Malarial parasite:- Part 5 – Plasmodium ovale, Benign Tertian Malaria updated: May 28, 2023, by kamlesh kumar

 

Malarial parasite:- Part 5 – Plasmodium ovale, Benign Tertian Malaria

updated: May 28, 2023, by kamlesh kumar

Plasmodium Ovale

Sample for Plasmodium ovale

1. Malarial parasites (MP) may be diagnosed with a fever from a patient’s blood smear.
   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.

Indication for Plasmodium ovale

• For the diagnosis of the malarial parasite.

Definition of Plasmodium Ovale

1. Plasmodium ovale leads to benign tertian malaria and causes fever for 48 hours.
2. It infects young RBCs, and these have fimbriated cytoplasm.
3. Untreated cases may have relapses for up to 5 years.

Plasmodium ovale life history

1. 8% of cases are in parts of Africa.
   1. Few cases in Asia.
2. Plasmodium ovale represents only a small percentage of infections.
3. Plasmodium ovale has a dormant stage in the liver, which can become active without a mosquito bite.

The erythrocytic cycle of Plasmodium ovale

1. Ring form is like P. vivax.
   1. The difference is that there is a ring larger than the P. vivax.
   2. The ring is also thicker.
2. Trophozoites maintain their ring form.
   1. The amoeboid tendency is common.

MP in trophozoite-form

3. Schizonts consist of dividing chromatin surrounded by the cytoplasm.
   1. There are Rossetts of merozoites, 8 on average.
   2. 3/4 of the cell is occupied by the parasite.

The erythrocytic cycle of the malarial parasite

Clinical presentation of Plasmodium ovale

1. Initial symptoms are flu-like.
2. The typical paroxysm is every 48 hours.
3. Relapse may take place, and there is spontaneous recovery.
4. The above feature is not seen in the P. vivax.

Diagnosis of Plasmodium ovale

1. History of the patient in suspected areas.
2. Blood smear:
   1. Make a blood smear when the patient has a fever. Thin and Thick smears are made.
   2. A thick smear is more helpful in finding M.Parasites.
      1. A thin smear is good for identifying the type of malarial parasite.
   3. Collect blood 6 to 8 hourly till 48 hours to declare negative for malaria.
   4. Giemsa stain is the best choice.
3. Serologic methods are based on immunochromatic techniques. Tests often use a dipstick or cassette format and provide results in 2-15 minutes.
4. Polymerase chain reaction (PCR): Parasite nucleic acids are detected using the PCR technique.
   1.  This is more sensitive than smear microscopy.
   2. This is of limited value for diagnosing acutely ill patients because of the time needed for this procedure.

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 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 of Plasmodium ovale:

1.  Antimalarial drugs are quinidine, chloroquine, primaquine, pyrimethamine, sulfadoxine, mefloquine, tetracyclines, and proguanil.
2. Chloroquine is the drug of choice and is 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. In some areas, Amodiaquine is less toxic, cheap, and effective against chloroquine-resistant P. falciparum.
4. Mefloquine is effective against choloquin resistant P. falciparum.
5. Quinine and quinidine are still the first lines of therapy against P. falciparum.
6. Primaquine is a synthetic drug and is the drug of choice for eradicating the 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.