NORTHFIELD, Ill. (WLS) --There are now 13 cases of the Zika virus in Illinois, but in each case, health officials say the affected person traveled out of the country.
Still, there are growing concerns about the virus and experts want to clarify that the disease cannot be contracted locally.
"We're fortunate in that among the 60 or so mosquito species that live in Illinois, we don't have 2 mosquito species that are capable of transmitting Zika virus," said Roger Nasci, North Shore Mosquito Abatement District.
Nasci says the West Nile virus remains the biggest concern in this area as the weather gets warmer. Already, workers have found mosquito larvae during their inspections of the thousands of catch basins in the area.
"We are seeing a normal beginning to the season, perhaps earlier than usual likely because El Nino effect on winter temperatures," Nasci said.
Mosquito larvae have been collected in standing water, which is why the Metropolitan Water Reclamation District says rain barrels are an ideal choice for home owners. They're offering the 55-gallon barrels for free to dozens of communities.
Catherine O'Connor, the director of engineering, says barrels are eco-friendly and they keep rain water from possibly flooding the sewer system. But she says they can also prevent areas of standing water.
"If you have standing water in your back yard, it's better to capture the water in a mosquito-proof fashion than have standing water in your back yard that will attract breeding mosquitos," O'Connor said.
But according to the Centers for Disease Control, rain barrels are a potential breeding ground for mosquitoes. Nasci says the collected water needs to be treated with an environmentally-safe insecticide, and the barrels should be routinely inspected for cracks and emptied at least once a week.
"The ones that we've seen at the MWRD are well designed but need to be properly installed so that mosquitoes can't get in and lay eggs in water," Nasci said.