Health officials warned people to take precautions when handling raw fish after at least 30 people who bought seafood in Chinese markets contracted a rare skin infection. Does it really matter which market the fish come from? NYT By MARC SANTORA Published: March 5, 2014 At least 30 people have contracted a rare skin infection after buying seafood at markets in Chinese neighborhoods across New York City, prompting health officials to issue a warning to consumers and market workers to take precautions when handling raw or live fish. The source of the outbreak was unclear, but health officials said that all of the people who were infected had bought fish at markets in Sunset Park, Brooklyn; Flushing, Queens; or Chinatown, in Manhattan. There was no evidence that eating fish from any of those markets could cause illness, officials said. “People are encouraged to wear waterproof gloves in their home when preparing live or raw fish or seafood that came from a market in Chinatown, especially if they have cuts or abrasions,” the New York City Department of Health and Mental Hygiene said in a statement. Dr. Jay Varma, the deputy commissioner for disease control, said the bacterium that causes the infection, Mycobacterium marinum, is common in fish and aquariums but rarely causes infections in humans. “If you were to ask 100 doctors if they had seen a case, you would be lucky to find one who had,” he said. “For us to see 30 cases clustered like this is very unusual.” The investigation into the source or sources of the outbreak is complicated, in part because the infections tend to take weeks to show symptoms. In a typical case, Dr. Varma said, the first signs of infection are bumps under the skin or tender lesions. From there, it worsens into a wound that will not heal. The infection can spread to the soft tissue below the skin and then into tendons and muscles. It is treatable with a targeted combination of antibiotics. But if the infection goes untreated for a prolonged period, it can require surgery to repair damage to nerves, tendons and muscles. Dr. Danny Fong, a hand surgeon who works in Manhattan’s Chinatown and is the president of the Chinese American Medical Society, said he saw perhaps one case a year. The source of the infection has been varied, he said. For instance, he had one patient who worked on boats and most likely got infected after scrubbing barnacles off a ship’s hull. Dr. Fong was not alarmed when he saw an infected patient in August. But then in September he saw another. Then another. Then another. By February, at least 15 people had shown up at his office with the type of lesions that are the hallmark of the condition. He alerted the health department a little over a week ago. Since then, the department has identified an additional 15 cases. “We anticipate we will definitely learn about more,” Dr. Varma said. Dr. Fong said that doctors in the community have been warned to be on the lookout for the infection, and that he could only guess as to the cause of the outbreak. Most of his patients, he said, were infected after skin punctures from fish bones. But one patient fell ill after cutting himself on a lobster. While all of the patients were infected after handling live or raw seafood, health officials could not rule out other possible sources of the infections, such as the water in the fish tanks. So far, no fish markets have been closed; Dr. Varma said he suspected there were multiple problematic locations. “We don’t think it is one market,” he said, “but it could be.” The investigation was in its early stages. City, state and federal officials were examining how seafood tanks at the markets are cleaned, and if practices have changed recently. They were also looking at the origin of the fish sold at these markets and whether any new species were being sold. The warnings did little to slow the activity at fish markets across the city on Wednesday, with many shoppers unaware of the warnings. In some neighborhoods, the haggling and trading takes place on the sidewalk. At the Asian fish markets in Flushing, the activity takes place inside, but is no less frenzied. Handwritten cardboard signs in Chinese stick out of the ice identifying the day’s catch: yellow croakers, sea bass, razor clams. Fish sellers in a handful of shops in Brooklyn and Queens wore gloves or used clear plastic bags when handling raw or live fish. “Everybody knows if you don’t use gloves it’s very dangerous, even when you clean the fish,” said Nicky Chen, the manager of S&P Seafood on Eighth Avenue. He wore thick rubber gloves as he sold fish, clams, crabs and lobsters. Many customers, however, seemed comfortable touching the fish barehanded. Eli M. Rosenberg and Jeffrey E. Singer contributed reporting.