Avaliação de um ELISA para detecção de anticorpos contra Babesia bigemina em bovinos e sua aplicação em um inquérito sorológico no Brasil

Abstract

An indirect enzyme-linked immunosorbent assay (ELISA) using a crude antigen was evaluated for its performance to detect Babesia bigemina antibodies. The sensitivity and specificity were 98.0% and 99.0%, respectively. In agreement with the high specificity, no cross-reactions were verified with sera from calves inoculated three times with 10 7 Babesia bovis organisms. With regard to the comparison of ELISA and indirect fluorescent antibody test (IFAT) in detecting antibodies against B. bigemina in calves experimentally infected with five Brazilian geographical isolates of this hemoparasite, IFAT was able to detect antibodies one day earlier in most of the calves' sera. There was a good agreement between results shown by ELISA and IFAT with sera from an enzootically stable area (k=0.61). However, there was no agreement between these serological tests with sera from an enzootically unstable area (k=0.33). The ELISA was employed in an epidemiological survey using with 1,367 sera from four counties in the Pantanal of Mato Grosso do Sul and characterized this region as an enzootically stable area, since the prevalences ranged from 87.7 to 98.9%. Therefore, this ELISA with high sensitivity, specificity and performance similar to IFAT can be employed in serological diagnosis of B. bigemina.

Soroprevalência de Babesia bovis em bovinos na mesorregião Norte Fluminense

“…Böse et al (1990) verificaram que ELISA e a prova mais indicada no diagnóstico sorológico, de rebanhos, para B. bovis, mesmo utilizando antígenos brutos. Esta técnica é ainda recomendada para uso em áreas estáveis como também em áreas instáveis enzooticamente (Madruga et al 1997).…”

Soroprevalência de Babesia bigemina em bovinos na mesorregião Norte Fluminense

“…No estado de Goiás o percentual de positividade observada foi de 97,5% (Linhares et al 1992), enquanto no estado de Pernambuco foi de 87,9% (Alves 1987), ambas determinadas pela IFI. Madruga et al (1997b) verificaram que, tanto em áreas de estabilidade quanto de instabilidade enzoótica, o ELISA indireto mostrou-se com especificidade e sensibilidade iguais ou superiores à IFI. No entanto, o ELISA é mais adequado para estudos soroepidemiológicos por garantir maior amplitude de titulação.…”

Epidemiological aspects of cattle tick fever in Brazil

“…In the Pantanal, the epidemiologic situation of tick fever varies because, throughout the year, the R. microplus presence is irregular. While the bordering area of the Cerrado and Pantanal biomes was classified as stable to babesiosis because of the seroprevalence of 83.9% (1145/1365) found for B. bovis (Madruga et al, 2000) and of 94.3% (1289/1367) for B. bigemina (Madruga et al, 2001), the Pantanais mesoregion in the State of Mato Grosso do Sul was classified as unstable, with seroprevalences of 72.25% (289/400), 61.25% (245/400) and 51.25% (205/400) for A. marginale, B. bovis and B. bigemina, respectively (Ramos et al, 2020). In the Pantanal, tick fever occurs in some farms with low and high areas when cattle are transported from the former to the latter.…”