(CNN) - At least 32 migrants have tested positive for influenza at a Texas processing center, prompting border officials to temporarily close the facility's doors to new detainees.
The Centralized Processing Center in McAllen, Texas, reopened Wednesday afternoon, and detainees diagnosed with the flu have been moved to nearby Border Patrol facilities where they can be isolated from others in custody, a US Customs and Border Protection official said.
The decision to shut down intake temporarily at the facility came after the death of a 16-year-old who'd been detained there for days and was later diagnosed with influenza A.
Investigators are looking into whether the migrants who now have influenza had been in contact with the teen, the official said.
The spike in flu cases also comes as immigrant-rights advocates raise concerns about the medical care that detainees are getting inside overcrowded facilities and as top CBP officials warn they're facing a crisis and need more resources to handle it.
A CBP spokesperson said in a statement that officials temporarily suspended intake of new detainees on Tuesday "to avoid the spread of illness," and that by Wednesday afternoon the facility had "resumed normal operations."
"The U.S. Border Patrol moved swiftly to mitigate the spread of any illness," the spokesperson said, "including sterilizing the facility, conducting medical assessments of all individuals and providing treatment on site or in local hospitals as appropriate."
Official: The Texas facility is 'well over capacity'
The center, one of the key sites where CBP processes and temporarily detains immigrants accused of illegally crossing the border, is said to be "well over capacity," according to another CBP official with knowledge of the situation.
The official told CNN the capacity at the McAllen processing center is 1,500. The total capacity for all of the intake centers in the Border Patrol's Rio Grande Valley Sector is 3,363, but officials have seen as many as 8,000 migrants there in recent days, that official said. The Rio Grande Valley sector covers more than 34,000 square miles of southeast Texas, including cities like Brownsville, McAllen and Corpus Christi
Officials are taking extra precautions in light of recent illnesses, another CBP source told CNN.
"We have started taking anyone who even reports a headache to the hospital. You name it, we've seen it recently. Measles, mumps, chicken pox, flu. We don't take any chances." the source said.
For months, CBP has been raising the alarm as it faces more families and children coming across the border -- a shift from previous years when single adult males made up a large number of border apprehensions.
Last week CNN obtained photos showing overcrowding at another CBP facility in McAllen. Those photos, provided to CNN by a source who was concerned about conditions there, showed children sleeping on the ground on rocks, covered by Mylar blankets.
A Guatemalan teen was held there for days
A 16-year old boy from Guatemala who had been detained at the McAllen processing center for six days died on Monday.
Carlos Gregorio Hernandez Vasquez was apprehended on May 13. He indicated to staff at the processing center that "he was not feeling well" and was seen by a contracted nurse practitioner and prescribed Tamiflu before being transferred to the Weslaco Border Patrol Station on Sunday.
"He was assessed and determined to have influenza A," according to a CBP official.
He was the fifth child known to have died after journeying to the US in recent months from Guatemala and being apprehended by US authorities.
Immigrant-rights advocates have called for an investigation, arguing the boy's death highlights the need for more scrutiny of the medical care that detained immigrants receive. It particularly highlights the importance of having more pediatric health experts on hand, they say.
"The concerns we've been flagging for a while have been precisely that overcrowding and lack of proper medical care could lead to tragedies like this," said Astrid Dominguez, director of the American Civil Liberties Union's Border Rights Center.
How flu spreads
Most people with influenza don't die from the virus. But the severity of the illness can depend on a number of factors, including age and what medical care is available.
And overcrowded conditions in detention facilities can provide a fertile environment for the spread of influenza and other illnesses, experts say.
"People can die from influenza. Because a lot of the times you really need good, supportive care. If you go into respiratory failure, you may need to go to the hospital. You need oxygen. You may have a secondary bacterial infection, for which you may need antibiotics," says Dr. Philip Zachariah, an assistant professor of pediatric infectious diseases at Columbia University and a hospital epidemiologist. "Prompt attention to worsening (symptoms) is very important for influenza care, and that is tricky when you have overcrowding. "
Diagnosing illnesses in children can pose particular challenges, Zachariah says.
"Kids compensate longer," he said. "They can look a little sick for a long time, and then suddenly they crash."
CNN's Madeline Holcombe, Rosa Flores, Priscilla Alvarez and Tina Burnside contributed to this report.
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