Common Malaria Treatments

Introduction

Malaria is a mosquito-borne parasitic disease that causes high fever, severe chills, and sweating. [Focus, 2023] In medieval Italian "mal'aria," means "bad air", such that may coincide with mosquito habitat which includes swamps and marshes. [Boualam, 2021] It is spread by unicellular parasites of the genus Plasmodium. The infection is spread to people through the bite of Anopheles mosquitoes. [CDC, 2023]. At least 30 Anopheles species serve as vectors of human disease. [NIAID, 2016]

Malaria is mostly found in tropical countries. In 2021, nearly half of the world's population was at risk of malaria. That year, there were an estimated 247 million cases of malaria worldwide. The estimated number of malaria deaths stood at 619,000 in 2021. [WHO, 2023] The WHO African Region carries a disproportionately high share of the global malaria burden. In 2021, the Region was home to 95% of malaria cases and 96% of malaria deaths5. Children under 5 accounted for about 80% of all malaria deaths in the Region. [WHO, 2023]

Plasmodium - the causative agent of malaria

There are five main species of the Plasmodium parasite that can infect humans and cause malaria: [Stanford, 2019] Plasmodium falciparum is the deadliest malaria parasite and the most prevalent on the African continent [WHO, 2023]

Plasmodium vivax causes less serious illness, but the parasites can remain dormant in the liver for many months, known as hypnozoites during this time, causing a reappearance of symptoms months or even years later. [Adekunle, 2015] It is the dominant malaria parasite in most countries outside of sub-Saharan Africa.

P. malariae and P. ovale (including two subspecies) also infect humans. A study published in 2021 found that the pooled prevalence of P. malariae and P. ovale spp. were 2.01% and 0.77% respectively. [Hawadak]

Plasmodium knowlesi is a parasite that causes malaria in humans and other primates. [Collins, 2012] It is found throughout Southeast Asia, including Indonesia, Philippines, Vietnam, Cambodia, Laos, Thailand, and Myanmar. Furthermore, it is the most common cause of human malaria in Malaysia. [Hussin, 2020]

P. knowlesi is principally a primate malaria, while the exact proportion of infections in primates (various Old World monkeys) versus humans is not known. Approximately two-thirds of human P. knowlesi infections were of the long-tailed macaque type, and one-third were of the pig-tailed-macaque type, with relative proportions varying across the different sites. [Divis, 2015]

Monkey-to-human transmission is the main infection pathway, rather than human-to-human transmission. [Kotepui, 2020] Indeed, the majority of P. knowlesi infections likely occur in primates, with humans becoming infected through contact with these primates or their habitats. [Davidson, 2019]

Common Malaria Treatments

Chloroquine/ Hydroxychloroquine

Chloroquine/ hydroxychloroquine is a preferred medication primarily used to prevent and treat malaria in areas where malaria remains sensitive to its effects. It is usually used in combination with another antimalarial medicine to increase the effectiveness. [Mayo, 2023] [Merative, 2023]

It can also be used for prevention of malaria through pretravel dosing. Chloroquine is taken one to two weeks before traveling to an area of endemic malaria. [Kane, 2012] This helps to acclimatise the body, monitor for a reaction and provide time to alter the medication if there is a problem.

To prevent any delayed development of the disease it is recommended to keep taking chloroquine for 4 weeks after leaving an endemic area.

In many parts of the world, parasites have become resistant to Chloroquine, and the drug is no longer an effective treatment. [Kayiba, 2020] In such cases, a combination with a different or additional medication may be required. Always consult with a healthcare provider for the most appropriate treatment options.

Other medications

Other medications to treat malaria include quinine sulphate, mefloquine, atovaquone, proguanil, artemether / lumefantrine, doxycycline, primaquine, and Tafenoquine. [PHAC, 2014]

Conclusion

In conclusion, malaria, a mosquito-borne parasitic disease caused by Plasmodium parasites, remains a significant global health concern, especially in tropical countries. The term "mal'aria," meaning "bad air" in medieval Italian, reflects its historical association with mosquito habitats like swamps and marshes. Anopheles mosquitoes transmit the infection to humans, and at least 30 species of Anopheles serve as vectors.

The prevalence of malaria is substantial, with almost half of the world's population at risk in 2021, resulting in an estimated 247 million cases and 619,000 deaths. The WHO African Region bears a disproportionate burden, accounting for 95% of cases and 96% of deaths, with children under 5 representing 80% of fatalities.

Plasmodium, the causative agent, includes various species. Plasmodium falciparum is the deadliest, prevalent in Africa, while Plasmodium vivax, dominant outside sub-Saharan Africa, can cause relapses due to dormant parasites. Other species like P. malariae, P. ovale, and P. knowlesi also infect humans.

P. knowlesi, common in Southeast Asia, particularly Malaysia, is primarily a primate malaria. Humans can become infected through contact with primates and their habitats, which becomes increasingly common through urbanisation. Common treatments like chloroquine/ hydroxychloroquine, once effective, face challenges due to widespread resistance, necessitating alternative medications.

Chloroquine is a common drug for prevention and treatment, with pretravel dosing and post-travel continuation. However, resistance has led to the need for diverse antimalarial medications, including quinine sulfate, mefloquine, atovaquone, proguanil, artemether/lumefantrine, doxycycline, primaquine, and tafenoquine. Regular consultation with healthcare providers is crucial due to evolving resistance patterns and varying regional contexts.

REFERENCES

Adekunle, Adeshina I., et al. "Modeling the dynamics of Plasmodium vivax infection and hypnozoite reactivation in vivo." PLOS Neglected Tropical Diseases, vol. 9, no. 3, 17 Mar. 2015, https://doi.org/10.1371/journal.pntd.0003595.

Boualam, Mahmoud A., et al. "Malaria in Europe: A Historical Perspective." Frontiers in Medicine, vol. 8, 2021, Article 691095, 30 June 2021. https://doi.org/10.3389/fmed.2021.691095.

CDC. "Life Cycle of Anopheles Species Mosquitoes." Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 24 Aug. 2023, www.cdc.gov/mosquitoes/about/life-cycles/anopheles.html.

Collins, William E. "Plasmodium knowlesi: A Malaria Parasite of Monkeys and Humans." Annual Review of Entomology, vol. 57, 2012, pp. 107-121. PMID: 22149265, doi:10.1146/annurev-ento-121510-133540.

Davidson, Gael et al. "Defining the ecological and evolutionary drivers of Plasmodium knowlesi transmission within a multi-scale framework." Malar J, vol. 18, no. 1, 2019, p. 66. doi: 10.1186/s12936-019-2693-2.

Divis, Paul C. S., et al. "Admixture in Humans of Two Divergent Plasmodium knowlesi Populations Associated with Different Macaque Host Species." PLoS Pathogens, vol. 11, no. 5, 2015, e1004888. DOI: 10.1371/journal.ppat.1004888.

Focus Medica. "Malaria." Edited by Rakshith Bharadwaj, MSN, Microsoft, 13 June 2023, www.msn.com/en-us/health/condition/Malaria/hp-Malaria?source=conditioncdx.

Hawadak, Joseph, et al. "Global Trend of Plasmodium malariae and Plasmodium ovale spp. Malaria Infections in the Last Two Decades (2000-2020): A Systematic Review and Meta-Analysis." Parasites & Vectors, vol. 14, no. 1, 2021, pp. 297. DOI: 10.1186/s13071-021-04797-0.

Hussin, Narwani, et al. "Updates on Malaria Incidence and Profile in Malaysia from 2013 to 2017." Malaria Journal, vol. 19, no. 1, 2020, p. 55. doi: 10.1186/s12936-020-3135-x.

Kane, Megan, et al. "Hydroxychloroquine Therapy and G6PD Genotype." Edited by Adriana J. Malheiro, editors. Medical Genetics Summaries, National Center for Biotechnology Information (US), 2012. Web. 2 May 2023.

Kayiba, Nadine Kalenda et al. "The landscape of drug resistance in Plasmodium falciparum malaria in the Democratic Republic of Congo: a mapping systematic review." Trop Med Health, vol. 51, no. 1, 2023, p. 64. doi: 10.1186/s41182-023-00551-7.

Kotepui, Manas, et al. "Prevalence of severe Plasmodium knowlesi infection and risk factors related to severe complications compared with non-severe P. knowlesi and severe P. falciparum malaria: a systematic review and meta-analysis." Infect Dis Poverty, vol. 9, no. 1, 2020, p. 106. doi: 10.1186/s40249-020-00727-x.

Mayo. "Malaria." Mayo Clinic, Mayo Foundation for Medical Education and Research, 9 Feb. 2023.  www.mayoclinic.org/diseases-conditions/malaria/diagnosis-treatment/drc-20351190.Merative. "Chloroquine (Oral Route) Proper Use." Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2023, www.mayoclinic.org/drugs-supplements/chloroquine-oral-route/proper-use/drg-20062834.

Merative. "Chloroquine (Oral Route) Proper Use." Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2023, www.mayoclinic.org/drugs-supplements/chloroquine-oral-route/proper-use/drg-20062834.

NIAID. "Malaria Parasite, Mosquito, and Human Host." National Institute of Allergy and Infectious Diseases, U.S. Department of Health and Human Services, 4 Mar. 2016, www.niaid.nih.gov/diseases-conditions/malaria-parasite.

PHAC. "Drugs (Generic and Trade Name) for the Treatment and Prevention of Malaria." Canada.Ca, Public Health Agency of Canada, 3 June 2014, www.canada.ca/en/public-health/services/travel-health/drugs-generic-trade-name-treatment-prevention-malaria.html.

Stanford Medecine. "Types of Malaria Parasites." Stanford Health Care (SHC) - Stanford Medical Center, Stanford Medicine, 15 Jan. 2019, stanfordhealthcare.org/medical-conditions/primary-care/malaria/types.html.Stanford Medecine. "Types of Malaria Parasites." Stanford Health Care (SHC) - Stanford Medical Center, Stanford Medicine, 15 Jan. 2019, stanfordhealthcare.org/medical-conditions/primary-care/malaria/types.html.

WHO. "Malaria." 29 March 2023, https://www.who.int/news-room/fact-sheets/detail/malaria.

About The Author

David  Orchard-Webb, Ph.D., is a technical writer with broad interests including  health & technology writing, plus extensive training and knowledge of  biomedicine and microbiology. My Ph.D. and postdoc were in oncology and  developing cancer medicines. I provide technical medical and other writing  services for projects ranging from “knowledge automation” to pure pharma, to  food safety, to the history of science, and everything in between. I also  provide white papers, ebooks, meta-analysis reviews, editing, consulting,  business, and market research-related activities in biomedicine, technology,  and health. In addition to its well-known role in the development of  medicines, I am a big believer in biotechnology’s ability to revolutionize  industries such as food-tech, agtech, textiles & fashion.