Parasitology Flashcards by Zubia Mahmood

What is a protozoan? Give some examples

Parasite
Unicellular eukaryote
Ex. Malaria, giardia, entamoeba

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What is a helminth? Give some examples

Parasite; “worms”
Multicellular
Ex. Ascaris, loa loa, strongyloides

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Are life cycles the same for all parasites?

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What are the general steps involved in the lifecycle of a parasite?

Enter host
Migrate to target organ
Develop into adult form
Wreak havoc on pts
Spread (release eggs, leave host)

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What are the general diagnostics used in identifying parasites in an infected host?

Serology - while parasite “wrecking havoc”
Microscopy - while parasite “spread”

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How is entamoeba histolytica transmitted?

Fecal/oral route

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What clinical diseases are associated with entamoeba histolytica?

Dysentery
Rare: abscesses in liver, brain, lungs (IC pts)

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What is the treatment for entamoeba histolytica?

Metronidazole + paromycin (for cysts)

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This parasite causes “beaver fever” and it not treated as it is self-limiting

Giardia lamblia/duodenalis

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What clinical diseases are associated with Giardia?

GI distress: loose stools with no blood
Rare: fever, hives

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What are the diagnostic tests used for Giardia?

Identification of trophozoites (adults) or cysts (eggs) in stool
Serology and PCR are also options

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This parasite causes the most severe and dangerous form of malaria

Plasmodium falciparum

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What does plasmodium look like on a blood smear?

A ring structure within an RBC

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How does plasmodium spp. cause anemia?

Grows within an RBC, gets too big —> cell bursting

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What are the treatments for plasmodium?

Malaria is treated with Chloroquine

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What are the post-exposure prophylaxis options for plasmodium?

Atovaquone/proguanil
Doxycycline

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How is plasmodium commonly transmitted to humans?

Via mosquitoes that are carrying the parasite
The mosquitoes acquire the parasite by taking a blood meal from an infected host

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This amoeba is commonly associated with improper contact lens cleaning and can cause eye infection and in rare causes spread to the brain (granulomatous encephalitis)

Acanthamoeba

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One of the diagnostic tests for acanthamoeba is placing it on agar and observing if it causes cell lysis on agar. What organism is lysed on the agar?

E. Coli

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What is the treatment for acanthamoeba?

Miltefosine

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This parasite is transmitted by contaminated cat faces, meat/water, and can be transmitted congenitally.

Toxoplasma gondii

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What is the treatment of toxoplasma?

Usually not treated as it’s self-limiting
May need to be treated in pregnancy with pyrimethamine to prevent spread to infant

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In which trimester is there risk of toxoplasma being transmitted to the fetus?

3rd trimester —> 60-80% likelihood

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Chagas disease is associated with this parasite. It is transmitted by blood, congenitally, or by the kissing bug

Trypanosoma cruzi

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Trypanosoma cruzi is found in what parts of the globe?

The Americas

What are the 2 phases of Chagas disease?

**Acute** flu like, lymphadenopathy. 50% asymptomatic **Chronic** majority (80%) are asymptomatic, cardiac issues (rare) or GI issues

What are the treatment options for trypanosoma cruzi?

Benznidazole Nifurtimox

This pathogen is responsible for causing African sleeping sickness

Trypanosoma brucei

Trypanosoma brucei is responsible for causing African sleeping sickness. What are the stages of this disease?

Stage 1: chancre (painless, firm ulcer), flu-like Stage 2: month/years later —> CNS infection, severe

What are the treatment options for trypanosoma brucei?

Pentamidine

Kala-azar is associted with what pathogen?

Leishmania donovani

What organs does kala-azar impact?

Spleen/liver

What regions of the world is leishmania spp. associated with?

Old world: Asia, Africa New world: Mexico, central/south americas

How is leishmania spp. transmitted?

Sand fly bite Blood Congenital

What 3 ways can clinical disease manifest with leishmania spp?

Cutaneous Visceral Mucosal

What are the visceral manifestations of clinical disease in leishmania?

Non-tender liver/spleen enlargement

What are the treatments for leishmania spp?

Treatment is geared towards preventing secondary infection With kala-azar amphotericin B with heat/cold therapy

Colloquially called “African eye worm”, this helminth is found in West Africa and presents with calabar swelling in severe clinical cases

Loa Loa; round nematode

What is calabar swelling?

Localized, transient angioedema in response to metabolites released by the parasite

How is loa loa transmitted?

Deer fly bite

What is the treatment for loa loa?

Diethylcarbamazine (DEC)

Although this roundworm is asymptomatic in 80% of cases, it is associated with Loeffler’s syndrome and bronchitis if larva migrate through the lungs

Ascaris lumbricoides

What is the treatment for ascaris lumbricoides?

Albendazoel

This is the most common roundworm, presents clinically with mild perianal itching and eosinophilia. It is colloquially called pinworm

Enterobius vermicularis

What is the treatment for enterobius vermicularis?

Albendazole

There are 2 parasites associated with Loeffler’s syndrome. What are they?

- Ascaris lumbricoides - Strongyloides stercoralis

What is loeffler’s syndrome characterized by?

Mild resp symptoms Peripheral blood eosinophilia Transient, migratory pulmonary infiltrates

This threadworm is associated with the clinical disease larva currens (tracks under skin from worm migration) and loeffler’s syndrome

Strongyloides stercoralis

What is the treatment for stronglyloides stercoralis?

Ivermectin

How is strongyloides stercolarlis spread?

Found mainly in the tropics, linked mainly to poor sanitation Penetrates skin from soil

What parasite is colloquially called “pig tapeworm”?

Taenia solium

What are the clinical diseases associated with taenia solium?

Taeniasis - infection with taeniasis; causes GI symptoms, weight loss, and fatigue Cysticercosis - migration of tapeworm to the brain

What is the treatment for Tania solium?

For GI: Praziquantel For Cystercosis: Albenazole

What is the name of the parasite that causes cattle tapeworm?

Taenia saginata

Although both T. solium and T. Saginata are tapeworms, they have a key difference in clinical diseases associated with them

T. Saginata doesn’t cause cysticercosis; T. Solium does

What is the treatment for t. Saginata?

Praziquantel

What clinical diseases are associated with echinococcus spp?

GI discomfort Hydatid disease - happens in severe cases. Oncosphere (egg) makes cysts, goes to lung/liver and causes organ obstruction

What is the treatment for echinococcus spp.?

Surgery for hydatid Albendazole

This parasite is associated with clinical disease such as swimmer’s itch, schistosomiasis, and chronic GI issues

Schistosoma spp.

What is schistosomiasis?

Migration of eggs through tissue

This factor determines which tool is used for the diagnosis of schistosoma spp.

The species determines wether to look for the eggs; S. mansoni and s. japonicum are found in the stool s. Haemotobuim are found in urine only

What is the treatment for schistosoma?

Praziquantel

Are bedbugs associated with any infectious diseases?

Are lice a vector for any infectious diseases?

Yes; typhus and trench fever

This genus of mosquitoes is responsible for the transmission of plasmodium

Plasmodium spp. is responsible for malaria Anaopheles spp. are the main carriers of Plasmodium