Lack of Evidence on the Susceptibility of Ticks and Wild Rodent Species to PCV3 Infection

Abstract

Porcine circovirus 3 (PCV3) is an emerging virus, first detected in 2016 and widespread in the swine industry. Although not considered a primary pathogen, PCV3 is potentially linked to several clinical conditions that threaten swine farming. Wild boars are considered the main reservoir species for PCV3 infection in the wild, but recent detection in roe deer, chamois and associated ticks has complicated our understanding of its epidemiology. Much emphasis has been placed on ticks, as competent vectors, and wild rodents, which typically feed immature tick stages. The aim of this study was to clarify whether wild rodent species and associated ticks are susceptible to PCV3 infection and involved in its spread. Wild small mammals’ serum samples and hosted ticks were, therefore, collected from areas where no wild boars were present and tested by PCR, targeting the PCV3 rep gene. A total of 90 yellow-necked mice (Apodemus flavicollis), two wood mice (A. sylvaticus), 26 bank voles (Myodes glareolus) and 262 Ixodes spp. ticks were investigated. PCV3 DNA was not detected in serum or in tick samples. These findings support the hypothesis that the investigated species do not have an actual role as PCV3 reservoirs. Further studies would be necessary to state whether these species, or others that we did not test, are involved in PCV3 infection spread—in particular when susceptible species share the same habitat.

Revisiting Porcine Circovirus Infection: Recent Insights and Its Significance in the Piggery Sector

“…Like PCV2, PCV3 can be transmitted both horizontally and vertically [ 201 ]. The primary mode of viral transmission is through the horizontal route, involving direct contact [ 202 ]. PCV3 has been detected in various parenchymal tissues, blood, oral fluids, nasal swabs, feces, and semen [ 17 , 203 ].…”

Detection and Complete Genomic Analysis of Porcine circovirus 3 (PCV3) in Diarrheic Pigs from the Dominican Republic: First Report on PCV3 from the Caribbean Region

“…PCV3 has been found to be highly prevalent and endemic in wild boars, with evidence for long-lasting infection, suggesting their role as potential reservoirs and a source of the virus to domestic pigs [ 2 , 10 , 11 , 12 , 13 ]. Interestingly, PCV3 has also been detected in various non- Suidae species (cattle, chamois, dogs, donkeys, rodents, and roe deer), and in arthropods (mosquitoes and ticks), although the role/s of heterologous host/s or vectors in transmission of PCV3 remain to be properly interpreted [ 2 , 10 , 14 , 15 , 16 , 17 ].…”