Why Haven’t We Eradicated Malaria?
Let’s talk about the number one killer in human history.
by Valeria Lau
Malaria has existed for as long as we have. This mosquito-borne disease is estimated to have killed more humans than all plagues and wars combined. Now a foreign idea for the Western world, this relentless killer has become one of the most unshakeable drivers of global inequality. Malaria is currently responsible for an estimated 450,000 annual deaths. In 2016 alone, the WHO recorded 216 million cases of the disease, the vast majority of these deaths being of women and children in Sub-Saharan Africa, which is one of the most economically depressed regions in the world.
The ramifications of a malaria epidemic are so severe, that its death toll is likely to be much higher than what is currently reported. Malaria is an immunosuppressive disease. This means that, while those who are exposed to it might build a certain immunity to some strains of malaria, they become more vulnerable to other types of infections, such as tuberculosis and influenza. This disease can also cause complications in pregnancy, causing countless miscarriages and maternal deaths.
Malaria’s unwavering grip on some of the world’s most disadvantaged nations affects their development on many levels. Poverty, political instability, and a lack of education are aggravated in malarious countries. However, this disease has not always been the burden of low-income, equatorial regions. In fact, only one century ago, malaria was found all over the globe. Nations such as the United States and the United Kingdom are not commonly associated with this seemingly tropical disease, but they did not escape malaria’s erosion of their respective demographics.
Most of the world suffered from this disease without much understanding of its modes of transmission, but antimalarial medicines have been known for centuries. For instance, the Quechua people of Peru were using quinine, a natural medication that comes from tree bark, since before the 15th century. The transmission of malaria by mosquitoes was discovered in 1897 by a British officer in India. Since then, great strides have been made in the development of antimalarial drugs and prevention methods. Nonetheless, malaria remains one of the leading causes of death worldwide in 2018. To understand how this situation can be changed, it is essential to understand the scope of the obstacles to eradicating this disease.
What exactly is malaria anyway? We hear of its devastating effects on humanity, but the disease in itself is still widely misunderstood across the world. There are thousands of mosquito species in the world, but there is only one genus that is responsible for being the vector of malaria: the Anopheles. Anopheles — derived from the Greek term for “useless” — can carry parasites of the Plasmodium genus, which it spreads into the human bloodstream while feeding.
Malaria is not caused by any single parasite; there are five different strains of Plasmodium that cause the disease in humans, all with different manifestations and degrees of severity. This further complicates the impact of malaria, as any immunity acquired for one strain of the parasite is ineffective for the rest of them. Once this parasite has entered the human body, it burrows itself into the liver, hiding in there for many days. It then changes forms and begins multiplying rapidly. The most severe strains of malaria parasites can multiply abundantly enough to clog the capillaries of the brain, the kidney, and the liver, resulting in organ failure. As the parasite evolves within the body and starts to affect blood cells, the infected individual can experience chills, fever, headaches, joint pain, and even convulsions, vomiting, coma, and death.
Throughout the journey of the Plasmodium parasite from the body of the mosquito to the complete infection of the human body, the microorganism changes its form seven times. This is one of the reasons why antimalarial drugs have a low efficiency rate — each of the forms of the parasite has different strengths, weaknesses, and characteristics. It is almost impossible to generate a drug that is effective against Plasmodium in all of its different forms and strains.
Most importantly, the constant evolution of the parasite is resulting in an increasing resistance to antimalarial drugs. It doesn’t take long after new medical advancements arise for the malaria parasites to catch up. In particular, some of the species of Anopheles that plague Africa have evolved to prefer human blood over the blood of cattle, which drastically increases the odds of infection. Africa’s burden is further increased by the availability of mosquito breeding grounds and the tropical temperatures which accelerate the growth of the Plasmodium parasite.
This can make malaria sound quite terrifying, but the reality is that the large majority of malaria cases come and go, much like the way that the cold and flu comes and goes in Western nations. Many people that are infected with the parasite do not even develop symptoms. Some people in Sub-Saharan Africa experience over 40 different episodes of malaria during their lifetime. This is the root of one of the most significant and overlooked obstacles to curing this disease; it is extremely normalized in malarious communities.
The American investigative journalist Sonia Shah has dedicated several years of research to the social barriers preventing the eradication of malaria. In her book The Fever, she describes how a small community in Malawi was indifferent to the availability of antimalarial bed nets as they were perceived as an ineffective, cumbersome precaution. In such regions, traditional beliefs attribute the transmission of malaria to mosquitoes, but also to many other factors such as bad weather, dirty water, proximity to cattle, and more. Shah explains that, while these people of Malawi know that mosquitoes transmit malaria, these only represent a fraction of the possible threats of contagion in their eyes. Therefore, going out of their way to prevent this ubiquitous disease with inconvenient nets or costly drugs seems, to many, like an absurd reaction to a normal part of life.
The rate of mortality per episode of malaria is, evidently, quite low. However, there is such a large number of infections in the world that the total number of deaths remains extremely elevated. This difference in perspectives between malaria endemic countries and rich, Western nations is responsible for the inefficiency of many humanitarian efforts. Many NGOs focus their efforts on delivering drugs and insecticide-treated bed nets to malarious communities without much regard for the way these will be received by the people most familiar with the disease.
Malaria control is dependent on important economic investments. Considering the enormous toll of malaria on much of the developing world, it is not surprising that this disease has been at the centre of several humanitarian efforts to reduce disease and mortality rates. Many philanthropic initiatives have made the eradication of malaria a priority, as has the Bill & Melinda Gates Foundation, by investing upwards of $250 million into the research and development of vaccines and the elimination of the disease.
Malaria has garnered so much international public attention that, with aggressive eradication efforts, the global incidence of the disease was reduced by 41% between the year 2000 and 2015. However, as the interest of the international community has waned in the past years, funding for malaria control has decreased. Currently, funding is limited to below $2 per at-risk person in high-burden countries. The high cost is one of the main challenges of malaria eradication. Investment projects in malarious regions are rare, as the disease is a powerful threat to any economic viability.
Those who are most afflicted generally live in rudimentary housing where window screens are almost useless, since mosquitoes can infiltrate easily. The lack of electricity means less time spent indoors, and land-based work, such as agriculture and mining, leaves people exposed to mosquitoes for a majority of their waking lives. There is often a lack of land drainage in malarious regions that allows the Anopheles mosquito to thrive. The Anopheles’ ideal spawning habitat is still water, where the mosquito lays its eggs. Unfortunately, humans are very prone to creating these habitats. Agriculture, deforestation, the deviation of bodies of water, and the creation of dams are all human activities that favour the reproduction of the Anopheles mosquito. Climate change in itself causes environmental irregularities that allow for a constant spread and renewal of mosquito populations.
The list of complications can go on. Difficult access to remote malarious communities, growing resistance to insecticides, the rapid spread of diseases in conflict zones, and more stand in the way of those fighting towards eradication. However, malaria has been defeated in much of the world, and in stunning proportions. Most of the ‘developed’ world drove malaria away by improving its living conditions — modern drainage systems, accessible healthcare, quality housing, and access to electricity are only some of the ways richer nations became less vulnerable to malaria. Spraying with DDT, a powerful insecticide, further eliminated the vector of the disease in North America and Europe before this harmful chemical was widely replaced by less toxic alternatives.
These advancements, however, are not exclusive to rich Western nations. Many low-income countries have won their fight against malaria in the last decade, with Sri Lanka as the latest nation to be certified malaria-free by the World Health Organization. Eradication strategies must be highly individualized to the particularities of the terrain, demographic, and economy of each region. Nonetheless, paying attention to the case of Sri Lanka can provide valuable insight into a successful approach to local eradications of malaria.
Despite experiencing the toll of internal conflict and a malaria burden that resulted in more deaths than births for decades, Sri Lanka faced the disease with a particularly powerful resolve. The government’s malaria programme tackled the issue from many angles, DDT spraying being one of the main components of the plan. Despite low acceptance rates due to the smell and colour of the insecticide, spraying DDT indoors eventually became one of Sri Lanka’s main weapons against the malaria vector.
Another main component of the programme was the careful monitoring of national malaria trends with heavy, decentralized surveillance of reported cases. This information allowed the government to predict where major epidemics would arise, and where their efforts would be most needed. Sri Lanka also focused on fast and efficient diagnostics: everyone who checked into a clinic would be screened for malaria, no matter the cause of their visit. One of the most remarkable initiatives of the nation’s programme was the putting in place of mobile clinics that delivered fast and efficient treatment to remote areas.
Scientific advances have created new hope for the eradication of malaria. Numerous experts are developing genetically modified species of mosquitoes that target the vector in one of two ways: causing sterile mosquito offspring, or removing its ability to carry the Plasmodium parasites. Using gene drive CRISPR technology to ensure that the modified gene will be dominant is a fast and sustainable way to wipe out the Anopheles carriers of malaria, or malaria itself once and for all. The efficiency of genetically modified mosquitoes for disease control has already been put to the test in trials in Brazil; one targeted attempt to reduce instances of dengue fever actually resulted in a 91% decrease in new infections within the affected community.
This genetic technology, when combined with aggressive eradication strategies, such as those undertaken by Sri Lanka, offers a new hope in overcoming a very deadly chapter of humanity. However, these technologies are only a few years old and have yet to be developed in a large enough scale. A vaccine is currently being developed with the support of the WHO and organizations such as the Bill & Melinda Gates Foundation, alongside countless scientists around the world. Furthermore, the use of drones for the distribution of insecticides over mosquito breeding grounds is being explored, expanding the reach of this technology.
For all of this to succeed, an increase in funding and a long-term commitment to the eradication of malaria are essential. Scientific advances are not enough to result in lasting change — social change is needed. Education and awareness-raising within malarious communities will allow those most affected by the disease to protect themselves better. On the flip side, the international community needs success stories, visibility of anti-malaria initiatives and to place political pressure upon world leaders for support of the fight against the disease.