Poliovirus and Other Enteroviruses

Abstract

Human Papillomaviruses (HPVs) are small, non- enveloped double-stranded DNA viruses of the Papillomaviridae family. These viruses infect squamous epithelia including the skin and mucosae and are associated with a variety of clinical conditions ranging from common warts to intraepithelial dysplastic lesions, which may progress to invasive carcinoma in several anatomical sites. More than 40 HPV genotypes infect the anogenital mucosa causing sexually transmitted diseases; 15 of these can cause cancer of the cervix, the second most common cancer among women worldwide. In addition to cervical cancer, HPV is causally associated with less common cancers at other sites, including cancer of the vulva, vagina, penis and anus, as well as some cancers of the head and neck. HPV viruses are classified as either ‘high-risk’ or ‘low-risk’ types depending on their association with the development of cancer. HPV infection is most commonly transmitted through sexual activity. Other modes of transmission cannot entirely be ruled out, however. Indeed, there is evidence that HPV can survive well outside of its host to potentially be transmitted by non-sexual means. Recently, HPVs have been detected in urban wastewaters, and in surface waters as well, demonstrating that epitheliotropic viruses can find their way into sewage, and subsequently other water environments. The presumed source of contamination is the washing of skin and mucous membranes, but recent detection of HPVs in stool specimens suggests that they may also reach wastewaters as a result of shedding in the feces. HPVs are not classic waterborne pathogens and their presence in water environments is a relatively recent discovery. The present chapter describes the state of the art on human papillomaviruses and their presence in water environments. Unfortunately, since HPVs have only recently been identified as potentially waterborne pathogens, little data are available on the fate of these viruses in water environments and their potential for waterborne transmission. The first section of the chapter covers the epidemiology of HPV infections, clinical manifestations and associated diseases, diagnosis, treatment, and prevention. The second section focuses on the occurrence of these viruses in different water environments. Finally, data on inactivation of HPVs is addressed.