Bird Flu Is Back

Bird flu is back. After a quiet summer, the virus has hit dozens of poultry flocks, resulting in the deaths of nearly seven million farmed birds in the United States since the beginning of September. Among them: about 1.3 million turkeys, putting pressure on the nation’s turkey supply in the run-up to Thanksgiving.

Reports of infected wild birds have also surged this fall, and three states — Idaho, Nebraska and Texas — have identified outbreaks in dairy cows.

The virus often flares up in the fall as wild birds begin migrating south; this year, the uptick is occurring during a government shutdown, as federal agencies that are typically involved in the response are working with skeletal staff.

The Centers for Disease Control and Prevention, which tracks human cases, and the Department of Agriculture, which monitors animal outbreaks, have both suspended routine communication with states, leaving many officials without up-to-date guidance on how to detect and contain the disease, or a clear national picture of the surge.

“Because of the government shutdown, I know less than I would normally know,” said Dr. Amy Swinford, director of the Texas A&M Veterinary Medical Diagnostic Laboratory, which is part of a national network of labs that conducts bird flu surveillance.

The agriculture department did not immediately respond to a request for comment. Emily Hilliard, a spokeswoman for the health department, said the C.D.C. was maintaining its emergency operations center and its ability to detect and respond to urgent public health threats.