Officials said on Wednesday the boy was transferred to an Office of Refugee Resettlement (ORR) shelter in Texas on April 20.
“Upon arrival to the shelter the minor did not note any health concerns,” Evelyn Stauffer, a spokeswoman for the Administration for Children and Families, which oversees ORR, said in a statement to local media.
But the next morning, he had fever, chills and a headache and was taken to a hospital, where he was treated and released that day.
He didn’t improve and was sent to another hospital, where he was transferred to a third facility, a children’s hospital. He died on Tuesday.
Stauffer said the cause of death is under review.
Since 2015, two other unaccompanied children have died in the custody of the Department of Health and Human Services.
Last year, two accompanied children also died while in custody at the border in separate incidents.
Tuesday’s death comes as a surge of unaccompanied children and migrant families cross the US-Mexico border.
The Congressional Hispanic Caucus on Wednesday called for the Department of Homeland Security and the Department of Health and Human Services to investigate the child’s death.
Beto O’Rourke, a Texas politician and presidential candidate for the 2020 Democratic nomination, tweeted that he was “very saddened” by the news.
“We must focus on the wellbeing of these children above any other concern. If we sacrifice humanity for security, we’ll lose both,” he added.
And Families Belong Together, a coalition of hundreds of organisations fighting to keep families together, called the death a “pattern”.
“Another migrant child has tragically died in federal custody. There is no denying that this is a pattern,” the group tweeted. “Refugee and asylum-seeking children hoping for better lives are dying at the hands of this administration. Our coalition demands accountability.”
Another migrant child has tragically died in federal custody. There is no denying that this is a pattern. Refugee and asylum-seeking children hoping for better lives are dying at the hands of this administration. Our coalition demands accountability. https://t.co/DbvuaIiYro
— Families Belong Together (@fams2gether) May 1, 2019