Merck Animal Health Reinforces Commitment to Help Protect U.S. Livestock from New World Screwworm Threat
June 4, 2026 7:16 pm EDT
Company underscores its ongoing commitment to strengthening cattle producer and veterinarian preparedness through collaboration, education and innovation
RAHWAY, N.J. June 4, 2026 — Merck Animal Health, known as MSD Animal Health outside the United States and Canada, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE: MRK), today reaffirmed its commitment to supporting the cattle industry’s response to the growing threat of New World screwworm following confirmation of the first case in U.S. cattle. The company underscored the continued need for industrywide collaboration to combat this devastating parasite. As a leader in livestock health, Merck 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 livestock industry.
Our commitment to collaboration and education
As part of its proactive response, Merck Animal Health recently hosted a New World screwworm symposium in San Antonio. Held April 22-24, the event brought together cattle producers and veterinarians from high-risk regions. Leading researchers, academic experts, government representatives and Merck Animal Health technical team members delivered programming focused on NWS preparedness, risk mitigation and coordinated strategies to help protect U.S. livestock.
“The U.S. cattle industry successfully eradicated New World screwworm in the past, and renewed vigilance and collaboration across the industry are essential to preventing and managing this evolving threat,” said Rick DeLuca, president of Merck Animal Health. “Merck Animal Health is committed to being a partner in that effort by providing innovative solutions to support veterinarian and producer preparedness.”
During the symposium, experts stressed the importance of coordinated, industrywide efforts to curb the spread and minimize risk. Because NWS affects all warm-blooded animals, preparedness and strong collaboration across stakeholders are critical. Key prevention strategies highlighted by industry leaders include:
- Daily observation of livestock and wildlife to detect wounds and potential infestations early
- Prompt reporting of suspected cases to enable rapid response
- A strong veterinarian relationship to support development of an NWS management plan
Our commitment to innovation
In December 2025, Merck Animal Health received conditional approval from the U.S. Food and Drug Administration for EXZOLT® CATTLE-CA1 (fluralaner topical solution), the first novel ectoparasiticide introduced for beef cattle in several decades. EXZOLT CATTLE-CA1 is a pour-on product for the prevention and treatment of infestations caused by New World screwworm larvae (myiasis). The product has been available in the United States since early spring 2026, with distribution focused on southern border states to help ensure access in regions at the highest risk of NWS outbreak.
“Innovation plays a critical role in how we respond to emerging threats like New World screwworm,” said Justin Welsh, executive director of livestock technical services, Merck Animal Health. “EXZOLT CATTLE-CA1 represents an entirely new drug class never before used in U.S. cattle. When paired with strong veterinary partnerships and proactive management, it gives the industry an important new tool to help protect cattle herds.”
Only EXZOLT CATTLE-CA1 brings a new active ingredient and drug class to the cattle industry, with no known resistance. It is the first and only topical product conditionally approved for NWS prevention and treatment and delivers the active ingredient fluralaner systemically against infestations. EXZOLT CATTLE-CA1 is approved for use in beef cattle 2 months of age and older and in replacement dairy heifers younger than 20 months. It is also conditionally approved for the treatment and control of cattle fever tick.
EXZOLT CATTLE-CA1 is available by prescription in 1-liter and 5-liter presentations. For more information about EXZOLT CATTLE-CA1, visit ExzoltCattle-CA1.com.
IMPORTANT SAFETY INFORMATION:
Conditionally approved by FDA pending a full demonstration of effectiveness under application number 141-617.
It is a violation of Federal law to use this product other than as directed in the labeling.
Not for use in humans. Keep out of reach of children. Accidental exposure may cause skin and eye irritation. Highly flammable. Keep away from heat, sparks, open flame or other sources of ignition. Use only for the prevention and treatment of infestations caused by New World screwworm (Cochliomyia hominivorax) larvae (myiasis) and treatment and control of cattle fever tick (Rhipicephalus microplus) in beef cattle 2 months of age and older and replacement dairy heifers less than 20 months of age. Not for use in bulls intended for breeding 1 year of age and older, dairy calves, and veal calves. Cattle must not be slaughtered for human consumption within 98 days of treatment. If cattle are continuously exposed to temperatures at or above 60°F after product administration, then cattle may be slaughtered for human consumption 44 days after treatment. Violative residues may result if cattle are exposed to temperatures below 60°F after administration and are slaughtered at 44 days. For complete safety information and product dosing instructions, refer to the product label.
About Merck Animal Health
Merck 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.merck-animal-health.com and connect with us on LinkedIn, Facebook, X (formerly Twitter) and Instagram.
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 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, 2025 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).
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