Multiple ST clonal complexes, with a predominance of ST131, of Escherichia coli harbouring blaCTX-M-15 in a tertiary hospital in Tanzania.

The molecular epidemiology of 32 non-duplicate, CTX-M-15 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains, isolated from clinical samples, was investigated. Multilocus sequence typing revealed multiple sequence type clonal complexes: ST131 (12), ST405 (4), ST638 (3), ST38 (2), ST827 (2), ST224 (1), ST648 (1), ST46 (1) and two new sequence type clonal complexes (1845 and 1848) in 22 pulsed field gel electrophoresis clusters. The bla(CTX-M-15) gene was located on conjugative IncF plasmids. This is the first report of the worldwide emerging clonal complex ST131 linked to bla(CTX-M-15) in Tanzania and demonstrates the need for constant surveillance in developing countries to prevent the spread of these multiresistant isolates.

Prevalence of genotypic resistance to antiretroviral drugs in treatment-naive youths infected with diverse HIV type 1 subtypes and recombinant forms in Dar es Salaam, Tanzania.

As human immunodeficiency virus (HIV) diversity may have an impact on both vaccine efficacy and drug resistance, it is important to have knowledge of circulating genetic variants. With widespread use of antiretroviral (ARV) drugs in Africa, one of the major potential challenges is the risk of emergence of ARV drug-resistant HIV strains. This study aimed to determine the circulating HIV subtypes and recombinant forms, as well as the prevalence of ARV drug resistance mutations, among 75 treatment-naive HIV-infected youths in Dar es Salaam, Tanzania. Gag (n = 48), partial pol (n = 44), and partial env (n = 35) sequencing was performed; all three regions were sequenced in 26 samples. Evidence of infection with recombinant viruses was found in 12 (46%) participants; AC recombinants were the most commonly detected and they were identified in six (23%) participants. Of individuals infected with nonrecombinant strains, subtype A was most commonly detected in seven (27%) participants, followed by subtype C detected in six (23%) participants and subtype D detected in one (4%) participant. Among the pol sequences from 44 individuals, three (7%) had resistance to nucleoside reverse transcriptase (RT) inhibitors and four (9%) had nonnucleoside RT inhibitor resistance mutations. Of these, three (7%) individuals were infected with viruses with cross-resistance mutations to both classes of RT inhibitors. These resistant mutations were all associated with drugs currently used in first-line therapy and in the prevention of vertical transmission. This high prevalence of resistance mutations is of considerable concern in apparently drug-naive populations as it may result in treatment failure and the spread of ARV-resistant strains.

University partnership to address the shortage of healthcare professionals in Africa.

The shortage of qualified health professionals is a major obstacle to achieving better health outcomes in many parts of the world, particularly in Africa. The role of health science universities in addressing this shortage is to provide quality education and continuing professional development opportunities for the healthcare workforce. Academic institutions in Africa, however, are also short of faculty and especially under-resourced. We describe the initial phase of an institutional partnership between the Muhimbili University of Health and Allied Sciences (MUHAS) and the University of California San Francisco (UCSF) centred on promoting medical education at MUHAS. The challenges facing the development of the partnership include the need: (1) for new funding mechanisms to provide long-term support for institutional partnerships, and (2) for institutional change at UCSF and MUHAS to recognize and support faculty activities that are important to the partnership. The growing interest in global health worldwide offers opportunities to explore new academic partnerships. It is important that their development and implementation be documented and evaluated as well as for lessons to be shared.

Prevalence of serum antibodies to human papilloma virus in patients with genital ulcer disease in an urban population of Tanzania.

BACKGROUND: The epidemiology of human papillomavirus (HPV) in Tanzania is largely unknown both in risk groups and in the general population. OBJECTIVE: To determine the cumulative seroprevalence of selected HPV types in order to evaluate exposure to HPV in urban Tanzania. METHOD: In a cross-sectional study, sera of 200 patients of both sexes with genital ulcer disease (GUD) and sera of 60 male blood donors and 60 pregnant women were tested for antibodies to the oncogenic HPV types 16, 18, 31, 33, 35, 51 and 52 using an ELISA based on virus-like particles (VLP). RESULTS: The overall seroprevalence of HPV types for all patients with GUD was 83% and 77% for women and men, respectively. For pregnant women and male blood donors, the corresponding percentages were 55% and 15%, respectively. The most common HPV types were 16, 18 and 52. Infection with multiple types was more than 10 and 5 times more frequent than infection with a single type 16 in patients with GUD and in pregnant women, respectively. The seroprevalence to HPV types 16, 18, 51 and 52 was considerably higher in HIV-positive patients with GUD than in HIV-negative patients. CONCLUSIONS: Infections with the oncogenic HPV types 16, 18 and 52 are common among patients with GUD and pregnant women in urban Tanzania, emphasising the need for control, treatment and implementation of appropriate HPV vaccine programmes.

Molecular characterization of Haemophilus ducreyi isolates from different geographical locations.

The technique of random amplified polymorphic DNA (RAPD) was adapted and optimized to study Haemophilus ducreyi isolates. A panel of 43 strains isolated from chancroid patients from different countries in Africa, Europe, North America, and Asia were characterized. The strains were also studied with respect to lipooligosaccharide (LOS) migration and immunoblotting patterns and the presence of cytolethal distending toxin genes. The RAPD method with the OPJ20 primer generated nine banding patterns (1 to 9). The majority of the isolates were clustered into two major profiles, 14 and 13 strains into profiles 1 and 2, respectively, and just a few strains revealed patterns 3 and 4. The isolates from Thailand were exceptional in that they showed greater diversity and were represented by six different RAPD patterns, i.e., patterns 3 and 5 to 9. The LOS migration and immunoblotting analyses revealed two different patterns, which indicated long and short forms of LOS; the former was found in 20/23 tested strains. Two strains that expressed the short form of LOS were grouped into RAPD pattern 4. The absence of cdtABC genes was observed in only 4/23 strains, and three of these isolates were assigned to RAPD pattern 4. Our results showed limited genotypic and phenotypic variations among H. ducreyi strains, as supported by the conserved RAPD and LOS profiles shared by the majority of the studied strains. However, the RAPD method identified differences between strains, including those from different geographic areas, which indicate the potential of RAPD as an epidemiological tool for the typing of H. ducreyi isolates in countries where chancroid is endemic.

Comparison of the performance of SD bioline syphilis 3.0 assay with the RPR test for the syphilis screening in Dar Es Salaam, Tanzania

Background:World Health Organization in 2003 launched Sexually Transmitted Diseases Diagnostics Initiative (SDI) with mission to promote the development; evaluation and application of sexually transmitted infection diagnostic tests including syphilis screening appropriate for use in primary health care settings in developing countries.Objective: To evaluate the performance of SD BIOLINE Syphilis 3.0 test (Standard Diagnostics Inc.; South Korea) using routine serum samples from blood donors; antenatal clinic attendees and out patients.Settings: Mwananyamala and Amana District Hospitals; and Muhimbili University College of Health Sciences; Department of Microbiology and Immunology; Dar es Salaam; TanzaniaMethods: A total of 498 serum samples were initially tested on both SD BIOLINE Syphilis 3.0 and rapid plasma reagin (RPR) tests and were then confirmed on Treponema pallidum hemaagglutination (TPHA) test.Results: The overall seroprevalence of syphilis was 5.6(28/498) on TPHA; 8.2(41/498) on SD BIOLINE Syphilis 3.0 and 9.8(49/498) on RPR tests. The SD BIOLINE test had higher sensitivity (79vs. 68) and specificity (96vs. 94) compared to RPR test.Conclusion: The overall sensitivity (79) of SD BIOLINE syphilis 3.0 test found is low whereas specificity (96) found is similar compared to the previous evaluation but higher compared to the sensitivity (68) and specificity (94) of the currently used RPR test. SD BIOLINE syphilis 3.0 test offers better sensitivity; specificity and test efficiency than the currently used RPR test.Recommendation: The SD BIOLINE syphilis 3.0 test offers better sensitivity; specificity; test efficiency and operational characteristics than the currently used RPR test and may be adopted for use in syphilis screening in our settings

Profile of suicide in Dar es Salaam.

OBJECTIVE: To investigate individual socio-demographic characteristics of suicides, the reasons, methods and means employed to commit suicide. DESIGN: A descriptive prospective study of suicides. A structured questionnaire was employed to enquire the details of the itemised objectives. SETTING: Muhimbili National Hospital--in urban Dar es Salaam. SUBJECTS: Fifty three males and 47 females consecutive suicides aged 15 to 59 years RESULTS: The mean age for suicides was found to be 28.2 years. Males were more than females and were ten years older. Sixty two percent of the subjects were single, 30% married. Seventy two percent had primary school education, 19% secondary education. Main reasons for committing suicide were established in 61 cases of which 57.3% (35/61) were due to severe marital and family conflicts, overwhelming disappointments in love affairs and unwanted pregnancies. Eleven subjects with chronic somatic illnesses killed themselves due to unbearable physical pain and overwhelming economic deprivations motivated ten subjects to take their lives. Sixty nine subjects poisoned themselves predominantly using anti-malarials and pesticides while 27 hanged themselves. A third of the suicides consumed alcohol frequently and a quarter of the suicides were HIV positive, a rate twice the national prevalence for sexually active adults. CONCLUSION: Comparatively, women became vulnerable to suicide at a younger age. Dysfunctional social networks played a predominant role among suicides. Family and marital conflicts need closer social attention and timely counseling. Patients with chronic medical conditions and frequent alcohol use need effective exploration concerning suicidal ideation to avert self-annihilation. A policy to control prescriptions of toxic drugs including pesticides is overdue.

Baseline survey of sexually transmitted infections in a cohort of female bar workers in Mbeya Region, Tanzania.

OBJECTIVES: To determine baseline prevalence of sexually transmitted infections (STI) and other reproductive tract infections (RTI) and their association with HIV as well as sociodemographic and behavioural characteristics in a newly recruited cohort of female bar workers in Mbeya Region, Tanzania. METHODS: 600 female bar workers were recruited from 17 different communities during September to November 2000 and underwent gynaecological examination, laboratory testing for HIV/STI, and interviews using structured questionnaires. RESULTS: HIV-1 seroprevalence was 68%. Prevalences of STI/RTI were high titre syphilis (TPPA/RPR >/=1/8), 9%; herpes simplex virus 2 antibodies, 87%; chlamydia, 12%; gonorrhoea, 22%; trichomoniasis, 24%; and bacterial vaginosis, 40%. HIV infection was associated with TPPA and HSV-2 seropositivity, bacterial vaginosis and clinically diagnosed genital ulcers, blisters, and warts. Reported high risk sexual behaviour during the past year (having multiple casual partners) was associated with prevalent STI. CONCLUSION: Female bar workers in Mbeya are at high risk of STI and HIV infection. Targeted STI/HIV prevention interventions for these women and their sexual partners need to be reinforced. Methods should be sought to improve healthcare seeking and to provide easily accessible and affordable STI care services.

Prevalence and clinical presentation of HIV infection among newly hospitalised surgical patients at Muhimbili National Hospital, Dar es Salaam, Tanzania.

BACKGROUND: In Tanzania information is lacking on the prevalence of HIV infection in surgical patients in tertiary care facilities, in whom there are many points of special interest. OBJECTIVE: To determine the prevalence of HIV infection and associated clinical and demographic features among hospitalised surgical patients at Muhimbili National Hospital (MNH). SETTING: Muhimbili National Hospital. MATERIALS AND METHODS: Consecutive newly admitted patients were tested for HIV antibodies after pre-test counselling. Sera were tested using a dual ELISA algorithm. The data were analysed to determine the prevalence of HIV infection and relationships of serostatus with clinical and socio-demographic characteristics. RESULTS: Of 1,534 patients admitted during the study, 1,031(67.2%) consented to HIV testing following pre-test counselling. The prevalence of AIDS-related clinical features in patients who declined to be HIV tested was similar to that of seronegative patients, but significantly lower than that of seropositive patients. The overall age-adjusted HIV prevalence was 10.5% (95% CI = 9.9-14.0). The highest age-specific HIV prevalence was in the age group 35-44 years at 27.9%. No one was infected in the age group 0-4 years (n = 111). Differences in prevalence between age groups were statistically significant (p < 0.0001). Patients with granulomatous and suppurative infections had HIV prevalence of 28.3%. Twenty of 124 seropositive patients (16.1%) died in hospital compared to 58 of 907(6.4%) of seronegative patients (p = 0.0001). CONCLUSION: At Muhumbili National Hospital overall HIV prevalence in hospitalised surgical patients were 10.5%, compared to an overall national prevalence of 6.7%. Patients in the age groups 25 to 34 and 35 to 44 years had HIV seroprevalence of 26.8% and 27.9% respectively. Patients with infective conditions had the highest HIV prevalence. HIV seropositive patients were associated with higher hospital mortality than seronegative patients.

Tetanus immunity among pregnant women attending antenatal care in Dar es Salaam, Tanzania.

This study was conducted to investigate immunity to tetanus among pregnant women with verbal histories or documentation of having been vaccinated under the current five-dose tetanus toxoid (TT) schedule. It examined sera from 176 pregnant women attending antenatal care at Muhimbili Medical Centre in Dar es Salaam, Tanzania. Tetanus antitoxin level of 0.1 IU/ml was considered protective. Our findings show that 94.9% of women had tetanus antitoxin > or = 0.1 IU/ml. Multivariate analysis revealed that time after last vaccination, TT doses received and TT vaccination status explained 7.5%, 5.7% and 2.3% of variations in tetanus antitoxin levels respectively. Pregnant women with non-protective levels of tetanus antitoxin (5.1%) pose great risks of neonatal tetanus to their newborns and are also susceptible to maternal tetanus. Proper keeping of TT vaccination records is vitally important to avoid hyper-immunisation.

Immunity to tetanus in male adults in Dar es Salaam, Tanzania.

OBJECTIVE: To determine immunity to tetanus in male blood donors with previous diphtheria-pertussis-tetanus (DPT)/tetanus toxoid (TT) vaccination. DESIGN: A cross sectional study, conducted in September 1999. SETTING: Blood bank, Muhimbili Medical Centre, Dar es Salaam, Tanzania. METHODS: Using an antigen competition ELISA technique, serum tetanus anti-toxin levels in two hundred male blood donors were determined. RESULTS: Vaccination history was absent in 43 (21.5%) blood donors, whereas 60 (30%) and 97 (48.5%) reported childhood DPT and TT vaccination, respectively. Tetanus anti-toxin was undetectable in 47 (23.5%) blood donors and the levels were below that considered protective (> or = 0.1 IU/ml) in 25 (12.5%). Among those with undetectable level, 43 (91.5%) had no vaccination history. Time after last DPT/TT vaccination correlated significantly with tetanus anti-toxin levels (r2=-0.331, p=0.001). In multivariate analysis, TT doses received and time after last vaccination explained 4.8% and 29.4%, respectively, of the variations in tetanus anti-toxin levels. CONCLUSION: Seventy two (36%) male blood donors were susceptible to tetanus and the susceptibility was highest from 48 years. A regular TT booster dose at 10 yearly intervals is recommended to provide adequate and long lasting immunity in male adults. Proper keeping of vaccination records is emphasised.

HIV counseling and testing of pregnant women in sub-Saharan Africa: experiences from a study on prevention of mother-to-child HIV-1 transmission in Dar es Salaam, Tanzania.

The aim of this study was to determine the acceptability of HIV counseling and testing and participation in a mother-to-child HIV-1 transmission intervention study using antiretroviral therapy in Dar es Salaam, Tanzania, one of the sites for the Joint United Nations Program on AIDS (UNAIDS) multicenter Petra trial. HIV testing was offered to all pregnant women who visited three prenatal clinics in Dar es Salaam before 34 weeks' gestation. Group or individual pretest counseling was performed by trained midwives. Laboratory diagnosis of HIV infection was based on two sequential anti-HIV enzyme-linked immunosorbent assays. Posttest counseling was given 2 weeks later to women who wished to know their HIV status. HIV testing was offered to a total of 10,010 pregnant women from June 1996 to May 1998, of whom 76.4% (7647 of 10,010) agreed to be tested. The prevalence of HIV-1 infection was 13.7% (1050 of 7647). Overall, 68.1% (5205 of 7647) returned for their results. Of the HIV-1-seropositive respondents, 27.4% (288 of 1050) agreed to participate in the Petra trial after fulfilling the eligibility criteria. Only 16.7% (48 of 288) of the enrolled women disclosed their positive HIV serostatus to their sexual partners. The main reasons for not disclosing the HIV serostatus were fear of stigma and divorce. Sixty percent (29 of 48) of the informed sex partners agreed to be tested for HIV and 69% (20 of 29) tested HIV seropositive. Pregnancy recurrence rate was 4.4 per 100 women years (18 pregnancies during 408 women years of follow-up) with 10 of 18 (55.6%) women not wanting to carry the pregnancy to term. In conclusion, this information is useful in planning intervention programs for prevention of mother-to-child HIV-1 transmission and it shows that improvements are required in counseling.

Affordable CD4+ T cell counts by flow cytometry. II. The use of fixed whole blood in resource-poor settings.

We tested the feasibility and precision of affordable CD4+ T cell counting in resource-poor settings using a recently standardised fixative, TransFix in whole blood (WB) by flow cytometry (FCM). The precision of the assays was established under optimal conditions for single-platform FCM such as the volumetric CytoronAbsolute and the bead-based FACSCan. Fresh WB samples from HIV-seropositive and seronegative patients were tested in Tanzania and South Africa, fixed and sent to the UK for reanalysis 7 days later. Correlation, bias and limits of agreements were analysed by linear regression and the Bland-Altman test. Absolute CD4+ T cell counts remained stable for at least 10 days when TransFix was added to WB in 1:10 dilution at 20-25 degrees C, and for 7 days when added in 1:10 or 1:5 dilution to samples stored to mimic 'tropical' conditions at 37 degrees C. Higher temperatures such as 42 degrees C were tolerated for only short periods since the recovery had decreased to 63% by day 3. The reproducibility of lymphocyte subset analysis remained unchanged by TransFix with coefficient of variations <6% for all T cell subsets. Absolute CD4+ T cell counts and CD4+ T cell % values on fixed samples in the UK showed a high correlation with the results using fresh samples in Tanzania (r=0.993 and 0.969, respectively) and with the samples handled in Johannesburg (r=0.991 and 0.981) with minimal bias. Primary CD4 gating using only a single CD4 antibody also remained accurate in TransFixed samples (r=0.999). Thus, TransFix permits optimal fixation and transport of WB samples in the developing world for FCM to local regional laboratories and for quality assurance in international centres. When used together with inexpensive primary CD4 gating, TransFix will allow reliable and affordable CD4+ T cell counting by FCM in resource-poor settings.

Meningitis propagation in southern Tanzania: the role of a village video show.

An outbreak of meningitis with 85 secondary cases and an unusually high attack rate of 16% occurred in a rural village in southern Tanzania. We investigated risk factors for clinical illness in a community-based case-control study. Attending a commercial mobile video show carried an age- and sex-adjusted odds ratio of 8.0 (95% confidence interval: 3.8-16.8). The videos had been shown in a windowless and overcrowded storeroom and had been attended by the primary case, a visitor from neighbouring Mozambique who died from meningitis on the following day. We conclude that mobile video shows, which have become popular in many developing countries, constitute a potential health hazard in areas prone to meningitis epidemics.

Antibodies to tetanus toxoid in women of childbearing age in Dar es Salaam and Bagamoyo, Tanzania.

Our aim was to determine tetanus immunity in women of childbearing age (15-44 years) with histories and/or documentation of having been vaccinated with Tetanus Toxoid (TT) under the Expanded Programme on Immunization in Dar es Salaam and Bagamoyo, Tanzania. Using an ELISA technique, serum levels of TT antibody, antibody avidity and distribution of TT IgG subclass antibodies were determined in 207 apparently healthy women. A TT antibody level of 0.1 IU/ml was considered protective. 99% and 100% of women in Dar es Salaam and Bagamoyo, respectively, had a TT antibody level > or = 0.1 IU/ml. Anti-toxin binding avidity was found to be high in most of the women. In addition to TT IgG3 subclass antibody, TT IgG1 subclass antibody was the most dominant subclass type. A substantial number of women also had TT IgG2 and TT IgG4 subclass antibody responses. A better recording system on TT immunization is recommended to avoid hyper-immunization of women and to optimize the cost-effectiveness of the immunization programme.

Risk factors for HIV-1 seroprevalence among family planning clients in Dar es Salaam, Tanzania.

Between March and September of 1995, women receiving family planning (FP) services in three large clinics in Dar es Salaam, Tanzania were invited to participate in a cross-sectional study. Consenting women were interviewed to obtain information about HIV risk factors, and blood for HIV testing was collected. The prevalence of HIV was 16.9% (95% CI: 14.4%-19.3%). The risk of HIV increased significantly with age. Compared with married women, the risk of HIV was significantly higher among cohabiting women (age-adjusted OR = 2.3; 95% CI = 1.5-3.5) and among women who were single, divorced or widowed (age-adjusted OR = 2.3; 95% CI = 1.2-4.4). The risk of HIV was also significantly higher among hotel workers (age-adjusted OR = 4.3; 95% CI = 1.4-12.9). Women with laboratory evidence of sexually transmitted diseases were at increased risk of HIV. This study shows that HIV is a major public health problem among FP clients in Tanzania. Innovative HIV interventions are needed to reduce further spread of HIV infection.

Prevalence of HIV type 1 infection, associated clinical features and mortality among hospitalized children in Dar es Salaam, Tanzania.

The aim of this study was to determine the prevalence of HIV-1 infection, the clinical spectrum of HIV-1-associated conditions and HIV-1-associated mortality among children hospitalized in the medical paediatric wards at Muhimbili Medical Centre (MMC), Dar es Salaam, Tanzania. All children admitted to the medical paediatric wards of MMC between August 1995 and January 1996 were eligible for the study. Testing for HIV antibodies was done using 2 consecutive enzyme linked immunosorbent assays (ELISAs). ELISA-reactive samples from children aged 18 months and below were further tested by a recently developed heat-denatured p24 antigen assay. The prevalence of HIV-1 infection among the 2015 children studied was 19.2%. When present for 14 days or more, fever, cough, diarrhoea, ear discharge, oral ulcers and skin rash were all significantly more common in HIV-1-infected than in HIV-uninfected children (p < 0.001). In the multivariate analysis cough, ear discharge, oropharyngeal ulcers and skin rash were found to be the most important symptoms. Clinical signs found to be significantly associated with HIV-1 infection in the univariate analysis were wasting, stunting, hair changes, oral thrush, oropharyngeal ulcers, lymphadenopathy, lung consolidation and lung crepitations (p < 0.001). In the multivariate analysis, oral thrush, lung crepitations, cervical lymphadenopathy, wasting and inguinal lymphadenopathy were found to be the most important signs. The 3 most common diagnoses in HIV-1-infected children were acute respiratory infection (ARI) (39.4%), malnutrition (38.1%) and tuberculosis (19.3%), while in HIV-uninfected children they were malaria (47.0%), ARI (25.0%) and malnutrition (16.1%). The mortality rate was 21.4% in HIV-1-infected children and 8.4% in HIV-uninfected children (p < 0.001). In conclusion, the prevalence of HIV-1 infection among hospitalized children at the main hospital in Dar es Salaam was high and associated with high mortality. Many symptoms and signs are indicative of HIV-1 infection, but appropriate laboratory testing is required for diagnosis.

Evaluation of a prototype Amplicor PCR assay for detection of human immunodeficiency virus type 1 DNA in blood samples from Tanzanian adults infected with HIV-1 subtypes A, C and D.

BACKGROUND: In previous evaluations, the standard Amplicor HIV-1 DNA PCR test (Roche Diagnostic Systems) has been reported to have low sensitivity for the detection of some non-B HIV-1 subtypes. It has therefore become necessary to determine the performance of commercially available as well as prototype HIV-1 PCR assays for HIV-1 DNA detection in samples from various geographical settings, in order to assess their ability to detect the different HIV-1 genotypes. OBJECTIVES: To determine the performance of the prototype Roche Amplicor version 1.5 PCR test in comparison to that of the standard Roche Amplicor PCR test for the detection of HIV-1 DNA in blood samples from HIV-1 seropositive pregnant Tanzanian women infected with various HIV-1 subtypes. STUDY DESIGN: This was a cross-sectional study done on 161 blood samples collected from 106 HIV-1 seropositive and 55 seronegative asymptomatic pregnant women attending antenatal clinic in Dar es Salaam, Tanzania. METHODS: Cell pellets for PCR were prepared from EDTA blood by the Amplicor whole blood PCR sample preparation method. Plasma was used for HIV serology by enzyme linked immunosorbent assays. Subtyping was done by the heteroduplex mobility assay (HMA) using cell pellets and/or plasma. RESULTS: The sensitivities of the prototype PCR and the standard assays were 99.1% (105/106) and 97% (99/102), respectively. All samples from 55 HIV-1 seronegative women were negative by both PCR assays. Among the 101 samples subtyped by HMA, 48 (47%) were subtype A, 30 (30%) subtype C, 20 (20%) subtype D and 3 (3%) were indeterminate. In the standard DNA PCR assay, a statistically significantly higher proportion of subtype A samples had a low level of reactivity as measured as optical density compared with the subtypes C and D samples while in the prototype assay all three subtypes showed a high level of reactivity. CONCLUSIONS: The Amplicor version 1.5 DNA PCR test has a high sensitivity for the detection of HIV-1 DNA in blood samples from Tanzanian adults. Since performance of this assay does not appear to be influenced by differences in HIV-1 subtypes A, C and D, it has the potential for use in the detection of HIV-1 DNA in samples from geographic areas where these subtypes are prevalent.

The prevalence and incidence of HIV-1 infection and syphilis in a cohort of police officers in Dar es Salaam, Tanzania: a potential population for HIV vaccine trials.

OBJECTIVES: To assess the suitability of a cohort of police officers in Dar es Salaam for HIV vaccine trials by determining the prevalence and incidence of HIV-1 infection, active syphilis and their associated factors. DESIGN AND SETTING: An open cohort study of police officers in Dar es Salaam, Tanzania. METHODS: Recruitment of police officers began in 1994. A standardized questionnaire was completed at enrolment and subsequent visits. HIV antibodies were determined using two consecutive enzyme-linked immunosorbent assays. Samples repeatedly discordant on the two tests were tested by a Western blot assay. Treponema pallidum antibodies were first determined by Venereal Disease Research Laboratory (VDRL) test and reactive sera were confirmed by Treponema pallidum hemagglutination test. RESULTS: At the end of 1996 a total of 2850 police officers had been recruited of whom 2733 (96%) consented to be tested for HIV. The overall HIV-1 seroprevalence at recruitment was 13.8% (378 of 2733). Females had a significantly higher HIV-1 seroprevalence, 18.0% (55 of 306), as compared to males, 13.3% (323 of 2427), P< 0.05. From a total of 2215 married police officers, 585 (26.4%) responded to a question on extramarital sex within the previous 3 months of whom 36.2% (212 of 585) admitted to have had at least one extramarital sexual intercourse. Condoms were not used during these encounters by 178 of 212 (84.0%). As of 31st December 1998, among the 1524 males observed for 2553 person-years (PYAR), 50 had seroconverted and among 200 females observed for 357 PYAR, eight had seroconverted. The overall crude HIV-1 incidence was thus 19.9/1000 PYAR; 19.6 and 22.4/1000 PYAR for males and females, respectively. The overall prevalence and incidence of active syphilis were 3.1% (88 of 2850) and 8.6/1000 PYAR (26 of 3149), respectively. Males had a higher prevalence of active syphilis, 84 of 2525 (3.3%) than females, five of 325 (1.5%), P = 0.09. CONCLUSIONS: There was high risk sexual practice including low condom use in this cohort of police officers. The incidence and prevalence of HIV infection were high. Police officers in Dar es Salaam are therefore a potential population group for HIV vaccine evaluation.