Application of Oral Fluid Sample to Monitor Porcine circovirus-2 Infection in Pig Farms

구강액을 이용한 양돈장의 Porcine circovirus-2 감염에 대한 모니터링

  • Kim, Won-Il (College of Veterinary Medicine and Bio-safety Research Institute, Chonbuk National University)
  • 김원일 (전북대학교 수의과대학 생체안전성연구소)
  • Accepted : 2010.12.07
  • Published : 2010.12.31

Abstract

Porcine circovirus-2 (PCV2) has been implicated in many clinical diseases/syndromes that are now referred to as PCV-associated diseases (PCVAD). Due to significant economic losses caused by PCVAD, many swine operations have launched extensive monitoring programs for PCV2. Traditional serum sampling is, however, rather expensive and laborious, hampering effective large scale pathogen surveillance. A field-based longitudinal study was conducted to assess the utility of pen-based oral fluid sample as an alternative to serum for herd PCV2 testing. Six pens (25 pigs/pen) at each of 3 different sites were used in the study. One oral fluid and 5 random serum samples per pen were collected at 3, 5, 8, 12, and 16 weeks of age, and the sera were pooled by pen for testing. All samples were tested for PCV2 by real-time PCR and for antibodies by indirect fluorescent antibody test (for both anti-PCV2 IgG and IgA) and 3 ELISA assays (blocking ELISA, indirect ELISA, and IgG/IgM sandwich ELISA). PCV2 DNA was detected in oral fluid samples sporadically until 8 weeks and in all pens at 16 weeks. PCV2-specific IgG was detected in oral fluid samples at 3 weeks and persisted until 5 to 8 weeks in all sites. Anti-PCV2 IgG and IgA were detectable in oral fluid samples collected at 16 weeks from all of the pens at 1 site. The detection of PCV2 and anti-PCV2 antibody in oral fluid samples correlated positively with results on pooled sera, suggesting that oral fluids can be a cost-effective alternative to serum for herd monitoring of PCV2 infection.

Porcine circovirus-2 (PCV2) 는 돼지에서 여러 형태의 질병과 증후군의 발생과 관련이 되어있어 현재는 PCV-associated diseases (PCVAD)로 총괄적으로 분류된다. PCVAD에 의한 높은 경제적 손실 때문에 많은 양돈장들이 PCV2의 감염을 확인하기 위하여 혈청을 검사하고 있다. 하지만, 기존의 혈액채취법은 비용이 높고 많은 인력이 소요되므로 큰 규모의 병원체 검사에는 어려움이 있었다. 이에 본 연구에서는 혈액채취법을 이용한 돈군의 PCV2 검사법에 대한 대체방법으로 돈방 단위의 구강액채취법의 유용성을 실제 농장에서 평가하였다. 세 곳의 다른 양돈 농장들에서 각각 6개의 25두 규모의 돈방들을 선정하여 생후 3, 5, 8, 12, 16주에 돈방 마다 하나의 구강액과 5개의 혈청을 채취하였다. 모든 시료들은 real-time PCR을 이용하여 PCV2 DNA를 검사하였고 IgG 또는 IgA 간접형광항체 검사법및 세 가지의 ELISA 검사법 (blocking ELISA, indirect ELISA, and IgG/IgM sandwich ELISA)을 이용하여 PCV2에 대한 항체를 검사하였다. 구강액에서 PCV2 DNA는 8주까지는 간헐적으로 검출이 되다가 16주에는 모든 돈방에서 검출이 되었으며, 모체유래 PCV2 특이 IgG는 3주부터 검출이 되었고 모든 농장에서 5-8주까지 지속이 되었다. 16주에는 한 농장 (Site 1)의 모든 돈방에서 감염에 의한 IgG와 IgA가 검출되었다. 혈청에서의 PCV2 DNA와 PCV2 항체의 검출은 구강액에서의 검출과 높은 상관관계를 보였다. 따라서 구강액은 돈군의 PCV2 감염을 모니터링 하기 위해 혈청대신 사용할 수 있는 저비용, 고효율의 시료가 될 수 있을 것으로 사료된다.

Keywords

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