Enzootic bovine leukosis: performance of an indirect ELISA applied in serological diagnosis

Abstract

ABSTRACT:Bovine Leukosis Virus (EBLV) is a widely distributed pathogen agent in the bovine population of many countries, especially in dairy cattle. Once the bovine is infected, it remains as a virus carrier for life and such state is correlated with a specific antibody detectable level. In this study the evaluation of an indirect ELISA (Leucokit-La Plata) to detect antibodies against EBLV is presented. Comparing it with the Immunodiffusion as gold standard test, the sensitivity is 98.93%, the specificity 79.74%, the negative predictive value 99.56% and the positive predictive value 61.26%. The correspondence between both tests is 83.9% which is similar to the result mentioned by other authors (82.2%). The concordance was evaluated by calculating Kappa and Youden's J coefficients, obtaining values classified as good for both coefficients. Comparing Leucokit-La Plata and another commercial reference kit (Chekit Leucotest Bommeli AG, Bern Switzerland), the sensitivity (97.05%), specificity (94.11%), negative predictive value (92.30%) and positive predictive value (97.77%), were obtained. Applying Kappa and Jouden's Index (J) coefficients an almost perfect concordance was obtained between both kits. The Leucokit-La Plata is appropriate to apply to the commercialization of live bovines to export, bovine selection for hemo-vaccines and the implementation of control and eradication programmes.

Establishment of a novel diagnostic test for Bovine leukaemia virus infection using direct filter PCR

“…This study is the first in which blood-spotted filter paper was used as the template for PCR to detect the BLV proviral genome directly, without DNA extraction. The direct filter PCR method showed 90.1% sensitivity, 97.5% specificity, and a kappa value 0.88 when compared with the BLV-ELISA method and a kappa (González, Licursi, & Bonzo, 2007).…”

“…BLV persistently infects cattle, and the specific antibody against BLV is detected for lifelong. Once cattle are infected with BLV, it remains as a virus carrier for life and such state is correlated with a specific antibody detectable level (González, Licursi, & Bonzo, ). Indeed, we have confirmed the BLV‐specific antibody was detected for over one year in BLV‐infected cattle in our study conducted from March 2018 to July 2019 using periodic tests.…”

Inquérito soroepidemiológico de leucose enzoótica bovina nos bovinos de corte e de leite no município de Catalão, Goiás e correlação com os fatores predisponentes

“…A infecção é transmitida principalmente por via horizontal, de forma iatrogênica, através da passagem de linfócitos infectados, monta natural, por fômites contaminados e, em menor escala, por vetores. Na via vertical, tanto o leite quanto o sangue podem ser fontes de contaminação, sendo responsável por até 5% de nascidos positivos ou de indivíduos reservatórios da enfermidade (GONZÁLEZ et al, 2007;BARROS, 2007).…”

“…Uma vez infectado, o animal permanece como carreador do vírus por toda a vida, podendo-se assim detectar os níveis de anticorpos. O índice de mortalidade nos animais infectados pode chegar a 15% (BARROS, 2007;GONZÁLEZ et al, 2007;SILVA et al, 2008).…”