Malaria

What is malaria?

The word malaria comes from 18th century Italian mala meaning "bad" and aria meaning "air". Most likely, the term was first used by Dr. Francisco Torti, Italy, when people thought the disease was caused by foul air in marshy areas.

 

Mosquito having a blood meal. Image: google images

It was not until 1880 that scientists discovered that malaria was a parasitic disease which is transmitted by the anopheles mosquito. The mosquito infects the host with a one-cell parasite called plasmodium. By the end of the 18th century, scientists found out that Malaria is transmitted from person-to-person through the bite of the female mosquito, which needs blood for her eggs.

Approximately 40% of the total global population is at risk of Malaria infection. During the 20th century the disease was effectively eliminated in the majority of non-tropical countries.

There are five types of malaria:

• Plasmodium vivax (P. vivax) - milder form of the disease, generally not fatal. However, infected people still need treatment because their untreated progress can also cause a host of health problems. This type has the widest geographic distribution globally. About 60% of infections in India are due to P. vivax. This parasite has a liver stage and can remain in the body for years without causing sickness. If the patient is not treated, the liver stage may re-activate and cause relapses - malaria attacks - after months, or even years without symptoms.

•  Plasmodium malariae (P. malariae) - milder form of the disease, generally not fatal. However, the infected human still needs treatment because no treatment can also lead to a host of health problems. This type of parasite has been known to stay in the blood of some people for several decades.

• Plasmodium ovale (P. ovale) - milder form of the disease, generally not fatal. However, the infected human still needs to be treated because it may progress and cause a host of health problems. This parasite has a liver stage and can remain in the body for years without causing sickness. Without treatment there is a risk that the liver stage re-activates and cause relapses after very long periods without symptoms.

• Plasmodium falciparum (P. faliparum) - the most serious form of the disease. It is most common in Africa, especially sub-Saharan Africa. Current data indicates that cases are now being reported in areas of the world where this type was thought to have been eradicated.
• Plasmodium knowlesi (P. knowlesi) - causes malaria in macaques but can also infect humans.

How does a human become infected with malaria? 

·         The female Anopheles mosquito transmits the parasite to a human when it takes a blood meal - it bites the human in order to feed on blood.

·         Only the female Anopheles mosquito can transmit malaria, and it must have been infected through a previous blood meal taken from an infected human.

·         When the mosquito bites an infected person a minute quantity of the malaria (plasmodium) parasite in the blood is taken.

·         Approximately one week later that same infected mosquito takes its next blood meal. The plasmodium parasites mix with the mosquito's saliva and are injected into the host (human being).

Human-to-human transmission of malaria

As the parasite exists in human red blood cells, malaria can be passed on from one person to the next through organ transplant, shared use of needles/syringes, and blood transfusion. An infected mother may also pass malaria on to her baby during delivery (birth) - this is called 'congenital malaria'.

People cannot "catch" malaria from others just by being near them. You can sit next to an infected person quite safely, with no risk of infection, even if they cough or sneeze.

What are the symptoms of malaria? 

In regions where Malaria is common, local people usually have some level of immunity, which means that many infected people may have no symptoms at all, or very few.

Severity of Malaria symptoms depends on:

1. The type of parasite.
2. The individual's level of immunity.
3. Whether the person still has his/her spleen.

What are the treatment options for malaria?

According to WHO, in areas where Malaria is common treatment should start as soon as signs and symptoms appear, ideally within 24 hours.
People with uncomplicated malaria can be treated as outpatients, while those with severe malaria need to be hospitalized.
In non-endemic areas WHO recommends that patients with uncomplicated or severe malaria should be kept under clinical observation if possible.