Linguatula serrata

Copyright Cooper Curtice (Washington, Government Printing Office, 1890) Wikimedia Commons

• Also known as the tongue worm

• A highly specialised arthropod

Recognition

• Tongue-like appearance
  • Expanded anteriorly

• Adults are over 10cm in length
  • Females measure between 30-130mm in length
  • Males measure up to 20mm in length

• Transversely striated

Life cycle

• Life cycle takes 6 months

• Adults inhabit the nasal passages of dogs and sometimes cats

• Eggs are expelled by coughing and sneezing or are passed out with the faeces

• Herbivorous intermediate hosts ingest the eggs

• Eggs hatch in the herbivore intestine

• Larvae migrate to the mesenteric lymph nodes and encyst to become infective nymphs
  • Cysts measure 1mm in diameter

• When a dog eats infected uncooked viscera the life cycle is completed

• Infective nymphs migrate from the viscera during chewing and crawl up into the nasal cavity via the soft palate

• Infective nymphs mature to adults in the nasal cavities and can survive for a year in the final host

Pathogenesis

• Causes rhinitis

• Heavy infection leads to coughing, sneezing and nasal discharge

• Synonym: tongue worm
• In nasal passages of dogs, sometimes cats
• May reach the sinuses
• Heavy infections may cause sneezing, coughing, nasal discharge