(CNN) Days after a Guatemalan boy died in US custody on Christmas Eve, infectious disease experts say it appears Felipe Alonzo-Gomez likely had the flu, a potentially deadly illness that can often be treated if caught early enough.

US Customs and Border Protection issued a statement Tuesday saying the boy had "possible influenza symptoms" on Monday and was taken to a local hospital.

detailed account of the child's care released by the federal agency does not mention a flu test being administered to Felipe. CBP did not respond to a question from CNN about whether the boy received a flu test.

"This child's death could have been prevented," said Dr. Flor Muñoz, an associate professor at Baylor College of Medicine in Houston.

Muñoz and another pediatric infectious disease expert contacted by CNN said they would have tested Felipe for the flu if he had been their patient, given that it's flu season and he had symptoms of influenza.