Scimex: Two versions of the HIV virus may have been transmitted from gorillas to
humans, suggests a study that looked at the equivalent virus, SIV, in
gorilla populations across Africa. Of the four known HIV-1 groups, two
have been linked to chimpanzees but the remaining two have been
difficult to trace. Scientists have now identified two types of SIV in
western lowland gorillas in Cameroon that show striking similarity to
HIV-1 - indicating that some strains of the AIDS-causing virus
originated in gorillas, not chimpanzees.
A survey of simian immunodeficiency virus (SIV) infection in African
gorillas reveals that two of the four known HIV-1 lineages may have been
transmitted from western lowland gorillas to humans, according to a
study.
The virus that causes AIDS in humans, HIV-1, has crossed
species boundaries to infect humans at least four times, resulting in
four distinct HIV-1 lineages, termed groups M, N, O, and P. Previous
findings show that groups M and N originated in geographically distinct
chimpanzee communities in Cameroon, but the origins of groups O and P
have remained uncertain.
Martine Peeters, Beatrice Hahn, and
colleagues screened fecal samples from western lowland gorillas, eastern
lowland gorillas, and mountain gorillas in Cameroon, Gabon, the
Democratic Republic of Congo, and Uganda for the presence of SIVs that
are thought to be the precursors of HIV-1.
The authors detected
SIV in four groups of western lowland gorillas in Cameroon. Viral
sequencing revealed a high degree of genetic diversity among the
different gorilla SIV samples, but all derived from a single chimpanzee
SIV strain.
Two of the gorilla SIV lineages showed striking
similarity to HIV-1 groups O and P, indicating that the two groups
originated in gorillas, according to the authors.