How Malaria Was Eliminated from Many Developing Countries

Hannah Sheard
6 min read

While today malaria is mostly associated with Africa, up until the mid-nineteenth century this deadly disease was rampant in almost all countries, excluding countries too high in elevation or too cold for transmission. Over the past century, more than 100 countries have successfully eliminated malaria – countries in Europe, North America, the Caribbean, and parts of Asia and South and Central America. Although sub- Saharan Africa accounts for the large majority of malaria cases today, many countries in the developing world have successfully eliminated malaria.

Malaria is a life-threatening disease caused by a parasite in the genus Plasmodium. The malaria vector, or the vehicle that transmits the disease, is the female Anopheles mosquitoes.

Photo: Anopheles mosquito

When discussing malaria control, or the reduction of cases of malaria, there are two important terms that need to be defined – elimination and eradication. Elimination refers to an end in the local transmission of malaria, while eradication means a permanent end to malaria. Local transmission refers to malaria that is contracted in the area. For example, many countries have eliminated malaria, but still have a few confirmed cases each year due to travelers who contracted malaria in other countries. Malaria eradication will require malaria to be completely gone from every country, resulting in zero transmission across the world.

The World Health Organization (WHO) declares that a country is malaria-free once there have been zero local transmission cases over a period of three years. To be certified as malaria-free, countries must choose to undergo the WHOs certification process; therefore, while over 100 countries have eliminated malaria, only 36 countries have been certified as malaria-free by the WHO.

Many developed countries have successfully eliminated malaria, some since the 1950s. These countries, such as the United States and certain European countries, began their elimination efforts during the first half of the nineteenth century, shortly after the malaria vector was discovered in the 1890s. The most common form of disease control used was vector control – the idea that by eliminating the vector that spreads a disease the disease will also be eliminated. Vector control included spraying homes with the insecticide DDT and destroying the natural habitats of the Anopheles mosquitoes. While DDT is no longer allowed to be used in some countries, other insecticides have proven useful for vector control.

Upon seeing these countries’ initial successes in malaria elimination, the WHO developed the Global Malaria Eradication Programme in 1955. This program focused largely on two methods to accomplish its goal: the use of chloroquine (an antimalarial drug) as prevention and treatment and the use of DDT as insecticide. Although this program helped 15 countries eliminate malaria, it was abolished nine years later because it was difficult to sustain.

Over the next several decades, malaria incidence increased across the world. It wasn’t until the 1990s when several new efforts to reduce malaria were introduced. These efforts include the WHO’s Global Malaria Control Strategy and Roll Back Malaria initiative. During this time, more money was invested into malaria research, leading to the development of long-lasting insecticide-treated nets (LLIN), rapid diagnostic tests (RDT), and artemisinin-based combination therapies (ACTs).

Long-lasting insecticide-treated nets are insecticide-treated nets (ITN) that last up to three years. Both nets are forms of vector control, and their efficacy was demonstrated in Tanzania, China, and Vietnam. To use, these nets are draped over beds to keep mosquitoes away when a person is sleeping. Nets have been seen to reduce the malaria mortality rate by 20%, and are an important tool in the fight to control malaria.

Artemisinin-based combination therapies are currently the recommended treatment for malaria. These treatments mix 2 different drugs together to reduce the number of malaria parasites in the bloodstream. Artemisinin-based combination therapies have been essential in reducing malaria cases in recent years.

The invention of rapid diagnostic tests allowed for quick and accurate malaria detection. This was (and is) particularly important in areas where diagnosis had previously been impossible or unreliable.

Photo: Insecticide-treated net

One form of malaria control that’s efficacy has been questioned is mass drug administration (MDA). Mass drug administration is when antimalarial drugs are given to all members of a given population. Countries in South America, Africa, and more have used this method, but it’s effectiveness was called into question by reports of increased numbers of resistant Plasodium. Currently, forms of mass drug administration are recommended for areas that are low-risk and are nearing malaria elimination.

In most countries, vector control and an effective healthcare system are some of the most fruitful tools for eliminating malaria. By looking at some of the countries that have most recently eliminated malaria, we can see some effective measures that developing countries have taken to get rid of this disease.

Last year, Argentina was officially declared-malaria free. To accomplish this, they trained health care workers to spray homes with insecticide (vector control) and ensured quick and effective diagnosis and treatment of malaria cases. Argentina also collaborated with Bolivia to secure and spray down the border areas, as well as to conduct malaria testing. This cross-border collaboration was key in eliminating malaria in Argentina and has proven to be essential for malaria elimination in other countries as well.

Algeria also became malaria-free in 2019. Just as Argentina provided free malaria diagnosis and treatment to people within its borders, this method was effective in Algeria as well. In addition to free treatment, Algeria had a well trained and equipped healthcare team that had a rapid response to malaria cases.

Both Argentina and Algeria have been making, deliberate, conscious efforts to eliminate malaria since the late 1900s. In many developing countries, years of work are put into malaria control before the results can truly be seen. In Uzbekistan, for example, malaria control began in 1921. Uzbekistan increased healthcare access, drained swamps, sprayed insecticide, and treated mosquito larvae breeding grounds with chemicals. These efforts were successful, and malaria was thought to be eliminated in 1961. However, malaria quickly resurfaced as cross-border transmission continually occurred. Since then, Uzbekistan undertook sweeping measures to get rid of malaria once and for all. Access to healthcare (particularly at the borders) increased, and insecticide spraying resumed. After eliminating malaria in 2010, Uzbekistan officially sought and achieved malaria-free status by the WHO in 2018.

Why have only some countries eliminated malaria? One reason is the health system infrastructure. By looking at Argentina and Algeria, we can see that eliminating malaria requires the ability to immediately treat cases of malaria in order to stop the spread. Immediate access to anti-malaria drugs is not always accessible in all countries, particularly in poor countries. Another reason is that many countries that still have malaria, including many of the countries in Africa, have an ecosystem that is highly suitable for mosquitoes. Their warm climate means that malaria can be transmitted year-round, not just seasonally during the warmer months. While destroying mosquito habitats was helpful in eliminating malaria in certain countries, it will be much more difficult to destroy mosquito breeding grounds in Africa.

Additionally, resistance is a key problem that must be faced. As the Plasmodium parasites develop resistance to antimalarial drugs, new treatments must be developed to combat this issue. The same goes for the Anopheles mosquitoes – as they develop resistances to certain insecticides, new insecticides must be created and used.

Will malaria ever be fully eradicated? Scientists differ in their answers to this question. General consensus is no – at least, not at the moment. Many technological advances will be necessary before eradication is possible.

References:

Anuraag Bukkuri. “The history of malaria in the United States: how it spread, how it was treated, and public responses.” MOJ Anatomy & Physiology 2(3) (2016).

Centers for Disease Control and Prevention. “Insecticide-Treated Bed Nets.” (2019).

Francis Cox. “History of the discovery of the malaria parasites and their vectors.” Parasites & Vectors 3 (2010).

Janie Zuber and Shannon Takala-Harrison. “Multidrug-resistant malaria and the impact of mass drug administration.” Infection and Drug Resistance 11:299–306 (2018).

Jasminka Talapko et al. “Malaria: The Past and the Present.” Microorganisms 7(6):179 (Jun 2019).

Thomas Eisele. “Mass drug administration can be a valuable addition to the malaria elimination toolbox.” Malaria Journal 18 (2019).

World Health Organization. “Algeria and Argentina certified malaria-free by WHO.”(2019).

World Health Organization. “Eliminating Malaria.” (2016).

World Health Organization. “Q&A on artemisinin resistance.” (2019).

World Health Organization. “Rapid diagnostic tests.” (2019).

World Health Organization. “WHO certifies that Uzbekistan has eliminated malaria.” (2018).

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