facebook_pixel

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.

  • weezilla

    I appreciate the somewhat neutral tone of writing. I did some perusing of a toxicology doc http://pmep.cce.cornell.edu/profiles/extoxnet/metiram-propoxur/naled-ext.html

    Some back-of-the-envelope calculations. I assumed about 25g/acre. If the mist fell straight down, that would be about 0.5mg per square foot. The lethal dose that kills half a population of rats by inhalation is 7.7mg/kg (aka the LD50). In mice, inhalation LD50 is 156kg–big difference. It might be more or less for humans. Let’s assume the more severe case and extrapolate the rats number. For a 70kg human at 7.7mg/kg, about 500mg inhalation is a lethal dose. Recall the rough calculation of 0.5mg per square foot. That’s 0.1% of the LD50. This might be hopeful or not hopeful depending on important, further assumptions. But, there are too many details to consider that might make that 0.1% of LD50 good for us or bad for us. These calculations are incredibly rough and neglectful.

    For comparison, the OSHA guidelines for Naled are 1800mg/meter^3 for immediate and life threatening inhalation toxicity, and 3mg/meter^3 over 8 hours of inhalation exposure.

    This neglects all sorts of things. Are there centroids where the naled might collect in greater concentrations due to weather conditions? Does the naled coat the surfaces of things, or stay airborne and blow away, or what combination thereof? How much is ingested upon breathing in? What is the vertical spread of the Naled as it falls (which I completely neglected).

    The better news is, animals tend to be much more tolerant of skin contact and ingestion of naled, requiring something like 1000mg/kg for skin contact LD50, and 50 to 500mg/kg of daily exposure. Also, naled decays almost entirely within weeks in the presence of water (which we have plenty of in the air in Miami).

    In summary, these numbers are not accurate, and there is a chance they are plain wrong due to some assumptions. Don’t quote them.

    Yet, I don’t like the idea of dispersing Naled like this. Naled is pretty rough stuff, and small amounts over a large population may cause problems. It should be a last resort, where it’s to prevent an impending zika epidemic and there are no other options.

    • weezilla

      One of the kickers is: naled in the bloodstream may cross the placenta. Naled is readily absorbed into the bloodstream through inhalation. One of the Zika scares is pregnancy problems (which Naled may cause?).

  • Maudie Valero

    Exactly as @skipvancel:disqus is saying… I don’t use it at all, and at least it will be my decision to do so, not in the case of #naled. Very bad example when most people who consume that staff is not in good health, better to write a note about the harm of those, not to use it as reference to justify other harmful chemicals…

  • Maudie Valero

    Exactly as @skipvancel:disqus is saying… I don’t use it at all, and at least it will be my decision to do so, not in the case of #naled. Very bad example when most people who consume that staff is not in good health, better to write a note about the harm of those, not to use it as reference to justify other harmful chemicals…

  • Zika has NOT been confirmed to cause microcephaly. They got that information from a small town in Brazil with a high concentration of the Zika virus BUT that towns water registered super high levels of a toxin in their drinking water which came from all the pesticides the gov sprayed and to cover it up they blamed it on Zika. In Colombia the majority of the population has come into contact with the Zika virus meaning they caught Zika and they have no reports of microcephaly. The Zika is not a scary virus, it’s less harmful than chicken pox, and the symptoms only require tylenol and bed rest. And once you get it, you build immunity towards it. This is all a cover up to blame illnesses on a little mosquito instead of these pesticides we are forced to ingest and be exposed to. I see those chem trails in the sky, we all know they’re spraying junk on us. But please don’t say Zika CAUSES microcephaly because that has never been proved and it’s the very idea they’re using to force us to comply.

  • Zika has NOT been confirmed to cause microcephaly. They got that information from a small town in Brazil with a high concentration of the Zika virus BUT that towns water registered super high levels of a toxin in their drinking water which came from all the pesticides the gov sprayed and to cover it up they blamed it on Zika. In Colombia the majority of the population has come into contact with the Zika virus meaning they caught Zika and they have no reports of microcephaly. The Zika is not a scary virus, it’s less harmful than chicken pox, and the symptoms only require tylenol and bed rest. And once you get it, you build immunity towards it. This is all a cover up to blame illnesses on a little mosquito instead of these pesticides we are forced to ingest and be exposed to. I see those chem trails in the sky, we all know they’re spraying junk on us. But please don’t say Zika CAUSES microcephaly because that has never been proved and it’s the very idea they’re using to force us to comply.

  • Vice-Queen Maria

    By the way, I heard the entire meeting this morning. Miami Beach decided nothing. #nonaled #naled #zika

  • Vice-Queen Maria

    By the way, I heard the entire meeting this morning. Miami Beach decided nothing. #nonaled #naled #zika

  • Vice-Queen Maria

    Great report, Roshan. Thank you. I have compiled a list of 40+ testimonials from people who’ve been in the spray zones (Wynwood and Miami Beach) and reported symptoms after the sprayings. The information has been shared with the politicos and some key players. There’s also photographic evidence of symptoms and dead fauna. The CDC can say what it wants, 40 + people can’t all be part of a nocebo effect, can they?

  • Vice-Queen Maria

    Great report, Roshan. Thank you. I have compiled a list of 40+ testimonials from people who’ve been in the spray zones (Wynwood and Miami Beach) and reported symptoms after the sprayings. The information has been shared with the politicos and some key players. There’s also photographic evidence of symptoms and dead fauna. The CDC can say what it wants, 40 + people can’t all be part of a nocebo effect, can they?

  • Skip Van Cel

    I don’t eat equal, aspartame or the other products you mentioned. And if I have to trust my government to spray to apply it correctly, you have completely lost me.

  • Skip Van Cel

    I don’t eat equal, aspartame or the other products you mentioned. And if I have to trust my government to spray to apply it correctly, you have completely lost me.

  • James Echols

    To be clear, Zika has not been fully confirmed as a cause of microcephaly. There is a strong correlation, but the causation is still unconfirmed. So, we do not “know” it causes birth defects, but we are pretty darn sure that it might. Still, it is good to be clear in this situation.

    Also, “The most common symptoms of Zika virus disease” are none. 4 out of 5 people who get it will be asymptomatic, which means they show no symptoms. This is an important distinction because you may have and not know it, or, more importantly, your sexual partner may have it and you not know it.

    • Roshan

      Hi there James. Please see this advisory from the CDC: “CDC scientists announced that enough evidence has accumulated to conclude that Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects.”

      Full text here: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html

  • James Echols

    To be clear, Zika has not been fully confirmed as a cause of microcephaly. There is a strong correlation, but the causation is still unconfirmed. So, we do not “know” it causes birth defects, but we are pretty darn sure that it might. Still, it is good to be clear in this situation.

    Also, “The most common symptoms of Zika virus disease” are none. 4 out of 5 people who get it will be asymptomatic, which means they show no symptoms. This is an important distinction because you may have and not know it, or, more importantly, your sexual partner may have it and you not know it.

    • Roshan

      Hi there James. Please see this advisory from the CDC: “CDC scientists announced that enough evidence has accumulated to conclude that Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects.”

      Full text here: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html