Mexico’s SADER Approves MSD Animal Health’s BRAVECTO® (Fluralaner) Chew Tableta Masticable (Chew) for the Treatment of New World Screwworm (Cochliomyia hominivorax) in Dogs
August 24, 2026
BRAVECTO Eliminated 100% of Live Screwworm Larvae in Canines Within 24 Hours in Field Study, Demonstrating Powerful Efficacy and Strong Safety Profile
RAHWAY, N.J., August 24, 2026 – MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced the Secretaria de Agricultura y Desarrollo Rural (SADER) granted approval for BRAVECTO® (Fluralaner) Chew Tableta Masticable (Chew) for the treatment of infestations caused by New World screwworm (Cochliomyia hominivorax) larvae (myiasis).
Cochliomyia hominivorax is an obligate biotrophic parasite endemic to Neotropical regions, causing severe traumatic myiasis in mammals, which can lead to significant morbidity and mortality if left untreated. The resurgence of the New World screwworm is one of the main challenges for animal health in Mexico. According to data from the National Service for Agri-Food Health, Safety, and Quality (SENASICA), from November 2024 through July 2026, 37,236 cases have been recorded in different animal species, of which 8,518 correspond to dogs, positioning them as the second most affected species by this disease.
“New World screwworm requires immediate attention. A timely evaluation of any wound and early intervention by the Veterinarian can make an important difference in the dog’s clinical course. Today, in addition to strengthening surveillance, it is essential to have tools supported by scientific evidence that help guide clinical decision-making,” said Alejandro Sánchez, veterinarian and technical manager, Companion Animals Business Unit, MSD Animal Health, Mexico.
In Mexico, which is home to nearly 43.8 million dogs and where 71.7% of households have at least one pet, strengthening prevention, timely diagnosis, and access to therapeutic tools is becoming increasingly important to protect the health and well-being of companion animals.
“Innovation has the greatest impact when it responds to the needs that veterinarians face in their daily practice. This new indication represents a therapeutic option supported by scientific evidence that helps strengthen the management of the screwworm in dogs and reflects MSD Animal Health’s ongoing commitment to developing solutions for emerging animal health challenges,” added Alejandro Sánchez.
MSD Animal Health is actively following all the processes set by the regulatory authorities in other countries to gain market authorization for this product against New World screwworm to control the spread of the disease and protect dogs.
Clinical Data Reinforces Strong Safety and Efficacy Profile
To evaluate a systemic alternative, researchers conducted a clinical study on 15 naturally infested dogs across endemic regions in Brazil. The study found that 100% of the treated dogs exhibited complete clearance of live larvae from the lesions within 24 hours post-administration of a single oral dose of BRAVECTO. The treatment achieved a 94.36% overall larvicidal efficacy, accounting for both larvae neutralized within the lesion and those expelled. While a fraction of larvae were expelled alive, none successfully pupated or emerged as adult flies (0% emergence rate). The oral treatment was well-tolerated across the study cohort, with no adverse events recorded.
Call to Action for Pet Owners
Given the presence of screwworm cases in different regions of the country, MSD Animal Health in Mexico recommends:
-Maintain a comprehensive parasite prevention and control program by following your Veterinarian’s recommendations.
-Go to the veterinarian immediately if there are wounds with discharge, foul odor, swelling, or suspected larvae.
-Periodically check your dogs’ skin and coat, especially if they spend time outdoors.
-Address immediately any wound, cut, or injury, no matter how small it may seem.
-Avoid self-medicating or trying to remove the larvae without professional supervision.
The resurgence of the screwworm serves as a reminder that prevention, surveillance, and scientific innovation are essential to protecting the health of companion animals. Through research and the development of new therapeutic alternatives, MSD Animal Health in Mexico reaffirms its commitment to veterinarians to respond to present and future animal health challenges, as well as to the well-being of pets and the families who live with them.
References:
1. National Service of Health, Food Safety, and Agri-Food Quality. (July 2026). Spread of the cattle screwworm in Mexico. Government of Mexico. https://www.gob.mx/cms/uploads/attachment/file/1091856/AVANCE_GBG_12_paginas-compressed.pdf
2. National Institute of Statistics and Geography. (2026). National Self-Reported Well-Being Survey (ENBIARE) 2025. https://www.inegi.org.mx/programas/enbiare/2025/
Our New World Screwworm Commitment
As a leader in animal health, MSD Animal Health has been at the forefront of developing innovative medicines for the prevention and treatment of NWS, facilitating information sharing and dialogue, and providing educational resources for the industry.
About BRAVECTO®
Since its introduction in 2014, BRAVECTO has provided longer-lasting flea and tick protection, with more than 450 million doses distributed in 100 countries over a decade. BRAVECTO is available in a variety of formulations, including products for both dogs and cats. The flea lifecycle can last as long as 12 weeks, and monthly treatments may leave gaps in protection. Providing pets with continuous flea and tick protection is essential – whether the pet goes outside or not. Contrary to popular belief among pet owners, fleas and ticks are not only active in the spring and summer months and are a year-round risk. Fleas and ticks can easily latch onto dogs and cats and can spread serious diseases. Fleas are the most common external parasite found on pets. BRAVECTO products are only available through licensed veterinarians.
About MSD Animal Health
MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is a global animal health business committed to The Science of Healthier Animals™. For more than 130 years, we have pioneered groundbreaking science. Today, we are driven by continuous innovation to develop breakthrough medicines, vaccines and technology. Rooted in direct experience on the farm and in the clinic, we work hand in hand with our customers every step of the way. Our singular focus is to empower those who care for animals, helping them manage their vital responsibility with confidence. Because when it comes to animal health, no one sees it like we do. For more information, visit www.msd-animal-health.com and connect with us on LinkedIn, Facebook, Instagram and X (formerly Twitter).
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