Chile has declared a public health alert over a hantavirus outbreak which has killed three people and infected at least 10 others.

Health minister Jaime Manalich said wildfires in the southern Bio Bio and Araucania regions had driven rats from their normal habitat into towns and cities. He told Chile's Radio Cooperativa on Monday that he fears the situation could get worse.

The hantavirus outbreak began in the El Manzano prison, where two inmates died and 10 others were under observation. On Sunday, two prison workers developed symptoms, and a person camping near Concepción died of the virus.

Hantavirus does not spread between humans, but people catch it when they are exposed to rat droppings and urine. Early symptoms are similar to the flu, including chills, fever and muscle aches. But it can spread quickly, leading to lung and kidney failure. Once it reaches the lungs, the chance of survival can be less than 50%, according to the US National Institutes of Health.

In the Bio Bio region, authorities have been handing out packages of chlorine, breathing masks and pamphlets to people living near the prison in hopes of containing the outbreak.