What's worse: getting the Zika virus, or being exposed to potentially harmful chemical pesticides?
As more states are beginning to deploy aerial spraying campaigns to kill off mosquitos, some scientists are warning the chemical spray could be harmful to humans in the long term.
Spraying Naled over Florida
More than 1,000 people in the continental U.S. have been infected with the virus, which can cause severe birth defects like microcephaly.
Airplanes have already been flying over Miami spraying an EPA-approved insecticide called Naled, a neurotoxin that kills adult mosquitos.
Benefits vs. risks
But some scientists say high exposure to the chemicals used in Naled can have negative long-term health effects for humans.
"I think we need to take a step back and recognize that we should always look at these interventions in terms of risk versus benefit," said Dr. David Perlmutter, a board-certified neurologist. "Sure there is a benefit here, but there is a risk."
Several studies have already shown Naled kills bees and butterflies, which are important pollinators that help with agriculture.
But it's not just insects -- there are other studies that suggest the chemicals in Naled could be harmful to humans.
Animal testing found high exposure to trichlorfon, one of the main ingredients in Naled, could cause cancer and birth defects.
When the offsprings were examined at birth, there was a severe reduction in brain weight in the case of trichlorfon.
Impact on brain development
Scientists at the University of Oslo tested trichlorfon on guinea pigs. They found that injections of the chemical in pregnant guinea pigs impacted the brain development of the fetuses.
"When the offsprings were examined at birth, there was a severe reduction in brain weight in the case of trichlorfon and dichlorvos, but not after treatment with the other organophosphates," the study says.
Outlier or alarm?
Some scientists argue that studies like these are outliers, because the test animals experienced a much higher exposure to the chemicals than humans living in an aerial spraying zone typically would. But others aren't so sure.
A 2014 study by scientists at the University of California, Davis found that pregnant women living within a few miles of farms where pesticides like Naled were sprayed had a 60 percent increased risk of their child developing autism.
"I think we're just beginning to understand that we've got to look at the dangers of these types of pesticides through a much broader lens," Dr. Perlmutter said. "We should prove safety and not just say well because it hasn't been proven detrimental it's ok. That's not good enough."
And other experts say Naled isn't even the most effective way to combat the Zika Virus.
Better strategies to combat Zika
"The most effective way to combat Zika is for people to get rid of their water containers," said Joseph Conlon, a spokesman for the American Mosquito Control Association.
"Unfortunately, you can't get people to get rid of their water containers."But in an emergency situation, Naled is the best weapon health workers have to fight mosquito-borne diseases.
We'd rather not do that, we would rather just have people pick up their trash and get rid of their water.
No Naled in Puerto Rico
"Given the current situation of the Zika virus and the local transmission, they're going to apply these materials while there is a human health risk to try and limit the spread of Zika," said Michael Raupp, a professor of entomology at the University of Maryland.
In Puerto Rico, where health officials say there are over 1,500 new cases of Zika reported each week, the government refused to use Naled due to environmental and health concerns.
But Naled is still on the Zika response plan in other U.S. cities like New Orleans. Duane Gubler, a professor at Duke-MUS medical school, said without more research, mosquito-borne diseases like Zika will only get worse before they get better.
"Health authorities, national health authorities and endemic countries need to recognize this and get serious about developing long-term sustainable programs to contain these diseases," he said.
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