When New York City’s health department revealed last weekend that three people had contracted cholera, it was a reminder that the city is not just a world capital of arts, business and the like — but also of exotic diseases.
If a disease has cropped up in the world, there is a good chance it will eventually find its way to New York City through the diverse travelers who cross the city’s borders.
For instance, several people every year are found to have a biblical disease, leprosy, though health officials say no one has to fear catching it in the subway. In 2002, bubonic plague, more commonly associated with the 14th century, found its way to New York City through two travelers who came from a ranch in New Mexico, where the disease is endemic in flea-bitten wild animals like prairie dogs.
Since the anthrax scares after the terrorist attacks of 2001, the city has sharpened its surveillance systems to pick up evidence of biological warfare. Its so-called syndromic surveillance system, which was used during the swine flu pandemic in 2009, looks for unusual patterns of disease in hospital emergency rooms. As part of a federal program to guard against bioterrorism, biosensor detectors in various large cities use a device to draw in air and analyze it for telltale pathogens.
“We definitely are a world capital,” said Dr. Don Weiss, the director of surveillance for the health department’s Bureau of Communicable Diseases. “We have a lot of tourism. We have people who live here whose birth countries are just about every country in the world. We do get some exotic diseases, but not to a point where every day my phone is ringing off the hook.”
For hypochondriacs, New York City offers EpiQuery, an interactive database of communicable diseases from amebiasis to yersiniosis on the health department’s Web site. (EpiQuery lists only diseases that are caught by New York City residents and are reportable by law.)
The city’s database memorializes seven 2001 cases of anthrax and one more, the only case since then — in 2006, Vado Diomande, a maker of African drums, got inhalation anthrax from animal skins contaminated with the anthrax spores.
Malaria is a steady presence in New York City, with about 200 cases a year — a far greater incidence than that of another mosquito-borne disease, West Nile, which infected 42 New Yorkers last year. “The mosquito that transmitted it doesn’t live in this part of the world,” Dr. Weiss said. “People going home to Africa pick it up and bring it here.”
Leprosy, he said, has a long incubation period and was believed to have been brought from other countries, not transmitted within the United States. “We don’t know a lot about how it’s transmitted,” Dr. Weiss said. “It’s not clear whether it takes skin-to-skin contact or can be transmitted through respiratory secretions.”
But he said health officials were not worried about leprosy being passed on in the subway, frightening as that might sound. “Some things can be scary until you have sort of a long period of observation,” Dr. Weiss said. “Three Mile Island, when that happened, everybody was scared out of their wits. But after three weeks, it didn’t blow up, and people said, ‘Oh, it’s probably not going to blow up.’ ”
Centuries of experience have shown that when it comes to epidemics, leprosy “is not as great a concern as tuberculosis, which has been a huge killer worldwide,” Dr. Weiss said.
More prosaically, Lyme disease is on the rise, with more than 500 cases reported in 2008, the last year for which statistics were available, up from 215 in 2000. But here, Dr. Weiss hypothesizes, the higher numbers could reflect increased testing.
Although the city has counted more than 100 rabid raccoons in the past year, there has not been a reported human case of rabies infection in New York City since 1944, according to the health department. “Raccoons are pretty smart and people are pretty smart, and they stay out of each other’s way,” Dr. Weiss said.
Salmonella, he believes, is underreported, because most people with salmonella recover without ever going to the doctor.
And then there are the natural fluctuations. By the second year of West Nile, many of the birds that carried it had acquired immunity, so the incidence fell.
As for cholera, New York City receives reports of about one case a year, almost always found in someone who has traveled abroad, so the three cases of last weekend represent a bit of an increase. All three people attended the same wedding in the Dominican Republic, where health officials said they contracted the disease, which is spread by ingesting bacteria-contaminated food or water. None were hospitalized, and they have recovered, the health department said.
“That to me is what the fascinating thing about it is,” Dr. Weiss said. “All these individual factors that have to do with ecology, population, animals, different people traveling from all over the world. There’s that perfect storm that has to happen, and then you might have something interesting.”