bayer cavd site cvbd_home_map bayer_animal_home
bayer roundtable


Ticks and CVBDs

DR. HOSTETLER: Ticks are vectors for many of the most common canine vector-borne diseases. What are the most important considerations for veterinarians in clinical practice with regard to ticks?

DR. BREITSCHWERDT: In some instances, a single tick can transmit more than one organism to a dog, resulting in two diseases, or co-infection. More commonly, we see dogs that have three or four different tick species on them at one time, or at different times, which can result in chronic infections with multiple organisms. That’s where it becomes difficult for the veterinarian in practice. Ten or 15 years ago, we had one pathogen, one disease. Frequently, when an animal presents with clinical signs of a tick-borne disease it’s because the dog already had infection with one or two organisms that it was fighting immunologically. The third organism comes along, and the dog can no longer deal with it.

DR. LORENTZEN: In a recent study, animals were twice as likely to have clinical signs when they were exposed to both Anaplasma and Borrelia organisms.2 The same was true in the paper presented here at the symposium looking at Anaplasma and Ehrlichia co-infections.3 When you have two infectious agents on board, it’s more complicating, more confounding.

DR. BREITSCHWERDT: The study we published in the Journal of Clinical Microbiology several years ago is a good example.4 We were able to demonstrate that 99% of dogs in a North Carolina kennel were infected with multiple pathogens. From an individual EDTA sample, we were able to identify six different organisms from four different genera. Dogs really are well-adapted to not show overt clinical disease when they’re infected with these organisms. But we were asked to come to this kennel because dogs were dying. Many dogs don’t clear these organisms and can carry them around for months or years before the animals demonstrate clinical signs. They can be infected with one organism and do pretty well until they get another tick that transmits another organism.