ELISA test for the diagnosis of cysticercosis in pigs using antigens of Taenia solium and Taenia crassiceps cysticerci

Abstract

SUMMARYIn the present study ELISA was standardized for the diagnosis of swine cysticercosis based on necropsy parameters and confirmed positive and negative control sera. Serum samples from pigs with other infections were also assayed to determine possible crossreactions. Four antigens were assayed: from Taenia crassiceps vesicular fluid (VF-Tcra) and crude larvae extract (T-Tcra), and from Taenia solium extracts of scolex (S-Ts) and of larvae (T-Ts). A checkerboard evaluation of antigen, serum and conjugate dilutions, as well as the use of Tween-20 and skim cow milk in wash and blocking solution had a marked effect on improving ELISA performance. All the antigens showed a good performance, but VF-Tcra was the best, with 96.0% and 80.0% sensitivities for cut-offs respectively at 2sd and 3sd, and corresponding specificities of 97.5% and 100.0%. Cross-reactivity was observed only with hydatidosis and ascaridiosis. In view of the high performance observed, the ELISA test should be recommended for the diagnosis of cysticercosis in suspected swine in slaughterhouses and for the screening of cysticercosis in swine production. These results will support integrated measures of cysticercosis control throughout the chain of swine production, effectively contributing to public health.

Cysticercosis in experimentally and naturally infected pigs: parasitological and immunological diagnosis

“…The ELISA test was performed as described by Pinto et al (2000), with some modiϐications. The optimal dilutions of antigens, test serum samples and conjugate were determined through checkerboard titration.…”

“…These results corroborate those described by Boa et al (2002), who found that only 10.6% of metacestodes are present in muscles or organs indicated for the search of cysticercosis. As detailed necropsy of pig carcasses followed by the enumeration of cysticerci (considered here as the golden standard) is time-consuming and expensive, it is therefore impractical for traditional inspection and would lead to commercial losses (Gonzalez et al 1990, Pinto et al 2000.…”

“…Serological diagnosis methods are important tools for epidemiological studies, as they can be applied to living animals and on a large scale (Gonzales et al 1990) and can help detect cysticercosis in animals with light or recent infections (Pinto et al 2000).…”

Desempenho do ELISA no diagnóstico da cisticercose utilizando bovinos experimentalmente e naturalmente infectados com o metacestódeo de Taenia saginata

“…Ao utilizar os mesmos critérios para seleção do ponto de corte 1 e 2, contudo adicionando 3 SD, pôde-se observar que do total de amostras somente 4 apresentaram-se como positivas para o ponto de corte 1 (sensibilidade de 1,99%), e para o ponto de corte 2, foi possível confirmar 29 amostras positivas (sensibilidade 14,4%). De acordo com Pinto et al (2000) quando o ponto de corte é aumentado para 3SD é previsível a queda da sensibilidade do teste.…”

“…Vale ressaltar que a utilização de 2 ou 3 SD como critério de ponto de corte é dependente do objetivo dos ensaios, visto que, a utilização de 3 SD é mais apropriado para fins de diagnóstico e 2 SD para testes de triagem ou seleção (PINTO et al, 2000). Paulan et al (2013) relatam também a correlação entre ponto de corte e taxa de sensibilidade do ELISA.…”