Quantifying the impact of decay in bed-net efficacy on malaria transmission

We modeled the impact of bed-net use and insecticide treated nets (ITNs), temperature, and treatment on malaria transmission dynamics using ordinary differential equations. To achieve this we formulated a simple model of mosquito biting rate that depends on temperature and usage of insecticides treated bed nets. We conducted global uncertainty and sensitivity analysis using Latin Hypercube Sampling (LHC) and Partial Rank Correlation Coefficient (PRCC) in order to find the most effective parameters that affect malaria transmission dynamics. We established the existence of the region where the model is epidemiologically feasible. We conducted the stability analysis of the disease-free equilibrium by the threshold parameter. We found the condition for the existence of the endemic equilibrium and provided necessary condition for its stability. Our results show that the peak of mosquitoes biting rate occurs at a range of temperature values not on a single value as previously reported in literature. The results also show that the combination of treatment and ITNs usage is the most effective intervention strategy towards control and eradication of malaria transmissions. Sensitivity analysis results indicate that the biting rate and the mosquitoes death rates are the most important parameters in the dynamics of malaria transmission.

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Impact of an accelerated melting of Greenland on malaria distribution over Africa

Nature Communications ◽

10.1038/s41467-021-24134-4 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Alizée Chemison ◽

Gilles Ramstein ◽

Adrian M. Tompkins ◽

Dimitri Defrance ◽

Guigone Camus ◽

...

Keyword(s):

Climate Change ◽

Malaria Transmission ◽

Ice Sheet ◽

Transmission Risk ◽

Future Climate Change ◽

Climate Change Scenarios ◽

Climate Change Risk ◽

System A ◽

Climate Simulations ◽

The Impact

AbstractStudies about the impact of future climate change on diseases have mostly focused on standard Representative Concentration Pathway climate change scenarios. These scenarios do not account for the non-linear dynamics of the climate system. A rapid ice-sheet melting could occur, impacting climate and consequently societies. Here, we investigate the additional impact of a rapid ice-sheet melting of Greenland on climate and malaria transmission in Africa using several malaria models driven by Institute Pierre Simon Laplace climate simulations. Results reveal that our melting scenario could moderate the simulated increase in malaria risk over East Africa, due to cooling and drying effects, cause a largest decrease in malaria transmission risk over West Africa and drive malaria emergence in southern Africa associated with a significant southward shift of the African rain-belt. We argue that the effect of such ice-sheet melting should be investigated further in future public health and agriculture climate change risk assessments.

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The impact of indoor residual spraying on Plasmodium falciparum microsatellite variation in an area of high seasonal malaria transmission in Ghana, West Africa

Molecular Ecology ◽

10.1111/mec.16029 ◽

2021 ◽

Author(s):

Dionne C. Argyropoulos ◽

Shazia Ruybal‐Pesántez ◽

Samantha L. Deed ◽

Abraham R. Oduro ◽

Samuel K Dadzie ◽

...

Keyword(s):

Plasmodium Falciparum ◽

West Africa ◽

Malaria Transmission ◽

Indoor Residual Spraying ◽

Microsatellite Variation ◽

The Impact

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Contribution of Asymptomatic Plasmodium Infections to the Transmission of Malaria in Kayin State, Myanmar

The Journal of Infectious Diseases ◽

10.1093/infdis/jiy686 ◽

2018 ◽

Vol 219 (9) ◽

pp. 1499-1509 ◽

Cited By ~ 14

Author(s):

Victor Chaumeau ◽

Ladda Kajeechiwa ◽

Bénédicte Fustec ◽

Jordi Landier ◽

Saw Naw Nyo ◽

...

Keyword(s):

Malaria Transmission ◽

Entomological Inoculation Rate ◽

Fold Increase ◽

Estimating Equation ◽

Malaria Prevalence ◽

Pcr Analysis ◽

Asymptomatic Malaria ◽

Asymptomatic Infections ◽

Greater Mekong Subregion ◽

The Impact

Abstract Background The objective of mass antimalarial drug administration (MDA) is to eliminate malaria rapidly by eliminating the asymptomatic malaria parasite reservoirs and interrupting transmission. In the Greater Mekong Subregion, where artemisinin-resistant Plasmodium falciparum is now widespread, MDA has been proposed as an elimination accelerator, but the contribution of asymptomatic infections to malaria transmission has been questioned. The impact of MDA on entomological indices has not been characterized previously. Methods MDA was conducted in 4 villages in Kayin State (Myanmar). Malaria mosquito vectors were captured 3 months before, during, and 3 months after MDA, and their Plasmodium infections were detected by polymerase chain reaction (PCR) analysis. The relationship between the entomological inoculation rate, the malaria prevalence in humans determined by ultrasensitive PCR, and MDA was characterized by generalized estimating equation regression. Results Asymptomatic P. falciparum and Plasmodium vivax infections were cleared by MDA. The P. vivax entomological inoculation rate was reduced by 12.5-fold (95% confidence interval [CI], 1.6–100-fold), but the reservoir of asymptomatic P. vivax infections was reconstituted within 3 months, presumably because of relapses. This was coincident with a 5.3-fold (95% CI, 4.8–6.0-fold) increase in the vector infection rate. Conclusion Asymptomatic infections are a major source of malaria transmission in Southeast Asia.

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Modeling the Dynamics of Malaria Transmission with Bed Net Protection Perspective

Applied Mathematics ◽

10.4236/am.2014.519298 ◽

2014 ◽

Vol 05 (19) ◽

pp. 3156-3205 ◽

Cited By ~ 4

Author(s):

Jean Claude Kamgang ◽

Vivient Corneille Kamla ◽

Stéphane Yanick Tchoumi

Keyword(s):

Malaria Transmission ◽

Bed Net

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Exploring the Impact of Climate Variability on Malaria Transmission Using a Dynamic Mosquito-Human Malaria Model

The Open Infectious Diseases Journal ◽

10.2174/1874279301810010088 ◽

2018 ◽

Vol 10 (1) ◽

pp. 88-100 ◽

Cited By ~ 5

Author(s):

Gbenga J. Abiodun ◽

Peter J. Witbooi ◽

Kazeem O. Okosun ◽

Rajendra Maharaj

Keyword(s):

Climate Variability ◽

Malaria Transmission ◽

Malaria Incidence ◽

Principal Component ◽

Wavelet Coherence ◽

Human Malaria ◽

Kwazulu Natal ◽

The Impact ◽

Wavelet Coherence Analysis ◽

Malaria Model

Introduction: The reasons for malaria resurgence mostly in Africa are yet to be well understood. Although the causes are often linked to regional climate change, it is important to understand the impact of climate variability on the dynamics of the disease. However, this is almost impossible without adequate long-term malaria data over the study areas. Methods: In this study, we develop a climate-based mosquito-human malaria model to study malaria dynamics in the human population over KwaZulu-Natal, one of the epidemic provinces in South Africa, from 1970-2005. We compare the model output with available observed monthly malaria cases over the province from September 1999 to December 2003. We further use the model outputs to explore the relationship between the climate variables (rainfall and temperature) and malaria incidence over the province using principal component analysis, wavelet power spectrum and wavelet coherence analysis. The model produces a reasonable fit with the observed data and in particular, it captures all the spikes in malaria prevalence. Results: Our results highlight the importance of climate factors on malaria transmission and show the seasonality of malaria epidemics over the province. Results from the principal component analyses further suggest that, there are two principal factors associated with climates variables and the model outputs. One of the factors indicate high loadings on Susceptible, Exposed and Infected human, while the other is more correlated with Susceptible and Recovered humans. However, both factors reveal the inverse correlation between Susceptible-Infected and Susceptible-Recovered humans respectively. Through the spectrum analysis, we notice a strong annual cycle of malaria incidence over the province and ascertain a dominant of one year periodicity. Consequently, our findings indicate that an average of 0 to 120-day lag is generally noted over the study period, but the 120-day lag is more associated with temperature than rainfall. This is consistence with other results obtained from our analyses that malaria transmission is more tightly coupled with temperature than with rainfall in KwaZulu-Natal province.

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Risk of Plasmodium falciparum infection in south-west Burkina Faso - potential impact of expanding eligibility for seasonal malaria chemoprevention

10.21203/rs.3.rs-900546/v1 ◽

2021 ◽

Author(s):

Anne L Wilson ◽

Steve W Lindsay ◽

Alfred Tiono ◽

Jean Baptiste Yaro ◽

Hilary Ranson ◽

...

Keyword(s):

Risk Factors ◽

Plasmodium Falciparum ◽

Burkina Faso ◽

Malaria Transmission ◽

Malaria Control ◽

Control Measures ◽

Sub Saharan Africa ◽

South West ◽

Seasonal Malaria Chemoprevention ◽

The Impact

Abstract Background Burkina Faso has one of the highest malaria burdens in sub-Saharan Africa despite the mass deployment of insecticide-treated nets (ITNs) and use of seasonal malaria chemoprevention (SMC) in children aged up to 5 years. Identification of risk factors for Plasmodium falciparum infection in rural Burkina Faso could help to identify and target malaria control measures. Methods A cross-sectional survey of 1,199 children and adults was conducted during the peak malaria transmission season in south-west Burkina Faso in 2017. Logistic regression was used to identify risk factors for microscopically confirmed P. falciparum infection. A malaria transmission dynamic model was used to determine the impact on malaria cases averted of administering SMC to children aged 5–15 year old. Results P. falciparum prevalence was 32.8% in the study population. Children aged 5 to < 10 years old were at 3.74 times the odds (95% CI = 2.68–5.22, p < 0.001) and children aged 10 to 15 years old at 3.14 times the odds (95% CI = 1.20–8.21, p = 0.02) of P. falciparum infection compared to children aged less than 5 years old. Administration of SMC to children aged up to 10 years is predicted to avert an additional 57 malaria cases per 1000 population per year (9.4% reduction) and administration to children aged up to 15 years would avert an additional 89 malaria cases per 1000 population per year (14.6% reduction) in the Cascades Region, assuming coverage of pyrethroid-piperonyl butoxide ITNs. Conclusion Malaria infections were high in all age strata, although highest in children aged 5 to 15 years, despite roll out of core malaria control interventions. Given the burden of infection in school-age children, extension of the eligibility criteria for SMC could help reduce the burden of malaria in Burkina Faso and other countries in the region.

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Global Stability of Malaria Transmission Dynamics Model with Logistic Growth

Discrete Dynamics in Nature and Society ◽

10.1155/2018/5759834 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Abadi Abay Gebremeskel

Keyword(s):

Sensitivity Analysis ◽

Global Stability ◽

Malaria Transmission ◽

Equilibrium Points ◽

Transmission Dynamics ◽

Logistic Growth ◽

Asymptotically Stable ◽

Dynamics Model ◽

Globally Asymptotically Stable ◽

The Impact

Mathematical models become an important and popular tools to understand the dynamics of the disease and give an insight to reduce the impact of malaria burden within the community. Thus, this paper aims to apply a mathematical model to study global stability of malaria transmission dynamics model with logistic growth. Analysis of the model applies scaling and sensitivity analysis and sensitivity analysis of the model applied to understand the important parameters in transmission and prevalence of malaria disease. We derive the equilibrium points of the model and investigated their stabilities. The results of our analysis have shown that if R0≤1, then the disease-free equilibrium is globally asymptotically stable, and the disease dies out; if R0>1, then the unique endemic equilibrium point is globally asymptotically stable and the disease persists within the population. Furthermore, numerical simulations in the application of the model showed the abrupt and periodic variations.

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Optimising systemic insecticide use to improve malaria control

BMJ Global Health ◽

10.1136/bmjgh-2019-001776 ◽

2019 ◽

Vol 4 (6) ◽

pp. e001776 ◽

Cited By ~ 1

Author(s):

Hannah R Meredith ◽

Luis Furuya-Kanamori ◽

Laith Yakob

Keyword(s):

Vector Control ◽

Malaria Transmission ◽

Drug Administration ◽

Mass Drug Administration ◽

Companion Animals ◽

Malaria Vectors ◽

Systemic Insecticide ◽

Blood Concentrations ◽

Systemic Insecticides ◽

The Impact

BackgroundLong-lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that overdependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability.MethodsHere, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through mathematical model simulation.ResultsThe review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations.ConclusionsThese findings will provide a guide for investigating and applying different systemic insecticides to achieve more effective and sustainable control of malaria transmission.

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The Impact of 3 Years of Targeted Indoor Residual Spraying With Pirimiphos-Methyl on Malaria Parasite Prevalence in a High-Transmission Area of Northern Zambia

American Journal of Epidemiology ◽

10.1093/aje/kwz107 ◽

2019 ◽

Vol 188 (12) ◽

pp. 2120-2130 ◽

Cited By ~ 3

Author(s):

Marisa A Hast ◽

Mike Chaponda ◽

Mbanga Muleba ◽

Jean-Bertin Kabuya ◽

James Lupiya ◽

...

Keyword(s):

Malaria Transmission ◽

Malaria Control ◽

Malaria Parasite ◽

Control Measure ◽

Indoor Residual Spraying ◽

Parasite Prevalence ◽

Organophosphate Insecticide ◽

Malaria Burden ◽

Pirimiphos Methyl ◽

The Impact

Abstract Malaria transmission in northern Zambia has increased in the past decade, despite malaria control activities. Evidence-based intervention strategies are needed to effectively reduce malaria transmission. Zambia’s National Malaria Control Centre conducted targeted indoor residual spraying (IRS) in Nchelenge District, Luapula Province, from 2014 to 2016 using the organophosphate insecticide pirimiphos-methyl. An evaluation of the IRS campaign was conducted by the Southern Africa International Centers of Excellence for Malaria Research using actively detected malaria cases in bimonthly household surveys carried out from April 2012 to July 2017. Changes in malaria parasite prevalence after IRS were assessed by season using Poisson regression models with robust standard errors, controlling for clustering of participants in households and demographic, geographical, and climatological covariates. In targeted areas, parasite prevalence declined approximately 25% during the rainy season following IRS with pirimiphos-methyl but did not decline during the dry season or in the overall study area. Within targeted areas, parasite prevalence declined in unsprayed households, suggesting both direct and indirect effects of IRS. The moderate decrease in parasite prevalence within sprayed areas indicates that IRS with pirimiphos-methyl is an effective malaria control measure, but a more comprehensive package of interventions is needed to effectively reduce the malaria burden in this setting.

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