Zika versus naled, which one is worse? Miami Beach decides.

On Wednesday morning in the offices of the Miami Beach City Hall hundreds plan to gather to protest the use of naled on Miami Beach as a Zika control measure, with many arguing that naled is more dangerous than the virus itself. Miami Beach Commissioner Michael Grieco has already submitted a resolution to urge Miami-Dade county to stop using naled on Miami Beach that is on Wednesday’s commission agenda.

Here’s the situation: We’ve got this virus that is still kind of mysterious but we know causes serious birth defects (and potentially much worse than that). We’ve also got a few ways to stop its spread — including a pretty serious chemical that is potentially toxic to humans and wildlife.

So now in Miami Beach — the only place in the country where we’ve actually found Zika-carrying adult mosquitoes — residents are left choosing between a virus and a pesticide that is toxic in certain doses (and they don’t know what doses they’re getting).

Making an informed decision depends on clear, consistent, and timely information — but Gov. Rick Scott and the Department of Health haven’t done a very good job of providing that. The result? Residents have lost trust in their own government’s ability to or interest in protecting them during a public health emergency, which jeopardizes their efforts to curb the spread of Zika.

Here are just a few of the questions we’ve overheard in the past few weeks. What other things do you need to know? How can we help you cut through the noise?

Is naled a neurotoxin?

A neurotoxin is a poison that acts on the nervous system. Naled messes with an enzyme called cholinesterase, which is needed for a working nervous system (both mosquito + human). So yes, it is a neurotoxin.

But (and it’s a big but) so are all of these other things we use every day:
Aspartame: a chemical used in artificial sweeteners like Equal.
Sucralose: a chemical used in artificial sweeteners like Splenda.
Diacetyl: a chemical used in microwavable popcorn.
Monosodium Glutamate: a.k.a. MSG, which is in ramen noodles, highly processed chips, and frozen dinners in addition to a bunch of other delicious tasting things.

All of those things probably aren’t great for us, but we use them because maybe we don’t want to eat sugar all day. Or we like snacking while watching movies. Or we don’t have time to cook a meal.

It’s a trade-off, just as it is with Zika and the spraying of pesticides. In safe amounts, approved by the Environmental Protection Agency and the Centers for Disease Control, in theory, they’re not severely harmful to human health.

What is a safe amount of naled?

We don’t do human testing in the United States, so scientists figure this stuff out by testing it on rats first. (A lethal dosage for a rat is 7.7 milligrams of naled per kilogram of the rat’s weight)

The amount that’s being sprayed in Miami is equivalent to 1 to 2 tablespoons of the chemical per acre. So that means the naled is super diluted, and most of the spray you see or feel is the solution they dissolve the chemical in (likely water). The exact concentration, however, is unknown. Experts say as long as the instructions on the label are followed, it should be safe for humans. But it also warns that it should only be used by trained professionals for pest control programs. It does not outline the exact concentration of naled that is safe for human exposure.

The Miami-Dade County mosquito control board, and the Florida Keys mosquito control board did not immediately respond to requests for comment.

At unsafe levels, what can it do to other insects and humans?

It’s very toxic to bees and if it’s sprayed near them it should be done at night when the bees are not out. (In South Carolina, government officials taking prevention measures sprayed naled at dawn when the bees were out, killing 2.5 million commercial honey bees.)

At unsafe levels for humans, it can lead to everything from a mild headache to death, depending on the concentration. It’s also toxic to birds and aquatic life at those levels. Again though, the concentrations being sprayed in Miami-Dade aren’t close to those levels, according to mosquito control experts.

What can Zika do?

Zika can cause everything from a mild rash to microcephaly in growing infants. There’s still a lot we don’t know about the virus but the CDC says this is the full list of things they’ve linked it to so far: “The most common symptoms of Zika virus disease are fever, rash, joint pain, and red eyes. Other symptoms include muscle pain and headache. Many people infected with Zika won’t have symptoms or will have mild symptoms, which can last for several days to a weeks.”

(The CDC is also looking into whether it causes Guillain-Barré syndrome, which causes muscle weakness and paralysis, there are a few cases that indicate some relationship.)

For pregnant women, it’s a bigger problem. Zika infection can cause a range of things in the fetus, from eye and brain abnormalities severe birth defects like microcephaly.

Is there actually evidence that the aerial spraying in Miami Beach will kill mosquitoes?

It’s debatable. CDC Director Tom Frieden told reporters that in Wynwood, the aerial spraying killed more than “90 percent of mosquitoes in traps.” Other than that the CDC cited one study that wasn’t peer-reviewed, meaning it wasn’t double and triple checked by a community of scientists, as additional support of that 90 percent figure.

Plenty of studies do show the effectiveness of aerial spraying, like this one and this one, but not nearly at those efficacy rates.

Frieden also told reporters that spraying naled wouldn’t be as effective in Miami Beach because the airplanes that spray it have to fly pretty low — 100 feet above the ground — and when there’s not much wind. And in Miami Beach with high rises and the ocean breeze, that’s something that’d “be very difficult to do,” Frieden said.

But naled was sprayed last week anyway — and there’s been no explanation of why, or whether it was ordered by the CDC or the local government.

Is naled banned in the EU?

The Florida Department of Health says no, it’s not. But pretty much everyone else says yes, it is, including the British public health department. Not a good look for the DOH, which hasn’t been the best at communicating why it’s making the decisions it’s making.

Why are we using it here?

It’s a cost/benefit analysis. Our climate is different from the EU (hot and humid), so we’re more susceptible to the spread of mosquito-borne viruses carried by the A. aegypti mosquito. Many of the mosquitoes here have developed resistance to other insecticides because of overuse so this is the next most effective thing.

Why don’t we use something else?

We are using other things too. We’re using ground foggers which contain something called pyrethrin. It’s an insecticide, made up of a mixture of six chemicals that are toxic. It excites the nervous system of the insects that eat it.

We’re also using BTI in aerial sprays. The full name is bacillus thuringiensis israelenis. It’s a larvicide so it kills the mosquitoes before they can become adults.

Here’s a whole list of all the things we’re using to keep Zika away.

Is Broward using naled?

Nope. They’re using BTI, which targets larvae. That’s because they haven’t found any adult mosquitoes carrying Zika, so they don’t need to use naled or other insecticides, a.k.a. things that kill adult mosquitoes.

Does Gov. Rick Scott’s wife own a mosquito control company and are they making money off of Zika spraying?

Gov. Rick Scott’s wife co-owns a private investment firm that has a stake in a company called Mosquito Control Services LLC which is “licensed throughout the Gulf Coast, including Louisiana, Georgia, Mississippi, Alabama and Florida.”

But Mosquito Control Services is not a registered state vendor — that means state funds can’t go to that company and the company doesn’t appear to be involved in the spraying. That doesn’t mean it can’t register as a state vendor later, though.