Ruminant Lungworms and Miscellaneous Nematodes

Dictyocaulus

Large size Dictyocaulus in large airways.

Yearling calf with “anoxic syndrome” during prepatent (1-3wk, phase II) of massive lungworm infection.

“Anoxic syndrome”

Initial lungworm infection 1-7 days is not associated with clinical signs.

Lung lobe showing severe intersitial edema inflammation. Lesions and worms are concentrated in diaphragmatic and cardiac lobes.

Pulmonary emphysema, bovine lungworms

Pulmonary emphysema, bovine lungworms

Eosinophilic granulomatous inflammation with eventual alveolar epithelialization.

Histopathological Lesions

Muellerius - alveolar level “blister lesions” of the sheep and goat protostrongylid lungworm transmitted by land snail intermediate host.

Notched tail of Muellerius L1.

Protostrongylus is a related lungworm that resides more toward the terminal bronchioles, with larger infarct-like lesions on the serosal surface.

Stephanofilaria - umbilical lesion

Stephanofilaria - Horn fly as intermediate host.

Stephanofilaria - Histopathological lesions involve eosinophilic granulomatous inflammation.

Muzzle disease due to Eleophora in sheep >5000 feet Rocky mountain ranges shared by deer, the “normal” host.

Eleophora sometimes resides in digital arteries, with similar dermatitis of the lower limb.

Adult filarid Eleophora in carotid arteries; microfilaria, debris as swept up to muzzle skin, resulting in inflammation, necrosis.

Thelazia Infection

Musca autumnalis (face fly) intermediate host of Thelazia lacrimalis in the Eastern U.S. The lesser housefly (Fannia spp) transmits eyeworms in the West.

Thelazia effects

Filarids: Site and Hosts

Setaria microfilariae circulate in peripheral blood to be picked up by mosquito intermediate host.