Bio 311

Sexually Transmitted Diseases

Lecture 6

The following information was taken from “The Sexually Transmitted Diseases: A current Approach” by George A. Wistreich, (1992) Wm.C. Brown Publishers, Dubuque, IA and from the Websites given below.

http://www.ashastd.org/stdfaqs/statistics.html

Hepatitis Viruses

http://digestive.niddk.nih.gov/ddiseases/pubs/viralhepatitis/index.htm

http://www.hepatitisresources-calif.org/hepfi/living/liv_diagnosis.html

• Hepatitis refers to the inflammation of the liver. Symptoms of hepatitis include jaundice, fatigue, abdominal pain, loss of appetite, nausea, vomiting, diarrhea or constipation, low-grade fever and headache. However, some individual may not experience any symptoms.
• Viral Hepatitis can be caused by one or more of the hepatitis viruses, these include hepatitis A, B, C, D and E.
• The genome of these viruses consists of DNA.
• Hepatitis A virus (HAV) is transmitted through food or water contaminated with feces from an infected person. People who are highest at risk include international travelers and people who live with or have sex with an infected person.. Hepatitis due to HAV infection can be prevented by the HAV vaccine and avoiding high-risk activities. This type of infection is resolved on its own, that is the immune system fights the infection.
• Hepatitis B virus (HBV) is transmitted by coming in contact with infected blood, through sex with infected person and from infected mother to child during birth. People at risk include the above, IV drug users, health care workers, people who received a transfusion of blood or blood products before July 1992 or clotting factos made before 1987, and international travelers. The disease due to HBV can be prevented with HBV vaccination. For chronic hepatitis treatment, alph interferon, peginterferon, lamivudinem ior adefovir dipivoxil can be used. Acute cases usually resolve on their own.
• Hepatitis C virus (HCV) is transmitted through contact with infected blood; less commonly, through sexual contact and childbirth. People at risk include injection drug users, people who have sex with an infected person, peole who have multiple sex partners, hearlth care workers, infacts born to infected women, hemodialysis patients, and people who receive transfusion of blood or blood products before July 1992 or cotting factors made before 1987. There is no vaccine for HCV. The only way to prevent the disease is to reduce the risk factors. For chronic HCV infection, treatment with peginterferon alone or combination treatment with peginterferon and ribavirin is used. For Acute treatment that does not resolve on its own within 2-3 months, drug treatment should be used.
• Hepatitis D virus (HDV) is transmitted through contact with infected blood. This disease occurs only in people who are already infected with HBV. People with HBV are at risk. People who have hepatitis B are also at risk if they have sex with a person infected with hepatitis D or if they live with an infected person. Also at risk are people who received a transfusion of blood or blood products before July 1992 or clotting factors made before 1987. To prevent HDV, immunization against HBV for those not already infected is required. In addition, avoiding high risk behavior is required. Treatment with alpha interferon is required for chronic hepatitis.
• Hepatitis E virus (HEV) is transmitted though food or water contaminated by feces from an infected person. This disease is uncommon in the USA. International travelers, people living in areas where HEV outbreaks are common and people who live or have sex with an infected person are at risk. There is no vaccine for HEV. However, avoiding risk factors will prevent the disease. HEV infection usually resolves on its own over several weeks to months.

Hepatitis B Virus (HBV)

• HBV follows the same routes of transmission as HIV and is found in over 90% of persons with AIDS.
• HBV has been shown to interact with hepatits D virus and to change normal liver cells into cancerous ones.
• HBV can infect lymphocytes and remain in these cells without destroying the infected cell. In this protected arrangement, the immune system of the infected individual is powerless in dealing with disease agents.
• HBV has DNA as its genome. The virus is made up of an outer shell known as the hepatitis B surface antigen (HBsAg), and an inner shell known as the hepatitis B core antigen (HBcAg), which holds the viral DNA. A subunit of the core antigen known as the hepatitis “Be” antigen (HBeAg) is of value as an indicator of an active infection.
• Transmission of HBV is similar to those found with HIV. These viruses are found in body fluids such as blood, semen and saliva. Principally, they include homosexual or heterosexual sexual activities, exposure to virus-contaminated injection material by intravenous drug users, and viral transmission from an infected mother to her fetus or newborn. In addition, health care professionals such as dentists, surgeons, and medical laboratory workers are at an increased risk to HBV infection because of possible exposure to contaminated blood during the performance of their respective jobs.
• Symptoms of HBV infection appear after an incubation period of 45 to 160 days. Only about 50% of HBV infections present evidence of disease. The symptoms include weakness, jaundice, fever, loss of appetite, abdominal pain, liver tenderness, nausea, vomiting and constipation. Infected individuals usually pass dark-yellow to orange colored urine, and light colored stools.
• The short term or acute infection generally will run its course in 3-4 weeks. Some symptoms may last for as long as 6 months.
• The chronic form of the disease is when the infection has persisted longer than 6 months. Complications of various kinds can develop with the chronic state. They include liver failure, a breakdown of liver structure (know as cirrhosis) and cancer.
• Newborns infected by their mothers may be without symptoms. If symptoms do occur, these will include weakness, appetite loss, nausea, abdominal pain, jaundice and weight loss. Once infected, these infants may continue to harbor HBV for a long time and eventually develop the complications mentioned earlier.
• Diagnosis of hepatitis infection can be made based on the evidence of jaundice, dark orange urine, and an enlarged and tender liver. Confirmation of HBV infection however, involve the analysis of blood for evidence of liver damage and for the presence of specific parts of the virus such as HBsAg and antibody for the hepatitis B core antigen (HBcAg).
• Preventing HBV infection is possible if specific HBV antibodies known as hepatitis immunoglobulins are injected within 48h after exposure. HBV can also be prevented by the HBV vaccine (as mentioned above).

Herpes Viruses

• Five major herpes viruses are capable of infecting humans. These include herpes simplex virus (HSV) type 1 and herpes simplex virus type 2. HSV-1 usually is found above the waist and causes most cold sores or fever blisters, while HSV-2 seems to prefer regions below the waist and is responsible for about 80% of genital herpes. It is also possible for either virus to take the other’s place. Type 2 can cause cold sore, and type 1, which is not usually connected with sex, can also infect the genitalia. Each virus can be passed from one body location to another during oral-genital sex, for example.
• The other herpes viruses are varicella-zoster virus which causes both chicken pox (varicella) and an infection of nerves called shingles (zoster); cytomegalovirus which is responsible for a variety of infections of the eye, respiratory system and the gastrointestinal tract; and Epstein-Barr virus known for its ability to cause a mononucleosis like illness, in which an infected person develops fever, sore throat, and swollen lymph nodes. The varicella-zoster and Epstein Barr viruses are usually not spread by sexual contact. Kissing and sharing contaminated forks and spoons are linked to Epstein-Barr infections. These viral disease agents as well as the other herpes viruses are commonly found in persons with HSV infections and poorly functioning immune systems.
• The term herpes comes from the Greek “to creep.”
• The herpes simplex viruses are large DNA containing disease agents that readily infect the surface (mucosal) linings of various body passages and cavities such as the mouth and vagina.
• The herpes simplex viruses, as well as other herpes viruses, do not survive well outside the human body. They can be readily inactivated by ultraviolet light (sunlight) and a variety of chemicals such as those found in common disinfectants.

Cold Sores or Fever Blisters

http://www.nlm.nih.gov/medlineplus/ency/article/002088.htm

• Cold Sores or Fever Blisters are caused by Herpes Simplex type 1 infection. The mouth is the most common site of HSV-1 infection. However, breasts, the surface of the eye, the fingers, the anus, or the rectum can also become infected. HSV-1 may also cause genital herpes.
• HSC-1 is spread thought kissing an infected person, or physical contact with contaminated eating utensils, drinking glasses, or toothbrushes.
• Symptoms develop about 3-7 days following contact with the virus, painful blisters appear on and below the tongue and other mouth parts. These blisters, which may run together, eventually break, forming open, oozing sores or ulcers. Within a few days lesions also appear on the lips and about the chin, and may spread to the throat and tonsils. Crusts eventually form over the ulcers and the infection episode comes to an end and healing begins. The entire sequence from blisters to crusts and the shedding of virus lasts about 12-14 days.
• Reactivation of HSV-1, known as recurrence, may occur at any time by mechanisms that are not completely understood. Several diverse and general factors induce viral reactivation. These include high fever, stress, excessive exposure to the sun and wind, severe bacterial infections, colds, and menstruation.
• During reactivation viral multiplication occurs in nerve tissue. This event is followed by the new viruses traveling along nerves to mucosal or skin surfaces where they cause a new infection. With each recurrence the body’s immune system organizes a fierce and usually effective attack on the activated viruses. Unfortunately, some viruses are able to escape this attack and hide in the body cells, thus being protected from the immune system. This is one reason why a permanent cure has not been found.
• Laboratory diagnosis of HSV-1 infections include microscopic examination, virus cultivation, and the direct identification of viral parts known as antigens. In addition, blood tests to detect antibodies to HSV-1 also can be used.

Genital Herpes

http://www.niaid.nih.gov/factsheets/stdherp.htm

http://www.ashastd.org/hrc/educate.html

• HSV-2 infection is acquired from a person shedding the virus at the time of sexual intercourse or contact with genital secretions. The practice of anal intercourse has resulted in an increasing number of cases of primary herpes proctitis, an inflammation of the rectum and anus.
• Itching and soreness of the genitalia are primary symptoms of HSV-2 infection. Many infected individuals also experience enlarged and tender lymph nodes in the groin and surrounding areas, fever, headache, and general discomfort. Red spots or macules, blisters or vesicles and ulcers develop next. The ulcers eventually come to contain pus. Crusting, scab formation, and finally healing occurs.
• In men, lesions occur on the glans, prepuce and penile shaft. Scattered lesions may also develop on the scrotum, thigh, and buttocks.
• In women, vesicles and other lesions occur on the labia and spread to the inner thigh surfaces. Women also have a vaginal discharge, an inflammation of the cervix and experience more painful lesions in general.
• Recurrences also occur with HSV-2. Compared to primary infections, recurrent episodes are usually shorter and milder in relation to symptoms and virus shedding. The actual lesions are fewer and heal more quickly.
• Genital herpes often can be diagnosed on the basis of the lesions found on physical examination. However, laboratory confirmation is needed. Laboratory examination includes looking for multinucleated giant cells with a microscope, and the isolation of the virus in tissue culture. Pap smear is of particular value in diagnosing HSV-2 infection.
• The treatment of HSV-2 includes the use of the antiviral drug acyclovir. Treatment with this drug shortens the course of the infection, but does not reduce the number of recurrences.
• Genital herpes is thought to be of potential importance in the development of cervical cancer.
• Abstention from sexual interactions is required to prevent the transmission of virus. Condoms are not 100% effective in the prevention of the spread of the virus.

Cytomegalovirus

http://www.cdc.gov/ncidod/diseases/cmv.htm

• A cytomegalovirus (CMV) infection typically causes an enlargement of infected cells with the development of distinctive structures, called inclusion bodies, in their nuclear and cytoplasmic regions.
• Cytomegaloviruses currently are the major cause of birth defects, hearing loss, and mental retardation in congenitally infected infants.
• Maternal infection plays and important role in the transmission of CMV to newborns. CMV is spread largely by contaminated breast milk and close personal contact with infected individuals. CMV is also transmitted sexually. However, it can also be spread among adults by close personal contact, contaminated blood, and organ transplants.
• In congenitally infected newborns, CMV infections may produce symptoms ranging from fever to severe brain damage and neurological abnormalities. Other effects that may occur include enlarged liver, spleen, inflammation of the eye, and small purplish, blood-filled spots on the skin.
• Diagnosis of CMV includes virus isolation, electron microscopy blood tests for specific antibodies, and detection of viral nucleic acid.
• There is not effective treatment.

Human Papilloma Virus (Genital Warts)

http://www.ashastd.org/hpvccrc/quickfaq.html

http://www.niaid.nih.gov/factsheets/stdhpv.htm

• Papilloma viruses are a group of small deoxyribonucleic acid (DNA) viruses, which cause a class of harmless, or benign tumors of the skin or mucous membranes referred to as papillomas. Such tumors include warts and condylomas.
• Many warts are generally harmless, local growths, which shrink and disappear after a time. Their initial formation is probably caused by some injury to the skin surface which allows the human papilloma virus (HPV) to invade the deeper-lying skin-producing layers. The viral infection stimulates cell growth and reproduction and the eventual formation of wart.
• There are over 70 different types of HPVs. Only a small number of HPVs are generally associated with genital warts. Genital warts or condylomata acuminata are generally associated with HPV types 6,11,16,18 and 31 primarily, although others also cause genital HPV infections.
• HPV infections are spread through scratches of the skin, by sexual contact and a baby’s passage through an infected birth canal. HPVs also have been transmitted by oral sex.
• Evidence exists that implicates specific HPV types as causes of certain genital cancers. A significant number of cervical cancers have been found to contain HPV types 16 and 18. These 2 viral types also have been reported to be present in cancers of the vulva, vagina, and penis.
• The incubation period varies from several weeks to months.
• In men and women, the warts are generally soft, fleshy and contain small blood vessels. Genital warts are more common in uncircumcised men than in circumcised men. In women, they are frequently fond at the vaginal entrance and on the labia, the urethra and the cervix.
• Involvement of the perianal and surrounding regions may also occur.
• Newborns infected during the time of birth may develop the condition known as juvenile-onset respiratory papillomatosis. In this infection, growths or papillomas develop in the throat, and ma cause hoarseness or may interfere with normal breathing. The condition may appear within a few months, or ten or more years after birth. Removal of the growths is necessary to keep the airway of the infected newborn clear.
• A colposcope, which is a magnifying optical instrument, is of value in detecting HPV infection in women. The pap smear also is of major importance. A more specific diagnosis of HPV infection can be made with the detection and study of viral nucleic acid in specimens from infected individuals.
• Treatment of genital warts include destroying the tissue by freezing, heat, corrosive chemicals or electrical current (invasive techniques). Alternatively, noninvasive techniques include the use of tissue-destroying chemicals such as trichloroacetic acid, agents that interfere with tissue reproduction such as podophyllin and related materials and antiviral substances such as the interferons.

Molluscum Contagiosum (Pox-Virus)

http://www.ashastd.org/stdfaqs/molcon.html

• Molluscum contagiosum is cause by a DNA pox virus. The virus can be spread both sexually and non-sexually. The nonsexual form of the disease appears to be found primarily among children. It is spread by direct contact with the skin of infected persons and/or articles contaminated by such individuals, such as gymnastic equipment and towels.
• The general tumor-like growths, which range in color from a pearly white to a light pink, mainly develop on the genitalia, face, and hands of the infected individual within 2-7 weeks of exposure. A whitish paste easily can be squeezed from a central depression in these tumors.
• The diagnosis of this disease usually is made on the finding of the pearly white growths. However, microscopic examination of specimens may be necessary to show the presence of the virus or evidence of infection.
• Treatment of this disease is necessary, not only to relieve the discomfort experienced by some individuals, but also to prevent further spread. Treatment generally involves the removal of the growths by chemicals or by localized freezing.