Heterosexual transmission of human immunodeficiency virus type 1 subtype C in southern Brazil.
BACKGROUND
Human immunodeficiency virus type 1 (HIV-1) subtype B predominates in Brazil, but in the southern region subtype C is the most frequent, followed by subtypes B, F1 and recombinant forms. In southern Brazil, these subtypes co-circulate in subjects with homogeneous demographic and clinical features, enabling a better understanding of the role of HIV-1 subtypes on the characteristics of infection.


OBJECTIVE
To evaluate the prevalence of different HIV-1 subtypes in subjects with recent diagnosis for HIV infection in the extreme south of Brazil, and to study their association with demographic, behavioral, clinical and laboratorial characteristics.


METHODS
We have determined the genetic sequence of viral protease and reverse transcriptase (polymerase, connection and RNase H domains) isolated from studied subjects. Viral subtype was inferred by comparison with reference HIV sequences, and recombination was determined with Simplot analysis. The association of HIV-1 subtypes with studied characteristics was evaluated by chi-square, Fisher's exact, Student's t and Kruskal-Wallis tests.


RESULTS
Two hundred and forty-five HIV isolates were molecularly characterized, and the association with variables was studied for 233 (95.1%) patients. Of those, 46.8% followed AIDS defining criteria. HIV-1C was responsible for 56.3% of infections, and was associated with heterosexual transmission (p=0.001) and with higher CD4(+) T-cell counts (p=0.02).


CONCLUSIONS
The molecular epidemiology of HIV-1 in the southernmost Brazil is currently steady with predominance of HIV-1C. This is the first study showing a robust association of the infection by this subtype and heterosexual transmission in the state of Rio Grande do Sul, Brazil.
Faculdade de Medicina, Universidade Federal de Rio Grande, Rio Grande, Brazil.
Jussara
J
Silveira
André F
AF
Santos
Ana M B
AM
Martínez
Lívia R
LR
Góes
Raul
R
Mendoza-Sassi
Claudia P
CP
Muniz
Unaí
U
Tupinambás
Marcelo A
MA
Soares
Dirceu B
DB
Greco
D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D005838:Genotype; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D016333:HIV Protease / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D020010:Heterosexuality; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D055815:Young Adult
C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; D016333:HIV Protease