General Characteristics:
The Papilloma virus is a double-stranded DNA virus with an incubation period of usually 4-8 weeks, or possibly lasting months or decades. HPV infects stratified epithelial cells and replicates within the nucleus. (7.)
Means of Transmission:
Direct contact- This virus is the most common sexually transmitted disease (STD), in which infection can occur through micro-abrasions of the skin or mucosa during sexual intercourse. (9.) It is estimated that 75% of sexually active men and women have been infected with genital HPV sometime during their life. (6.) Replication produces protein capsids in the upper levels of the epithelium where dying cells can also serve as vectors. (4.)
Indirect contact-Some researches suggests that transmission of the virus via fomites (towels or underwear) can take place, but more research on HPV transmission is needed. (6.)
Vertical transmission-The mother may transfer the disease to her child during birth. Although the possibility is rare, it can cause recurrent laryngeal papillomatosis (warts in the throat) for that child. This can lead to breathing problems, as warts grow to large for adequate airflow. (6.)
Reservoirs:
The Papilloma virus is species-specific; humans can harbor and transmit the HPV to others without exhibiting any signs or symptoms. (9.)
History:
The virulence of human warts, associated with HPV, was first identified in 1907. (8.) HPV infected rabbit cells, from warts, were first studied by Richard Shope in 1933 and called, °Shope Papilloma Virus°± named for the man who was the first to isolate the virus, and Papilloma is the clinical term for warts. (3.) Techniques to grow the Papilloma virus in vitro were unsuccessful and the virus remained largely unstudied until the 1970°Øs. Today much of our current knowledge comes from the Bovine Papilloma Virus (BPV). (8.)
Etiologic agent for:
Cervical, vulva, anal, and penile cancers. HPV is also the causing agent for genital warts. (9.)
Signs and symptoms:
There are over 100 subtypes of HPV that cause warts on specific body parts, but most infections cause little or no symptoms and usually go undiagnosed. Skin warts are divided into flat warts (superficial), planter warts (deeper), and genital warts (condylomas). Condyloma warts may be so small as to be invisible to the eye or can be seen as flesh or pink colored raised bumps. Some warts can grow very large interfering with urination, defecation and may cause pain during intercourse. (8.)
Microbial Virulence:
Virulence is due in part to the protective viral capsid and the virus's ability to inhibit tumor suppressor genes. (5.) Also take into consideration the immune status of the host. (9.)
Tests for identification:
A hand lens or colposcopy may be used to identify infection by magnification of cervical or vaginal tissues, and a Pap smear may also reveal precancerous conditions of the cervix. The Food and Drug Administration recently approved the Hybrid Capture II HPV test, which is to be used when a Pap test comes back as inconclusive. This test is a DNA-based technology able to detect 13 high-risk types of HPV. (6.)
Treatment:
There is currently no known treatment. (1.)
Prevention, control, and research:
Prevention is accomplished through public and provider awareness, efficacy of behavior changes (reduction in partner number), the use of condoms, (9.) monogamy, celibacy (6.) and the maintenance of a healthy life style including exercise. (7.) Control methods include; chemical, freezing or laser treatments of infected tissue areas (warts). (1.)Research is on going, evident by 3M's new therapeutic approach to genital warts. The use of Aldara cream, discovered by 3M pharmaceuticals, has recently been approved for use and is a new form of drug labeled as an immune response modifier. (2.)
References
(1.) http://healthlink.mcw.edu/article/946071831.html
(2.) http://www.aomc.org/hpv.html
(3.) http://www.vectorsite.net/v2001m11.html
(4.) http://www.arhp.org/arhpframe.html
(5.) http://www.medinfo.ufl.edu/year2/mmid/bms5300/bugs/hpv.html
(6.) http://www.plannedparenthood.org/library/sti/011120_hpv.html
(7.) http://www.colby.edu/health.serv/health_matters/hpv.html
(8.) http://www.tulane.edu/%7Edmsander/WWW/335/Papovaviruses.html
(9.) http://www.cdc.gov/nchstp/dstd/Fact_Sheets/FactsHPV.htm