Diseases from Ticks - Lyme Disease, Rocky Mountain Spotted Fever, & More

Close up of a tick on a dog which can carry diseases from ticks
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Although ticks may be more active during the warmer months, they are year-round threats to dogs and cats. Tick season is usually from April to September — but these insects can also become active during the fall. As further explained by Sploot’s veterinarian, Dr. Allison Kihn, “Ticks become active at 40°F, which is much cooler than many pet parents might expect.” 

So apart from the itchiness that ticks cause and their activity during many seasons of the year, are there other reasons to be ‘ticked off’ by these skin parasites? Well, yes! 

Ticks are ‘vectors’ (carriers) of various diseases that can affect dogs, cats, and humans. These insects transmit harmful pathogens (i.e. bacteria, protozoa) through their bite or through accidental ingestion of the infected tick. 

Awareness about diseases from ticks is a vital defense for pet parents and their fur babies. Read on to learn about some of the common diseases from ticks that pets AND pet parents can contract — and how to recognize them.

1. Lyme Disease

  • Commonly carriers: black-legged tick (deer tick), western black-legged tick
  • Affects: dogs, cats, & humans

Cause & Prevalence

First on our list of diseases from ticks is one of the most widely known ones: Lyme disease. This tick-borne disease is caused by the bacterium ‘Borrelia burgdorferi’ and transmitted through the bite of infected ticks. Lyme disease can target various systems of the body, including the joints, nervous system, heart, kidneys, and skin

Lyme disease is relatively more common in dogs than in cats. As for humans, Lyme disease is one of the most common diseases that are carried by a vector insect; in the United States alone, around 20,000 to 30,000 cases of Lyme disease in humans are reported each year.  

Symptoms in Pets

Symptoms of Lyme disease in dogs and cats may include:

  • Fever
  • Loss of appetite
  • Fatigue
  • Lameness
  • Joint pain & swelling

If left untreated, Lyme disease in dogs and cats can lead to complications affecting vital organs and systems such as the nervous system, heart, and kidneys. Lyme disease in dogs can be fatal; and although very rare, Lyme disease can also be fatal for cats. Therefore, if you observe the above symptoms in your pet, schedule a sick visit with your veterinarian. 

Note: As mentioned above, Lyme disease can affect humans. This disease needs prompt treatment to prevent complications. To learn about the symptoms of Lyme disease in humans, here is a resource you can check out: Lyme Disease | CDC

A photo to represent a dog with fatique, a symptom of Lyme disease in dogs, one of the diseases from ticks

2. Rocky Mountain Spotted Fever (RMSF)

  • Common carriers: American dog tick, Rocky Mountain wood tick, brown dog tick 
  • Affects: dogs, cats, & humans

Cause & Prevalence

Next on our list of diseases from ticks is another commonly known one: Rocky Mountain Spotted Fever (RMSF). This disease is caused by the bacterium ‘Rickettsia rickettsii’ and is transmitted through the bite of infected ticks. Primarily, RMSF targets the cellular lining of blood vessels.

Rocky Mountain Spotted Fever is more common in dogs than in cats. Humans can also get RMSF from infected ticks; in fact, around 250 to 1200 human RMSF infections are reported each year in the United States. 

Symptoms in Pets

Symptoms of Rocky Mountain Spotted Fever in dogs and cats include:

RMSF can lead to complications involving the blood vessels and other organs — a common outcome without treatment. In some cases, untreated Rocky Mountain Spotted Fever can be fatal for dogs and cats. We encourage pet parents to contact a veterinarian upon observing any of the above symptoms in their pets.  

Note: Rocky Mountain Spotted Fever can be fatal for humans too. To learn about the symptoms of Rocky Mountain Spotted Fever in humans, here is a resource you can check out: Rocky Mountain Spotted Fever (RMSF) | CDC

3. Ehrlichiosis

  • Common carriers: lone star tick, black-legged tick (deer tick)
  • Affects: dogs, cats, & humans

Cause & Prevalence

Ehrlichiosis can be caused by different species of ‘Ehrlichia bacteria,’ including Ehrlichia canis, Ehrlichia ewingii, and Ehrlichia chaffeensis. These bacteria are transmitted through the bite of an infected tick. In dogs, cats, and people, Ehrlichia bacteria primarily infect the white blood cells

Though Ehrlichiosis does not have the same prevalence as other diseases from ticks that are featured on this list, it is recommended that pet parents be aware of its symptoms because untreated Ehrlichiosis poses serious health risks.

Symptoms in Pets

Symptoms of ehrlichiosis in dogs and cats include: 

  • Fever
  • Lethargy
  • Loss of appetite
  • Swelling in the lymph nodes
  • Unexplained bruising and bleeding

Left untreated, ehrlichiosis in pets can cause serious illness and may lead to complications such as low blood cell counts, kidney disease, and bleeding from the nose. The bacteria may also spread to vital organs like the eyes (causing bleeding and blindness), liver, spleen, lungs, etc. Chronic ehrlichiosis can be fatal to pets. We encourage pet parents to seek veterinary attention if they observe any of the above symptoms in their pets. 

Note: Untreated ehrlichiosis in humans can also be life-threatening. To learn more about the symptoms of ehrlichiosis in humans, here is a resource you can check out: Ehrlichiosis | CDC

: A photo symbolizing a cat with a fever, one of the symptoms of ehrlichiosis, one of the diseases from ticks

4. Anaplasmosis

  • Common carriers: black-legged tick, western black-legged tick
  • Affects: dogs - as well as humans & cats (depending on the bacterial species)

Cause & Prevalence

Next on our list of diseases from ticks is anaplasmosis. This disease is commonly spread by ticks that carry the causal pathogens: ‘Anaplasma phagocytophilum’ and ‘Anaplasma platys’. Anaplasmosis is spread through the bite of these infected ticks.

A. phagocytophilium, which primarily affects white blood cells, can infect humans and dogs — in rare cases, cats as well. 

Meanwhile, A. platys, which targets the blood’s platelets, primarily affects dogs. Of the two bacterial species, A. phagocytophilium is more commonly observed, even among dogs. 

Symptoms in Pets

Symptoms of anaplasmosis in pets (caused by A. phagocytophilium) include:

  • Fever
  • Lethargy
  • Joint pain
  • Loss of appetite
  • Vomiting or diarrhea (in some cases)

Symptoms of the less common anaplasmosis in dogs (caused by A. platys) include: 

  • Fever
  • Lethargy
  • Pale gums
  • Red splotches
  • Bruising
  • Nosebleeds

Severe cases of untreated anaplasmosis in pets can result in low counts of white blood cells (critical cells for immune system function) or low counts of platelets (critical cells for effective blood clotting). The affected cells would depend on whether ‘A. phagocytophilium’ or ‘A. platys’ caused the infection.

In severe cases, organ failure and death can occur.  Therefore, we recommend that pet parents reach out to a veterinarian if they observe any of the above listed symptoms. 

Note: One of the bacterial species mentioned above, A. phagocytiphilium, can infect humans — and some cases are life-threatening. To learn about the symptoms of anaplasmosis in humans, here is a resource you can refer to: Anaplasmosis | CDC

5. Babesiosis

  • Common carrier: black-legged tick (deer tick) 
  • Affects: humans, dogs, & cats 

Cause & Prevalence

Babesiosis is a disease caused by protozoan parasites coming from the ‘Babesia’ genus and transmitted through the bite of an infected tick. The microscopic protozoa that cause Babesiosis infect the red blood cells of the body. 

Though rarely observed in cats, babesiosis is considered an emerging infection in dogs and humans, meaning that the number of cases has increased in recent times.

Symptoms in Pets

Some infected pets may be ‘asymptomatic’ (having no symptoms). Meanwhile, some infected pets will show symptoms of acute babesiosis, such as the following:

  • Fever
  • Weight loss
  • Weakness
  • Pale gums
  • Dark urine 

Left untreated, severe cases of babesiosis in pets can cause progressive anemia, organ failure, and systemic shock. Some cases of babesiosis in pets can lead to death. Upon seeing any of the above symptoms, it is recommended that pet parents schedule a veterinary consultation.

Note: Babesiosis in humans can be life-threatening when left untreated. To learn more about the symptoms of babesiosis in humans, here is a resource you can refer to: CDC - Babesiosis

A dog on a weighing scale to symbolize weight loss in dogs, one of the symptoms of babesiosis in dogs, one of the diseases from ticks

April to September

6. Hepatozoonosis

  • Common carrier: brown dog tick
  • Affects: dogs & cats

Cause & Prevalence

Hepatozoonosis is caused by parasitic protozoa coming from the Hepatozoon genus, transmitted via the ingestion of an infected tick. Dogs and cats have specific Hepatozoon species that can infect them.  For dogs, the causal pathogen is either ‘Hepatozoon canis’ or ‘Hepatozoon americanum’. Meanwhile, in cats, the causal pathogen is primarily ‘Hepatozoon felis’. Hepatozoa primarily affect red blood cells.

Hepatozoonosis is considered rare in cats. However, it is common for cats to be more prone to this disease if they are already immunocompromised due to FeLV (a life-long viral infection that can be prevented with feline vaccines). Meanwhile, hepatozoonosis in dogs is an emerging disease. 

Unlike some of the other diseases from ticks on this list, hepatozoonosis does NOT affect humans.

Symptoms in Pets

In cats, hepatozoonosis is not just rare, it is also often subclinical, meaning the disease is typically not severe enough to show symptoms. 

But in cases wherein pets are symptomatic, these are the symptoms of hepatozoonosis to watch out for:

  • Fever
  • Lethargy
  • Loss of appetite
  • Discharge from eyes and nose
  • Enlarged lymph nodes
  • Muscle loss or wasting
  • Pale gums

Left untreated, hepatozoonosis in dogs or cats can be debilitating, causing damage to the kidneys and blood vessels. This is why we encourage pet parents to reach out to a veterinarian upon seeing the above symptoms of hepatozoonosis. 

Final Thoughts About Preventing Diseases From Ticks

Promptly removing ticks from your dog or cat is crucial in reducing the risk of all of the above diseases from ticks. To get the best tick preventives and tick control strategies, consult your veterinarian. This is especially important during tick season, which happens during warmer months.

For pet parents in Denver, Sploot Veterinary Care is here to help you prevent or treat ticks in pets! Our experienced veterinarians provide guidance on all aspects of your fur baby’s health. Schedule a visit today or come on in for a same-day appointment in any of our convenient locations. Our clinic doors are open daily, for extended hours

Till next time, we’re with you every pounce of the way.