The infection has a world-wide distribution, but the infection tends to be seen more often in certain ethnic groups because of dietary practices:
(1) Russians
(2) Finns
(3) Scandinavians
(4) residents of the Baltic states
Infection is acquired after the ingestion of raw, poorly cooked, or pickled freshwater fish.
This may include:
(1) ceviche (raw fish marinated in lime) in Latin America
(2) sushi prepared from freshwater fish
(3) sampling prior to cooking to determine proper seasoning (gefilte fish)
Prevention - either of the following:
(1) thorough cooking
(2) freezing for 24-48 hours at -18°C
However, these steps change the taste, and so may be avoided by the serious gourmand. In theory food irradiation should kill the larvae and preserve the taste.
