A large spectrum of alpha and beta papillomaviruses are detected in human stool samples

Human papillomavinises (HPVs) have been detected in urban wastewaters, demonstrating that epitheliotropic viruses can find their way into sewage through the washing of skin and mucous membranes. Papillomavirus shedding through faeces is still an unexplored issue. The objective of the present study was to investigate the presence of HPVs in stool samples. We analysed 103 faecal specimens collected from hospitalized patients with diarrhoea using validated primers able to detect alpha, beta and gamma HPVs. PCR products underwent sequencing analysis and sequences were aligned to reference genomes from the Papillomavirus Episteme database. A total of 15 sequences were characterized from the faecal samples. Thirteen samples (12.6%) were positive for nine genotypes belonging to the alpha and beta genera: HPV32 (LR, alpha 1), HPV39 (HR, alpha 7), HPV44 (LR, alpha 10), HPV8 (beta 1), HPV9, HPV23, HPV37, HPV38 and HPV120 (beta 2). Two putative novel genotypes of the beta genus, species 1 and 2, were also detected. The tissue(s) of origin is unknown, since faeces can collect HPVs originating from or passing through the entire digestive system. To our knowledge, this is the first investigation on the occurrence and diversity of HPVs in faecal samples. Results from this study demonstrate that HPVs can find their way into sewage as a consequence of shedding in the faeces. This highlights the need for further studies aimed at understanding the prevalence of HPV in different water environments and the potential for waterborne transmission.