Malaria: Difficulties Contributing to Eradication Efforts within Central Africa

By Claire Heetderks • Health Humanities, Cycle 12, Fall 2023
 

 

Introduction

Malaria is a disease spread by mosquitoes that kills around six hundred and fifty thousand people each year. Four countries in Africa, Nigeria, the Democratic Republic of Congo, Tanzania, and Niger, account for over half of malaria deaths worldwide (World Health Organization, 2022). While there are still some malaria cases within the United States (US), it was considered eradicated and no longer a public health threat in 1949. Other countries, including those within central Africa, have struggled to eliminate the disease, causing public health officials to ask why. As governments and global aid organizations create new public health policies to implement within these countries, they must consider the factors that influence malaria, including environmental and social impacts. Specifically, malaria spread within outbreak countries is heavily influenced by climate, socioeconomic status, and migration.

General Transmission

Malaria spreads through female mosquitoes, specifically, Anopheles mosquitoes, which are the primary vector of the parasite plasmodium and, in turn, malaria. When female mosquitoes go to take blood, they infect the human or animal with the plasmodium, spreading the parasites into the blood, where they multiply within the liver and red blood cells (Centers for Disease Control, 2022). If another mosquito goes to drink the blood of the now-infected human, it becomes infected with the plasmodium parasite, and the cycle repeats itself, causing outbreaks. Due to the long life cycle of the parasite within humans, malaria can be mild or severe, with symptoms ranging from a common virus to flu-like symptoms, coma, and death (Centers for Disease Control, 2022).

Historical US Prevention Methods

Analyzing the advantages, disadvantages, and consequences of the tactics used by the United States to eradicate the disease in the 1940s is essential to understanding the state of malaria eradication today. The United States’ eradication of malaria began in 1942 when the Centers for Disease Control’s (CDC) predecessor, the Office of Malaria Control, was established to limit the impact of malaria and other vector-borne diseases within military training bases during World War II. Due to the critical importance of World War II, the US government willingly funded the Office of Malaria Control to ensure the health of troops and medical staff and create new antimalarial drugs that would allow the US army to succeed. First used during World War II, antimalarial drugs were given to soldiers who traveled to areas with high case rates or known outbreaks of malaria.

Along with educating and preserving the health of the military, the Office of Malaria Control also created the National Malaria Eradication Program to ensure the health of the civilians. This program, first carried out in the southern US in the 1940s, focused on environmental management consisting of spraying homes with dichlorodiphenyltrichloroethane (DDT), a highly toxic insecticide, as well as water drainage, removal of mosquito breeding sites, and creation of safer homes through the implantation of screened windows and closed roof eaves (Centers for Disease Control, 2020).

The US public was also educated on the threats of malaria with a famous Walt Disney short film. The film portrays the seven dwarves filling in puddles, sleeping with bed nets, and spraying Paris Green, a green insecticide, on their homes and lakes (Walt Disney, 1943). The film was also distributed within Latin American countries as the US wanted to educate and ensure the health of allied soldiers. Countries currently use much safer insecticides than DDT and Paris Green due to their now-known extreme negative consequences on soil, biodiversity, and human health.

The use of powerful insecticides, housing reconstructions, public awareness campaigns, and the persistence of the United States government and their deep funding allowed the United States to fully eradicate malaria within the country by the end of the 1940s. While these measures worked within the US in the early 1900s, they are challenging to implement in African countries today as most mosquitoes have adapted to be resistant to insecticides, and countries currently lack the funding to implement changes in housing. However, the tactics used by the US can be learned from. While African countries work to develop new preventative measures and policies, it is still essential to implement education on malaria and distribute current preventive measures as they still limit case numbers and the severity of infection.

Current Preventative Methods

Malaria is transmitted via mosquito bites; therefore, current preventative measures focus on limiting mosquito populations and controlling their interactions with human populations. Current preventive measures include insecticides, wearing long-sleeved clothing, using bed nets, and antimalarial medications. Insecticides sprayed on houses work by targeting the insect’s nervous system and killing the insect within minutes or hours of direct contact or ingesting the chemical. Bed nets offer another layer of protection within homes as the nets prevent mosquitoes from biting when individuals are sleeping. Lastly, antimalarial medications work to kill the malaria parasite during its development stages and prevent the symptoms of the disease. Currently, these preventative measures are widely considered the best defense against malaria and must continue to be distributed within high-transmission regions through the help of aid organizations.

Promising New Preventative Methods

To surpass the limitations of current preventative measures, scientists have more recently sought to develop vaccines and new technologies as a long-term public health solution. Current limitations of preventive measures include the fact that bed nets are becoming less effective as anopheles mosquitoes are becoming resistant to the insecticides sprayed on the nets. In response to these evolving limitations, Dr. Ochomo and other researchers have been experimenting with a new technology in Kenya, spatial repellents (Ochomo et al., 2022). Spatial repellents are plastic films placed on walls that release chemicals into the air over time and interfere with the mosquitoes’ ability to find a host, preventing them from entering homes and biting (Ochomo et al., 2022). Along with the technology, researchers have developed new insecticides and chemicals to use within the spacial repellents that mosquitoes have not encountered or become resistant to. These new chemicals can also be distributed to be used on bed nets to ensure the most current effective prevention against mosquitoes.

Along with new preventative measures such as spatial repellents, malaria vaccines are also being researched and produced; however, no malaria vaccine has reached the threshold 50% efficacy rate. Efficacy varies with each disease type and is measured by how many people who get vaccinated develop the outcome of interest compared with how many who get the placebo and develop the same result. High efficacy rates are difficult to achieve for malaria as the parasites have a complex and adaptable life cycle; the parasites can produce thousands of different antigens, making it difficult for scientists to understand and target the disease (World Health Organization, 2022).

Currently, there are twelve malaria vaccine approaches, the most common being blood-stage vaccines, whole parasite vaccines, and mosquito-stage vaccines. Blood-stage vaccines target the disease-causing stage of the plasmodium parasite life cycle, while whole parasite vaccines block the establishment of parasites within the host (Hill, 2011). Lastly, mosquito-stage vaccines target antigens from the plasmodium in the liver stages (Hill, 2011). The current most promising malaria vaccine is RTS, S/AS01, a four-dose vaccine combining these different approaches. It fully acts against Plasmodium falciparum, the deadliest malaria parasite (Laurens et al., 2020). Clinical trials have shown significant reduction against malaria, especially severe malaria in children. Over one million children in Ghana, Kenya, and Malawi have been vaccinated. They benefit from the added protection provided by the vaccine as part of a pilot program (Laurens et al., 2020). While the vaccine does not have a 50% efficacy rate, this is the first malaria vaccine recommended for use by the World Health Organization (WHO) and the European Medicines Agency, two world-renowned public health agencies. The creation of this vaccine for children shows a step in the right direction toward future preventative methods for malaria.

Climate Change

Climate influences a country’s ability to stop the spread of malaria as mosquitoes thrive in warm, wet environments, and climate change has increased the scope of their possible environment. Decreasing yearly rainfall attributed to climate change allows mosquitoes to breed longer as the rainfall no longer wipes out the stagnant water in which mosquitoes breed. This decrease in moisture caused by climate change has also caused an increase in urbanization within Africa as subsistence agriculture is no longer dependable due to droughts. Hence, people migrate to urban areas for better economic opportunities (Pecor et al., 2022). As communities migrate to urban areas, population density increases, leading to more accessible proximities for anopheles mosquitoes to infect individuals and pass malaria on to one another.

Along with decreasing rainfall, hotter temperatures due to climate change also influence the spread of malaria. Specifically within central Africa, areas of high altitude are now experiencing malaria outbreaks as temperature increase has allowed mosquitoes to breed in areas that were initially too cold for mosquitoes to survive. A recent study found that the temperature at which anopheles mosquitoes can transmit disease has increased, allowing the months of transmission and regions of transmission within Africa to widen in scope (Vilenna et al., 2020). This development now enables anopheles mosquitoes to breed almost all months of the year and in urban areas where they initially could not survive.

The increased difficulty of eradicating malaria due to climate change is apparent through the introduction of a new type of anopheles mosquito within Djibouti known as Anopheles stephensi (Pecor et al., 2022). First reported in Djoubti in 2012, Anopheles stephensi arrived from Asia and is resistant to all insecticides. It has also biologically adapted to live in urban areas and survive in dry seasons, allowing the species a much vaster range of possible infections. As communities migrate to urban areas for better economic opportunities, individuals are at higher risk of getting much sicker from malaria as they don’t have acquired immunity from previous exposure. One research study has concluded that the percentage of Anopheles stephensi has begun to increase in regions outside Djouboti, where the spread began (Pecor et al., 2022). For example, Sudan, a country with previously low malaria rates, experienced a malaria epidemic in 2012 due to Anopheles stephensi (Abubakr et al., 2022). As yearly temperature and rainfall continue to vary due to climate change, the environment of mosquitoes will continue to adapt and evolve, allowing malaria outbreaks to continue without proper intervention.

Socioeconomic Status

Socioeconomic status influences a country’s ability to eradicate malaria, as many poverty-stricken countries and regions are more prone to mosquitoes and are not given the resources or financial help needed to prevent infection. Countries that lack resources such as bed nets, insecticides, and rapid treatment of antibiotics are more prone to more significant outbreaks that spread faster (Idris et al., 2022). Even countries with resources are influenced by corruption and bribery within the government and health systems, as bribes are sometimes used to get care faster. Poorer patients are more reliant on public services and, therefore, more vulnerable to bribery (Hsiao et al., 2019). Patients are confronted with having to pay the bribe or delaying seeking care until they are much sicker. Corruption also affects communities because distrust of the healthcare system can influence whether individuals seek treatment.

Within a case study reviewing the malaria outbreak in South Sudan in 2018, the authors assessed clinic data collected from participants who had received a recurrent malaria diagnosis and had visited one of the three primary healthcare centers. This research provides evidence that when patients don’t complete their prescribed treatment regimen, the severity of malaria recurrence drastically increases. The authors concluded that factors such as marital status, employment status, use of preventative measures, and nutrition status all played a role in how willing participants were to take the antibiotics (Idris et al., 2022). For example, within this case study, the authors concluded that some individuals were not using their bed nets properly as a preventative technique and were instead using the nets for fishing. When interviewed, the individuals cited that they knew of the consequences but were considering more pressing matters, such as feeding their families.

Socioeconomic status can also influence how malaria is spread due to the relationship between poverty and housing. The risk of malaria infection increases with structures that contain cracks or openings, allowing for contact between individuals and mosquitoes. These homes are often found in poverty-stricken areas as these individuals cannot afford other housing. These homes are also usually located near ideal mosquito breeding grounds, as these areas are often the least expensive and desirable for community development (Idris et al., 2022). Given this research, when considering what best resources and techniques should be used for malaria eradication, socioeconomic status differences must be considered as to ensure equitable protection from the disease.

Migration

Migration can influence the eradication of malaria as migrants can reintroduce malaria to areas of low transmission, and inadequate education on malaria can cause a lack of surveillance and accountability. Some individuals may have malaria and be unaware, causing outbreaks in the new areas they migrate to. Migrants traveling from low to high-transmission regions are more likely to acquire severe malaria as they have not built up acquired immunity (Lin et al., 2022). In comparison, migrants who travel to low-transmission areas or communities with high immunity due to a past outbreak may reintroduce malaria. Farmers commonly spread malaria across borders as some will spend multiple days within a farming site before traveling back to be with their families when not working. This prolonged exposure spreads malaria to new populations or reintroduces malaria back into a low-transmission area.

In one case study on migration patterns, researchers tested hundreds of workers within the work sites via PCR tests. They concluded that a majority had contracted malaria through their border work. Through the local public health agency, workers took antibiotics and received bed nets and an educational lesson on the spread of malaria. The camp where workers stayed was treated with insecticides over the next several days. The local government and CDC followed up with patients days or weeks later to ensure they were keeping up with their treatment and understood how the disease could spread through their community (Lin et al., 2022). This case study, along with other research, suggests that surveillance of migrants and malaria patients remains successful in helping prevent the spread of malaria. Given the positive impact of the preventative measures used within this case study, countries should work to distribute the resources needed to prevent malaria and implement effective surveillance and response systems to help prevent the spread of malaria caused by migration. While many researchers know this task is daunting, they believe it is feasible mainly as malaria migrates into urban areas and areas of higher socioeconomic standing, forcing private corporations and aid organizations to take the problem more seriously.

Health Policy

Malaria policy must be executed at the local level as local communities are more aware of what resources would benefit their health and communities’ well-being (Lin et al., 2022). The World Health Organization wants more funding for malaria prevention education, resources, and vaccine research (World Health Organization, 2022). The WHO made ample progress toward reaching these policy milestones until COVID-19 set them off course, as resources and medical staff were incredibly limited, and funding was redirected (World Health Organization, 2022). With public health coming to the forefront of attention due to COVID-19, organizations are reevaluating their goals and ensuring that countries, such as those in central Africa drastically impacted by COVID-19, are set on the right path.

An example of effective health policy change is the WHO’s response to the Ebola epidemic in West Africa in 2018. The WHO created a new policy system beginning with the implementation of resources, education, and research at the local level. The WHO also ensured corruption and bribery were considered within their new policy by increasing transparency and getting more local participation within government and healthcare. Research has shown that this policy has been highly effective and allowed for more efficient care and prevention. While this is a step in the right direction, countries that contribute to the funding of the World Health Organization must hold the WHO accountable and ensure progressive policy is implemented over the next several years.

Conclusion

The response to malaria from central African countries has been different from that of the US in the 1940s due to various factors, including the evolution of mosquitoes, increasing climate change, the economy and healthcare corruption of African countries, as well as patterns of migration. Health policy should focus on implementing new preventative measures such as newly developed insecticides and spatial repellents, funding and implementing malaria vaccines, and educating the public on malaria. Policy should also focus on longer-term goals of creating better housing infrastructure and malaria surveillance, which would help prevent future outbreaks. Given the most recent research on malaria, when policy is implemented, local culture, opinions, and reasoning must be considered to ensure the most effective prevention. With these new implementations, lives can be saved, and eradicating malaria within central Africa and other regions with high transmission rates can become a realistic goal.