ORGANISM 4: Trichinella spiralis
GENERAL CHARACTERISTICS
COMMON NAME: Trichina worm.
GEOGRAPHICAL DISTRIBUTION: Worldwide; prevalent in pork eating countries (USA
and Europe).
PATHOGENESIS: Larval invasion of striated muscle and vital organs, eosinophilia,
acute interstitial inflammation, pneumonitis, pleurisy,
encephalitis (periorbital swelling), meningitis, nephritis, deafness,
peritonitis, eye and brain trauma, myocarditis.
HABITAT
ADULTS: Small intestines.
LARVAE: Striated muscle.
INTERMEDIATE HOST: Carnivores; pigs. One host may serve as both definitive
and intermediate host.
RESERVOIR HOST: Pigs, wild boars, rats, bears, walruses, and many other
carnivores.
INFECTIVE FORM: Encysted larvae.
MODE OF INFECTION: Ingestion.
SPECIMEN OF CHOICE: Tissue biopsy.
Figure 4-25. Life cycle of Trichinella spiralis.
MD0842
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