(CNN) Early in the coronavirus pandemic, health officials closely monitored sewage samples for signs of the virus to track where it could be circulating. Now, that technique is being used to detect other infectious diseases: polio and monkeypox.

Some disease detectives in the United States are narrowing their wastewater surveillance efforts to zero in on specific buildings and to identify hot spots for a growing list of diseases. “Some wastewater surveillance is done at the community level, and some is done at the building level, which is a little bit better nuanced in terms of trying to target messaging,” said Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials.

“For example, in some of our jurisdictions, they’ll monitor a large hotel or a prison setting,” she said. “If it pops up there, you can target messaging directly to that building.” A building-level approach to wastewater surveillance is underway at all 11 hospitals within the NYC Health + Hospitals integrated health care system in New York City. The system launched a surveillance program in February to test sewage for coronavirus and flu viruses in wastewater from its hospitals, and the program expanded in August to include testing for polio and monkeypox, according to a company announcement.

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