Malaria Outbreak Facilitated by Appearance of Vector-Breeding Sites after Heavy Rainfall and Inadequate Preventive Measures: Nwoya District, Northern Uganda, February–May 2018

Background: Climate change is expected to increase the frequency of flooding events. Although rainfall is highly correlated with mosquito-borne diseases (MBD) in humans, less research focuses on understanding the impact of flooding events on disease incidence. This lack of research presents a significant gap in climate change–driven disease forecasting. Objectives: We conducted a scoping review to assess the strength of evidence regarding the potential relationship between flooding and MBD and to determine knowledge gaps. Methods: PubMed, Embase, and Web of Science were searched through 31 December 2020 and supplemented with review of citations in relevant publications. Studies on rainfall were included only if the operationalization allowed for distinction of unusually heavy rainfall events. Data were abstracted by disease (dengue, malaria, or other) and stratified by post-event timing of disease assessment. Studies that conducted statistical testing were summarized in detail. Results: From 3,008 initial results, we included 131 relevant studies (dengue , malaria , other MBD ). Dengue studies indicated short-term ( ) decreases and subsequent (1–4 month) increases in incidence. Malaria studies indicated post-event incidence increases, but the results were mixed, and the temporal pattern was less clear. Statistical evidence was limited for other MBD, though findings suggest that human outbreaks of Murray Valley encephalitis, Ross River virus, Barmah Forest virus, Rift Valley fever, and Japanese encephalitis may follow flooding. Discussion: Flooding is generally associated with increased incidence of MBD, potentially following a brief decrease in incidence for some diseases. Methodological inconsistencies significantly limit direct comparison and generalizability of study results. Regions with established MBD and weather surveillance should be leveraged to conduct multisite research to a ) standardize the quantification of relevant flooding, b ) study nonlinear relationships between rainfall and disease, c ) report outcomes at multiple lag periods, and d ) investigate interacting factors that modify the likelihood and severity of outbreaks across different settings. https://doi.org/10.1289/EHP8887

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“…Similarly, during an outbreak investigation following a major flood in Uganda, Nsereko et al. found cases had significantly (

) higher odds of exposure to stagnant water around the home for 3–5 d after flooding in comparison with controls ( Nsereko et al. 2020 ).…”

Section: Resultsmentioning

confidence: 96%

“…2020 ). Neither study reported their statistical results in a way that could be linked to a specific lag period, though the Uganda outbreak investigation indicated that the outbreak began approximately 40 d after the flood ( Nsereko et al. 2020 ).…”

Section: Resultsmentioning

confidence: 99%

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

Coalson

Anderson

Santos

et al. 2021

Environ Health Perspect

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“…This could be explained by the fact that stagnant waters are potential breeding sites of Anopheles mosquitoes. Therefore, having such water around the house could increase the population of mosquitoes and facilitate malaria transmission [ 56 ].…”

Section: Discussionmentioning

confidence: 99%

Malaria-associated risk factors among adolescents living in areas with persistent transmission in Senegal: a case–control study

Tairou

Diallo²,

et al. 2022

Malar J

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Background In Senegal, malaria morbidity has sharply decreased over these past years. However, malaria epidemiology remains heterogeneous with persistent transmission in the southeastern part of the country and many cases among older children and adolescents. Little is known about factors associated with clinical malaria among this group. A better understanding of malaria transmission among this newly emerging vulnerable group will guide future interventions targeting this population group. This study aimed to identify factors associated with clinical malaria among adolescents in Senegal. Methods A case–control study was conducted from November to December 2020 in four health posts located in the Saraya district. Cases were defined as adolescents (10–19 years) with an uncomplicated malaria episode with fever (temperature > 37.5°) or a history of fever and positive malaria rapid diagnostic test (RDT). Controls were from the same age group, living in the neighbourhood of the case, presenting a negative RDT. A standardized, pre-tested questionnaire was administered to each study participant followed by a home visit to assess the participant's living conditions. Factors associated with clinical malaria were assessed using stepwise logistic regression analysis. Results In total, 492 individuals were recruited (246 cases and 246 controls). In a multivariate analysis, factors associated with clinical malaria included non-use of long-lasting insecticidal net (LLIN) (aOR = 2.65; 95% CI 1.58–4.45), non-use of other preventive measures (aOR = 2.51; 95% CI 1.53–4.11) and indoor sleeping (aOR = 3.22; 95% CI 1.66–6.23). Protective factors included 15–19 years of age (aOR = 0.38; 95% CI 0.23–0.62), absence of stagnant water around the house (aOR = 0.27; 95% CI 0.16–0.44), having a female as head of household (aOR = 0.47; 95% CI 0.25–0.90), occupation such as apprentice (OR = 0.24; 95% CI 0.11–0.52). Conclusions The study revealed that environmental factors and non-use of malaria preventive measures are the main determinants of malaria transmission among adolescents living in areas with persistent malaria transmission in Senegal. Strategies aimed at improving disease awareness and access to healthcare interventions, such as LLINs, are needed to improve malaria control and prevention among these vulnerable groups.

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“…This could be explained by the fact that stagnant waters are potential breeding sites of Anopheles mosquitoes. So, having such water around the house could increase the population of mosquitoes and hence facilitate malaria transmission [42].…”

Section: Discussionmentioning

confidence: 99%

Malaria Associated Risk Factors Among Adolescent Living in Areas With Persisting Transmission in Senegal: a Case Control Study.

Tairou¹,

Diallo²,

Sy³

et al. 2021

Preprint

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Background: In Senegal, malaria morbidity has shapely felt down over these past years. However, malaria epidemiology remains heterogeneous with persisting transmission in the southeastern part of the country and more important number of cases arising among older children and adolescents. Little is known about factors associated with clinical malaria among this group. A better understanding of malaria transmission among this new vulnerable group will guide future interventions targeting these key populations. This study aimed to identify factors associated with clinical malaria among adolescents in Senegal. Methods: A case control study was conducted from November to December 2020 in four health posts located in Saraya district. Cases were defined as adolescents (10-19 years) with uncomplicated malaria episode with fever (Temperature>37.5°) or history of fever and a positive malaria RDT. Controls were from the same age group, living in the neighborhood of the case, presenting a negative RDT. A standardized, pre-tested questionnaire was administered to each participant followed by home visit to assess participant’s living conditions. Factors associated with clinical malaria was assessed using a Stepwise Logistic regression analysis.Results: In total, 492 individuals were recruited (246 cases and 246 controls). In a multivariate analysis, factors associated with clinical malaria included non-use of bed net (aOR=2.65; 95% CI =1.58 - 4.45), non-use of other preventive measures (aOR=2.51; 95% CI=1.53 - 4.11) and indoor sleeping (aOR=3.22; 95%CI =1.66- 6.23). Protective factors included age of 15-19 years (aOR=0.38; 95% CI 0.23 - 0.62), absence of stagnant water around the house (aOR=0.27; 95% CI=0.16 - 0.44), having a female as head of household (aOR=0.47; 95% CI=0.25 - 0.90), occupation such as apprentice (OR=0.24; 95%CI=0.11 - 0.52).Conclusions: The study revealed that environmental factors and non-use of malaria preventive measures are the main determinant of malaria transmission among adolescents living in areas with persisting malaria transmission in Senegal. Strategies aiming at improving disease awareness and access to health care interventions such as LLIN are thus needed to improve malaria control and prevention among these vulnerable groups.

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Malaria Outbreak Facilitated by Appearance of Vector-Breeding Sites after Heavy Rainfall and Inadequate Preventive Measures: Nwoya District, Northern Uganda, February–May 2018

Cited by 15 publications

References 33 publications

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

The Complex Epidemiological Relationship between Flooding Events and Human Outbreaks of Mosquito-Borne Diseases: A Scoping Review

Malaria-associated risk factors among adolescents living in areas with persistent transmission in Senegal: a case–control study

Malaria Associated Risk Factors Among Adolescent Living in Areas With Persisting Transmission in Senegal: a Case Control Study.

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