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The profusion of articles about malaria continues.  Despite the fact that over 90% of all malaria infections occur in Africa, fewer than half of the articles relate to that continent, although the very large component of basic science articles distort the statistic.  This month, because of the large volume of articles about prevention and epidemiology, only a few basic science articles are cited.  If there is a demand for more, please let me know.

Prevention:

One of two interesting articles about vector control is Ekoka E & al., 20-Hydroxyecdysone (20E) Signaling as a Promising Target for the Chemical Control of Malaria Vectors, Parasit Vectors, 2021 Jan 29;14(1):86.  doi: 10.1186/s13071-020-04558-5.  The second is Hellewell J & al., Assessing The Impact of Low-Technology Emanators Alongside Long-Lasting Insecticidal Nets to Control Malaria, Philos Trans R Soc Lond B Biol Sci, 2021 Feb 15;376(1818):20190817. doi: 10.1098/rstb.2019.0817. Epub 2020 Dec 28  (article available). Both articles describes techniques that may be implemented to prevent mosquito bites that occur whenever individuals are necessarily abandoning bednets, even if the latter are used optimally.

Mahamar A & al., Effect of 4 Years of Seasonal Malaria Chemoprevention on the Acquisition of Antibodies to Plasmodium Falciparum Antigens in Ouelessebougou, Mali, Malar J, 2021 Jan 7;20(1):23.  doi: 10.1186/s12936-020-03542-9 (Article available) and Gilmartin C & al., Seasonal Malaria Chemoprevention in the Sahel Subregion of Africa: A Cost-Effectiveness and Cost-Savings Analysis, Lancet Glob Health, 2021 Feb;9(2):e199-e208. doi: 10.1016/S2214-109X(20)30475-7. These two articles recount the benefits of chemoprevention of malaria focused on the time of year when infections are most prevalent.

Nlinwe NO &al., Evaluation of Malaria Preventive Measures Among Adult Patients Attending the Bamendjou and Foumbot District Hospitals of the West Region of Cameroon, Malar J, 2021 Jan 22;20(1):60.  doi: 10.1186/s12936-021-03592-7 is a more general analysis confined to the Western (English-speaking) region of Cameroon.

The role of incorporating malaria prevention strategies in education is explored by Balami AD & al. in Improving Malaria Preventive Practices and Pregnancy Outcomes Through a Health Education Intervention: A Randomized Controlled Trial, Malar J, 2021 Jan 21;20(1):55. doi: 10.1186/s12936-021-03586-5 (article available). The education was provided in native (Hausa) language to this group of Nigerian women.  Results were said to be beneficial in the intervention versus the control group, though were measured by process variables (use of bednets, etc.) with the exception of a single outcome variable (drop in hematocrit).

Among several vaccine-related articles we find Stanisic DI & McCall MBB, Correlates of Malaria Vaccine Efficacy, Expert Rev Vaccines, 2021 Jan 27. doi: 10.1080/14760584.2021.1882309 (online ahead of print) and Suau R & al., RTS,S/AS01 E Malaria Vaccine Induces IgA Responses Against CSP and Vaccine-Unrelated Antigens in African Children in the Phase 3 Trial, Vaccine, 2021 Jan 22;39(4):687-698. doi: 10.1016/j.vaccine.2020.12.038. Epub 2020 Dec 25. Actually, the latter would also fit in the basic science category.

Not new, but an unusually interesting approach to prevention is described by Nevagi RJ & al. in Plasmodium Infection and Drug Cure for Malaria Vaccine Development, Expert Rev Vaccines, 2021 Jan 11.  doi: 10.1080/14760584.2021.1874923 (online ahead of print).  Given the limited efficacy of all vaccines developed so far, they describe the attempt to induce long-term immunity by purposely infecting and immediately vigorously treating individuals.

Diagnosis:

Abuaku B & al. conclude in Malaria Parasitaemia and mRDT Diagnostic Performances Among Symptomatic Individuals in Selected Health Care Facilities Across Ghana, BMC Public Health, 2021 Jan 28;21(1):239. doi: 10.1186/s12889-021-10290-1 (article available) that “HRP2-based mRDTs [malaria rapid diagnostic tests] remain effective diagnostic tool in the management of suspected uncomplicated malaria in the country.”

According to Korzeniewski K &al., Prevalence of Asymptomatic Malaria Infections in Seemingly Healthy Children, the Rural Dzanga Sangha Region, Central African Republic, Int J Environ Res Public Health, 2021 Jan 19;18(2):814. doi: 10.3390/ijerph18020814. (article available) there is “high prevalence of asymptomatic malaria infections in south-west CAR.”  These amounted to 32-41% of asymptomatic children ages 1-15 tested with rapid diagnostic tests (RDTs). “RDTs seem to be a useful tool for the detection of Plasmodium falciparum in areas with limited possibilities of using other diagnostic methods, such as light microscopy and molecular biology.”

Treatment:

In a very large meta-analysis (article available), Blanshard A and Hine P review the efficacy of two-drug treatment of uncomplicated P. falciparum infection for travelers and for those living in endemic areas who are unable to take artesunates. The article is Atovaquone-Proguanil for Treating Uncomplicated Plasmodium falciparum Malaria, Cochrane Database Syst Rev, 2021 Jan 15;1:CD004529.doi: 10.1002/14651858.CD004529.pub3.

Guidelines for treatment of malaria in pregnancy are the topic of Al Khaja KAJ & Sequeira RP, Drug Treatment and Prevention of Malaria in Pregnancy: A Critical Review of the Guidelines, Malar J 2021 Jan 23;20(1):62. doi: 10.1186/s12936-020-03565-2. They reviewed 35 updated national guidelines and the President’s Malaria Initiative (PMI), available in English language.  The complex description of their conclusions includes the fact that some of the guidelines are significantly less comprehensive than others, especially in situations that require caution.

Continuing the search for naturally occurring malaria-controlling substances, Imran IZ & al., Bioactivity-Directed Evaluation of Fruit of Kigelia africana (Lam.) Benth. Used In Treatment of Malaria in Iwo, Nigeria, J Ethnopharmacol, 2021 Mar 25;268: 113680.  doi: 10.1016/j.jep.2020.113680. Epub 2020 Dec 8 conclude that “ The use of herbs and medicinal plants either singly or in combination for the treatment of malaria among the people of Iwo community in Nigeria is still well practiced. …. Kigelia africana has antiplasmodial activity in the order of fruit > root > leaf > stem bark.”

Campaigns:

The Prevention heading above includes articles relating to the seasonality of malaria in certain regions. Sacko A et al. turn to use of this knowledge in campaigns.  Results are reported in Evolution of Malaria Incidence in Five Health Districts, in the Context of the Scaling Up of Seasonal Malaria Chemo-prevention, 2016 to 2018, in Mali, Int J Environ Res Public Health, 2021 Jan 19;18(2):840. doi: 10.3390/ijerph18020840 (article available).  They report that as a result, a “decrease in incidence was observed in children under five years old in 2017 and 2018 compared to 2016.”

Shi B & al., Accessing the Syndemic of COVID-19 and Malaria Intervention in AfricaInfect Dis Poverty, 2021 Jan 7;10(1):5. doi: 10.1186/s40249-020-00788-y is yet another report on the effect that the pandemic has had on malaria control, specifically in Ethiopia, Nigeria, Tanzania, and Zambia.

Epidemiology:

Another meta-analysis of published articles covers the subject of patients co-infected with the HIV virus and malaria.  It is reported by Obebe OO & Falohun OO as Epidemiology of Malaria Among HIV/AIDS Patients in Sub-Saharan Africa: A Systematic Review and Meta-Analysis of Observational Studies, Acta Trop, 2021 Mar;215:105798. doi: 10.1016/j.actatropica.2020 105798. Epub 2020 Dec 17. For example, “HIV infected patients with low CD4 + T cell count (CD4 < 200 cells/mm3) were 2.19 times more likely to become infected with malaria than those with high CD4 + T cell count (CD4 ≥ 200 cells/mm3) (pooled odds ratio (POR): 2.19 (95%CI 1.20;3.98), while patients on antiretroviral therapy (POR): 0.37 (0.23; 0.59), and in WHO clinical stages I and II (POR): 0.64 (0.28; 1.46), had a lower odds of [being] infected with malaria.”

In another seasonally and regionally oriented study focused on Zambia, Lubinda J & al argue for targeted seasonally-sensitive malaria chemoprevention programs. The report, Near-Term Climate Change Impacts on Sub-National Malaria Transmission, Sci Rep, 2021 Jan 12;11(1):751.  doi: 10.1038/s41598-020-80432-9 (article available) they “found substantial sub-national near-term variations and significant associations with malaria incidence-trends. Significant spatio-temporal shifts in DTR [daily temperature ranges]/environmental predictors influenced malaria incidence-rates, even in areas with declining trends.”

A somewhat similar focus, using data from Uganda and Southern Ethiopia, respectively, is the subject of Okiring J & al., Relationships Between Test Positivity Rate, Total Laboratory Confirmed Cases of Malaria, and Malaria Incidence in High Burden Settings of Uganda: An Ecological Analysis,  Malar J, 2021 Jan 13;20(1):42.  doi: 10.1186/s12936-021-03584-7 and Molla E & al., Past Eight-Year Malaria Data in Gedeo Zone, Southern Ethiopia: Trend, Reporting-Quality, Spatiotemporal Distribution, and Association with Socio-Demographic and Meteorological Variables, BMC Infect Dis, 2021 Jan 21;21(1):91.  doi: 10.1186/s12879-021-05783-8. Both articles are available.

Millogo O and colleagues report on the ability of a health system to deal with malaria in Constructing a Malaria-Related Health Service Readiness Index and Assessing Its Association with Child Malaria Mortality: An Analysis of the Burkina Faso 2014 SARA Data, BMC Public Health, 2021 Jan 5;21(1):20.  doi: 10.1186/s12889-020-09994-7 (article available).

According to Taylor C & al.,”[e]stimating severe malaria cases through population-based surveys allows countries to estimate severe malaria across time and to compare with other countries. Having a population-level estimate of severe malaria cases helps further our understanding of the burden and epidemiology of severe malaria.”  Their article is Estimating the Fraction of Severe Malaria among Malaria-Positive Children: Analysis of Household Surveys in 19 Malaria-Endemic Countries in Africa, Am J Trop Med Hyg, 2021 Feb 1;tpmd201351.  doi: 10.4269/ajtmh.20-1351 (online ahead of print).

Exposure to malaria in the US is the subject of a study by Dye-Braumuller K, and Kanyangarara M, Malaria in the USA: How Vulnerable Are We to Future Outbreaks? Curr Trop Med Rep 2021 Jan 14;1-9.  doi: 10.1007/s40475-020-00224-z (article available).  They conclude that “multiple risk factors suggest that local malaria outbreaks in the USA will continue to pose a public health threat due to large numbers of international travelers from endemic areas, multiple Anopheles spp. capable of transmitting the parasite, and unsatisfactory vector-borne disease outbreak preparedness.”

Basic Research:

De-Oliveira ACAX, & Paumgartten FJR, Malaria-induced Alterations of Drug Kinetics and Metabolism in Rodents and Humans, Curr Drug Metab, 2021 Jan 1  doi: 10.2174/ 1389200221999210101232057  (online ahead of print).

Halikazemian M & al., Battleground Midgut: The Cost to the Mosquito for Hosting the Malaria Parasite, Biol Cell,  2021 Feb;113(2):79-94.  doi: 10.1111/boc.202000039. Epub 2020 Nov 23.

Tiwari S & al., Redox Interactome in Malaria Parasite Plasmodium falciparum, Parasitol Res, 2021 Feb;120(2):423-434.  doi: 10.1007/s00436-021-07051-9. Epub 2021 Jan 18.

Patel PN, Tolia N, Structural Vaccinology of Malaria Transmission-Blocking Vaccines, Expert Rev Vaccines 2021 Jan 19;1-16. doi: 10.1080/14760584.2021.1873135 (online ahead of print).