Ethnic composition, age and sex, together with location and standard of housing as determinants of HTLV-I infection in an urban Trinidadian community

The presence of antibody to human T-cell leukaemia virus (HTLV-I) has been assessed in 2,143 men and women who represent 83 percent of all adults aged 35 to 69 years resident in a defined urban community in Trinidad. Individuals of African descent had a higher sero-positivity rate (7.0 percent) than those originating from India (1.4 percent), Europe (0 percent) or of mixed descent (2.7 percent). Women were infected more frequently than men, and the prevalence of infection increased with age in both sexes. Sero-positivity rates were significantly increased in adults who lived in housing of poor quality (p less than 0.001) or close to water courses (p less than 0.025). These data and others raise the possibility that one route of HTLV-I transmission may be via insect vectors under particular domestic circumstances.(AU)

Clustering of human T lymphotropic virus type 1 seropositive in Montserrat, West Indies: evidence for an environmental factor in transmission of the virus

A community survey of human T cell lymphotropic virus type I (HTLV-I) in Montserrat, West Indies, identified 22 instances in which 2 HTLV-I-seropositive adults lived within 60 m of each other (close pairs), compared with 7.8 expected (P<.001). Five of these close pairs were mother offspring or husband-wife. The remaining 17 pairs were of unrelated members in separate households. The percentages of male-female (41 percent), female-female (41 percent), and male-male (18 percent) types in these 17 pairs were similar to those among the 1377 similarly defined pairs in which neither or only 1 member was seropositive, affording no support for extramarital heterosexual activity as an explanation for the clustering observed. Thus, the demography of HTLV-I was not accounted for completely by sexual and mother-to-offspring tranmission. The predominace of clustering of unrelated HTLV-I-seropositive individuals in locations with high mosquito infestation raised the possibility of sporadic transmission of HTLV-I by hematophagous insects (AU)

HTLV-1 and dengue seropositivity in Montserrat - abstract

Over 80 percent of the adult population of three villages in Montserrat donated blood samples for screening for HTLV-I and dengue antibodies. Twenty-five (7.2 percent) of the 349 samples tested were positive for HTLV-I antibodies and 17 of them live in 4 clusters of neighbouring households which was statistically significant. This clustering was not primarily due to viral or mother-to-child transmission but was the result of related and unrelated seropositive individuals living near to each other far more frequently than by chance alone. Two hundred and two (61 percent) of 331 samples tested were seropositive for dengue. Dengue seropositivity prevalence rates increased markedly with age and showed a strong difference in prevalence by altitude. This high prevalence of dengue seropositivity was surprising since no epidemics of dengue fever were reported in Montserrat. There is no evidence to support the hypothesis that the same insect vectors have a role in both dengue and HTLV-I transmission. However, the clustering observed, the inverse relation between HTLV-I sero prevalence and altitude and the failure of HTLV-I to establish itself in temperate climates, justify the need for further studies (AU)

The human type-C retrovirus, in Blacks from the Caribbean region, and relationship to adult T-cell leukemia/lymphoma

Type-C RNA tumour viruses have been implicated in the etiology of naturally occurring leukemias and lymphomas of animals. Human T-cell leukimia/lymphoma virus (HTLV) is the first human virus of this class consistently identified in association with a specific type of human leukemia/lymphoma. The isolation of HTLV was made possible by the ability to grow mature T-cell in tissue culture usually with T-cell growth factor (TCGF). We now report a cluster usually with T-cell leukemia/lymphoma among Blacks from the Caribbean in which all eight cases are positive for HLV virus and/or antibody. These patients have diseases that appears indistinguisable from Japanese adult T-cell leukemia/lymphoma which, as we have also reported, is associated with HTLV in over 90 percent of cases. The finding of HTLV antibodies in some of the normal population in the Caribbean and Japan, and the clustering of a specific form of T-cell leukemia/lyphoma in these virus-endemic areas, suggest that HTLV infection may be associated with the occurrence of a distinctive clinico-pathologic entity (Summary)