Health & Medicine

July 22, 2014

Furor over West Nile spraying in Natomas spurs changes on alerts

Furor over an unscheduled Saturday aerial pesticide spraying for West Nile virus in North Natomas has prompted the local mosquito control district to change its alert process when spraying agricultural fields near residential neighborhoods.

Furor over an unscheduled Saturday aerial pesticide spraying for West Nile virus in North Natomas has prompted the local mosquito control district to change its alert process when spraying agricultural fields near residential neighborhoods.

The spraying, which took place last Saturday and Sunday, surprised many residents in North Natomas.

Those who normally receive email alerts about spray days were not notified because they were signed up only for alerts covering residential neighborhoods, not nearby farm fields.

The spraying on both days was done to control mosquitoes over an 8,000-acre rice farm north of Elkhorn Boulevard.

The spraying was initially meant to start Friday, but weather factors caused it to take place Saturday instead. The Sacramento-Yolo Mosquito & Vector Control District did not update its website with the change, so even those Natomas residents who were checking were unaware.

“In an era of Twitter and Facebook, and almost instantaneous communication, I don’t understand why – when they cancel a flight on one night and they roll it to another – they can’t notify the public of that change,” said resident Mark Smith.

Smith has lived in the Regency Park area of North Natomas since 2008. He was signed up for agricultural spraying alerts, but received no notice of the change in the spraying schedule.

“They should make the public more aware, in general, of where they will be flying on any given day,” he said.

Smith lives a mile away from the rice fields but said that the spraying plane flew very low over his home on Saturday. “It was flying at what seemed to be 300 feet, on multiple passes,” Smith said. “The crop dusters out there don’t do that.”

The plane needed to fly over Smith’s neighborhood to be able to release its pesticide so that wind patterns would carry it to the rice field, said Luz Rodriguez, spokeswoman for the mosquito district.

The outcry over the incident prompted the control district to say Tuesday that it would change how it approaches notifying residents when spraying agricultural fields next to homes.

“After this experience, we have to make sure that we’re notifying residents appropriately,” said Rodriguez. “We have to make sure that we’re posting the applications on our website the day that they occur.”

Rodriguez noted that this was the second spraying this month of the same rice field. Each spraying occurs over two days.

The fields were sprayed on July 12 and 13. Residents didn’t complain about the prior sprayings because the planes didn’t need to fly over neighborhoods to deposit their load on nearby farm fields, and so went largely unnoticed.

When conditions dictate that planes fly over houses in order to hit nearby fields with pesticides, it’s called offset spraying, Rodriguez said. “We have to do a better job explaining the offset spraying,” she said. “Just because we’re flying over your house does not mean that the material is being deposited on the house.”

She said she didn’t have data on how accurately offset spraying targets fields without having chemicals drift onto nearby homes.

The mosquito district uses Vector Disease Control International, a company out of Little Rock, Ark., to conduct aerial spraying. It is one of the few contractors in the country that does extensive aerial mosquito control applications. The pilots use meteorological instruments and GPS to calculate where and how to spray.

The district pays $2 per acre to cover the 8,000-acre field, Rodriguez said.

Rodriguez said the district sprayed in response to the results from mosquito traps collected on Friday.

“A trap had 308 mosquitoes that tested positive for West Nile virus,” said Rodriguez. “The previous week we also had set out a trap that contained 202 mosquitoes that had also tested positive.”

Rodriguez did not say what the total number of mosquitoes was in each trap, nor did she say how many traps were put out in the rice field. While the field is privately owned, the vector control district is in charge of spraying.

The mosquito control district has dispatched pesticide planes into the air this year for the first time since 2012 in response to an uptick in the number of birds and mosquitoes found infected by the West Nile Virus. So far, the district has sprayed a large swath of southern and eastern Sacramento, including such communities as Land Park, Citrus Heights, Orangevale and Fair Oaks.

While the U.S. Environmental Protection Agency says the pesticide used by the district, Naled, does not pose a health risk to humans, epidemiologist Irva Hertz-Picciotto of UC Davis has said greater precautions should be used. She co-authored a recent study that found a link between a pregnant mother’s geographic proximity to where pesticides are applied and higher rates of children born with autism.

In humans, the effects of West Nile virus range from a mild fever to permanent disability and, in some rare cases, death. Many who have the virus show no discernible health effects.

The virus made its first appearance in the Sacramento region in 2003. Aerial spraying began 2005. That year 880 humans tested positive for the virus in California, and there were 19 West Nile-related deaths.

Last year there were 379 confirmed cases of humans with the virus, and 15 deaths statewide. Sacramento tallied 10 confirmed human cases of West Nile, and no deaths.

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