(Adds details on last week's flu cases)

Dec 16 (Reuters) - Flu cases in the United States declined for the third straight week after hospitalizations caused by the virus hit a decade high earlier this month, federal data showed on Friday.

The number of cases for the week ended Dec. 10 were down to 1,763 from 1,974 cases reported for the week ended Dec. 3, according to the Centers for Disease Control and Prevention.

Influenza and respiratory syncytial virus (RSV) are spreading in the United States as temperatures fall, presenting a triple epidemic threat along with COVID-19 during the year-end holiday period.

COVID-19 cases have ticked higher since the Thanksgiving weekend, with a total of 458,986 weekly cases reported as of Dec. 14, according to CDC estimates.

For the week ended Dec. 10, 4,391 cases of RSV were detected in the United States.

Earlier this month, the country recorded its highest levels of hospitalizations from influenza in a decade for this time of the year and 21 children have lost their lives so far. (Reporting by Bhanvi Satija in Bengaluru; Editing by Sriraj Kalluvila and Shinjini Ganguli)