Neospora caninum: evaluation of vertical transmission in slaughtered dairy cows (Bos taurus)

Abstract

Neospora caninum is a worldwide parasite recognized as one of the main parasites responsible for abortion in cattle. The objective of this study was to evaluate vertical transmission of N. caninum in dairy cows (Bos taurus) that were slaughtered at an abattoir in the state of Santa Catarina, southern Brazil. Blood samples (with and without EDTA) from 60 pregnant dairy cows and blood and tissue samples (brain, lung, heart and liver) from their fetuses were collected and used for PCR and serological evaluation. Blood samples from 60 non-pregnant cows were collected and used to detect antibodies. Anti-N. caninum antibodies were detected by indirect ELISA. Antibodies against N. caninum were observed in 41.6% (25/60) of the pregnant cows and in 43.3% (26/60) of the non-pregnant cows. Antibodies against the parasite were detected in sera from three fetuses (5.5%). PCR analysis revealed that 3.3% (2/60) of the cows and 6.6% (4/60) of the fetuses evaluated were positive for specific N. caninum primers. These positive fetuses were between 4-6 months of age. Therefore, considering PCR and serological tests to be indicative of vertical transmission in fetuses, 11.6% (7/60) of the fetuses were infected by N. caninum during gestation.Keywords: Neospora caninum, dairy cattle, vertical transmission, Bos taurus. ResumoNeospora caninum é um parasita de distribuição mundial reconhecido como um dentre os principais parasitas, responsável por abortamento em bovinos. O objetivo deste estudo foi avaliar a transmissão vertical de N. caninum em vacas leiteiras (Bos taurus) que foram submetidas ao abate em matadouro no Estado de Santa Catarina, sul do Brasil. Sangue (com e sem EDTA) de 60 vacas leiteiras prenhas e amostras de sangue e tecidos (cérebro, pulmão, coração e fígado) de seus fetos foram coletados e utilizados para PCR e avaliação sorológica. Amostras de sangue de 60 vacas não-gestantes foram obtidas e utilizadas para detecção de anticorpos. A detecção de anticorpos séricos anti-N. caninum foi avaliada pelo ELISA-teste indireto. Anticorpos anti-N. caninum foram observados em 41,6% (25/60) das vacas prenhas e em 43,3% (26/60) das vacas não-gestantes. Três fetos (5,5%) foram soros positivos para N. caninum. Análise pela PCR revelou que 3,3% (2/60) das vacas e 6,6% (4/60) dos fetos avaliados foram positivos para N. caninum. As idades dos fetos positivos eram de 4 a 6 meses. Portanto, considerando a PCR e a sorologia como indicativo de transmissão vertical em fetos, 11,6% (7/60) dos fetos foram infectados por N. caninum durante a gestação.

Occurrence of brucellosis, leptospirosis and neosporosis in cows with retained placenta in Southwest Paraná, Brazil

“…Langoni et al (2013) reported that the titration used is one of the important factors when estimating the prevalence of Neospora caninum, along with other factors such as race and test used. Macedo et al (2013) used ELISA diagnosis and found 15% of seropositive beef cattle, similar to the prevalence found in this study, showing that race and dairy ability were not relevant for the prevalence of this agent.…”

Ocorrência de anticorpos contra Neospora caninum em bovinos e cães oriundo de propriedades produtoras de leite do Norte Central do Estado do Paraná

“…PCR techniques are very useful in the diagnosis of Neospora because they allow to amplify very small amounts of DNA, even in tissues that are autolyzed and have a high sensitivity and specificity. Macedo et al (2013) have shown that the combination of diagnostic techniques such as PCR and serology improves the diagnosis of neosporosis.…”

“…Bovine neosporosis is a disease widely spread throughout the world and has been associated with cases of sporadic, endemic, and epidemic abortions in cattle (DUBEY et al, 2007;KAMGA-WALADJO et al, 2010). Studies have been conducted in several countries, including Brazil (CORBELLINI et al, 2002;ORLANDO et al, 2013;MACEDO et al, 2013), to identify Neospora caninum as the main cause of miscarriages in dairy cows LINDSAY, 1996;WILSON et al, 2016).…”

Diagnóstico diferencial das doenças neurológicas dos bovinos no estado do Paraná

“…Nos casos de Babesiose cerebral, as hemácias parasitadas foram detectadas em esfregaços sanguíneos e em decalques do telencéfalo corados (Barros et al 2006). O diagnóstico de neosporose foi confirmado por detecção do DNA do protozoário no tecido nervoso por PCR (Macedo et al 2013) e por histopatologia do SNC.…”