Occurrence of abortions induced by Neospora caninum in dairy cattle from Santa Catarina, southern Brazil

Abstract

The aim of the present study was to investigate the occurrence of N. caninum associated with abortions of dairy cattle from Santa Catarina state, southern Brazil by using enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC), and polymerase chain reaction (PCR). Blood from dairy cows that aborted along with intrathoracic fluid and tissue samples (brain, heart, liver, and lung) from their fetuses were collected and used for serology; PCR, histopathological, and immunohistochemistry (IHC) evaluations were also conducted. Twenty-one cows (51.2%) out of 41, and eight fetuses (26.7%) out of 30 were ELISA (HerdCheck, IDEXX) positive for N. caninum. Dams > 36 months of age had a higher risk of being serum positive than younger animals. PCR and IHC revealed that 38.8% (14/36) and 25.0% (9/36) of the fetuses were positive for N. caninum, respectively for each of the tests. Seropositive cows had a higher frequency of fetuses that were also positive by either intrathoracic fluid, PCR, or IHC. In summary, the present study observed a high frequency of N. caninum in abortions from dairy cows from southern Brazil, with a higher N. caninum prevalence found in cows that were older than 36 months. In addition, serology, PCR, and IHC should be used all together for better diagnosis of neosporosis in cattle.Keywords: Neosporosis, fetuses, lesion, serology, cattle. ResumoO objetivo deste estudo foi avaliar a ocorrência de N. caninum associado a abortamentos em vacas de leite do estado de Santa Catarina, sul do Brasil pelo uso das técnicas de ELISA (HerdCheck, IDEXX), reação em cadeia pela polimerase (PCR) e imunohistoquímica (IHC). O sangue das vacas leiteiras que abortaram, bem como, o líquido intratorácico e amostras de tecidos (cérebro, coração, fígado e pulmão) de seus fetos foram coletados e usados para sorologia, PCR (Np21+ e Np6+), e IHC. Vinte e uma vacas (51,2%) de um total de 41, bem como, oito fetos (26,7%) de um total de 30 foram positivos no ELISA (IDEXX) para N. caninum. As vacas > 36 meses de idade tiveram um maior risco de serem soropositivas do que os animais mais jovens. PCR e IHC revelaram que 38,8% e 25,0% dos fetos foram positivos para N. caninum, respectivamente para cada um dos testes. As vacas soropositivas tiveram uma maior frequência de fetos que também foram positivos no fluído intratorácico, na PCR ou na IHC. Em resumo, o presente estudo observou uma alta frequência de N. caninum em abortos de vacas leiteiras na região estudada, com maior prevalência de N. caninum em vacas com mais de 36 meses de idade. Além disso, sorologia, PCR e IHC deveriam ser utilizadas conjuntamente para melhor diagnóstico de neosporose em bovinos.

Serology for Neosporosis, Q fever and Brucellosis to assess the cause of abortion in two dairy cattle herds in Ecuador

“…Hence, more research is necessary and we have planned to genotype the Neospora strains of our study area. We will also look to directly confirm the presence of N. caninum in abortion material or in the fetuses, as was achieved in a study in southern Brazil, where PCR revealed that 38.8% of the aborted fetuses were positive for N. caninum [24].…”

Canine morbillivirus (canine distemper virus) with concomitant canine adenovirus, canine parvovirus-2, and Neospora caninum in puppies: a retrospective immunohistochemical study

“…Finally, all slides were counter-stained with Harris haematoxylin and assembled with a commercial resin. Positive antigen controls consisted of FFPE tissue sections from previous studies 13 , 18 , 38 , 63 , 64 ; negative controls consisted of the diluents of the primary antibodies which substituted each primary antibody. Positive and negative controls were included in each assay.…”

Neospora caninum in properties in the west region of Paraná, Brazil: prevalence and risk factors

“…Orlando et al (2013), after analyzing tissues of 60 fetuses through PCR and IHC, found 23.33% of the samples to be positive for the protozoan. Meanwhile, analyzing the brain, lung, liver, heart and intrathoracic fluid of 30 fetuses of dairy cattle from the State of Santa Catarina, Macedo et al (2017) found 38.8% positives through the PCR technique, 25% through immunohistochemistry and 26.7% through of the ELISA.…”