Prevalences of HTLV-1 infection and associated risk determinants in an urban population in Guinea-Bissau, West Africa.
OBJECTIVE
To assess the prevalence and modes of transmission of HTLV-1 infection in an adult population in Bissau, and to evaluate possible interactions between the pattern of spread of HTLV-1 and HIV-1/HIV-2.


METHODS
Univariate and multivariate analyses were used to evaluate gender-and age-specific HTLV-1 prevalences as well as associated risk determinants in an adult population based on a serosurvey comprising 2127 individuals from 304 randomly selected houses in Bissau.


RESULTS
Using stringent Western blot criteria, the overall seroprevalence of HTLV-1 was 3.6%, 2.2% among men and 4.7% among women, respectively. One individual was seropositive to HTLV-2. The prevalence of HTLV-1, which increased with age in both genders, however more markedly among women, was >4 times higher (9.4%) among older individuals (>44 years of age) than among younger individuals (2.4%). Blood transfusion and HIV-2 seropositivity were independently associated with HTLV-1 seropositivity in men. Among women, both HIV-2 seropositivity and HIV-1 seropositivity were significant risk determinants. Having had sexual partners was associated with a fivefold increased risk among women but did not reach significance.


CONCLUSIONS
The adult population of Guinea-Bissau has a higher prevalence of HTLV-1 than reported from most other countries in West Africa. The gender-and age-specific pattern of spread of HTLV-1 closely resembles that observed for HIV-2, another retrovirus prevalent to the region. The close correlation between HTLV-1 and HIV-2 most likely reflects the shared risk factors related to sexual behavior. The implication of the high percentage of double infections in this population needs to be determined.
Larsen
O
O
Projecto de Saúde de Bandim, Bissau, Guinea-Bissau.
Andersson
S
S
da Silva
Z
Z
Hedegaard
K
K
Sandström
A
A
Nauclér
A
A
Dias
F
F
Melbye
M
M
Aaby
P
P
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015153:Blotting, Western; D016000:Cluster Analysis; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D015490:HTLV-I Infections / Q000097:blood / Q000453:epidemiology*; D015491:HTLV-II Infections / Q000097:blood / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D014505:Urban Population