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’s true that flea, tick and mosquito activity spikes during the spring and summer, these pests can cause health issues for your pet year-round.

Though they pose a much lower risk during colder winter months, by the time spring rolls around, parasites like fleas, ticks and mosquitoes may already be in full bloom. Not only can these parasites impact your pet’s health by stealing their nutrients, but they can also pass on diseases like Lyme disease or heartworms.

Certain areas of the U.S. face higher disease and infection risks than others, and at different times throughout the year.

Flea Season Has No Off-season 

Though fleas may be less prevalent during colder months, there is technically 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 family pet, fleas will make themselves at home no matter the time of year.

Map of the U.S. shows where and when fleas are most active.

Content supplied by American Kennel Club: “What’s Your State’s Flea-and-Tick Season?" 1

When Is Flea Season?

Fleas tend to be more active during warmer months. They favor humid weather and temperatures from 60-75°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.

However, even if the outside temperature is inhospitable to fleas, if you keep your house at a temperature around or higher than 60-69°F, your indoor pet is at risk of fleas.

Where Are Fleas Found? 

Fleas are found in places where you and your pets spend the most time, such as pet beds, furniture and carpets. Hitchhiking fleas can hop a ride on people and pets as they move in and out of your house. And once on a pet, fleas lay eggs, which can quickly develop into an infestation.

What Can You Do to Protect against Fleas?

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.

Ticks Are Always in Season 

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.

Map of the U.S. shows tick presence by brown dog tick, American dog tick, deer tick and Lone Star tick.

Content supplied by Kansas State University CVM ITC. M.W. Dryden, DVM, Ph.D., and P.A. Payne, DVM, Ph.D.; 2016.

When Is Tick Season?

Tick season typically runs from mid-spring through late fall. Peak tick season varies depending on where you live in the U.S. and the types of ticks most prevalent in your area.

Where Are Ticks Found?

Ticks hang out where they can easily feed on live animals, usually wooded areas and grassy spots like your own backyard, a park, on hiking trails or in the woods or fields as well. Ticks cling to tall blades of grass or lower-hanging foliage until they can attach themselves to passing animals.

Tick Disease Risks: Lyme Disease, Ehrlichiosis and Anaplasmosis

Common diseases spread by ticks vary based on season and location. Ticks are known to spread dangerous diseases like Lyme disease.

Lyme disease is a fairly common disease in dogs and 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).

Map of the U.S. forecasts Lyme disease population density in 2019.

Ticks can also spread 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.

Map of the U.S. forecasts ehrlichiosis population density in 2019.

Ticks can also spread 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.

 Map of the U.S. forecasts anaplasmosis population density in 2019.

Anaplasmosis requires a vet diagnosis and can be treated with antibiotics. Check the CAPC maps for tick-borne disease prevalence in cats and dogs before venturing out, and take further steps to keep your pets protected from ticks.

What Can You Do to Protect against Ticks? 

Because ticks love long grass and low-hanging bushes, keep your yard mowed and your foliage trimmed. 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 daily tick checks when tick activity or your pet’s outdoor access is higher.

Find prevention products at local or online pet specialty retailers, and then remember to apply them properly and routinely.

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 map above or visit the Center for Disease Control (CDC) 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, there are several effective heartworm prevention products available for dogs and cats. Additionally, there are a few products for dogs that kill mosquitoes through contact, often before they have a chance to take a blood meal.

When Is Mosquito Season?

Mosquitoes thrive in 75-80°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.

Map of the U.S. forecasts heartworm population density in 2019.

Heartworms and mosquitoes go hand in hand. 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?

Mosquitoes require stagnant water to breed, so 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.

CAPC identified the top 10 cities during February 20192  that have had the highest increase of heartworm-positive tests in dogs:

  1. Salt Lake City, Utah
  2. Alexandria, Virginia
  3. Riverside, California
  4. Topeka, Kansas
  5. El Paso, Texas
  6. Paterson, New Jersey
  7. Chesapeake, Virginia
  8. Reno, Nevada
  9. Modesto, California
  10. Boise, Idaho

These cities are spread throughout the United States, which further illustrates the prevalence of heartworm-transmitting mosquitoes across the country.

What Can You Do to Protect Your Pet from Mosquitoes?

Because mosquitoes can transmit deadly diseases, it is important to eliminate or avoid areas where they like to breed. Fortunately for our pets, there are a number of highly effective and safe heartworm disease prevention products available.

It can take up to six months before a test can detect a heartworm infection, which means that even 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. There are also several products for dogs that offer protection from mosquitoes by killing them through contact. Products that kill through contact do not require mosquitoes to bite your pet to die.

Prevention Season Starts Now 

Bayer 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.

Related articles:

4 Common Flea Diseases in Dogs

Understanding Tick Diseases in Dogs

Heartworms in Dogs

Mosquito Diseases in Dogs

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Date of review May 2021

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