The death of an eight-year-old migrant girl in US border custody has been called “a preventable tragedy” by an independent report.

Anadith Danay Reyes Alvarez died in hospital on 17 May after she fell ill at a border patrol site in Texas.

Investigators later determined that she had an underlying medical condition and was denied repeated requests for care.

A “series of failures” by border agents resulted in the girl’s death, the report concluded.

The report was written by Paul Wise, a paediatrician who is tasked with ensuring that the US Customs and Border Patrol (CBP) comply with providing basic services to migrants under their care.

In his report, filed to in a federal court in Los Angeles on Tuesday, Mr Wise accused Border Patrol of systemic failures that ultimately led to Reyes Alvarez’s death.

These failures “should not be viewed as rare anomalies, but rather as systemic weaknesses that if not remedied, are likely to result in future harm to children in CBP custody,” he wrote.

Reyes Alvarez, a Panamanian girl who was chronically ill with sickle cell anaemia and heart disease, was detained by border agents after crossing the US-Mexico border with her family.

Mr Wise’s report stated that border patrol staff were told about her medical condition when she arrived at the site where she was held in Harlington, Texas. But that information was not passed on to other agents, he wrote.

A few days later, she fell ill with the flu and was given fever medication.

Her health worsened, and she and her mother requested medical care at least three times on the day that she died, Mr Wise wrote. Investigators said her mother had repeatedly asked for an ambulance to be called.

During the final request, Reyes Alvarez appeared to have suffered a seizure and was unresponsive.

“Only after the child lost consciousness and suffered an apparent cardiac arrest was an ambulance called,” Mr Wise wrote. She was later pronounced dead in hospital.

Mr Wise accused medical border staff of poor decision-making when it came to the child’s health.

A separate report by Customs and Border Patrol in June also concluded that staff were not aware of the girl’s chronic illness.

In a previous interview with AP, her mother accused agents of ignoring their pleas for help.

“They killed my daughter, because she was nearly a day and a half without being able to breathe,” she said.

“She cried and begged for her life and they ignored her.”

In a statement on 1 June, the acting head of CBP Troy Miller called Reyes Alvarez’s death a “deeply upsetting and unacceptable tragedy”.

It has put the treatment of migrants under US custody back into the spotlight.

Reyes Alvarez was the second child to die within two weeks, after a 17-year-old Honduran boy, Ángel Eduardo Maradiaga Espinoza, died in a shelter in Florida run by the Department of Health and Human Services’ Office of Refugee Resettlement.