Local media reports quote DPS sources as saying that for unknown reasons, a Nissan Altima veered across the center lane into the path of the oncoming bus.
The bus driver swerved to avoid collision, side-swiping the side of the Altima and then rolling the bus over onto its side at the edge of U.S. Highway 123.
Local emergency personnel responded to the scene including Karnes County EMS and the Karnes City Fire Department Rescue 1 unit, a special unit designated to respond to crashes of this kind when patient extraction may be needed.
Four of the bus passengers were transported to Otto Kaiser Memorial Hospital for treatment to their injuries and three others were airlifted to University Hospital in San Antonio for injuries that were described as non-life-threatening.
The bus carried members of the musical group, Banda el Recodo, based out of who were traveling from Dallas to their next performance in the Rio Grande Valley.
DPS sources say why the 23-year-old driver of the Altima veered into oncoming traffic causing the accident, remains under investigation.