Wind direction and proximity to larval sites determines malaria risk in Kilifi District in Kenya

Studies of the fine-scale spatial epidemiology of malaria consistently identify malaria hotspots, comprising clusters of homesteads at high transmission intensity. These hotspots sustain transmission, and may be targeted by malaria-control programmes. Here we describe the spatial relationship between the location of Anopheles larval sites and human malaria infection in a cohort study of 642 children, aged 1–10-years-old. Our data suggest that proximity to larval sites predict human malaria infection, when homesteads are upwind of larval sites, but not when homesteads are downwind of larval sites. We conclude that following oviposition, female Anophelines fly upwind in search for human hosts and, thus, malaria transmission may be disrupted by targeting vector larval sites in close proximity, and downwind to malaria hotspots

Design and descriptive epidemiology of the Infectious Diseases of East African Livestock (IDEAL) project, a longitudinal calf cohort study in western Kenya

BACKGROUND: There is a widely recognised lack of baseline epidemiological data on the dynamics and impacts of infectious cattle diseases in east Africa. The Infectious Diseases of East African Livestock (IDEAL) project is an epidemiological study of cattle health in western Kenya with the aim of providing baseline epidemiological data, investigating the impact of different infections on key responses such as growth, mortality and morbidity, the additive and/or multiplicative effects of co-infections, and the influence of management and genetic factors. A longitudinal cohort study of newborn calves was conducted in western Kenya between 2007-2009. Calves were randomly selected from all those reported in a 2 stage clustered sampling strategy. Calves were recruited between 3 and 7 days old. A team of veterinarians and animal health assistants carried out 5-weekly, clinical and postmortem visits. Blood and tissue samples were collected in association with all visits and screened using a range of laboratory based diagnostic methods for over 100 different pathogens or infectious exposures. RESULTS: The study followed the 548 calves over the first 51 weeks of life or until death and when they were reported clinically ill. The cohort experienced a high all cause mortality rate of 16% with at least 13% of these due to infectious diseases. Only 307 (6%) of routine visits were classified as clinical episodes, with a further 216 reported by farmers. 54% of calves reached one year without a reported clinical episode. Mortality was mainly to east coast fever, haemonchosis, and heartwater. Over 50 pathogens were detected in this population with exposure to a further 6 viruses and bacteria. CONCLUSION: The IDEAL study has demonstrated that it is possible to mount population based longitudinal animal studies. The results quantify for the first time in an animal population the high diversity of pathogens a population may have to deal with and the levels of co-infections with key pathogens such as Theileria parva. This study highlights the need to develop new systems based approaches to study pathogens in their natural settings to understand the impacts of co-infections on clinical outcomes and to develop new evidence based interventions that are relevant

Sequelae due to bacterial meningitis among African children: a systematic literature review

<p>Abstract</p> <p>Background</p> <p>African children have some of the highest rates of bacterial meningitis in the world. Bacterial meningitis in Africa is associated with high case fatality and frequent neuropsychological sequelae. The objective of this study is to present a comprehensive review of data on bacterial meningitis sequelae in children from the African continent.</p> <p>Methods</p> <p>We conducted a systematic literature search to identify studies from Africa focusing on children aged between 1 month to 15 years with laboratory-confirmed bacterial meningitis. We extracted data on neuropsychological sequelae (hearing loss, vision loss, cognitive delay, speech/language disorder, behavioural problems, motor delay/impairment, and seizures) and mortality, by pathogen.</p> <p>Results</p> <p>A total of 37 articles were included in the final analysis representing 21 African countries and 6,029 children with confirmed meningitis. In these studies, nearly one fifth of bacterial meningitis survivors experienced in-hospital sequelae (median = 18%, interquartile range (IQR) = 13% to 27%). About a quarter of children surviving pneumococcal meningitis and <it>Haemophilus influenzae </it>type b (Hib) meningitis had neuropsychological sequelae by the time of hospital discharge, a risk higher than in meningococcal meningitis cases (median = 7%). The highest in-hospital case fatality ratios observed were for pneumococcal meningitis (median = 35%) and Hib meningitis (median = 25%) compared to meningococcal meningitis (median = 4%). The 10 post-discharge studies of children surviving bacterial meningitis were of varying quality. In these studies, 10% of children followed-up post discharge died (range = 0% to 18%) and a quarter of survivors had neuropsychological sequelae (range = 3% to 47%) during an average follow-up period of 3 to 60 months.</p> <p>Conclusion</p> <p>Bacterial meningitis in Africa is associated with high mortality and risk of neuropsychological sequelae. Pneumococcal and Hib meningitis kill approximately one third of affected children and cause clinically evident sequelae in a quarter of survivors prior to hospital discharge. The three leading causes of bacterial meningitis are vaccine preventable, and routine use of conjugate vaccines could provide substantial health and economic benefits through the prevention of childhood meningitis cases, deaths and disability.</p

The epidemiological landscape of anemia in women of reproductive age in sub-Saharan Africa

The role of geographical disparities of health-related risk factors with anemia are poorly documented for women of reproductive age in sub-Saharan Africa (SSA). We aimed to determine the contribution of potential factors and to identify areas at higher risk of anemia for women in reproductive age in SSA. Our study population comprised 27 nationally representative samples of women of reproductive age (15–49) who were enrolled in the Demographic and Health Surveys and conducted between 2010 and 2019 in SSA. Overall, we found a positive association between being anemic and the ecological exposure to malaria incidence [adjusted odds ratio (AOR) = 1.02, 95% confidence interval (CI) 1.02–1.02], and HIV prevalence (AOR = 1.01, CI 1.01–1.02). Women currently pregnant or under deworming medication for the last birth had 31% (AOR = 1.31, CI 1.24–1.39) and 5% (AOR = 1.05, CI 1.01–1.10) higher odds of having anemia, respectively. Similarly, women age 25–34 years old with low education, low income and living in urban settings had higher odds of having anemia. In addition, underweight women had 23% higher odds of suffering anemia (AOR = 1.23, CI 1.15–1.31). Females with low levels of education and wealth index were consistently associated with anemia across SSA. Spatial distribution shows increased risk of anemia in Central and Western Africa. Knowledge about the contribution of known major drivers and the spatial distribution of anemia risk can mitigate operational constraints and help to design geographically targeted intervention programs in SSA

Development of cultural management of Russian wheat aphid (Diuraphis noxia Kurdjumov) damage on wheat crop

Wheat is the second most important crop in Kenya after maize and it is becoming an important source of food for humans and livestock. Kenya’s annual domestic demand stands at 900,000 MT against production of 300,000 MT, hence the need for enhanced efforts in generation and dissemination of production technologies. Despite its importance, wheat production in Kenya has been on a declining trend in the last 10 years. Its production has stagnated due to high cost of production. Among the main costs that constrain wheat production is the cost of chemicals for both insect pests and foliar diseases. The main insect pest in wheat growing areas of Kenya is the Russian wheat aphid (RWA). It can cause grain yield losses of up to 90% in the farmers’ fields if uncontrolled. Currently, the main RWA control strategy is use of chemical seed dressers and sprays that are expensive and possibly harmful to the environment. A field study was conducted in 2011 and 2012 crop seasons in Njoro, Kenya to test and develop environment friendly agronomic/cultural practices in the management of (RWA ) to reduce/avoid use of chemicals in wheat production. Six promising wheat lines, K. Tai, K. Sunbird, K. Korongo, K. Hawk and K. Kingbird selected from national performance trial (NPT) and three commercial varieties, Robin K. Eagle and NBWII were sown in RCBD in spilt plot arrangement. Main plots consisted of wheat sown at three seeding rates 75, 100 and 125 kg/ha. Sub plots consisted of nitrogen applied to wheat at crop tillering stage (GS 22) through the soil at three rates, 75, 100 and 130 kg N ha-1. No chemical control of the RWA was done but weeds and foliar diseases were controlled through chemical sprays. The results obtained showed that variety K. Korongo gave the lowest aphid count of 2.8 aphids/3 plants, followed by Robin (2.9 aphids) and K. Hawk (3.1). Robin gave the highest grain yield 5307.0 kg ha-1, followed by K. Korongo (2509.6 kg ha-1) and K. Hawk (2430.4 kg ha-1). Nitrogen at 100 kg N ha-1 and seeding at 100 kg ha-1 appeared the best rates. The results show that it may be possible to combine optimal N rates with optimal seed rates in the management of RWA in wheat production