Parasites

Question 1

What are the four genera of free-living amoebae that cause human disease?

Answer 1

Naegleria fowleri
Acanthamoeba spp
Balamuthia mandrillaris
Sappinia pedata

Question 2

Which free-living amoeba causes acute, fulminant primary amoebic encephalitis is immunocompetent children and young adults?

Answer 2

Naegleria fowleri

Question 3

Which two free-living amoebae cause granulomatous amoebic encephalitis?

Answer 3

Acanthamoeba spp

Balamuthia mandrillaris

Question 4

Management of Acanthamoeba encephalitis?

Answer 4

Attempt source control with resection of infected tissue (if surgically feasible)

Reduce immunosuppression

Administer combination anti-infective therapy (given most agents are amebostatic)

Question 5

Antimicrobials used to treat Acanthamoeba encephalitis

Answer 5

Miltefosine
Sterol-targeting azaleas (fluconazole, itraconazole, ketoconazole, voriconazole)
Pentamidine isethionate
Bactrim/sulfadiazine
5-fluorocytosine
Amphotericin B
Azithromycin
Rifampin
Metronidazole

Question 6

The three major reasons for “chronic” infectious diarrhea…

Answer 6

Giardia
Cyclospora
Post-infectious irritable bowel

Question 7

A traveler with chronic diarrhea following a trip to Nepal. What is the most likely organism?

Answer 7

Cyclospora is a major problem among travelers to Nepal in the spring or summer; the illness is characteristically protracted and the laboratory must be alerted to consider this agent if it is to be identified. Trimethoprim-sulfamethoxazole is the treatment of choice. Ciprofloxacin is somewhat less effective.

Question 8

Which medication is safe to give for malaria prophylaxis for a pregnant traveller to an area with chloroquine-resistance?

Answer 8

Mefloquine

Mefloquine is not approved by the FDA for use in pregnancy but appears safe in the second and third trimesters of pregnancy and is active against chloroquine -resistant P. falciparum, which is prevalent in sub-Saharan Africa. CNS side effects can be troublesome