At least four people were killed and more than 40 injured on Sunday when a passenger bus veered off a highway and fell into a ravine in southern Brazil, local G1 news portal reported. A 14-year-old boy was among the fatal victims of the accident, which occurred in the early morning hours near the city of Passo Fundo, in the north of Rio Grande do Sul state. His mother was hospitalized in critical condition in Passo Fundo, the report said. The bus bringing back travelers from a weekend excursion to neighboring Paraguay was heading to the Rio Grande do Sul town of Nova Prata when the driver lost control of the vehicle near a bridge rail, highway officials said. Of those injured, 33 have been hospitalized, some in serious condition, the report said. The tragic death of the boy, Bruno Farina, was "magnified by the fact that he would have turned 15 on Monday," according to the report. His father was reported to be heading to Passo Fundo to be near his wife. The bus company, Turis Silver, said the driver, who survived the crash, was in a state of shock and unable to explain what had happened.