Mosquito larval productivity in rice-fields infested with Azolla in Mvomero District, Tanzania.

Azolla (Salviniales: Azollaceae) is known to reduce oviposition and adult emergence of a number of mosquito species. Several species of Azolla are reportedly indigenous to Tanzania. However, the potential of Azolla as a biocontrol agent against malaria mosquitoes has not been evaluated in the country. This cross-sectional study was carried out to assess mosquito larval productivity in irrigated rice-fields infested with Azolla in Mvomero District, Tanzania. A systematic larval sampling covering all open water bodies along designed transect was carried in rice-fields. Larval density was estimated by dipping water bodies with or without Azolla. The degree of Azolla coverage was categorized as 0%, <50%, 50%, and >80%. Larvae densities were categorised as low (<50/m2), medium (50-500/m2) and high (> or = 500/m2) productivity. A total of 120 water bodies were surveyed and 105 (87.5%) had Azolla microphyla and A. pinnata at varying degrees of coverage. Of the total 105 water bodies with Azolla, 80 (76.2%) had a green Azolla mat, and 25 (23.8%) a brown Azolla mat. Eighty-eight (73.3%) of the sites were infested with anophelines and 109 (90.8%) with culicine larvae. Seventy percent of all water bodies contained anophelines and culicines in sympatric breeding, while 20.8% and 3.3% had only culicines and anophelines, respectively. The majority (82%) of mosquito breeding sites were found in area with Azolla substrate. Mosquito larva productivity was low in sites with highest (>80%) Azolla coverage. Seventy-two (81.8%) of the anopheline and 90 (82.6%) culicine breeding sites were infested with Azolla. Water bodies infested with green Azolla were more productive than those covered by brown coloured Azolla substrates for both culicines (13%) and anophelines (8%). Of the 1537 field collected larvae that hatched to adult stage, 646 (42.03%) were Anopheles gambiae s.l., 42 (2.73%) were An. funestus and 769 (50.03%) were Culex quinquefasciatus. These findings suggest that the mosquito productivity is low when the Azolla coverage is high (>80%). The promotion of Azolla in mosquito control should take into consideration the degree of Azolla coverage.

Monitoring and evaluation of integrated disease surveillance and response in selected districts in Tanzania.

Integrated Disease Surveillance and Response (IDSR) is a strategy developed by the World Health Organization Regional Office for Africa in 1998. The Ministry of Health, Tanzania has adopted this strategy for strengthening communicable diseases surveillance in the country. In order to improve the effectiveness of the implementation of IDSR monitoring and evaluating the performance of the surveillance system, identifying areas that require strengthening and taking action is important. This paper presents the findings of baseline data collection for the period October-December 2003 in 12 districts representing eight regions of Tanzania. The districts involved were Mbulu, Babati, Dodoma Rural, Mpwapwa, Igunga, Tabora Urban, Mwanza Urban, Muleba, Nkasi, Sumbawanga Rural, Tunduru and Masasi. Results are grouped into three key areas: surveillance reporting, use of surveillance data and management of the IDSR system. In general, reporting systems are weak, both in terms of receiving all reports from all facilities in a timely manner, and in managing those reports at the district level. Routine analysis of surveillance data is not being done at facility or district levels, and districts do not monitor the performance of their surveillance system. There was also good communication and coordination with other sectors in terms of sharing information and resources. It is important that districts' capacity on IDSR is strengthened to enable them monitor and evaluate their own performance using established indicators.

Knowledge and health information communication in Tanzania

Objective: To explore and identify gaps in knowledge and information communication at all levels of health delivery system in Tanzania. Methods: In-depth interviews and twelve Focus Group Discussions were conducted to capture information on the community knowledge on different health problems and the health information communication process. Interviews and discussions were also held with primary schoolchildren; traditional healers; health facility workers and district health management team members. Documentary review and inventory of the available health education materials at community; health facility and district levels; was made. Results: Major community health and health-related problems included diseases (61.6); lack of potable water (36.5); frequent famine (26.9) and lack of health facility services (25.3). Malaria; HIV/AIDS and diarrhoeal diseases were the leading causes of morbidity and mortality. Most of the health communication packages covered communicable diseases and their prevention. Health care facility was the main (91.6) source of health information for most communities. Public meetings; radio and print materials were the most frequently used channels of health information communication. Major constraints in adopting health education messages included poverty; inappropriate health education; ignorance and local beliefs.Conclusion: This study has identified gaps in health knowledge and information communication in Tanzania. There is lack of adequate knowledge and information exchange capacities among the health providers and the ability to share that information with the targeted community. Moreover; although the information gets to the community; most of them are not able to utilize it properly because they lack the necessary background knowledge

Monitoring and evaluation of Integrated Disease Surveillance and Response in selected districts in Tanzania

Integrated Disease Surveillance and Response (IDSR) is a strategy developed by the World Health Organization. Regional Office for Africa in 1998. The Ministry of Health; Tanzania has adopted this strategy for strengthening communicable diseases surveillance in the country. In order to improve the effectiveness of the implementation of IDSRmonitoring and evaluating the performance of the surveillance system; identifying areas that require strengthening and taking action is important. This paper presents the findings of baseline data collection for the period October - December 2003 in 12 districts representing eight regions of Tanzania. The districts involved were Mbulu; Babati; odoma Rural; Mpwapwa; Igunga; Tabora Urban; Mwanza Urban; Muleba; Nkasi; Sumbawanga Rural; Tunduru and Masasi. Results are grouped into three key areas: surveillance reporting; use of surveillance data and management of the IDSR system. In general; reporting systems are weak; both in terms of receiving all reports from all acilities in a timely manner; and in managing those reports at the district level. Routine analysis of surveillance data is not being done at facility or district levels; and districts do not monitor the performance of their surveillance system. There was also good communication and coordination with other sectors in terms of sharing information and resources. It is important that districts' capacity on IDSR is strengthened to enable them monitor and evaluate their own performance using established indicators

Participatory involvement of farming communities and public sectors in determining malaria control strategies in Mvomero District, Tanzania.

Addressing the malaria-agriculture linkages requires a broad inter-disciplinary and integrated approach that involves farming communities and key public sectors. In this paper, we report results of participatory involvement of farming communities in determining malaria control strategies in Mvomero District, Tanzania. A seminar involving local government leaders, health and agricultural officials comprising of a total of 27 participants was held. Public meetings in villages of Komtonga, Mbogo, Mkindo, Dihombo and Luhindo followed this. Findings from a research on the impact of agricultural practices on malaria burden in the district were shared with local communities, public sector officials and other key stakeholders as a basis for a participatory discussion. The community and key stakeholders had an opportunity to critically examine the linkages between agricultural practices and malaria in their villages and to identify problems and propose practical solutions. Several factors were identified as bottlenecks in the implementation of malaria control in the area. Lack of community participation and decision making in malaria interventions was expressed as among the major constraints. This denied the community the opportunities of determining their health priorities and accessing knowledge needed to effectively implement malaria interventions. In conclusion, this paper emphasizes the importance of participatory approach that involves community and other key stakeholders in malaria control using an ecosystem approach. An interdisciplinary and integrated approach is needed to involve farmers and more than one sector in malaria control effort.

Community knowledge and information communication gaps on HIV/AIDS in Iringa Municipality; Tanzania

This study was carried out to determine community knowledge and information communication gaps on HIV/AIDS in Iringa Municipality; Tanzania. In-depth interviews and focus group discussions were used to collect data from both the community and health workers. Results showed that eighty-one percent of the respondents were knowledgeable of at least one mode of HIV/AIDS transmission. Sexual intercourse; sharing of sharp instruments; blood transfusion and mother to child transmission were known to be the most common ways on how HIV is transmitted. The community knowledge on the symptoms of AIDS was poor. The main sources of information on HIV/AIDS were health facilities; radio; televisions; religious leaders and relatives. The information covered in most of the health education programmes included prevention; treatment and care for AIDS patients. The understanding of HIV/AIDS messages was found to vary significantly between respondents with different levels of education and marital status. It was higher among those with at least a primary school education than in those without education. Singles and individuals with primary or post-primary education sought more new information than those who had no education at all. Among the respondents; 59.7reported to have difficulties in adopting and utilising HIV/AIDS educational messages. Singles had a better understanding of information provided than married respondents. However; the former had more difficulties in adopting and utilising health education information. Poor utilisation of the HIV/AIDS messages was attributed to culture; poverty; and illiteracy. The majority of the respondents; 370 (92.8) reported to often carry out discussions with their family members (including children) on HIV/AIDS. It is concluded that health education should identify community needs and address economic and socio-cultural barriers to facilitate education utilisation and behaviouralchanges required in HIV/AIDS prevention and control in Tanzania

Cholera outbreak in southern Tanzania: risk factors and patterns of transmission.

To identify risk factors and describe the pattern of spread of the 1997 cholera epidemic in a rural area (Ifakara) in southern Tanzania, we conducted a prospective hospital-based, matched case- control study, with analysis based on the first 180 cases and 360 matched controls. Bathing in the river, long distance to water source, and eating dried fish were significantly associated with risk for cholera. Toxigenic Vibrio cholerae O1, biotype El Tor, serotype Ogawa, was isolated in samples from Ifakara's main water source and patients' stools. DNA molecular analyses showed identical patterns for all isolates.

HIV incidence and HIV-associated mortality in a cohort of factory workers and their spouses in Tanzania, 1991 through 1996.

OBJECTIVE: To describe HIV incidence and HIV-associated mortality in a cohort of factory workers and their spouses with access to adequate sexually transmitted diseases (STD) treatment services and moderate exposure to sexual health interventions. METHODS: Follow-up visits at 4-month intervals and home follow-up of those who failed to keep appointments were used to estimate HIV incidence and mortality in a cohort of factory workers and their spouses in Mwanza, Tanzania, during 1991 to 1996. RESULTS: HIV prevalence at intake was 10.5% and 15.3% among 1,594 men and 880 women, respectively. HIV incidence was just over 1/100 person-years (PY) in 1,427 men and 1.9/100 PY in 745 women. The main risk factors were related to sexual behavior and clinical evidence of an STD, although only one seventh of those with HIV seroconversions had had an STD during the period following the second-from-last follow-up visit. HIV incidence among discordant couples was 5.0 and 8.3/100 PY for 41 men and 37 women, respectively. Mortality rates were 9.0 and 7.8/1,000 PY for men and women, respectively, and 65% of male and 60% of female deaths were attributable to HIV infection. CONCLUSIONS: In this factory population with good access to and use of STD treatment and with a moderate level of exposure to HIV prevention education, HIV incidence among men and women is still over 1/100 PY, which suggests a relatively high level of program effort is needed to lower incidence. More than half of all adult deaths were attributable to HIV, but greater increases in HIV-associated mortality are likely.

Dynamics of P. falciparum gametocytemia in symptomatic patients in an area of intense perennial transmission in Tanzania.

We investigated the dynamics of Plasmodium falciparum gametocytemia in symptomatic patients attending a local dispensary in the Kilombero district, Tanzania. Consenting individuals aged one and above, with varying asexual and sexual parasitemias were treated appropriately and asked to return weekly for 28 days. Gametocyte prevalence was highest on Day 7 of follow-up in all age groups (overall 30.5%). Multifactorial analysis showed that young age (chi2 = 18.4; P = 0.004), high asexual parasitemia on presentation (chi2 = 19.4; P = 0.0007) and gametocyte positivity on presentation (chi2 = 29.4; P = 0.001) were all significantly associated with the presence of gametocytes on Days 7 and 14 of follow-up. High presentation of asexual parasitemia alone was positively correlated with higher gametocyte densities on both days of follow-up (F4, 297 = 2.0; P = 0.049). Gametocyte incidence rates decreased significantly with age (chi2 = 7.6, P < 0.005). In summary, in this group of chloroquine-treated individuals, gametocyte prevalence and incidence rates decreased with age, while densities remained relatively constant.

Spread of HIV infection in a rural area of Tanzania.

OBJECTIVE: To assess the spread of HIV into rural areas. METHODS: Since 1994 a demographic surveillance system (with 5-monthly rounds) and open adult cohort study have been established in a rural ward in Tanzania. Two sero-surveys of all resident adults aged 15-44 and 15-46 years were conducted in 1994 1995 and 1996-1997 respectively. Qualitative data were collected on mobility, bars and commercial sex. RESULTS: Attendance of the two rounds of survey was 5820 (78%) and 6413 (80%) in 1994/1995 and 1996/1997 respectively. HIV prevalence increased from 5.8% to 6.6%. HIV incidence was 0.73 and 0.84 per 100 person years among men and women respectively. HIV incidence under the age of 20 years was low among both sexes. Striking differences in HIV prevalence and incidence were observed within the small geographic area studied: HIV prevalence in the trading center was twice that in the area surrounding the trading center (within 2 km) and three to four times that in the rural villages (within 8 km of the trading center). Aggregate level data showed significant differences between the trading center and nearby rural villages in terms of sexual behavior, commercial sex workers, mobility of the population, and alcohol use. CONCLUSION: This study documents the existence of very substantial HIV prevalence and incidence differences within a small geographic rural area. The rapid decrease in HIV prevalence within a small rural area emphasizes the importance of concentrating HIV prevention efforts on high transmission areas, such as trading centers, especially in resource-poor settings. Furthermore, this has considerable implications for monitoring the spread of HIV through sentinel sites, as such sites are typically located in high transmission areas.

Patterns of sexual behaviour in a rural population in north-western Tanzania.

The HIV epidemic in sub-Saharan Africa has been characterised by the predominance of heterosexual transmission. Patterns of sexual behaviour have been implicated in the spread of the epidemic, but few quantitative data are available on sexual behaviour in rural populations in Africa. This paper reports data from a survey of 1117 adults aged 15-54 years selected randomly from twelve rural communities in Mwanza Region, Tanzania. Sexual debut occurred early, 50% of women and 46% of men reporting first sex before age 16. On average, women married 1.8 years and men 6.1 years after their sexual debut. In women, age at sexual debut appears to have increased over time, in parallel with an increase in age at first marriage. Men were generally married later, to women around five to ten years younger than themselves. Marital dissolution and remarriage were common in both sexes. Reported numbers of sexual partners were compared with those recorded in a population survey in Britain. More men reported 10 or more lifetime partners, or three or more partners in the past year, in rural Mwanza (48% and 29%) than in Britain (24% and 6%). Women reported fewer partners, and results were broadly similar to British data. Casual sex during the past year was reported by 53% of the men and 15% of the women, but only 2% of men reported sexual contact with bar girls or commercial sex workers. Only 20% of men and 3% of women had ever used a condom. Interventions are needed to reduce the high levels of sexual partner change and casual sex, and low levels of condom use, recorded in this rural population. Targeting of interventions to traditional "core groups" may be of limited value in rural areas, and additional strategies are needed, focusing particularly on teenagers who are at high risk of HIV and other sexually transmitted diseases.

Sexual behaviour patterns and other risk factors for HIV infection in rural Tanzania: a case-control study.

OBJECTIVE: To examine the association between HIV infection and patterns of sexual behaviour and other risk factors in a rural Tanzanian population in a case-control study, nested within a randomized trial of improved sexually transmitted disease treatment. METHODS: All HIV-positive patients from the baseline survey of the randomized trial were eligible as cases. Cases (n = 338) and controls (a random sample of one in eight HIV-negative persons; n = 1078) were interviewed about risk factors for HIV infection using a structured questionnaire. RESULTS: A significantly higher HIV prevalence was found among men and women not currently employed in farming [men: odds ratio (OR), 2.08; women: OR, 3.65], women who had travelled (OR, 3.27), educated women (OR, 4.51), and widowed/ divorced people compared with those currently married (men: OR, 3.10; women: OR, 3.54). Two spouse-related factors were significantly associated with HIV, even after adjustment for the sexual behaviour of the index case: HIV was more prevalent in men with younger spouses (P = 0.020 for trend) and in women married to men currently employed in manual work, office work or business (OR, 2.20). In women only, blood transfusions were associated with a higher HIV prevalence (OR, 2.40), but only a small population attributable fraction (4%). There was an increased HIV prevalence associated with increasing numbers of injections. Reported number of lifetime sexual partners was significantly associated with HIV infection (women: OR, 7.33 if > or = 10 lifetime partners compared with < or = 1; men: OR, 4.35 for > or = 50 compared with < or = 1). After adjustment for confounders, male circumcision was associated with a lower HIV prevalence (OR, 0.65; P = 0.11). CONCLUSIONS: In these rural communities, many HIV infections occur through sexual transmission. Some people are at high risk of HIV infection through large numbers of sex partners, whereas some are at risk through their spouse or regular partner. The role of circumcision in HIV transmission is unclear. Commercial sex seems to play a negligible role in HIV transmission in these communities. Our results confirm marked heterogeneity in HIV risk, indicating the scope for risk reduction strategies.

PIP: In a baseline survey a cohort of 12,537 adults was enrolled, interviewed, and examined between November 1991 and December 1992 in the Mwanza Region of Tanzania using random cluster sampling. The study itself took place in May and June of 1993, and it consisted of 338 cases (149 men and 189 women) and 1078 controls (504 men and 574 women). The remainder of the analysis of men was restricted to the 149 cases and 394 controls 20-54 years old. The blood samples from consenting adults were tested for HIV antibodies by enzyme-linked immunosorbent assay (ELISA). A significantly higher HIV prevalence was found among men and women not currently employed in farming (men: odds ratio [OR] 2.08; women: OR 3.65), women who had traveled (OR 3.27), educated women (OR 4.51), and widowed/divorced people compared with those currently married (men: OR 3.10; women: OR 3.54). Two spouse-related factors were significantly associated with HIV even after adjustment for the sexual behavior of the index case: HIV was more prevalent in men with younger spouses (p = 0.020 for trend) and in women married to men currently employed in manual work, office work, or business (OR 2.20). In women only blood transfusions were associated with a 2-fold increased prevalence of HIV (OR 2.40), but only a small population-attributable fraction (4%). There was an increased HIV prevalence associated with increasing numbers of injections, even after adjustment for confounders. The reported number of lifetime sexual partners was significantly associated with HIV infection (women: OR 7.33 if or= 10 lifetime partners compared with or= 1; men: OR 4.35 for or= 50 compared with or= 1). After adjustment for confounders, male circumcision was associated with a lower HIV prevalence (OR 0.65; p = 0.11). Most HIV infections occurred through sexual transmission, although some were attributable to nonsterile injections. Since the large number of sexual partners was a major risk factor, intervention strategies should promote the reduction of partners and the use of condoms.

Changes in male sexual behaviour in response to the AIDS epidemic: evidence from a cohort study in urban Tanzania.

OBJECTIVE: To examine changes in sexual behaviour among men in urban Tanzania. DESIGN: An observational cohort study among factory workers during 1991-1994. METHODS: Data from five follow-up visits with structured questionnaire-guided interviews and biomedical data were analysed to examine trends in sexual behaviour and sexually transmitted disease/HIV among 752 men. In-depth interviews were conducted to evaluate the magnitude of reporting bias. RESULTS: During the 2 years of observation, the proportion of men with more than one sexual partner during the month preceding the interview declined from 22.3 to 12.2%. The proportion of men reporting casual sex partners during the last month was almost halved: from 9.8 to 5.2%. The decline in the reporting of extramarital partners was gradual and pronounced. There were only minor changes in reported condom use, notably an increase in use with casual partners, and no changes in coital frequency. Data from in-depth interviews confirmed that reduction in sexual partners was the predominant change. CONCLUSIONS: This study documents that, in response to the AIDS epidemic, changes in male sexual behaviour are taking place in urban areas in Africa. The predominant change among these men, who are predominantly married and aged over 25 years, is a reduction of the number of sexual partners, although condom use remains low.

PIP: During October 1991 to April 1994, health workers in Tanzania interviewed and conducted a physical examination of 752 men who had made at least 4 follow-up visits to the clinic at a large urban textile factory in Mwanza to examine trends in sexual behavior and sexually transmitted disease (STD)/HIV of factory workers and their spouses. Each man was followed for about 2 years. Researchers aimed to determine whether the intervention to reduce HIV transmission at the clinic had an impact on sex behavior. The intervention included free and effective treatment of STDs, a syphilis test at each visit, voluntary HIV counseling services, and health education activities (workshops, peer educators). The proportion of married men increased from 83.4% to 88.4% during the study period. Men were less likely to have more than 1 sexual partner in the previous month after 5 visits than before the first visit (12.2% vs. 22.3%; p 0.01 for trend). They were also less likely to have had casual partners during the previous month (5.2% vs. 9.8%; p 0.001 for trend). Married men were less likely to have extramarital relations (6.5% vs. 20.1% for regular non-cohabiting partner; p 0.01 and 2.7% vs. 8; p 0.001). Condom use in the previous month did not change significantly (2.5% vs. 3.1%; p = 0.377). It did increase significantly with a casual partner, however (7.6% vs. 27.3%; p = 0.002 for trend). Frequency of intercourse did not change. The HIV-incidence rate decreased considerably (1.77 vs. 0.66/100 person-years of observation for a rate ratio of 0.37). Multiple sex partners in the previous month was more common among men 20-29 years old or who consumed moderate or excessive amounts of alcohol than among those over age 40 or who consumed no alcohol. These findings suggest that even though sexual activity did not decline, it became more commonly with 1 partner and within marriage, especially among men 40 and older who did not drink alcohol. Condom use remained low, except with casual partners. ¿

Asymptomatic gonorrhoea and chlamydial infection in rural Tanzanian men.

OBJECTIVE: To measure the prevalence of urethritis due to Neisseria gonorrhoeae and Chlamydial infection trachomatis in rural Tanzanian men DESIGN: About 500 men aged 15-54 years were selected from each of 12 rural communities by random cluster sampling; interviewed concerning past or present symptoms of sexually transmitted diseases; and asked to provide a first catch urine specimen, which was tested for pyuria with a leucocyte esterase dipstick test. Subjects with symptoms or with a positive result on testing were examined, and urethral swabs were taken for detection of N gonorrhoeae by gram stain and of C trachomatis by antigen detection immunoassay. SETTING: Mwanza region, north western Tanzania. SUBJECTS: 5876 men aged 15-54 years. MAIN OUTCOME MEASURES: Prevalence of urethral symptoms, observed urethral discharge, pyuria, urethritis ( > 4 pus cells per high power field on urethral smear), N gonorrhoeae infection (intracellular gram negative diplococci), and C trachomatis infection (IDEIA antigen detection assay). RESULTS: 1618 (28%) subjects reported ever having a urethral discharge. Current discharge was reported by 149 (2.5%) and observed on examination in 207 (3.5%). Gonorrhoea was found in 128 subjects (2.2%) and chlamydial infection in 39 (0.7%). Only 24 of 158 infected subjects complained of urethral discharge at the time of interview (15%). CONCLUSION: Infection with N gonorrhoeae and C trachomatis is commonly asymptomatic among men in this rural African population. This has important implications for the design of control programmes for sexually transmitted disease.

A community trial of the impact of improved sexually transmitted disease treatment on the HIV epidemic in rural Tanzania: 2. Baseline survey results.

OBJECTIVES: To determine baseline HIV prevalence in a trial of improved sexually transmitted disease (STD) treatment, and to investigate risk factors for HIV. To assess comparability of intervention and comparison communities with respect to HIV/STD prevalence and risk factors. To assess adequacy of sample size. SETTING: Twelve communities in Mwanza Region, Tanzania: one matched pair of roadside communities, four pairs of rural communities, and one pair of island communities. One community from each pair was randomly allocated to receive the STD intervention following the baseline survey. METHODS: Approximately 1000 adults aged 15-54 years were randomly sampled from each community. Subjects were interviewed, and HIV and syphilis serology performed. Men with a positive leucocyte esterase dipstick test on urine, or reporting a current STD, were tested for urethral infections. RESULTS: A total of 12,534 adults were enrolled. Baseline HIV prevalences were 7.7% (roadside), 3.8% (rural) and 1.8% (islands). Associations were observed with marital status, injections, education, travel, history of STD and syphilis serology. Prevalence was higher in circumcised men, but not significantly after adjusting for confounders. Intervention and comparison communities were similar in the prevalence of HIV (3.8 versus 4.4%), active syphilis (8.7 versus 8.2%), and most recorded risk factors. Within-pair variability in HIV prevalence was close to the value assumed for sample size calculations. CONCLUSIONS: The trial cohort was successfully established. Comparability of intervention and comparison communities at baseline was confirmed for most factors. Matching appears to have achieved a trial of adequate sample size. The apparent lack of a protective effect of male circumcision contrasts with other studies in Africa.

PIP: To measure the impact of a sexually transmitted disease (STD) treatment program on the incidence of human immunodeficiency virus (HIV) in Zimbabwe's Mwanza Region, a pre-intervention baseline survey was conducted. Included in the survey were approximately 1000 randomly selected adults from each of the six intervention communities (defined as the population served by a health center and its satellite dispensaries) and six matched comparison communities. Overall HIV seroprevalence was 4.1% (3.7% in men and 4.4% in women), with a range of 1.6-8.6% and no significant differences between intervention and control communities. Peak prevalences for both sexes were found in the 25-34 year age groups and in roadside communities. The following factors were associated with an increased likelihood of HIV infection: separation, divorce, or widowhood; multiple injections in the preceding year; educational achievement of at least Standard 4; travel out of the district in the prior year; history of genital ulcers or discharge; and past or present infection with syphilis. HIV prevalence was significantly higher in circumcised men, but not when adjustment was made for other risk factors. Syphilis prevalence ranged from a low of 4.2% in island communities to a high of 11.1% in roadside communities. The baseline survey indicates that intervention and control populations are generally comparable, and that the goal of locating a study area with a relatively low incidence of HIV and high rates of other STDs has been achieved.

HIV-1 incidence and HIV-1 associated mortality in a cohort of urban factory workers in Tanzania.

OBJECTIVE: To determine HIV-1 incidence and HIV-1 associated mortality in a prospective cohort study. To determine whether the cohort is suitable for studies aiming to determine the impact of interventions on HIV-1 incidence. METHODS: The study population was a cohort of 1772 urban factory workers (1478 men and 294 women) in northwest Tanzania. The study took place from October 1991 to September 1993. Outcome measures were HIV-1 seroconversion and death. RESULTS: HIV-1 incidence was 1.2 (95% CI 0.7-2.0) per 100 person-years (pyr). Crude annual mortality was 4.9 per 100 pyr in those with and 0.3 in those without HIV-1 infection, giving an age and sex adjusted mortality ratio of 12.9 (95% CI 5.4-30.7). Of all deaths, 62% were attributable to HIV-1 infection. CONCLUSION: HIV-1 infection was a major public health problem, being the major cause of death in this adult population. At an HIV-1 incidence of 1.2 per 100 pyr, a large cohort size would be required to evaluate the impact of interventions on HIV-1 incidence.

PIP: The objectives were to determine HIV-1 incidence and HIV-1 associated mortality in a prospective cohort study and to determine whether the cohort is suitable for studies attempting to determine the impact of interventions on HIV-1 incidence. The study population was a cohort of 2038 urban factory workers in northwest Tanzania of whom 1772 workers (1478 men or 87% and 294 women or 89%) had enrolled in the study during October 1991 to September 1993. 471 (27%) of the total study population were lost to follow-up by the end of the study period. Outcome measures were HIV-1 seroconversion and death. At intake, 153 of 1478 (10.4%) men and 52 of 294 (17.7%) women were infected with HIV-1. In the study period, 17 seroconversions took place in 1365.9 person years of follow-up giving an HIV-1 incidence rate of 1.2/100 person-years of follow-up. No association was found between seroconversion and age or sex. The crude annual mortality rate was 4.9/100 person-years in those with and 0.3/100 person-years in those without HIV-1 infection, giving an age- and sex-adjusted mortality ratio of 12.9. The age- and sex-adjusted population attributable risk was 0.5/100 person-years, and of all deaths, 62% were attributable to HIV-1 infection. Of the 14 HIV-1 infected people who died, 9 met the criteria of the 1987 revised Centers for Disease Control/World Health Organization AIDS case definition: one had cryptococcal meningitis and eight HIV wasting syndrome. Two others had had weight loss and fever, but the evidence was inadequate to make or reject the diagnosis of AIDS. The remaining three without an AIDS diagnosis had pulmonary tuberculosis, diarrhea, and pyomyositis, respectively. HIV-1 infection was a major cause of death in this adult population. At an HIV-1 incidence of 1.2/100 person-years, a large cohort size would be required to evaluate the impact of interventions on HIV-1 incidence.

Impact of improved treatment of sexually transmitted diseases on HIV infection in rural Tanzania: randomised controlled trial.

A randomised trial was done to evaluate the impact of improved sexually transmitted disease (STD) case management at primary health care level on the incidence of HIV infection in the rural Mwanza region of Tanzania. HIV incidence was compared in six intervention communities and six pair-matched comparison communities. A random cohort of about 1000 adults aged 15-54 years from each community was surveyed at baseline and at follow-up 2 years later. Intervention consisted of establishment of an STD reference clinic, staff training, regular supply of drugs, regular supervisory visits to health facilities, and health education about STDs. 12,537 individuals were recruited. Baseline HIV prevalences were 3.8% and 4.4% in the intervention and comparison communities, respectively. At follow-up, 8845 (71%) of the cohort were seen. Of those initially seronegative, the proportions seroconverting over 2 years were 48 of 4149 (1.2%) in the intervention communities and 82 of 4400 (1.9%) in the comparison communities. HIV incidence was consistently lower in the intervention communities in all six matched pairs. Allowing for the community-randomised design and the effects of confounding factors, the estimated risk ratio was 0.58 (95% CI 0.42-0.79, p = 0.007). No change in reported sexual behaviour was observed in either group. We conclude that improved STD treatment reduced HIV incidence by about 40% in this rural population. This is the first randomised trial to demonstrate an impact of a preventive intervention on HIV incidence in a general population.

Risk assessment and other screening options for gonorrhoea and chlamydial infections in women attending rural Tanzanian antenatal clinics.

Sexually transmitted diseases (STDs) are a major cause of morbidity and mortality in developing countries and may play a key role in enhancing the heterosexual transmission of human immunodeficiency virus (HIV). Treatment of STDs is one of the most cost-effective of all health interventions in developing countries; however, STDs among women in rural populations have received little attention. In this study, we report that prevalences of STDs among 964 women attending antenatal clinics in a rural area of the United Republic of Tanzania. A total of 378 (39%) of these women were infected with at least one STD pathogen, 97 (10%) had syphilis, and 81 (8%) has Neisseria gonorrhoeae (NG) and/or Chlamydia trachomatis (CT) infection. The recommended syndromic approach to screening for NG/CT infection, based on reported genital symptoms, had a low sensitivity (43%) and failed to discriminate between infected and uninfected women. A risk score approach that we developed, based on sociodemographic and other factors associated with NG/CT infection, had a higher sensitivity and lower cost per true case treated than other approaches, although its positive predictive value was only about 20%.

PIP: During 1992-1993 in 12 rural health centers in Mwanza region, Tanzania, a baseline survey was conducted of 964 women attending a prenatal clinic to determine the prevalence of sexually transmitted diseases (STDs) and to evaluate various screening methods to identify those infected with Neisseria gonorrhoeae and Chlamydia trachomatis. Only 2.7% had ever used condoms. 66% had symptoms (vaginal discharge, genital itching, lower abdominal pain, painful or difficult urination, difficult or painful intercourse) associated with genital tract infection. 37% had abnormal vaginal discharge. 39% had a laboratory-confirmed STD. 49% had a reproductive tract infection. 10.1% had syphilis. 8.4% had gonorrhea and/or chlamydia. Sociodemographic factors associated with gonorrhea/chlamydia included age less than 25 (odds ratio [OR] = 2.2), unmarried status (OR = 3.2;), polygamous marriage (OR = 2.3), last child born more than 5 years earlier (OR = 3.2), and more than 1 sexual partner during the last year (OR = 1.7). When the researchers adjusted for these factors, the only signs or symptoms associated with gonorrhea/chlamydia were painful intercourse (OR = 2.1; p 0.02) and cervical discharge (OR = 3.2; p 0.06). The syndromic approach (based on vaginal discharge and/or genital itching and other symptoms related to the genital tract but not necessarily indicative of gonorrhea/chlamydia in pregnancy) had a higher sensitivity than the recommended syndromic approach based only on vaginal discharge and/or genital itching (72% vs. 43%). The risk score approach based on sociodemographic and other factors associated with gonorrhea/chlamydia infection had a higher sensitivity and lower cost/true case treated than other approaches. Yet, its positive predictive value was no greater than about 20%. A combination of case management using the World Health Organization syndromic approach for women with self-recognized genital infections together with screening for gonorrhea/chlamydia using a score-driven approach may be the most cost-effective approach to diagnosing and treating STDs.