Spatial and temporal dynamics of malaria transmission in rural western Kenya

ABSTRACT: BACKGROUND: Understanding the impact of reducing Plasmodium falciparum malaria transmission requires estimates of the relationship between health outcomes and exposure to infectious mosquitoes. However, measures of exposure such as mosquito density and entomological inoculation rate (EIR) are generally aggregated over large areas and time periods, biasing the outcome-exposure relationship. There are few studies examining the extent and drivers of local variation in malaria exposure in endemic areas. METHODS: We describe the spatio-temporal dynamics of malaria transmission intensity measured by mosquito density and EIR in the KEMRI/CDC health and demographic surveillance system using entomological data collected during 2002-2004. Geostatistical zero inflated binomial and negative binomial models were applied to obtain location specific (house) estimates of sporozoite rates and mosquito densities respectively. Model-based predictions were multiplied to estimate the spatial pattern of annual entomological inoculation rate, a measure of the number of infective bites a person receive per unit of time. The models included environmental and climatic predictors extracted from satellite data, harmonic seasonal trends and parameters describing space-time correlation. RESULTS: Anopheles gambiae s.l was the main vector species accounting for 86% (n=2309) of the total collected mosquitoes with the remainder being Anopheles funestus. Sixty eight percent (757/1110) of the surveyed houses had no mosquitoes. Distance to water bodies, vegetation and day temperature were significantly associated with mosquito density. Overall annual point estimates of EIR were 6.7, 9.3 and 9.6 infectious bites per annum for 2002, 2003 and 2004 respectively. Monthly mosquito density and EIR varied over the study period peaking in May during the wet season. The predicted and observed densities and EIR showed a strong seasonal and spatial pattern over the study area. CONCLUSIONS: Spatio-temporal maps of malaria transmission intensity obtained in this study are not only useful in understanding variability in malaria epidemiology over small areas but also provides a high resolution exposure surface that can be used to analyse the impact of malaria exposure on mortalit

Assessing Feed Gaps on Smallholder Livestock Farms in Limpopo: Production System and Coping Strategies

Smallholder farms in southern Africa are predominantly mixed crop-livestock systems and often characterized by low productivity. Therefore, providing sufficient forage becomes a challenge that results first in feed gaps, i.e. the difference between the demand for and supply of forage, and secondly, in nutrient mining of the soil due to the overuse of the resources. However, the availability of forage follows potentially seasonal patterns. Hence, a key entry point for any intervention strategies for improvement is an assessment of forage quantity and quality throughout the year. Against this background, we investigated six locations, smallholders’ cattle production systems and their adaptation options in periods of feed deficit across three distinct agro-ecological zones in the Limpopo province (South Africa). We interviewed 90 farmers from May to September 2019 and found that farmers struggle in winter-spring (June – September) to access feed resources for their livestock. Most farmers mentioned that feed deficit in that period is a regular phenomenon. Mixed crop-livestock farmers stated that they rely on on-farm resources (crop residues) while sole livestock farmers stated that reducing herd size is a top adaptation option. Farmers also indicated that feed availability in required quantity and quality is the biggest constraint to sustaining livestock production throughout the year. This study demonstrates a sound assessment of the temporal pattern of feed gaps in Limpopo province and potential farmer avenues for their mitigation

Closing Feed Gaps by Winter Forage Production in Limpopo: What Is the Potential?

In southern Africa, livestock productivity in mixed crop-livestock systems is constrained by forage supply towards the end of the dry period. Opportunities to improve forage availability to close the temporal feed gap counteracting negative effects on production as well as on environment need to be explored. A promising option might be the planting of cover crops (CC) during the winter period. Hence, a field experiment was conducted in the Limpopo province (South Africa) during the autumn-winter period of 2019 at two sites (Syferkuil, Thohoyandu) with contrasting climatic conditions and soil type. We selected multi-functional C3 species – winter rye (Secale cereal L.) intensively used in the temperate region sown as pure stand and established at two sowing dates. We assessed forage production, soil water dynamics and nitrogen accumulation. In a second step, we tested the Agricultural Production Systems simulator (APSIM) model against the field trial data. We present here, preliminary results which show high potential growth when irrigated. Early planting of CC yielded the highest accumulated biomass (18 t DM ha-1 and 7 t DM ha-1 at Syferkuil and Thohoyandu, respectively) after 140 days while delayed planting (4 weeks after first planting) decreased biomass production. The model predictions rely heavily on pedo-climatic interactions which need further improvements

The International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three: A global synthesis

This ISAAC Phase Three synthesis provides summarised information on the main findings of the study, regional tables and figures related to the prevalence and severity of current symptoms of asthma, rhinoconjunctivitis and eczema in the main regions of the world. The large number of surveyed children (≈1,200,000), the large number of centres (233) and countries (98) that participated in ISAAC Phase Three makes this study the most comprehensive survey of these diseases ever undertaken. Globally, the prevalence for current asthma, rhinoconjunctivitis and eczema in the 13-14-year age group was 14.1%, 14.6% and 7.3%, respectively. In the 6-7-year age group the prevalence for current asthma, rhinoconjunctivitis and eczema was 11.7%, 8.5% and 7.9%, respectively. The study shows a wide variability in the prevalence and severity of asthma, rhinoconjunctivitis and eczema which occurs not just between regions and countries but between centres in the same country and centres in the same city. This study definitively establishes that the prevalence of those diseases can be very high in non-affluent centres with low socioeconomic conditions. The large variability also suggests a crucial role of local environment characteristics to determine the differences in prevalence between one place and another. Thus, ISAAC Phase Three has provided a large body of epidemiological information on asthma, rhinoconjunctivitis and eczema in childhood from contrasting environments which is expected to yield new clues about the aetiology of those conditions and reasons for their marked global variability. © 2012 SEICAP

Effectiveness of conditional cash transfers (Afya credits incentive) to retain women in the continuum of care during pregnancy, birth and the postnatal period in Kenya: a cluster-randomised trial

OBJECTIVES: Given high maternal and child mortality rates, we assessed the impact of conditional cash transfers (CCTs) to retain women in the continuum of care (antenatal care (ANC), delivery at facility, postnatal care (PNC) and child immunisation). DESIGN: We conducted an unblinded 1:1 cluster-randomised controlled trial. SETTING: 48 health facilities in Siaya County, Kenya were randomised. The trial ran from May 2017 to December 2019. PARTICIPANTS: 2922 women were recruited to the control and 2522 to the intervention arm. INTERVENTIONS: An electronic system recorded attendance and triggered payments to the participant's mobile for the intervention arm (US$4.5), and phone credit for the control arm (US$0.5). Eligibility criteria were resident in the catchment area and access to a mobile phone. PRIMARY OUTCOMES: Primary outcomes were any ANC, delivery, any PNC between 4 and 12 months after delivery, childhood immunisation and referral attendance to other facilities for ANC or PNC. Given problems with the electronic system, primary outcomes were obtained from maternal clinic books if participants brought them to data extraction meetings (1257 (50%) of intervention and 1053 (36%) control arm participants). Attendance at referrals to other facilities is not reported because of limited data. RESULTS: We found a significantly higher proportion of appointments attended for ANC (67% vs 60%, adjusted OR (aOR) 1.90; 95% CI 1.36 to 2.66) and child immunisation (88% vs 85%; aOR 1.74; 95% CI 1.10 to 2.77) in intervention than control arm. No intervention effect was seen considering delivery at the facility (90% vs 92%; aOR 0.58; 95% CI 0.25 to 1.33) and any PNC attendance (82% vs 81%; aOR 1.25; 95% CI 0.74 to 2.10) separately. The pooled OR across all attendance types was 1.64 (1.28 to 2.10). CONCLUSIONS: Demand-side financing incentives, such as CCTs, can improve attendance for appointments. However, attention needs to be paid to the technology, the barriers that remain for delivery at facility and PNC visits and encouraging women to attend ANC visits within the recommended WHO timeframe. TRIAL REGISTRATION: NCT03021070

Considering effects of temperature and photoperiod on growth and development of lablab purpureus (l.) Sweet in the search of short-season accessions for smallholder farming systems

Legumes have gained increased importance in smallholder farming systems of sub-Saharan Africa due to their contribution to household nutrition and health and their ability to grow in low fertility soils. With unpredictable and highly variable rainfall characteristics of the semi-arid areas, short-season grain types are seen as a promising option for drought avoidance. Knowledge of phenological development and, in particular, time to flowering is crucial information needed for estimating the possible production success of new accessions to new environments. The photoperiod-sensitivity of 10 promising short-season Lablab purpureus (L.) Sweet accessions (CPI 525313, CPI 52533, CPI 52535, CPI 52535, CPI 52552, CPI 52554, CPI 60795, CPI 81364, CQ 3620, Q 6880B) were evaluated for their response to varying temperature and daylength regimes in field trials in Limpopo province, South Africa and under controlled conditions in growth chamber experiments in Göttingen, Germany. Photoperiod sensitivity was quantified using the triple-plane rate model of flowering response with time to flowering expressed in thermal time (Tt, °Cd). Additionally, piecewise regression analysis was conducted to estimate the critical photoperiod (Pc) above which time to flowering was delayed significantly. Relatively high variation of time to flowering amongst and within accessions in days after planting (DAP) was observed, ranging from 60 to 120 DAP depending on sowing date or daylength/temperature regime. Furthermore, a clear positive effect of temperature on growth and development of the tested accessions was found and time to flowering expressed as thermal time were consistent for the tested accessions, ranging from 600 to 800 °Cd for daylength 110 DAP. The tested lablab accessions are therefore considered photoperiod insensitive, or weakly photoperiod responsive and are classified as short-day plants (SDP). Since daylength does not exceed 13 h between the latitudes 30 N to 30 S, these lablab accessions are recommended for further testing as short-duration grain legumes

Relationship between Selected Personal Determinants and Examination Cheating among Kenyan Secondary School Students

The present study investigated the relationship between selected personal determinants and examination cheating among Kenyan secondary school students. This study used a Sequential Explanatory design. The target population was 51,900 students in Kisumu County within 153 public secondary schools categorized as 2 National secondary schools, 21 extra county schools, and 130 county and sub-county schools. A simple random sampling technique was used to determine sample size which comprised of 380 respondents since the study was confined within specific ecological boundary which was public secondary schools. Data collection instruments included questionnaires, for general data collection from the respondents and in-depth interview schedules for one to one interview of respondents. The finding of the study shows that there was statistically significant positive correlation (r=.592, n=360,