Lingual palpation for porcine cysticercosis: a rapid epidemiological tool for estimating prevalence and community risk in Africa.

OBJECTIVE: To assess the association between the prevalence of tongue cyst-positive and antigen-positive pigs across different settings in Africa, to evaluate whether examining pigs for cysts could be used as a rapid surveillance tool for identifying geographical areas with a higher probability of high transmission of cysticercosis. METHODS: Published data were collated from 26 study sites across Africa that reported the prevalence of porcine cysticercosis by both lingual and serological examinations. The study sites were located in 10 countries across Africa. RESULTS: Seroprevalence rates ranged from 4% to 41%. Despite the varied study sites, the relationship between the two variables was highly consistent and suggests identification of tongue cysts may be useful for cysticercosis surveillance. We found that all areas with more than 10% of pigs having cysts in their tongues had at least 30% seroprevalence (PPV of 100%), although this cut-off is less reliable at predicting that an area is of low transmission (NPV of 84%). CONCLUSION: Assessing the prevalence of tongue cyst-positive pigs is a potential rapid epidemiological tool for identifying areas at high risk of cysticercosis, although further refinement and validation is required using standardised data sets.

The cost of not treating bednets.

For centuries, bednets have been used as a physical barrier against biting insects. Recent epidemiological investigations into their protective effects against malaria were quickly overtaken by studies focusing on the benefits of impregnating bednets with insecticide. The operational problems encountered in re-treating bednets with insecticide are often cited as an impediment to wide-scale implementation. The evidence for a protective effect of untreated nets against malaria is presented here alongside an analysis of how well untreated nets would need to work in order to compete with treated nets within a cost-effectiveness framework.

Updating the DALYs for diarrhoeal disease.

Estimates of global disease burden remain high on the international research and policy agenda as a forum for ranking health priorities. Within this, the quality of life or years lived with varying degrees of disability has been recognized as an important outcome that should be considered alongside estimates of mortality. Recent studies into the long-term consequences of diarrhoeal diseases on physical and mental development suggest that the disability adjusted life year calculations for these conditions could require updating.

The management of fevers in Kenyan children and adults in an area of seasonal malaria transmission.

This study investigates the source, timing and types of treatment for fevers across all ages in a low malaria-transmission area of Kenya. The period prevalence for fever, and subsequent treatment seeking behaviour, was similar across all ages. The use of the informal retail sector was common (47% of first actions), though most visits to shops and chemists (77%) resulted in treatment with an antipyretic not an antimalarial. The major source of the first line recommended drug, sulfadoxine-pyrimethamine (SP), was at the formal health sector, and 32% of fevers made at least one visit to a health care facility. Although only 7% of fevers received SP within 24 hours of fever onset, 27% ultimately received treatment with this antimalaria. It is estimated that of the total amount of SP consumed in this population, only 20% is administered to children less than 5 years old. In this area of Kenya disease risks decline with increasing age, however, adult populations consume over 40% of prescribed or purchased anti-malarial drugs. In light of the proposed new, more costly anti-malarial drug combinations these findings have major implications for the effective allocation of limited financial resources at household and government levels.

Impact of malaria during pregnancy on low birth weight in sub-Saharan Africa.

Malaria during pregnancy can result in low birth weight (LBW), an important risk factor for infant mortality. This article reviews the pathological effects of malaria during pregnancy and the implications for the newborn's development and survival. Empirical data from throughout Africa on associations between placental malaria and birth weight outcome, birth weight outcome and infant mortality, and the rates of LBW in areas with various levels of malaria transmission are evaluated to assess the increased risks of LBW and infant mortality associated with malaria. It is estimated that in areas where malaria is endemic, around 19% of infant LBWs are due to malaria and 6% of infant deaths are due to LBW caused by malaria. These estimates imply that around 100,000 infant deaths each year could be due to LBW caused by malaria during pregnancy in areas of malaria endemicity in Africa.

A cost analysis of the employer-based bednet programme in Coastal and Western Kenya.

Malaria remains a major health problem in Africa. One preventative strategy currently advocated is the use of bednets, preferably treated with insecticide. Many approaches to bednet delivery have been adopted in Kenya, including an employer-based malaria control strategy (EBMC). The cost and sustainability of this approach have not previously been assessed. This paper presents the financial cost (cash expenditure) of the EBMC programme implemented in the Coastal and Western regions of Kenya by the African Medical and Research Foundation (AMREF) between April 1998 and February 2002. Getting a bednet and insecticide to an employee was estimated to cost the provider US$15.8. This could be reduced by US$0.5 if the remaining stocks were liquidated and by an additional US$1.3 if the salvage of capital items is considered. The venture of distributing bednets to employees through the programme proved lucrative to organized community groups (OCGs), for they made between 24 and 29% gross profit from the nets they sold. Consequently, OCGs in nine of the 13 companies involved had retained enough funds from which they could buy and sell bednets without further donor financial support, and this portrays some elements of a sustainable supply system.

Too poor to pay: charging for insecticide-treated bednets in highland Kenya.

WHO has proposed malaria control as a means to alleviate poverty. One of its targets includes a 30-fold increase in insecticide-treated nets (ITNs) in the next 5 years. How this service will be financed remains unclear. In July 2000, 390 homesteads in rural highland Kenya were interviewed on their willingness to pay for ITNs. The costs to a household of protecting themselves with ITNs were compared with current household expenditure. Homesteads expressed a willingness to pay for ITNs, but the amounts offered were not sufficient to cover the costs of providing this service without donor support to meet the difference. Furthermore, as most household expenditure was allocated to basic needs these interventions were 'unaffordable'. The cost of protecting a household with ITNs would be equivalent to sending three children to primary school for a year. The aspiration by poor rural homesteads to protect themselves with ITNs is not compatible with their ability to pay. One option to have an immediate equitable impact on ITN coverage and break the cycle between malaria and poverty is to provide this service free of charge.

Free bednets to pregnant women through antenatal clinics in Kenya: a cheap, simple and equitable approach to delivery.

Kenya's National Malaria Strategy states that insecticide-treated nets (ITNs) would be considered as a free service to pregnant women assuming sufficient financial commitment from donors. In 2001, United Nation's Children's Fund (UNICEF) and the Government of Kenya brokered support to procure and distribute nets and K-O TABs (deltamethrin) to 70 000 pregnant women in 35 districts throughout Kenya around Africa Malaria Day. This intervention represented the single largest operational distribution of ITN services in Kenya to date, and this study evaluates its success, limitations and costs. The tracking process from the central level through to antenatal clinic (ANC) facilities suggests that of the 70 000 nets procured, 37 206 nets (53%) had been distributed to pregnant women throughout the country within 12 weeks. One-fifth of the nets procured (14 117) had gone out to individuals other than pregnant women, most of these at the request of the district teams, with only 2870 nets estimated to have gone astray at the ANC facilities. At 12 weeks, the remaining 18 677 nets were still in storage awaiting distribution, with more than two-thirds having reached the district, and nearly half already being held at ANC facilities. The cost of getting a net and K-O TAB to an ANC facility ready for distribution to a pregnant woman was US$ 3.81. Accounting for the 14 117 nets that had gone to other users, the cost for an ITN received by a pregnant woman was US$ 5.26. Delivering ITNs free to pregnant women through ANCs uses an existing system (with positive spin-offs of low delivery cost and simple logistics), is equitable (as it not only targets those who can afford it) and can have the added benefits of strengthening ANC service, delivery and use.

Malaria prevention in highland Kenya: indoor residual house-spraying vs. insecticide-treated bednets.

This study compares the effectiveness and cost-effectiveness of indoor residual house-spraying (IRS) and insecticide-treated bednets (ITNs) against infection with Plasmodium falciparum as part of malaria control in the highlands of western Kenya. Homesteads operationally targeted for IRS and ITNs during a district-based emergency response undertaken by an international relief agency were selected at random for evaluation. Five hundred and ninety homesteads were selected (200 with no vector control, 200 with IRS and 190 with ITNs). In July 2000, residents in these homesteads were randomly sampled according to three age-groups: 6 months-4 years, 5-15 years, and > 15 years for the presence of P. falciparum antigen (Pf HRP-2) using the rapid whole blood immunochromatographic test (ICT). The prevalence of P. falciparum infection amongst household members not protected by either IRS or ITN was 13%. Sleeping under a treated bednet reduced the risk of infection by 63% (58-68%) and sleeping in a room sprayed with insecticide reduced the risk by 75% (73-76%). The economic cost per infection case prevented by IRS was US$ 9 compared to US$ 29 for ITNs. This study suggests that IRS may be both more effective and cheaper than ITNs in communities subjected to low, seasonal risks of infection and as such should be considered as part of the control armamentarium for malaria prevention.

Clinical epidemiology of malaria in the highlands of western Kenya.

Malaria in the highlands of Kenya is traditionally regarded as unstable and limited by low temperature. Brief warm periods may facilitate malaria transmission and are therefore able to generate epidemic conditions in immunologically naive human populations living at high altitudes. The adult:child ratio (ACR) of malaria admissions is a simple tool we have used to assess the degree of functional immunity in the catchment population of a health facility. Examples of ACR are collected from inpatient admission data at facilities with a range of malaria endemicities in Kenya. Two decades of inpatient malaria admission data from three health facilities in a high-altitude area of western Kenya do not support the canonical view of unstable transmission. The malaria of the region is best described as seasonal and meso-endemic. We discuss the implications for malaria control options in the Kenyan highlands.

Defining and detecting malaria epidemics in the highlands of western Kenya.

Epidemic detection algorithms are being increasingly recommended for malaria surveillance in sub-Saharan Africa. We present the results of applying three simple epidemic detection techniques to routinely collected longitudinal pediatric malaria admissions data from three health facilities in the highlands of western Kenya in the late 1980s and 1990s. The algorithms tested were chosen because they could be feasibly implemented at the health facility level in sub-Saharan Africa. Assumptions of these techniques about the normal distribution of admissions data and the confidence intervals used to define normal years were also investigated. All techniques identified two "epidemic" years in one of the sites. The untransformed Cullen method with standard confidence intervals detected the two "epidemic" years in the remaining two sites but also triggered many false alarms. The performance of these methods is discussed and comments made about their appropriateness for the highlands of western Kenya.