Plasmodium falciparum

Plasmodium falciparum

Plasmodium falciparum is highly dangerous because in falciparum malaria parasite multiplies rapidly and results in edema in brain (meningitis), lungs, and blockage of kidney activities.

Black water fever

Plasmodium falciparum is also called black water fever which includes;

Uremia, renal failure, circulatory failure, liver failure, anaemia, pigment calculi, biliary tract infection.

Source and Modes of Transmission

1. Transmitted by female Anopheles mosquito bite

2. Transfusion of malarial blood 

3. Congenital malaria

4. Use of contaminated syringes as in direct addict.

Pathogenesis and clinical manifestations 

Symptoms of malaria occurs 10 to 16 days after infection by mosquitoes.

Symptoms include; 

Bed shaking chills

High fever sweating

Headache muscular pain

Spleen become enlarge and anemia develops.

Life cycle

Plasmodium species complete their life cycle in two hosts;

1. In human; Asexual reproduction take place in human host in liver cell as well as red blood cells.

2. In mosquito; sexual reproduction takes place in mosquito.

1. Human cycle

Sporozoite is infective form of malarial parasite.

These sporozoites are present in salivary gland of female Anopheles mosquitoes.

Man gets infection by bite of Infected mosquito and enter blood circulation.

Through blood parasite, they enter in liver cell humans where they multiply asexually called schizogony.

Thus human cycle starts following stages;

1. Pre- erythrocytic schizogony

Under developing phase inside liver cells.

2. Erythrocytic schizogony

Penetrates red blood cell.

3. Gametogony

Develop in red blood cells, these are sexual forms.

4. Exo- erythrocytic schizogony

Produce merozoites (motile stage of parasite life cycle, release from host red blood cell for destroyed or invade cells.

Merozoites attack red blood cells.

2. Mosquito cycle

Sexual cycle of malaria parasite actually starts in human host by formation of gametocytes which are then transferred to mosquitos for further development.

The gametocytes convert into gametes in mosquito stomach.

Flagellated male gametes (sperm) fuse with female gamete (ova) and produce zygote.

Zygotes form oocysts.

By asexual multiplication of oocysts, many sporozoites are formed which then enter mosquito salivary glands.

From these, they are injected by mosquitoes bite into another human victim to begin cycle again.

1. Sporozoite enter in man

2. Sporozoite enter in human blood /and enter in liver.

3. In liver (exo erythrocytic cycle) sporozoites convert into merozoites.

4. In blood (erythrocytic cycle) merozoites convert into trophozoites.

5. Trophozoites multiply in RBCs and producing new merozoites.

6. Release of merozoites when RBCs repture and can infect other red blood cells.

7. In blood some merozoites become gametocytes.

a. Macrogametocyte female 

b. Microgametocyte male

8. Female mosquito pickup gametocytes from human by sucking blood (sexual cycle of parasite mosquito).

9. In mosquito Macrogametocyte changes into Macrogamete (ova) and microgametocyte changes into microgamete (sperm).

10. Fertilization occurs by fusion ova and sperm, zygote formation occurs.

11. Cyst formed around the zygote called oocyst.

12. Oocyst contain sporozoites.

13. Sporozoites enter salivary gland of mosquito.

14. Bite of mosquitoes infective mosquito Saliva.

Laboratory Diagnosis

Specimen collection

Thick blood smear stained with giema stain provide more amount of RBC and parasite.

Peripheral blood film examination

Microscopic examination of peripheral blood smear is most important diagnostic procedure in malaria.

a. Thick blood film

A large drop of blood taken on center of slide and with help of needle or slide corner spread drop of blood over 1/2 inch square area then, air dry it.

b. Thin blood film

Take drop of blood at one edge of glass slide and spread drop of blood by another glass slide quickly.

So, smear should be smooth and tongue shape.

Staining of thick and thin blood films

Thin smear describes morphology of blood cell and thick smear used for detecting malarial parasites.

Microgametocyte (male) and Macrogametocyte (female) can be seen.

Serological test

IHA and ELISA test used for diagnosis of malaria.

Treatment

Chloroquine is used for treatment of acute malaria. Resistance of this drug in P. Falciparum is reported widely.

Mefloquine is active against chloroquine resistant strains.

Prevention

Mosquito repellents and nets

Spray of chemical

Proper treatment of malarial patient

Biological control by rising of gambushia fish (mosquito fish).

Erythrocytic stage of different species of P. plasmodium