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Onchocerca spp
Synonym(s): Onchocerciasis, Onchocerca gutturosa, Onchocerca lienalis, Onchocerca gibsoni, Onchocerca armillata, Onchocerca ochengi, Onchocerca dukei, Onchocerca cebei
Introduction
Classification
Taxonomy
- Phylum: Nematoda.
- Class: Secernentea.
- Superfamily: Filariodea.
- Genus: Onchocerca.
- Species: gutturosa (synonym lienalis), armillata, gibsoni, ochengi (synonym dermatata), dukei, cebei (synonym sweetae).
Distribution
- The 6 species are distributed in various regions of the world. Incidence varies regionally and seasonally depending on the abundance of the intermediate host.
- O.gutturosa : Australia, N.Africa and Europe (including the UK).
- O.gibsoni : Australia, Asia, South Africa, North America.
- O.ochengi: East and West Africa.
- O.armillata : Middle East, Africa, India.
- O.dukei : West Africa.
- O.cebei : Far East, Australia.
Significance
- UK - little clinical significance - a study in 1971 showed the incidence of adult O.guttorosa in the nuchal ligament of slaughtered dairy cows was 58%.
- Some economic loss due to carcass trimming or blemished hides.
- O.ochengi is the closest relative to O.volvulus, the causative agent of river blindness in humans. It has been used in comparative field and laboratory studies.
- O.armillata causes typical nodular lesions in the wall of the aorta that can be seen on post mortem examination but is not usually responsible for any clinical signs.
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Clinical Effects
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Diagnosis
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Further Reading
Publications
Refereed Papers
- Recent references from PubMed and VetMedResource.
- Eichler D A & Nelson G S (1971) Studies on Onchocerca gutturosa (Neumann, 1910) and its Developement in Simulium ornatum (Meigen, 1818). I. Observations on O. gutturosa in cattle in South-East England. J Helminthol 45 (2), 245-58 PubMed.
Other sources of information
- Taylor M A, Coop R M & Wall R (2016) Parasites of Cattle. In: Veterinary Parasitology. 4th edn. Wiley-Blackwell Publishing, UK. pp 417-418.