This document summarizes malaria, including that it is caused by Plasmodium parasites and transmitted by mosquitoes. It kills nearly 1 million people annually. Certain genetic mutations provide protection against severe malaria. Complications include splenomegaly and kidney disease. Diagnosis involves blood smears, and treatment depends on the Plasmodium species and drug resistance. Prevention involves drugs like doxycycline and mefloquine.
2. Malaria – ‘mal’ ‘aria’ = bad air
Malaria in humans - caused by Plasmodium falciparum, P.
vivax, P. ovale, P. malariae
Transmitted by the bite of female anopheles mosquitoes
The most important of the parasitic diseases of humans, it is
transmitted in 108 countries containing 3 billion people and
causes nearly 1 million deaths each year.
Worldwide distribution
3.
4. P. falciparum has influenced human evolution,
with the appearance of protective mutations such as
Sickle-cell anemia
Thalassaemia
G6PD deficiency
P. falciparum does not grow well in red cells that contain haemoglobin F, C or
S. these patients are protected against the lethal complications of malaria.
P. vivax cannot enter red cells that lack the Duffy blood group therefore many
West Africans and African-Americans are protected
5.
6.
7. 1. Tropical Splenomegaly (Hyperreactive Malarial Splenomegaly)
o Chronic or repeated malarial infections – splenomegaly
o An abnormal immunologic response to repeated infections characterized
by massive splenomegaly, hepatomegaly, marked elevations in serum IgM
and malarial antibody, hepatic sinusoidal lymphocytosis
2. Quartan Malarial Nephropathy
o Chronic or repeated infections with P. malariae may cause soluble
immune-complex injury to the renal glomeruli, resulting in the nephrotic
syndrome.
3. Burkitt's Lymphoma and Epstein-Barr Virus Infection
o Malaria-related immune dysregulation provokes infection with lymphoma
viruses
8. In the thick film, erythrocytes are lysed, releasing all blood stages
of the parasite. This, and the fact that more blood is used in thick
films, facilitates the diagnosis of low-level parasitaemia.
A thin film is essential to confirm the diagnosis, to identify the
species of parasite and, in P. falciparum infections, to quantify the
parasite load
Immunochromatographic tests for malaria antigens – most
sensitive in diagnosing falciparum sp.
Normochromic, normocytic anemia is usual
Reactive lymphocytosis and eosinophilia in the weeks after the
acute infection can be seen
Severe infections - prolonged PT and aPTT and by severe
thrombocytopenia
9. 1. P. falciparum – sensitive to chloroquine
A chloroquine dose of 600 mg base (= 1,000 mg salt) should be given
initially, followed by 300 mg base (= 500 mg salt) at 6, 24, and 48
hours after the initial dose for a total chloroquine dose of 1,500 mg
base (=2,500 mg salt).
2. P. falciparum – resistant to chloroquine
Artesunate (4 mg/kg body weight) daily for 3 days and sulfadoxine (25
mg/kg body weight) + pyrimethamine (1.25 mg/kg body weight) on
Day 0
This is to be accompanied by single dose primaquine (0.75 mg/kg
body weight) on Day 2.
10. 3. P vivax or P. ovale
Chloroquine in full therapeutic dose of 25 mg/kg divided over three
days
Primaquine 0.25 mg/kg body weight daily for 14 days (for clearing the
hypnozoites) – Should not be given in severely G6PD deficient
patients
4. Treatment of severe malaria
Artesunate: 2.4 mg/kg body weight i.v. or i.m. given on admission
(time=0), then at 12 hours and 24 hours, then once a day
OR
Quinine: 20 mg quinine salt/kg body weight on admission (i.v. infusion
in 5% dextrose/dextrose saline over a period of 4 hours) followed by
maintenance dose of 10 mg/kg body weight 8 hourly;
Infusion rate should not exceed 5 mg/kg body weight per hour.
Loading dose of 20 mg/kg body eight should not be given, if the
patient has already received quinine.
11. 1. Short term (<6 weeks)
Doxycycline: 100 mg daily.
The drug should be started 2 days before travel and continued for 4
weeks after leaving the malarious area
2. Long term (>6 weeks)
Mefloquine: 5 mg/kg body weight (up to 250 mg) weekly and should
be administered two weeks before, during and four weeks after
leaving the area.