Bovis ISSN 2398-2993

Pediculosis

Synonym(s): Louse infestation

Contributor(s): Mike Taylor , Andrew Forbes

Introduction

  • Causes: Hematopinus eurysternus, Hematopinus quadripertusus, Linognathus vituli, Solenopotes capillatus (sucking lice), Bovicola (Damalinia) bovis (chewing lice).
  • Signs: light infestations are asymptomatic: heavy infestations cause irritation leading to rubbing, hair loss and disrupted feeding patterns.
  • Diagnosis: heavy lice infestations are typically seen with the naked eye on the neck, head, inner thighs; denser hair inspect any white areas for presence of lice; microscopic examination to confirm species.
  • Treatment: pour-on or spot-on synthetic pyrethroids, such as cypermethrin, deltamethrin or permethrin; or pour-on macrocyclic lactones including ivermectin, doramectin, eprinomectin and moxidectin.
  • Prognosis: light infestations are usually asymptomatic and so treatment not required; heavy infestations generally respond well to treatment. Underlying debilitation or disease if not corrected may worsen the prognosis.

Pathogenesis

Etiology

  • Pediculosis is caused by the presence of either sucking (Hematopinus eurysternus, Hematopinus quadripertusus, Linognathus vituli, Solenopotes capillatus), or chewing lice (Bovicola bovis) Lice: chewing and sucking.

Predisposing factors

General

  • Heavy louse infestation can often be associated with some other underlying condition such as malnutrition or chronic disease.

Specific

  • High stocking densities that enable close physical contact increase transmission of lice between hosts.

Pathophysiology

  • Sucking lice:
    • Feed on host blood using their piercing mouthparts.
    • In severe infestations, the entire region from the base of the horns to the base of the tail can be infested.
    • Linognathus vituli is capable of transmitting bovine anaplasmosis Anaplasmosis, dermatomycosis (ringworm) Ringworm and theileriosis Theileriosis.
  • Chewing lice:
    • Feed on the outer layers of the hair shafts, and skin scales, by scraping scurf and skin debris from the base of the hairs, causing considerable irritation.
    • This can lead to irritation, rubbing or scratching, resulting in patches of hair being pulled or rubbed off.
    • Scratching may produce wounds or bruises leading to secondary skin infections and skin trauma.

Timecourse

  • Populations of lice can build up within a few months in housed cattle during the winter when the coat is thickest.

Epidemiology

  • Lice have specific temperature and humidity requirements on the body of cattle.
  • In temperate seasonal climates, heaviest louse populations are seen in late winter and early spring when the coat is thickest. Lice migrate to those areas that provide the optimal warm and humid environments, which for suckling liec include thinner skinned regions such as the head and neck.

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.
  • Fadok V A (1984) Parasitic skin disease of large animals. Veterinary Clinics of North America, Large Animal Practice 6, 3-26 PubMed.

Other sources of information

  • Taylor M A, Coop R L & Wall R L (2016) Chapter 8 - Parasites of Cattle. In: Veterinary Parasitology. 4th Edition. John Wiley & Sons, Chichester, West Sussex, UK. pp 380-382.
  • Scott P & Taylor M (2013) Internal and External Parasites of Cattle. Zoetis UK Ltd, Walton-on-the Hill, UK. 85 pages.
  • Taylor M A (2004) Bovine Antiparasitics. In: Bovine Medicine, Diseases and Husbandry of Cattle. Blackwell Scientific Publications. 2nd edn. Eds: Andrews A H, Blowey R W, Boyd H, Eddy R G. Chapter 60, pp 1030-1033.
  • Taylor S M, Hunter A G & Williams B M (2004) Ectoparasites, tick and arthropod diseases. In: Bovine Medicine, Diseases and Husbandry of Cattle. Blackwell Scientific Publications. 2nd edn. Eds: Andrews A H, Blowey R W, Boyd H & Eddy R G. Chapter 45, pp 740-778.
  • Taylor M A (2004) Chemotherapeutics of Ectoparasiticides: Large Animals. Merck Veterinary Manual. 9th edn. Merial Whitehouse Station, NJ, USA. pp 2158-2168.


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