Mosquitoes and ticks are more than a nuisance. Dogs can contract heartworms from a mosquito bite, and ticks that attach to a dog can transmit the organisms that cause Lyme disease, ehrlichiosis, and anaplasmosis. Dogs are often screened for these disease agents using a small blood sample obtained at their wellness exam, because knowing whether they have been exposed to vector-borne diseases is important—these four diseases can be life-long and life-threatening for dogs. 

Heartworm disease in dogs

Mosquitoes are the vector for heartworms, which can cause serious heart and lung damage in dogs.

  • Infection route When a mosquito bites, they can transmit the heartworm in microscopic form to your dog. Mosquitoes in every state carry heartworms.
  • Disease course The worms migrate through the dog’s blood stream to live in the heart and pulmonary arteries, where they cause inflammation and block blood flow. Coughing is the initial sign, followed by fatigue, weight loss, and heart failure.
  • Treatment options Heartworm treatment, which lasts several months, is tailored to each dog’s situation and includes antibiotics to weaken the worms, medication to kill the microscopic, immature worms, and injections to kill the adult worms in the heart. Your dog will require hospitalization and close monitoring, and must be restricted from exercise for an extended period.
  • Recovery prognosis If diagnosed early, heartworm disease has a good prognosis for full recovery, although treatment is long and difficult, and not without risk. Severely affected dogs cannot survive treatment, and ultimately succumb to heart failure.
  • Prevention methods — Mosquito repellent and environmental control, as well as a regular heartworm medication protocol, are important steps in heartworm disease prevention. 

Lyme disease in dogs

Ticks transmit the organism that causes Lyme disease in dogs. People also suffer with Lyme disease.

  • Infection route Lyme disease is caused by a spirochete called Borrelia burgdorferi. The deer tick, Ixodes scapularis, transmits Lyme disease after being attached to your dog for approximately 48 hours. 
  • Disease course Lyme disease in dogs has a different course than in people. Ninety percent of dogs who contract Borrelia do not develop Lyme disease, despite exposure, testing positive, and harboring the organism. The other 10% of dogs can develop a fever and arthritis weeks to months after the tick bite, and a few develop chronic kidney problems.
  • Treatment options Dogs with Lyme disease signs typically respond in a few days to a course of antibiotics, although infected dogs are never entirely cleared of the organism.
  • Recovery prognosis — Except for the few who develop kidney complications, dogs remain symptom-free following treatment.
  • Prevention methods Our veterinarians can prescribe a tick preventive that will kill ticks before the 48-hour window, so disease may not be transmitted to your dog. 

Ehrlichiosis in dogs

Ticks also transmit the bacterial organisms that cause ehrlichiosis in dogs.

  • Infection route The bacteria Ehrlichia canis and Ehrlichia ewingii, which are transmitted by the brown dog and lone star tick, respectively, are the main cause of ehrlichiosis in dogs. 
  • Disease course Ehrlichia canis can cause dogs to feel sick and have low blood platelets, and can be acute, subclinical, or chronic. Acute disease occurs one to three weeks after the tick bite, and chronic symptoms can arise months to years later. 
  • Treatment options Dogs can be treated with antibiotics.
  • Recovery prognosis — The prognosis is good for dogs who are treated at an early infection stage. Chronically infected dogs may have decreased white blood cells, kidney disease, and neurologic disease, and their prognosis is poor. 
  • Prevention methods — To help prevent ehrlichiosis in dogs, environmental control (e.g., not walking your dog in grassy areas where ticks abound), nightly tick checks to remove ticks, and tick preventives are crucial. Screening tests that can detect infection in the early stages and allow prompt treatment can help prevent chronic disease.

Anaplasmosis in dogs

Ticks are also the culprit for anaplasmosis in dogs by transmitting the rickettsial agents that cause the disease.

  • Infection routeAnaplasma phagocytophilum and Anaplasma platys are rickettsia bacteria that are transmitted to dogs via tick bites. Different ticks, such as the deer and the Western black-legged ticks, carry the disease in different parts of the U.S.
  • Disease course — Anaplasmosis signs, including arthritis, lethargy, fever, and bruising, occur in dogs one to two weeks following the tick bite.
  • Treatment options — Antibiotics are prescribed to treat anaplasmosis in dogs, along with anti-inflammatory and pain medications.
  • Recovery prognosis  The recovery prognosis in dogs is generally good. Screening for several tick-borne diseases is important, since dogs who contract one tick-borne disease often contract another.
  • Prevention methods — Clear tall brush around the home and mow grass frequently to discourage ticks. Your veterinarian can prescribe effective tick control products for your dog.

As the Bay area’s only 24-hour urgent care facility, Animal Internal Medicine and Specialty Services is available to answer any questions and address any problems with mosquito and tick-borne diseases in your dog any time, any day. We do not want your dog to ever experience these serious problems, so do not hesitate to call our caring specialists.