equis - Articles
Oxyuriasis
Introduction
- Equine parastic disease causing perineal irritation via a sensitivity reaction.
- Cause: Oxyuris equi Oxyuris equi - the equine pinworm.
- Signs: tail rubbing, hair loss, irritation and restlessness
. - Diagnosis: age, signs, identification ofOxyuriseggs on transparent adhesive tape imprint taken from perineal area (although this is prone to false negatives).
- Treatment: susceptible to all common oral anti-parasiticides.
Presenting signs
- Perineal pruritus.
- Tail rubbing.
- Perineal alopecia.
- Self-excoriation in perineal area.
Geographic incidence
- Worldwide
Age predisposition
- >3-6 months old.
Cost considerations
- Cheap - easily treated with any of the commonly used anti-parasiticides, then control by hygiene when grooming.
- Treatment of inflammation and secondary infection may also be necessary.
Pathogenesis
Etiology
- Oxyuris equithe equine pinworm Oxyuris equi .
Pathophysiology
- Adult female extends through anus to lay eggs along with cement on perineal skin.
- Presence of cement causes pruritus → horse scratches area.
- Ingested eggs develop to adulthood in colon.
- Presence of cement on the perineum causes a local hypersensitivity reaction → inflammation and pruritus -> self excoriation -> alopecia and secondary infection.
- Presence of L4 larvae cause slight mucosal ulcerations.
Timecourse
- Egg develops to infective L3 larvae in 4-5 days, this is ingested, passes into the intestine and develops via L4 larvae to adult in 4-5 months.
Epidemiology
- Lifecycle involves development of adult in large and small colon. Females migrate to anus and lay eggs on perineum. Eggs stick to perineum or pass out in feces onto bedding or fall or are rubbed off onto bedding.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Reinemeyer C R & Nielsen M K (2014) Review of the biology and control of Oxyuris equi. Equine Vet Educ 46 (11), 584-591 Wiley.
- Costa A J et al (1998) Comparative efficacy evaluation of moxidectin gel and ivermectin paste against internal parasites of equines in Brazil. Vet Parasitol 80 (1), 29-36 PubMed.
- Lyons E T et al (1987) Common internal parasites found in the stomach, large intestine and cranial mesenteric artery of thoroughbreds in Kentucky at necropsy (1985-1986). Am J Vet Res 48 (2), 268-273 PubMed.
Other sources of information
- Urqhart G M, Armour J, Duncan J L et al (1988) Veterinary Parasitology.Longmann Scientific & Technical. ISBN 0 5824 0906 3.
- Rose R J & Hodgson D R (1993) Manual of Equine Practice. Saunders. ISBN 0 7216 3739 6.