cases or outbreaks of those diseases were studied, 49 (30.8 percent) affecting the CNS. Hepatic encephalopathy caused by Crotalaria retusa poisoning, with 14 cases (28.5 percent), was the main disease observed. Tetanus was diagnosed in 13 (26.5 percent) cases and rabies in 11 (22.4 percent). In seven (14.2 percent) cases the death or euthanasia was due to traumatic lesions of the CNS. Also were diagnosed 1 case of leucoencephalomalacia, 1 case of encephalitis by equine herpesvirus-1, 1 case of intracarotid artery injection, 1 outbreak of Eastern equine encephalitis, 1 of Turbina cordata poisoning, and 1 of a tremogenic disease of unknown cause. In 5 cases the diagnosis was inconclusive. This paper indicates the importance of diagnostic veterinary laboratories, in the different Brazilian regions, for the knowledge of livestock diseases.

Trypanosoma evansi control and horse mortality in the Brazilian Pantanal

The impact of three treatment strategies for Trypanosoma evansi control on horse mortality in the Brazilian Pantanal based on four size categories of cattle ranches is explored. The region's 49,000 horses are indispensable to traditional extensive cattle ranching and T. evansi kills horses. About 13 percent of these horses would be lost, annually, due to T. evansi if no control were undertaken. One preventive and two curative treatment strategies are financially justifiable in the Pantanal. The best available technology for the treatment of T. evansi from a horse mortality perspective is the preventive strategy, which spares 6,462 horses, annually. The year-round cure spares 5,783 horses, and the seasonal cure saves 5,204 horses on a regional basis relative to no control strategy. Regardless of the strategy adopted, 39 percent of the costs or benefits fall to the largest ranches, while 18 percent fall to the smallest ranches

Single radial immunodiffusion potency test for standardization of indigenous equine influenza vaccine.

Single radial immunodiffusion (SRD) assays were used for measuring the haemagglutinin antigen contents of equine influenza vaccine prepared from an Indian virus isolate. A/Equine-2/Ludhiana/1/87 (H3N8). Five different preparations of the vaccine were standardized by SRD to prepare 913 doses, each containing 20 micrograms HA/ml-1 dose-1. This test also showed influenza virus subtype specificity as no cross reaction was observed between subtype 1 (H7N7) and subtype 2 (H3N8) viruses.