Photo by Ame Vanorio

Climate Change And Top 6 Parasites

Warmer winters are contributing to an increase in parasite populations. Parasites are having a greater number of life cycles in addition to spreading to new locations. This is affecting the health of our pets and livestock. 

Climate change is in the news and for good reason. Weather patterns are changing with many areas experiencing warmer wetter weather or increased dryness and droughts. Climate change means that weather patterns are significantly changing.

 Part of climate change is global warming. According to the U.S. National Oceanic and Atmospheric Administration (NOAA), the temperatures in the United States are on average 1.5 degrees warmer than they were one hundred years ago. 

That might not sound like a lot but there is just one degree between rain and snow. It also increases the melting of ice in polar regions. These changing weather patterns are affecting populations of animals and plants. 

By Heather Moreton from Louisville, KY, USA - Belgian Horse at the Kentucky Horse ParkUploaded by Princess Mérida, CC BY 2.0,
Photo by Heather Moreton

How Does This Affect Us In Kentucky? 

Disease-carrying parasites are increasing due to warmer weather. Warmer temperatures give the parasites greater opportunity to complete their life cycles. Sometimes having multiple cycles per season.

Many of them overwinter in the soil. The risk of one of your animals having parasites increases when the environment is suitable for the parasite or their host. 

To put that in simpler terms. Many of us have been to Florida. Florida summers are hot and humid and the winters are also warm. They have mosquitoes year-round and the state of Florida continually battles them.

Florida’s government sprays insecticides to try to control the mosquito population. They do this because mosquitoes are a vector for many diseases.  Our weather in Kentucky is becoming warmer, like Florida, and we are seeing more parasites.

Isn’t Winter Parasite Free? 

Like me, you may be someone who once considered winter to be a parasite-free zone. The ground froze for long periods of time and many pest insects, parasites, and microbes would die off. In the past, I would worm my animals in November and not worry about it again till March.

Those days are gone. Just yesterday I was looking at my horse and thinking he had lost a few pounds. Then I realized with the recent warm weather I should probably do a fecal and check for worms.

Yup. He needs to be wormed. Winter is not the time to slack on parasite prevention. 

When we have warmer weather the parasites survive longer in the soil. So this year we are having a warm wet winter. Problems such as Coccidia, Heartworm, Hookworms, Lyme disease, Anaplasma, and Rocky Mountain Spotted Fever are more common in warmer winters. 

Parasites That Live In Warmer Temperatures


Coccidia is a single-celled animal that lives in the soil. Coccidiosis is widespread and affects livestock and pets. They are spread through fecal matter and very contagious. Coccidia is host-specific so one strain can not be transmitted between species.

Coccidia causes diarrhea and vomiting and can lead to severe dehydration and even death. Young animals are susceptible. This can especially affect calves, goat kids, and lambs who may be born out in the field. 

Coccidia is hard to kill and can overwinter in soils. Good prevention is important. Don’t feed your animals on the ground and keep feed and water buckets clean. Clean stalls or enclosures on a regular basis as the eggs are transmitted in fecal matter. 

By Uberprutser - Own work, CC BY-SA 3.0,
Livestock born in the field are susceptible to coccidia

Dirofilaria immitis (heartworm)

Heartworms are a growing concern. As the climate warms the mosquito population expands. Heartworms are now in all fifty states including Alaska and have increased in Kentucky.

Heartworm prevention is not something you can start and then stop. Your dog will need lifetime protection. You can read more about heartworms and prevention on our blog. 


Ancylostoma species (hookworms)

Hookworms are a serious parasite that lives in your pet’s digestive system. Dogs and cats get hookworms as well as cattle. In addition, people can contract hookworms from infected soil or animal feces. 

 Hookworm eggs are expelled in the feces of animals that are infected.  They then hatch into larvae and live in the soil. Animals may ingest the worms from the soil by eating feces. 

They can also get eggs on their bodies while being outside and ingest them while grooming. This commonly happens with dogs and cats. 

Hookworms like warm moist conditions. Eggs will begin to die when temperatures fall below 45 degrees Fahrenheit. However, larvae can withstand freezing temperatures for up to six days. Prolonged dry soil will cause them to die. 

One type of hookworm, Ancylostoma duodenale, was felt to be adapting to climate changes by undergoing developmental arrest in its larval forms in human tissues.  

Borrelia burgdorferi Lyme Disease

Lyme disease is a bacterial disease that is spread by the tick. It affects dogs, horses, and cattle as well as deer, squirrels, and raccoons. It has occurred in all states but is most prevalent in the upper mid-west and northeast.

Lyme disease is zoonotic which means humans can also get infected. The same tick that bites your dog may bite you as well. Lyme disease in humans can be quite serious.

The bacteria lives and is carried within the body of the tick. The ticks can live in a variety of eco-systems but prefer tall grasses, thick brush, and woods. Livestock Guardian Dogs and hunting dogs are at the highest risk. However, just letting your dog out in the backyard without protection is a risk.

By Alan R Walker - Own work, CC BY-SA 3.0,
Tick Ixodes ricinus, or deer tick, developmental stages. As you can see the nymphs are quite small.

In some ways, Lyme disease is a ghost illness. Wild animals who may be carriers often show no signs of illness. In addition, most cases of Lyme disease are spread by the nymphs or baby ticks which can be very hard to see and remove. A blood test is used to identify if the bacteria is in the body.

Symptoms in dogs may not appear until two to five months after they are bitten. Dogs and horses may appear lame, lethargic, or experience a decrease in appetite. Occasionally they have a fever. In more severe cases the bacterial infection can spread to the kidneys or heart and cause death. A thirty-day dose of antibiotics is typically prescribed to get rid of the bacteria.

Prevention is the answer! Dr. Glaza recommends NexGard for his dog patients to prevent flea and tick infestations. NexGard is approved by the FDA to “prevent the infection of Lyme disease”. We carry NexGard for dogs and Frontline for cats at the clinic to make it easy for you to come in and pick up a dose.

NexGard is available at the clinic

Anaplasma marginale Anaplasma in cattle

Anaplasma is a dangerous disease that affects cattle. It is spread primarily by ticks but also mosquitos and horse flies can be vectors. Farmers can also spread the disease by using unclean equipment while dehorning or castrating.

The disease invades the red blood cells causing high temperature, severe anemia, and rapid weight loss. It can cause cows to abort and bulls to become sterile. Severe cases can lead to death.

Cattle that survive can be a carrier for the disease. That means that the disease can continue to be spread among your herd.

Anaplasma is widespread in states such as Texas and Arkansaw. However, in the past several years Kentucky has seen an increased number of cases. With warmer weather, we are seeing an increase in vector parasites such as ticks and mosquitoes which spread the disease.

In Kentucky, we see most cases in the fall of the year. The University of Kentucky reports that most cases occur from mid-September through mid-November.

Some veterinarians recommend feeding VFDs (Veterinary Feed Directives) grain with added antibiotics. Dr. Glaza does not recommend this method. First off these prescription feeds may only be given to cattle that have been diagnosed with the Anaplasma. Secondly, they are expensive and may not prevent or treat the disease.

Prevention is the best policy. Anaplasma can be prevented by vaccination. You may purchase the vaccination from us at Licking Valley Veterinary Service. The recommended dose is two-injections given four weeks apart. This is an annual vaccine.

Rickettsia rickettsii (Rocky Mountain Spotted Fever)

This is the bacteria that causes Rocky Mountain Spotted Fever which affects both humans and other mammals. Primarily it affects dogs. 

Contrary to its name Rocky Mountain Spotted Fever (RMSF) is found throughout the USA.  

This bacterial disease causes fever, joint pain, and vomiting. It is transmitted by a bite from its carrier,  the brown dog tick or the wood tick out west. 

Ticks can carry several diseases and may be active year-round. Many tick species experience diapause which is a form of “rest” in colder weather. However, ticks such as the dog tick frequently wake up and move around when the temperature is over 35 degrees Fahrenheit.
Life cycle of a dog tick

Prevention is needed to prevent your pet from getting bitten by a tick. Using a topical flea and tick prevention is important. Keep areas where pets play mowed to reduce infestations.

If you have space you can also employ your poultry to eat the ticks. Guineas are active hunters of ticks. Wildlife can also be helpful. Opossums can eat 4000 ticks a month!
It is important to check your dog for ticks.

Talk To Your Veterinarian

Your veterinarian is familiar with what parasites are a problem in your area and what time of year is the greatest risk. With your vet work out a program so that your pets and livestock are getting regular treatments to prevent parasite infestations and diseases. 

At Licking Valley Vet we are happy to perform a fecal test to confirm any internal pests or microorganisms that may be affecting your animal’s health. 

Our pharmacy gives you the opportunity to conveniently order online and have it shipped to your home. Revolution, Bravecto, and Strongid are available online with a prescription from Dr. Glaza. We also carry some select medications in-house that you can pick up.

Author, Ame Vanorio, is the director of Fox Run Environmental Education Center and a licensed wildlife rehabilitator. She teaches onsite and online classes in organic gardening, solar power, and wildlife rehabilitation. She lives on her farm in Falmouth, Kentucky with too many animals to count! 

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