Protozoal Infections and Their Treatments

1. What are protozoa?

Protozoa are motile, unicellular eukaryotic organisms that can cause various diseases in humans.

2. How are protozoa generally classified based on their mode of locomotion?

They are classified into four main groups: amoebas, flagellates, sporozoa, and ciliates.

3. What is the causative agent of malaria?

Malaria is caused by parasites belonging to the genus Plasmodium.

4. Name the four main Plasmodium species that infect humans.

Plasmodium vivax, Plasmodium falciparum, Plasmodium ovale, and Plasmodium malariae.

5. Which vector transmits malaria?

Female Anopheles mosquitoes carry and transmit the malaria parasite.

6. What is the pre-erythrocytic stage of the malaria parasite life cycle?

It is the stage where sporozoites travel to the liver and develop into schizonts.

7. What is the erythrocytic cycle in malaria?

Merozoites infect red blood cells, transform into trophozoites, develop, and release new merozoites, causing characteristic fever and symptoms.

8. Which Plasmodium species can cause a relapse of malaria due to dormant hypnozoites in the liver?

Plasmodium vivax and Plasmodium ovale can cause relapses due to dormant hypnozoites in the liver, known as the exoerythrocytic stage.

9. What is the difference between benign tertian malaria and malignant tertian malaria?

P. vivax causes benign tertian malaria, while P. falciparum leads to the more dangerous malignant tertian malaria.

10. What are Artemisinin derivatives primarily used for in malaria treatment?

They are fast-acting blood schizonticidal agents effective against both P. falciparum and P. vivax, often used in combination therapy.

11. What is 'cinchonism' and which antimalarial drug can cause it?

Cinchonism is a syndrome caused by quinine, manifesting with gastrointestinal distress, headache, vertigo, blurred vision, and tinnitus.

12. How does chloroquine exert its antimalarial action?

Chloroquine inhibits haem polymerase, preventing the polymerization of toxic free haem into hemozoin within the parasite.

13. Which category of antimalarial drugs targets hypnozoites in the liver to prevent disease relapse?

Drugs providing a 'radical cure,' such as primaquine and tafenoquine, target liver hypnozoites to prevent relapses.

14. What is amebiasis and which organism is the main concern?

Amebiasis is an infection caused by Entamoeba organisms, with Entamoeba histolytica being the main concern, causing amebic dysentery.

15. What is the drug of choice for acute invasive intestinal amebiasis?

Metronidazole or tinidazole, followed by diloxanide, is used for acute invasive intestinal amebiasis.

16. How do metronidazole and tinidazole kill E. histolytica trophozoites?

They form nitro free radicals that attack DNA and proteins, causing a cytotoxic effect when reduced by pyruvate-ferredoxin oxidoreductase.

17. What is a significant side effect of metronidazole regarding alcohol consumption?

Metronidazole causes a disulfiram-like reaction with ethanol, so alcohol consumption must be avoided during treatment.

18. Which drug is a luminal amebicide but not a tissue amebicide, and can be used for asymptomatic carriers of E. histolytica?

Paromomycin is a luminal amebicide used for asymptomatic carriers, but needs combination therapy for symptomatic disease.

19. What is the causative agent of toxoplasmosis and what are its severe effects in immunocompromised individuals?

Toxoplasmosis is caused by Toxoplasma gondii, which can cause severe damage to organs, including ocular infections and encephalitis, in immunocompromised individuals.

20. What is the treatment of choice for Pneumocystis jiroveci infections?

The treatment of choice for P. jiroveci infections is trimethoprim-sulfamethoxazole.

21. Which protozoal disease is known as sleeping sickness and what is its vector?

African trypanosomiasis, or sleeping sickness, is caused by Trypanosoma brucei and transmitted by the tsetse fly.

22. What is the drug of choice for American trypanosomiasis (Chagas disease)?

Nifurtimox is the drug of choice for the treatment of Chagas disease.

23. What are the three main clinical manifestations of leishmaniasis?

Cutaneous, mucosal, and visceral syndromes are the main clinical manifestations of leishmaniasis.

24. Name two pentavalent antimony compounds used in visceral leishmaniasis treatment.

Sodium stibogluconate and meglumine are pentavalent antimony compounds used for visceral leishmaniasis.

25. What is the mechanism of action of Miltefosine in treating leishmaniasis?

Miltefosine is a membrane-active phospholipid that inhibits enzymes involved in the metabolism of glycolipids found on the surface of Leishmania species.