By Matthew Kearns, DVM
The weather warms and the ticks are hungry. There are many new options available for tick control: topical preventative, newer and more effective collars, and, most recently, oral tick preventatives. Also, many of the older products that used to only be available by prescription are now over the counter.
Which is most effective for our pets? Although there are tick-borne diseases (infections and diseases specifically passed through the bite of a tick) in cats, we do not see them in this part of the country. This article will focus on tick-borne diseases in dogs.
Ticks feed during each stage of their life cycles, and it is during feeding that the tick will ingest a variety of bacteria that cause tick-borne diseases. The bacteria is then able to stay in the tick’s gut, the mouthparts or both until it feeds again. Each time a tick feeds, the tick attaches its mouthparts to the host and injects saliva directly into the skin. In the saliva is a sort of topical anesthetic to alter the host’s immune and inflammatory response during feeding.
During feeding, the tick not only ingests blood (its main source of nutrition) but also takes large amounts of fluid. In order not to explode while feeding, the tick is forced to intermittently regurgitate fluid. It is during the injection of saliva and intermittent regurgitation that the tick will transmit bacteria that cause disease.
The big question is how long does a tick need to feed to transmit disease? This very much depends on the tick itself.
Ixodes scapularis, the deer tick, which can carry Borrelia burgdorferi (the bacteria that causes Lyme disease) and Anaplasmosis spp (the bacteria that causes anaplasmosis), will definitely transmit within 72 hours but could be as short as 24 hours.
Dermacentor variabilis, the American dog tick, and Amblyomma americanum, the Lone Star tick, which can carry Rickettsia rickettsii (the bacteria that causes Rocky Mountain spotted fever), will definitely transmit within 48 hours but could be less than 24 hours.
Rhipicephalus sanguineus, the brown dog tick, which can carry Ehrlichia spp (the bacteria that causes Ehrlichiosis), and Babesia spp (the bacteria that causes babesiosis) can be transmitted within 24 hours or less.
First and foremost for almost all of the pet owners that walk through my doors their main concern is not only how effective each product is but also how safe is it to themselves, their family members and other pets in the household. Questions I recommend when choosing a preventative to your dog are:
• Is the tick preventative a repellent or does the tick have to attach and feed to be killed? If so, how long does the tick have to feed before it dies?
• How long does the product work before I need to administer again?
• Do I need to isolate my dog from other pets and members of my family? If so, how long?
• Is this product safe if I have cats in my household?
• Is this product safe if my dog has special health needs such as seizures?
It is nice to have more options, but this also can raise more questions. Consult with your veterinarian at your dog’s annual exam as to which tick preventative is best for them.
Dr. Kearns practices veterinary medicine from his Port Jefferson office.