1. Malaria is caused by four species of Plasmodium parasites and transmitted via mosquito bites, infecting 400 million people annually and killing over 1 million. 2. Symptoms include fever, chills, and flu-like illness, with P. falciparum infections potentially causing severe complications like cerebral malaria and death if not promptly treated. 3. Diagnosis is by blood smear microscopy identification of the parasites, with treatment depending on parasite species but generally involving artemisinin combination therapies and primaquine for P. vivax and P. ovale to eradicate dormant liver stages preventing relapse.

1. Summary of Malaria &
Antimalarial therapy
Abdul Waris Khan
Soepel: 12
Internal medicine

2. Malaria
• Human malaria is usually caused by one of
four species of the genus Plasmodium:
– P. falciparum
– P. vivax
– P. ovale
– P. malariae

3. • Malaria probably originated from animal
malarias in Central Africa, but was spread
around the globe by human migration.
• Public health measures and changes in land
use have eradicated malaria in most
developed countries.

4. Epidemiology
• Some 400 million people are infected every year and
over 1 million die annually.
• 25 000 international travellers per year are infected.
• Australia, the USA and most of the Mediterranean are
malaria-free.
• Mortality is still mainly seen in infants, but older
children and adults may develop chronic ill health due
to repeated infections.

6. • Malaria is transmitted by the bite of female
anopheline mosquitoes.
• The parasite undergoes a temperature-dependent
cycle of development in the gut of
the insect.

10. Pathogenesis
• The pathology of malaria is related to anaemia, cytokine
release and in the case of P. falciparum, widespread organ
damage due to impaired microcirculation.
• The anaemia seen in malaria is multifactorial. In P.
falciparum malaria, red cells containing schizonts adhere to
the lining of capillaries in the brain, kidneys, gut, liver and
other organs.
• As well as causing mechanical obstruction these schizonts
rupture, releasing toxins and stimulating further cytokine
release.

12. Clinical features
• Typical malaria is seen in non-immune individuals.
• The normal incubation period is 10–21 days, but can be
• longer.
• The most common symptom is fever, although
• malaria may present initially with general malaise,
headache,
• vomiting, or diarrhoea.
• The temperature often reaches 41°C and is accompanied by
rigors and drenching sweats.

13. P. vivax or P. ovale infection
• The illness is usually relatively mild (although P. vivax can
occasionally cause severe disease).
• Anaemia develops slowly and there may be tender
hepatosplenomegaly.
• Spontaneous recovery usually occurs within 2–6 weeks, but
hypnozoites in the liver can cause relapses for many years
after infection.
• Repeated infections often cause chronic ill health due to
anaemia and hyperreactive splenomegaly.

14. P. malariae infection
• This also causes a relatively mild illness, but
tends to run a more chronic course.
• Parasitaemia may persist for years, with or
without symptoms.
• In children, P. malariae infection is associated
with glomerulonephritis and nephrotic
syndrome.

15. P. falciparum infection
• This causes, in many cases, a self-limiting illness similar to the other types of
malaria, although the paroxysms of fever are usually less marked.
• However, it may also cause serious complications and the vast majority of malaria
deaths are due to P. falciparum.
• Patients can deteriorate rapidly and children in particular progress from
reasonable health to coma and death within hours.
• A high parasitaemia (>1% of red cells infected) is an indicator of severe disease.
• Cerebral malaria is marked by diminished consciousness, confusion and
convulsions, often progressing to coma and death.
• Blackwater fever is due to widespread intravascular haemolysis, affecting both
parasitized and unparasitized red cells, giving rise to dark urine.

17. Diagnosis
• Malaria should be considered in the differential diagnosis of anyone
who presents with a febrile illness or having recently left, a
malarious area.
• Falciparum malaria is unlikely to present more than 3 months after
exposure, even if the patient has been taking prophylaxis, but vivax
malaria may cause symptoms for the first time up to a year after
leaving a malarious area.
• Diagnosis is usually made by identifying parasites on a Giemsa-stained
thick or thin blood film
• At least three films should be examined before malaria is declared
unlikely.

18. Treatment of uncomplicated malaria.
• The drug of choice for susceptible parasites is chloroquine.
• P. vivax, P. ovale and P. malariae are usually sensitive to this drug.
• Following successful treatment of P. vivax or P. ovale malaria, it is necessary to give
a 2- to 3-week course of primaquine (15 mg daily) to eradicate the hepatic
hypnozoites and prevent relapse.
• The artemisinin-based drugs are the most effective treatment for both
uncomplicated and severe infections with P. falciparum, in adults and in children.
• Artemisinin-based combination therapy (ACT) is the recommended oral treatment
for uncomplicated falciparum malaria worldwide.
• Artemisinin should not be given as monotherapy to limit resistance.
• The WHO recommends that a single dose of primaquine should be given as a
gametocide, to decrease transmission.

21. Treatment of severe falciparum malaria
• Severe malaria, indicated by the presence of the complications, or a
parasite count above 1% in a nonimmune patient, is a medical
emergency.
• Intravenous artesunate is more effective than intravenous quinine
and should be used where available.
• Absorption from intramuscular injection is less reliable than from
intravenous injection.
• Intensive care facilities may be needed, including mechanical
ventilation and dialysis.
• Severe anaemia may require transfusion.

23. Prevention and control
• Mosquito eradication is usually achieved either by the
use of insecticides, house spraying with DDT or by
manipulation of the habitat (e.g. marsh drainage).
• Non-immune travellers to malarious areas should take
measures to avoid insect bites, such as using insect
repellent (diethyltoluamide, DEET, 20–50% in lotions
and sprays) and sleeping under mosquito nets.
• Antimalarial prophylaxis should also be taken in most
cases, although they are not 100% effective.

26. References
• Kumar and Clark’s clinical medicine 8th edition