Chris Lourens (MT)
What did King Tutankhamun, George Byron, Oliver Cromwell, Vasco da Gama, David Livingstone, Louis III of Naples, Alexander the Great, Dante and King Otto II all have in common? They all died of malaria. That leaves us with a history of over 3300 years and we are still fighting it.
Malaria is a mosquito-borne infectious disease of humans and other animals caused by parasites of the genus Plasmodium. Commonly, the disease is transmitted by a bite from a pesky infected female Anopheles mosquito, which introduces the parasite from its saliva into a person’s circulatory system. In the blood, the parasites travel to the liver to mature and reproduce. Malaria causes symptoms that typically include fever and headache, which in severe cases can progress to coma or death.
The disease is widespread in tropical and subtropical regions in a broad band around the equator, including much of Sub-Saharan Africa, Asia, and the Americas. But it is also easily transported by tourists or visitors from malarial areas to any part of the world. The World Health Organization estimates that in 2010, there were 219 million documented cases of malaria. That year, the disease killed between 660,000 and 1.2 million people, many of whom were children in Africa.
The signs and symptoms of malaria typically begin 8–25 days following infection; however, symptoms may occur later in those who have taken antimalarial medications as prevention. Initial manifestations of the disease—common to all malaria species—are similar to flu-like symptoms, and can resemble other conditions such as septicemia, gastroenteritis, and viral diseases. The presentation may include headache, fever, shivering, joint pain, vomiting, hemolytic anemia, jaundice, hemoglobin in the urine, retinal damage, and convulsions.
Infection with P. falciparum may result in cerebral malaria, a form of severe malaria that involves encephalopathy. It is associated with retinal whitening, which may be a useful clinical sign in distinguishing malaria from other causes of fever. Splenomegaly, severe headache, hepatomegaly (enlarged liver), hypoglycemia, and hemoglobinuria with renal failure may occur.
In humans, malaria is caused by P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi. Among those infected, P. falciparum is the most common species identified. Malaria in pregnant women is an important cause of stillbirths, infant mortality and low birth weight, particularly in P. falciparum infection, but also with P. vivax.
Uncomplicated malaria may be treated with oral medications. The most effective treatment for P. falciparum infection is the use of artemisinins in combination with other antimalarials (known as artemisinin-combination therapy, or ACT), which decreases resistance to any single drug component. These additional antimalarials include: amodiaquine, lumefantrine, Mefloquine or sulfadoxine/pyrimethamine. Another recommended combination is dihydroartemisinin and piperaquine. ACT is about 90% effective when used to treat uncomplicated malaria. When properly treated, people with malaria can usually expect a complete recovery. However, severe malaria can progress extremely rapidly and cause death within hours or days.
So why are we still fighting these little pests? P. falciparum has the amazing ability to mutate and build up a resistance to all of our wonderful drug discoveries. Drug resistance poses a growing problem in 21st century malaria treatment. Resistance is now common against all classes of antimalarial drugs and even the artemisinins are now showing signs of reduced effectiveness in Asia. Resistance to antimalarial drugs spread from Asia to Africa and South America.
So, how can we prevent getting malaria? Don’t get bit. Use skin lotions or sprays and mosquito repellants. Take prophylactic precaution when visiting a malarial area but make sure you get your medicine from a medical professional. Taking fake antimalarial medications or even the right stuff in the wrong doses may not prevent you from getting malaria. It may even help those malaria parasites to mutate and build up a resistance. Mosquito nets over beds are a good idea but then you must be sure to be in bed with the chickens because mozzies bite most during the dusk hour.
Not all mosquitoes carry malaria parasites. Only some of the female Anopheles mosquitoes do and they are easily identified by their resting position.
Resting positions of adult Anopheles (A) compared to a non-anopheline mosquito (B)