Identification of porcine circovirus type 3 (pcv3) in Thailand and its associated syndrome

Abstract

Porcine circovirus type 3 (PCV3) is a recently identified swine virus with currently unknown pathogenesis. To date, PCV3 has been found in many countries, indicating the wide spread of the virus. Therefore, there is an urgent need to clarify the detrimental role of PCV3. To better understand how PCV3 might influence the pig industry, various perspectives in swine production cycle should be considered. In this study, firstly, PCV3 was identified for the first time in Thailand. The study also showed that PCV3 has existed in the Thai pig population as early as 2005, suggesting that the virus might have long been a part of swine health problems in Thailand. To gain more information about PCV3 pathogenesis, a series of investigation in different phases of swine production cycle were conducted. The results showed that in gestating pigs, the presence of PCV3 was associated with abortion. Moreover, sow infection could also lead to vertical transmission of multiple routes. PCV3 shedding in colostrum was identified for the first time in this study. Consequently, early infection in piglets by vertically transmitted PCV3 might also lead to horizontal transmission later. An investigation on a farm with early PCV3 infection showed that PCV3 was associated with porcine respiratory disease complex (PRDC) in grower pigs. In conclusion, this study demonstrated that PCV3 could show different roles in each phase of the swine production cycle. Management of gilt/primiparous sows as an initial control strategy against PCV3 is also discussed in this study.