Where do spot-on flea products go, and how fast?

May 29, 2019 12:06 PM

The vet pressured us into applying Cheristin (spinetoram @ 11.2%) for our cat's fleas. But we have a newborn! Is she going to get exposed to this? So far, we have the cat in the garage, but how long should we keep him sequestered?

The dose of cheristin contains 91 mg. The no-observed-adverse-effect-level (NOAEL) seems to be 2.49 mg / kg. Then the standard is to apply a 10x - 100X safety factor, right (especially since I'm assuming that the risks to humans under a month old have not been well-characterized)? She weighs a bit more than 4 kg, so the math would say that her daily exposure should be under 0.1 or 1.0 mg, or 0.1-1 percent of the topical treatment that was applied. Is it unreasonable to think that this amount could be coming into our household environment?

Where does the product go? The manufacturer insists it isn't absorbed by the animal. They state that it spreads across the body throughout the fur and stays there for 30 days. But how does it come off? They claim it doesn't come off when you pet the cat. The components' half life varies a lot according to conditions, but in aerobic soil (is that the equivalent of cat fur in a shady garage?) they ranged from 3 to 29 days.

I have called the EPA and the manufacturer so far but haven't really gotten good answers on this. The party line seems to be "it is no risk to the public once the product dries." But another spot-on treatment (fipronil) was found in households (e.g., on residents' socks and hands and on the blankets where pets sleep) over a four-week study period, comes off in dog bath water even at 28 days, and ends up at sewage treatment plants. Since spinetoram still kills 96% of fleas at Day 37, I'm concerned that the chemical will still be shedding off the cat for awhile and that we need to keep the cat in the garage and outdoors for over a month. But then I think, that sounds extreme.

Thoughts?

posted by slidell to Health & Fitness (11 answers total)

I think that keeping the cat in the garage at all is extreme. This article in the Federal Register, says there are no apparent neurotoxic effects in infants and toddlers, and in fact:

3. Conclusion. EPA has determined that reliable data show the safety of infants and children would be adequately protected if the FQPA SF were reduced to 1X.

If you're still worried you can call the Poison Control Center and ask them, and keep the cat out of the baby's room.

(Also, consider that your cat is the same size or smaller than your baby and you're not concerned about the effects on the cat.)
posted by telophase at 1:05 PM on May 29, 2019 [11 favorites]

If in the USA, have you tried calling the Infant Risk hotline? They may know more specifically how that drug may interact with your newborn.
posted by jillithd at 1:08 PM on May 29, 2019 [1 favorite]

Also, the newborn is not going to be in direct contact with the cat, right? Would washing your hands between petting the cat and touching the baby make you feel better?
posted by fiercecupcake at 1:16 PM on May 29, 2019 [1 favorite]

Presumably the cat and the newborn are not interacting? As a newborn they’re probably not even in contact with things the cat was in contact with. I think you’re fine with treating the cat like normal. Wash your hands thoroughly after administering before handling your baby of course but other than that I wouldn’t worry about airborne chemicals.
posted by like_neon at 1:21 PM on May 29, 2019

If it were me, & if you haven't already, I'd ask if there were other methods of flea control like maybe some kind of bath that wouldn't require the substance to sit on the cat's skin. If you felt pressured you can always get a second opinion.
posted by bleep at 1:22 PM on May 29, 2019

Being able to detect the pesticide after many days has no bearing on whether it's present in hazardous amounts - that comes down to the chemical structure of the pesticide and the limits of scientific equipment rather than how toxic it is.

I apply spinetoram to plants at work, and it's a pretty benign insecticide - applicators, who are likely applying this to acres of plants, only need long pants, long sleeves, socks, and shoes for protective equipment (and pesticide labels are EPA and FDA approved and is typically pretty conservative). People can go in and handle plants treated with it without PPE after four hours. I wouldn't extrapolate Cheristin's properties too much from other spinetoram products, but I think you can let the cat out of the garage.
posted by momus_window at 1:28 PM on May 29, 2019 [5 favorites]

The EPA literally has whole departments of Ph.D scientists whose entire job is to do this math in detail, including the math on “where does it go” and “how much could a baby get exposed to.” Current politics notwithstanding, they generally tend to make cautious assumptions that err on the side of being protective. I would feel OK trusting them if they say it’s safe when used as directed.

They did not detail their exposure calculations in that fact sheet, but they do mention that they calculated risks for toddlers based on exposure from application to plants in the yard, and found a margin of exposure (MOE) of about 970 — meaning they calculated that the toddler would get 970 times less exposure than it would take to cause a problem. That’s a pretty wide margin of exposure. And toddlers are a lot more active than newborns in terms of touching and licking things (and yes, the calculations take that into account).
posted by snowmentality at 3:12 PM on May 29, 2019 [4 favorites]

I totally get when you have a newborn they seem almost unbearably fragile, but they are tougher than you think - way tougher. People have been - and still are - having babies in much more chemically and otherwise hazardous environments than you, and those babies turn out 100% okay.

Here is a great fact sheet about this pesticide.

Highlights:

What are some signs and symptoms from a brief exposure to spinosad?

Spinosad is low in toxicity to people and other mammals. However, if it gets on your skin or in your eyes it can cause irritation and redness. In one study, 28 dogs were fed low to moderate doses of spinosad. One dog that received a moderate dose vomited. No effects related to spinosad were observed in the other dogs.

What happens to spinosad when it enters the body?

When eaten, spinosad is readily absorbed. Once inside it moves to many areas of the body and is broken down. The majority leaves the body in feces or urine within 1-2 days. Spinosad is absorbed poorly through skin contact.

Is spinosad likely to contribute to the development of cancer?

No. In multiple studies, animals were fed low to moderate amounts of spinosad in their diet for 1.5 to 2 years. No increased incidence of cancer was observed.Moreover, spinosad has not been found to alter or damage genes. As a result of these experiments, the EPA has classified spinosad as not likely to cause cancer.


Are children more sensitive to spinosad than adults?

Children may be especially sensitive to pesticides compared to adults. However, there are currently no data showing that children have increased sensitivity specifically to spinosad.

I remember and understand that instinct to protect your baby from anything that could possibly hurt it, and the world seems awash in attack vectors, but you will chuckle about this when the baby is older - and if you have a second baby you will be so much more lackadaisical, promise. 90% of parental anxiety is... not productive, it doesn't help the kid and it doesn't help you. I'd relax about this one, and let kitty back inside. :) Best of luck,
posted by smoke at 4:31 PM on May 29, 2019 [1 favorite]

If you truly come to the conclusion that this medicine will require you to keep the cat in the garage for a month, then PLEASE pick a different medication. That kind of isolation is just mean to the cat!
posted by mccxxiii at 6:56 PM on May 29, 2019 [1 favorite]

I don't agree with trying to convince you that Spinosad is safe for your newborn baby and/or cat. At first glance, it doesn't look like there is much research on the effect on humans, and the other dog studies were pretty short-term. Also, I quickly googled and found a study where Spinosad was possibility problematic for some rats. Ideally, the lifespan of a human (counting from infancy) will greatly exceed that of the other veterebrates studied, and long-term effects are unknown. I wouldn't roll the dice because my cat had fleas at the same time that I had a new baby.

I suspect there are many other options to dealing with the flea infestation. Is there someone who would be willing to keep your cat while it is being treated with the Spinosad? If fleas are anything like lice, they can be removed manually. Is your cat receptive to bathing and combing? There are several "lice ladies" in my area who will pluck each and every louse and nit from your head by hand using only their fingertips, a comb and lots of conditioner. Perhaps there is a cat version?

There are many, many things that you will be unfoundedly paranoid about as a new parent, but I don't believe that a flea killer that causes muscle spasms and then paralysis to invertebrates is one of them.

By the way, definitely, definitely vaccinate your baby.
posted by defreckled at 7:59 PM on May 29, 2019

Response by poster: Thanks for all the responses! I'll give that Infant Risk hotline a call.
posted by slidell at 12:25 PM on May 30, 2019