A couple and their toddler died in Veracruz state when their house was buried, the state's secretary of civil protection Yolanda Gutierrez Carlin said yesterday. The couple's eight-year-old child was rescued and hospitalised.
Another young couple and their three-year-old child were killed when their home was completely swamped by mud.
Two other people were injured in the state capital when their homes collapsed and at least 40 families in the area have been evacuated as a precaution, Carlin said, also warning of increased water levels in the Jamapa river.
The storm has lost strength but rainfall in the country's southeastern states could still cause life-threatening flash floods and mudslides, according to the US National Hurricane Centre.
Earl swept in from the Caribbean at hurricane strength on Wednesday, striking just south of Belize's capital, said the NHC.
The Mexican authorities took no chances, evacuating 300 families living close to a river along the border with Belize in the southeastern state of Quintana Roo for fear of flooding.