A brief description about malaria its causes, epidemiology, life cycle of parasite, symptoms, diagnosis and its treatment

1. Malaria
Ravi Kumar
Group : 2

2. Introduction
 Malaria is a disease caused by a parasite, transmitted by the bite of
infected mosquitoes. Malaria produces recurrent attacks of chills
and fever. Malaria kills an estimated 660,000 people each year.
 While the disease is uncommon in temperate climates, malaria is
still prevalent in tropical and subtropical countries. World health
officials are trying to reduce the incidence of malaria by distributing
bed nets to help protect people from mosquito bites as they sleep.
Scientists around the world are working to develop a vaccine to
prevent malaria.

3. Epidemiology
 Malaria is presently endemic in a broad band around the equator, in areas
of the Americas, many parts of Asia, and much of Africa; in Sub-Saharan
Africa, 85–90% of malaria fatalities occur.
 The WHO estimates that in 2010 there were 219 million cases of malaria
resulting in 660,000 deaths. Others have estimated the number of cases at
between 350 and 550 million for falciparum malaria and deaths in 2010 at
1.24 million up from 1.0 million deaths in 1990. The majority of cases
(65%) occur in children under 15 years old. About 125 million pregnant
women are at risk of infection each year; in Sub-Saharan Africa, maternal
malaria is associated with up to 200,000 estimated infant deaths yearly.
There are about 10,000 malaria cases per year in Western Europe, and
1300–1500 in the United States.

5. Causes
 Malaria parasites belong to the
genus Plasmodium (phylum Apicomplexa). In humans, malaria is caused
by P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi. Among
those infected, P. falciparum is the most common species identified
(~75%) followed by P. vivax (~20%). Although P. falciparum traditionally
accounts for the majority of deaths. P. vivax proportionally is more
common outside Africa. There have been documented human infections
with several species of Plasmodium from higher apes.

6. Life Cycle
 In the life cycle of Plasmodium, a female Anopheles mosquito (the
definitive host) transmits a motile infective form (called the sporozoite)
to a vertebrate host such as a human (the secondary host), thus acting
as a transmission vector. A sporozoite travels through the blood
vessels to liver cells (hepatocytes), where it reproduces asexually (tissue
schizogony), producing thousands of merozoites. These infect new red
blood cells and initiate a series of asexual multiplication cycles (blood
schizogony) that produce 8 to 24 new infective merozoites, at which
point the cells burst and the infective cycle begins anew.

7. Other merozoites develop into immature gametocytes, which are the
precursors of male and female gametes. When a fertilised mosquito bites an
infected person, gametocytes are taken up with the blood and mature in the
mosquito gut. The male and female gametocytes fuse and form
an ookinete—a fertilized, motile zygote. Ookinetes develop into new
sporozoites that migrate to the insect's salivary glands, ready to infect a new
vertebrate host. The sporozoites are injected into the skin, in the saliva,
when the mosquito takes a subsequent blood meal.

9. Symptoms
 A malaria infection is generally characterized by recurrent attacks with
the following signs and symptoms:
 Moderate to severe shaking chills
 High fever
 Sweating
Other signs and symptoms may include:
 Headache
 Vomiting
 Diarrhea

10. Complications
 In most cases, malaria deaths are related to one or more serious
complications, including:
 Cerebral malaria. If parasite-filled blood cells block small blood vessels to
your brain (cerebral malaria), swelling of your brain or brain damage may
occur. Cerebral malaria may cause coma.
 Breathing problems. Accumulated fluid in your lungs (pulmonary edema)
can make it difficult to breathe.
 Organ failure. Malaria can cause your kidneys or liver to fail, or your
spleen to rupture. Any of these conditions can be life-threatening.
 Anemia. Malaria damages red blood cells, which can result in anemia.
 Low blood sugar. Severe forms of malaria itself can cause low blood
sugar, as can quinine — one of the most common medications used to
combat malaria. Very low blood sugar can result in coma or death.

11. Diagnosis
Although antibody-based diagnostic tests are being used with increasing
frequency, demonstration of asexual forms of the parasite on
peripheralblood smears is required for diagnosis.
• Thick and thin smears should be examined; thick smears and the less
sensitive thin smears detect parasitemia levels as low as 0.001% and
~0.05%, respectively.
• If the level of clinical suspicion is high and smears are initially negative,
they should be repeated q12–24h for 2 days.
• Other laboratory findings generally include normochromic, normocytic
anemia; elevated inflammatory markers; and thrombocytopenia (~105/μL).

13. Treatment
Sensitive P. falciparum malaria:
Artesunatec (4 mg/kg qd for 3 days) plus sulfadoxine (25
mg/kg)/pyrimethamine (1.25 mg/kg) as a single dose.
or
Known chloroquine-sensitive strains of Plasmodium vivax, P. malariae, P.
ovale, P. knowlesi, P. falciparum:
Chloroquine (10 mg of base/kg stat followed by 5 mg/kg at 12, 24, and 36
h or by 10 mg/kg at 24 h and 5 mg/kg at 48 h).
Multidrug-resistant P. falciparum malaria:
Artesunatec (4 mg/kg qd for 3 days) plus Mefloquine (25 mg of base/kg—
either 8 mg/kg qd for 3 days or 15 mg/kg on day 2 and then 10 mg/kg on
day 3).

14. Prevention
 Use flying-insect spray indoors around sleeping areas.
 Avoid areas where malaria and mosquitoes are present if you are at
higher risk.
 Wear protective clothing (long pants and long-sleeved shirts).
 Use insect repellent with DEET (N,N diethylmetatoluamide).
 Use bed nets (mosquito netting) sprayed with or soaked in an
insecticide such as permethrin or deltamethrin.

15. Thank You