Molecular characterization of current field isolates of zoonotic parapoxviruses and their growth characteristics

Abstract

Parapoxviruses (PPVs), including Bovine papular stomatitis virus (BPSV), Pseudocowpox virus (PCPV), and ORF virus (ORFV), are zoonotic pathogens affecting wild and domesticated ruminants. Between 2023 and 2024, erosive papules and ulcers on the lips, nose, and tongue of calves, as well as proliferative oral lesions in lambs, were reported in various Turkish regions. In two geographically distant beef herds, nodular hand lesions in animal handlers indicated zoonotic transmission. Suspected samples were confirmed by PCR using B2L genespecific primers. Three isolates representing BPSV, PCPV, and ORFV were sequenced and compared to global data. PCPV showed closest similarity to strains from Bangladesh and Finland, while BPSV was most similar to strains from China and Iran. Virus isolation was attempted on four cell lines: primary fetal lamb kidney (PLK), Madin-Darby bovine kidney (MDBK), sheep fetal thymus (SFT-R), and African green monkey kidney (VERO). PLK cells showed 100 % isolation success for all three viruses. In serial passages, ORFV replicated best in PLK cells, consistently yielding the highest viral titers. This study provides molecular and phylogenetic characterization of currently circulating zoonotic PPVs in T & uuml;rkiye and compares their in vitro replication efficiency. PLK cells were identified as the most sensitive and productive system, particularly for ORFV, which is of interest due to its immunomodulatory potential.