Interstitial nephritis of slaughtered pigs in the State of Mato Grosso, Brazil / Nefrite intersticial em suínos abatidos no Estado de Mato Grosso

ABSTRACT

This study evaluated histological lesions in kidney samples from pigs with nephritis in two slaughterhouses in the State of Mato Grosso, Brazil. Four hundred samples were subjected to histology, anti-porcine circovirus type 2 (PCV2) immunohistochemistry (IHC), anti-Leptospira sp. immunofluorescence (IF), and polymerase chain reaction (PCR) for PCV2, porcine parvovirus (PPV), and Torque teno virus type 1 and 2 (TTV1, TTV2) detection. Histological lesions were found in 81% of the samples, and mononuclear interstitial nephritis was the most frequent lesion (77.50%). A follicular pattern was observed in 40.97% of the interstitial nephritis lesions. PCV2, PPV, TTV1, and TTV2 were identified in the kidneys by PCR in 27.25%, 28.50%, 94%, and 87.5% of the samples, respectively. Leptospira sp. was not detected through IF. Infection by PCV2 (PCR) and the presence of histological lesions (P=0.008) and giant cells (P=0.0016) were significantly associated. An association was observed between the TTV2-TTV1 co-infection (P<0.0001) and the risk for pathogenesis. These findings indicated that PCV2, PPV, TTV1, and TTV2 were widely distributed among pigs in the local farms and that the presence of these agents should be considered in the differential diagnosis of kidneys with interstitial nephritis in pigs.

RESUMO

O propósito desse estudo foi avaliar as lesões histológicas observadas em rins condenados por nefrite pelo Serviço de Inspeção Federal, em dois frigoríficos de Mato Grosso, Brasil. Foram coletados 400 rins condenados por nefrite e submetidos aos exames de histologia, imuno-histoquímica (IHC) para Circovirus suíno Tipo 2 (PCV2), imunofluorescência direta (IF) para Leptospira sp. e reação em cadeia pela polimerase (PCR) para detecção de PCV2, Parvovirus suíno (PPV) e Torque teno vírus Tipo 1 e 2 (TTV1 e TTV2). Foram observadas lesões histológicas em 81% das amostras, sendo nefrite intersticial mononuclear a mais freqüente (77,50%). Das lesões de nefrite intersticial encontradas, 40,97% apresentaram padrão folicular. Através da PCR foi observada ampla distribuição dos agentes (PCV2, PPV, TTV1 e TTV2) nas propriedades e municípios, com ocorrência de 27,25%, 28,50%, 94% e 87,50%, respectivamente. Leptospira sp. não foi detectada através da IF. Houve associação significativa da infecção do PCV2 com presença de lesão histológica (P=0,008) e de células gigantes (P=0,0016). Também houve associação entre a co-infecção TTV2 e TTV1 (P<0,0001). Esses achados indicam que os vírus PCV2, PPV, TTV1 e TTV2 devem ser considerados no diagnóstico diferencial de rins com nefrite intersticial em suínos.