BACKGROUND: Porcine circovirus diseases (PCVD) are still one of the commonest diseases of swine in Korea. The objective of the present paper is to report a case of pig co-infected with porcine circovirus type 2 and streptococcus suis.
CASE PRESENTATION: A 40 days old pig exhibited symptoms of diarrhea; a difficulty breathing and neurological sign was diagnosed for possible cause(s) of death by pathological and molecular based methods. The notable gross lesions were (i) rubbery consistency of the lungs with multiple petechial hemorrhages, (ii) congestion of lymp nodes, and brain; (iii) the wall of the small intestine was slight congestion, yellowish fluid accumulated in the lumen was observed. The main microscopic lesions were: (i) interstitial pneumonia, degeneration of lymphocyte, dense mononuclear cell infiltrated in the interstitium; (ii) germinal centers of lymph node were reduced or absent with depletion of mature lymphocytes and distribution of pyknotic nuclear material; (iii) lymphocytes, macrophages, and mainly plasma cells distributed along blood vessels within the meninges of the brain. By extensive examining previously known pathogens of nervous, respiratory, and digestive systems, only PCV2 and Streptococcus suis were systematically detected and confirmed by sequencing.
CONCLUSION: The pig described in this study suffered from an atypical porcine circovirus disease which was based on the presence of PCV2 systemically and a typical lesion of lymphoid depletion.
