Risk Factors for Mortality in Children Hospitalized With Severe Malaria in Northern Zambia: A Retrospective Case-Control Study

Malaria remains a public health crisis in areas where it has resisted control efforts. In Nchelenge District, a high-transmission area in northern Zambia, malaria accounts for more than one-third of pediatric hospitalizations and nearly one-half of hospital deaths in children. To identify risk factors for death due to malaria, we conducted a retrospective, time-matched case-control study of 126 children hospitalized with malaria who died (cases) and 126 children who survived (controls). There were no differences in age, gender, hemoglobin concentration, or prevalence of severe anemia between cases and controls. Children who died were more likely to come from villages located at greater distances from the hospital than children who survived (median 13.5 versus 3.2 km). Each additional kilometer of distance from the hospital increased the odds of death by 4% (odds ratio 1.04, 95% confidence interval 1.01–1.07, P \u3c 0.01). Extent of anemia and admission during periods when blood was unavailable for transfusion were associated with early death (P £ 0.03). Delays in initiation of treatment of severe malaria contribute to the increased odds of death in children referred from more distant health centers, and might be mitigated by transportation improvements, capacity at rural health posts to administer treatment before transfer, hospital triage systems that minimize time to treatment, and reliable blood product stores at referral hospitals

Risk factors for household vector abundance using indoor CDC light traps in a high malaria transmission area of Northern Zambia

Malaria transmission is dependent on the density and distribution of mosquito vectors, but drivers of vector abundance have not been adequately studied across a range of transmission settings. To inform intervention strategies for high-burden areas, further investigation is needed to identify predictors of vector abundance. Active household (HH) surveillance was conducted in Nchelenge district, Luapula Province, northern Zambia, a high-transmission setting with limited impact ofmalaria control. Between April 2012 and July 2017,mosquitoeswere collected indoors during HH visits using CDC light traps. Demographic, environmental, and climatological correlates of vector abundance were identified using log-binomial regressionmodels with robust standard errors. The primarymalaria vectors in this setting were Anopheles funestus sensu stricto (s.s.) andAnopheles gambiae s.s. Anopheles funestus predominated inboth seasons, with a peak in the dry season. Anopheles gambiae peaked at lower numbers in the rainy season. Environmental, climatic, and demographic factors were correlated with HH vector abundance. Higher vector counts were found in rural areas with low population density and among HHs close to roads and small streams. Vector counts were lower with increasing elevation and slope. Anopheles funestus was negatively associated with rainfall at lags of 2-6weeks, and An. gambiae was positively associated with rainfall at lags of 3-10 weeks. Both vectors had varying relationships with temperature. These results suggest thatmalaria vector control in Nchelenge district should occur throughout the year, with an increased focus on dry-season transmission and rural areas

Use of successional sowing in evaluating cowpea (Vigna unguiculata) adaptation to drought in the Sudan savannah zone. 2. Responseof reproductive traits

Two sets of experiments on cowpea sowing date were conducted in 1983–85 at Ouagadougou, Burkina Faso. One set tested six daylength-insensitive (DI) cultivars and the other compared four or five daylength-sensitive (DS) cultivars with one or two DI cultivars as controls. Sowing after inadequate rainfall, particularly when followed by drought stress, impeded seedling establishment and growth. Severe drought stress during the reproductive growth stages and prolonged drought stress throughout the crop season adversely affected flowering, flowering and subsequent yield. Cultivar differences in ability to withstand drought damage were observed. The ability of cultivars to (i) branch profusely, to compensate for stands lost by drought during seedling growth and (ii) flower at such a time that pod set and fill coincide with favourable climatic conditions appears to be a prerequisite for satisfactory adaptation to the Sudan savannah zone of semi-arid West Africa. Daylength-sensitivity and early maturity per se were inadequate to prevent yield losses under drought conditions

Use of successional sowing in evaluating cowpea (Vigna unguiculata) adaptation to drought in the Sudan savannah zone. 1. Seed yield response

The results of this study indicated that this procedure is sufficiently sensitive to reflect the effects of tillage, residue cover and crusting on infiltration data. Raindrop impact reduced infiltration rates by crusting the soil surface. However, most of the management systems that left about 30% of residue cover protected the soil from raindrop impact as evidenced by the higher effective hydraulic conductivity. It is concluded that the model developed by Green and Ampt in 1911 satisfactorily fitted the infiltration data obtained from protected and crusted soil profiles. Also, residue cover and crusting greatly influenced the Green and Ampt infiltration parameter value

An historical review of progress to control key cowpea biotic constraints in Burkina Faso

Cowpea farming practices have been ongoing for millennia and have always faced various challenges including diseases, insects, and weeds, that lower its yield to no more than 200 kg/ha. This economically and nutritionally important crop has been a major research focus of the International Institute of Tropical Agriculture (IITA) and of several national agricultural research systems (NARS) in sub-Saharan Africa (SSA) and partner universities. Researchers have begun to develop sustainable solutions that will minimize the use of synthetic pesticides for protecting the crop in the field and seeds in storage. Research activities of entomologists have made identification of pests possible while also ensuring better understanding about their biology and ecology and plant damaging relationships. Through joint efforts by IITA, NARS, universities, and advanced research institutions, and the support from financial partners via research networks, researchers were able to develop a wide range of improved varieties that tolerate yield limiting biotic stresses. Progress has been made in the protection of cowpea from the initial stages when application of synthetic insecticides was promoted through reduced frequency and targeted insecticide sprays to the deployment of natural enemies of the most economically important insect pests. The concept of integrated pest management has become a reality in sustainable cowpea production. The cowpea lines resulting from selections made among local farmers’ varieties under no insecticide application in Burkina Faso have reduced the need for pesticide application. Combined with application of insecticidal plant extracts, these selected lines can attain up to 600 kg/ha. Finally, it is now possible to store cowpea seeds without chemicals by using triple bagging which stifles bruchids (weevils) of air. Prospects include exploiting the possibilities of biological control and, at the same time, using advanced technological opportunities offered by biotechnology to control cowpea pests and minimize losses in the field and in storage

Complete Anopheles funestus mitogenomes reveal an ancient history of mitochondrial lineages and their distribution in southern and central Africa

Anopheles funestus s.s. is a primary vector of malaria in sub-Saharan Africa. Despite its important role in human Plasmodium transmission, evolutionary history, genetic diversity, and population structure of An. funestus in southern and central Africa remains understudied. We deep sequenced, assembled, and annotated the complete mitochondrial genome of An. funestus s.s. for the first time, providing a foundation for further genetic research of this important malaria vector species. We further analyzed the complete mitochondrial genomes of 43 An. funestus s.s. from three sites in Zambia, Democratic Republic of the Congo, and Tanzania. From these 43 mitogenomes we identified 41 unique haplotypes that comprised 567 polymorphic sites. Bayesian phylogenetic reconstruction confirmed the co-existence of two highly divergent An. funestus maternal lineages, herein defined as lineages I and II, in Zambia and Tanzania. The estimated coalescence time of these two mitochondrial lineages is ~500,000 years ago (95% HPD 426,000-594,000 years ago) with subsequent independent diversification. Haplotype network and phylogenetic analysis revealed two major clusters within lineage I, and genetic relatedness of samples with deep branching in lineage II. At this time, data suggest that the lineages are partially sympatric. This study illustrates that accurate retrieval of full mitogenomes of Anopheles vectors enables fine-resolution studies of intraspecies genetic relationships, population differentiation, and demographic history. Further investigations on whether An. funestus mitochondrial lineages represent biologically meaningful populations and their potential implications for malaria vector control are warranted