SHIC Updates PCV3 Fact Sheet – Case Definition and On-farm Epidemiology Needed

An updated fact sheet on porcine circovirus 3 (PCV3) has been posted on the Swine Health Information Center (SHIC) website containing the latest information available. PCV3 is a newly detected pathogen of swine. Although most cases have been detected subclinically, PCV3 is also associated with clinical signs similar to those caused by porcine circovirus 2 (PCV2). Individual case definitions have been proposed for PCV3-associated reproductive disease and systemic disease to standardize diagnostic criteria. Work continues at veterinary diagnostic labs (VDLs) where a case definition is being developed. The VDLs are collecting clinical signalment from practitioners who have a PCV3 diagnosis in clients’ herds and are combining it with diagnostic test result qualifications. When this work is finished, communicated in the industry, and generally accepted, SHIC will then move on research priorities and needs. Research will further characterize the clinical and economic outcomes of a PCV3 diagnosis. Case definition completion and beginning of research are expected yet in 2021. Fact sheet updates are part of SHIC’s mission to protect the health of the US swine herd, providing guidance and resources for producers, practitioners, and diagnosticians who are on the front lines of swine health concerns is paramount.

PCV 3 has been associated with reproductive failure, porcine dermatitis and nephropathy syndrome (PDNS), and multi-systemic inflammation. However, only a few studies have demonstrated the presence of PCV3 in lesions. Anecdotally, PCV3 has been detected in neurological, respiratory, and enteric cases, but causation has not been established. In pathogenicity studies, PCV3 inoculation does not consistently lead to development of clinical disease. Individual diagnostic criteria proposed for PCV-3-reproductive disease (PCV-3-RD) include late reproductive problems and higher perinatal mortality, multi-systemic lymphoplasmacytic to lymphohistiocytic perivascular inflammation, and moderate to high amount of PCV-3 genome in damaged tissues. Individual diagnostic criteria proposed for PCV-3-systemic disease (PCV-3-SD) include weight loss, rough hair, neurological signs, multi-systemic lymphoplasmacytic to lymphohistiocytic perivascular inflammation, and moderate to high amount of PCV-3 genome in damaged tissues

PCV3 is found in wild and domestic pigs. Antibodies to PCV3 have been detected in dogs, cattle, and mice. PCV3-positive mosquitoes have been found. Wild ruminants and ticks may also be reservoirs. PCV3 is found in many swine-producing regions of the world. Epidemiological studies have found that infection is widespread, with prevalence up to 100%. Little is known about the course of natural infection. A few studies have shown that prevalence is highest in piglets/weaners and decreases with age, but PCV3 has been detected in pigs up to 23 weeks-of-age.

SHIC, launched in 2015 with Pork Checkoff funding, continues to focus efforts on prevention, preparedness, and response to novel and emerging swine disease for the benefit of US swine health. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. SHIC is funded by America’s pork producers to fulfill its mission to protect and enhance the health of the US swine herd. For more information, visit http://www.swinehealth.org or contact Dr. Sundberg at psundberg@swinehealth.org.