Household-level and surrounding peri-domestic environmental characteristics associated with malaria vectors Anopheles arabiensis and Anopheles funestus along an urban–rural continuum in Blantyre, Malawi

Abstract Background Malaria is increasing in some recently urbanized areas that historically were considered lower risk. Understanding what drives urban transmission is hampered by inconsistencies in how “urban” contexts are defined. A dichotomized “urban–rural” approach, based on political boundaries may misclassify environments or fail to capture local drivers of risk. Small-scale agriculture in urban or peri-urban settings has been shown to be a major risk determinant. Methods Household-level Anopheles abundance patterns in and around Malawi’s commercial capital of Blantyre (~ 1.9 M pop.) were analysed. Clusters (N = 64) of five houses each located at 2.5 km intervals along eight transects radiating out from Blantyre city centre were sampled during rainy and dry seasons of 2015 and 2016. Mosquito densities were measured inside houses using aspirators to sample resting mosquitoes, and un-baited CDC light traps to sample host seeking mosquitoes. Results Of 38,895 mosquitoes captured, 91% were female and 87% were Culex spp. Anopheles females (N = 5058) were primarily captured in light traps (97%). Anopheles abundance was greater during rainy seasons. Anopheles funestus was more abundant than Anopheles arabiensis, but both were found on all transects, and had similar associations with environmental risk factors. Anopheles funestus and An. arabiensis females significantly increased with distance from the urban centre, but this trend was not consistent across all transects. Presence of small-scale agriculture was predictive of greater Anopheles spp. abundance, even after controlling for urbanicity, number of nets per person, number of under-5-year olds, years of education, and season. Conclusions This study revealed how small-scale agriculture along a rural-to-urban transition was associated with An. arabiensis and An. funestus indoor abundances, and that indoor Anopheles density can be high within Blantyre city limits, particularly where agriculture is present. Typical rural areas with lower house density and greater distance from urban centres reflected landscapes more suitable for Anopheles reproduction and house invasion. However, similar characteristics and elevated Anopheles abundances were also found around some houses within the city limits. Thus, dichotomous designations of “urban” or “rural” can obscure important heterogeneity in the landscape of Plasmodium transmission, suggesting the need for more nuanced assessment of urban malaria risk and prevention efforts.https://deepblue.lib.umich.edu/bitstream/2027.42/144215/1/12936_2018_Article_2375.pd

Bed net use among school-aged children after a universal bed net campaign in Malawi

Abstract Background Recent data from Malawi suggest that school-aged children (SAC), aged 5–15 years, have the highest prevalence of Plasmodium falciparum infection among all age groups. They are the least likely group to utilize insecticide-treated nets (ITNs), the most commonly available intervention to prevent malaria in Africa. This study examined the effects of a universal ITN distribution campaign, and their durability over time in SAC in Malawi. This study identified factors that influence net usage among SAC and how these factors changed over time. Methods Cross-sectional surveys using cluster random sampling were conducted at the end of each rainy and dry season in southern Malawi from 2012 to 2014; six surveys were done in total. Mass net distribution occurred between the first and second surveys. Data were collected on household and individual net usage as well as demographic information. Statistical analyses used generalized linear mixed models to account for clustering at the household and neighbourhood level. Results There were 7347 observations from SAC and 14,785 from young children and adults. SAC used nets significantly less frequently than the rest of the population (odds ratio (OR) from 0.14 to 0.38). The most important predictors of net usage among SAC were a lower ratio of people to nets in a household and higher proportion of nets that were hanging at the time of survey. Older SAC (11–15 years) were significantly less likely to use nets than younger SAC (5–10 years) [OR = 0.24 (95 % CI: 0.21, 0.28)]. The universal bed net campaign led to a statistically significant population-wide increase in net use, however net use returned to near baseline within 3 years. Conclusions This study suggests that a single universal net distribution campaign, in combination with routine distribution through health clinics is not sufficient to cause a sustained increase in net usage among SAC. Novel approaches to ITN distribution, such as school-based distribution, may be needed to address the high prevalence of infection in SAC.http://deepblue.lib.umich.edu/bitstream/2027.42/134523/1/12936_2016_Article_1178.pd

Insecticide-treated net effectiveness at preventing Plasmodium falciparum infection varies by age and season

Abstract Background After increasing coverage of malaria interventions, malaria prevalence remains high in Malawi. Previous studies focus on the impact of malaria interventions among children under 5 years old. However, in Malawi, the prevalence of infection is highest in school-aged children (SAC), ages 5 to 15 years. This study examined the interaction between age group and insecticide-treated net (ITN) use for preventing individual and community-level infection in Malawi. Methods Six cross-sectional surveys were conducted in the rainy and dry seasons in southern Malawi from 2012 to 2014. Data were collected on household ITN usage and demographics. Blood samples for detection of Plasmodium falciparum infection were obtained from all household members present and over 6 months of age. Generalized linear mixed models were used to account for clustering at the household and community level. Results There were 17,538 observations from six surveys. The association between ITN use and infection varied by season in SAC, but not in other age groups. The adjusted odds ratio (OR) for infection comparing ITN users to non-users among SAC in the rainy season and dry season was 0.78 (95% CI 0.56, 1.10) and 0.51 (0.35, 0.74), respectively. The effect of ITN use did not differ between children under five and adults. Among all non-SACs the OR for infection was 0.78 (0.64, 0.95) in those who used ITNs compared to those that did not. Community net use did not protect against infection. Conclusions Protection against infection with ITN use varies by age group and season. Individual estimates of protection are moderate and a community-level effect was not detected. Additional interventions to decrease malaria prevalence are needed in Malawi.http://deepblue.lib.umich.edu/bitstream/2027.42/135726/1/12936_2017_Article_1686.pd

Learner Treatment Kit (school-based malaria diagnosis and treatment in southern Malawi): Study data and support materials

A set of data collection tools, STATA .do processing scripts, and resultant datasets produced as part of the Learner Treatment Kit (LTK) Project, a study funded to evaluate the impact of a school-based programme of malaria diagnosis and treatment (malaria case management) as part of a wider school first-aid kit exploring school attendance, health and education outcomes. The study conducted a cluster randomized controlled trial in 58 primary schools in TA Chikowi, Zomba district of southern Malawi. The intervention, implemented between 2013-2015 in 29 randomly selected schools from the total of 58 schools, comprised providing free-of-charge malaria rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) to primary schools to be used by trained teachers to diagnose and treat uncomplicated malaria, as part of basic first aid kits known as "Learner Treatment Kits" (LTKs). The primary outcome was school attendance, assessed through teacher-recorded school attendance registers and periodic spot checks. Secondary outcomes included prevalence of Plasmodium spp. infection, anaemia, educational performance, self-reported child wellbeing, and health seeking behaviour. The trial is registered with ClinicalTrials.gov, NCT02213211

Learner Treatment Kit (school-based malaria diagnosis and treatment in southern Malawi): Study data and support materials

A set of data collection tools, STATA .do processing scripts, and resultant datasets produced as part of the Learner Treatment Kit (LTK) Project, a study funded to evaluate the impact of a school-based programme of malaria diagnosis and treatment (malaria case management) as part of a wider school first-aid kit exploring school attendance, health and education outcomes. The study conducted a cluster randomized controlled trial in 58 primary schools in TA Chikowi, Zomba district of southern Malawi. The intervention, implemented between 2013-2015 in 29 randomly selected schools from the total of 58 schools, comprised providing free-of-charge malaria rapid diagnostic tests (RDTs) and artemisinin-based combination therapy (ACT) to primary schools to be used by trained teachers to diagnose and treat uncomplicated malaria, as part of basic first aid kits known as "Learner Treatment Kits" (LTKs). The primary outcome was school attendance, assessed through teacher-recorded school attendance registers and periodic spot checks. Secondary outcomes included prevalence of Plasmodium spp. infection, anaemia, educational performance, self-reported child wellbeing, and health seeking behaviour. The trial is registered with ClinicalTrials.gov, NCT02213211

Determinants of self-reported correct knowledge about tuberculosis transmission among men and women in Malawi: evidence from a nationwide household survey

Abstract: Background: Correct knowledge about transmission of tuberculosis (TB) can influence better health-seeking behaviors, and in turn, it can aid TB prevention in society. Therefore, this study aimed to examine the prevalence and predictors of self-reported correct knowledge about TB transmission among adults in Malawi. Methods: We conducted a secondary analysis of the data obtained from the Malawi Demographic and Health Survey, 2015/16 (MDHS 2015/16). Questions regarding self-reported TB transmission were computed to evaluate the correct knowledge about TB transmission. The factors associated with the correct knowledge about Tb were assessed using univariate and multivariable logistic regression. Results: Overall, the prevalence of correct knowledge about TB transmission in the general population of Malawian adults was 61.5%. Specifically, the prevalence of correct knowledge about TB transmission was 63.6 and 60.8% in men and women, respectively. Those aged 35–44 years, having secondary or high education, belonging to the richest household, being exposed to mass media, being in professional/technical/managerial, having knowledge that “TB can be cured”, and those living in urban areas were significantly associated with correct knowledge about TB transmission. Conclusions: The findings of this study show that if appropriate strategies for TB communication and education to address the rural masses, young individuals, poor individuals, and individuals in the agriculture sector are put it place, can enhance TB prevention in Malawi

School-Age Children Are a Reservoir of Malaria Infection in Malawi

Malaria surveillance and interventions in endemic countries often target young children at highest risk of malaria morbidity and mortality. We aimed to determine whether school-age children and adults not captured in surveillance serve as a reservoir for malaria infection and may contribute to malaria transmission. Cross-sectional surveys were conducted in one rainy and one dry season in southern Malawi. Demographic and health information was collected for all household members. Blood samples were obtained for microscopic and PCR identification of Plasmodium falciparum. Among 5796 individuals aged greater than six months, PCR prevalence of malaria infection was 5%, 10%, and 20% in dry, and 9%, 15%, and 32% in rainy seasons in Blantyre, Thyolo, and Chikhwawa, respectively. Over 88% of those infected were asymptomatic. Participants aged 6–15 years were at higher risk of infection (OR=4.8; 95%CI, 4.0–5.8) and asymptomatic infection (OR=4.2; 95%CI, 2.7–6.6) than younger children in all settings. School-age children used bednets less frequently than other age groups. Compared to young children, school-age children were brought less often for treatment and more often to unreliable treatment sources. Conclusion: School-age children represent an underappreciated reservoir of malaria infection and have less exposure to antimalarial interventions. Malaria control and elimination strategies may need to expand to include this age group