Simian immunodeficiency virus

The simian immunodeficiency virus ( SIV, Eng. Simian immunodeficiency virus, simian = monkey, ape -like) is a retrovirus and is considered the source virus to the human immunodeficiency virus HIV. SIV describes a whole group of different viruses that were isolated from the blood or organ material of various species of monkeys. The result is probably before the last glacial 32000-75000 years ago. In the 1980s, these viruses were referred to as simian T- lymphotropic virus 3 ( STLV -III).

Features

The SIB is an enveloped single ( ) strand RNA virus, (ss ( ) RNA ), the genetic information present as RNA, but when the DNA is incorporated into the genome of the host cell. Genetically, it is closely related to HIV.

Subclasses of the SIV

From SIV, there are three subclasses:

• SIVcpz ( chimpanzee from the chimpanzee Pan troglodytes). This virus is mainly found in chimpanzees in captivity. SIVcpz is closely related to the HIV -1 virus from him are derived from HIV -1 M / N / O. Through studies of gorillas in Cameroon infected animals antibodies have been detected in the feces SIV, as they are also people who have been infected with HIV-1 group O.

• SIVsm or SIVsmm ( sooty mangabey monkey of which Rußmangabe Cercocebus atys, a Mangabenart ). Also, this virus can be found in animals in captivity and in the wild.

• SIVmac (from rhesus macaques ). SIVmac is closely related to the discovered 1986 HIV-2. HIV-2 is less common and less virulent than HIV-1.

These subclasses are each further subdivided.

Occurrence

In connection with the occurrence of AIDS and the isolation of the disease -causing virus was subsequently in different African monkey species in the wild, such as vervets and mangabeys, later also found in chimpanzees and gorillas SIV. The isolates from chimpanzees exhibit in all SIVs to the highest degree of relationship with HIV.

The first SIV isolates were found in rhesus monkeys that were kept in captivity in zoos or primate centers and had died from AIDS - related illnesses. Rhesus monkeys and related species are native to Asia, and their populations are not durchseucht with SIV. Only when they are kept in unnatural proximity with African apes, for example, in common or adjacent enclosures, SIV can be transmitted by biting of the infected to it. For a long time it was assumed that none of the African monkeys with "his virus" is sick, Asian but very comfortable. Investigations in the Gombe National Park in Tanzania, however, could be demonstrated that SIVcpz can ill chimpanzees. In ten years of study SIV infection and a 10 to 16 times higher risk of death compared to non-infected animals was determined by highly sensitive SIV testing of feces and urine in 17 of 94 known animals. In addition, it has been found in tissue samples from three dead, SIV -positive chimpanzees that the number of CD4 T cells was extremely low as in people suffering from Aids in the late phase.

With regard to the transmission of immunodeficiency viruses to humans, it is believed that a chimpanzee SIV was born decades ago in the human population - with the known consequences. According to the current hypothesis regarding the transmission of the virus to humans, it is believed that hunters who have hunted and eaten monkeys were infected with the virus for the first time. Another theory assumes that in 1959 contaminated cell cultures of monkey found use in the preparation and testing of the first polio vaccines, which were then tested in the Congo region, with the virus. However, an analysis of the mutations, with 95 percent probability of the origin of the strain HIV -1 can be dated before the year 1930. In February 2000, a sample of the distributed oral vaccines has been found and studied. It showed no trace of HIV or SIV.