KI and WU Polyomaviruses in urine, vaginal and nasopharyngeal swabs of Portuguese individuals

KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) are two ubiquitous human viruses, for which the main mode of transmission remains unclear. Respiratory and fecal-oral routes have been pointed as potential modes of transmission, mainly based on studies conducted among children with acute respiratory illnesses and immunocompromised adults. Nevertheless, limited information exists regarding healthy individuals. Sexual route has recently been hypothesized for other human polyomavirus, however, it has not been investigated for KIPyV and WUPyV. This study aimed to evaluate the presence of these viruses in different biological samples of Portuguese individuals, as possible sources of viral particles. The presence of KIPyV and WUPyV DNA was evaluated by real-time PCR in 1016 biological samples, each obtained from a different individual. A total of 123 urine samples, 600 nasopharyngeal swabs and 293 vaginal samples were analysed. KIPyV DNA was detected in nasopharyngeal secretions of 15 (2.5%) individuals, comprising ten children (3.3%) and five adults (1.7%)( p =0.191). Children under the age of ten (4.5%) were the group with the higher frequency of detection ( p =0.04). WUPyV DNA was detected in nine (1.5%) samples, seven from children (2.3%) and two from adults (0.7%)( p =0.176), with higher detection rate in children younger than ten years (3.4%)( p =0.02). KIPyV and WUPyV genomes were not detected in any of the evaluated urine and vaginal samples. The detection of KIPyV and WUPyV in respiratory secretions of individuals without respiratory symptoms, especially children under 10 years of age, suggests respiratory shedding of viral particles, which could be involved in infection acquisition. The results obtained further suggest that urine and vaginal secretions are unlikely to be sources of viral particles in the studied group. • KIPyV and WUPyV were detected in respiratory secretions of asymptomatic individuals • KIPyV and WUPyV were mostly detected in children under 10 years old • Respiratory secretions may be potential sources of KIPyV and WUPyV viral particles • KIPyV and WUPyV genomes were not detected in urine and vaginal secretions