Jason Hardman, Salt Lake City Mosquito Abatement
District operations supervisor, pulls a sample of water while
demonstrating how he looks for mosquito larvae in Salt Lake City on
Wednesday, July 22, 2020.

Kristin Murphy, Deseret News

Does spraying pesticides to control mosquitoes near Great Salt Lake do more harm than good?

By Hannah Petersen, Deseret News | Posted - Apr. 18, 2021 at 8:36 a.m.

SALT LAKE CITY — Some physicians want all mosquito spraying stopped in Utah, claiming alleged harm to residents, but state officials reaffirm their methods of application are safe.

Members of Utah Physicians for a Healthy Environment spoke out this week about dangers insecticides used against adult mosquitoes pose to Utahns' health, publishing a report that lists the downsides of being downwind from mosquito-spraying areas.

The activists listed three major concerns:

  • Neurological problems, including autism, in adults, children and developing fetuses.
  • Decreased fertility in men and women.
  • Utah's overall air quality.

However, the Salt Lake County Mosquito Abatement District countered that efforts to control mosquito populations protect Utahns from illnesses such as West Nile virus.

"Unfortunately, (Utah Physicians for a Healthy Environment's) position does not reflect the current weight of scientific evidence about the risks from treatments for mosquitoes and mosquito-transmitted diseases," said Ary Faraji, executive director of the Salt Lake County Mosquito Abatement District.

Faraji said due to the world's recent experience with COVID-19, public-health decisions based on the best science are important, especially when it comes to the essential service of mosquito control for the protection of Salt Lake City-area residents.

The doctors' group sees it differently.

"The term abatement is a huge euphemism, and we should not let that term obscure the fact that this is a practice that spreads biologic poison throughout our environment," said Dr. Brian Moench, Utah Physicians for a Healthy Environment president and founder.

Group makes case about health concerns

Dr. Courtney Henley, an anesthesiologist, said the more effective the sprayed pesticide, the more likely it was to drift away from the target area and harm surrounding residents, including the unborn.

Moench said pesticides are universally found in the blood and urine of almost all humans, and a study of contaminants in human breast milk from multiple countries shows levels of the most common mosquito pesticide high enough to cause neurological effects.

Dr. Kirtly Jones, an emeritus University of Utah professor of obstetrics and gynecology, said this doesn't just affect the unborn, but even fertility. She said males exposed to even low levels of combined pesticides showed an impact on sperm production.

"The consequences of sperm counts and DNA abnormalities lead to lowered fertility and increased miscarriages in the partners of men exposed. This is heartbreaking for couples trying to have a child," Jones said.

The doctors' group also noted that Utah has one of the highest rates of autism in the nation, with 1 in 32 boys being afflicted with autism and alleged North Salt Lake and West Bountiful areas have at least 77 cases of autism, speculating many more are likely due to the aerial spraying in the Great Salt Lake area.

But Salt Lake County Health Department spokesman Nicholas Rupp said the district only sprays over unpopulated areas.

"We strictly follow the federal lead in these regards," Faraji noted.

Faraji said mosquito-abatement techniques follow the Food Quality Protection Act of 1996.

"The act stipulated that an additional tenfold margin of safety for pesticide risk assessments shall be applied to account for pre- and postnatal toxicity and for any data gaps regarding pesticide exposure and toxicity unless there are reliable data to demonstrate that a different margin would be safe for infants and children," said the Sale Lake County Abatement District.

Dr. Tom Nelson, an emergency medicine physician with the group against spraying, said the volatile organic compounds released by pesticides increase ozone at ground level and the areas don't return to normal pre-spraying levels until one to two days later.

Abatement district officials said there have not been comparable studies showing similar results claimed by the Utah Physicians for a Healthy Environment report.

Rupp said, "the risk of mosquito-borne diseases like West Nile virus far outweighs the risk of appropriately used pesticides as part of a comprehensive mosquito control plan."

What about the sicknesses mosquitoes carry?

Henley said concerns for mosquito-borne illnesses, such as West Nile virus, western equine encephalitis and St. Louis encephalitis were no longer relevant since there have been no outbreaks of the diseases.

The numbers did drop last year.

But Hannah Rettler, an epidemiologist with the Utah Department of Health, said the state saw two human cases of West Nile virus in 2020 as well as a confirmed case of St. Louis encephalitis and one probable case of western equine encephalitis. The number of West Nile cases was higher — 21 — in 2019.

Moench argued the pesticide spraying isn't helping, but rather contributing to mosquito resistance to the chemicals and the evolution of super-mosquitoes.

"Spraying controls not only diseases like West Nile virus but also controls more aggressive species that could carry other public health threats," said Rupp.

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Hannah Petersen


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