HIV-1 diversity and prevalence differ between urban and rural areas in the Mbeya region of Tanzania

OBJECTIVE: To characterize HIV-1 strains in a potential vaccine trial cohort (CODE) in the Mbeya region of southwest Tanzania. DESIGN: Study volunteers (n = 3096) were recruited from urban areas in Mbeya Town, using two different recruitment strategies, and in a nearby rural village. METHODS: Cryopreserved plasma from 507 HIV-1 prevalent cases was the source of viral RNA for HIV-1 genotyping by the Multi-region Hybridization Assay, the MHA(acd), and selected strains were confirmed by complete genome sequencing. RESULTS: The overall HIV-1 prevalence was 16.6% [95% confidence interval (CI), 15.3-17.9] within the cohort. HIV-1 prevalence was higher among women, and in urban areas. Recruitment through advertisement targeted a high-risk urban male population for HIV-1 infection [adjusted odds ratio (adj. OR), 1.68; 95% CI, 1.13-2.51] when compared with men recruited door-to-door. The complexity of the HIV-1 epidemic was also higher in urban areas evidenced by the high-risk of HIV-1 infection with a recombinant strain (adj. OR, 2.69; 95% CI, 1.08-6.69) and HIV-1 dual infection (adj. OR, 5.16; 95% CI, 1.07-24.9), mainly driven by urban men recruited through advertisement. CONCLUSIONS: Overall the urban epidemic was more genetically complex, with higher prevalence and more recombinants and dual infections. Vaccine trials in Mbeya region can assess a complex HIV-1 population dynamic and determine vaccine efficacy in relationship to the genetic diversity of HIV-1 strains that challenge vaccines.     

Household survey in two provinces in Viet Nam estimates HIV prevalence in an urban and a rural population

A household-based population study interviewed 2,553 women and 1,984 men aged 15-49 years in urban (Ho Chi Minh City) and rural (Thai Binh) provinces in Viet Nam between July and August 2005. The survey response rate was high--approximately 97% of households and 93% of adults overall, with a >92% acceptance of HIV testing among eligible adults. The unadjusted estimated population HIV prevalence was 0.3% (confidence interval [CI]: 0.1-0.6%) in Thai Binh and 0.7% (CI: 0.3-1.3) in Ho Chi Minh City (HCMC), compared with the national estimates and projections of 0.352% and 1.250%, respectively, for 2005. The ratio of male-to-female prevalence was 10.5:1 in Thai Binh and 1.3:1 in HCMC. A low level of men reported purchasing sex in the last 12 months (2.4%) and there were low self-reports of sexually transmitted infections in all adults (5%). A correct knowledge of HIV/AIDS prevention methods was high in both provinces (83%), although only 24.8% of women knew of the use of antiretroviral therapy to prevent vertical transmission of HIV. The observed population prevalence was consistent with recent projections in Thai Binh, although lower than expected in HCMC, indicating the substantial downward revisions of projected population HIV prevalence may need to be extended. The unequal sex prevalence ratio is consistent with the projected trends of increasing male-to-female sexual transmission in urban areas. The results and experience of this study will inform future population based surveys in Viet Nam and the broader Asian region.     

Prevalence of HIV infection in psychiatric patients attending a general hospital in Tamil Nadu,south India

An anonymous, unlinked study was conducted to detect antibodies to HIV-1 or HIV-2 infections in 1,160 consecutive, newly registered, adult psychiatric outpatients at a general hospital in South India to determine whether psychiatric patients presenting to general hospitals are a population at high risk for HIV infection and should be routinely screened. The seroprevalence of HIV infection (12/1160; 1.03%; 95% CI = 0.4-1.6%) did not approximate rates expected of a high-risk group compared to the national (0.7%) or regional community (1.8%) prevalence. It did not differ significantly from HIV seroprevalence in non-psychiatric patients (233/35450; 0.7%; 95% CI = 0.57-0.74%) who were systematically screened (relative risk = 1.57; 95% CI = 0.88-2.80) during the same period, but was greater than the seroprevalence in healthy blood donors (0.5%; p = 0.02; relative risk = 2.15 95% CI = 1.17-3.95). Non-psychiatric patients were also more likely to be HIV infected than blood donors (p = 0.02; relative risk = 1.37; 95% CI = 1.05-1.78). These findings have implications for HIV testing policies among psychiatric and non-psychiatric patients presenting to general hospitals in India.     

Detection of Acute and Established HIV Infections in Sexually Transmitted Disease Clinics in Guangxi, China: Implications for Screening and Prevention of HIV Infection

BACKGROUND: Human immunodeficiency virus (HIV) has spread throughout China and to some degree has penetrated the general heterosexual population in some regions.METHODS: A cross-sectional survey of 11,461 sexually transmitted disease (STD) clinic attendees in 8 cities in Guangxi, China, was conducted for syphilis and for acute and established HIV infections. RESULTS: The prevalence of acute and established HIV infections was 1.2% among the participants. Five acute (preseroconversion) HIV infections were detected. Multivariate analysis showed that HIV infection was independently related to unmarried status (odds ratio [OR], 1.73 [95% confidence interval {CI}, 1.00-2.99), less education (OR for less than primary school, 4.21 [90% CI, 1.21-14.58]), residence in city A (OR, 11.48 [95% CI, 2.05-64.31]) or city B (OR, 7.93 [95% CI, 1.75-35.91]), working in the entertainment industry (OR, 3.98 [95% CI, 1.14-13.88]), injection drug use (OR, 25.09 [95% CI, 10.43-60.39]), no condom use during most recent sexual intercourse (OR, 4.97 [95% CI, 1.38-17.88]), and syphilitic infection (OR, 1.91 [95% CI, 1.03-3.56]). CONCLUSIONS: HIV prevalence in STD clinics is significantly greater than that in the general population, and subjects were identified who would be missed by conventional surveillance. China's nationwide system of public STD clinics, which reach down to the township level, should be used for HIV control programs.     

Marked HIV prevalence declines in higher educated young people: evidence from population-based surveys (1995-2003) in Zambia

OBJECTIVES: Higher educational attainment has been associated with a greater risk of HIV infection in sub-Saharan Africa. We investigated change over time in HIV prevalence by educational attainment in the general population. METHODS: The data stem from serial population-based HIV surveys conducted in selected urban and rural communities in 1995 (n = 2989), 1999 (n = 3506) and 2003 (n = 4442). Analyses were stratified by residence, sex and age-group. Logistic regression was used to estimate age-adjusted odds ratio of HIV between low (< or = 4 school years) and higher education (> or = 8 years) for the rural population and between low (< or = 7 school years) and higher education (> or = 11 years) for the urban population. RESULTS: There was a universal shift towards reduced risk of HIV infection in groups with higher than lower education in both sexes among urban young people [odds ratio (OR), 0.20; 95% confidence interval (CI), 0.05-0.73] in men and (OR, 0.33; 95% CI, 0.15-0.72) in women. A similar pattern was observed in rural young men (OR, 0.17; 95% CI, 0.05-0.59) but was less prominent and not statistically significant in rural women. In age 25-49 years, higher educated urban men had reduced risk in 2003 (OR, 0.43; 95%CI, 0.26-0.72) but this was less prominent in women. CONCLUSIONS: The findings suggested a shift in the association between educational attainment and HIV infection between 1995 and 2003. The most convincing sign was the risk reduction among more educated younger groups where most infections can be assumed to be recent. The changes in older groups are probably largely influenced by differential mortality rates. The stable risk among groups with lower education might also indicate limitations in past preventive efforts.     

Regional differences in HIV trends in The Gambia: results from sentinel surveillance among pregnant women

OBJECTIVE: To monitor HIV-1 and HIV-2 trends in The Gambia, West Africa. METHODS: In 1993-1995 a nationwide survey among 29 670 pregnant women attending eight antenatal clinics estimated the seroprevalence of HIV-1 at 0.6%, and of HIV-2 at 1.1%. Five years later, sentinel surveillance in pregnant women was established, using unlinked anonymous testing in four clinics. A dried blood spot on filter paper was obtained and tested for HIV antibodies. RESULTS: Between May 2000 and August 2001, 8054 analysable samples were collected at four sites. The prevalence of HIV-1 rose sharply in one rural area from 0.6 to 3.0% (P < 0.0001), but the increase was small and non-significant in two other rural sites and in the urban site. The prevalence of HIV-2 did not change significantly at any of the sites. The overall prevalence of HIV-1 was 1.0% [95% confidence interval (CI) 0.8-1.3%], and of HIV-2 0.8% (CI 0.6-1.0%). Site, nationality and higher age were significantly associated with HIV-1 infection, and higher parity and site were significantly associated with HIV-2 infection. CONCLUSION: Fifteen years after the first case of HIV-1 was described in The Gambia, the epidemic is still at a low level. There is heterogeneity within the country, with one rural area experiencing a fivefold increase in 6 years. The prevalence of HIV-2 in The Gambia is stable.     

Trend in HIV-1 prevalence in an antenatal clinic in North Uganda and adjusted rates for the general female population

OBJECTIVES: To estimate HIV-1 prevalence among women attending an antenatal clinic in the Gulu District (North Uganda) and, based on these data, among the district's female population. METHODS: Anonymous HIV-1 screening was performed for 8555 antenatal clinic attendees aged 15-39 years in the period 1993-1997. The results were used to estimate the prevalence among the district's female population, accounting for differences in fertility rates by HIV-1 serostatus. RESULTS: Among antenatal clinic attendees, HIV-1 prevalence showed a significant linear decrease (P < 0.001), from 26.0% in 1993 [95% confidence Interval (CI), 23.2-29.0%] to 16.1% in 1997 (95% CI, 14.8-17.5%). This decrease was mostly due to a marked decrease until 1995 (14.3%; 95% Cl, 12.7-16.0%) and was more pronounced among women aged under 30 years (P < 0.001), from both urban and rural areas (P < 0.001). The risk of being infected was higher among women from urban areas (Gulu Municipality), both over the entire period (adjusted prevalence proportion ratio = 1.54; 95% CI, 1.40-1.68) and by individual year. The estimated prevalence for the 15-39-year-old female population, standardized by age and area of residence, decreased from 25.4% in 1993-1994 to 17.8% in 1996-1997; these rates were 1.22 and 1.28 times higher, respectively, than those among antenatal clinic attendees. CONCLUSIONS: The trend of decrease among young women, for whom changes in HIV-1 prevalence more closely reflect incidence, could be partially due to a reduction in risk behaviour and a consequent decreasing incidence. Differences in fertility rates by HIV-1 serostatus should be addressed when using antenatal clinic data to estimate prevalence among the general female population.     

Young people's sexual health in South Africa: HIV prevalence and sexual behaviors from a nationally representative household survey

OBJECTIVES: To determine the prevalence of HIV infection, HIV risk factors, and exposure to national HIV prevention programs, and to identify factors associated with HIV infection among South African youth, aged 15-24 years. DESIGN: A cross-sectional, nationally representative, household survey. METHODS: From March to August 2003 we conducted a national survey of HIV prevalence and sexual behavior among 11 904 15-24 year olds. Multivariable models for HIV infection were restricted to sexually experienced youth. RESULTS: Young women were significantly more likely to be infected with HIV in comparison with young men (15.5 versus 4.8%). Among men, a history of genital ulcers in the past 12 months was associated with HIV infection [adjusted odds ratio (AOR), 1.91; 95% confidence interval (CI), 1.04-3.49) whereas among women a history of unusual vaginal discharge in the past 12 months was associated with HIV infection (AOR, 1.75; 95% CI, 1.26-2.44). Young women with older partners were also at increased risk of HIV infection. Among both men and women, increasing partner numbers and inconsistent condom use were significantly associated with HIV infection. Males and females who reported participation in at least one loveLife program were less likely to be infected with HIV (AOR, 0.60; 95% CI, 0.40-0.89; AOR, 0.61; 95% CI, 0.43-0.85, respectively). CONCLUSION: This survey confirms the high HIV prevalence among young people in South Africa and, in particular, young women's disproportionate risk. Programs for youth must continue to promote partner reduction, consistent condom use and prompt treatment for sexually transmitted infections while also addressing contextual factors that make it difficult for them to implement behavior change.     

Dual infections with HIV-1, HIV-2 and HTLV-I are more common in older women than in men in Guinea-Bissau

OBJECTIVES: To investigate the association between the three human retroviruses, HIV-1, HIV-2 and HTLV-I. DESIGN: Community-based follow-up studies of retrovirus infections in two cohorts. METHODS: A total of 2057 individuals aged 35 years and over were eligible for inclusion. Participants were interviewed and had a blood sample drawn. Samples were analysed for HIV-1, HIV-2 and HTLV infections. Uni- and multivariate analyses that included behavioural and socio-economic factors were performed using logistic regression and Poisson regression models. RESULTS: A total of 1686 individuals participated with a blood sample in the HIV prevalence analyses and 1581 individuals participated in the HTLV-I prevalence analyses. The overall prevalence was 2.1% for HIV-1, 13.5% for HIV-2 and 7.1% for HTLV-I. Comparing the < 45 year age group with 45+ year age groups, the female : male (F : M) prevalence ratio increased with age for all three retroviruses. Dual infections were more common in women than in men. Assuming independent distribution of the viruses, the observed prevalence of dual infections in women was significantly higher than expected, while the prevalence was not increased in men. The prevalence of dual infections increased with age in women, the odds ratio (OR) being 3.4 [95% confidence interval (CI), 1.0-11.3] for any combination of dual infection, while the prevalence decreased with age in men (OR, 0.3; 95% CI, 0.1-2.0) (test of interaction, P = 0.033). Control for behavioural factors did not modify these patterns. CONCLUSIONS: The pattern of increased prevalence among older women could have public health implications; women of older age groups should be regarded as a potential vulnerable group and included in HIV/AIDS prevention programmes.     

我国部分农村地区40岁以上女性慢性阻塞性肺疾病危险因素分析

目的探究我国农村女性慢性阻塞性肺疾病（COPD）的患病危险因素。方法在全国COPD流行病调查的基础上,选取农村地区40岁以上的女性为分析对象。全国COPD流行病调查采用多阶段分层整群随机抽样方法,进行问卷和肺功能检测;以吸入支气管扩张剂后第1秒钟用力呼气容积（FEV1）／用力肺活量（FVC）〈0．70作为诊断COPD的标准,并排除其他不完全可逆气流受限疾病。结果农村女性总体患病率为5．4％,危险因素暴露率、COPD患病率存在地区差异（P值均小于0.05）;多因素分析显示,COPD的主要危险因素有：家族呼吸疾病史（OR=2．46,95％CI=1．86-3．26）、儿童时期经常咳嗽（经常咳嗽与从无咳嗽比较,OR=3．93,95％CI=2．02-7．63）、年龄大（70岁以上与40-49岁比较,OR=8．98,95％CI=5．90～13．67）、低体重指数（BMI）（低BMI与正常BMI比较,OR=2．20,95％CI=1．47-3．29）、吸烟（OR=1．68,95％CI=1．20-2．35）、有职业粉尘暴露（主要为谷尘暴露,OR=1．45,95％CI=1．07-1．96）、厨房无通风设备（OR=1．47,95％CI=1．06-2．03）和文化程度低（OR=2．19,95％CI=1．38-3．46）。结论中国农村女性COPD的危险因素是多方面的,应重视其防治。     

The impact of HIV infection on adult mortality in some communities in Zambia: a cohort study

Objective  To examine the contribution of human immunodeficiency virus (HIV) to adult death rates between 1995/1996 and 1998/1999 in some urban and rural populations in Zambia.
Method  A cohort of 2592 out of 3013 adults aged 15–49 years enrolled in a baseline survey in 1995/1996 in areas of Chelston Township (HIV prevalence 26.2%) and Kapiri Mposhi district (HIV prevalence 15.6%) were followed up in 1998/1999. Person years of observation (PYO) were calculated for those known to have been alive, dead and migrated between the surveys. Fixed covariates Cox proportional hazard models were fitted to assess survival prospects.
Results  Death rates per 1000 PYO in the rural cohort were 38.1 among those with HIV, 4.8 among those without HIV and 9.8 for all; the population attributable fraction of deaths among those with HIV was 52.3%. Respective estimates in the urban cohort were 53.8, 4.6, 17.2 and 73.6%. The hazard rate (HR) ratio of death for persons infected with HIV was 8.7 times [HR 8.65; 95% confidence interval (CI) 5.28–14.15] higher than for the uninfected after adjusting for age, area of residence, marital status, self-rated health and years spent on education. HR among those who rated their health good/excellent was 40% less, i.e. HR 0.60 (95% CI: 0.40–0.91) than those who rated it to be poor/fair.
Conclusions  HIV infection was the most important factor accounting for adult deaths in the communities.     

HIV prevalence among injection drug users in rural Guangxi China

AIMS: To determine the HIV-1 seroprevalence, risk behaviors and demographic characteristics associated with HIV-1 infection among injection drug users (IDU) in rural Guangxi, China. DESIGN AND SETTING: Between July and November 2002, 702 IDU were screened for HIV-1 antibody through community outreach in rural Guangxi, China for enrollment in an HIV sero-incidence study. PARTICIPANTS: A total of 702 active high-risk IDU were screened. High-risk injection was defined as anyone who reported injecting drugs at least three times per week in the last month or injected drugs with shared equipment on at least three occasions in the last 3 months. MEASUREMENTS: HIV-1 antibody testing with confirmation by Western blot was performed on all subjects. Demographic and risk assessment survey data were collected at screening from everyone whose baseline HIV antibody status was known. FINDINGS: HIV-1 antibody prevalence among 702 IDU at baseline was 25% with a median age of 26.7 years (18.2-43.2). Based on a multivariate logistic regression model using risk factors identified in univariate analyses, the following risk factors were associated significantly with an increase in risk for HIV seropositivity: age > 26 years (OR 1.50; 95% CI 1.04, 2.17), sharing of rinse water (OR = 1.24; 95% CI 1.09, 1.40), not having sex in the last 6 months (OR = 1.62; 95% CI 1.08, 2.43). CONCLUSIONS: HIV infection among IDU in Guangxi, one of China's major HIV epidemic regions, is high and the infection occurs predominantly among older IDU males who share rinse water.     

The role of in-migrants in the increasing rural HIV-1 epidemic: results from a village population survey in the Kilimanjaro region of Tanzania.

OBJECTIVE: To investigate the magnitude of rural in-migration and the role of in-migrants in the observed increase in HIV-1 prevalence in rural Kilimanjaro, Tanzania. METHODS: A cross-sectional study involving the adult population aged 15-44 years residing in a rural village was conducted from March to May of 2005. Participants were interviewed regarding their risk behaviors and gave blood for HIV-1 and syphilis testing. RESULTS: Overall, the response rate was 73.0% (1528/2093). A total of 699 (48.1%) participants reported having in-migrated to the village at some point during their life. The prevalences of HIV-1 infection were 1.8%, 2.3%, and 3.7% among non-in-migrant, long-term in-migrant, and recent in-migrant men, respectively (p(trend)<0.001). The corresponding prevalences among women were 9.2%, 11.5%, and 14.5%, respectively (p(trend)=0.048). The odds of HIV-1 infection were higher among recent in-migrants as compared to non-in-migrants (men: adjusted odds ratio (AOR) 2.4, 95% CI 1.8-6.6; women: AOR 2.3, 95% CI 1.1-5.0). Risk behaviors were inversely related to years since in-migration for both sexes. CONCLUSIONS: The results suggest that rural in-migration is common for both men and women. In-migrants were at higher risk for HIV-1 infection and contributed significantly to increased rural HIV-1 prevalence. More studies to examine the rate and broader causes of rural in-migration in similar communities are called for. These may help in the design of intervention strategies for curbing the rising rural HIV epidemic.     

Parenteral transmission during excision and treatment of tuberculosis and trypanosomiasis may be responsible for the HIV-2 epidemic in Guinea-Bissau

BACKGROUND AND OBJECTIVE: The factors that led to the simultaneous emergence, decades ago, of HIV-1 in central Africa and HIV-2 in West Africa remain unclear. The low HIV-2-associated mortality enables epidemiological assessment of risk factors potentially relevant in the early stages of the epidemic. In Guinea-Bissau, its epicentre, HIV-2 became highly prevalent (approximately 15%) in cohorts of individuals born before 1962, but is now disappearing whereas HIV-1 prevalence is increasing. We sought to verify the hypothesis that parenteral transmission was the key factor in the building-up of the HIV-2 epidemic. DESIGN: Cross-sectional community survey of 1608 individuals aged > or = 50 years in Bissau. METHODS: Capillary blood was obtained for HIV serology. Associations between HIV-2 (alone or in dual HIV-1/HIV-2 infections) and exposures were measured with crude and adjusted odds ratios (AOR) and 95% confidence intervals (CI). RESULTS: Prevalence of HIV-2 was higher in women (160/1063; 15.1%) than men (45/545; 8.3%, P < 0.001). Among women, excision (AOR, 1.54; 95% CI, 1.08-2.18) was independently associated with HIV-2, as were age and being widowed (AOR, 1.88; 95% CI, 1.29-2.74). Among men, HIV-2 was not associated with sexually transmitted infections or transactional sex. In an analysis comprising men and women that was adjusted for age, sex, ethnic group and marital status, HIV-2 was associated with having received injections for the treatment of tuberculosis (AOR, 2.12; 95% CI, 1.11-4.05) or trypanosomiasis (AOR, 1.75; 95% CI, 1.03-2.97). CONCLUSIONS: Parenteral transmission through ritual excision and multiple injections during treatment of tuberculosis and trypanosomiasis contributed to the emergence of HIV-2 in Guinea-Bissau.     

Seroprevalence of HIV infection in rural South Africa.

OBJECTIVES: To establish the prevalence of HIV infection in rural South Africa and to investigate demographic factors that influence this prevalence. DESIGN: An anonymous HIV seroprevalence survey was performed in conjunction with a population-based malaria surveillance programme. SETTING: The rural area of northern Natal/KwaZulu, South Africa. PARTICIPANTS: A total of 5023 black African participants were recruited by malaria surveillance agents during house-to-house visits; each house in an endemic malaria area is visited approximately once every 6 weeks. Participants included 4044 healthy and 979 febrile individuals (i.e., suspected of having malaria). MAIN OUTCOME MEASURES: HIV-1 and HIV-2 serological status, degree of mobility, age and sex. RESULTS: Sixty of the 5023 blood specimens were confirmed to be HIV-1-antibody-positive by Western blot, an overall prevalence of 1.2% (95% confidence interval, 0.9-1.5). None of the specimens was positive for HIV-2 antibodies. After adjusting for age, presence of fever and migrancy, women had a 3.2-fold higher prevalence of HIV-1 infection than men. HIV-1 infection was approximately three times more common among subjects who had changed their place of residence recently (2.9 versus 1.0%, P < 0.01). CONCLUSIONS: The prevalence of HIV-1 infection is higher among women than men resident in rural Natal/KwaZulu, South Africa. This is at least in part the result of oscillatory migration, particularly of men who work in urban areas but have families and homes in rural areas. Migration is associated with a higher prevalence of HIV-1 infection, suggesting that improving social conditions so that families are not separated and become settled in their communities is one way to help reduce the spread of HIV-1.     

Prevalence of HIV and Chlamydia trachomatis infection in 15--19-year olds in rural Tanzania

OBJECTIVE: To estimate the prevalence of HIV and Chlamydia trachomatis (CT) infections amongst adolescents in rural Mwanza Region, Tanzania and their association with demographic variables. DESIGN: Population-based cross-sectional survey. METHODS: All 15--19-year olds living in households selected by random cluster sampling were invited to participate. After interview, urine was tested for HIV and CT. RESULTS: 9445 15--19-year olds were enrolled. HIV prevalence was 0.6% (95% CI: 0.4--0.8%) in males and 2.4% (95% CI: 2.0--2.8%) in females, and increased steeply with age (trend: P < 0.006 and P < 0.001, respectively). After adjustment for age, risk of HIV infection was significantly associated with female sex (OR=4.3), never having been to primary school in males (OR=2.7), and current symptoms of genital discharge (OR=2.3) or genital ulcer (OR=5.3) in females. The prevalence of CT was 1.0% (95% CI: 0.8--1.4%) in males and 2.4% (95% CI: 2.0-2.9%) in females. After adjustment for age, CT infection was associated with female sex (OR=2.4), reported current symptoms of STD (males OR=2.5, females OR=1.9) and positive leucocyte esterase (LE) test (males OR=3.1, females OR=2.6). Eighty-two percent of males and 79% of females with CT were asymptomatic. There was no association between CT and HIV infection in either sex. CONCLUSIONS: There is a high prevalence of HIV and CT amongst adolescents, especially young women, in this rural population, highlighting the need for effective interventions to improve adolescent reproductive health. The high rates of asymptomatic infection imply that innovative strategies are needed to reach and treat young people with STD.     

Urban/rural differences in prevalence and risk factors for intestinal helminth infection in southern Malawi

Urbanization may increase the risk of human infection with intestinal helminths. A cross-sectional survey was conducted to investigate the prevalence, intensity and potential risk factors of acquiring such infection, among children aged 3-14 years in similar urban and rural communities in southern Malawi. Stool samples were collected from 553 children (273 urban and 280 rural). The overall prevalence of helminth infection was significantly higher in the urban subjects than in the rural (16.5% v. 3.6%; P < 0.001), mostly because of differences in the prevalence of Ascaris lumbricoides infection. Living in an urban community was associated with a significantly higher risk of infection [odds ratio (OR) = 5.3; 95% confidence interval (CI) = 2.6-12.1], even after controlling for potential confounding factors. In the urban community, risk factors included having pools of water/sewage around houses (OR = 3.0; CI = 1.4-6.5), not wearing shoes (OR = 7.1; CI = 2.7-19.2), not attending school (OR = 2.8; CI = 1.2-6.5), having mothers with 4-8 years of education (OR = 5.2; CI = 2.0-14.0), and having mothers below 35 years of age (OR = 4.09; CI = 1.39-16.28). In this part of Africa, efforts to reduce helminth infections may best be focused on reducing geohelminth burden in urban areas.     

Prevalence of HIV-1 infection in the Kagera region of Tanzania: a population-based study

A population-based survey was carried out in the Kagera region of the United Republic of Tanzania in 1987 to determine the magnitude of HIV-1 infection and to study associated risk factors. The region was divided into one urban and three rural zones. A multistage cluster sampling technique was adopted. Antibodies to HIV-1 were determined by enzyme-linked immunosorbent assay and confirmed by Western blot analysis. A total of 2,475 adults (aged 15-54 years) and 1,961 children (aged 0-14 years) was studied. The overall prevalence of HIV-1 infection among adults was 9.6%, with a higher prevalence in the urban zone (24.2%) than in the three rural zones (10.0, 4.5 and 0.4%, respectively). The corresponding figures for children were 1.3% overall: 3.9% in the urban area and for the rural areas 1.2, 0.8 and 0.0%, respectively. The age-specific seroprevalence for adults was highest in the age group 25-34 years. The age-standardized sex-specific prevalence was higher among women than men in the urban zone, while it was the same in the rural zones. Change of sexual partners among adults was associated with an increased risk of HIV-1 seropositivity. Travelling outside the region but within the country was also found to be associated with increased risk of HIV-1 infection but only in the rural population.     

The association between hepatitis C virus and HIV-1 in preparatory cohorts for HIV vaccine trials in Thailand

OBJECTIVES: To study the association between hepatitis C virus (HCV) and HIV-1, and HCV seropositivity as an indicator of HIV-1 risk behavior for HIV vaccine preparatory cohorts in Thailand. DESIGN: Cross-sectional study of HIV-1-infected persons identified at screening for potential HIV vaccine trial cohort studies. METHODS: Sera from HIV-1-infected and uninfected volunteers was matched by age, sex, and community, and tested for HCV reactivity. Logistic regression methods were used to measure associations between HIV-1, HCV and other risk factors for HIV infection. RESULTS: The prevalence of HCV among HIV-negative controls was 8.3% (6/72) for men and 4.2% (5/118) for women. Co-infection with HIV and occurred in 50.7% (37/73) of men and 3.4% (4/118) of women. Among men who reported injection drug use (IDU), 96.4% (27/28) were HCV seropositive. No women reported IDU. HCV was associated with HIV infection [odds ratio (OR), 11.3; 95% confidence interval (CI), 4.4-29.3] and IDU (OR, 12.0; 95% CI, 3.4-41.9) among men, but not women (OR, 0.8; 95% CI, 0.2-3.0). After adjustment for potential confounding, HCV, but not IDU, remained strongly associated with HIV-1 infection among men (OR, 9.4; 95% CI, 2.7-32.6). CONCLUSIONS: The strong associations between HCV seropositivity, HIV-1 infection, and IDU history suggest that IDU was reported accurately in this study. The surprisingly high prevalence of HCV among HIV-1-infected young men may assist health policy makers in the choice of behavioral interventions for this important subgroup of the population.