Malaria

Malaria is a tropical infectious disease that is caused by protozoan parasites. It is one of the most common infectious diseases and it causes enormous public health problems, especially in tropical and subtropical regions of Americas, Asia, and Africa. Each year, over 500 million people are infected with Malaria world wide, and between one and three million people are killed. The majority Malaria deaths are young children in Africa.

Malaria is commonly associated with poverty, because poorer people are more likely to become infected. However, Malaria is also a cause of poverty because it hinders economic development.

The same protozoan parasites that cause Malaria in humans can also infect birds, chimpanzees, monkeys, reptiles, and rodents. After Malaria was accidentally introduced to Hawaii by humans, it decimated the native birds of Hawaii because they had no natural resistance to the parasites.

Malaria Symptoms

The main symptoms of Malaria include:

o Anemia
o Arthralgia (joint pain)
o Chills / Shivering
o Convulsions
o Fever
o Flu-like symptoms
o Light headedness
o Nausea
o Shortness of breath
o Tingling in the skin
o Vomiting
o Abnormal posturing (especially in children)
o Brain Damage (especially in children)
o Cognitive impairment (especially in children)

The classical symptoms of Malaria are sudden coldness followed by rigor and then fever and sweating, which lasts for four to six hours and then recurs every two to three days.

Some of the above symptoms, such as anemia, light headedness, and shortness of breath, are caused because the protozoan parasites multiply inside red blood cells.

In severe cases, Malaria can cause:

  • Cerebral Ischemia
  • Coma
  • Hepatomegaly (Enlarged Liver)
  • Hypoglycemia
  • Kidney Failure, which may cause Blackwater Fever, where hemoglobin from red blood cells leaks into the urine
  • Severe Headache
  • Splenomegaly (Enlarged Spleen)

and eventually death.

Severe Malaria can progress extremely rapidly and cause death within hours or days. Such severe Malaria is almost exclusively caused by the protozoan parasite Plasmodium falciparum, where symptoms arises between six and fourteen days after infection.

Causes

Malaria is caused by a range of protozoan parasites of the genus Plasmodium, including:

  • Plasmodium falciparum
  • Plasmodium knowlesi
  • Plasmodium malariae
  • Plasmodium oval
  • Plasmodium vivax

The most serious form of the Malaria is caused by Plasmodium falciparum, which causes about 15% of Malaria infections and 90% of Malaria related deaths.

Plasmodium vivax is the most common cause of infection, and is responsible for approximately 80% of all Malaria cases

Transmission

The protozoan parasites that cause Malaria are transmitted to humans by the bite of the female Anopheles mosquito.

Treatment

No vaccine is currently available for Malaria.

However, medications are available which prevent Malaria, but they must be taken continuously to reduce the risk of infection.

Malaria infections are treated with anti-malarial medications, such as Quinine and Artemisinin derivatives. The first effective treatment for Malaria was the bark of Cinchona tree, which contains Quinine. This tree grows mainly in Peru.

The most serious form of the Malaria is caused by Plasmodium falciparum. Infections by this parasite are considered medical emergencies requiring hospitalization. Infection with the other parasites that cause Malaria can often be treated on an outpatient basis.

When properly treated in a timely manner, Malaria sufferers can expect a complete cure.

A range of issues confront Malaria treatment:

  • The protozoan parasites that cause Malaria are becoming increasingly resistant to many of the medications, such as Chloroquine.
  • These medications are usually too expensive for most of the people living where Malaria is common.
  • It is increasingly common to encounter sophisticated (and difficult to detect) counterfeit drugs being distributed and sold in Cambodia, China, Thailand, and Vietnam, and      these useless drugs are causing many death in these countries that would have been avoidable with the correct medications.

Further research is constantly being conducted into new and improved treatments for Malaria, including vaccine development.

Prevention and Control

The following techniques are used to attempt to prevent and control Malaria:

Insect Control: the primary prevention measure is mosquito eradication and control, which involves emptying pools of standing water (such as in the bases of flowerpots), spraying for mosquitoes, and applying larvicides (such as Abate) to standing water.

A fresh water crustacean, called Mesocyclops, can also be placed in water tanks and pools, and this organism eats and destroys the mosquito larvae. This solution is cheaper and far more environmentally friendly than pesticides, though not quite as effective. It also requires the ongoing participation of the local community.

Personal Protection: includes a range of measures, including covering exposed skin, using mosquito nets and screens on doors and windows, using insect repellents, and avoiding areas where female Anopheles mosquitoes are common.

Image: Chris Nurse, Wellcome Images

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