Nematodes - Spirurida - Filarioidea
|Setaria equina|| Host: Equids|
Adult: long, slender, 12cm L
LC: Indirect. Mff in bloodstream are ingested by mosquitoes.
SOI: Adults-peritoneal cavity; Mff-blood; Larvae-eye
CS: None unless nervous tissue involved
Dx: Mff in blood smears. Adults in peritoneal cavity.
|Onchocerca cervicalis||Host: Equids|
IH: Culicoides spp.
Adults: Slender, 2-6cm L, lie tightly coiled in tissue nodules
LC: Inoculation of L3 by Culicoides, arrival of parasite in final host results in host rxn.
SOI: Nuchal ligament at withers. Mff in tissue spaces of skin, skin of umbilicus
Path: Fibrous tissue, ligaments, and intermuscular ct
CS: Pruritic dermatitis (aka microfilarial pityriasis, summer mange, equine dhobie itch, and plica polonica)
Dx: Mff recovered in a saline incubation of skin biopsies, open purulent lesions ("fistulous withers")
|Dirofilaria immitis (Heartworm)||Host: Canine, feline, zoonosis|
Adults: long, slender, 20-30cm L
LC: Adults in pulmonary artery, female releases microfilariae in blood, mosquito ingests microfilariae with blood meal, microfilariae develop in mosquito to infective larvae, mosquito bites and transmits infective larvae.
PPP: 7-9mo Adults survives for years, and can be patent for 5-7yr in dogs.
SOI: Pulmonary artery, right ventricle, caudal vena cava
Path: Severe heart and lung disease changes, endarteritis, congestive heart failure, caval syndrome
CS: Dysfunction of lungs, heart, liver, & kidneys, cough, exercise intolerance, dyspnea, abnormal heart and lung sounds, hepatomegaly, syncope, as cities, death, hemoglo binemia, hemoglobinuria.
Dx: radiology, angiography, u/s, serology, antigen tests -- ELISA & immunochromatographic test
Tx: MCLs, prevention
|Acanthocheilonema (Dipetalonema) reconditum|| Host: Canines|
ID: Mff by progressive motion, few relative number, blunt head and buttonhook or curved tail.
LC: Transmitted by fleas and lice.
SOI: In subcutis, mff in blood and lymph
Path: Occasional cutaneous ulceration
Dx: Differentiate between this and D. immitis mff
Tx: Not necessary