Parasites: Helminths - Nematodes Flashcards
Enterobius vermicularis
an intestinal nematode
female Enterobius vermicularis nematodes oviposit their eggs around the
anus
Enterobius vermicularis is transmitted via the
fecal-oral route
the Scotch tape test
the Scotch tape test (application of tape to the anal early in the morning) can confirm presence of Enterobius vermicularis (eggs will be visible upon microscopic examination of tape strip)
treatment of Enterobius vermicularis infection includes
pyrantel pamoate
___________ is effective against the intestinal nematodes: Enterobius vermicularis, Ancylostoma duodenale, Necator americanus, Ascaris lumbricoides, Strongyloides stercoralis and Trichinella spiralis
albendazole
Ancylostoma duodenale and Necator americanus
hookworms (intestinal nematodes)
Ancylostoma duodenale
an intestinal nematode
Necator americanus
an intestinal nematode
Ancylostoma duodenale and Necator americanus are
hookworms
Ancylostoma duodenale and Necator americanus larvae enter the body by
penetrating exposed skin (mostly the feet)
after penetrating the skin, Ancylostoma duodenale and Necator americanus travel
after penetrating the skin, Ancylostoma duodenale and Necator americanus travel from the bloodstream → lungs/trachea → pharynx (where the worms are swallowed) → GI tract
Ancylostoma duodenale and Necator americanus infections may result in
iron deficiency anemia, which is characterized by microcytic, hypochromic RBCs on blood smear
Ancylostoma duodenale and Necator americanus infections are diagnosed by
the presence of eggs in the stool
_____ is seen in Ancylostoma duodenale and Necator americanus infections
eosinophilia
treatment of Ancylostoma duodenale and Necator americanus infections includes
pyrantel pamoate
Ascaris lumbricoides
an intestinal nematode
after ingestion of eggs, Ascaris lumbricoides travels
from the small intestine → bloodstream → lungs/trachea → pharynx (where the worms are swallowed) → GI tract
Ascaris lumbricoides is
the intestinal nematode most highly associated with respiratory symptoms
a major complication of Ascaris lumbricoides infection is
obstruction of the ileocecal valve
Ascaris lumbricoides infection is diagnosed by
the presence of eggs in the stool
______ is seen in Ascaris lumbricoides infection
eosinophilia
Strongyloides stercoralis
an intestinal nematode
Strongyloides stercoralis larvae enter the body by
penetrating exposed skin (mostly the feet)
after penetrating the skin, Strongyloides stercoralis travels
after penetrating the skin, Strongyloides stercoralis travels from the bloodstream → lungs/trachea → pharynx (where the worms are swallowed) → GI tract
Strongyloides stercoralis autoinfection
larvae hatch from eggs laid in the intestinal wall, repenetrate the wall, and enter the bloodstream in Strongyloides stercoralis autoinfection
Strongyloides stercoralis infection is diagnosed by
presence of larvae in the stool
eosinophilia
is seen in Strongyloides stercoralis infection
treatment of Strongyloides stercoralis infection includes
ivermectin
Trichinella spiralis
an intestinal nematode
Trichinella spiralis is found in
undercooked meat (such as pork or bear)
Trichinella spiralis infection can cause
periorbital edema
Trichinella spiralis infection presents with
nausea and vomiting
Trichinella spiralis can cause
fever
Trichinella spiralis larvae are carried to
muscle via the bloodstream
Trichinella spiralis larvae travel to striated muscle
where they form cysts
Trichinella spiralis larvae form
cysts within striated muscle
Trichinella spiralis infection can cause
muscle inflammation and myalgia
_______ is seen in Trichinella spiralis infection
eosinophilia
List the Intestinal Nematodes (Helminths)
- Enterobius Vernicularis
- Ancylostoma Duodenale
- Necator Americanus
- Ascaris Lumbricoides
- Stronglyoides Stercoralis
- Trichinella Spiralis
List the Tissue Nematodes (Helminths)
- Dracunulus Medinensis
- Wuchereria Bancrofti
- Onchocerca Volvulus
- Toxocara Canis
- Loa Loa
Dracunculus medinensis
a tissue nematode
Dracunculus medinensis is transmitted via
water contaminated with copepods containing larvae
copepods (small crustaceans) are intermediate hosts of
Dracunculus medinensis
adult female Dracunculus medinensis nematodes emerge from
painful skin ulcers
Dracunculus medinensis nematodes are removed by
slowly wrapping the worms around a stick
_______ is seen in Dracunculus medinensis infection
eosinophilia
Onchocerca volvulus
a tissue nematode
Onchocerca volvulus microfilariae in the eye can cause
blindness
________ is seen in Onchocerca volvulus infection
eosinophilia
Onchocerca volvulus microfilariae are seen on microscopy of
skin biopsy
________ is effective against Onchocerca volvulus
ivermectin
Wuchereria bancrofti
a tissue nematode
Wuchereria bancrofti causes
lymphatic filariasis (known as elephantiasis, a chronic, severe lymphedema)
Wuchereria bancrofti can cause
lymphangitis and painful lymphadenopathy
lymphangitis and painful lymphadenopathy
tropical pulmonary eosinophilia, characterized by nocturnal cough, wheezing, and dyspnea
________ are the vector of Wuchereria bancrofti
mosquitoes
Wuchereria bancrofti nematodes are seen on
thick blood smear
________ is seen in Wuchereria bancrofti infection
eosinophilia
________ is effective against Wuchereria bancrofti
diethylcarbamazine
Toxocara canis
a tissue nematode
Toxocara canis is transmitted via
food contaminated with infected dog or cat feces
ocular larva migrans
ocular larva migrans (an invasion of the eye by Toxocara canis) can lead to blindness
_______ is seen in Toxocara canis infection
eosinophilia
_______ is effective against Toxocara canis
albendazole
Loa loa
a tissue nematode
migrating Loa loa nematodes can
cause cyst-like collections in subcutaneous tissue (especially near the eye and tendons)
adult Loa loa worms can
migrate across the conjunctiva
Loa loa microfilariae can be
detected on blood smear
______ _____ are the vector of Loa loa
deer flies
_______ is seen in Loa loa infection
eosinophilia
________ is effective against Loa loa
- diethylcarbamazine
2. albendazole