L 67 Trichinosis and Larva Migrans Flashcards
Official word for roundworm
Nematodes
How do you get infected with trichinellosis?
Ingest the eggs or larvae from the environment that mature to adults in the intestines
Ingest raw/undercooked meat with encysted larvae (adult and encysted larvae in same host)
Pig, horse, bear, moose, boar, other mammals
How do you get infected with cutaneous or visceral larva migrans?
Visceral larva migrans: eggs or larvae ingested
Cutaneous larva migrans: larvae penetrate the skin
Infective agent of Trichinellosis
Trichinella spiralis
Where in the body do Trichinella worms go?
We eat muscle from an infected animal and the larvae mature in small intestine. Females give birth and the larvae migrate to the most active muscles in the body and encyst intracellularly where they are viable for months to years.
Clinical manifestations of Trichinellosis
Intestinal phase: nausea, diarrhea, vomiting, abdominal pain; symptoms usually abate 2-5 weeks later
Systemic phase: myalgia, facial swelling, eosinophilia, F/C, weakness, headache, cough, subungual splinter hemorrhages; heavy infections may damage the heart (life threatening), CNS, lungs, kidneys
Trichinellosis diagnosis
Myalgia, periorbital edema, eosinophilia, Hx eating pork, bear, etc.
Serological tests 3-5 weeks into infection
Muscle biopsy definitive but not required
Trichinellosis treatment
DOC: albendazole or mebendazole
Corticosteroids manage inflammation
Trichinellosis control
Careful control of pig farming techniques, meat inspection, keep mice and rats at bay
Cook well pork and other meats
Freezing will only kill in pork meat but not in bear or other meat
Salting/smoking/drying doesn’t work
Larva Migrans primary hosts
These are a zoonotic infection, prefer GI of dogs, cats, and others
Humans are accidental hosts, rarely do they make it into our guts and rearely do they mature to adults
Visceral Larva Migrans infection
Ingestion of the Eggs from the soil
Ingestion of encysted larva from undercooked liver or meat
Cutaneous Larva Migrans
Soil-dwelling larvae penetrate human skin
Causative agents of Visceral Larva Migrans
Toxocara canis and T. cati
Who tends to get infected by visceral Larva Migrans?
Kids who play in soil
The eggs get into the soil from the feces of dogs and cats and other animals, eggs viable 3-4 weeks later. Prefers warm, moist, soil
VLM manifestations
Most infections are asymptomatic
14% of people are infected, but only 100 sever cases per year
Symptoms occur from the damage caused by the migrating larva and the host eosinophilic response
Invades mostly LIVER, LUNGS, but also heart, brain, and muscle
Fever, anorexia, weight loss, cough, wheezing, rashes, H/S-megally
Ocular Larva Migrans (OLM): in retina of the eye causing irreversible vision loss
