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LINGUATULA SERRATA - NOSE OR TONGUE WORM

First broadcast on www.provet.co.uk  


This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Linguatula Serrata is a parasitic worm that lives in the nose and sinuses of cats, dog, reptiles, birds and humans. It is uncommon in the UK and USA, but has a prevalence of over 40% in some Middle Eastern countries.


This parasitic worm (a Pentastome) can grow to be 10cm in length. The adult worm lives in the nasal cavities and sinuses and sheds large numbers of eggs which are :

  • swallowed by the cat or dog host and passed out in the faeces , OR
  • sneezed out of the animal

If ingested the eggs that are passed are infective for other species of animal including humans, pigs, horses rabbits, rodents (rats and mice) and ruminants (cattle, sheep, goats). In these species (which act as Intermediate hosts for the parasite) the eggs hatch into larvae, travel to various tissues and form cysts and then develop into "nymphs". 

Description

  • Adults
    • Shape : tongue-shaped worms
    • Legless
    • Body : transversely striated
    • Characteristics : 2 pairs of retractable hooks around the stoma
    • Size : females 8-13 cm long, males 1.8-2 cm long
    • Colour : some are transparent
  • Eggs
    • Shape : oval
    • size : 90 x 70 microns
    • Colour : brownish
    • Contents :  a clawed larva
  • Larvae
    • Size : up to 500 microns
    • Characteristics
      • no mouthparts
      • no striations
      • 2 or 3 pairs of rudimentary clawed legs
  • Nymphs
    • Similar to adults, but lack mature reproductive organs
    • Size : 4-6 mm

The disease is transmitted to other animals including cats, dogs and occasionally humans when these "nymphs" are eaten by a potential host....usually through eating raw or under-cooked offal.

Signs

Usually this parasite causes no signs. In cats and dogs the main clinical signs are:

  • A nasal discharge - may contain blood
  • Sneezing
  • Increased noise during breathing - due to obstruction of the airways by the parasite
  • Listlessness

In humans the main signs are :

  • Difficulty breathing
  • Coughing
  • Difficulty eating
  • Headaches
  • Sometimes infected people develop a skin problem as well
  • Death - rare - due to asphyxia

The human disease is called "Halzoun" in endemic countries.

Diagnosis

Confirmation of the diagnosis is made by :

  • finding eggs/larvae in the nasal discharges or faeces
  • finding nymphs in body tissues of Intermediate hosts

Treatment

  • Surgical removal is sometimes attempted but it is difficult
  • Adults :
    • Levamisole at 5 mg/kg injected intracoelomically in reptiles
    • Thiabendazole at 110 mg/kg via stomach tube (snakes)
    • Try ivermectin ?
  • Larvae, nymphs - no treatment for these stages.

 

Updated October 2013

 

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