Ticks and Lyme disease

AVIS À NOS LECTEURS: tel qu’exigé par l’Ordre des médecins vétérinaires du Québec, pour se conformer aux codes de déontologie relatifs à la publicité, les chroniques informatives suivantes qui comportent le logo de notre entreprise, doivent être interprétées comme des publicités. (L’ajout du terme « publicité » sera ajouté progressivement sur chaque chronique au cours de l’année 2016).

What is Lyme disease?

Lyme disease or Borreliose is a bacteria (Borrelia burgdorferi) that causes an inflammatory disease in dogs and humans. Polyarthritis is the most frequent symptom observed in dogs with the disease.  In dogs, this disease manifests itself with fever, lethargy, swollen lymph nodes and limping.  Kidney inflammation (nephritis) is a more serious repercussion of Lyme disease.  Labradors, Golden Retrievers and Shetland Sheepdogs are the most susceptible breeds affected by Lyme nephritis.

Transmitting the bacteria

  • The bacteria that can cause Lyme disease in our region is transmitted by the deer tick (Ixodes scapularis).
  • The tick transmits the bacteria by a bite on the skin.  The tick`s adhesion on its host requires 48 hours before the bacteria can be transmitted.
  • The species primarily affected is the dog.  Dogs get the infection from adult ticks, contrary to humans that are most infected by the nymphs.
  • Adult ticks are most active in the spring and fall, as the larva and nymphs are most active during the summer months.

What is the situation in Quebec?

In the last 20 years in the United States and Europe the disease has been present in humans and dogs.  In Quebec, more positive tests are detected every year by blood test, as well as more cases are diagnosed with the disease itself.

How to diagnose Lyme disease?

  • Lyme disease is difficult to diagnose for many reasons.  The symptoms can resemble other diseases, as well as laboratory test such as urinalysis and blood test can be inconclusive.
  • The veterinarian must consider numerous factors before diagnosing that the dog has the disease such as the possibility that the dog could have been bitten by a tick 2 to 5 months prior, the presence of symptoms, the results of blood tests, the elimination of possible other causes, and depending on the case the response to treatment.

Initial test:

  • The SNAP 4DX test is used first.  This test is frequently used by veterinarians as it permits to detect the presence of heartworm in the dog.  A simple blood test is needed.
  • A dog that has been bitten by a deer tick transmitting the bacteria will produce antibodies.  For the Lyme test, the SNAP 4DX test will detect the presence of antibodies.
  • However, a positive test in a dog that has symptoms does not mean that it is caused by the bacteria in question.  In fact 70-90% of the dogs in the region could test positive for the bacteria.  A positive test simply means that the dog has been in contact with the bacteria that could cause Lyme disease.

Additional tests:

  • Following a positive SNAP 4DX test on a dog with or without symptoms, a second test is done the QC6 (quantitative test) and sent to the laboratory.  This test verifies the levels of the immune response.  If the values are high the more likely the infection.
  • A special urine test is also done in the dogs that have an elevated QC6 test.

The veterinarian must decide with all the information that was gathered if a treatment is necessary to treat the bacteria that could cause the Lyme disease.

What is the treatment?

The treatment consists of administering an antibiotic once daily for 4 weeks (6 weeks in the case of nephritis).  The clinical signs other than nephritis are usually reduced in less than 3 days; however relapses can occur because there is no efficient treatment to date to eliminate the bacteria completely from the body.  A QC6 test will reevaluate the levels 6 months after the diagnosis that is 5 months after the treatment.

How to prevent this disease?

A multimodal approach is recommended to prevent Lyme disease in dogs in this includes vaccination, the administration of a tick control medication (by the mouth or applied on the skin) that kills the tick at a variable time while feeding on the pet, and check your pet’s fur regularly.

  • A Lyme vaccine is recommended for the dogs that are at risk of getting bitten by a tick, living in or visiting high risk areas.
  • Consult the data information sheet Preventive Health Program in the Dog section
  • Check your pet daily if they are in a high risk area and remove the ticks as soon as they are noticed, avoid the areas at risk if possible and apply a tick control if you regularly visit these areas.

 

Reference : Lapointe, Catherine. DMV, MSc, Dipl.ACVIM. 2011. Leptospirose et la maladie de Lyme : nouveautés diagnostiques et thérapeutiques. Congrès AMVQ. 2011.