Preliminary determination of median lethal dose of Azadirachta indica (A. ) Juss bark extract against Boophilus microplus

The study was carried out in order to determine the effective dose of Azadirachta indica as an acaride. From a range of effective doses, nine (9) test doses ranging from zero (0) parts per million to one hundred and fifty parts (150) per million were selected. The test species Boophilus microplus was subjected to a standard bioassay. A dose response curve was plotted of percentage mortality of B. microplus against logarithmic dosage of A indica. The lethal dose, LD50 and LD100 were also determined. The LD50 was 30.20 parts per million and LD100 was found to lie between 80 and 100 parts per million. Regression analysis was performed to verify correlation of data. The data proved to be linear with a correlation coefficient of 0.89. The results of this study indicate that when the dose required to achieve 50 percent mortality is compared to average yield of A. indica bark extract obtained in previous studies (Maharaj et al 2003), the extract appears to be feasible with respect to production for use as a prospective pesticide. This is an important point for consideration as the failure in the commercialization of many plant products is often due to the yields being too low. The bark extract of Azadirachta indica has thus far proven to be worthy of consideration for further development as a phytoacaricide

The value of in vitro cell culture of granulocytes in the detection of Ehrlichia

Peripheral blood leukocytes from different animals were isolated from whole blood and maintained in Dulbeco's medium containing homologous serum without antibiotics. After 72 hrs microscopic examination of these cells showed that most animals were infected with Ehrlichia. Observation of thin blood smears from the same animals showed that only two were positive for Ehrlichia. The results of this investigation show that leukocyte culture is superior to the traditional thin blood film method in the detection of Ehrlichia and that asymptomatic carriers are easily detected. The method is inexpensive and does not require specific cell lines although it is necessary to use sterile sera.

Leucócitos do sangue periférico de diferentes animais foram isolados do sangue total e mantidos em meio de Dulbeco, contendo soro homólogo sem antibióticos. Após 72 horas, um exame microscópico destas células mostrou que a maioria dos animais era infectada com Ehrlichia. Observação de esfregaços de sangue dos mesmos animais mostrou que apenas dois eram positivos para Ehrlichia. Os resultados desta pesquisa mostraram que a cultura de leucócitos é superior ao método tradicional de película de sangue na detecção de Ehrlichia , e que portadores assintomáticos são facilmente detectados. O método é de baixo custo e não exige linhas de células específicas, embora seja necessário o uso de soro estéril.

A longitudinal study on enteropathogenic infections of livestock in Trinidad

A longitudinal study was conducted on selected livestock farms to determine the prevalence of enteropathogens in diarrhoeic and non-diarrhoeic animals. The enteropathogens assayed from faecal samples and rectal swabs were bacteria (Escherichia coli, Campylobacter spp. Salmonella spp. and Yersinia enterocolitica), parasites (coccidia, gastrointestinal nematodes and Cryptosporidium spp.) and viruses (group A rotavirus and parvovirus). The prevalence of the enteropathogens in various animal species was related to age and month of the year. Generally, younger animals presented a higher prevalence of infection by enteropathogens than older animals while most infections occurred between the months of January and April.

Um estudo longitudinal foi realizado em fazendas de criação selecionadas, para determinar a prevalência de enteropatógenos em animais com ou sem diarréia. Os enteropatógenos analisados de amostras fecais e swabs retais foram: bactérias (Escherichia coli, Campylobacter spp, Salmonella spp e Yersinia enterocolitica); parasitas (coccídeos, nematóides gastrintestinais e Cryptosporidium spp ) e vírus (Rotavírus grupo A e parvovírus). A prevalência dos enteropatógenos em várias espécies de animais foi relacionada à idade e mês do ano. Geralmente, a prevalência de infecção por enteropatógenos foi maior entre os animais mais jovens que entre os animais mais velhos, enquanto a maioria das infecções ocorreu entre os meses de janeiro e abril.