CASIMIRO DE ABREU, Brazil (AP) — This small city in the state of Rio de Janeiro is on high alert after authorities confirmed the death of one man by yellow fever and are investigating several other possible cases.

Health authorities this week confirmed that 38-year-old Watila Santos died from the illness on March 11.

Authorities are investigating possible cases involving four relatives of Santos, including a 13-year-old and a 9-year-old.

In the city center and rural areas of Casimiro de Abreu, about 93 miles (150 kilometers) from Rio de Janeiro, a large tent has been set up to vaccinate people. Authorities say around 30,000 of the city's 42,000 people have been vaccinated in recent days.

Yellow fever is transmitted by mosquito and causes fever, body aches, vomiting and sometimes jaundice.