Canis ISSN: 2398-2942

Linognathus setosus

Synonym(s): L. setosus, sucking louse

Contributor(s): Stephen Barr

Introduction

Classification

Taxonomy

  • Order: Pthiraptera.
  • Suborder: Anoplura.
  • Genus: Linognathus.

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Clinical Effects

Epidemiology

Habitat

  • Permanent parasites on the skin of domestic and wild dogs.
  • Highly host-specific for Canidae.

Lifecycle

  • L. setosus lifecycle diagram Lifecycle Linognathus setosus - diagram.
  • 1. Adult.
  • 2. Egg.
  • 3. Nymphs.

Transmission

  • By direct contact when nymphs or adults transfer to the hair of an in-contact dog.
  • Eggs, nymphs or adults that have been knocked off into the environment are probably of little importance compared with dog-to-dog contact.

Pathological effects

  • Rapid movement of lice through coat and the resulting hypersensitivity response (more intense than the chewing louse Trichodectes canis Trichodectes canis ) can cause intense pruritis and self-excoriation.
  • Heavy infection with sucking lice is characterized by infiltration of the dermis with degranulated mast cells and eosinophils, and also mononuclear cells, suggesting both Type I (immediate) and Type IV (delayed) hypersensitivity reactions, both of which are induced by injection of louse antigen into mice or humans.
  • Desensitization after prolonged heavy infection has been described.
  • Ranges from asymptomatic through to dandruff and seborrhea with lesions from self-excoriation.
  • Linognathus setosus suck blood and in heavy infections can induce anemia.

Other Host Effects

  • Feed on blood.

Control

Control via animal

  • Insecticide treatment of dog and in-contact dogs.
  • The egg stage can last 7-14 days so repeat treatment in 14 days is essential for insecticides that have little residual activity.
  • Improve condition of debilitated dogs.

Control via chemotherapies

  • No insecticides have been licensed specifically for use against lice in dogs. The following should be effective:
    • Permethrin.
    • Dichlorvos/fenitrothion.
    • Phosmet.
    • Fipronil.

Control via environment

  • Bedding should be washed (high temperature) or treated with insecticide and kennels vacated for several days.
  • The egg stage can last 7-14 days so repeat treatments are essential for insecticides that have little residual activity.

Diagnosis

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Further Reading

Publications

Refereed papers


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