The top U.S. infectious disease expert warned Sunday of a possible, upcoming spike of the coronavirus.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaking on "This Week" on ABC-TV, said the infection rate would not "all of a sudden turn around" and in the coming weeks, following the recent Thanksgiving holiday, "We may see a surge upon a surge."

Also Sunday, Dr. Deborah L. Birx, the White House coronavirus response coordinator, said on "Face the Nation" on CBS-TV, that people who traveled during the holiday "have to assume that you were exposed, and you became infected and you really need to get tested in the next week." She also called on people who had traveled during the holiday to avoid people older than 65 or who have an underlying disease.

The U.S. has 13.3 million of the world's 62.7 million COVID-19 cases, according to the Johns Hopkins Coronavirus Resource Center. The U.S. has more cases of the virus than any other country in the world. India and Brazil follow the U.S. in case numbers with 9.3 million and 6.3 million respectively.

India recorded nearly 42,000 new COVID infections Sunday, according to Johns Hopkins.

In Europe, some countries are hoping for a continent wide agreement to shut down ski resorts during the Christmas holidays to help prevent spreading the coronavirus. No unified pact, however, has yet been reached.

The World Health Organization warned Monday that malaria deaths will likely exceed COVID deaths in Africa because of the health care disruptions caused by the pandemic.