Parasites Flashcards
Giardia lambia treatment
exam question
Metronidazole or other azole
Toxoplasma gondii treatment
Spiromycin or Pyrimethamine/Sulfadiazine
Schistosomes treatment
Praziquantel
Filariasis treatment
- Ivermectin
2. Diethylcarbamazine
Babesia microti treatment
- Clindamycin + quinone
2. Atovaquone + azithromycin
Cestodes/trematodes treatment
Praziquantel
Albendazole, etc
Nematodes treatment
- Albendazole
- Pyrantel pamoate
- Ivermectin
- Diethylcarbamazine
95% of malaria deaths are due to _____
P. falciparum
Calling card of malaria
Flu-like symptoms
Cyclic high fever/chills/rigors every 48-72 hours
Which Plasmodium sp. is most prevalent?
P. vivax
What is significant about P. vivax and P. ovale?
Contain a latent form of the parasite found in the liver, which can cause relapse. Require additional treatment with Primaquine.
Cardiomegaly occurs in 1/3 of patients affected with which parasite?
Trypanosoma cruzi
What animal is the most likely source of Trichinella infection to humans in the U.S.?
Bear
What is a definitive host?
The host in which the mature or sexually mature parasite lives
What is an intermediate host?
The organism in which the parasite develops
What is a trophozoite?
Metabolically active, usually motile stage. Replication.
What is a cyst?
Non-motile form of parasite, protected by a membrane. Infective stage.
What is a vector?
A living carrier that transports the parasite from infected to non-infected host.
How do protozoa reproduce?
Budding, schizogony, sexually
What is schizogony?
Multiple divisions of the nucleus before cell division
What is significant about Entamoeba histolytica?
It is an invasive organism.
Entamoeba histolytica is transmitted by ______, but not by ______.
Contaminated water / undercooked meat
Structural significance of Entamoeba histolytica cyst
4 nuclei
Thick wall
Calling card of Entamoeba histolytica
Inflammation – deep and then lateral, causing “tear-drop, flask-shaped” ulcers
Major clinical manifestations of Entamoeba histolytica
Watery stools containing mucus and blood
Ulcers
Hepatic infection/abscess
Giardia lamblia reservoir
Humans and animals
Giardia lamblia associated with what conditions?
Crowded conditions–prisons, daycares, etc
Giardia lamblia transmission
Fecal-oral / contaminated water
Giardia lamblia trophozoite structure
exam question
2 prominent nuclei
Ventral sucking disk
4 pairs of flagella
Pear-shaped
Which parasite is highly resistant to chlorine, and is therefore associated with swimming pools?
Cryptosporidium parvum
Clinical manifestations of Cryptosporidium parvum in immunocompromised patients
Horrific diarrhea – 50+ stools per day
Dehydration
This can last for months or years.
Which parasite commonly infects AIDS patients?
Cryptosporidium parvum
Treatment for Cryptosporidium parvum
No effective therapy
Azithromycin may be used (hit or miss)
Which parasite is commonly lethal to AIDS patients?
Cryptosporidium parvum
What is significant about Cryptosporidium parvum?
Its oocytes are acid fast
Used to confirm presence in feces
What is a kinetoplast?
The DNA-containing mitochondria of Trypanosoma
How is Trypanosoma cruzi transmitted?
Reduviid bug – kissing bug
What does Trypanosoma cruzi cause?
Chagas disease
How do you become infected by Trypanosoma cruzi?
Kissing bug lands on you, bites and poops on you. You scratch the bite and rub the feces into the wound. This causes inflammation at the site of infection –> Chagoma.
What is Romana’s sign and what does it signal?
Painless periorbital swelling. Chagas disease caused by Trypanosoma cruzi.
Common chronic implication of Trypanosoma cruzi
exam question
Dilated cardiomyopathy
Trypanosoma cruzi treatment
YNTKT
Nifurtimox
How is Trypanosoma brucei transmitted?
Bite by TseTse Fly
What is the calling card of Trypanosoma brucei?
Winterbottom’s sign –> Enlargement of cervical lymph
Somnolence
Trypanosoma brucei treatment
Suramin
Pentimidine
Leishmania vector
YNTKT
Sandfly
Leishmania treatment
YNTKT
Sodium stibogluconate
Pentamidine
Calling card of Leishmania
Disfiguring, ulcerative lesions with necrotic tissue in the middle
Cestode characteristics
Segmented (YNTKT)
No body cavity or digestive tube
Hermaphroditic
Oral sucker, botridias, double hooks
Trematode characteristics
Unsegmented No body cavity Digestive tube ends in cecum Hermaphroditic (except Schistoma) Oral and ventral suckers
Nematode characteristics
Cylindrical Body cavity Digestive tube ends in anus Dioecious Lips, teeth, filariform extremities, dentary plates
What are the Cestodes?
Taenia and other tapeworms
What is a scolex?
Head of a cestode
Taenia solium structure
YNTKT
Scolex with 4 suckers and a circle of hooklets
Which parasitic infection can lead to megaloblastic anemia?
Diphyllobothrium latum (cestode)
What is the most common tapeworm in the U.S.?
Hymenolepsis nana –> only human tapeworm to complete its cycle in one host
How is Hymenolepsis nana different from other cestodes?
Both larval and adult forms may be found in man
Clinical manifestations of Ancylostoma duodenale (hookworm)
Pot belly
Pica
Finger clubbing
Black stool
Ancylostoma duodenale transmission
YNTKT
Larvae can penetrate skin –> associated with walking barefoot
NOT INGESTED
Parasitic infection caused by walking/running barefoot
Hookworm (Ancylostoma duodenale)
Calling card of Enterobius vermicularis infection
Perianal itching
What does Trichuris trichiura cause?
Prolapsed rectum in severe cases
How is Oncocera volvulus transmitted?
Black fly
Oncocera volvulus treatment
YNTKT
Ivermectin
Colloquial name for Dracunculus medinensis
Guinea Fire Worm Disease
What is the intermediate host for all trematodes?
YNTKT
Snails
What is the infective stage of flukes?
Metacercariae
