A Taiwanese man who recently sought medical care for a headache and neck stiffness was confirmed positive for the parasitic infection, angiostrongyliasis, according to a Taiwan Centers for Disease Control press release Feb. 4.
The timeline for the 48-year-old man was he presented with symptoms at the end of Dec. 2012, several weeks later the diagnosis of Angiostrongylus infection was confirmed at the hospital.
The investigation by public health officials into the case revealed he consumed snail soup several days prior to his disease onset. The case might have become infected for ingesting the parasite larvae because the snail might have been undercooked.
The man is responding well to antiparasitic treatment and recovering.
Last year in Taiwan, the Taiwan CDC recorded nine cases of angiostrongyliasis, three in locals and six in Thai nationals.
Of the 9 cases, 8 consumed land snails or apple snails prior to disease onset. All recovered from their illness.
What is angiostrongyliasis?
It is an infection caused by the rat lungworm, Angiostrongylus cantonensis. This is a parasitic infection in rats where it matures. Mollusks like snails and slugs pick up Angiostrongylus larvae by ingesting them in rat feces.
How do people get this parasite?
Infection is by accidentally or intentionally ingesting raw snails and slugs. Lettuce and other leafy vegetables may also be a source if contaminated by small mollusks. Eating raw or undercooked prawns and crabs that have ingested mollusks may also be a source of infection.
What are the symptoms and disease?
Angiostrongylus cantonensis infection is usually asymptomatic or mildly symptomatic. Symptoms usually appear in 1-3 weeks. The most serious disease is eosinophilic meningitis. The symptoms can include headache, stiff neck, tingling or painful feelings in the skin, low-grade fever, nausea, and vomiting. The spinal fluid exhibits eosinophilia of over 20%. Deaths are rarely reported.
Symptoms may last for weeks to months.
How is this infection diagnosed?
The presence of eosinophils in the spinal fluid and a history of eating raw snails suggest angiostrongyliasis. Finding the worms in spinal fluid or at autopsy is confirmation.
What about treatment?
Treatment is usually not necessary. The parasite dies over time since it can’t mature and complete its life cycle. Usually treatment of symptoms; headache medicine, steroids are all that is needed. Treatment with anti-parasitic drugs is generally ineffective against angiostrongyliasis.
How do you prevent getting angiostrongyliasis?
• Don't eat raw or undercooked snails or slugs.
• Cook crabs and prawns to kill the larvae.
• Thoroughly clean lettuce and other produce.
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