Malaria: Symptoms, Mode of Transmission, Treatment and Prevention

Malaria: Malaria is a major international public health problem, causing 350–500 million infections worldwide and approximately 1 million deaths annually. Malaria in humans is caused by 1 of 4 protozoan species of the genus Plasmodium: Plasmodium falciparum, P. vivax, P. ovale, or P. malariae. In addition, P. knowlesi, a parasite of Old World (Eastern Hemisphere) monkeys, has been documented as a cause of human infections and some deaths in Southeast Asia.

Sign and Symptoms:
1. As the malaria parasites enter the blood stream they infect and destroy red blood cells. 

2. Destruction of these essential cells leads to fever and flu-like symptoms, such as chills, headache, muscle aches, tiredness, nausea, vomiting and diarrhea. 

3. These initial symptoms are non-specific: in other words, they are self-reported symptoms that do not indicate a specific disease process.

Mode of Transmission:
All species are transmitted by the bite of an infective female Anopheles mosquito. Occasionally, transmission occurs by blood transfusion, organ transplantation, needle sharing, or congenitally from mother to fetus.

Treatment:
1. You can take medicines called antimalarials to prevent and treat malaria. Malaria is a very serious disease, and its presence in many regions of the world is well known. So if you are traveling to an area where malaria is present, it is important to consider taking medicine before you travel, while you are in the area, and after you return home to reduce the risk of infection. Which medicine you take is based on:
*The country or areas in which you will be traveling.
*The resistance of malaria parasites to certain medicines in the area where you will be traveling.
*Your health condition (for example, you are pregnant, elderly or young, sick, or have immunity or resistance to malaria).

2. It is important to know which species of parasite is present, because serious complications may develop rapidly in a person who is infected with Plasmodium (P.) falciparum. Drug treatment is based on:

* The species of parasite. If you are infected with P. falciparum, life-threatening complications can develop rapidly. Infection caused by one of the other three species of malaria is rarely life-threatening.
* The density of parasites. If the percentage of red blood cells infected (parasite density) is over 5%, treatment may include medicines given directly into a vein (intravenously, or IV) rather than medicine taken by mouth.
* Your health condition. You are at higher risk for having complications if you are pregnant, elderly, very young, or have a weak immune system. Different medicines may be prescribed for people in these groups.
* Drug resistance in the geographic area where the infection occurred. For instance, in many areas P. falciparum is resistant to the drug chloroquine.

3. During malaria treatment, your doctor may do daily blood smears to follow the course of the infection. Most medicines for malaria are ones you take by mouth. But you might get intravenous (IV) medicines if there are complications or your condition gets worse. If there are no complications, your fever will clear in 36 to 48 hours. And most parasites will disappear from your blood within 2 or 3 days.

4. The medicines used may change as malaria parasites develop resistance and as new medicines are developed.

Prevention and Control:

 
1. Prevent mosquito bites :To prevent mosquito bites, follow these guidelines:
1.1 Stay inside when it is dark outside, preferably in a screened or air-conditioned room.
1.2 Wear protective clothing (long pants and long-sleeved shirts).
1.3 Use insect repellent with DEET (N,N diethylmetatoluamide). 1.4 The repellent is available in varying strengths up to 100%. In young children, use a preparation containing less than 24% strength, because too much of the chemical can be absorbed through the skin.
1.5 Use bed nets (mosquito netting) sprayed with or soaked in an insecticide such as permethrin or deltamethrin.
1.6 Use flying-insect spray indoors around sleeping areas.
1.7 Avoid areas where malaria and mosquitoes are present if you are at higher risk (for example, if you are pregnant, very young, or very old).

2. Other steps that may be helpful in reducing the risk of malaria include using air conditioning and electric fans, wearing protective clothing, using aerosol insecticides in your house, and taking certain antimalarial medicines.
2.1 Medicines to prevent malaria
The selection of medicines to prevent malaria depends on the geographic region where you may be exposed to malaria and your health condition (such as being pregnant, being elderly or young, being sick, or having immunity or resistance to malaria, or having allergies or sensitivity to the medicine).

2.2 If you are going to a location where malaria is present, it is very important to take preventive medicines and to follow the correct schedule for taking them. The majority of people who become infected with malaria do not take preventive malaria medicines or do not follow the correct dosing schedule.
2.3 Medicine to prevent malaria is most effective if you take the recommended dosage exactly as prescribed and for the length of time required.
2.4 If you are to take the medicine once a week, take it on the same day of the week each week.

2.5 Upon returning from an area where malaria is present, continue the medicine for the recommended length of time to ensure that all parasites have been eliminated from your body. You will need to take the medicine for 1 to 4 weeks after returning.
Malaria vaccines

2.6 Scientists are studying malaria vaccines to see whether the vaccines are effectively preventing malaria infection. But no vaccine has been approved to prevent malaria.