Tropical Diseases in Africa – Malaria

by Shravya Murali – Art in Tanzania internship

As a significant health problem in several tropical regions of the world, malaria costs almost 435,000 lives annually. A substantial fraction of these deaths occurs in Africa. The proportion of cases and deaths In Tanzania alone constitutes to 3% of those globally. Over the past few years, the number of malaria cases have been on the rise, with a staggering increase by 3.5 million from 2016 to 2017 as reported by the WHO.

How does malaria spread?

Malaria in humans is caused by four kinds of parasites from the Plasmodium genus – Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. A fifth species Plasmodium knowlesi, is a zoonotic species infecting animals. Of the five species, P.falciparum results in the most severe form of malaria and is responsible for the majority of malaria-related deaths, especially among children below the age of five.

Malaria is transmitted to humans through the bite of a female Anopheles mosquito that is infected by one of the malaria-causing parasites. The Anopheles mosquito can also spread the parasite from a human to another human when it feeds on an infected human’s blood meal, and later goes to bite another human.

Human-to-human transmission can also occur through blood transfusion, organ transplant, or sharing needles containing contaminated blood as the malaria parasite can be found on red blood cells. Malaria can also be transmitted from a pregnant mother to her child before or during delivery, which is also known as congenital malaria.

However, malaria is not contagious and cannot be transmitted through casual contact (i.e., by sitting next to someone infected) or sexual contact.

What are the effects of the disease?

Those infected with malaria often experience flu like illnesses and fever. Symptoms often include headache, fatigue, chills, muscle soreness, nausea, vomiting, and diarrhoea. As malaria can cause a loss of red blood cells it may lead to anemia, and jaundice, which is the yellow colouring of skin and eyes. If left untreated malaria becomes life-threatening as it can cause kidney failure, mental confusion, seizures, coma, and death. Usually, these symptoms occur about 10 days after a malaria infection.

Malaria caused by P.vivax and P.ovale may occur again and the parasites may reside in the liver for up to around four years after an individual has been bitten by an Anopheles mosquito. These dormant parasites may become active later and invade the individual’s red blood cells, causing another malarial infection.

How is malaria treated?

If a patient is suspected to be infected with malaria, a drop of his/her blood is often observed under a microscope to detect the malaria parasite. Treatments for malaria vary based on the severity of malaria, clinical status of the patient, the Plasmodium species causing the infection, and prior use of anti-malarial drugs.

In Mainland Tanzania, artemether lumefantrine, a drug that can be orally consumed, is used for uncomplicated malaria. In Zanzibar, however, artesunate and amodiaquine are used. For severe malaria, artesunate and quinine are injected in patients in both Mainland Tanzania and Zanzibar. Quinine is another drug that is only used when other drugs are ineffective, as quinine is known to have more side effects than the others. However, quinine is used to treat malaria in the first trimester of pregnancy as it is not known to have significant effects on the child at therapeutic doses.

What could be done to prevent the disease?

To prevent malaria, one could consume anti-malarial drugs (i.e., atovaquone, chloroquine, doxycycline). While it is possible to provide infants and children some of these drugs, not all drugs are suitable for children and doses are based on the weight of the child.

Apart from anti-malarial drugs, one should also prevent mosquito bites (specifically at night), which could be done by sleeping under insecticide-treated bed nets, wearing fully covered / long-sleeved clothing at night, and carrying an insect repellent.

With the increase in the number of malaria cases over the years, it is crucial that members of the public and healthcare professionals cooperate in fight against the disease. While the research for vaccination against malaria is ongoing, it is also essential for everyone to play a part by taking precautions to avoid malaria.

References:

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2. Centers for Disease Control and Prevention. (2021, January 26). CDC – Malaria – About Malaria – FAQs. Centers for Disease Control and Prevention. https://www.cdc.gov/malaria/about/faqs.html.

3. Mutabazi, T. (2021, June 6). Assessment of the accuracy of malaria microscopy in private

health facilities in Entebbe Municipality, Uganda: a cross-sectional study. Malaria Journal. https://malariajournal.biomedcentral.com/articles/10.1186/s12936-021-03787-y

4. Ryan, S. J. (2020, May 1). Shifting transmission risk for malaria in Africa with climate

change: a framework for planning and intervention. Malaria Journal. https://malariajournal.biomedcentral.com/articles/10.1186/s12936-020-03224-6

5. Tanzania. Severe Malaria Observatory. (2007, January 17). https://www.severemalaria.org/countries/tanzania.

6. Thomas, D. L. (2020, March 13). Triple therapies effective and safe in malaria. News. https://www.news-medical.net/news/20200312/Triple-therapies-effective-and-safe-in-malaria.aspx.