Antiparasitic agents

Question 1

Parasites contain two main groups,

protozoa (blood, tissue, intestine, genital)
and
metazoa (worms)

name the worms

Answer 1

nematodes (roundworms) - intestinal and tissue

cestodes (tapeworms)

trematodes (flukes)

Question 2

Name the four main species of malaria

Answer 2

plasmodium falciparum

benign
P.vivax
P.ovale
P.malariae

Question 3

Combination therapy is used for malaria, when severe it is IV.

List the treatment for P.falciparum
and
the benign species

Answer 3

P.falciparum 
Artemisinin derivatives (lumefantrine, amodiaquine)
AND
Quinine (doxycycline or clindamycin) 
AND
Atovaquone and Proguanil 

For benign
Chloroquine and Primaquine

Question 4

What is the mechanism of action of chloroquine

Answer 4

Hb ingested by parasite is broken up into globin and haem

free haem is toxic to plasmodium, so polymerises haem to non-toxic haemozoin

chloroquine inhibits the latterm thus plasodium is killed by free haem

Question 5

What is p.falciparum resistant to

Answer 5

chloroquine

Question 6

Phrophylaxis is recommened, what is given in high risk areas and moderate risk areas

Answer 6

high risk - mefloquine, malarone, doxycycline

moderate risk - chloroquine and proguanil

Question 7

African trypanosomiasis?

Answer 7

Tsetse fly vector, cattles

CNS invasion causing sleeping sickness

Question 8

S.American trypansomiasis

Answer 8

Cause Chagas disease through reduviid bug

get Romana’s sign, smooth muscle damage

treat with oral benznidazole and nifurtimox

Question 9

Leishmaniasis

Answer 9

Caused by sandfly

IV AmB
oral Miltefosine

Question 10

Toxoplasmosis differs in immunocompetent and immunocompromised patients

Answer 10

immunocompetent - settles without treatment, lymphadenopathy, glandular fever like illness

immunocompromised e.g. HIV

• brain abscess
• pyrimethamine, sulphadiazine, folinic acid

Question 11

Luminal protozoa, what should you give?

Answer 11

metronidazole

co-trimoxazole
nitazoxanide

Question 12

Intestinal nematodes like ringworm, whipworm are treated by

Answer 12

Mebendazole

Question 13

What is strongyloides capable of and what is it treated with

Answer 13

capable of long term infection, hyperinfection in immunocompromised, and death from gram negative sepsis

ivermectin

Question 14

Onchocersiasis is transferred by blackflies what can cause and what is it treated by

Answer 14

river blindness, fever, itch, oedema, arthritis

ivermectin

Question 15

What are cestodes (tapeworms) likely to transfer from?

Answer 15

beef or pork products

Question 16

What is schistosomiasis treated with

Answer 16

praziquantel and chemo