Biomedical subjects

Joanna A Schellenberg

Publications and source records attributed to Joanna A Schellenberg.

4 recordsLinked to original sources

PubMed2006

Quantifying behavioural interactions between humans and mosquitoes: evaluating the protective efficacy of insecticidal nets against malaria transmission in rural Tanzania.

BACKGROUND: African malaria vectors bite predominantly indoors at night so sleeping under an Insecticide-Treated Net (ITN) can greatly reduce malaria risk. Behavioural adaptation by mosquitoes to increasing ITN coverage could allow vector mosquitoes to bite outside of peak sleeping hours and undermine efficacy of this key malaria prevention measure. METHODS: High coverage with largely untreated nets has been achieved in the Kilombero Valley, southern Tanzania through social marketing programmes. Direct surveys of nightly biting activity by An. gambiae Giles were conducted in the area before (1997) and after (2004) implementation of ITN promotion. A novel analytical model was applied to estimate the effective protection provided by an ITN, based on published experimental hut trials combined with questionnaire surveys of human sleeping behaviour and recorded mosquito biting patterns. RESULTS: An. gambiae was predominantly endophagic and nocturnal in both surveys: Approximately 90% and 80% of exposure occurred indoors and during peak sleeping hours, respectively. ITNs consistently conferred >70% protection against exposure to malaria transmission for users relative to non-users. CONCLUSION: As ITN coverage increases, behavioural adaptation by mosquitoes remains a future possibility. The approach described allows comparison of mosquito biting patterns and ITN efficacy at multiple study sites and times. Initial results indicate ITNs remain highly effective and should remain a top-priority intervention. Combined with recently developed transmission models, this approach allows rapid, informative and cost-effective preliminary comparison of diverse control strategies in terms of protection against exposure before more costly and intensive clinical trials.

Animals↗

PubMed2004

Retail supply of malaria-related drugs in rural Tanzania: risks and opportunities.

OBJECTIVES: To characterize availability of fever and malaria medicines within the retail sector in rural Tanzania, assess the likely public health implications, and identify opportunities for policy interventions to increase the coverage of effective treatment. METHODS: A census of retailers selling drugs was undertaken in the areas under demographic surveillance in four Tanzanian districts, using a structured questionnaire. RESULTS: Drugs were stocked by two types of retailer: a large number of general retailers (n = 675) and a relatively small number of drug shops (n = 43). Almost all outlets stocked antipyretics/painkillers. One-third of general retailers stocking drugs had antimalarials, usually chloroquine alone. Almost all drug shops stocked antimalarials (98%): nearly all had chloroquine, 42% stocked quinine, 37% sulphadoxine-pyrimethamine and 30% amodiaquine. A large number of antimalarial brands were available. Population ratios indicate the relative accessibility of retail drug providers compared with health facilities. Drug shop staff generally travelled long distances to buy from drugs wholesalers or pharmacies. General retailers bought mainly from local general wholesalers, with a few general wholesalers accounting for a high proportion of all sources cited. CONCLUSIONS: Drugs were widely available from a large number of retail outlets. Potential negative implications include provision of ineffective drugs, confusion over brand names, uncontrolled use of antimalarials, and the availability of components of potential combination therapy regimens as monotherapies. On the other hand, this active and highly accessible retail market provides opportunities for improving the coverage of effective antimalarial treatment. Interventions targeted at all drug retailers are likely to be costly to deliver and difficult to sustain, but two promising points for targeted intervention are drug shops and selected general wholesalers. Retail quality may also be improved through consumer education, and modification of the chemical quality, packaging and price of products entering the retail distribution chain.

Analgesics, Non-Narcotic↗

PubMed2004

Mosquito nets and the poor: can social marketing redress inequities in access?

Treated mosquito nets are a practical malaria control tool. However, implementation of efficient delivery mechanisms remains a challenge. We investigated whether social marketing of treated mosquito nets results in decreased equity in rural Tanzania, through household surveys before the start of a social marketing programme and 3 years later. About 12,000 household heads were asked about ownership of nets and other assets including a tin roof, radio, or bicycle. A socio-economic status score was developed for each household. Net ownership was calculated for households in each quintile of this score, from poorest to least poor. In 1997, about 20% of the poorest households and over 60% of the least poor households owned a mosquito net. Three years later, more than half of the poorest households owned a net, as did over 90% of the least poor: the ratio of net ownership among the poorest to least poor increased from 0.3 in 1997 to 0.6 in 2000. Social marketing in the presence of an active private sector for nets was associated with increased equity.

Animals↗

PubMedDate not supplied

Gaps in policy-relevant information on burden of disease in children: a systematic review.

BACKGROUND: Valid information about cause-specific child mortality and morbidity is an essential foundation for national and international health policy. We undertook a systematic review to investigate the geographical dispersion of and time trends in publication for policy-relevant information about children's health and to assess associations between the availability of reliable data and poverty. METHODS: We identified data available on Jan 1, 2001, and published since 1980, for the major causes of morbidity and mortality in young children. Studies with relevant data were assessed against a set of inclusion criteria to identify those likely to provide unbiased estimates of the burden of childhood disease in the community. FINDINGS: Only 308 information units from more than 17,000 papers identified were regarded as possible unbiased sources for estimates of childhood disease burden. The geographical distribution of these information units revealed a pattern of small well-researched populations surrounded by large areas with little available information. No reliable population-based data were identified from many of the world's poorest countries, which account for about a third of all deaths of children worldwide. The number of new studies diminished over the last 10 years investigated. INTERPRETATION: The number of population-based studies yielding estimates of burden of childhood disease from less developed countries was low. The decreasing trend over time suggests reductions in research investment in this sphere. Data are especially sparse from the world's least developed countries with the highest child mortality. Guidelines are needed for the conduct of burden-of-disease studies together with an international research policy that gives increased emphasis to global equity and coverage so that knowledge can be generated from all regions of the world.

Acute Disease↗