CHICAGO (CBS) — The cause of death has been determined for a 5-year-old boy who was living in a migrant shelter in Chicago’s Pilsen neighborhood back in December.

The Cook County Medical Examiner’s office reported Friday that Jean Carlos Martinez Rivero died of sepsis due to an infection with streptococcus pyogenes – the bacterium that causes strep throat.

An infection with COVID-19 and infections two other viruses that cause cold or upper respiratory symptoms – adenovirus and rhinovirus/enterovirus – were also contributing factors, the Medical Examiner’s office said.

The manner of death was natural.

Jean Carlos had been staying with his family at the migrant shelter at 21st and Halsted streets.

On the afternoon of Sunday, Dec. 17, police said Jean Carlos was not feeling well. He was taken from the shelter near Cermak Road and Halsted Street in Pilsen to the University of Chicago’s Comer Children’s Hospital, where he was pronounced dead.

The Martinez Rivero family had been in Chicago only five days before Jean Carlos’ death. 

In a statement, the city offered condolences to the family while also saying: “The City of Chicago coordinates medical screenings for all shelter residents, weekly on-site provider support, on-site vaccination events for COVID, varicella, and flu, and partnerships with a network of community health centers for other healthcare needs. All shelter residents are offered comprehensive medical examinations and care. The City has prioritized the health and well-being of asylum seekers throughout the New Arrivals Mission in partnership with community healthcare providers and Cook County Health, and the Chicago Department of Public Health (CDPH) will continue to monitor and respond to all reportable cases of infectious disease across the City’s temporary shelter system.“

Jean Carlos was survived by his parents and his 2-year-old brother, Isaias.