HIV-2 is closely related to, but not identical, to HIV-1. HIV-2 is found predominantly in West Africa, where in some areas it is the predominant HIV infection. In other areas it may occur with less frequency than HIV-1. It has also been found in low frequency in Central, East, and Southern Africa. It is spread […]
The HIVs are retroviruses; their genetic information (genome) is composed of RNA rather than the usual DNA. To reproduce, the virus uses an enzyme known as reverse transcriptase to produce a DNA copy of its genetic RNA and incorporates this material into the host cell genetic material. Some of the copied viral genome also exists […]
CMV is part of the herpesvirus group (herpes simplex, CMV, Epstein-Barr, and varicella-zoster). CMV infection is widespread, since serologic evidence of infection varies from about 30% to over 90% between different geographic areas and population groups. In general, there is lower incidence in Western European nations and many areas of the United States. The two […]
The Epstein-Barr virus is a member of the herpesvirus group and is reported to infect 80% or more of the U.S. population. It is thought to be spread from person to person, most likely through saliva, with the majority of infections occurring in childhood, adolescents, and young adults. The EBV infects B-lymphocytes. In common with […]
Hepatitis D is also called “delta hepatitis.” It is a partially defective virus that must enter the hepatitis B virus in order to penetrate and infect liver cells. Therefore, a person must have HBV present, either as a carrier or in clinical infection, in order to acquire HDV infection. When HBV infection is over, HDV […]
This is a NANB virus with an incubation period, clinical course, and epidemiology similar to that of HAV. HEV is currently thought to be a calcivirus. In 1994 no HEV antigen or antibody tests are commercially available, although several antibody tests using homemade reagents have been reported. Sensitivity of the tests is similar to that […]
After serologic tests for HAV and HBV were developed, apparent viral hepatitis nonreactive to tests for HAV and HBV or to other viruses that affect the liver was called non-A, non-B (NANB) hepatitis virus. Eventually, hepatitis D virus was discovered and separated from the NANB group. It was also known that NANB represented both a […]
HBV was originally called “serum hepatitis,” or “long-incubation hepatitis,” and has an incubation period of 60-90 days (range, 29-180 days). HBV is found in blood and body secretions. Infection was originally thought to be limited to parenteral inoculation (blood transfusion or injection with a contaminated needle). Although this is still the major source of infection, […]
Hepatitis A virus (HAV) Hepatitis A virus (HAV) was originally called “infectious hepatitis” or “short-incubation hepatitis,” and has an incubation period of 3-4 weeks (range, 2-6.5 weeks). HAV is highly contagious. During active infection it is excreted in the stool and is usually transmitted via fecal contamination of water or food. However, infection by fecal […]
Rubella (German measles) is a very common infection of childhood, although primary infection can occur in adults. The major clinical importance of rubella is maternal infection during pregnancy, which may produce the congenital rubella syndrome in the fetus. The congenital rubella syndrome includes one or more of the following: congenital heart disease, cataracts, deafness, and […]
