Modelling the influence of temperature and rainfall on malaria incidence in four endemic provinces of Zambia using semiparametric Poisson regression

Shimaponda-Mataa, Nzooma M.; Tembo-Mwase, Enala; Gebreslasie, Michael; Achia, Thomas; Mukaratirwa, Samson

doi:10.1016/j.actatropica.2016.11.007

Cited by 19 publications

(29 citation statements)

References 20 publications

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“…The nonlinear relationship between the first latent factor component (constituted by humidity, precipitation, wet days, and PET) and malaria prevalence was similar to that observed elsewhere [29,33,[54][55][56]. Studies have shown that exposed small pools of stagnant water during wet seasons or at the beginning of dry season encourages mosquito survival and larvae development [29,57], as heavy rainfall may flush away the breeding larvae, thereby decreasing the number of malaria causing mosquitoes.…”

Section: Discussionsupporting

confidence: 76%

“…Few published studies in Nigeria have linked malaria prevalence to several influencing factors, including climate and environmental conditions [2,10,11,13,15,[17][18][19][20], socioeconomic factors [15,[21][22][23], geographical factors [10,[13][14][15]18,24], and control strategies as well as prevalence of other febrile illnesses [22,[25][26][27]. Additionally, several authors in other malaria endemic countries have investigated the correlation between malaria and important meteorological variables as observed in Venezuela [6][7][8][9], in Zimbabwe [28], in Zambia [29,30], in Côte D'Ivoire [31], in Ghana [32], in Burundi [33], in Ethiopia [34,35] and many more. It was found that malaria infections are not uniformly distributed in space.…”

Section: Introductionmentioning

confidence: 99%

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Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

Ugwu¹,

Zewotir²

2020

JEGH

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Although malaria burden has declined globally following scale up of intervention, the disease has remained a leading cause of hospitalization and deaths among children aged under-5 years in Nigeria. Malaria is known to be related to climate and environmental conditions. Previous research has usually studied the effects of these factors, neglecting possible correlation between them, high correlation among variables is a source of multicollinearity that induces overfitting in regression modelling. In this paper, a factor analysis was first introduced to circumvent the issue of multicollinearity and a Generalized Additive Model (GAM) was subsequently explored to identify the important risk factors that might influence the prevalence of childhood malaria in Nigeria. The GAM incorporated the complexity of the survey data, while simultaneously modelling the nonlinear and spatial random effects to allow a more precise identification of the major malaria risk factors that influence the geographical distribution of the disease. From our findings, the three latent factor components (constituted by humidity, precipitation, potential evapotranspiration, and wet days/maximum and minimum temperature/proximity to permanent waters, respectively) were significantly associated with malaria prevalence. Our analysis also detected statistically significant and nonlinear effect of altitude: the risk of malaria increased with lower values but declined sharply with higher values. A significant spatial variability in under-5 malaria prevalence across the survey clusters was also observed; malaria burden was higher in the northern part of Nigeria. Investigating the impact of important risk factors and geographical location on childhood malaria is of high relevance for the sustainable development goals (SDGs) 2015-2030 Agenda on malaria eradication, and we believe that the information obtained from this study and the generated risk maps can be useful to effectively target intervention efforts to high-risk areas based on climate and environmental context.

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Section: Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

Ugwu¹,

Zewotir²

2020

JEGH

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“…is is consistent with other studies that studied malaria determinants in Zambia [27,28]. Antimalarial drugs such as artemisinin combination therapies (ACTs) are known to clear parasiteamia within few days of commencement of effective treatment; one study in Cote d'Ivoire found a median parasite clearance of 30 hrs [29].…”

Section: Discussionsupporting

confidence: 85%

Investigating the Effect of Prompt Treatment on Malaria Prevalence in Children Aged below Five Years in Zambia: A Nested Case-Control Study in a Cross-Sectional Survey

Mukumbuta

2020

Advances in Public Health

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Background. In a highly malaria endemic country like Zambia, prompt treatment of cases is known to reduce morbidity and mortality; however, it is not known whether it has a role as an effective prevention strategy because of the presence of asymptomatic chronic carriers who do not seek treatment and maintain the reservoirs of infection in the population. This study investigated the role of treatment of malaria cases as a prevention strategy in low, moderate, and high endemic settings. Methods. A nested case-control design was employed using datasets from a large countrywide national Malaria Indicator Survey of 2015. Self-reported malaria cases (n = 209) who took treatment in the two weeks preceding the survey were matched with controls (n = 511) who did not report malaria and did not take treatment during the same period using nearest neighbour propensity score matching for age, sex, and district. The data were analysed using conditional logistic regression in STATA version 15.1. Results. The malaria cases were more likely to be from rural areas (p=0.001), poorest households (p=0.049), and who lived in improvised housing structures (p=0.004) compared with the controls. Data from low and moderate malaria endemic areas did not have sufficient cases for the analysis to proceed; however, data from high endemic areas showed borderline evidence (p=0.054) that prompt treatment reduces the risk of malaria by almost half in the short-term aOR 0.057 (95% CI 0.32–1.01). Conclusion. We found borderline evidence which suggests that prompt treatment of malaria cases even in high endemic areas has potential to reduce the risk of malaria by almost half in the short term.

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“…Dlamini et al constructed multiple models that correlate mosquito larva abundance with 4 weeks lagged land surface temperature [35]. The non-linear patterns of temperature and precipitation relevant to malaria transmission have been discussed as well [36, 37]. …”

Section: Discussionmentioning

confidence: 99%

Assessment of climate-driven variations in malaria incidence in Swaziland: toward malaria elimination

Chuang

Soble

Ntshalintshali

et al. 2017

Malar J

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BackgroundSwaziland aims to eliminate malaria by 2020. However, imported cases from neighbouring endemic countries continue to sustain local parasite reservoirs and initiate transmission. As certain weather and climatic conditions may trigger or intensify malaria outbreaks, identification of areas prone to these conditions may aid decision-makers in deploying targeted malaria interventions more effectively.MethodsMalaria case-surveillance data for Swaziland were provided by Swaziland’s National Malaria Control Programme. Climate data were derived from local weather stations and remote sensing images. Climate parameters and malaria cases between 2001 and 2015 were then analysed using seasonal autoregressive integrated moving average models and distributed lag non-linear models (DLNM).ResultsThe incidence of malaria in Swaziland increased between 2005 and 2010, especially in the Lubombo and Hhohho regions. A time-series analysis indicated that warmer temperatures and higher precipitation in the Lubombo and Hhohho administrative regions are conducive to malaria transmission. DLNM showed that the risk of malaria increased in Lubombo when the maximum temperature was above 30 °C or monthly precipitation was above 5 in. In Hhohho, the minimum temperature remaining above 15 °C or precipitation being greater than 10 in. might be associated with malaria transmission.ConclusionsThis study provides a preliminary assessment of the impact of short-term climate variations on malaria transmission in Swaziland. The geographic separation of imported and locally acquired malaria, as well as population behaviour, highlight the varying modes of transmission, part of which may be relevant to climate conditions. Thus, the impact of changing climate conditions should be noted as Swaziland moves toward malaria elimination.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-017-1874-0) contains supplementary material, which is available to authorized users.

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Modelling the influence of temperature and rainfall on malaria incidence in four endemic provinces of Zambia using semiparametric Poisson regression

Cited by 19 publications

References 20 publications

Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

Evaluating the Effects of Climate and Environmental Factors on Under-5 Children Malaria Spatial Distribution Using Generalized Additive Models (GAMs)

Investigating the Effect of Prompt Treatment on Malaria Prevalence in Children Aged below Five Years in Zambia: A Nested Case-Control Study in a Cross-Sectional Survey

Assessment of climate-driven variations in malaria incidence in Swaziland: toward malaria elimination

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