
Full text loading...
Papillomaviruses and Polyomaviruses, Page 1 of 2
< Previous page Next page > /docserver/preview/fulltext/10.1128/9781555815905/9781555813642_Chap75-1.gif /docserver/preview/fulltext/10.1128/9781555815905/9781555813642_Chap75-2.gifAbstract:
Until recently, papillomaviruses and polyomaviruses were grouped together as papovaviruses, but they are now classified as two distinct families. Human papillomaviruses (HPVs) are strictly epitheliotropic viruses that infect squamous epithelia of the skin and mucous membranes. The expression of viral genes is tightly linked to the stages of cellular differentiation. The cervical squamous intraepithelial lesions (SIL) that may result from HPV infections can be detected in Pap smear screening programs and treated effectively. Epidermodysplasia verruciformis (EV) is often familial. Clinically the warts are flat or are in the form of reddish brown macular plaques. Immunization of humans by intramuscular injection with VLPs results in a robust antibody response, with antibody titers far exceeding those resulting from natural infections. A positive test indicates productive infection with any of the HPVs. The infecting HPV type cannot be specifically diagnosed by the test because type-specific antisera are not available. In humans, human polyomavirus JC virus (JCV) is the etiologic agent for the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML), while BK virus (BKV) infection is associated with urinary tract infections and nephropathy. Potent antiretroviral drugs have effectively reduced plasma HIV viral loads and increased CD4 cell counts, which could potentially lead to a decreased susceptibility to opportunistic infections such as PML. The antigen responsible for the hemagglutinating activity is located on the Vp1 capsid protein. Diagnostic testing at present relies heavily on DNA-based technologies such as in situ DNA hybridization and quantitative PCR.