Ivermectin Effective Against New World Screwworms Larval Stages (L1, L2, L3)
As New World screwworms emerge in Texas and New Mexico, the evidence suggests ivermectin may be one of the most effective defenses in both animals and humans.
Nicolas Hulscher, MPH
Jun 08, 2026
FDA Issues Emergency Use Authorization for Over-the-Counter Injectable Drug to Prevent New World Screwworm in Cattle
February 5, 2026
Today the U.S. Food and Drug Administration issued an Emergency Use Authorization (EUA) for Ivomec (ivermectin) injectable solution against New World screwworm (NWS). The agency has concluded that based on the scientific evidence available, it is reasonable to believe that Ivomec may be effective for the prevention of infestations caused by NWS larvae (myiasis) in cattle when administered within 24 hours of birth, at the time of castration, or when a wound appears, and the known and potential benefits of the product outweigh its known and potential risks.
Ivomec is not for use in female dairy cattle producing milk for human consumption and calves that will be processed for veal. The slaughter withdrawal period for cattle is 35 days.
This EUA will be effective until it is revoked or the HHS Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.
Ivomec is available over the counter without a prescription. Producers are responsible for using Ivomec in accordance with the product labeling and fact sheet.
To reduce the risk of antiparasitic resistance and preserve drug effectiveness against both NWS and other parasites, producers are encouraged to use antiparasitic drugs like Ivomec only when medically necessary and as part of a comprehensive parasite management strategy.
The FDA has previously approved Ivomec to treat and control other parasites in cattle, swine, reindeer and American bison.
Ivomec is sponsored by Boehringer Ingelheim Animal Health USA, Inc. based in Duluth, Georgia.
Related Information
Freedom of Information Summary: Ivomec (EUA 006689)
Letter of Authorization: Ivomec (EUA 006689)
Fact Sheet: Emergency Use Authorization of Ivomec (ivermectin) Injection
Ranchers already use ivomec to deworm their cattle, in spring and fall. Using that as well as closer attention to livestock and we should be just fine. We didn’t have ivermectin the last time the screwworm was in the US cattle supply (there was a short outbreak in 2016 in Florida in the deer population and it was gone by 2017).
Edit: Anyone screeching about this topic is just fearmongering. It only spreads through open sores and navels that are fresh in newborn calves. Ranchers know how to deal with this because we already deal with open sores and doctor navels in newborn calves.
Be aware that neither ivermectin nor fenben cover ALL parasites individually & that many recommend alternating between the two for full coverage. They say you're not supposed to take both simultaneously as that can cause liver and kidney damage. Be sure to do your homework...
Yeah, like my cat with hyperthyroid whose meds for that helped to destroy her kidneys. Can we please move on to the part where we don't need pharmaceutical anything?
Ivermectin Effective Against New World Screwworms Larval Stages (L1, L2, L3) As New World screwworms emerge in Texas and New Mexico, the evidence suggests ivermectin may be one of the most effective defenses in both animals and humans. Nicolas Hulscher, MPH Jun 08, 2026
https://www.thefocalpoints.com/p/ivermectin-kills-new-world-screwworms
Great post! Thanks chick! 👏
I found this also:
FDA Issues Emergency Use Authorization for Over-the-Counter Injectable Drug to Prevent New World Screwworm in Cattle
February 5, 2026
Today the U.S. Food and Drug Administration issued an Emergency Use Authorization (EUA) for Ivomec (ivermectin) injectable solution against New World screwworm (NWS). The agency has concluded that based on the scientific evidence available, it is reasonable to believe that Ivomec may be effective for the prevention of infestations caused by NWS larvae (myiasis) in cattle when administered within 24 hours of birth, at the time of castration, or when a wound appears, and the known and potential benefits of the product outweigh its known and potential risks.
Ivomec is not for use in female dairy cattle producing milk for human consumption and calves that will be processed for veal. The slaughter withdrawal period for cattle is 35 days.
This EUA will be effective until it is revoked or the HHS Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.
Ivomec is available over the counter without a prescription. Producers are responsible for using Ivomec in accordance with the product labeling and fact sheet.
To reduce the risk of antiparasitic resistance and preserve drug effectiveness against both NWS and other parasites, producers are encouraged to use antiparasitic drugs like Ivomec only when medically necessary and as part of a comprehensive parasite management strategy.
The FDA has previously approved Ivomec to treat and control other parasites in cattle, swine, reindeer and American bison.
Ivomec is sponsored by Boehringer Ingelheim Animal Health USA, Inc. based in Duluth, Georgia.
Related Information
SOURCE: https://www.fda.gov/animal-veterinary/cvm-updates/fda-issues-emergency-use-authorization-over-counter-injectable-drug-prevent-new-world-screwworm
Ranchers already use ivomec to deworm their cattle, in spring and fall. Using that as well as closer attention to livestock and we should be just fine. We didn’t have ivermectin the last time the screwworm was in the US cattle supply (there was a short outbreak in 2016 in Florida in the deer population and it was gone by 2017). Edit: Anyone screeching about this topic is just fearmongering. It only spreads through open sores and navels that are fresh in newborn calves. Ranchers know how to deal with this because we already deal with open sores and doctor navels in newborn calves.
Be aware that neither ivermectin nor fenben cover ALL parasites individually & that many recommend alternating between the two for full coverage. They say you're not supposed to take both simultaneously as that can cause liver and kidney damage. Be sure to do your homework...
Found this in the wild
Yeah, like my cat with hyperthyroid whose meds for that helped to destroy her kidneys. Can we please move on to the part where we don't need pharmaceutical anything?
Without a doubt, we will ALL inevitably reach that part when our number is called...
u/#catdance
My vision is more like, in our lifetime...
It's a personal choice - you do the best you can.
It's a LOT of work eating clean & nutrient dense foods consumed on time, at the right time of day etc.
It can be done, but it takes dedication & preparing and packing your own food of you leave home on a trip etc.
The HERD will never get on track in our lifetime - It's a very personal, individual thing.
As far as doctors and care go, you have to seek out alternatives. I haven't gone to a medical doctor for anything in 35 years.
Again, not easy, not popular, but doable. Learn applied kinesiology and up your diagnostic ability yourself.
Shits awesome A dab a day for 5 days 1 tube is short for my weight but works just fine!