By Samara Macrae
Published 11:18 EST, Thurs October 21st, 2021
Introduction:
Epidemic is defined by the Oxford English Dictionary as: “a widespread occurrence of an infectious disease in a community at a particular time”. Malaria is classed as an epidemic, currently affecting over 100 countries predominantly in the tropical regions – and is the fourth highest cause of death in children under the age of five years1. Despite the extensive death and casualty toll, as well as the havoc wreaked on socio-economic conditions in areas of outbreak, these epidemics receive significantly less media coverage and humanitarian attention as they are affecting the developing world. Even after the original health threat has been managed, developing countries continue to face serious long term effects compared to more economically developed ones. This can be shown by what activists refer to as the ‘10/90 Gap’: this is the idea that only 10% of global health research is allocated towards diseases responsible for 90% of preventable deaths globally. Diseases that make up this 10% can be referred to as ‘neglected diseases’, typically because they predominantly affect lower-income countries where poverty and malnutrition are rife – and so exacerbate the spread of such life-threatening communicable diseases. According to the World Health Organisation, 45% of the ‘disease burden’ in the most under-developed and poorest countries is derived from poverty. Therefore, these diseases cannot merely be treated medically, but the deeper social problems in the regions need to be tackled as well.
Malaria is an example of a disease which can be understated and disregarded for its impact due to societal prejudice against less economically developed regions of the world. Malaria mostly affects tropical regions, including (but not limited to) large zones of Africa, particularly in sub-Saharan Africa, South America, the Dominican Republic, the Caribbean and Central America2. While there are recorded cases of malaria in developed countries such as the USA and the UK, this is almost exclusively the result of travellers returning from holiday from countries where malaria is prevalent. 3Malaria disproportionately affects the continent of Africa and, in 2019, 94% of malaria cases and deaths as a result of this disease were in the African continent. Nearly 50% of the global population was at risk of contracting malaria in 2019, and that same year there were approximately 229 million recorded cases of the disease across the world. Despite the fact that malaria is both curable and preventable, this disease has significantly less funding compared to diseases and conditions which disproportionately affect the developed world – such as obesity, which is the fifth most important risk factor for disease amongst developed countries. In 1986, the US spent approximately $39 billion on tackling obesity, and this rose to $190 billion by 20054.
How malaria affects the body:
Malaria is caused by a plasmodium, and there are five different parasite species which can spread malaria – the two most predominant species being P. falciparum and P. vivax3. The former is the main cause of malaria in Africa, south-east Asia, and the Pacific while the latter presents the greater threat in South and Central America. These species of plasmodium parasite are transmitted by an animal vector: the female Anopheles mosquito. In rarer instances, malaria can be transmitted by sharing unsterilised needles, via blood transfusion or from the mother to the foetus. When the female Anopheles mosquito takes a blood meal from a host who is infected with malaria, it will inject saliva into the host’s skin while sucking blood through its proboscis. This saliva acts as a form of antiseptic and is why it is difficult to notice when the mosquito is doing this. As the mosquito takes up this infected blood, the male and female gametes of the malaria-causing plasmodium will fuse in the mosquito’s stomach. Cell division will be carried out then, which will lead to the formation of thousands of immature malarial parasites – these parasites will then invade the salivary glands of the mosquito. This means that when the mosquito takes a blood meal from an uninfected host, it will inject its saliva – containing the plasmodium parasites – into the host’s skin. Thus, the parasites are then able to infect the host’s bloodstream and this results in the manifestation of the disease. One reason why the majority of malaria cases and deaths are in the continent of Africa is due to the long lifespan of the African vector species of female Anopheles mosquitoes. This means that the parasite has a longer time to develop inside the mosquito, and so more parasites can be produced.
Symptoms:
3The symptoms of malaria typically show 10 to 15 days after an individual is bitten by a mosquito vector. Some early symptoms can include a headache, fever, and chills – but these are all typically mild and so not necessarily immediately discernible as malaria. However, the severity of the disease soon increases, as failure to receive treatment within 24 hours of the first symptoms when infected by the P. falciparum parasite can mean that the disease progresses swiftly and often culminates in death. Severe cases of malaria can also include the following symptoms: severe anaemia, liver damage and multiple-organ failure. Children are the group most greatly affected by malaria, especially under the age of five years – and in 2019, 67% of all malaria deaths globally (approximately 274 000 people) were children below five years of age. Other high-risk groups of people are pregnant women, non-immune migrants/travellers and individuals with HIV or AIDS.
Prevention:
As malaria is transmitted by mosquito vectors, the most straightforward and accessible method of prevention is mosquito nets – which can be made more effective if treated with insecticide. This, in conjunction with personal use of insect repellent has been shown to reduce the risk of malarial infection by up to 80%5. Also, wearing clothing that limits skin exposure can help to reduce the chance of receiving a mosquito bite which could potentially be fatal. Individuals who are travelling to countries where there are cases of malaria can obtain medication to prevent them contracting the disease.
Malarial chemoprophylaxis is only available in European countries, and only for travellers to countries where malaria is prevalent – and not for the inhabitants of the areas affected6. Malarial chemoprophylaxis is classified into 3 groups in order to determine the most suitable drug for the individual. The drug recommended depends on factors such as duration of potential exposure, age, and climate of the destination.7 Antimalarial tablets can reduce the chances of becoming infected with malaria by approximately 90%. The main types of antimalarial medication are: atovaquone plus proguanil, doxycycline, mefloquine/larium and chloroquine plus proguanil. Chloroquine plus proguanil is still available for travellers but is rarely recommended now due to its ineffectiveness against P. falciparum but can still be prescribed if the individual is visiting an area where this plasmodium is less common, as in Sri Lanka.
Recently, there has been promising research into a new malaria vaccine, developed at the University of Oxford’s Jenner Institute. In a small clinical trial, involving 450 children, this vaccine showed up to 77% efficacy – a dramatic increase from the current vaccine’s efficacy8. Undoubtedly larger clinical trials are needed to ensure the safety and effectiveness of this vaccine, but surely this research should be pushed ahead – as the Covid-19 vaccines were – when millions of people die every year from malaria. This is not to dispute the urgent global need for vaccines against Covid-19, but surely when a disease is so widespread and life-threatening as malaria is it demands the same urgency to tackle the endless death toll each year. Yet this is not the case, and one key reason why is the fact that it mainly affects lower-income, under-developed countries.
9There is presently only one vaccine against malaria and has the brand name Mosquirix. It requires four injections but even then, only offers approximately 30% protection against severe malaria, and only for up to four years. This raises arguments as to whether this vaccine is cost efficient. Additionally, there are further concerns over the safety of this vaccine; in a clinical trial for Mosquirix, the children who had received the vaccine had a risk of contracting meningitis that was 10 times higher than the children who had received the placebo. While there is not sufficient evidence to show that causation, this does hinder the potential safety of this vaccine and has, as a result, impeded rollouts of it. The new vaccine for malaria could gradually replace Mosquirix, and can mean that more individuals are protected against this disease.
Treatment:
Malaria is a curable disease and is treated using antimalarial drugs. The most common of these drugs is Chloroquine phosphate, but unfortunately this treatment is gradually being rendered ineffective due to increasing resistance of malarial parasites to it. Another type of antimalarial drug treatment is Artemisinin-based combination therapies (ACTs); ACT is actually a combination of antimalarial drugs and is used mostly where there is resistance to chloroquine phosphate. Primaquine phosphate is another frequently used antimalarial drug, in addition to quinine sulfate with doxycycline10. Noticeably, many antimalarial drugs contain the word ‘quine’ or ‘quinine’, as they often contain quinine, which is a chemical compound naturally derived from the bark of the cinchona tree.
Currently the Mayo Clinic is carrying out a clinical trial entitled “A Study to Evaluate Intravenous Artesunate to Treat Severe Malaria in the United States”11, and this study hopes to make intravenous artesunate available for treatment in cases of severe malaria. As of yet, there are no publications for this clinical trial.
The global management of malaria:
Currently there are global initiatives attempting to end the spread of malaria. One such example is the Mekong Malaria Elimination (MME) programme organised by the World Health Organisation (WHO)12. The MME programme is working towards eliminating malaria in Myanmar, Cambodia, the Lao People’s Democratic Republic, China, Vietnam, and Thailand, and began in 2017 in response to the increasing ineffectiveness of specific antimalarial drugs as a result of drug-resistant malarial parasites. On the 3rd of November 2020, Cambodia committed to completely eradicating P. falciparum by 202313. Dr Li Ailan, who is the WHO Representative to Cambodia stated: “. Cambodia, being very close to the goal, can be the first country in the region to eliminate P. falciparum malaria, serving as a champion in the Greater Mekong Subregion.” As part of this auspicious commitment, three main interventions have been set out: the distribution of mosquito screens and nets, malaria screening involving weekly fever screening for each household – and any individual with a fever will be tested for malaria and then receive treatment if they are positive for the disease, and furthermore, improved preventive measures for travellers to areas which are at-risk of the spread of malaria.
Conclusion:
Arguably malaria, as a disease alone, is theoretically relatively easy to prevent and treat: through insecticides, mosquito nets, vaccinations and antimalarials. In reality, the countries most affected by this disease do not have sufficient funds to provide this, let alone tackle the deep-rooted causes of poverty, poor access to clean drinking water and sanitation infrastructure, and malnutrition in addition to food insecurity – which collectively establishes an environment in which diseases, like malaria, can reach levels of epidemic. There needs to be a greater collective, global effort to tackle so-called ‘poverty-related diseases’ like malaria, but also cholera, typhoid and diphtheria to name more, as there was with smallpox and as there is now with Covid-19. That is not to discriminate against developed countries using their funds to further research healthcare and medicine in their own countries – as this is essential for advancing medicine and understandably they want to improve healthcare in their own countries first and foremost. Furthermore, it is also not to say that wealthier nations should extensively increase the amount of aid they give to ‘fix’ the healthcare problems in other nations – but, when aid is given, it should perhaps be directed to try and address the larger and more long-term socio-economic problems that allow diseases to manifest.
When aid is given in order to reduce the spread of malaria in the worst-impacted regions, it should simultaneously be used to improve the conditions which allow the disease to manifest and become so widespread. However, simply providing money to ‘fix’ these socio-economic problems is not a straightforward answer – as it ignores the presence of factors such as corruption, debt and prioritising immediate humanitarian aid over the longer-term social problems which are more difficult to fix due to their longevity and severity. Referring back to the ‘10/90 Gap’, this balance between the funding of disease mainly affecting the developed world and the ‘neglected diseases’ more prevalent in the developing world needs to be readdressed. When globally the disease burden is significantly greater in less developed regions, more aid needs to be directed towards this rather than disproportionately towards diseases that are less widespread and prevalent which impact more developed regions.
There is no single, clear solution to the problem of malaria – and more broadly the ‘10/90 Gap’. However, it is undeniable that if malaria were as rampant across the developed world as it is presently in the developing world then there would undoubtedly be global upheaval to tackle this disease, and such a gap in funding would not be so significant.
Samara Macrae, Youth Medical Journal 2021
References:
1. Medscape: “What is the mortality rate of malaria?” – https://www.medscape.com/answers/221134-40790/what-is-the-mortality-rate-of-malaria
2. Travel Health Pro: “Malaria” – https://travelhealthpro.org.uk/disease/113/malaria
3. World Health Organisation: “Malaria Key Facts” – https://www.who.int/news-room/fact-sheets/detail/malaria
4. Harvard TH Chan; School of Public Health: “Obesity Prevention Source” – https://www.hsph.harvard.edu/obesity-prevention-source/obesity-consequences/economic/
5. Hill N, Lenglet A, Arnéz AM, Carneiro I. Plant based insect repellent and insecticide treated bed nets to protect against malaria in areas of early evening biting vectors: double blind randomised placebo controlled clinical trial in the Bolivian Amazon. BMJ. 2007;335(7628):1023.
6. European Centre for Disease Prevention and Control: “Facts about malaria” – https://www.ecdc.europa.eu/en/malaria/facts
7. NHS: “Antimalarials” – https://www.nhs.uk/conditions/malaria/treatment/
8. TheScientist: “New Malaria Vaccine Shows Most Efficacy of Any to Date: Small Trial” – https://www.the-scientist.com/news-opinion/new-malaria-vaccine-shows-most-efficacy-of-any-to-date-small-trial-68710
9. Sciencemag: “First malaria vaccine rolled out in Africa – despite limited efficacy and nagging safety concerns” – https://www.sciencemag.org/news/2019/11/first-malaria-vaccine-rolled-out-africa-despite-limited-efficacy-and-nagging-safety
10. Mayo Clinic: “Malaria” – https://www.mayoclinic.org/diseases-conditions/malaria/diagnosis-treatment/drc-20351190
11. Mayo Clinic: “A Study to Evaluate Intravenous Artesunate to Treat Severe Malaria in the United States” – https://www.mayo.edu/research/clinical-trials/cls-20502924
12. World Health Organisation: “Mekong Malaria Elimination Programme” – https://www.who.int/initiatives/mekong-malaria-elimination-programme
13. World Health Organisation: “Cambodia commits to eliminating Plasmodium falciparum malaria” – https://www.who.int/cambodia/news/detail/03-11-2020-cambodia-commits-to-eliminating-plasmodium-falciparum-malaria
Youth Medical Journal 