Flea, Tick and Mosquito Risk Maps: Is Your Pet at Risk?

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Flea, tick and mosquito seasons vary by area.

Woman with white hair wearing a winter coat hiking with her two dogs in the woods.

While it may seem like parasite activity spikes during the spring and summer, data shows that fleas, ticks and mosquitoes can cause health issues for your pet year-round. Not only can these parasites impact your pet’s health by stealing their nutrients; they can also pass on diseases like Lyme disease and heartworms.

Certain areas of the U.S. face higher disease and infection risks than others, and at different times throughout the year. Protecting your pet from fleas, ticks and mosquitoes starts with prevention and education. Understanding the threat these pests pose can help you keep your pets from unnecessary exposure.

Flea Season Has No Off-Season

It’s important for pet owners to stay alert for signs of infection and infestation, no matter what the weather is like. Though fleas may be less prevalent during colder months, there is no season in which your pet is not at risk of contracting fleas. As long as they have a warm host to live on, like your dog or cat, fleas will make themselves at home.

When Is Flea Season?

As temperatures rise, owners should be especially vigilant. Fleas tend to be more active during warmer months. They favor humid weather and temperatures from 60 to 75°F — which can be as early as late February in some parts of the U.S. and during a fall second season throughout the country.

Even if the outside temperature is inhospitable to fleas, your house’s indoor temperature will probably still be around or higher than 60 to 69°F, so your indoor pet is still at risk of hosting fleas. This means year-round risk, no matter where you live.

Where Are Fleas Found?

The most likely place you’ll find fleas is on your pet. However, your environment may be infested with the other, microscopic lifestages of the flea: eggs, larvae and pupae. These environmental stages of the flea life cycle tend to be invisible to the naked eye.  

When checking your pet for fleas, make sure to check your surroundings, too. Fleas may be found in places where you and your pets spend the most time, such as pet beds, furniture and carpets. Hitchhiking fleas can hop on people and pets as they move in and out of your home. Once they’re on a pet, fleas lay eggs, which can quickly develop into an environmental infestation.

What Can You Do to Protect against Fleas?

Although your pet may be the main host to fleas, these tiny pests can transfer to other surfaces, too. Wash bedding and vacuum floors and furniture regularly to help keep fleas from taking up residence in your home. Another great way to help prevent an infestation on your pet or in your home is to routinely use flea prevention products. You can find many effective products that fit your lifestyle at local and online pet-specialty retailers. Talk to your veterinarian to discuss all your options.

Ticks Are Always in Season

Like fleas, ticks don’t take time off. On their own, ticks live and breed in temperatures above 40°F. Some tick species can even be active all year long, regardless of temperature. Ticks transmit a variety of harmful diseases that affect pets and people alike, making year-round prevention essential.

When Is Peak Tick Season?

It’s always important for owners to keep an eye out for ticks, on humans and pets. Peak tick season varies depending on where you live in the U.S. and the types of ticks most prevalent in your area. 

Heat map of USA forecasting the prevalence of lyme disease.

Source: CAPC 2022 Annual Pet Parasite Forecasts 2022 (v1.0)

Where Are Ticks Found?

Many pets and their owners live in or near ideal tick environments, making it hard to avoid them entirely. Ticks hang out where they can easily feed on live animals, usually wooded areas and grassy spots like your backyard, a park, on hiking trails or in wooded areas or fields. Ticks cling to tall blades of grass or lower-hanging foliage until they can attach themselves to passing animals.

Avoiding exposure to ticks may not be possible for many pet owners, which is why preventive measures are crucial; exposure to a tick bite may mean exposure to disease.

Tick Disease Risks: Lyme Disease, Ehrlichiosis and Anaplasmosis

Common diseases spread by ticks vary based on season and location. Although the tick bite alone may not be dangerous, the potential infection or disease spread from it can be.

Ticks are known to spread dangerous diseases like Lyme disease, a fairly common disease in dogs. It is typically found in the Northeastern U.S. and Upper Midwestern U.S., where it is transmitted by the blacklegged tick (Ixodes scapularis), as well as along the Pacific coast, where it is transmitted by the western blacklegged tick (Ixodes pacificus).

Another dangerous infection spread by ticks is ehrlichiosis, a bacterial disease transmitted to dogs by the brown dog tick and American dog tick. Found throughout the U.S., the brown dog tick typically resides in warmer climates, but is also commonly found indoors.

Anaplasmosis is also spread by ticks and requires a vet diagnosis and treatment with antibiotics. If you want to venture out with your pet, check the CAPC maps for tick-borne disease prevalence in cats and dogs before you go to get a better understanding of what risks may pose a threat to your pet.

Keeping your pet safe from the dangers of ticks doesn’t have to start at the first signs of infection. Many owners choose preventive measures to decrease their pet’s chance of hosting ticks.

What Can You Do to Protect against Ticks?

It may be difficult or even impossible for pet owners to avoid exposure to ticks entirely. Because ticks love long grass and low-hanging bushes, keep your yard mowed and your foliage trimmed. It may also help to treat your yard with products that kill ticks in and around your home, deck and patio. Ticks can be found in urban areas as well, commonly in planters, trees and parks. Check your pet for ticks on a regular basis and get in the habit of doing personal daily tick checks, too — especially in seasons when tick activity or your pet’s outdoor access is higher.

Pet owners should also talk to their vet about prevention products available from the veterinarian, or at local or online pet-specialty retailers. These products can be applied routinely to protect your pet year-round, when used correctly.

For an estimate of where multiple species of ticks and their numbers may be highest in your area, look for your state on the tick-borne disease alert map to get frequent updates on tick activity.

Mosquitoes Are More Common During the Warmer Months

Unlike fleas and ticks, mosquitoes are temperature-sensitive and have more of a traditional season throughout most of the U.S. Other than the irritation their bites cause, the main concern with mosquitoes is their ability to transmit heartworms, leading to a potentially fatal disease for your dog or cat.

Luckily, several effective heartworm-prevention products are available for dogs and cats. Additionally, a few products for dogs kill mosquitoes through contact, often before they have a chance to feed.

Heat map of USA forecasting the prevalence of heartworm.

Source: CAPC 2022 Annual Pet Parasite Forecasts 2022 (v1.0) 

When Is Mosquito Season?

Mosquitoes thrive in 75 to 80°F weather and aren’t as active when temperatures drop. Traditionally, that means most of the U.S. sees an increase in mosquito populations beginning in May, with heightened activity well into August.

However, just as with ticks and fleas, there is no set mosquito season, as these insects can survive throughout all 12 months of the year. Even in colder climates and seasons, the slightest increase in temperature can impact the mosquito life cycle, putting your pets at risk. It is extremely difficult to avoid exposure to mosquitoes entirely, so many dog owners opt for preventive measures to decrease their dog’s chance of contracting mosquito-borne illnesses.

Although not every mosquito bite will be dangerous, there is still a risk of disease — like the potential spread of heartworm. To keep your pet safe, it’s important to stay educated on which seasons carry higher risk and disease prevalence in your area.

For a better idea of where mosquitoes are found and affect dogs, look for your state on the forecasted heartworm disease prevalence map above, or visit the Companion Animal Parasite Council (CAPC) Parasite Prevalence Map to learn more about where parasites are commonly found and which disease threats have been reported in which areas.*

*This information changes frequently as more cases are diagnosed.

Where Are Mosquitoes Found?

A lot of us are familiar with these annoying pests, especially during warmer seasons. Mosquitoes thrive in warmth and require stagnant water to breed. Areas with puddles, storm drains, water troughs, birdbaths or any kind of container that can collect water are potential breeding grounds for mosquitoes.

When ready to feed, mosquitoes are attracted to people and animals, sensing a meal from as far as 65 feet away. Small and quick, they easily find their victims indoors and outdoors. Many pets and humans have a hard time avoiding mosquitoes entirely; that’s why it’s important to protect your pet with a preventive regimen and stay educated on your area’s risk.

Multiple factors contribute to an area’s mosquito population and disease prevalence, so it’s not enough to only consider your location’s season or climate when determining risk. The CAPC identifies high-risk areas every year, which are widely spread throughout the United States, further illustrating the prevalence of heartworm-transmitting mosquitoes across the country. In 2022, the CAPC has reported an especially high risk for those located in the Mississippi River valley and surrounding areas.

What Can You Do to Protect Your Pet from Mosquitoes?

Mosquitoes can transmit deadly diseases, so it is important to eliminate or avoid areas where they like to breed, when possible. Follow these tips to help prevent your dog or cat from being bitten by mosquitoes:

  1. Stay indoors at dawn and dusk, when mosquitoes tend to be most active.
  2. Avoid spending time near stagnant water, including improperly drained areas of your yard, kiddie pools, dog bowls or empty flower pots. Consider treating your yard with a mosquito-repelling spray.
  3. Keep mosquitoes out of your home. Repair or replace tears in window or door screens, and look for openings where mosquitoes could buzz in.
  4. Apply a monthly spot-on treatment to help kill and repel mosquitoes from your pet. Products like K9 Advantix® II for dogs offer protection from mosquitoes by killing them through contact. K9 Advantix® II also repels fleas and ticks, so these year-round pests don’t have to bite your dog to die. (Keep in mind that K9 Advantix® II is not a substitute for a prescribed heartworm preventative.)

Protecting Your Pet from Heartworm

If you and your pet live somewhere with a large mosquito population, ask your veterinarian about prescribing a heartworm disease prevention product.

When using preventive measures, consistency is key. It can take six months or more before a test can detect a heartworm infection, which means that missing just one monthly treatment can put your dog at risk. Speak with your veterinarian about finding the right one for your dog or cat.

Prevention Season Starts Now

As pet owners, we can’t always ensure our dogs and cats will avoid exposure to risks like mosquitoes, ticks and fleas. Especially if your pet spends a lot of time outside or in high-risk areas, it’s important to stay up to date on local statistics and keep your pet on a consistent preventive regimen to protect against infection. Elanco Animal Health offers a wide range of effective flea, tick and mosquito prevention and treatment products, as well as heartworm prevention products.  Find them at pet specialty stores and veterinarian offices.

© 2023 Elanco or its affiliates. K9 Advantix, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates. 

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Date of review December 2022

© 2023 Elanco or its affiliates