For many Americans, the arrival of autumn traditionally signals a reduction in problems caused by ticks and seasonal allergies. But changing weather patterns and longer pollen seasons are altering that pattern. As parasite and allergy exposure increasingly persists throughout the year, pet owners are facing more continuous needs in the parasiticide and dermatology segments of the multibillion-dollar pet health market.
Elanco Animal Health Incorporated says its pet health portfolio is benefiting from growing demand for preventive and wellness care. The company points to a shift toward what it describes as a year-round “tick and itch season,” along with changes in how consumers purchase pet health products through an increasingly diverse omnichannel market.
Elanco's global commercial execution and portfolio of new products have contributed to stronger year-over-year price performance quarter-to-date through July and August, with its U.S. Pet Health business leading the improvement.
“Elanco’s continued momentum, building on our strongest first half since our IPO, reflects the strength of our new innovation to increase the standard of care against these growing pet health threats,” said Jeff Simmons, President and CEO of Elanco. “It underscores the durability of the market and our commitment to our customers to deliver on their higher expectations for care. We are creating sustainable value for pet owners and the industry through our truly differentiated portfolio of innovation, driving market share and accelerating price gains in what we see as a responsible competitive backdrop.”
Tick and Allergy Seasons Are Becoming Less Seasonal
Milder weather is creating conditions that allow parasites to remain active for longer periods. Ticks can survive and reproduce in areas where prolonged freezing temperatures once limited their activity, while their geographic range is also expanding.
In summer 2026, tick-related emergency-room visits in the United States reached their highest level since the Centers for Disease Control and Prevention began monitoring the measure in 2017. Although visits generally fall during the summer as people become more aware of tick risks, CDC data show another increase during autumn. Ticks can remain active whenever temperatures stay above freezing.
Pollen exposure is following a similar pattern. Since 1970, the growing season and associated pollen exposure have increased in 87% of U.S. cities, with the most affected areas experiencing seasons that are roughly a month longer. Pollen concentrations have also risen by more than 20% since 1990.
Together, these developments are changing the traditional concept of a limited spring-and-summer parasite or allergy season.
Pets Are an Increasing Link Between Outdoor Exposure and the Home
The rise in tick-related health incidents is part of a broader trend associated with warmer winters and earlier springs. Ticks are becoming active sooner, remaining active later and appearing in locations where they were previously less common.
At the same time, pets have become increasingly integrated into family life and household routines. That creates a direct pathway through which environmental exposure can enter the home.
“One bite is all it takes, and the distance between environmental exposure and human contact is shortening,” said Bobby Modi, Executive Vice President, U.S. Pet Health at Elanco. “A pet that picks up a tick outdoors carries that risk directly into the home, often to the most vulnerable members of the family—children and older adults.”
Modi also emphasized the importance of rapid parasite control. “Speed of kill isn’t just a clinical metric; it’s a household safety requirement,” he said, adding that Elanco's products are designed to address these concerns while providing greater peace of mind for pet-owning households.
Elanco Targets Growth Across the Global Pet Health Market
As parasite and dermatology needs become less dependent on traditional seasons, Elanco is positioning its products across multiple purchasing channels. The company reported strong performance from both its U.S. and international Pet Health operations during the first half of 2026.
Organic constant-currency revenue increased 9% year over year in each business during the period. On a reported basis, growth was 9% in the U.S. and 15% internationally. Elanco attributed the performance in part to its broad parasiticide portfolio and expanding dermatology offering.
Market-share gains across major categories:
During the second quarter, Elanco's U.S. Pet Health business reported share gains in dermatology, parasiticides, osteoarthritis pain and vaccines. For the first six months of 2026, the company increased its overall U.S. market share, supported by newer products as well as improved stability in its established portfolio.
A more balanced parasiticide market:
The U.S. over-the-counter parasiticide market was approximately evenly distributed between the two halves of the year in 2025, with around 52% of sales occurring during the first six months and 48% during the remainder. Adoption of Credelio Quattro through veterinary clinics continued during July and August, with approximately 1,100 additional clinics added during the quarter-to-date period.
Growing use of home delivery:
Longer parasite seasons are also influencing purchasing behavior. Elanco reported that veterinary home-delivery sales grew at nearly twice the rate of in-clinic sales during the second quarter. Historically, the company says compliance has increased by about 50% when pet owners move to delivery programs, including automatic shipments.
Momentum in U.S. Pet Health:
Elanco's U.S. Pet Health operation accelerated during the second quarter, with the company maintaining its previously communicated expectation for continued growth during the second half of 2026. Price performance also strengthened during July and August.
International dermatology growth:
The international dermatology market expanded 9% during the first half of 2026, with Zenrelia contributing significantly to Elanco's performance. Growth for the product accelerated in Europe, where three JAK-1 products have been available for the longest period. Elanco reported that Zenrelia gained 10 percentage points of market share in Europe during the first half, which the company said was five times the gain of the competing entrant. Customer satisfaction was cited as a major contributor.
Improvement in the established portfolio:
Elanco also reported greater stability across its legacy products. The company said the base business has improved from mid-single- to high-single-digit declines during 2023–2024 to approximately low-single-digit changes around the current period, with further stabilization expected.
Innovation Remains Central to Elanco's Strategy
Simmons said the company's performance reflects contributions from new products, a more stable established portfolio and execution by its commercial teams.
“Elanco’s momentum is resilient, driven by our innovation, stabilized base business and the strong execution from the Elanco team,” Simmons said. He added that the expansion of the “tick and itch season” is increasing demand for products offering differentiated medical benefits, including broader parasite coverage and faster tick kill.
According to Elanco, these product attributes are helping address changing pet health needs while supporting continued market-share gains and pricing momentum as the company seeks to build long-term value for customers and shareholders.
Elanco Animal Health Incorporated says its pet health portfolio is benefiting from growing demand for preventive and wellness care. The company points to a shift toward what it describes as a year-round “tick and itch season,” along with changes in how consumers purchase pet health products through an increasingly diverse omnichannel market.
Elanco's global commercial execution and portfolio of new products have contributed to stronger year-over-year price performance quarter-to-date through July and August, with its U.S. Pet Health business leading the improvement.
“Elanco’s continued momentum, building on our strongest first half since our IPO, reflects the strength of our new innovation to increase the standard of care against these growing pet health threats,” said Jeff Simmons, President and CEO of Elanco. “It underscores the durability of the market and our commitment to our customers to deliver on their higher expectations for care. We are creating sustainable value for pet owners and the industry through our truly differentiated portfolio of innovation, driving market share and accelerating price gains in what we see as a responsible competitive backdrop.”
Tick and Allergy Seasons Are Becoming Less Seasonal
Milder weather is creating conditions that allow parasites to remain active for longer periods. Ticks can survive and reproduce in areas where prolonged freezing temperatures once limited their activity, while their geographic range is also expanding.
In summer 2026, tick-related emergency-room visits in the United States reached their highest level since the Centers for Disease Control and Prevention began monitoring the measure in 2017. Although visits generally fall during the summer as people become more aware of tick risks, CDC data show another increase during autumn. Ticks can remain active whenever temperatures stay above freezing.
Pollen exposure is following a similar pattern. Since 1970, the growing season and associated pollen exposure have increased in 87% of U.S. cities, with the most affected areas experiencing seasons that are roughly a month longer. Pollen concentrations have also risen by more than 20% since 1990.
Together, these developments are changing the traditional concept of a limited spring-and-summer parasite or allergy season.
Pets Are an Increasing Link Between Outdoor Exposure and the Home
The rise in tick-related health incidents is part of a broader trend associated with warmer winters and earlier springs. Ticks are becoming active sooner, remaining active later and appearing in locations where they were previously less common.
At the same time, pets have become increasingly integrated into family life and household routines. That creates a direct pathway through which environmental exposure can enter the home.
“One bite is all it takes, and the distance between environmental exposure and human contact is shortening,” said Bobby Modi, Executive Vice President, U.S. Pet Health at Elanco. “A pet that picks up a tick outdoors carries that risk directly into the home, often to the most vulnerable members of the family—children and older adults.”
Modi also emphasized the importance of rapid parasite control. “Speed of kill isn’t just a clinical metric; it’s a household safety requirement,” he said, adding that Elanco's products are designed to address these concerns while providing greater peace of mind for pet-owning households.
Elanco Targets Growth Across the Global Pet Health Market
As parasite and dermatology needs become less dependent on traditional seasons, Elanco is positioning its products across multiple purchasing channels. The company reported strong performance from both its U.S. and international Pet Health operations during the first half of 2026.
Organic constant-currency revenue increased 9% year over year in each business during the period. On a reported basis, growth was 9% in the U.S. and 15% internationally. Elanco attributed the performance in part to its broad parasiticide portfolio and expanding dermatology offering.
Market-share gains across major categories:
During the second quarter, Elanco's U.S. Pet Health business reported share gains in dermatology, parasiticides, osteoarthritis pain and vaccines. For the first six months of 2026, the company increased its overall U.S. market share, supported by newer products as well as improved stability in its established portfolio.
A more balanced parasiticide market:
The U.S. over-the-counter parasiticide market was approximately evenly distributed between the two halves of the year in 2025, with around 52% of sales occurring during the first six months and 48% during the remainder. Adoption of Credelio Quattro through veterinary clinics continued during July and August, with approximately 1,100 additional clinics added during the quarter-to-date period.
Growing use of home delivery:
Longer parasite seasons are also influencing purchasing behavior. Elanco reported that veterinary home-delivery sales grew at nearly twice the rate of in-clinic sales during the second quarter. Historically, the company says compliance has increased by about 50% when pet owners move to delivery programs, including automatic shipments.
Momentum in U.S. Pet Health:
Elanco's U.S. Pet Health operation accelerated during the second quarter, with the company maintaining its previously communicated expectation for continued growth during the second half of 2026. Price performance also strengthened during July and August.
International dermatology growth:
The international dermatology market expanded 9% during the first half of 2026, with Zenrelia contributing significantly to Elanco's performance. Growth for the product accelerated in Europe, where three JAK-1 products have been available for the longest period. Elanco reported that Zenrelia gained 10 percentage points of market share in Europe during the first half, which the company said was five times the gain of the competing entrant. Customer satisfaction was cited as a major contributor.
Improvement in the established portfolio:
Elanco also reported greater stability across its legacy products. The company said the base business has improved from mid-single- to high-single-digit declines during 2023–2024 to approximately low-single-digit changes around the current period, with further stabilization expected.
Innovation Remains Central to Elanco's Strategy
Simmons said the company's performance reflects contributions from new products, a more stable established portfolio and execution by its commercial teams.
“Elanco’s momentum is resilient, driven by our innovation, stabilized base business and the strong execution from the Elanco team,” Simmons said. He added that the expansion of the “tick and itch season” is increasing demand for products offering differentiated medical benefits, including broader parasite coverage and faster tick kill.
According to Elanco, these product attributes are helping address changing pet health needs while supporting continued market-share gains and pricing momentum as the company seeks to build long-term value for customers and shareholders.