Malaria is one of the most widespread diseases by the protozoan parasite of the genus Plasmodium and is most commonly transmitted through the bite of the female anopheles mosquito. These parasites spend an asexual phase in humans and a sexual phase in female anopheles mosquitoes.
Every year about 200 million cases of malaria occur throughout the world with millions of deaths. However, the incidence, as well as the death rates, have fallen since the year 2000 due to extensive control programs and the active role of the WHO with about 198 million cases and nearly 6 lakh deaths in 2013. It is a major public health problem in most developing countries including India with about 5 lahks confirmed cases of malaria reported in 2013 in India.
MALARIA IS CAUSED BY?
Malaria is caused by species of one-cell protozoan of the Plasmodium genus
MALARIA MOSQUITO:
There are mainly 5 species of the malarial parasite. They are,
1. Plasmodium falciparum:
• causes the most severe form of malaria (malignant tertian) which can be fatal.
• 90% of deaths due to malaria are due to P. falciparum. The parasite in the RBCs
requires about 48 hours to complete its life cycle and ruptures every 3rd day
(hence the name tertian) and this results in fever.
• In the later stages of the erythrocytic cycle of the parasite, the infected
erythrocytes get sequestered in capillaries, i.e. they pack the capillaries of
various tissues resulting in tissue anoxia particularly cerebral anoxia making it
lethal malaria. However, relapses do not occur because P. falciparum doesn’t
have the exoerythrocytic stage in their life cycle.
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2. Plasmodium vivax:
• causes less severe malaria (benign tertian) with a lower mortality rate.
Relapses can occur because of the exoerythrocytic forms or hypnozoites.
3. Plasmodium ovale:
• It is mostly seen in Africa, causes a milder form of malaria similar to P. vivax and
relapses can occur.
4. Plasmodium malariae:
• also causes malaria of a milder type similar to P. vivax (benign quartan) with no
exoerythrocytic cycle. The febrile attack is seen every fourth day because 72 hours
are needed for the maturation of the parasite in the RBCs and it is, therefore,
called quartan malaria.
5. Plasmodium knowlesi:
• It is zoonotic malaria acquired from macaque monkeys and has been
increasingly reported in South-East Asian countries like Thailand, Malaysia, and Vietnam. It has a 24-hr erythrocytic cycle with fever occurring every day.
MALARIA SYMPTOMS:
The symptoms of malaria include
• Fever with chills
• Myalgia(muscle pain)
• Arthralgia (joint pain)
• Headache
• Vomiting and nausea
• Fatigue
• Diarrhoea
• Abdominal pain
• Dizziness
• Night sweats
• Shivering
• Dry cough
• Bloody stools
• Hypotension
• In sever forms convulsions
• Mild anemia
• Rapid breathing
• Splenomegaly(enlargement of spleen)
• Mild hepatomegaly(enlargement of liver)
• Mental confusion
• Fast heart rate
LIFE CYCLE OF MALARIA:
• Life cycle of malaria The mosquito stores the sporozoite form of the protozoan in its salivary glands Malarial infection is initiated through the bite of an infected mosquito into the human bloodstream.
• The sporozoites present in the bloodstream then enter into the parenchyma cell of the host liver, where they become primary schizonts and then merozoites.
• Depending upon the plasmodium the merozoites either will rupture the infected
hepatocytes and enter the blood circulation or infect other liver cells.
• Merozoite then enters into the blood circulation and destroyed the erythrocytes,
where they residue for 3 to 4 days and then reproduce. The reproduction stage in
the erythrocyte can able to produce either more merozoites or another form called
gametocytes.
• Due to this repeated multiplication erythrocytes may get rupture and release
merozoites into blood circulation.
• Each merozoite forms again will invade fresh erythrocytes and the cycle of asexual multiplication is repeated again. This stage is particularly known as the schizogony phase of the infection which leads to cause severe fever and chills.
• Such infected blood was ingested by the female anopheles mosquito, the
gametocytes (male and female) undergo sexual reproduction within the gut of the
insect thus resulting in the formation of zygotes through there are various stages of development and migrate as sporozoites into the mosquito salivary gland. The cycle repeats when a mosquito bites a human.
MODE OF TRANSMISSION OF MALARIA:
• Most commonly transmitted through the bite of a female anopheles mosquito
• Transmitted by blood transfusion and vertically from the mother to the fetus across
the placenta
• Also Transmitted by sharing needles which are used to inject drugs
RISK FACTORS:
• Travelling in a region where malaria is present. These may include tropical and
subtropical regions of sub-Saharan, Central America, south and Southeast Asia,
Northern South America
• Pregnant women
• Children under the age of 5 years
• Patients with HIV/AIDS
• Living in unhygienic places
COMPLICATIONS OF MALARIA:
• Breathing problems
• Cerebral malaria
• Kidney damage
• Liver damage
• Spleen damage
• Anemia
• Low blood sugar
• Shock
• Pulmonary edema
• Acute respiratory distress syndrome
• Metabolic acidosis
• Miscarriage
• Altered consciousness
PREVENTION OF MALARIA:
1. By use of the antimalarial agents
2. By protecting from mosquitoes. In order to avoid mosquito bites the following steps are recommended
• Apply insect repellent cream to an exposed skin
• Wear long-sleeved clothing
• Keep your surroundings hygienic
• Use a mosquito net all over the bed
• Put mosquito screens on windows and doors
• Avoid the use of scented soaps
• Keep home clean
• Drain the water reservoir regularly
• Close the water reservoir properly
• Avoid storage of water in pots, coolers in tanks
HOME REMEDIES:
1. Turmeric: shows antimalarial activity
2. Grapefruit
3. Ginger: which controls nausea and vomiting
4. Citrus fruits
5. Drink lukewarm water
6. Cinnamon: shown inhibitory action against the malarial parasites
7. Tulsi: shown antimalarial activity and boost the immune system to fight against the pathogens
8. Neem: helps to reduce the fever and boost the immune system
9. Coconut water: helps in balancing fluid in the body which prevents dehydration.
DIAGNOSIS OF MALARIA:
1. Physical examination: by asking questions about the symptoms
2. Blood test: the blood test will help to detect the presence of malarial parasite and
the type of plasmodium is causing the symptoms
TREATMENT OF MALARIA:
• Causal prophylactics: destroy the parasite in the liver cells and prevent invasion of erythrocytes. Eg-primaquine, pyrimethamine
• Chloroquine phosphate: chloroquine enters the BBC cells and then into the food vacuole of the parasite and causes the death of the parasite
• Doxycycline Hyclate
• Mefloquine
• Atovaquone proguanil
What is the name of the world’s first malaria vaccine?
The malaria vaccine is those which is used to prevent malaria. RTS, S by the brand name Mosquirix is an approved malaria vaccine used nowadays.