Atlas of livestock parasites
digitized collection of microscopical preparations

Atlas of Parasites Contents Information sources Glossary Administration

Parafilaria bovicola

Category:


Species:
Endoparasite


Description:
Untitled document

Parafilaria bovicola

General Description:

White filarial worm in subcutaneous tissue.

Life Cycle:
Not clearly understood. Females penetrate the dermis and the epidermis to lay their eggs in the subcutaneous tissue. Eggs and microfilariae are found in the blood fluids of the skin. Flies ingest the eggs and larvae; further development takes place in the fly intestine. The larvae enter the principal host when the fly feeds on it. Experimental infections by the intraconjunctival route have been successful in establishing P. bovicola infections in cattle.

Location:
Nodules located under the skin of cattle on upper side of the body.

Geographical Distribution:
Asia, Africa, southern Europe.

Effect on Host:

In response to localization of adult worms under the skin, the host surrounds them with a thickening of skin, or nodule, which is likely to break and ooze blood, causing a hemorrhagic dermatitis. Acute lesions have an opaque yellow-green appearance. Edematous areas are intermingled with clearer areas with petechiae in the subcutaneous tissue on the fascia, and in the superficial muscle layers. Chronic lesions have a greenish dirty brown appearance.

Diagnostic Information:

The incidence of nodules (verminous nodules) varies with seasonal changes; larvae may be found in tissue near nodules where adults live.

Control:

Once the insect intermediate host for this parasite has been identified, control measures can be directed against that insect. Ivermectin has been shown to be effective against these parasites.

Significance:

The lesions caused by this parasite affect the quality of meat, especially from affected animals 1 to 2 years of age. An average condemnation of 6 kilograms of good back cuts has been reported.


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