Regional Cross-Sectional Based Study and Associated Risk Factors of Porcine Circovirus 2 in Nigerian Pigs

Porcine circovirus 2 (PCV2) is a swine viral pathogen of substantial economic importance in pig farming globally. However, large-scale surveillance is needed to determine its prevalence and associated risk factors in the Nigerian pigs. We conducted molecular-based surveillance and mapping of PCV2 in southwest Nigeria to assess its prevalence and spatiality. Six hundred forty-eight individual fecal samples were collected from the different age groups of pigs from 67 farms in three southwest states. The polymerase chain reaction technique was used to screen the samples with a specific primer pair. The viral prevalence was determined at individual animal and farm levels. Overall, 145 out of 648 samples (22.4%) and 49/67 farms (73.1%) tested positive for PCV2. The highest prevalence of PCV2 was observed in Oyo State (63/185, 34.1%) and in growers (66/145, 45.5%). Restricting visitors' entrance to the farm was found to be strongly protective for PCV2 (AOR 0.122; p=0.007; 95% CI; 0.027-0.564), while not having a quarantine protocol (AOR 4.445; p=0.041; 95% CI; 1.067-18.5280) and reporting coccidiosis as a common disease encountered (AOR 14.340; p=0.007; 95% CI; 2.094-98.203) on the farm were significant risk factors identified to be associated with the presence of PCV2. This study revealed a higher prevalence of PCV2 in Nigerian swine herds than expected and presented significant spatial clustering of infection in the studied region. It has also highlighted the risk factors driving its spread in the studied area. The research findings underscore the need for a policy decision to promote PCV2 vaccination in the country, which is currently not in place. The availability and use of the PCV2 vaccines, in addition to effective biosecurity measures, will help to mitigate the virus and its associated diseases in the country for sustainable and profitable pig farming, which holds vast potential in solving the problem of hunger and poverty.