Malaria (Plasmodium Infection)
Malaria is a disease caused by a plasmodium parasite, transmitted by the bite of infected mosquitoes. Malaria is also called plasmodium infection and it is preventable and curable.
Malaria in Human is caused by four distinct species of malaria parasite-
1. Plasmodium vivax
2. Plasmodium falciparum
3. Plasmodium malariae
4. Plasmodium ovale
Malaria is a disease caused by Plasmodium parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes.
Plasmodium vivax and Plasmodium falciparum has the widest geographic distribution throughout the world.
1. Urban malaria – Anopheles stephensi is a primary mosquito vector of malaria in urban India.
2. Rural malaria– Anopheles culicifacies is widely distributed transmission in india.
3. Tribal malaria– General vector involved in transmission is Plasmodium falciparum.
Note – Don’t confuse with Filariasis disease. Filariasis is a parasitic disease caused by filarial worms, spread by infected mosquitoes.
Epidemiological Triad
Agent – Malaria is caused by four distinct species;
1. Plasmodium vivax
2. Plasmodium falciparum
3. Plasmodium malariae
4. Plasmodium ovale
In india 70% of cases occur due to plasmodium vivax.
Host – Malaria affect all ages and affect both sexes. Children under age of 5 years are the most vulnerable group affected by malaria.
Pregnant women are risk
Humans are their only relevant reservoir for malaria
Environment– Rainfall, wind, temperature; optimal temperature in the insect vector required for the development of parasites is 20°C to 30°C,
Humidity, Irrigation channels, Garden pools, Stagnant water in coolers
Mode of Transmission
Malaria is caused by protozoan parasites Plasmodium. The parasites are spread to human through the bites of infected female Anopheles mosquitoes, called “malaria vectors’.
The parasites are spread to human through the bites of infected female Anopheles mosquitoes. Transmission occurs from infected person to healthy person by vector transmission (Anopheles mosquito).
1. Mosquito to Man
2. Man to Mosquito to Man
Malaria is transmitted by blood, so it can also be transmitted through-
1. Direct transmission
a. Blood transfusion
b. Organ transplant
C. Needlestick injury
D. Sharing of needles of infected drug addicts
2. Congenital – Infected mother to new born
Exposure to malaria during pregnancy may result in fatal.
Malaria can be transmitted from a infected mother to her unborn infant before or during delivery (congenital malaria).
If parasites are transmitted pass the placenta that could be result in congenital malaria. Plasmodium falciparum was the only main parasite species that present in the umbilical cord blood.
Incubation period
The incubation period of –
1. Plasmodium vivax – 8-17 days
2. Plasmodium falciparum – 9-14 days
3. Plasmodium malariae – 18-40 days
4. Plasmodium ovale – 16-18 days
Pathophysiology of Malaria
1. Human gets bite from an infected Mosquito
2. Parasite start reproducing in the liver and some parasites remaining dormant for years before becoming activated
3. In the bloodstream further reproduction occurs within red blood cell (erythrocytes)
4. Parasite reproduction result in further red blood cell infection
5. Cycle of red blood cell infection and destruction
6. Occurs fever and chills
The life cycle of Plasmodium species divided into two distinct phases-
1. The asexual cycle in humans and
2. The sexual cycle in mosquitoes
1. Female mosquito anopleles bite an infected person and gametocytes are ingested.
2. Inside the mosquito body, sexual cycle occurs led to the development of parasite from gametocyte to sporozoite stage in 10-20 days under favourable condition.
3. When this infected mosquito bites a person, injects sporozoits.
4. Asexual cycle in humans Sporozoites turn into merozoites
5. Man is the reservior of agent of malaria
Man – Intermediate host
Mosquito – Definitive host
Sporozoites are infective form, it present in the salivary of female anopheles mosquito
After bite of infected mosquito sporozoites are introduced into blood circulation.
Clinical Manifestation
Malaria is an acute febrile illness. In individuals, symptoms usually appear 10–15 days after the infective mosquito bite.
1. Fever with chills, rigors
2. Headache
3. Vomiting
4. Nausea
5. Tachycardia
6. Tachypnea
7. Sweating
Children with severe malaria frequently develop one or more of the symptoms-
1. Severe anaemia (Caused by haemolysis)
2. Respiratory distress
3. Hepatosplenomegaly
4. Cerebral malaria -Most severe neurological complication due to infection with Plasmodium falciparum malaria.
5. Congenital malaria
Attack of Malaria Stages
Paroxysmal attack of Malarial found in Three Stages, with clinical manifestations are –
1. Cold Stage
2. Hot Stage
3. Sweating Stage
1. Cold Stage
Headache, nausea, chills, fever rise rapidly, vomiting, tachycardia,
2. Hot Stage
Feel burning hot, Skin hot and dry, Tachypnea
3. Sweating Stage
Temperature decreases with Sweating, Skin cool and moist
Complications of Malaria
1. Cerebral malaria – coma, altered mental status, or multiple fits (seizures) or coma (convulsion)
2. Liver failure and jaundice – yellowing of skin and whites of eyes
3. Shock – a sudden drop in blood pressure
4. Pulmonary oedema – a build-up of fluid in the lungs
5. Acute respiratory distress syndrome – associated with severe P. falciparum malaria
Malaria in Pregnancy
If infected malaria while pregnant, get an increased risk of developing serious complications, such as-
1. Premature birth – birth before 37 weeks of pregnancy
2. Low birth weight
3. Restricted growth of the baby in the womb
4. Stillbirth – when a baby is born dead after 24 completed weeks of pregnancy
5. Miscarriage
Laboratory Diagnosis
1. Malaria Blood Smear – checked for malaria parasite. Two types of blood films are prepared-
a. Thin film
b. Thick film
2. Serology test
3. Polymerase chain reaction (PCR)
4. Malaria drug resistance test
5. The peripheral smear
6. Bone marrow smear
7. CBC complete blood count test; including red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs),
TC (total count; measures the number of white blood cells)
DC (blood differential test; detect abnormal or immature cells)
Treatment – Antimalarial Drugs
Antimalarial drugs can also be used to prevent malaria disease.
The treatment of a suspected and clinical case of malaria according to drug policy for malaria under National- malarial programme is presumptive treatment and radical treatment.
Presumptive therapy – only given to febrile patients. Presumptive treatment of all suspected malaria.
Radical treatment – Extensive or complete therapy individuals with confirmed either Plasmodium vivax or Plasmodium ovale.
To elimination of dormant liver stage parasites (hypnozoites) found in Plasmodium vivax and Plasmodium ovale.
Prevention and Control
1. Early diagnosis and Treatment
2. Chemoprophylaxis – Take recommended antimalarial drugs to prevent acute malaria attacks. For travelers, malaria can be prevented through chemoprophylaxis, which suppresses the blood stage of malaria infections and preventing malaria disease.
3. Mass drug administration – Administration of antimalarial treatment to every person living in a defined geographical area.
4. Mosquito control measures – Malarial Vector control is the main way to prevent and reduce malaria transmission with effective malaria vector control.
a. Anti-larval measure
b. Anti-adult measures
5. Protection against mosquito
6. Reduction of mosquito breeding
7. Anti-malarial programme
Vaccines Against Malaria
Malaria vaccine is a vaccine, used to prevent malaria.
Only approved vaccine is RTS,S/AS01 (Mosquirix) – It acts against Plasmodium falciparum. It defend against the first stages when the Plasmodium falciparum malaria parasite enters the human host’s bloodstream through a mosquito bite and infects liver cells.
Antimalarial Drug Resistance
Antimalarial drug resistance is the ability of a strain of parasite to survive and/or to multiply despite the administration and absorption of medicine is given in doses equal to or higher than those usually recommended.
Resistance of malaria parasites arises from various factors-
1. Overuse of antimalarial drugs for prophylaxis
2. Inadequate or incomplete therapeutic treatments of active infections
3. Resulted from a high level of parasite adaptability at the genetic and metabolic levels.
Get the information here sign and symptom of dengue fever, it is a mosquito-borne viral disease.
