Introduction

Classification

Taxonomy

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

Active Forms

Resting Forms

Clinical Effects

Epidemiology

Habitat

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

Lifecycle

• L. setosus lifecycle 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

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.