Is there a focus of HTLV-II infections in the Horn of Africa?

Geographic distribution, clinical epidemiology and genetic diversity of the human oncogenic retrovirus HTLV-1 in Africa, the world's largest endemic area

The African continent is considered the largest high endemic area for the oncogenic retrovirus HTLV-1 with an estimated two to five million infected individuals. However, data on epidemiological aspects, in particular prevalence, risk factors and geographical distribution, are still very limited for many regions: on the one hand, few large-scale and representative studies have been performed and, on the other hand, many studies do not include confirmatory tests, resulting in indeterminate serological results, and a likely overestimation of HTLV-1 seroprevalence. For this review, we included the most robust studies published since 1984 on the prevalence of HTLV-1 and the two major diseases associated with this infection in people living in Africa and the Indian Ocean islands: adult T-cell leukemia (ATL) and tropical spastic paraparesis or HTLV-1-associated myelopathy (HAM/TSP). We also considered most of the book chapters and abstracts published at the 20 international conferences on HTLV and related viruses held since 1985, as well as the results of recent meta-analyses regarding the status of HTLV-1 in West and sub-Saharan Africa. Based on this bibliography, it appears that HTLV-1 distribution is very heterogeneous in Africa: The highest prevalences of HTLV-1 are reported in western, central and southern Africa, while eastern and northern Africa show lower prevalences. In highly endemic areas, the HTLV-1 prevalence in the adult population ranges from 0.3 to 3%, increases with age, and is highest among women. In rural areas of Gabon and the Democratic Republic of the Congo (DRC), HTLV-1 prevalence can reach up to 10-25% in elder women. HTLV-1-associated diseases in African patients have rarely been reported in situ on hospital wards, by local physicians. With the exception of the Republic of South Africa, DRC and Senegal, most reports on ATL and HAM/TSP in African patients have been published by European and American clinicians and involve immigrants or medical returnees to Europe (France and the UK) and the United States. There is clearly a huge underreporting of these diseases on the African continent. The genetic diversity of HTLV-1 is greatest in Africa, where six distinct genotypes (a, b, d, e, f, g) have been identified. The most frequent genotype in central Africa is genotype b. The other genotypes found in central Africa (d, e, f and g) are very rare. The vast majority of HTLV-1 strains from West and North Africa belong to genotype a, the so-called 'Cosmopolitan' genotype. These strains form five clades roughly reflecting the geographic origin of the infected individuals. We have recently shown that some of these clades are the result of recombination between a-WA and a-NA strains. Almost all sequences from southern Africa belong to Transcontinental a-genotype subgroup.

Seroprevalence of HTLV-1 and HTLV-2 amongst mothers and children in Malawi within the context of a systematic review and meta-analysis of HTLV seroprevalence in Africa

OBJECTIVES

Human T-lymphotropic virus (HTLV)-1 causes T-cell leukaemia and myelopathy. Together with HTLV-2, it is endemic in some African nations. Seroprevalence data from Malawi are scarce, with no reports on associated disease incidence. HTLV seroprevalence and type were tested in 418 healthy mothers from Malawi. In addition, we tested the sera of 534 children to investigate mother-to-child transmission. To provide context, we conducted a systematic review and meta-analysis of HTLV seroprevalence in African women and children.

METHODS

Stored samples from a previous childhood cancer and BBV study were analysed. ELISA was used for HTLV screening followed by immunoblot for confirmation and typing. Standard methods were used for the systematic review.

RESULTS

HTLV seroprevalence was 2.6% (11/418) in mothers and 2.2% (12/534) in children. Three mothers carried HTLV-1 alone, seven had HTLV-2 and one was dually infected. Three children carried HTLV-1 alone, seven had HTLV-2 and two were dually infected. Only two corresponding mothers of the 12 HTLV-positive children were HTLV positive. The systematic review included 66 studies of women and 13 of children conducted in 25 African countries. Seroprevalence of HTLV-1 varied from 0 to 17% and of HTLV-2 from 0 to 4%.

CONCLUSIONS

In contrast to findings from other studies in Africa, the seroprevalence of HTLV-2 was higher than that of HTLV-1 in Malawi and one of the highest for the African region. The lack of mother-child concordance suggests alternative sources of infection among children. Our data and analyses contribute to HTLV prevalence mapping in Africa.

Demographic and behavioral characteristics of non-sex worker females attending sexually transmitted disease clinics in Japan: a nationwide case-control study

Background

Although number of sexually transmitted infections (STIs) reported in STI surveillance increased rapidly for women in Japan during the 1990s, the sexual behavior of women potentially at risk of STI infection remains unknown.

Methods

In order to determine the demographic and behavioral characteristics of non-sex worker (SW) females attending STI clinics, female attendees (n = 145), excluding SW, from nine clinics across Japan and female controls from the general population (n = 956), both aged 18-50 years, were compared using two data sets of nationwide sexual behavior surveys conducted in 1999.

Results

Although the occupation-type and education level were unrelated to STI clinic attendance in multivariate analysis, non-SW females attending STI clinics were younger (adjusted odds ratios [AOR] = 0.94, 95%CI: 0.89, 0.99), and more likely to be unmarried (AOR = 4.11, 95% CI: 1.73, 9.77) than the controls from the general population. In the previous year, STI clinic attendees were more likely to have had multiple partnerships (AOR = 3.09, 95% CI: 1.42, 6.71) and unprotected vaginal sex with regular partners (AOR = 3.59, 95% CI: 1.49, 8.64), and tended to have had their first sexual intercourse at a younger age (AOR = 1.77, 95%CI: 0.89, 3.54) and more unprotected vaginal and/or oral sex with casual partners (AOR = 2.08, 95%CI: 0.75, 5.71). Identical sexual behavior patterns were observed between the female attendees with a current diagnosis of STI (n = 72) and those before diagnosis (n = 73) and between those with a past history of STI (n = 66) and those without (n = 79).

Conclusion

These results indicate that not only multiple partnerships or unprotected sex with casual partners, but also unprotected vaginal sex within a regular partnership is prevalent among non-SW female STI clinic attendees. The identical sexual behavior patterns observed between female attendees with a current STI diagnosis and those without, and between those attendees with a past history of STI diagnosis and those without, indicate that the result are unlikely confounded with the cases of non-STI infection. This sexual behavior pattern may be predictive of STI infection among young Japanese women and could have contributed to the STI epidemic in women in Japan during the 1990s.

'Searching for a "generalized social agent" to predict Namibians' intentions to prevent sexual transmission of HIV

Debate surrounds the definition, measurement and utility of subjective norms (theory of reasoned action, Fishbein & Ajzen, 1975; Ajzen & Fishbein, 1980). Scholars propose alternative concepts including descriptive norms and injunctive norms (Cialdini et al., 1990), enabling factors and social embeddedness (e.g. Barrera, 1986), and betweenness to others in a network (Wasserman & Faust, 1994) to explain social influences on willingness to perform a behaviour. This study explores the relative utility and comparability of different social concepts in understanding Namibians' intentions (n=1200) to abstain from sex or to be faithful to one sexual partner. Neither subjective norms nor the five other concepts consistently predict either intentions, although they account for 21% of variance in intentions to abstain and 24% of intentions to have one sexual partner in one region. Conflicting relationships between injunctive and subjective norms exist; stigma surrounding HIV prevention provides some explanation. Campaigns designed to alter norms may benefit from altering stigma simultaneously.

The magnitude of key HIV prevention challenges in the United States: implications for a new national HIV prevention plan

The Centers for Disease Control and Prevention has undertaken an advisory process to update its national HIV prevention plan. We offer observations on the magnitude of HIV prevention challenges in the United States and reflect on how these challenges might influence the structure of a new HIV prevention plan. We recommend a plan structure that (1) is based on fundamental principles of prevention, (2) enables accountability and mid-course correction, and (3) if achieved, would result in historic changes in the US HIV epidemic. The recommended plan structure would differentially prioritize serostatus determination and prevention and care interventions for people living with HIV while retaining goals directed at high-risk HIV-negative and general population members.

HIV Infection and AIDS in the Deep South

We examine epidemiological and demographic data documenting the HIV/AIDS epidemic in the Deep South region of the United States. These data document substantial increases in AIDS cases in the Deep South from 2000 to 2003. In contrast, other US regions are experiencing stable rates or small increases in new AIDS cases. Furthermore, the AIDS epidemic in the Deep South is more concentrated than in other regions among African Americans, women, and rural residents. The Deep South also has some of the highest levels of poverty and uninsured individuals, factors that complicate the prevention and treatment of HIV infection. Further research is needed to determine the cause of the disproportionate rise in AIDS incidence and to develop effective means of preventing HIV infection and providing care of those infected in this region.

Estimating the effectiveness and efficiency of US HIV prevention efforts using scenario and cost-effectiveness analysis

Scenario and cost-effectiveness analyses were used to estimate the effectiveness and efficiency of HIV prevention activities in the USA (1978-2000). Under four conservative scenarios on the course of HIV epidemic that might have occurred had there been no prevention efforts. we estimate that prevention activities averted 204,000-1,585,000 infections at a cost of between 49,700 US dollars and 6400 US dollars per infection prevented (less than the medical costs of treating a case of HIV disease).

HIV-related behaviors and perceptions among adults in 25 states: 1997 Behavioral Risk Factor Surveillance System

OBJECTIVES

To assess the level of HIV-related risk behavior among the general US adult population, we analyzed data from the first sexual behavior questions available for states to use with the Behavioral Risk Factor Surveillance System.

METHODS

The Behavioral Risk Factor Surveillance System is a state-specific, population-based, random telephone survey. In 1997, 25 states collected sexual behavior data. Annual prevalence estimates for selected behaviors were calculated and examined by sociodemographic characteristics. The correlation between actual and perceived HIV risk also was determined.

RESULTS

Most (77.1%) of the respondents reported just 1 sexual partner in the past year; 26.0% reported using a condom at last intercourse. Males, persons who were younger, and Blacks were more likely to report 2 or more partners but also more likely to report using a condom at last intercourse. Only 4.1% of the respondents reported a risk factor for HIV infection; 7.7% reported that they were at medium or high risk for HIV. Actual and perceived HIV risk were positively associated.

CONCLUSIONS

Most US adults do not engage in HIV-related risk behavior; those that do are more likely to report protective behavior.

Crack smokers' intention to use condoms with loved partners: intervention development using the theory of reasoned action, condom beliefs, and processes of change

Prevalence rates of HIV infection acquired through heterosexual contacts have risen steadily since 1982. Crack cocaine smokers are at particular risk of HIV infection due to heterosexual exposure. HIV risk reduction interventions seeking to increase condom use among drug users have met with minimal success, and there is a need for interventions to be strongly grounded in psychosocial models of behaviour change. This study presents the results of an investigation of predictors of intention to use condoms and related therapy processes among heterosexual drug users. Data were analyzed from 586 crack smokers recruited in Washington, DC, Miami, Florida, and Collier County, Florida who reported having both primary and casual sex partners. Participants responded to items derived from the theory of reasoned action, the theory of planned behaviour and the transtheoretical model of change. Condom use beliefs and therapy processes used to initiate and maintain condom use were assessed. Outcome expectancies and normative beliefs were the strongest predictors of intention to use condoms with a primary sexual partner. In turn, beliefs that condoms inhibit sexual romance and decrease sexual pleasure strongly predicted outcome expectancies. Therapy processes found to be associated with these constructs included: self-liberation, counter conditioning and stimulus control/reinforcement. Results suggest that HIV risk reduction interventions using a group format and targeting condom beliefs related to sexual romance and pleasure will decrease negative outcome expectancies about condom use. Also, reinforcing attempts to use condoms with intimate partners should increase positive outcome expectancies and intention to initiate or maintain condoms with a primary sexual partner.

The Serostatus Approach to Fighting the HIV Epidemic: prevention strategies for infected individuals

In the United States, HIV prevention programs have historically tailored activities for specific groups primarily on the basis of behavioral risk factors and demographic characteristics. Through the Serostatus Approach to Fighting the Epidemic (SAFE), the Centers for Disease Control and Prevention is now expanding prevention programs, especially for individuals with HIV, to reduce the risk of transmission as a supplement to current programs that primarily focus on reducing the risk of acquisition of the virus. For individuals with HIV, SAFE comprises action steps that focus on diagnosing all HIV-infected persons, linking them to appropriate high-quality care and prevention services, helping them adhere to treatment regimens, and supporting them in adopting and sustaining HIV risk reduction behavior. SAFE couple a traditional infectious disease control focus on the infected person with behavioral interventions that have been standard for HIV prevention programs.