Aerial spraying for Zika virus begins in Miami Beach

Aerial insecticide spraying to combat mosquitoes carrying the Zika virus is underway in Miami Beach.

A plane carrying the insecticide naled released the spray over the targeted area before on Friday. The next round is scheduled for 6 a.m. on Sunday.

Some residents oppose the spraying, citing the potential for harmful effects. But county officials say the low concentration of naled won't harm them.

"We are concerned that the naled actually has more of a potential risk of creating the problems we are trying to avert than the actual concern with Zika," area resident Brik Viera said.

Local television stations reported that some parents kept their children home from school on Friday because of the spraying. The aerial spraying targets adult mosquitoes; different pesticides for larvae will be sprayed on the ground.

The touristy South Beach area of Miami Beach is the second site declared an active zone of Zika transmission by mosquitoes on the US mainland. The discovery in August led the US Centers for Disease Control and Prevention to include a section of Miami Beach in a travel warning issued for pregnant women.

Earlier in the summer, a travel warning was issued for Miami's Wynwood arts district, which is popular for day trips.

South Beach also became the first place on the mainland where the virus was isolated in mosquito samples, with health authorities reporting last week that three batches of the insects tested positive for Zika. Florida's agriculture department said Friday that one more batch from the area had tested positive.

Statewide, an additional 2,900 batches of more than a dozen insects each have tested negative for the virus, state officials said in a news release.

Zika infection can cause severe brain-related birth defects, including a dangerously small head, if women are infected during pregnancy.

Of Florida's 56 non-travel-related Zika cases, 11 have been traced to Miami Beach and 29 to Wynwood. The rest are being considered isolated cases and have not prompted authorities to issue warnings of local transmission.