Malaria Pathology and Treatment Quiz

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Questions and Answers

Which species of Plasmodium can remain in a latent exoerythrocytic form for extended periods?

P.vivax (correct)

P.ovale (correct)

P.falciparum

P.malariae

What is the sequence of development for merozoites once they invade erythrocytes?

Ring forms -> trophozoites -> erythrocytic schizonts (correct)

Erythrocytic schizonts -> trophozoites -> ring forms

Trophozoites -> ring forms -> erythrocytic schizonts

Gametocytes -> trophozoites -> merozoites

How long do P.falciparum and P.malariae remain in the primary exoerythrocytic stage in the liver?

4 weeks (correct)

2 weeks

6 weeks

1 week

What can merozoites develop into after invading erythrocytes?

Gametocytes Signup and view all the answers

During which stage do merozoites undergo sexual reproduction?

Gametocyte stage Signup and view all the answers

What is a characteristic feature of falciparum malaria?

High level of parasitemia Signup and view all the answers

Which type of drug targets the developing or dormant liver forms of malaria?

Tissue schizonticides Signup and view all the answers

What are drugs that act on erythrocytic parasites called?

Blood schizonticides Signup and view all the answers

Which stage of malaria drugs prevent transmission to mosquitoes?

Gametocides Signup and view all the answers

What serious complication is commonly associated with P. falciparum infections?

Extensive hemolysis Signup and view all the answers

Which term best describes the extensive destruction of red blood cells in malaria?

Hemolysis Signup and view all the answers

What is true about radical cure agents for malaria?

No single agent is considered a radical cure Signup and view all the answers

What mode of malaria transmission is referenced involving direct contact?

Congenital transmission Signup and view all the answers

What is the drug of choice for the treatment of asymptomatic intestinal infection caused by E. histolytica?

Metronidazole Signup and view all the answers

Which of the following conditions is NOT treated with Metronidazole?

Asymptomatic intestinal infection Signup and view all the answers

What common adverse effect is associated with Metronidazole?

Metallic taste Signup and view all the answers

Tinidazole is known to be effective for which of the following infections?

Giardiasis Signup and view all the answers

Which of the following treatments is NOT effective against luminal parasites?

Metronidazole Signup and view all the answers

What is the recommended single dose for treating Trichomoniasis with Metronidazole?

2 g Signup and view all the answers

What is a rare but serious adverse effect of Metronidazole?

Encephalopathy Signup and view all the answers

Which of the following side effects is most likely due to Metronidazole?

Vomiting Signup and view all the answers

What is the mechanism of action for primaquine?

Its mechanisms of antimalarial action are unknown. Signup and view all the answers

What is the primary excretion route for mefloquine?

Bile and feces Signup and view all the answers

Which condition is a contraindication for using mefloquine?

History of convulsions Signup and view all the answers

What is the approximate half-life (T1/2) of primaquine?

3-8 hours Signup and view all the answers

Which of the following statements about mefloquine absorption is correct?

It is well absorbed and absorption is increased by food. Signup and view all the answers

What is the recommended administration strategy to minimize mefloquine toxicity?

Administer in two divided doses 6-8 hours apart. Signup and view all the answers

Which statement is true about primaquine's role in treating malaria?

It is the drug of choice for addressing liver forms of P. vivax and P. ovale. Signup and view all the answers

What is the correct volume of distribution (Vd) for mefloquine?

20 L/kg Signup and view all the answers

What is the primary mechanism of action of albendazole?

Inhibiting microtubule synthesis Signup and view all the answers

Which of the following infections is albendazole NOT effective against?

Cysticercosis Signup and view all the answers

What effect does a high-fat meal have on the absorption of albendazole?

Increases absorption up to 5 times Signup and view all the answers

What is the half-life (T1/2) of albendazole?

8-12 hours Signup and view all the answers

Which of the following drugs would likely decrease the effectiveness of albendazole?

Ritonavir Signup and view all the answers

What is the distribution of albendazole following administration?

In urine, bile, liver, and cyst fluid Signup and view all the answers

Albendazole excretion primarily occurs through which route?

Renal as albendazole sulfoxide Signup and view all the answers

What is the main clinical use of praziquantel?

Effective against schistosomiasis Signup and view all the answers

What is a common adverse reaction to praziquantel?

Nausea Signup and view all the answers

What effect does food have on the absorption of praziquantel?

Increases absorption with high-carbohydrate meals Signup and view all the answers

Which of the following populations is safety established for praziquantel?

Children older than 2 years Signup and view all the answers

What is a major contraindication for the use of praziquantel?

Ocular cysticercosis Signup and view all the answers

What is the typical bioavailability of praziquantel?

80% Signup and view all the answers

What is the maximum plasma concentration time (Tmax) for praziquantel?

1-2 hr Signup and view all the answers

Which of the following conditions is praziquantel mainly used to treat?

Schistosomiasis Signup and view all the answers

Which of the following is a possible mild adverse reaction to praziquantel?

Lassitude Signup and view all the answers

Study Notes

Pharmacology of Antiparasitic Agents and Parasite Diseases

The presentation covers the pharmacology of antiparasitic agents and parasite diseases.
It includes a discussion of antiprotozoal drugs, antimalarial drugs, drugs for treating amebiasis, and anthelmintic drugs.

Introduction of Malaria

Malaria is caused by the Plasmodium protozoan.
The Anopheles mosquito transmits the disease.
It infects approximately 300-500 million people annually.
About 2000 people die each day.
Malaria prevalence has risen in many tropical regions.
It is a threat to non-endemic countries and travelers.

Epidemiology

The geographic distribution of Plasmodium species is not fully documented.
Plasmodium vivax is more prevalent in India, Pakistan, Bangladesh, Sri Lanka, and Central America.
Plasmodium falciparum is prevalent in Africa, Haiti, Dominican Republic, the Amazon region of South America, and New Guinea.
Plasmodium ovale is found in Africa.
Plasmodium malariae is found worldwide.
In the United States, most malaria cases are in immigrants from endemic areas and travelers.
Thailand has P. vivax at 56.8% and P. falciparum at 42.5%.

Life Cycle

The life cycle involves a mosquito vector.
Mosquito injects sporozoites into human host.
Asexual multiplication occurs in the liver.
Merozoites invade red blood cells and replicate.
Gametocytes are formed and enter the mosquito.

Primary Attack & Relapse

A bite from an infected mosquito initiates the primary attack.
Infection with P. vivax and P. ovale can cause relapses.

Antibodies & Immunity

Antibodies to sporozoites block liver invasion.
CD4+ and CD8+ T cells kill intrahepatic parasites.
Antibodies block merozoite invasion of red blood cells.
Antibody-dependent cytotoxicity kills intraerythrocytic parasites.
Antibodies block parasite development and invasion.

Stages of Malaria in Liver & Blood

P. falciparum and P. malariae remain in primary exoerythrocytic stage in the liver for up to 4 weeks.
P. vivax and P. ovale can exist in the liver during latent stages, therefore, infected people may experience relapse.
Merozoites invade erythrocytes and transform into ring forms, trophozoites, and erythrocytic schizonts.
P. falciparum* has high parasitemia, causing more severe infections.

Drugs for Malaria Treatment

Drugs that eliminate developing or dormant liver forms are called tissue schizonticides.
Drugs that target erythrocytic parasites are blood schizonticides.
Drugs that kill sexual stages and prevent transmission to mosquitoes are gametocides.
No single agent provides a complete cure.

Pathology

Malaria's erythrocytic phase causes hemolysis and splenomegaly.
Most serious complications are associated with P. falciparum.
Infants and children under 5, as well as pregnant women without immunity, are at high risk for severe complications.
High parasitemia and sequestration in capillaries and postcapillary vessels of organs like the brain and kidney lead to organ damage and potentially fatal outcomes.

Characteristics of Malaria Parasites

The presentation provides a table comparing the characteristics of P. falciparum, P. vivax, P. ovale, and P. malariae.

Clinical Presentation of Malaria

The clinical presentation may include nonspecific symptoms like fever, chills, and sweating.
More severe symptoms such as severe anemia, high parasitemia, and neurological complications might occur.

Classification of Antimalarial Drugs

The table categorizes antimalarial drugs by their action on different stages of the parasite.

Treatment of Malaria

Treatments vary based on Plasmodium species, patient factors, and resistance patterns.

Chloroquine

Used for susceptible P. falciparum and P. malariae infections.
Inhibits Plasmodium polymerization of heme.
Resistance is common.

Piperaquine

A treatment option for chloroquine-resistant cases.
Effective as part of a combination therapy.
Exhibits resistance, hence combination therapies are now common, particularly in malaria-endemic areas and with multidrug resistance.

Artemisinin & Derivatives

Artemisinin is a sesquiterpene derivative with rapid antimalarial activity.
Effective against blood schizonts, but not mature gametocytes.
Effective in the treatment of severe malaria.
Analogues like artesunate, artemether, and dihydroartemisinin are used to effectively improve solubility, and improve administration options for malaria treatment.

Atovaquone

Used as part of combination therapy to prevent the development of resistance.

Amebiasis (Entamoeba histolytica)

It can cause asymptomatic intestinal infection, colitis, severe intestinal infection (dysentery), ameboma, and liver abscess.

Metronidazole

A treatment of choice for amebiasis.
Effective against luminal parasites, but has limited effect on hepatic stages.

Anthelminthic Drugs

Albendazole, Mebendazole, Diethylcarbamazine citrate (DEC), Ivermectin, Niclosamide, Praziquantel, and Pyrantel pamoate are used to treat helminthic infections.
Helminths (worms) cause a range of diseases, infecting billions of people, including intestinal nematodes, as well as flukes and tapeworms

Drugs for Helminthic Infections

This section provides tables listing the drugs of choice and alternative medications for various types of helminth infections (by organ system).

Mefloquine

Strong blood schizonticidal activity against P. falciparum and P. vivax.
Not active against hepatic stages.
Can be used in areas with chloroquine-resistant strains.

Primaquine

Drug of choice for liver forms of P. vivax and P. ovale.
Can eradicate liver hypnozoites and prevent relapses.

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Description

Test your knowledge on malaria, its life cycle, and treatment strategies with this detailed quiz. Explore questions about Plasmodium species, the development of merozoites, and the characteristics of falciparum malaria. Perfect for students studying parasitology or infectious diseases.