Page 47 - MNU-PM503 Parasitology practical book

Pharm D- Clinical Pharmacy Program Third Level Parasitology and virology (PM503)

Definitive host - Pigs, rodents and man.

Intermediate host: - Pigs, rodents and man.

Reservoir host - Pigs and rodents

Infective stage - Trichina capsule (larva) in pork

Mode of infection - Eating raw or undercooked pork containing the

infective larvae.

Diagnostic stage - Encysted larva in striated muscle.

Site of localization - Small intestine

Diagnosis:

- Clinical diagnosis: depends on symptoms and history but it should be confirmed by

laboratory examination or serologic tests.

- Laboratory diagnosis:

1. Blood examination (during the second week): reveals eosinophilia and leucocytosis.

Blood is examined for migrating larvae by adding 20cc. of 3% acetic acid to 5cc. blood,

and after centrifuge, the sediment is examined for larvae.

2. Muscle biopsy (after 2 weeks): demonstration of living larvae in a fragment of

skeletal muscle is the most definitive diagnostic procedure.

3. Intra-dermal skin test (Bachman's test): done after 2 weeks. It is an immediate

hypersensitivity skin test. Intra-dermal injection of 0.1 ml of antigen prepared by

digestion of infected pig’s meat is followed by an immediate reaction in the form of

a wheal surrounded by erythema appearing within 10-20 minutes. It is no longer

commercially available.

4. Serological tests: They are usually negative early in the infection.

5. PCR.

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