Human immunodeficiency virus type 2 (HIV-2) seroprevalence and characterization of a distinct HIV-2 genetic subtype from the natural range of simian immunodeficiency virus-infected sooty mangabeys.
The extent of zoonotic infections in rural Sierra Leone, where both feral and pet sooty mangabeys harbor divergent members of the human immunodeficiency virus type 2 (HIV-2)-sooty mangabey simian immunodeficiency virus (SIVsm) family, was tested in blood samples collected from 9,309 human subjects in 1993. Using HIV-1- and HIV-2-specific enzyme immunoassays and confirmatory Western blot analysis to test for antibodies to SIVsm-related lentiviruses, we found only nine subjects (0.096%) who tested positive for HIV: seven tested positive for HIV-1 and two tested positive for HIV-2. Compared with other rural West African communities, Sierra Leone displayed the lowest seroprevalence (0.021%) of HIV-2 infection yet reported, much lower than the previously reported seroprevalence in SIVsm-infected feral and household pet sooty mangabeys. Heteroduplex analysis demonstrated that two of the newly found HIV-1 strains belonged to subtype A, the most common HIV-1 subtype in Africa, but this is the first report of subtype A in Sierra Leone. The two HIV-2-infected individuals harbored two distinct HIV-2 strains, designated 93SL1 and 93SL2. Phylogenetic analysis indicated that HIV-2 93SL1 is a member of HIV-2 subtype A, the first strain of this HIV-2 subtype found in Sierra Leone. In contrast, HIV-2 93SL2 belongs to none of the five previously characterized HIV-2 subtypes (A to E) but is a new subtype, herein designated F, having the most divergent transmembrane sequences yet reported for HIV-2. The fact that both of the two most divergent HIV-2 subtypes known, E and F, are rare and found as single occurrences in persons from Sierra Leone may be related to the fact that this small region of West Africa also contains free-living and household pet sooty mangabeys with highly divergent variants of SIVsm. This finding provides support for the hypotheses that new HIV-2 subtypes result from independent cross-species transmission of SIVsm to the human population and that these single-occurrence transmission events had not spread widely into the population by 1993.
Chen
Z
Z
Aaron Diamond AIDS Research Center, Rockefeller University, New York, New York 10016, USA.
Luckay
A
A
Sodora
D L
DL
Telfer
P
P
Reed
P
P
Gettie
A
A
Kanu
J M
JM
Sadek
R F
RF
Yee
J
J
Ho
D D
DD
Zhang
L
L
Marx
P A
PA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D016665:Cercocebus atys / Q000821:virology*; D002648:Child; D005260:Female; D015686:Gene Products, env / Q000032:analysis; D015683:Gene Products, gag / Q000032:analysis; D005838:Genotype; D015528:HIV Seroprevalence; D015498:HIV-2 / Q000145:classification* / Q000235:genetics / Q000276:immunology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010802:Phylogeny; D015302:Simian Immunodeficiency Virus / Q000145:classification*
D015686:Gene Products, env; D015683:Gene Products, gag