Introduction to Parasites (Habal) Flashcards
Neurocysticercosis - Taenia solium
This parasite is more common in male homosexuals and poorly sanitized environments, is prevalent in the tropics, and is obtained through fecal-oral transmission.
Entamoeba histolytica
The species of Trypanosoma is found in the Americas, mainly central and South, emphasis on South.
T. cruzi
Echinococcus granulosus
This form of Leishmania is the most common. It causes relatively benign self-healing lesions. What is it and how would you treat it?
Cutaneous Leishmaniasis
Sodium stibogluconate
Ascaris lumbricoides
This parasite is common in tropical countries. It causes infection through ingestion or larval penetration of skin. Diagnosis is of larva in stool. Clinical manifestiations include itching, wheezing (pneumonia), diarrhea, weight loss.
Strongyloides strocrailis
Romana’s sign - T. cruzi
This parasite is found world-wide in lakes, streams, etc. Risk factors for infection via fecal-oral transmission include contact with domestic and wild animals, camping, and places such as prisons, day cares, and mental health institutions.
Giardia lamblia
Ring-enhancing lesions on brain caused by Toxoplasma gondii
This type of parasite can reproduce in high numbers, leading to many organisms that can obstruct parts of the body, leading to clinical manifestations.
Roundworms - nematodes
T. bruci - enlarged lymph node (Winterbottom’s sign)
Found in sub-Saharan Africa and transmitted by the Tse Tse fly, this parasite causes local inflammation at the site of infection, including swollen lymph nodes. It can cross the blood brain barrier, resulting in CNS involvement that manifests in symptoms such as somnolence and confusion. What is the available treatment for this?
T. bruci
Suramin
Taenia saginata
Adult worm appears yellow with dark markings and grow anywhere from 3-15 m in length. Scolex has 2 sucking grooves. Crustaceans eat eggs found in fresh water. Humans eat these crustaceans, ingesting the eggs, which then become larvae, and then adults which can then lay eggs. Definitive hosts are humans and dogs. Transmission is ingestion of raw, undercooked fish.
Diphyllobothrium latum - fish tapeworm
This protozoa of the Apicomplexa superphylum is a zoonotic, opportunistic parasite. Its definitive host is the domestic cat; vertebrates are the intermediate host. Immunocompromised individuals are at a greater risk of infection, as is the fetus if the mother acquires the infection during gestation.
Toxoplasma gondii
Life cycle of this parasite always includes at least one intermediate host that is a snail.
Trematodes
45 y/o immigrant from Mexico presents with hydrocephalus, motor spasms, paraplegia, loss of vision. He has a history of chronic meningitis. X-Ray shows many holes in brain. What’s wrong with him?
Neurocysticercosis - caused by Taenia solium
This parasite causes infection from soil contaminated with human feces. The adult worm inhabits the cecum and large intestine. Light infections are asymptomatic while heavy infetions cause tenesmus, malnutrition, and diarrhea. In severe cases, you may encounter rectal prolapse.
Trichuris trichiura - whipworm
This species of helminths has a segmented plane, is hermaphroditic, and has an oral sucker, botridias, and double Rostellar hooks.
Cestodes
This species of helminths has an unsegmented plane, has a digestive tube that ends in the cecum, is hermaphroditic (except for Schistosoma, which are dioecious), and has both oral and ventral suckers.
Trematodes
Strongyloides strocrailis
This parasite, which is transmitted by the Reduviid kissing bug, is found in rural and poor areas of Central and South America. Upon infection, the parasite invades macrophages, creating a chagoma.
T. cruzi
This parasite is transmitted by the sand fly and reproduces inside macrophages.
Leishmania
What are the 6 species of Leishmania?
L. donovani
L. tropica
L. major
L. aethiopica
L. mexicana
L. brazilliensis
Echinococcus granulosus
This is the most common tapeworm in the US. It is the only human tapeworm to complete its cycle in one host; both larval and adult forms can be found in man. It can be directly transmitted through ingestion of eggs that hatch in the duodenum or indirectly transmitted through ingestion of infected arthropods. What is it and how would you treat it?
Hymenolepsis nana
Praziqantel
This is one of the largest and most common nematodes in the world. Infection is from soil contaminated with human feces and often occurs when parasite eggs are ingested in undercooked meat. Females produce about 200,000 eggs daily, causing the massive amount of worms that can grow and cause bodily obstructions.
Ascaris lumbricoides
This parasite only infects humans. Male and female worms inhabit the colon; female worms migrate to perianal region at night to lay eggs. Diagnosis is made using the scotch tape test. What it this and how would you treat it?
Enterobius vermicularis - pinworm
Albendazole
Hand washing
This single-celled protozoa that uses flagella to move uses humans and animals as a reservoir and leaves cysts, which can survive in water up to 3 months, in their feces. Symptoms include watery, foul smelling diarrhea, nausea, and weight loss. It is often associated with areas of chronic conditions and stagnant or slowly-moving water that has been contaminated by animal feces.
Giardia lamblia
Using a string test, you identify in your patient a parasite that is known for its pear-shaped trophozoite with 2 prominent nuclei, a ventral sucking disk, and 4 pairs of flagella. Its cyst, which is the infective stage, has 4 nuclei and is passed through the stool. What is this parasite, and what treatment would you choose?
Giardia lamblia
Metronidazole
This parasite causes infection via ingestion of raw or undercooked pork. It has a scolex with 4 suckers and a circle of hooklets. Humans can serve as definitive or intermediate hosts.
Pork tapeworm - Taenia solium