High prevalent and incident HIV-1 and herpes simplex virus 2 infection among male migrant and non-migrant sugar farm workers in Zambia.

BACKGROUND: More insight is needed regarding risk factors for prevalent and incident HIV-1 infection among male farm workers in Sub-Saharan Africa to control the HIV-1 epidemic. METHODS: Male farm workers were recruited from a sugar estate in Zambia to participate in a prospective cohort study. Questionnaire data were collected via interview, and testing was conducted for HIV-1, herpes simplex virus type 2 (HSV-2), and syphilis infection at baseline and follow-up between May 2006 and September 2007. RESULTS: Among 1062 workers enrolled, HIV-1 prevalence at baseline was 20.7%. Testing HSV-2 seropositive (adjusted odds ratio (AOR) 5.4, 95% CI 3.6 to 8.1), self-reported genital ulcers in the past year (AOR 2.8, 95% CI 1.9 to 4.2), and being widowed (AOR 3.7, 95% CI 2.0 to 6.9) were significantly associated with prevalent HIV-1 infection. The HIV-1 incidence among 731 initially negative participants with at least one follow-up visit was 4.1 per 1000 person-months (95% CI 2.6 to 5.7); seroconversion was independently associated with prevalent HSV-2 infection (adjusted hazard ratio (AHR) 2.4, 95% CI 1.0 to 5.8) and incident HSV-2 infection (AHR 18.0, 95% CI 4.2 to 76.3). HIV-1 prevalence and incidence rates were similar among migrant and non-migrant workers. CONCLUSIONS: HIV-1 prevalence and incidence were high, and HSV-2 infection was a risk factor for HIV-1 acquisition. There is an urgent need to expand HIV-1 prevention programmes tailored to farm workers and their communities.

Non-sexual transmission of Trichomonas vaginalis in adolescent girls attending school in Ndola, Zambia.

OBJECTIVES: To identify risk factors for trichomoniasis among young women in Ndola, Zambia. METHOD: The study was a cross-sectional study among adolescent girls aged 13-16 years in Ndola, Zambia. Study participants were recruited from schools in selected administrative areas that represented the different socio-economic strata in town. Consenting participants were interviewed about their socio-demographic characteristics; sexual behaviour; and hygiene practices. Self-administered vaginal swabs were tested for Trichomonas vaginalis. HSV-2 antibodies were determined on serum to validate the self-reported sexual activity. RESULTS: A total of 460 girls participated in the study. The overall prevalence of trichomoniasis was 27.1%, 33.9% among girls who reported that they had ever had sex and 24.7% among virgins. In multivariate analysis the only statistically significant risk factor for trichomoniasis was inconsistent use of soap. For the virgins, none of the risk factors was significantly associated with trichomoniasis, but the association with use of soap (not always versus always) and type of toilet used (pit latrine/bush versus flush toilet) was of borderline significance. CONCLUSION: We found a high prevalence of trichomoniasis in girls in Ndola who reported that they had never had sex. We postulate that the high prevalence of trichomoniasis in virgins in Ndola is due to non-sexual transmission of trichomoniasis via shared bathing water and inconsistent use of soap.

Identification of amino acid substitutions associated with neutralization phenotype in the human immunodeficiency virus type-1 subtype C gp120.

Neutralizing antibodies (Nabs) are thought to play an important role in prevention and control of HIV-1 infection and should be targeted by an AIDS vaccine. It is critical to understand how HIV-1 induces Nabs by analyzing viral sequences in both tested viruses and sera. Neutralization susceptibility to antibodies in autologous and heterologous plasma was determined for multiple Envs (3-6) from each of 15 subtype-C-infected individuals. Heterologous neutralization was divided into two distinct groups: plasma with strong, cross-reactive neutralization (n=9) and plasma with weak neutralization (n=6). Plasma with cross-reactive heterologous Nabs also more potently neutralized contemporaneous autologous viruses. Analysis of Env sequences in plasma from both groups revealed a three-amino-acid substitution pattern in the V4 region that was associated with greater neutralization potency and breadth. Identification of such potential neutralization signatures may have important implications for the development of HIV-1 vaccines capable of inducing Nabs to subtype C HIV-1.

Management of pulmonary tuberculosis patients in an urban setting in Zambia: a patient's perspective.

BACKGROUND: Zambia continues to grapple with a high tuberculosis (TB) burden despite a long running Directly Observed Treatment Short course programme. Understanding issues that affect patient adherence to treatment programme is an important component in implementation of a successful TB control programme. We set out to investigate pulmonary TB patient's attitudes to seek health care, assess the care received from government health care centres based on TB patients' reports, and to seek associations with patient adherence to TB treatment programme. METHODS: This was a cross-sectional study of 105 respondents who had been registered as pulmonary TB patients (new and retreatment cases) in Ndola District between January 2006 and July 2007. We administered a structured questionnaire, bearing questions to obtain individual data on socio-demographics, health seeking behaviour, knowledge on TB, reported adherence to TB treatment, and health centre care received during treatment to consenting respondents. RESULTS: We identified that respondents delayed to seek treatment (68%) even when knowledge of TB symptoms was high (78%) or when they suspected that they had TB (73%). Respondent adherence to taking medication was high (77%) but low adherence to submitting follow-up sputum (47%) was observed in this group. Similarly, caregivers educate their patients more often on the treatment of the disease (98%) and drug taking (100%), than on submitting sputum during treatment (53%) and its importance (54%). Respondent adherence to treatment was significantly associated with respondent's knowledge about the disease and its treatment (p < 0.0001), and with caregiver's adherence to treatment guidelines (p = 0.0027). CONCLUSIONS: There is a need to emphasise the importance of submitting follow-up sputum during patient education and counselling in order to enhance patient adherence and ultimately treatment outcome.

Diversity of Mycobacterium tuberculosis genotypes circulating in Ndola, Zambia.

BACKGROUND: Tuberculosis (TB) is one of the major public health problems in Zambia. However, information about lineages of M. tuberculosis complex (MTBC) isolates useful for epidemiology investigations is unknown. In this study, we investigated the diversity of MTBC isolates from Ndola, a typical Zambian urbanized city with a documented high HIV prevalence. METHODS: This was part of a prospective cohort study in subjects with sputum smear-positive pulmonary TB. Spoligotyping was used to genotype the MTBC isolates and establish the circulating lineages. The 15-locus Mycobacterial Interspersed Repetitive Units - Variable Number Tandem Repeats (MIRU-VNTR) typing was used to study recent transmission. RESULTS: A total of 98 different spoligotypes were identified among 273 MTBC isolates. The majority (64.8%) of the isolates belonged to 9 known families, while 96 (35.2%) of the isolates were orphans. While LAM (41.8%) was the largest spoligotype family observed, most of the isolates (87.7%) belonging to the SAF1 family, with a significant portion coming from the T (13.6%), and X (5.9%) families. A few isolates (3.6%) belonged to the CAS, EAI, H, S, X1-LAM9 or U families. MIRU-VNTR typing was highly discriminatory (h = 0.988) among the 156 isolates tested in our sample, and increased the discrimination among 82 SAF1 isolates from 6 to 46 distinct patterns. In addition, 3.2% (5/156) of cases with available MIRU-VNTR results harbored more than one MTBC strain. CONCLUSIONS: Our findings show a limited diversity of MTBC in Ndola with a high clustering rate (37.7%), which indicates that recent transmission plays an appreciable role in the dynamics of TB disease in this setting. This conclusion emphasizes the importance of early diagnosis and timely treatment. The results also confirm that MIRU-VNTR typing is suitable for studying the molecular epidemiology of TB in Ndola.

Low Occurrence of Tuberculosis Drug Resistance among Pulmonary Tuberculosis Patients from an Urban Setting, with a Long-Running DOTS Program in Zambia.

We set out to determine the levels of Mycobacterium tuberculosis resistance to first- and second-line TB drugs in an urban population in Zambia. Sputum samples were collected consecutively from all smear-positive, new and previously treated patients, from four diagnostic centres in Ndola between January and July 2006. Drug susceptibility testing was performed using the proportion method against four first- and two second-line TB drugs. Results. Among 156 new cases, any resistance was observed to be 7.7%, monoresistance to isoniazid and rifampicin was 4.5% and 1.3%, respectively. Of 31 retreatment cases, any resistance was observed to be 16.1%, monoresistance to isoniazid and rifampicin was 3.3% for each drug, and one case of resistance to both isoniazid and rifampicin (multidrug resistance) was detected. No resistance to kanamycin or ofloxacin was detected. Conclusion. Although not representative of the country, these results show low levels of drug resistance in a community with a long-standing DOTS experience. Resource constrained countries may reduce TB drug resistance by implementing community-based strategies that enhance treatment completion.

Trichomonas vaginalis is highly prevalent in adolescent girls, pregnant women, and commercial sex workers in Ndola, Zambia.

OBJECTIVES: The aim of the study was to assess the prevalence of Trichomonas sp. infection among adolescent girls, pregnant women, and commercial sex workers in Ndola, Zambia. METHODS: A cross-sectional study was conducted among 460 girls attending school, 307 pregnant women, and 197 commercial sex workers. Self-collected specimens from the vagina, rectum, and mouth were tested by polymerase chain amplification assays for the presence of Trichomonas vaginalis, Pentatrichomonas hominis, and Trichomonas tenax. Genotyping was performed on specimens that tested positive for T. vaginalis. RESULTS: The prevalence of vaginal infection with T. vaginalis was 24.6% among the adolescents, 32.2% among the pregnant women, and 33.2% among the commercial sex workers. Trichomonads other than T. vaginalis were rarely found in the vagina, rectum, and mouth. The presence of T. vaginalis in the rectum was associated with T. vaginalis in the vagina. T. tenax was also detected in the vagina. A total of 9 actin genotypes of T. vaginalis were identified. The distribution of the actin genotypes of T. vaginalis was similar in the 3 study groups. CONCLUSION: We detected high prevalence rates of trichomoniasis among women in Ndola, Zambia. Prevalence among adolescent girls was lower than among pregnant women and commercial sex workers but was still high. We were not able to detect differences in T. vaginalis actin genotypes among the 3 study groups.