The population biology and epidemiology of schistosome and geohelminth infections among schoolchildren in Tanzania

A study of helminth infections was undertaken among 3244 schoolchildren from 28 schools in Morogoro Rural District, Tanzania. Schistosoma haematobium was the most common infection, followed by hookworms, Ascaris lumbricoides, S. mansoni, and Trichuris trichiura. Infection prevalence of each species varied among schools and age groups, but not between sexes. There was no relationship between the prevalences of different infections among schools, except for a strong negative correlation between the prevalence of hookworm and S. mansoni infections. Within each age group, there was little excess overlap in the distribution of each infection; thus the number of multiple infections was low whereas the number of individuals harbouring at least one infection was relatively high. More children than expected carried infections of A. lumbricoides and S. mansoni, and the clustering effect increased with age. Only 2 schools had high overall infection prevalences of both geohelminths and schistosomes. Logistic regression analysis of morbidity and parasitological data indicated that individuals with multiple species infections were not at increased risk of morbidity (on a multiplicative scale) compared to individuals with single species infections. This was attributed in part to the low egg counts observed for each parasite species. The results implied little interaction between schistosome and geohelminth infections in the region, both in parasitological terms and in the context of their combined effects on health. Implications for the feasibility and benefits of combined control of geohelminths and schistosomes are discusse

Ultrasound scanning for detecting morbidity due to Schistosoma haematobium and its resolution following treatment with different doses of praziquantel

A study to assess the resolution of urinary tract morbidity due to Schistosoma haematobium was conducted on 2 cohorts of schoolchildren attending neighbouring schools in Kilombero District, southern Tanzania. Schoolchildren were screened for S. haematobium infection using the standard World Health Organization filtration technique and subsequently examined for urinary tract pathology using a portable 3·0 MHz sector scanner (Siemens Sonoline 1300). Treatment with praziquantel was given to all infected children. Children with observed urinary tract pathology received either 20 (n = 52) or 40 (n = 79) mg/kg body weight and were sonographically re-examined one, 2, 3 and 6 months following treatment. Geometric mean outputs of 21 and 19 eggs/ml of urine were detected in the 2 cohorts before treatment. Urinary tract pathology correlated positively with egg output (χ2, P = 0·02) and microhaematuria (P = 0·0001). Bladder (wall irregularities and polyps) and kidney (congestive changes) pathologies were found in 81% and 36%, respectively, of the group that received 20 mg/kg of praziquantel, and in 78% and 46% of the group that received 40 mg/kg. Six months after treatment, 90·4% and 88·0% parasitological cure rates were obtained using 20 or 40 mg praziquantel/kg body weight. The respective pathology clearances were 88% and 91%. 20 mg/kg of praziquantel was as effective with regard to cure rates and reversibility of morbidity as 40 mg/k

The use of morbidity questionnaires to identify communities with high prevalences of schistosome or geohelminth infections in Tanzania

Parasitic infections were investigated in Morogoro Rural District, Tanzania, between October 1992 and June 1993. A total of 4589 schoolchildren (aged 7-17 years) from 30 primary schools was screened for infection with Ascaris lumbricoides, Trichuris trichiura, hookworms (3456 children only), Schistosoma mansoni and S. haematobium. The children were also asked about their recent experiences of the following: diarrhoea, abdominal pain, blood in stool, perception of suffering from schistosomiasis, and worm infection and examined for spleen and liver enlargement. Among schools, there were correlations between the prevalence of S. mansoni infection and bloody stools, spleen enlargement and liver enlargement, and between S. haematobium infection and the presence of blood in urine. To exclude ecological explanations for the correlations, logistic regression was used to estimate the adjusted odds ratio (OR) for each infection and each sign or symptom. No sign or symptom was significantly associated with any geohelminth infection. Reported blood in stool was significantly associated with S. mansoni infection (OR = 1·62, P = 0·045). Reported blood in urine was significantly associated with S. haematobium infection (OR = 7·71, P < 0·001), as was reported blood in stool (OR = 11·52, P < 0·001), indicating that presence of blood in either form of excreta was related to the local term for schistosomiasis. These results support the possibility of using reported blood in stool as a means of rapid assessment for identifying communities with a high prevalence of S. mansoni infectio

Infection intensity-dependent accuracy of reagent strip for the diagnosis of Schistosoma haematobium and estimation of treatment prevalence thresholds

BACKGROUND: Reagent strip to detect microhematuria as a proxy for Schistosoma haematobium infections has been considered an alternative to urine filtration for individual diagnosis and community-based estimates of treatment needs for preventive chemotherapy. However, the diagnostic accuracy of reagent strip needs further investigation, particularly at low infection intensity levels. METHODS: We used existing data from a study conducted in Tanzania that employed urine filtration and reagent strip testing for S. haematobium in two villages, including a baseline and six follow-up surveys after praziquantel treatment representing a wide range of infection prevalence. We developed a Bayesian model linking individual S. haematobium egg count data based on urine filtration to reagent strip binary test results available on multiple days and estimated the relation between infection intensity and sensitivity of reagent strip. Furthermore, we simulated data from 3,000 hypothetical populations with varying mean infection intensity to infer on the relation between prevalence observed by urine filtration and the interpretation of reagent strip readings. PRINCIPAL FINDINGS: Reagent strip showed excellent sensitivity even for single measurement reaching 100% at around 15 eggs of S. haematobium per 10 ml of urine when traces on reagent strip were considered positive. The corresponding specificity was 97%. When traces were considered negative, the diagnostic accuracy of the reagent strip was equivalent to urine filtration data obtained on a single day. A 10% and 50% urine filtration prevalence based on a single day sampling corresponds to 11.2% and 48.6% prevalence by reagent strip, respectively, when traces were considered negative, and 17.6% and 57.7%, respectively, when traces were considered positive. CONCLUSIONS/SIGNIFICANCE: Trace results should be included in reagent strip readings when high sensitivity is required, but excluded when high specificity is needed. The observed prevalence of reagent strip results, when traces are considered negative, is a good proxy for prevalence estimates of S. haematobium infection by urine filtration on a single day

Malaria risk and access to prevention and treatment in the paddies of the Kilombero Valley, Tanzania

Background: The Kilombero Valley is a highly malaria-endemic agricultural area in south-eastern Tanzania. Seasonal flooding of the valley is favourable to malaria transmission. During the farming season, many households move to distant field sites (shamba in Swahili) in the fertile river floodplain for the cultivation of rice. In the shamba, people live for several months in temporary shelters, far from the nearest health services. This study assessed the impact of seasonal movements to remote fields on malaria risk and treatment-seeking behaviour. Methods: A longitudinal study followed approximately 100 randomly selected farming households over six months. Every household was visited monthly and whereabouts of household members, activities in the fields, fever cases and treatment seeking for recent fever episodes were recorded. Results: Fever incidence rates were lower in the shamba compared to the villages and moving to the shamba did not increase the risk of having a fever episode. Children aged 1-4 years, who usually spend a considerable amount of time in the shamba with their caretakers, were more likely to have a fever than adults (odds ratio = 4.47, 95 confidence interval 2.35-8.51). Protection with mosquito nets in the fields was extremely good (98 antimalarials was uncommon. Despite the long distances to health services, 55.8 health facility, while home-management was less common (37 17.4-50.5). Conclusion: Living in the shamba does not appear to result in a higher fever-risk. Mosquito nets usage and treatment of fever in health facilities reflect awareness of malaria. Inability to obtain drugs in the fields may contribute to less irrational use of drugs but may pose an additional burden on poor farming households. A comprehensive approach is needed to improve access to treatment while at the same time assuring rational use of medicines and protecting fragile livelihoods

Health status and quality of life among older adults in rural Tanzania

BACKGROUND\ud \ud Increasingly, human populations throughout the world are living longer and this trend is developing in sub-Saharan Africa. In developing African countries such as Tanzania, this demographic phenomenon is taking place against a background of poverty and poor health conditions. There has been limited research on how this process of ageing impacts upon the health of older people within such low-income settings.\ud \ud OBJECTIVE\ud \ud The objective of this study is to describe the impacts of ageing on the health status, quality of life and well-being of older people in a rural population of Tanzania.\ud \ud DESIGN\ud \ud A short version of the WHO Survey on Adult Health and Global Ageing questionnaire was used to collect information on the health status, quality of life and well-being of older adults living in Ifakara Health and Demographic Surveillance System, Tanzania, during early 2007. Questionnaires were administered through this framework to 8,206 people aged 50 and over.\ud \ud RESULTS\ud \ud Among people aged 50 and over, having good quality of life and health status was significantly associated with being male, married and not being among the oldest old. Functional ability assessment was associated with age, with people reporting more difficulty in performing routine activities as age increased, particularly among women. Reports of good quality of life and well-being decreased with increasing age. Women were significantly more likely to report poor quality of life (odds ratio 1.31; p<0.001, 95% CI 1.15-1.50).\ud \ud CONCLUSIONS\ud \ud Older people within this rural Tanzanian setting reported that the ageing process had significant impacts on their health status, quality of life and physical ability. Poor quality of life and well-being, and poor health status in older people were significantly associated with marital status, sex, age and level of education. The process of ageing in this setting is challenging and raises public health concerns

Data Resource Profile: The World Health Organization Study on global AGEing and adult health (SAGE)

Population ageing is rapidly becoming a global issue and will have a major impact on health policies and programmes. The World Health Organization's Study on global AGEing and adult health (SAGE) aims to address the gap in reliable data and scientific knowledge on ageing and health in low- and middle-income countries. SAGE is a longitudinal study with nationally representative samples of persons aged 50+ years in China, Ghana, India, Mexico, Russia and South Africa, with a smaller sample of adults aged 18-49 years in each country for comparisons. Instruments are compatible with other large high-income country longitudinal ageing studies. Wave 1 was conducted during 2007-2010 and included a total of 34 124 respondents aged 50+ and 8340 aged 18-49. In four countries, a subsample consisting of 8160 respondents participated in Wave 1 and the 2002/04 World Health Survey (referred to as SAGE Wave 0). Wave 2 data collection will start in 2012/13, following up all Wave 1 respondents. Wave 3 is planned for 2014/15. SAGE is committed to the public release of study instruments, protocols and meta- and micro-data: access is provided upon completion of a Users Agreement available through WHO's SAGE website (www.who.int/healthinfo/systems/sage) and WHO's archive using the National Data Archive application (http://apps.who.int/healthinfo/systems/surveydata

Obstacles to prompt and effective malaria treatment lead to low community-coverage in two rural districts of Tanzania

BACKGROUND\ud \ud Malaria is still a leading child killer in sub-Saharan Africa. Yet, access to prompt and effective malaria treatment, a mainstay of any malaria control strategy, is sub-optimal in many settings. Little is known about obstacles to treatment and community-effectiveness of case-management strategies. This research quantified treatment seeking behaviour and access to treatment in a highly endemic rural Tanzanian community. The aim was to provide a better understanding of obstacles to treatment access in order to develop practical and cost-effective interventions.\ud \ud METHODS\ud \ud We conducted community-based treatment-seeking surveys including 226 recent fever episodes in 2004 and 2005. The local Demographic Surveillance System provided additional household information. A census of drug retailers and health facilities provided data on availability and location of treatment sources.\ud \ud RESULTS\ud \ud After intensive health education, the biomedical concept of malaria has largely been adopted by the community. 87.5% (78.2-93.8) of the fever cases in children and 80.7% (68.1-90.0) in adults were treated with one of the recommended antimalarials (at the time SP, amodiaquine or quinine). However, only 22.5% (13.9-33.2) of the children and 10.5% (4.0-21.5) of the adults received prompt and appropriate antimalarial treatment. Health facility attendance increased the odds of receiving an antimalarial (OR = 7.7) but did not have an influence on correct dosage. The exemption system for under-fives in public health facilities was not functioning and drug expenditures for children were as high in health facilities as with private retailers.\ud \ud CONCLUSION\ud \ud A clear preference for modern medicine was reflected in the frequent use of antimalarials. Yet, quality of case-management was far from satisfactory as was the functioning of the exemption mechanism for the main risk group. Private drug retailers played a central role by complementing existing formal health services in delivering antimalarial treatment. Health system factors like these need to be tackled urgently in order to translate the high efficacy of newly introduced artemisinin-based combination therapy (ACT) into equitable community-effectiveness and health-impact