Health officials say more than 200 people in Los Angeles County have contracted West Nile virus this year and 17 have died.
The Los Angeles Times reported that this is the third highest level of infection in county history — and it's expected to continue to rise.
Officials say recent record-high fall temperatures are at least partly to blame.
Hot weather causes the virus that is passed from mosquitoes to people to replicate faster.
Greater Los Angeles Vector Control District spokesman Levy Sun says until the weather cools and kills off this year's mosquitoes the virus will continue to spread.
Most people infected by West Nile show no symptoms.
One out of every 150 become seriously ill, however, with such maladies as meningitis, vision, loss, coma and paralysis.