Malaria

This link is a short video with an overview of everything you need to know about Malaria!

What is Malaria?

Malaria is one of the world's oldest known diseases. It is a disease that infects and destroys red blood cells in the human body. Malaria has had huge consequences for most of the world for a very long time. It has prevented economic growth in many regions and has caused thousands of human deaths. To this day, Malaria still is a social, economic, and lethal problem for many countries with tropical climates, although the rates of it have decreased in other parts of the world, and is even eradicated in some regions. South Africa is one country that continues to have problems with the spread of Malaria. Infection is caused by a parasitic protozoan, Plasmodium. It has many hosts, including humans, monkeys, reptiles, and birds. These hosts are infected by a vector carrying the Plasmodium, usually a mosquito.1 Malaria usually includes symptoms that are similar to the flu, such as muscle pain, nausea, fatigue, and fever. However, Malaria is a fairly easy disease to treat in modern society, if there is access to the proper drugs.

anophelesmosquito.jpg

Pictured above is the Anopheles mosquito.

Transmission

Malaria in humans is caused by five different Plasmodium species. These include: P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.2 The two most dangerous types to humans are P. falciparum and P. vivax. Each parasite has specific restrictions in host and vector, but the five species mentioned can all infect humans. Malaria is transmitted through the bite of female Anopheles mosquitoes. Of the nearly 400 species of this mosquito, about 30 of them are vectors for the Malaria causing parasites. Female mosquitoes are the ones to be particularly careful of because they bite humans in order to get blood as a meal to help raise their eggs.3

People who live in subtropical and tropical regions of the world are at a higher risk of contracting the disease because mosquitoes have the longest lifespan in these areas. This extended lifespan results in the parasite being able to fully develop inside of the mosquito, which is not possible in places with cooler climates, such as The United States. This, combined with the fact that the African vector species have a strong tendency to bite humans, are two main reasons why Africa has about 90% of the world’s Malaria cases.3

Figure 8.6 is from WHO estimates.

Mosquitos become vectors for the disease when they bite and get the blood of an animal (or human) that is already infected. The figure below illustrates how this works. Essentially, a mosquito bites an infected person, picking up the disease. They then will move on and bite another, uninfected person. When mosquitoes bite they inject a small amount of fluid. When this occurs, they will then transfer some of the infected blood cells into the uninfected person, thus infecting the new person with the Malaria parasite.

Symptoms

Some of the major symptoms of Malaria are very similar to that of the flu. However, there are some differences, which are important in making a differential diagnosis.

Common symptoms of Malaria are1:

  • Atypical fever: Those with Malaria may or may not have a fever. If a fever is present, it may show up in various ways. It may appear as a prolonged symptom, or not at all. Fever may be continuous or intermittent, as well as with or without chills.
  • Headache: Headaches may be slight, but also can be very severe. In some cases, it is so severe that it presents as an infection of the brain. It is possible that headaches caused by Malaria may also be very similar to migraines.
  • Body or joint pain: Body and joint pain are fairly common and consistent among patients with Malaria. In cases of recurrent Malaria, it may present solely with these symptoms. In addition, body, back and joint pain may emerge before the full onset of the disease.
  • Cough: Cough is very common, especially with those infected with the P. falciparum parasite. The cough may present as mild bronchitis.
  • Overall weakness: Individuals with Malaria generally present as overall weaker than they normally are. This includes pale skin, dehydration, hypotension, and so on. In addition, patients who present in this way will generally not have a fever to go along with it.
  • Hepatosplenomegaly: This is an enlargement of the liver and/or the spleen. It may be tender, and not include a fever. This quick enlargement of the internal organs can result in sudden pain in the abdomen or chest. This symptom is usually noticeable by the second week of the disease. In addition, splenomegaly is a tell-tale sign of Malaria, but it is not required.

Treatment and Prevention

Long-lasting insecticidal nets (LLINs) 1,3 : LLINs are nets that are treated with insecticide. The World Health Organization recommends any person at risk for Malaria use these nets, as they are one of the most cost effective ways to prevent the disease. WHO also tries to provide LLINs to the people who need them for free, in order to ensure equal access for all. Essentially, the nets are put around a person’s bed to protect them from mosquito bites while they sleep, which is when most of the vector mosquitoes will bite most often. The LLINs help protect people when they are at their most vulnerable.

Antimalarial drugs 3,4 : There are several drugs that can be used, especially for travelers, to prevent Malaria. Many of these drugs suppress the blood stage of Malaria, thereby preventing infection. These drugs include Atovaquone, Doxycycline, and Mefloquine, among many others. Although these drugs are very useful in the prevention of Malaria, they do come with some fairly serious side effects. Some of these side effects include increased sensitivity to the sun, upset stomach, and even hallucinations. All of these are not ideal, especially in places where Malaria is prevalent, like Southern Africa.

Artemisinin-based combination therapies (ACTs) 5 : Once a person has gotten Malaria it is fairly easy to treat, if the person has access to the right healthcare, and can afford the healthcare needed. The best treatment for Malaria is Artemisinin-based combination therapies, especially for those infected with P. falciparum.3 ACTs have been recommended by the WHO since 2001, but the process of getting it to infected areas has been slow due to high cost and people being overall unfamiliar with ACTs and what they do.


Artemisinin is a compound that comes from the plant Artemisia annua, which can be found in China. Drugs including Artemisinin are combined with other drugs in one tablet to combat Malaria. In combination with other drugs, Artemisinin kills the Plasmodium that causes the disease. ACTs also help to reduce the number of parasites that are resistant to treatment.

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The picture above is of the Artemisia annua plant.

Malaria in South Africa

Malaria is at endemic levels in three of South Africa’s nine provinces. These provinces include Limpopo, Mpumalanga and KwaZulu-Natal. Malaria is seasonal in South Africa, being more common in the rainy months from September to May. The country saw a fairly drastic increase in the cases of Malaria in the 2016/2017 season compared to the 2015/2016 season. By March, 2017, there were approximately 9,478 cases of Malaria, with 76 deaths. This is compared to the 6,385 cases and 58 deaths in the entire 2015/2016 season. Some factors that contributed to this increase are warmer temperatures, more rainfall, and more humidity. During the summer months in Kruger National Park, there is a low to medium risk of transmission.6


In addition to having very high rates of Malaria, certain parts of South African also have high rates of drug resistant parasites. In the three regions listed as having endemic levels of Malaria, there are also many parasites that are Chloroquine resistant. This only adds more complications into treating and preventing Malaria in these reasons. This drug resistance is another reason there are so many cases, and fairly high rates of death from Malaria within South Africa. On a slightly more positive note, 90% of the infections in South Africa are due to the P. falciparum parasite, which causes one of the easiest kinds of Malaria to treat. The other ten percent of the infections are caused by the P. vivax and P. ovale species of the parasite. Overall, treatment is becoming easier to access for individuals within South Africa, and rates of death have decreased over the past few years.

Footnotes:

1.Tantular, Indah. “WHAT IS MALARIA?.” Indonesian Journal of Tropical and Infectious Disease [Online], 1.3 (2010): 122-127. Web. 7 Dec. 2018

2. N. J. White; Plasmodium knowlesi: The Fifth Human Malaria Parasite, Clinical Infectious Diseases, Volume 46, Issue 2, 15 January 2008, Pages 172-173, https://doi.org/10.1086/524889</font>

3.“Malaria Key Facts.” World Health Organization, World Health Organization, 19 Nov. 2018, www.who.int/news-room/fact-sheets/detail/malaria.

4. “Choosing a Drug to Prevent Malaria.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 25 Apr. 2018, www.cdc.gov/malaria/travelers/drugs.html.

5. Mutabingwa, T.K. “Artemisinin-Based Combination Therapies (ACTs): Best Hope for Malaria Treatment but Inaccessible to the Needy!” Acta Tropica, vol. 95, no. 3, Sept. 2005, pp. 305–315., doi:10.1016/j.actatropica.2005.06.009.

6. “Malaria in South Africa 2017: an Update.” National Institute for Communicable Diseases, May 2017, www.nicd.ac.za/wp-content/uploads/2017/05/Malaria-update.pdf.

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