Let’s dive into why year-round parasite control is crucial and explore how best to protect your pet and your household.

Health risks parasites pose to pets

Parasites affect more than just comfort—they can cause serious, sometimes life-threatening disease in pets and pose risks to people. Common culprits include:

• Fleas — These tiny blood-sucking parasites are more than a nuisance—they cause relentless itching and discomfort for pets affected by flea bite dermatitis, which can lead to severe skin inflammation, hair loss, and secondary infections. Fleas can also carry tapeworms, which pets may ingest while grooming, leading to intestinal infections. In addition, young, small, or compromised pets can develop anemia from a severe flea infestation.
• Ticks — Ticks that attach to your pet can transmit several dangerous diseases, including Lyme disease, ehrlichiosis, Rocky Mountain spotted fever, and anaplasmosis. While feeding, ticks can also release a toxin that causes paralysis.
• Heartworms — Heartworms, which are transmitted to pets by mosquitoes, cause potentially fatal effects. Once inside the body, heartworm larvae mature and settle in the heart, lungs, and blood vessels, causing progressive damage. Infected pets may initially show no signs, but the growing worms can cause coughing, fatigue, weight loss, and difficulty breathing. Advanced heartworm disease can cause heart failure, organ damage, and death.
• Intestinal parasites — Intestinal worms, such as roundworms, hookworms, whipworms, and tapeworms, pose considerable health risks for pets. These parasites feed on nutrients or blood in the digestive tract, leading to diarrhea, vomiting, and weight loss. In severe cases, especially in young or weak pets, intestinal worms can cause anemia, malnutrition, and intestinal blockages. In addition, some worms, such as roundworms and hookworms, can be spread to humans.

Why pets need year-round parasite prevention

Parasites don’t follow calendars, and modern living conditions allow many species to survive well beyond traditional “parasite seasons.” While many parasites are more active during warmer months, they can pose a threat year-round. Considerations include:

• Unpredictable weather patterns — Unpredictable weather patterns, including warmer winters and fluctuating seasonal temperatures, allow  parasites to remain active year-round.
• Indoor environments — When temperatures drop, your home provides parasites with a warm, welcoming environment. Fleas can latch onto pets or people and enter your home to survive comfortably in carpets, upholstery, and bedding. Ticks can also hitch a ride indoors and thrive in a climate-controlled environment.
• Parasitic life cycles — Many parasites’ life cycles allow them to lie dormant for months, only to re-emerge when conditions are right. For example, roundworm and hookworm eggs often remain dormant in soil, water, and organic material until conditions are favorable.

Common myths about parasite prevention

Misconceptions about parasites can leave pets unprotected. Common myths include:

• I don’t need to treat my pet for parasites in the winter — Fact: Many parasites can thrive indoors and remain dormant during colder periods. Year-round parasite prevention is crucial to ensure protection.
• Indoor pets don’t need parasite prevention — Fact: Even pets who never go outside are at risk. Parasites such as fleas and ticks can be carried inside on clothing, and mosquitoes can find their way inside, putting indoor pets at risk.
• Natural remedies are sufficient — Fact: While some natural remedies may offer limited protection, they are not effective against all parasites. Veterinary-approved preventives are specifically designed to target parasites safely and effectively.

Tips for providing year-round parasite prevention for your pet

Pet owners have numerous options when choosing the best product to protect their pet from parasites. Our tips include:

• Consult your veterinarian — Each pet’s needs are different, and many options, including oral medications, topical treatments, and injectables, are available. Your veterinarian can recommend the most effective and convenient option for your pet based on their age, health, lifestyle, and any specific regional risks. Routine veterinary visits play an important role in parasite prevention, as your veterinarian can assess risk factors and recommend appropriate protection throughout your pet’s life.
• Stick to a schedule — Prevention must be consistent to be most effective. Set a reminder each month to apply or administer your pet’s medication. Some products offer all-in-one protection, while others may target specific parasites, so follow your veterinarian’s recommendations.

Year-round parasite prevention is a vital part of responsible pet care, protecting your pet’s health and comfort, while reducing risks your home and family. Contact your AAHA-accredited veterinarian to determine the best prevention plan for your pet’s age, lifestyle, and health needs.

Reviewed by AAHA Veterinarians

Date Updated: December 16, 2025