A rare skin infection has been traced to raw seafood purchased at fish markets in New York City’s three large Chinese neighborhoods, city health officials said Wednesday.

There have been 30 reported cases of infection caused by a bacterium called Mycobacterium marinum, according to the city Health Department.

Symptoms include red, tender lumps and swelling under the skin of their hands or arms. Those infected sometimes also develop swelling or pain in their hands or arms and have difficulty moving their fingers. Anyone who is infected should be treated with antibiotics, the department said.

(AP)