The map of flu activity across the United States continues to darken, both figuratively and literally, as case numbers spike upward in most states, according to the Centers for Disease Control and Prevention (CDC).

There have been at least 24 million illnesses, 310,000 hospitalizations and 13,000 deaths from flu so far this season, according to the CDC. The agency said in its weekly flu surveillance report that seasonal influenza activity continues to increase across the country.

The United States is seeing a second peak in flu cases this season. After doctor’s office visits for flu dipped early this year, they jumped past the previous season peak at the end of last month, with a 30% test positivity rate — and there are still months to go.

Testing results from patients indicate that two strains of seasonal flu that are causing most illnesses — a Type A H1N1 and a Type A H3N2. Health officials are closely watching

For a second time this season, at least 41 states are reporting high or very high levels of the flu. Here's how to stay safe.

The Bronx and Queens zoos are making changes after several birds there died, suspected of having the bird flu. It comes as the state of New York is taking more action to prevent the spread of the disease,

Authorities in New York state have temporarily closed all live poultry markets in New York City and three suburban counties after detecting bird flu at seven markets within the past week, according to a notice on Friday.