By Dr. Derick Pasternak, Malaria Partners International Malaria Science & Research Coordinator
With the proliferation of web-based publications, information on biomedical sciences is becoming much more broadly-based, but also fragmented. It is no longer sufficient to study the National Library of Medicine website, nor the once limited number of general scientific publications (Science, Nature, etc.). The result is that at times articles that may have been missed will show up in the secondary references in recent publications. Such is the case of an article in this report, seen below in the Prevention category. Another necessary consequence is that of the articles published one has to make certain choices, so that this summary of the literature remain useful to the reader.
Prevention
Two articles by Wadi and colleagues (one from 2019) discuss the implications of finding agents that prevent the transmission of malaria. They are : Recent Advances in Transmission-Blocking Drugs for Malaria Elimination, Future Med Chem 2019 Dec;11(23):3047-3088. doi: 10.4155/fmc-2019-0225 and Malaria Transmission-Blocking Drugs: Implications and Future Perspectives, Future Med Chem 2020 Jun;12(11):1071-1101. doi: 10.4155/fmc-2020-0026. Abstracts are available.
Troye-Blomberg and colleagues summarize discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria in What Will Studies of Fulani Individuals Naturally Exposed to Malaria Teach Us About Protective Immunity to Malaria? Scand J Immunol, 2020 Jul 11;e12932. doi: 10.1111/sji.12932.
Malaria in the Pregnant Traveler, J Travel Med, 2020 Jul 14;27(4) discusses the imperative of prevention strategies of pregnant travelers in view of the risk of severe illness and pregnancy complications. The 9-page article is available for review.
In view of the recent Malaria Partners International interest in working in the Gambia, Knudsen et al.’s article, Measuring Ventilation in Different Typologies of Rural Gambian Houses: A Pilot Experimental Study, Malaria Journal 2020 vol. 19, Article # 273, which discusses implications of bed-net use, is of interest.
Bromeliad malaria is primarily a condition in the Caribbean and surrounding areas. It is spread by a subgenus of Anopheles. Control of these vectors is discussed in Multini et al., Neotropical Anopheles (Kerteszia) Mosquitoes Associated with Bromeliad-Malaria Transmission in a Changing World, Acta Trop, 2020 May;205:105413.
Diagnosis
Mbanefo & al.’s paper, Evaluation of Malaria Diagnostic Methods as a Key for Successful Control and Elimination Programs, Trop Med Infect Dis, 2020 Jun 19;5(2):102, reviews and highlights the importance of accurate, sensitive and affordable diagnostic methods in the fight against malaria. “Currently used diagnostic methods include microscopy, rapid diagnostic tests (RDT), and polymerase chain reaction (PCR). Upcoming methods were identified as loop-mediated isothermal amplification (LAMP), nucleic acid sequence-based amplification (NASBA), isothermal thermophilic helicase-dependent amplification (tHDA), saliva-based test for nucleic-acid amplification, saliva-based test for Plasmodium protein detection, urine malaria test (UMT), and transdermal hemozoin detection. RDT, despite its increasing false negative, is still the most feasible diagnostic test because it is easy to use, fast, and does not need expensive equipment. Noninvasive tests that do not require a blood sample, but use saliva or urine, are some of the recent tests under development that have the potential to aid malaria control and elimination.” The article is 15 pages long; it, and its abstract are available.
Plasmodium malariae infection does not carry implications of high mortality; nonetheless, as reported by Kotepui M, & al., Global Prevalence and Mortality of Severe Plasmodium malariae Infection: A Systematic Review and Meta-Analysis, Malaria Journal 2020, vol. 19, Article # 274, some of the complications (anemia, kidney and lung damage) can be just as frequent with P. malariae as with P. falciparum.
Screening for malaria and treatment if appropriate in prenatal care in Tanzania are discussed by Walker and colleagues, Modelling the Incremental Benefit of Introducing Malaria Screening Strategies to Antenatal Care in Africa, Nature Communications 2020, vol. 11, Article # 3799. We have both the abstract and the article.
Two recent articles appear to draw conclusions that may or may not be consistent with each other about coexisting malaria and Burkitt’s lymphoma in East Africa. While Redmond, & al., Endemic Burkitt Lymphoma: A Complication of Asymptomatic Malaria in Sub-Saharan Africa Based on Published Literature and Primary Data from Uganda, Tanzania, and Kenya, Malaria Journal 2 020, vol. 19, Article # 239, conclude on the basis of epidemiologic data that children with asymptomatic parasitemia/antigenemia may be the population at highest risk of endemic Burkitt’s Lymphoma (eBL). On the other hand, Quintana and colleagues argue that exposure to P. falciparum appears to be essentially a prerequisite to the development of eBL, whereas other types of malaria parasites that infect humans have no impact. [They] summarize how malaria exposure may precipitate the malignant transformation of a B-cell clone that leads to eBL, and propose an explanation for why P. falciparum uniquely has this capacity. See Endemic Burkitt Lymphoma – An Aggressive Childhood Cancer Linked to Plasmodium falciparum Exposure, But Not to Exposure to Other Malaria Parasites, APMIS, 2020 Feb;128(2):129-135. doi: 10.1111/apm.13018. The entire former article and both abstracts are in our Library.
Treatment
“The deployment of artesunate for severe malaria and the artemisinin combination therapies (ACTs) for uncomplicated malaria has been a major advance in antimalarial therapeutics. These drugs have reduced treated mortality, accelerated recovery, and reduced treatment failure rates and transmission from the treated infection. Artemisinin derivatives remain highly effective against falciparum malaria in most malaria endemic areas but significant resistance has emerged in … Southeast Asia. Resistance to artemisinins was followed by resistance in the ACT partner drugs, and fit multidrug resistant parasite lineages have now spread widely across the region. … As new drugs will not become widely available in the near future, active measures to preserve the current antimalarials should be given the highest priority.” In addition to this article, Hanboonkunupakam and White Advances and Roadblocks in the Treatment of Malaria, Br J Clin Pharmacol, 2020 Jul 12, doi: 10.1111/bcp.14474, two articles cited under Basic Research deal with artemisinin resistance, which will presumably not be confined to Asia for long.
“Despite potent anti-malarial treatment, mortality rates associated with severe falciparum malaria remain high. To attempt to improve outcome, several trials have assessed a variety of potential adjunctive therapeutics, however none to date has been shown to be beneficial. This may be due, at least partly, to the therapeutics chosen and clinical trial design used. [Varo et al.] highlight three themes that could facilitate the choice and evaluation of putative adjuvant interventions for severe malaria, paving the way for their assessment in randomized controlled trials.” Clinical Trials to Assess Adjuvant Therapeutics for Severe Malaria, Malaria Journal Jul 2020, vol. 19, Article # 268. The abstract is available.
Campaigns
WHO published two major pamphlets: The Potential Impact of Health Service Disruptions on the Burden of Malaria: A Modeling Analysis for Countries in Sub-Saharan Africa (44 pages) and Tailoring Malaria Interventions in the COVID-19 Response (34 pages), as well as an information sheet, WHO Urges Countries to Move Quickly to Save Lives from Malaria in Sub-Saharan Africa. These issues are also reflected in Chiodini J, COVID-19 and the Impact on Malaria, Travel Med and Inf Dis, 2020 35:101758. All four publications are available in their entirety.
Basic Research
“As the Plasmodium parasite does not enter the brain, but resides inside erythrocytes and are confined to the lumen of the brain’s vasculature, the neuropathogenesis leading to these neurologic sequelae is unclear and under-investigated. Interestingly, postmortem [cerebral malaria] pathology differs in brain regions, …” The article, Schiess & al., Pathophysiology and Neurologic Sequelae of Cerebral Malaria, Malaria Journal Jul 2020, vol. 19, Article # 266, focuses primarily on this conundrum.
Two articles on artemisinin resistance report on investigations of the basic mechanisms of that resistance. They are:
Imwong et al., Molecular Epidemiology of Resistance to Antimalarial Drugs in the Greater Mekong Subregion: An Observational Study, Lancet Inf Dis 2020 JU 14, https://doi.org/10.1016/ S1473-3099(20)30228-0 and
Blank BR & al., Antimalarial Trioxolanes with Superior Drug-Like Properties and In Vivo Efficacy, ACS Infect Dis 2020 Jul 10;6(7):1827-1835. doi: 10.1021/acsinfecdis.0c00064.