ASSESSMENT OF SOME TROPICAL DISEASES IN NIGERIA
MALARIA
Malaria is one of the most infectious diseases and an enormous public health challenge that has drawn the attention of government at all levels as well as private individuals the world over. Malaria is rated as one of the leading cause of mortality in the world.
Etymologically, the word ‘mal’ ‘aria’ is an Italian word which depicts bad air. It was first used in English language in 1740 by H.Walpole. ‘Mal’ ‘aria’ was then shortened to malaria in the 20th century. In 1880, C .Lavern was the first person to identify the parasite in human blood and later in 1889 R. Rose discovered that mosquitoes are the common vector of malaria.
Malaria is caused by a parasite called plasmodium. There are five species of plasmodium which affects humans. These are plasmodium vivas, p. falciparum, p. malariae, p.ovale, and p. knowlesi which is less common. Of these, plasmodium falciparum infection is the most severe and can cause death up to 10% of cases. It can be rapidly fatal. Pregnant women and children are especially at risk. Other types of malaria are less severe, but still may cause death.
How malaria is spread.
The parasite is transmitted to humans by the bite of infected female anopheles species mosquitoes. The parasite multiplies in the liver and blood stream of the infected. The parasite may be taken up by another mosquito when it bites an infected person. The mosquito is then infected for the duration of its life and can infect other humans when it bites them. Occasionally malaria is also transmitted through blood transfusion.
Signs and symptoms.
Signs and symptoms of malaria include fever which may come and go or may be constant, chills, profuse sweating, malaise (feeling of unwelness), muscle and joint pain, headache, confusion, loss of appetite, diarrhea, cough, anemia. It is important to note that plasmodium falciparum may cause cerebral malaria, a serious complication resulting from inflammation of the brain that may cause coma.
Diagnosis. Diagnosis of malaria is made by blood test, sometimes it’s necessary to repeat the test a number of time as the parasite can be difficult to detect.
Incubation period. This means the time between becoming infected and developing symptoms which varies with types. For instance
- P. falciparum is 9 to 14 days
- P.vivas is 12 to 18 days but some stains may have incubation period of 8 to 10 months or longer.
- P.ovale is 12 to 18 days
- P. malariae is 18 to 40 days and
- P. knowlesi is 9 to 12 days. These periods are approximate and may be longer if the person has been taking drugs taken to prevent infections.
Infectious period: It is noteworthy that there is no direct person to person spread of malaria. And a person remains infectious to mosquitoes as long as the parasites are present in the blood. This may be several years if adequate treatment is not given. Parasites disappear from the blood within few days of commencing appropriate treatment. Mosquitoes remain infected for life.
Prevention and control.
- By destroying the possible bleeding places.ie draining stagnant water in order to prevent the laying of eggs.
- By the use of insecticide to kill the adult mosquitoes or by killing them physically. I.e. through hands or using other objects.
- By spraying kerosene, other oil on water to reduce the surface tension and suffocate the larvae and pupae.
- By the introduction of fishes or ducks in the ponds to eat up the larvae, pupae and eggs of the mosquitoes.
- By sleeping inside insecticide treated net.
Treatment: Specific anti-malaria treatment is available and must always be started as soon as malaria is diagnosed. Examples of malaria drugs are Chloriquine, Amodiaquine, Pyrimethamine.