Malaria and Mosquitoes
Malaria is a disease that is caused by various Plasmodium microorganisms. It is passed to humans and other vertebrates by mosquitoes, who are hosts to the malaria parasite. Malaria is a devastating disease, affecting over 219 million people in 2010. In that same year, it is reported that between 660,000 and 1.2 million people died of malaria. The vast majority of malaria victims are children in poverty-stricken regions of Africa and Asia.
Discovering the Correlation Between Malaria and Mosquitos
The term malaria comes from the italian words, ‘mala aira’ which means bad air. The disease had been associated with travel to a swampy or marshy area. In 1989, Sir Ronald Ross, a physician from Scotland, was able to complete the Plasmodium lifecycle in mosquitoes. For this discovery, Dr. Ross was awarded the Nobel Prize in 1902.
The Lifecycle of the Malaria Parasite and its Host
The malaria parasite, Plasmodium, is transmitted from a female mosquito (Anopheles) when she feeds. She transmits a sporozoite form of the parasite; a mobile, adult form that is almost ready to reproduce, into the new vertebrate host. This sporozoite travels through the blood stream to the liver. Once it reaches the liver it reproduces and the immature form that emerges is called a gamete. When a mosquito then bites an infected person, the gametes, which are in the blood stream, are taken along with the blood the mosquito eats. When the gamete reaches the belly of the mosquito, it matures and then travels to the mosquito’s salivary glands. From there, it is injected into a new host when the mosquito bites another vertebrate.
Malaria Risk Areas
- Mexico (moderate)
- Central America (moderate)
- South America (moderate to high)
- Southeast and Southwest Asia (high)
- Africa (high)
- Middle East (moderate to high)
Malaria was once prevalent in more northern hemisphere regions, but is rarely seen in these areas now.
Symptoms of Malaria
Malaria can be difficult to diagnose as its symptoms can mimic many other illnesses. Additionally, malaria can be dormant for a season, but symptoms may return at a later date. This is called a relapse. Malaria symptoms begin between 8 and 25 days after initial infection. The following is a list of malaria symptoms.
- severe weakness, inability to walk
- loss of consciousness or goes in and out of consciousness
- low blood pressure
- inability to eat
- difficulty breathing
- kidney failure
- circulatory shock
- two or more seizures
- pulmonary edema
If malaria is suspected, a blood test is needed to confirm it. However, many patients in high risk malaria locations are not able to afford this test or it is not possible due to lack of equipment or trained workers who can diagnose malaria. It is now common to treat a disease that is presenting as malaria, regardless of a positive malaria test.
The best way to prevent malaria is to get rid of mosquitoes or stop them from biting. Only female mosquitoes bite, and they most commonly feed in the evening so any campaign designed to eradicate malaria through lowering the number of mosquitoes or mosquito bites needs to focus on controlling nighttime insect behavior. Among the most popular and effective programs to lower malaria levels by controlling mosquitoes are:
- Introduction of mosquito nets for nighttime use
- Use of insect repellant
- Coating of walls with insecticide
- Eradication of stagnant water that attracts mosquitoes
Several groups exist today with the sole purpose of eradicating malaria. Currently there are a few malaria vaccines being developed and tested for future use. With control of mosquitoes and treatment of current malaria cases, complete eradication of this devastating disease is possible.