Molecular epidemiology of HIV type 1 in Chile: differential geographic and transmission route distribution of B and F subtypes.
We examined the genetic makeup of 221 HIV-1 strains from Chilean persons living with HIV/AIDS by HMA and DNA sequencing of the env gene: 143 cases were infected by sexual contact with an already-infected partner, 76 were infected by mother-to-child transmission, and 2 were transfusion related. We found env HIV-1 subtype B in 202 cases (91.4%) and subtype F in 19 cases (8.6%). Subtype B strains were found throughout the country whereas subtype F viruses were predominantly found in cases from the metropolitan/central to the northern regions of Chile (p < 0.01). Chilean F subtypes clustered in two different groups: viruses from the central region clustered with F subtypes from Argentina, Uruguay, and Brazil, and viruses from the northern region, which independently segregated from other South American and European F strains. All of the 59 men having sex with men (MSM) were infected with B subtype strains whereas 7 (9.2%) and 12 (15.8%), respectively, of heterosexually infected females and children were infected with F subtype strains (p < 0.01). It appears that F subtype strains have been introduced into Chile by separate heterosexual transmission events from other nearby countries in the Southern Cone whereas B subtype strains have continued to persist predominantly among MSM.
Rios
M
M
National Reference Center of Retroviruses, Public Health Institute of Chile, Santiago, Chile.
Fernandez
J
J
Jaramillo
P
P
Paredes
V
V
Sanchez
J L
JL
Laguna-Torres
V A
VA
Carr
J K
JK
Ramirez
E
E
D000328:Adult; D001803:Blood Transfusion; D002648:Child; D002677:Chile / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D017720:Molecular Epidemiology; D010802:Phylogeny; D012725:Sexual Behavior