Newly Published Data in Parasites & Vectors Demonstrates the Fast Action and Long-Lasting Efficacy of BRAVECTO® (fluralaner) Chews for Dogs

BRAVECTO rapidly and consistently kills Ixodes scapularis ticks, a vector of the pathogen responsible for Lyme Disease, as compared to Simparica TRIO®

RAHWAY, N.J., February 2, 2024 – MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced the publication of a recent study demonstrating BRAVECTO® (fluralaner) Chews for Dogs had faster residual speed of kill compared to Simparica TRIO® against repeated infestations of Ixodes scapularis. All dogs administered BRAVECTO Chews were 100 percent tick-free at every 24-hour tick count. At no point were all dogs in the Simparica TRIO group free from ticks.

The study, “Comparison of the initial and residual speed of Ixodes scapularis kill on dogs treated with a single dose of BRAVECTO Chew (25 mg/kg fluralaner) or Simparica TRIO (1.2 mg/kg sarolaner, 24 µg/kg moxidectin, 5 mg/kg pyrantel)” is available at Parasites & Vectors.

“It’s important to kill ticks as quickly as possible given the longer a tick is able to feed uninterrupted, the greater the risk of a dog being infected with a tick-borne pathogen,” said Dorothy Normile, Veterinary Insights and Medical Affairs for MSD Animal Health. “This research conducted by Kansas State University allows veterinarians to make informed decisions when recommending tick control practices. In addition, it helps pet owners understand the importance of choosing a product that provides excellent and rapid activity against newly acquired ticks.”

The Ixodes scapularis species causes significant concern in certain regions of the world as the vector of disease-causing pathogens, such as Borrelia burgdorferi (the organism responsible for Lyme Disease) and Anaplasma phagocytophylum (the causative agent of anaplasmosis).1,2 Previous studies have shown that treatments that protect for a longer period can contribute to improved adherence to treatment recommendations. Long-term treatment not only helps ensure adequate protection against the various flea and tick species throughout the world but also simplifies the process for both pet owners and veterinarians. Per label, BRAVECTO Chews for Dogs effectively treats dogs infested with the Ixodes scapularis for up to 12 weeks after administration of a single dose.

The study, conducted by researchers at Kansas State University and sponsored by MSD Animal Health, revealed the differences in Ixodes scapularis kill between BRAVECTO Chews and Simparica TRIO. Both initially and 28 days after administration, a higher proportion of dogs were tick-free if given BRAVECTO Chews, when assessed 12 hours after a tick infestation. All dogs in the BRAVECTO Chews group were tick-free at every 24-hour tick count; however, there was no point in the study where all dogs in the Simparica TRIO group were tick-free.

To learn more about BRAVECTO and for safety information, visit:

About BRAVECTO® (fluralaner)

Since its introduction in 2014, BRAVECTO has provided longer-lasting flea and tick protection, with more than 300 million doses distributed in more than 100 countries. BRAVECTO is available in a variety of formulations, including products for both dogs and cats.

Providing pets with continuous flea and tick protection is essential – whether the pet goes outside or not. Contrary to popular belief among pet parents, fleas and ticks are not only active in the spring and summer months, but they are a year-round risk.

Fleas and ticks can easily infest dogs and cats. Ticks can spread serious diseases including rickettsiosis, anaplasmosis and borreliosis (Lyme disease), while fleas are the most common external parasite found on pets and can transmit bartonellosis (Cat Scratch disease) and tapeworms.

About MSD Animal Health

At MSD, known as Merck & Co., Inc., Rahway, N.J., USA in the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than a century, we’ve been at the forefront of research, bringing forward medicines, vaccines and innovative health solutions for the world’s most challenging diseases. MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is the global animal health business of MSD. Through its commitment to The Science of Healthier Animals®,MSD Animal Health offers veterinarians, farmers, producers, pet owners and governments one of the widest ranges of veterinary pharmaceuticals, vaccines and health management solutions and services as well as an extensive suite of connected technology that includes identification, traceability and monitoring products. MSD Animal Health is dedicated to preserving and improving the health, well-being and performance of animals and the people who care for them. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. MSD Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit and connect with us on LinkedIn and X (formerly Twitter).

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of the global outbreak of novel coronavirus disease (COVID-19); the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2022 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (


  1. Lavan R, Normile D, Husain I, Singh A, Armstrong R, Heaney K. An assessment of canine ectoparasiticide administration compliance in the USA. Parasites & Vectors. 2022 Dec;15(1):1-1.
  2. Lavan R, Armstrong R, Burgio F, Tunceli K. Duration of annual canine flea and tick protection provided by dog owners in Spain. Parasites & vectors. 2018 Dec;11:1-8