Spring has sprung in Central Ohio, which means long walks in the park, hikes through the woods, and picnics in the grass with your dog. Unfortunately, spring also brings ravenous pests, such as mosquitoes and ticks, who emerge from their winter hiding places, ready to feed on your pet. A mosquito or tick can do more than cause your pet an itchy bite—they can transmit a number of dangerous diseases, including heartworm, ehrlichiosis, anaplasmosis, and Lyme disease.  

Heartworm disease

Heartworm disease is caused by a parasitic worm, Dirofilaria immitis, that is transmitted when a mosquito bites an infected dog, wolf, coyote, or fox, and picks up microscopic larval worms with its blood meal that can be passed on to other dogs it bites. Larval worms deposited in your pet’s body mature over several months, and migrate to large lung vessels and the heart. Once the worms are fully mature, which takes approximately six months, they multiply to produce many more worms, and the parasites exponentially increase in your pet’s body.

Heartworms cause severe lung damage, heart disease, and damage to other body organs, and are fatal if not treated. Treatment kills adult worms, as well as circulating larval worms (i.e., microfilariae), but is hard on pets, as dead worms can become lodged in lung vessels, to cause a deadly pulmonary embolism. Fortunately, heartworm disease is easy to prevent by regular administration of a preventive medication. Many options are available—speak with a Westerville Veterinary Clinic team member about the best preventive for your pet. 


Canine ehrlichiosis is caused by a bacteria, Ehrlichia canis, that is transmitted by several tick species. Once inside your dog’s body, the bacteria attacks the white blood cells, and may cause short-term signs that may include:

  • Fever
  • Lethargy
  • Decreased appetite
  • Lymph node swelling
  • Limb swelling
  • Coughing
  • Difficulty breathing
  • Splenic enlargement
  • Decreased platelet numbers

Dogs often spontaneously recover from the initial phase, and may become infection-free, or may develop long-term disease. Chronic Ehrlichia infection can affect almost any body system, and can cause dangerous complications, including:

  • Severe weight loss
  • Kidney failure
  • Splenic enlargement
  • Lung inflammation
  • Ocular inflammation
  • Neurologic problems
  • Decreased platelet numbers
  • Other blood cell deficiencies

Unfortunately, many of these complications can lead to significant organ damage, and death, if ehrlichiosis is not treated promptly. Routine testing is critical to detect infection in its early stages, so appropriate antibiotics can be administered, to prevent life-threatening effects. 


Anaplasmosis is caused by bacteria of the species Anaplasma phagocytophilum and Anaplasma platys, which are transmitted through a tick bite. Anaplasma phagocytophilum infection most commonly causes arthritis that affects multiple joints, and affected dogs experience joint pain and lameness. Less common disease manifestations include:

  • Vomiting
  • Diarrhea
  • Coughing
  • Breathing difficulties
  • Meningitis
  • Neurologic problems

Anaplasma platys infection causes infectious cyclic thrombocytopenia, or periodic platelet deficiencies, that can lead to blood clotting problems. Affected dogs may develop bruising or petechiae (i.e., multiple, pin-point bruises) on the skin, lose blood in the feces or urine, or have nose bleeds. Anaplasma infections can also be treated with antibiotics, but early detection is important, to prevent long-term joint or organ damage. 

Lyme disease

Lyme disease is caused by an infection with the bacteria Borrelia burgdorferi. Several tick species can transmit the bacteria, but the deer tick, or black-legged tick, is the most common culprit. Lyme disease can cause vague, generalized illness signs, such as:

  • Fever
  • Lethargy
  • Decreased appetite
  • Painful joints
  • Lameness
  • Swollen lymph nodes

Without treatment, Lyme disease can damage the heart, nervous system, or kidneys, and kidney failure that may result is typically fatal. With prompt diagnosis, antibiotics can be prescribed to kill the bacteria, and prevent organ damage. 

Preventing heartworm, ehrlichiosis, anaplasmosis, and Lyme disease

Although these diseases can cause significant illness or death in your pet, you can take action for prevention or early detection, when treatment can prevent long-term damage. Include these practices to keep your dog healthy:

  • Use year-round heartworm prevention — In central Ohio, where the weather is notoriously unpredictable, mosquitoes can become active any month of the year. Year-round heartworm prevention is critical, to prevent deadly heartworm disease.
  • Use year-round tick prevention — Ticks typically only transmit diseases after being attached for several hours, so use a product that quickly kills ticks that wander onto your dog during walks or hikes. One of our team members can help you choose a product that best fits your dog’s needs.
  • Check your pet for ticks — After a foray into the woods or high grass, check your dog carefully for any hitch-hiking pests. Pay particular attention to her head, ears, armpits, and groin area. If you find a tick, remove it carefully using tweezers—never heat or alcohol, as unpleasant stimuli can cause the tick to suddenly release its stomach contents, including disease-causing organisms, into your pet.
  • Test for disease annually — We recommend annual testing for these common diseases. One simple blood test can tell us if your pet has heartworm disease, or has been exposed to Ehrlichia, Anaplasma, or Lyme disease. If disease is detected early, important treatment can be administered before long-term damage is done. If you find a tick on your pet, call us for advice, as we may recommend more frequent testing, to determine whether your dog was exposed to disease-causing bacteria.

Is your dog due for her heartworm or tick preventive refill, or annual disease testing? Call us to schedule this important appointment.