On the Life-Cycle of Linguatula Rhinaria

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  • George Williams Hooper Foundation, University of California, San Francisco, California

Summary

  1. 1.Natural infections of brown rats (Musnorvegicus) have been observed, and artificial infections of ground squirrels (Otospermophilus qrammurus beecheyi) have been carried out successfully. Both rodents may contribute as intermediate hosts to the cosmopolitan distribution of the parasite.
  2. 2.Self-liberation of nymphs is a postmortal and not an intravital feature in the life cycle of the parasite.
  3. 3.Dogs become infected by nymphs invading the oral cavity or indirectly by nymphs passively regurgitated in the act of vomiting nymph-infested food. Occurrence of active remigration of nymphs from the stomach to the mouth could not be confirmed. Swallowed nymphs, as a rule, are finally digested. Dog is no staple host for nymphs.
  4. 4.Eggs are demonstrable in nasal secretions of final hosts following maturity of the parasite after 6 months throughout the life of the parasite, but only irregularly. Swallowed eggs hatch in the intestine of dogs, are beginning their migration in inner organs but fail to develop. Feces do not contain eggs.
  5. 5.Longevity of adult stages is about 2 years. Localization and symptoms of invasion are described.
  6. 6.Nymphs may invade nasal cavities of house cats. After about 9 days they become expelled without further development. House cats are not storage hosts of the nymph, but accidental intermediate hosts of minor importance.
  7. 7.Feeding of eggs to birds (pigeons) results in formation of parasitic nodules of internal organs containing débris of first stage larvae. Eggs are discharged unaltered by poikilotherm animals (lizards).
  8. 8.Fishes (goldfish and miller's-thumb) digest nymphs.

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