Nematodes: Tissue and Filarial Nematodes

Question 1

Life cycle: larvae- intestine- muscles
Route of infection: ingestion raw or undercooked pork or other infected meat (bear, cougar, wild-boar, walrus) wild pigs in Oklahoma
Geography: worldwide
Specimen source: muscle biopsy
Lab test: muscle biopsy, EIA, bentonite flocculation test, IFAT (immunofluorescent) ELISA - pigs
Pathology: diarrhea, nausea, abdominal pain, general malaise. muscle invasion - periorbital edema. myocarditis, death

Answer 1

Trichinella spiralis

Question 2

Life cycle: eggs-larvae-tissue migration
Route of infection: infective eggs: dog or cat feces
Geography: worldwide
Specimen source: tissue sample
Morphology: 0.5 mm by 20 mcm
Lab test: ELISA- serological tests
Pathology: visceral larva migrans. ocular larva migrans, eosinophilia, fever

Answer 2

Toxocara canis

Toxocara cati

Question 3

Life cycle: larvae-duodenal mucosa- connective tissue
Route of infection: ingesting infected copepods (water fleas)
Geography: Sudan, Ghana, Nigeria
Specimen source: subcutaneous tissue
Morphology: female, 1 meter in length. male, 2 cm
Pathology: erythema, blister formation

Answer 3

Dracunculus medinensis

Question 4

Life cycle: lymphatics-adults; blood-larvae/microfilariae
Route of infection: Culex - night feeder, Aedes - day feeder, Anopheles (Anopheline) - day or night feeder
Geography: Africa - Culex; Pacific-Aedes, Anopheles
Specimen source: blood sample
Morphology: microfilariae size 244-296 mcm
Lab tests: Knott technique (1 ml blood + 10 ml formalin and centrifuge), thick and thin preps, take blood samples 10 PM - 4AM if Africa - H+E, thick: Giemsa, thin: Wright-Giemsa
Pathology: high fever, lymphangitis, lymphadenitis, eosinophilia. chronic infection - elephntiasis

Answer 4

Wuchereria bancrofti

Question 5

Life cycle: larvae-lymphatics-adults
Route of infection: Mansonia-night feeder, Anopheles-day or night feeder
Geography: Far East, Malaysia, India, Vietnam/B. timori-Indonesia, Timor islands
Specimen source: blood sample
Lab tests: Knott conc (1 ml blood + 10 mL formalin and centrifuge), thick and thin preps, take blood samples 10PM - 4AM
Pathology: asymptomatic, chronic condition - elephantiasis

Answer 5

Brugia malayi/ Brugia timori

Question 6

Life cycle: larvae-adults-skin-microfilariae
Route of infection: Chrysops sep. - mango flies or deer flies (LCD mnemonic)
Geography: Africa
Specimen source: blood sample
Lab tests: clinical history. Knott tech (1 mL blood + 10 mL formalin and centrifuge), thick and thin films- day
Pathology: calabar swelling, eosinophilia

Answer 6

Loa loa - African Eyeworm

Question 7

Life cycle: larvae-adults-subcutaneous tissue
Route of infection: Simulium spp, Blackfly or buffalo gnat (SBB mnemonic)
Geography: Africa, Mexico, Central America, S.A.
Specimen source: skin snips
Lab tests: multiple skin snips
Pathology; itchy nodules, may cause blindness

Answer 7

Onchocerca volvulus - River Blindness