A Bayesian approach to estimate the accuracy of "in-house" ELISA assay to measure rabies antibodies from compulsory vaccinated dogs and cattle

Rabies is a vaccine-preventable disease that causes acute encephalitis in mammals, and it is still a significant public health problem in numerous countries. Infected dogs represent the main vectors involved in human rabies. Additionally, cattle rearing close to geographic areas where vampire bats are found presents an important connection with rural epidemiology. We applied two "in-house" enzyme-linked immunosorbent assay (ELISA) methodologies, considered alternatives to measure antibodies from vaccinated dogs and cattle, without employing the gold standard approach. The ELISA assays were performed on individual serum samples taken from domestic adult dogs and cows compulsory vaccinated against rabies (147 urban dogs and 64 cows; n = 211). The sandwich and liquid-phase competitive ELISA (scELISA and lpcELISA), considered "in-house" assays, were performed according to previous works. The only statistical methodology that allows this study is the Bayesian approach, developed to replace the conventional Hui-Walter paradigm. For conditional independent Bayesian model (one population, two tests and no gold standard) the prior information for sensitivity and specificity of each test, mode, prevalence and transformed (á, â) were submitted to Bayesian inference. The "in-house" lpcELISA revealed 16 - out of 261 serum samples - negative results, whereas in scELISA all results were positive. The Bayesian approach showed that prior information was specified for all parameters; posterior medians were Se scELISA 89%, Sp scELISA 88%, Sp lpcELISA 95% Se lpcELISA 98%, and prevalence (pi) of 99%, without the use of gold standard analysis to measure specific anti-rabies antibodies.

Serological survey for rabies in serum samples from vampire bats (Desmodus rotundus) in Botucatu region, SP, Brazil

The chiropterans constitute 25% of the world's mammal fauna. Due to the destruction of their natural ecosystem, the vampire bats have moved from nature to artificial roosts closer to man and domestic animals. This phenomenon has happened particularly in rural areas. Rabies is a viral anthropozoonosis, 100% lethal, and vampire bats (Desmodus rotundus) represent an important role in its epidemiology. D. rotundus were captured at night with mesh nets in partnership with the Botucatu Defense Office and sent to the Zoonosis Diagnostic Service, at the School of Veterinary Medicine and Animal Husbandry, UNESP. Serum samples from 204 bats were analyzed by enzyme-linked immunosorbent assay (ELISA) and fluorescent antibody viral neutralization test (FAVN) for rabies antibody detection. The results showed 7.4% of sera with titers higher or equal to 0.5 U for rabies antibodies, which demonstrated viral flow circulation among the studied region. Data suggest a need for constant monitoring accomplished by epidemiological and sanitary measures.

Serological survey for rabies in serum samples from vampire bats (Desmodus rotundus) in Botucatu region, SP, Brazil

The chiropterans constitute 25% of the world's mammal fauna. Due to the destruction of their natural ecosystem, the vampire bats have moved from nature to artificial roosts closer to man and domestic animals. This phenomenon has happened particularly in rural areas. Rabies is a viral anthropozoonosis, 100% lethal, and vampire bats (Desmodus rotundus) represent an important role in its epidemiology. D. rotundus were captured at night with mesh nets in partnership with the Botucatu Defense Office and sent to the Zoonosis Diagnostic Service, at the School of Veterinary Medicine and Animal Husbandry, UNESP. Serum samples from 204 bats were analyzed by enzyme-linked immunosorbent assay (ELISA) and fluorescent antibody viral neutralization test (FAVN) for rabies antibody detection. The results showed 7.4% of sera with titers higher or equal to 0.5 U for rabies antibodies, which demonstrated viral flow circulation among the studied region. Data suggest a need for constant monitoring accomplished by epidemiological and sanitary measures.(AU)

Effects of simvastatin in abdominal sepsis in rats / Efeitos da sinvastatina na sepse abdominal em ratos

PURPOSE: Statins are widely recognized as hypolipemic drugs, but some studies have observed anti-inflammatory and immunomodulatory effects, known as pleiotropic. The aims of this work was to study possible anti-inflammatory effects of simvastatin in abdominal sepsis. Serum pro-inflammatory cytokines and leukocytes count were determined in an experimental model of abdominal sepsis, using cecal ligation and puncture (CLP) in rats. METHODS: Twenty eigth Wistar rats weighing 285±12g were randomly divided in: CLP/Sinvastatin rats (n=7), treated with 10 mg/Kg of oral simvastatin 18 and 2 hs berofe CLP; CLP/Saline group rats (n=7), treated with oral saline; group Sham/Simvastatin (n=7), treated with simvastatin, and group Sham/Saline (n=7), treated with saline. Serum TNF-alpha, IL-1beta and IL-6 by ELISA and total leukocytes, neutrophils, lymphocytes, and eosinophils were determined 24 hs after CLP. ANOVA and Tukey test were used considering significant p<0.05. RESULTS: It was demonstrated that serum TNF-alpha, IL-1beta and IL-6 were respectively 364,8±42pg/mL; 46,3±18pg/mL and 28,4±13pg/mL in CLP/Sinvastatin rats, significantly lower (p<0.05) than in group CLP/Saline (778,5±86pg/ml; 176,9±46pg/ml; 133,6±21 pg/ml, respectively). The same results were observed in total leukocytes and neutrophils counts. CONCLUSION: These results clearly demonstrate that simvastatin is an effective agent that reduces cytokines levels and leukocyte count in sepsis, independently of its well-known lipid-lowering effects. Thus, HMG-CoA reductase inhibitors like simvastatin have important anti-inflammatory effects in abdominal sepsis in rats.(AU)

OBJETIVO: As estatinas são agentes reconhecidamente hipolipemiantes. Vários estudos têm revelado que eles têm ações pleiotrópicas, como antiinflamatória e imunomoduladora. Tentando-se entender o papel antiinflamatório da sinvastatina na sepse, foram analisados os níveis de citocinas pró-inflamatórias e contagem de leucócitos em modelo de sepse abdominal por ligadura e punção do ceco (LPC) em ratos. MÉTODOS: Foram utilizados 28 ratos Wistar pesando 285±12g, assim divididos: grupo sepse (n=14), submetidos a LPC e grupo sham (n=14), submetidos a laparotomia e manipulação suave do ceco. No grupo LPC/sinvastatina (n=7) os ratos receberam 10mg/kg de sinvastatina via oral 18 e 2 horas antes da LPC e no grupo LPC/salina (n=7) os ratos receberam injeção oral de solução salina 0,9 por cento. Os animais dos grupos sham/sinvastatina (n=7) e sham/salina (n=7) receberam o mesmo tratamento. Dosagem de TNF-alfa, IL-1beta e IL-6 por ELISA e contagem de leucócitos totais, neutrófilos, linfócitos e eosinófilos foram realizadas em todos os animais. Análise estatística foi feita pelo ANOVA e teste de Tukey, com significância p<0,05. RESULTADOS: Ficou demonstrado que as dosagens de TNF-alfa, IL-1beta e IL-6 atingiram valores de 364,8±42pg/ml; 46,3±18pg/ml e 28,4±13pg/ml no grupo submetido à sepse e tratados com sinvastatina, significantemente mais baixos do que no grupo sepse não tratados (778,5±86pg/ml; 176,9±46pg/ml; 133,6±21 pg/ml, respectivamente). O mesmo ocorreu na contagem de leucócitos totais e neutrófilos. CONCLUSÃO: A sinvastatina mostrou ação anti-inflamatória em ratos Wistar, diminuiu níveis de citocinas e leucócitos, sugerindo uso potencial na prevenção ou atenuação dos efeitos da sepse abdominal.(AU)

Comparação de métodos imunoenzimáticos para a detecção da resposta imune humoral em cães e bovinos vacinados e não vacinados contra o vírus da raiva

O vírus da raiva, pertencente à família Rhabdoviridade, é o causador da mais importante zoonose na Medicina Veterinária e a sua prevenção é realizada essencialmente por meio da vacinação e do respectivo monitoramento sorológico. As soroneutralização em camundongos e a inibição do foco de fluorescência em cultivo celular (FAVN). No presente trabalho, adaptamos as técnicas imunoenzimáticas (ELISA-E), sandwich (E-S) e competitivo de fase líquida (E-CFL), como mais uma alternativa ao monitoramento dos títulos de anticorpos vacinais em cães e bovinos. Em um total de 295 soros testados, entre cães e bovinos, apresentaram uma significativa correlação (E-CFL-FAVN r=0.893; E-S-FAVN r=0.773, respectivamente) quando os títulos foram comparados aos obtidos pela técnica de FAVN. A sensibilidade e especificidade relativas encaontradas para S-ELISA-FAVN foram de 94,7% e 93,7% em cães e 95,3% e 71,4% em bovinos. Para o E-CFL os valores para a mesma análise foram, 99,5% e 98%; 98,4% e 86,9%, respectivamente. Dessa forma, as técnicas aqui adaptadas, apresentaram vantagens, quando comparado ao teste padrão, conferindo exeqüibilidade na detecção de anticorpos anti-rábicos em cães e bovinos vacinados e não vacinados

The rabies virus belongs to Rhabdoviridae family causes one the most important zoonosis. The disease control has been done by vaccination of susceptible animals and the respective control of their population. The immune response has been controlled by vaccination and respective measure of antibobies using the mouse inoculation test and fluorescent antibody virus neutralization test (FAVN). The present study was done to develop and standard the ELISA methodologies, the sandwich ELISA (E-S) and liquid phase competition ELISA (LPC-E), to be applied on sera from cattle and dogs, vaccinated and non vaccinated. All the reagents were prepared according to standard procedures and the results were compared with those obtained from FAVN standard method. A total of 295 sera were analyzed and the correlation between S-E and FAVN obtained was r=0.773; and LPC-E and FAVN r=0.893. The sensitivity and specificity founded for S-E and FAVN was 94.7% and 93.7% and 95.3% and 71.4%, for dogs and cattle respectively. Regarding to LPC-ELISA, the values for the same analysis were 99.5% and 98%, 98.4% and 86.9%, respectively. Finnaly, the serological techniques applied here, S-ELISA and LPC-ELISA demonstrated good agreement with the standard FAVN to detect antibodies against rabies virus vaccination