Pet Parasites in the Midwest: A Regional Overview of Species and Risks

Reviewed by Brittany Kleszynski, DVM on 02/23/2024. Published on 02/23/2024

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As pet parents, we’re used to routine wellness check-ups and questions about our pets’ parasite medication schedules. Maybe your vet has even suggested taking home a collection kit for fecal parasite testing. It might all seem a bit over-the-top. But when was the last time you checked in on the latest parasite trends affecting pets in your area?

The Midwest is home to the sprawling plains, the shores of the Great Lakes, and the foothills of the Ozark and Appalachian Mountains. It encompasses 12 states and all of them are home to fleas, ticks, and mosquitoes. These parasites can cause discomfort and pass on dangerous diseases to your pet.

Ultimately, the best way to protect your pet is by consistently administering parasite prevention year-round, regardless of your location or whether your pet ventures outdoors.

Use this regional Midwestern guide to understand the danger that mosquitoes, fleas, and ticks pose to your pet in the states of Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Montana, Nebraska, North Dakota, South Dakota, Ohio, and Wisconsin.

Heartworm Disease in the Midwest

Heartworm disease is a growing concern in the Midwest due to warming weather and the movement of animals across state lines.

Dogs and cats become infected if they are bitten by a mosquito carrying the Dirofilaria immitis parasite, known as heartworm. This parasitic worm multiplies in the pulmonary arteries (blood vessels that carry blood from the heart to the lungs) of pets and causes heartworm disease. While dogs are more likely to get heartworm than cats, felines are also susceptible to the disease.

Unfortunately, feline heartworm testing isn’t as effective as canine heartworm testing. This is because cats generally have low adult worm burdens. This means there may not be enough antigen produced by the heartworms to yield a positive test result. “So then our tests don’t show a positive result,” says Dr. Elizabeth Clyde, a small animal veterinarian in Illinois and a member of the board of directors for the American Heartworm Society (AHS). “But because our tests don’t work well in cats, people think, ‘Oh, cats can’t get heartworm,’ but they do.”

Increasing temperatures across the U.S. are contributing to more mosquito activity. According to Dr. Clyde, mosquitoes can start reproducing when temperatures hit 50 to 55 degrees Fahrenheit. Midwestern states have seen temperature increases between 1.5 – 3 degrees since the beginning of the 20th century [1]. This means that more days in the calendar year are hovering at or above temperatures where mosquitoes can reproduce. With larger mosquito populations, a pet’s risk of contracting heartworm disease increases.

Additionally, heartworm disease continues to spread in the Midwest due to the transport of shelter animals from other areas of the country according to Dr. Roberto Cortiñas, a veterinary parasitology professor at the University of Nebraska–Lincoln School of Veterinary Medicine and Biomedical Sciences. He notes that states tend to see an increase in shelter pets coming from the South during and after major weather events (like Hurricane Katrina), contributing to the rise of heartworm cases in the region.

Heartworm hotspots vary in every state, given the expansive size of many Midwestern states and the differences in landscapes within state borders. “Just because you’re in one part of the state, you can’t assume that what’s happening at the other side is the same,” says Dr. Cortiñas.

While many Midwestern states had historically lower incidences of heartworm-positive pets than other regions of the country, the numbers are changing, according to the most recent heartworm incidence map from the American Heartworm Society. In fact, states including Kansas and North Dakota saw the development of new heartworm hotspots and the urban areas of Boise and Bismark both saw significant heartworm increases.

The best defense against this dangerous disease is protecting your pet year-round with a veterinarian-prescribed heartworm preventative.

Fleas in the Midwest

Fleas can transmit diseases – like murine typhus and the plague – and serve as vectors for tapeworms in both dogs and cats. Plus, let’s not forget all of the itching and discomfort caused by flea allergy dermatitis.

Cat fleas are the most prevalent type of flea that bites dogs and cats across the Midwest.

Dr. Jo Myers, a practicing small animal veterinarian and graduate of Iowa State University College of Veterinary Medicine, predicts that Midwestern states will experience increased flea populations and activity as winters become shorter and warmer. When winters are mild, fleas may start emerging from outdoor areas as early as March [2].

Certain Midwestern states, like North Dakota, have a shorter flea season compared to other states in the region. However, once fleas make their way indoors, they can survive year-round, taking up residence in pet beds, mattresses, and carpets while feeding on you and your pet.

Dr. Myers also points out that as rural areas in the Midwest continue to develop, pets are more likely to come into contact with wildlife that carry fleas into residential areas.

Treating your pet year-round with flea medication is the best method of keeping your family safe.

Ticks in the Midwest

Out of focus Golden Retriever in background with tick on a human finger in the foreground

The Midwest has high populations of deer, which unfortunately also means a thriving community of ticks and tick-borne diseases. The management of deer populations, changes in habitat, and the effects of climate change are all contributing to the rise in these parasites across the Midwest.

The following ticks exist in Midwestern states and may transmit specific diseases to pets:

Lyme disease – deer tick/black-legged tick
Anaplasmosis – deer tick/black-legged tick, brown dog tick
Babesiosis – deer tick/black-legged tick, brown dog tick, Asian longhorned tick
Ehrlichiosis – lone star tick, brown dog tick
Rocky Mountain spotted fever – American dog tick, brown dog tick, Rocky Mountain wood tick
Tick paralysis – deer tick/black-legged tick, lone star tick, and American dog tick

Here’s a closer, state-by-state look at tick trends in the Midwestern United States.

Ticks in Illinois

Illinois has harsh, cold winters, partly due to its proximity to the Great Lakes. This is good news because it means the state doesn’t have quite as large or diverse tick populations as found in more southern states. Nonetheless, “the burden is still high enough that monthly prevention is absolutely necessary,” says Dr. Megan Cave, an emergency veterinarian at Veterinary Emergency Group located in Chicago, Illinois.

Types of Ticks in Illinois Dangerous for Pets

American dog tick
Lone star tick
Deer tick (black-legged tick)
Brown dog tick

Tick-Borne Diseases in Illinois

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Cytauxzoonosis
Babesiosis
Tularemia

Dr. Cave notes a growing trend among pet parents administering monthly parasite prevention, which has led to a decrease in the incidence of tick-borne diseases she sees in her practice.

Ticks in Indiana

Ticks in Indiana are gaining attention from residents and public health officials as their numbers (and the diseases they bring) continue to increase, according to the Indiana University Environmental Resilience Institute. The University points to three main factors in their prevalence across the state: Rising temps, habitat fragmentation, and increasing populations of deer and mice. For instance, deer ticks are typically inactive when temperatures dip below freezing but now pose a year-round risk with peak activity during the spring and summer months.

Types of Ticks in Indiana Dangerous for Pets

As of 2023, the list of ticks in Indiana has expanded with the addition of the Asian longhorned tick, a non-native species to the United States. Since the first sighting of the Asian longhorned tick in Dubois County, Indiana, in April 2023, the state has become the 19th in the U.S. to spot the species [3].

Lone star tick
Deer tick (black-legged tick)
American dog tick
Gulf Coast tick
Asian longhorned tick

Tick-Borne Diseases in Indiana

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Babesiosis
Anaplasmosis
Tularemia

Indiana University reports a significant increase in human Lyme disease cases from 2013 to 2017, more than doubling during this period. Cases of ehrlichiosis also rose to over five times compared to the previous five years and Rocky Mountain spotted fever cases surged to more than 13 times [4]. Although Lyme disease cases peaked in 2022 and decreased slightly in 2023, they remain higher than in previous years [5].

Ticks in Iowa

Generally, ticks are most active in Iowa from March through November [6]. While the Asian longhorned tick is not known to have made its way into Iowa to date, it’s been spotted as far north as Linn County, Missouri [7]. Deer ticks remain a concern as a vector for Lyme disease in Iowa, being especially abundant in the Northeastern and Eastern parts of the state. However, populations have been documented in almost every county. Experts warn to check yourself and your pets after enjoying outdoor activities.

Types of Ticks in Iowa Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American dog tick

As of 2019, American dog ticks made up the highest population of ticks in Iowa (68%), followed by deer ticks (25%), and lone star ticks (7%) [8].

Tick-Borne Diseases in Iowa

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Babesiosis
Anaplasmosis
Cytauxzoonosis
Tularemia

Tick-borne diseases are increasingly being detected in pets living in Iowa, says Dr. Myers. Lyme disease cases are on the rise, particularly in the Northeastern region of the state. However, Myers offers some reassurance, saying, “Iowa is not traditionally an area that sees a high number of anaplasmosis cases.”

Ticks in Kansas

In Kansas, ticks are most active from March through September, especially in grasslands and forested areas [9]. Deer ticks pose a significant concern as carriers of Lyme disease in Kansas, particularly in the eastern region where cases are increasing. American dog ticks are prevalent throughout the state, while lone star ticks have become common in the eastern half and have been found as far west as Mitchell County.

As the only species capable of living indoors year-round, the brown dog tick is found in kennels and homes across Kansas. These ticks often crawl into ceilings or seek out cracks and crevices along floors where they molt and lay their eggs.

Types of Ticks in Kansas Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American dog tick
Brown dog tick

Tick-Borne Diseases in Kansas

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Babesiosis
Anaplasmosis
Tularemia
Cytauxzoonosis (most common in Riley, Pottawatomie, and Geary counties) [1 0]

Ticks in Michigan

Deer ticks remain a growing concern in Michigan, particularly in the western and northern counties of the state. American dog ticks are widespread in Michigan’s forests and grassy areas from early May to November, while lone star ticks are occasionally found in wooded and grassy regions.

Types of Ticks in Michigan Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American dog tick
Brown dog tick

Tick-Borne Diseases in Michigan

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever (rare in Michigan)
Babesiosis
Anaplasmosis
Alpha-gal syndrome
Tularemia

Ticks in Minnesota

When it comes to ticks in Minnesota, deer ticks are the primary concern due to their spread of Lyme disease. They’re active basically any time snow isn’t on the ground or the temperature is above freezing. This is typically from March through October, with peak activity occurring in May [11].

Types of Ticks in Minnesota Dangerous for Pets

Lone star tick (rare in Minnesota)
Deer tick (black-legged tick)
American dog tick

Tick-Borne Diseases Found in Minnesota

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever (rare in Minnesota)
Babesiosis
Anaplasmosis
Tularemia

Ticks in Montana

The Rocky Mountain wood tick is the most abundant tick species in Montana, often found along stream corridors, grassy meadows, and south-facing sagebrush slopes. In eastern Montana, the American dog tick predominates, while the brown dog tick can make its way indoors across the state. To date, the deer tick has not been identified in Montana [12].

Types of Ticks in Montana Dangerous for Pets

Rocky Mountain wood tick
American dog tick
Brown dog tick

Tick-Borne Diseases Found in Montana

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Babesiosis
Anaplasmosis
Tularemia

Ticks in Nebraska

In the last 30 years, Nebraska has seen the arrival of new tick species, such as the lone star tick. It was first documented in Nebraska in 1990 and has progressively spread northward into areas where it was not previously found.

Types of Ticks in Nebraska Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American Dog Tick
Gulf Coast tick (rare in Nebraska)

Tick-Borne Diseases in Nebraska

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Cytauxzoonosis
Babesiosis
Tularemia

Ticks in North Dakota

The most common ticks in North Dakota are the American dog tick and the deer tick. The lone star tick is limited to isolated sightings, mostly in wooded areas with thick undergrowth and around animal resting areas. The Rocky Mountain wood tick is mostly found in the western edge of the state [13].

Types of Ticks in North Dakota Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American dog tick
Rocky Mountain wood tick

Tick-Borne Diseases in North Dakota

Lyme disease
Ehrlichiosis
Rocky Mountain spotted fever
Colorado tick fever
Babesiosis
Tularemia

Ticks in South Dakota

In South Dakota, ticks are active when temperatures are above freezing. Fortunately, Lyme-carrying deer ticks are not found throughout the state but rather isolated to the eastern third. American dog ticks have peak activity during the spring and summer months, spanning May to August, and are found across the entire state. The lone star tick is limited to isolated sightings in the southeast corner from April to late August. Meanwhile, the Rocky Mountain wood tick is prevalent in the western edge and is most active from late spring to early summer [1 4].

Types of Ticks in South Dakota Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
Rocky Mountain wood tick
American dog tick

Tick-Borne Diseases in South Dakota

Lyme Disease
Ehrlichiosis
Rocky Mountain spotted fever
Babesiosis
Anaplasmosis
Tularemia

Ticks in Ohio

Since 2010, Ohio has experienced an upswing in deer ticks statewide. Adult ticks are active during spring, fall, and winter, while nymph deer ticks are most active in spring and summer. Both can transmit Lyme disease to humans and pets. American dog ticks are active from mid-April to mid-July [15].

Where might you and your pets run into ticks in Ohio? Lone star ticks are mainly found in southern Ohio, but because they’re carried and dispersed by migratory birds, they’re found throughout the state [16]. Deer ticks are usually found in wooded areas and the American dog tick in grassy areas and road edges.

Types of Ticks in Ohio Dangerous for Pets

American dog tick
Brown dog tick
Lone star tick
Deer tick (black-legged tick)
Asian longhorned tick (identified in July 2023 [3])

Tick-Borne Diseases in Ohio

Rocky Mountain spotted fever
Tularemia
Lyme disease
Babesiosis
Tularemia
Ehrlichiosis

Ticks in Wisconsin

Like other states in the Midwest, Wisconsin, is seeing a rise in winter temperatures. As a result, tick populations have expanded across the state with feeding and breeding seasons beginning earlier and lasting longer than in past years [1 7].

Types of Ticks in Wisconsin Dangerous for Pets

Lone star tick
Deer tick (black-legged tick)
American dog tick

Tick-Borne Diseases in Wisconsin

Lyme disease
Babesiosis
Ehrlichiosis
Tularemia
Anaplasmosis

The most common tick-borne illness in Wisconsin is Lyme disease, with most cases occurring in the late spring, summer, or early fall when ticks are most active and people and their pets are enjoying the outdoors [1 7].

Living in the Midwest: Protecting Your Pet From Parasites

Woman bending down on trail to take tick off of dog

Those living in the Midwest have seen big shifts in the weather over the past decade. These shifts in climate, combined with changes in landscapes and the movement of pets and humans, heighten the risk of pets encountering parasites throughout the year.

Dr. Cortiñas warns that the typical parasites in the Midwest may not be the only concern for long. New parasites are already emerging in areas they don’t typically live—such as the Asian longhorned tick. With new parasites come new diseases. Purchasing the most up-to-date preventatives for your pet can protect them against parasites and diseases.

Dr. Cortiñas provides these tips for administering parasite preventatives:

Never use expired medicine.
Always give the dose as directed. Splitting doses will not effectively protect your pet.
Give the medicine according to the proper schedule.
Follow application directions closely, including applying topical medications directly to the skin rather than on top of the fur.
If you’re unsure how to properly administer your pet’s medication or would like verification that you’re doing it correctly, ask your veterinarian for a demonstration.

Preventatives protect your pet from many parasites, including heartworms. However, Dr. Clyde suggests that if you’re venturing out with your pup when mosquitoes are abundant, you can consider using dog-safe bug repellent for extra protection.

And don’t underestimate the importance of routine check-ups. Even if your pet seems healthy, preventive care is your best chance of catching issues early.

Keep in mind, the parasites lurking outside shouldn’t keep you and your pet from enjoying the state you live in. With proper precautions, your cat or dog can remain safe and harm-free.

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