Malarial parasite – Part 2 – Plasmodium Falciparum, MP Falciparum, Black Water Fever

Sample

1. Malarial parasite ( MP ) may be diagnosed from a blood smear of a patient with a fever.
   1. The best time to make a smear is during shivering.
   2. Make thick and thin blood smears.
2. Serum needed for a Serological method and for PCR.

P. Falciparum

1. 80-90% of cases in Africa,
   1. 40-50% of cases in western Pacific and SE Asia,
   2. 4-30% in S. Asia, S. America, and the rest of the topics.
2. P. Falciparum is responsible for the majority of malaria deaths globally.
3. This is the most prevalent species in sub-Saharan Africa.
4. This can infect RBC of any age.
   1. Young RBCs are more vulnerable.
   2. RBCs are not usually enlarged or distorted as seen in P. vivax and P. ovale.
   3. As all ages of RBCs are involved, there is a large amount of toxic cellular material and plugging of the capillaries.
5. Only the ring form and the gametocytes are seen in the peripheral blood.

Exoerythrocytic cycle

1. P. falciparum schizont grows in the liver cells.
   1. It is more irregular in shape than the P. vivax with projections extending in all directions by the fifth day.
   2. After rupture, it releases about 30,000 merozoites.
   3. There may be remission of up to one year.
   4. These merozoites can infect any age of the RBCs even reticulocytes, so it gives a very high level of parasitemia.

Erythrocytic cycle

1. Merozoites enter the all aged RBCs and reticulocytes.
2. There is the sequestration of the RBCs in the capillaries of the brain, spleen, and bone marrow.
3. The early ring form trophozoite is the smallest of any Plasmodium type.
4. Schizonts are less symmetrical than any of other forms.
   1. It forms 8 to 32 merozoites and usually 16 in number.
5. The erythrocytic cycle takes 48 hours.
6. There is a high level of parasitemia with more than 65% of the RBCs containing parasites.
   1. The 25% involvement of RBCs is fatal.
7. Only young trophozoites as ring form and the gametocytes are seen in the peripheral blood.

Clinical presentation

1. There may be early flu-like symptoms.
2. This is the most fatal and threatening type than other types.
3. The incubation period is short 7 to 10 days.
4. There are episodes of chills and fever.
   1. There will be nausea and vomiting.
   2. There will be diarrhea.
   3. There are muscle aches and pain.
   4. These symptoms are cyclical 36 to 48 hours.
5. Blackwater fever or malignant tertian malaria:
   1. When this parasite enters the kidney, brain, and liver
   2. Cerebral malaria is only caused by P. falciparum. These patients will have a cerebral sign and symptoms and may go into a coma.
   3. There is marked hemoglobinuria.
6. P. Falciparum when severe gives rise to:
   1. Coma.
   2. Breathing difficulties.
   3. Low blood sugar.
   4. Low hemoglobin leading to anemia.
7. Children are more prone to develop cerebral malaria.
8. Untreated, severe malaria can lead to death.
9. For the diagnosis smear will show banana-shaped parasites.

Complications

1. There may be an acute renal failure.
2. Other possibilities are tubular necrosis, nephrotic syndrome.
3. The brain is involved with plugs formation in the capillaries and causes cerebral malaria.
4. The patient goes into a coma followed by death.
5. There may be pulmonary edema.
6. There is severe anemia.

Diagnosis

1. Make thick and thin blood smears.
   1. Gametocytes are readily identified.
2. Take smear every 6 to 12 hours, for another 48 hours.
3. Advise serological tests.
4. PCR.

Mosquito control

1. Try to eliminate breeding places:
   1. Fill the vacant land and pump out the water.
   2. Remove the junk and water retaining debris.
2. Destroy the larvae:
   1. Clean the drains.
   2. Try to remove algae from the ponds.
   3. Add larva-eating fish to the ponds.
3. Use of the insecticide:
   1. The best example is DDT.
4. Use of mosquito repellent:
   1. Pyrethroid repellent.
   2. N, N- diethyl meta tolbutamide.
5. Use of mosquito nets.
6. Use of clothes to prevent mosquito bites.
7. Train people for malaria prevalence.
8. Train the people for the detection of malaria, treatment, and follow-up
   

   Malarial Parasite sexual and Asexual Cycle

Treatment

1.  Antimalarial drugs used are quinidine, chloroquine, primaquine, pyrimethamine, sulfadoxine, mefloquine, tetracyclines, and proguanil.
2. Chloroquine is the drug of choice and best for P. falciparum.
   1. This is effective for the erythrocytic stage and not for the liver stage.
   2. Must use primaquine to eradicate P. ovale and P. vivax.
   3. there are chloroquine resistant cases of P. falciparum.
3. Amodiaquin, piperaquin and pyronaridine are close to chloroquin.
   1. Amodiaquine is less toxic, cheap, and in some areas effective against chloroquine-resistant P. falciparum.
4. Mefloquine is effective against choloquin resistant P. falciparum.
5. Quinine and quinidine are still the first line of therapy against P.falciparum.
6. Primaquine is a synthetic drug and is the drug of choice for the eradication of liver-stage from P. vivax and P. ovale.
7. Antibiotics and Inhibitors of folate synthesis are slow-acting antimalarial drugs.
8. Halofantrine and Lumefantrine are related to quinine and effective against the erythrocytic stage.
9. Malaria drug-resistant strains are emerging. 

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