Malaria Definition Symptoms Types Prevention Treatment And Management Of Complicated Malaria

Definition:

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists (a type of microorganism) of the genusPlasmodium. 

When People Get Malaria:

Usually, people get malaria by being bitten by an infected female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person.When a mosquito bites, a small amount of blood is taken in which contains the microscopic malaria parasites. The parasite grows and matures in the mosquito's gut for a week or more, then travels to the mosquito's salivary glands. When the mosquito next takes a blood meal, these parasites mix with the saliva and are injected into the bite.Once in the blood, the parasites travel to the liver and enter liver cells to grow and multiply. During this "incubation period", the infected person has no symptoms. After as few as 8 days or as long as several months, the parasites leave the liver cells and enter red blood cells. Once in the cells, they continue to grow and multiply. After they mature, the infected red blood cells rupture, freeing the parasites to attack and enter other red blood cells. Toxins released when the red cells burst are what cause the typical fever, chills, and flu-like malaria symptoms.If a mosquito bites this infected person and ingests certain types of malaria parasites ("gametocytes"), the cycle of transmission continues.Because the malaria parasite is found in red blood cells, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her fetus before or during delivery ("congenital" malaria).Malaria is not transmitted from person to person like a cold or the flu. You cannot get malaria from casual contact with malaria-infected people.

Sign And Symptoms:

• Fever,
• Shivering,
• Arthralgia (joint pain),
• Vomiting,
• hemolytic anemia,
• Jaundice
• Hemoglobinuria,
• Retinal damage
• Convulsions
• Enlarged splee

Type Of Malaria:
There are four types of human malaria .

• Plasmodium vivax.
• Plasmodium ovale 
• Plasmodium falciparum.
• Plasmodium   malariae  

Diagnosis:

Microscopy of stained thick and thin blood smears remains the gold standard for confirmation of diagnosis of malaria.
The advantages of microscopy are:

•  The sensitivity is high. It is possible to detect malarial parasitesat low densities. It also helps to quantify the parasite load.
•  It is possible to distinguish the various species of malaria parasite and their different stages.

 Rapid Diagnostic Test:

Rapid Diagnost ic Tests are based on the detect ion of circulating parasite antigens. Some of them can only detectP. falciparum, while others can detect other parasite species also.The latter kits are expensive and temperature sensitive. Presently,NVBDCP supplies RDT kits for detection of P. falciparum at locations where microscopy results are not obtainable within 24 hours of sample collection.

Prevention:

• keeping mosquitoes from biting especially at night
• taking antimalarial drugs to kill the parasites
• eliminating places around  home where mosquitoes breed.
• spraying insecticides on home's walls to kill adult mosquitoes that come inside
• sleeping under bed nets - especially effective if they have been treated with insecticide.
• wearing insect repellent and long-sleeved clothing if out of doors at night.

Treatment:

Plasmodium vivax:

Positive P. vivax cases should be treated with chloroquine in full therapeutic dose of 25 mg/kg divided over three days. Vivax malaria relapses due to the presence of hypnozoites in the liver.The relapse rate in vivax malaria in India is around 30%. For its prevention, primaquine may be given at a dose of 0.25 mg/kg daily for 14 days under supervision. Primaquine is contraindicated in G6PD deficient patients, infants and pregnant women.

Plasmodium falciparum. :

The treatment of P. falciparum malaria is based on area identified as chloroquine resistant/ sensitive . Artemisinin Combination Therapy (ACT) should be given in resistant areas whereas chloroquine can be used in sensitive areas. ACT should be given only to confirmed P. falciparum cases found positive by microscopy or RDT.ACT consists of an artemisinin derivative combined with a long acting antimalarial (amodiaquine, lumefantrine, mefloquineor sulfadoxine-pyrimethamine). The ACT used in the national programme in India is artesunate + sulfadoxine-pyrimethamine (SP). Presently, Artemether + Lumefantrine fixed dose combination and blister pack of artesunate + mefloquine are also available in the country. Other ACTs which will be registered and authorized for marketing in India may be used as alternatives.

Management of complicated malaria:

Of the various complications of falciparum malaria the common and important ones as follows:

•  Cerebral malaria

Initial presentation is usually fever followed by inability to eat or drink. The progression to coma or convulsion is usually very rapid within one or two days. Convulsions may be very subtle with nystagmus, salivation or twitching of an isolated part of the body. Effort should be given to exclude other treatable causes of coma (e.g., bacterial meningitis, hypoglycemia). Patients should be given good nursing care, convulsions should be treated with diazepam/midazolam and avoid harmful adjuvant treatment like corticosteroids, mannitol, adrenaline and phenobarbitone.

•  Severe anemia

 With hyperparasitemia due to acute destruction of red cells may develop severe anemia. Packed red cell transfusion should be given cautiously when PCV is 12% or less, or hemoglobin is below 4g%. Transfusion should also be considered in patients with less severe anemia in the presence of respiratory distress (acidosis), impaired consciousness or hyperparasitemia (>20% of RBCs infected).

•  Respiratory distress (acidosis)

Deep breathing with indrawing of lower chest wall without any localizing chest signs suggest lactic acidosis. It usually accompanies cerebral malaria, anemia or dehydration. Correct hypovolemia, treat anemia and prevent seizures. Monitor acid base status, blood glucose and urea and electrolyte level.

•  Hypoglycemia 

It is common in children below 3 years specially with hyperparasitemia or with convulsion. It also occurs in patients treated with quinine. Manifestations are similar to those of cerebral malaria so it can be easily overlooked. Monitor blood sugar every 4 to 6 hours. If facilities to monitor blood glucose is not available assume hypoglycemia in symptomatic patient and treat accordingly. Correct hypoglycemia with IV dextrose (25% dextrose 2 to 4 mL/kg by bolus) and it should be followed by slow infusion of 5% dextrose containing fluid to prevent recurrence.

• Circulatory collapse (Algid malaria)

In case of circulatory collapse suspect gram negative septicemia, send blood for culture before starting antibiotics. Resuscitate with judicious use of fluids.