Which of the following can be found in ocular muscles?
Trichinella spiralis
→ It is a parasite of pig. Man is an incidental host.
→ Infective form is encysted 1st stage larva which is transmitted by eating uncooked pork.
→ Larva penetrates intestine and migrates to muscles where it undergoes encystation.
→ Most commonly involved muscles are extraocular muscles followed by biceps and muscles of jaw and neck.
→ Most infections are asymptomatic.
→ Clinical manifestations may be:

Abdominal - Diarrhea or constipation, abdominal pain, nausea, vomiting.
Hypersensitivity reaction - Fever with eosinophilia, periorbital and facial edema, hemorrhages in the subconjunctiva, retina and nail beds (splinter hemorrhages).
Rarely - Myocarditis with heart failure, encephalitis, pneumonitis.
Symptoms due to encystment of larva in muscles - Myositis with myalgia, weakness.

→ Bachman intradermal test is used for Trichinella.
Educational point
The muscles most often invaded by Trichinella are highly vascularized muscles, such as eye muscles tongue, deltoid, pectoral, intercostal, diaphragm and gastrocnemius.
Trichinella
Ascaris
Enterobius
None