• Shruti GOCHHWAL

Malaria

Malaria is an endemic disease which is spread through the bite of a mosquito. According to the World Health Organization, an estimated 228 million cases of malaria were there in the year 2018 along with more than 4 lakh deaths.

To fight the disease various countries along with organizations such as the WHO spent US$ 2.7 billion in 2018 to control and eliminate malaria. World malaria day is observed on April 25th every year to create awareness and recognize global efforts that are made to eradicate malaria. More than 90% of cases are reported in the continent of Africa.

What is the Cause of Malaria?

When an infected female anopheles mosquito bites a human, it releases plasmodium protozoa into the body. These plasmodium protozoa are the cause of malaria.

The incubation period varies depending on the parasite which has caused malaria.

The transmission of malaria occurs through the blood and it can also be transferred from an infected individual to a healthy one through the following:

● Organ transplant

● Blood transfusion

● Using shared needles and syringes.

Types of Malaria

Malaria is classified based on the parasite that causes it.

● Plasmodium Falciparum: It is a very serious form of malaria that requires immediate treatment. It is prevalent in all endemic affected regions. The incubation period is 9-14 days.

● Plasmodium Vivax: This form of malaria is found in South America and Asia. It has a delayed onset. It has an incubation period of 8-17 days.

● Plasmodium Malarie: It is a quartan form of malaria. Plasmodium malaria is a moderate form of malaria which mostly affects South America and Asia. The incubation period is 16-18 days.

● Plasmodium Ovale: This type of malaria is prevalent in Africa. It is a moderate form of malaria. The incubation period ranges between 18-40 days.

● Plasmodium Knowlesi: This is limited to south-east Asia. It is a very serious type of malaria and can be fatal if not treated effectively. It can have a very large incubation period ranging from 18-90 days.

Malaria Symptoms

Credits: Pixabay Caption: The most common symptom of malaria is a high fever.

Malaria can have the following symptoms

● Chills

● High fever

● Nausea

● Pain in muscles

● Diarrhoea

● Bloody stool

● Increased sweating

● Convulsions

● Headache

Malaria Symptoms in Toddlers

The most affected age group by malaria is 0-5 years. This age group accounts for 67% of the total deaths caused by malaria and requires special attention. If malaria is suspected in toddlers then immediate medical intervention is necessary.

Toddlers can have the following additional symptoms of malaria

● Increased irritability

● Loss of appetite

● Tiredness

Credits: Pixabay Caption: Malaria is much more dangerous for children up to five years of age.

Life Cycle of Malaria

The life cycle of malaria is the mechanism that the sporozoites follow in causing malaria. It is a complex cycle as it acts in the human as well as the mosquito. The cycle is as follows:

● The infected female anopheles mosquito bites a human being and injects sporozoites which are also called Plasmodium parasites into the blood.

● These sporozoites enter the human liver and multiply over the next 7 to 10 days.

● After multiplication, the sporozoites travel to other parts of the body and disintegrate into merozoites.

● These merozoites enter the blood and attack erythrocytes and enter into them.

● Merozoites multiply until the erythrocytes burst to release them into the bloodstream where they attack more erythrocytes.

● Some of the merozoites undergo sexual reproduction and transform into gametocytes which are present in the blood.

● If an infected person is bitten by the mosquito then the mosquito ingests gametocytes.

● The gametocytes mature into cells called gametes.

● These cells burrow in the gut wall of the mosquito in the form of oocysts.

● The oocysts burst releasing sporozoites.

● The sporozoites reach the salivary glands of the mosquito.

● When this mosquito bites a human being, it transfers the sporozoites and the cycle is repeated.

Pathogenesis of Malaria

Pathogenesis is defined as the manner in which the disease develops. The exact process which happens is explained in the life cycle of malaria.

The symptoms start to appear when the rupture of the erythrocytes takes place. Fever and chills appear at this stage.

In severe cases of falciparum malaria, some infected cells obstruct the capillaries which lead to hypoxia and other complications. It can also result in obstruction of the microcirculation of the brain.

Diagnosis of Malaria

The diagnosis of malaria is challenging as specific signs are not initially present. Symptoms of malaria and dengue are similar. Various other bacterial infections also have similar symptoms. In severe cases of malaria, the presence of symptoms makes the diagnosis easier.

The clinical findings that are found by the doctor using a physical exam and patient history should be confirmed with a laboratory test. The following are malaria test names:

● Blood smear test: These are simple tests in which the blood of the patient is treated with a reagent and viewed under a microscope. The quantity of malaria parasites changes rapidly and this test can give a false negative.

Credits: Pixabay Caption: Commonly used diagnostic test for malaria is blood smear test.

● Polymerase Chain Reaction Test: The polymerase chain reaction test can identify the type of malaria. It is a very important test as it helps the doctor in selecting a treatment plan and understanding the severity of the condition.

● Rapid Diagnostic Test: This test is very quick and works by making a small prick on your finger and analyzing the blood. The blood is put on a test strip which shows a change in colour indicating whether malaria is present or not. This test does not determine the type of malaria.

● Antibody Test: Antibodies are created by the body to fight specific diseases. The presence of antibodies shows that the disease has affected the person in the past.

● Drug Resistance Test: There are some parasites which are resistant to particular drugs. This test helps in choosing the right drug.

Treatment of Malaria

The medications for malaria can be classified on the basis of which stage of the life cycle of malaria they act on.

● Causal Prophylaxis: These act on the pre-erythrocytic stage. Proguanil is the drug of choice. This form of treatment is not widely used in India.

● Suppressive Prophylaxis: This is used mostly for travellers who are travelling from non-endemic regions to endemic regions. Mefloquine and doxycycline are widely used.

● Clinical Cure: These drugs are used to end an episode of malaria. Amodiaquine and chloroquine are examples of drugs which are used.

● Radical Cure: These are the drugs which are used when malaria keeps relapsing. They are used in plasmodium vivax and plasmodium ovale. Primaquine is used for 15 days.

● Gametocidal: This form of treatment removes the gametes that are formed in the blood of the patient. A single 45mg dose of primaquine is recommended as a gametocidal.

Complications of Malaria

Malaria can cause various life-threatening complications if left untreated. These complications are serious medical conditions and require immediate medical help.

● Cerebral Malaria: Cerebral malaria is a condition in which the blood vessels of the brain swell up. The exact mechanism of how it occurs is not known but this condition is fatal. Cerebral malaria symptoms include dizziness, delirium, impaired consciousness and abnormal neurological function.

● Organ Failure: Malaria can cause multiple organ failure. The liver and kidney are examples of organs which can fail due to malaria.

● Anaemia: Malaria destroys red blood cells, which in turn, can cause anaemia.

● Pulmonary Edema: When fluid gets accumulated in the lungs, it is known as pulmonary oedema.

Malaria in India

Malaria is prevalent in India but the number of cases is decreasing. According to the World Health Organization, India had a 51% decrease in the total number of cases from 2017 to 2018. The National Strategic Plan for Malaria Elimination 2017-2022 is the biggest domestic plan by any country in the world in terms of direct investment. The government of India has set up various institutions such as the National Institute of Malaria Research to help eradicate this disease from India.

India observes June of every year as anti-malaria month to raise awareness about the disease and do activities which work towards eliminating malaria from the country.

Malaria prevention focuses primarily on reducing mosquito bites as that is considered the most effective technique. Other forms of prevention include creating awareness and increasing the availability of diagnostic and treatment options for malaria.

Takeaway

Malaria is a serious medical condition which requires treatment. If you have symptoms of malaria see a doctor. There are various drugs available which can be used to treat malaria.

Malaria is a preventable condition. Argentina and Algeria have recently been declared as malaria-free countries by the World Health Organization. India, too, is aiming to be a malaria-free country in the coming years.

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