Warts: what are the Viruses causing them ?

They are called HPV (Human Papillomavirus). They have the following characteristics:
–Double-stranded DNA chain
-no viral envelope
-replicate in the nucleus of the host
-is species specific (humans)
–capsids are made of the late replication proteins proteins L1 and L2
-early proteins such as E6 and E7 are early replication proteins and are viral oncognes which bind tumor suppressor genes  p53 and pRB

Over 150 subtypes have been identified: they differ in the L1 capsid proteins
-Different subtypes vary according to the location of warts (hands, feet, cervix, mucous membranes…). Only some are susceptible to neoplastic change

How to find them
-In situ hybridization
-Southern blot hybridization
-Hybrid capture assay (from pap spears of the cervix)
–Polymerase Chain Reaction (PCR) from lesions which allows determination of subtype.

Transmission
-Through microabrasions as the virus can enter mitotically active keratinocytes in the basal layer (Stratum Basale (SB))

Difference between Cancerous (oncogenic) and Non-Cancerous warts
-HPV DNA integrates into the DNA (16, 18, 31,33, 45, 52, 58)
-Common ones do not normally integrate the main host’s DNA (Busckhe Lowenstein tumor would be an exception as DNA does not integrate and the phenotype is outwards (exophytic) growth)

Bibliography: u055 Tyring SK – Warts. U003 – AAD 2016 – Washington DC, United States USA