Ticks Are Everywhere, They Spread More Disease Than Previously Suspected


June, 2005

It’s been known for many years that dogs can suffer illness because of tick transmitted Lyme disease, Rocky Mountain spotted fever and a disease called ehrlichiosis.

Ticks may spread more disease than previously thought. For example, it’s been known for many years that dogs can suffer illness because of tick transmitted Lyme disease, Rocky Mountain spotted fever and a disease called ehrlichiosis. Now, you can add Anaplasma phagocytophylum to the list, according Dr. Stephen Levy in Durham, CT. In one study, nearly half of all ticks were carrying this newly identified disease with a very long name,

It seems ticks also carry Bartonella, according to Dr. Ed Breitswerdt, professor of infectious diseases at North Carolina State University College of Veterinary Medicine.

What’s more, veterinarians have only recently learned that one individual tick may carry many disease organisms. It’s conceivable some dogs who are presumably, say diagnosed with Lyme disease are in fact, suffering from a combination of various tick-borne diseases which were all potentially transmitted by a single tick.

That’s bad news. And the news gets worse. It seems there’s an exploding population of ticks spreading all these diseases, according Breitswerdt, who recently earned the World’s Small Animal Veterinary Medical Association Award for Scientific Achievement.

Several factors play a role in the proliferation of ticks. Ticks like the mild winters most of the America has enjoyed in recent years. In fact, some kinds of ticks even ‘wake up’ to catch a meal on mild days in February.

Record populations of white-tailed deer and other wildlife offer the ticks lots of food. As the sprawl of suburbia intersects with forests, more ticks than ever land in backyards. The dogs walk around the neighborhood or visit the local park to further disperse the ticks. But don’t solely blame canines; birds can obviously carry ticks most efficiently. The bottom line is that where there is wildlife, there are likely to be ticks.

Ticks even show up in concrete jungles or in places traditionally considered tick-free such as Southern California. Only a decade ago, veterinarians in Manhattan or San Diego would only rarely see ticks. As people travel with their pets on camping trips or for weekend escapes to places like upstate New York, they return unknowingly with the parasites still sticking on their pets. The ticks drop off in Central Park in New York or Balboa Park in San Diego. Levy says he knows veterinarians who see ticks in the Bronx.

Typically, a female tick can lay a few thousand eggs with hatch into larvae. They most often feed on small mammals before molting into nymphs, which Levy calls “teenage ticks.” Nymphs are smaller versions of the adult ticks which they’ll soon become. Ticks may pick up diseases from any host anywhere in their life cycles, and then pass on disease to their next hosts. Certainly, there are no shortage of small mammals in these urban places (from mice and squirrels to city rats), not to mention the pets who play in the parks.

So far, people don’t seem to be a magnet for these urban tick populations, but if the tick numbers increase, as expected – that will ultimately happen.

Interestingly, cats are bitten by ticks who transmit nasty organisms too. But they don’t seem to get sick. “Learning what it is that cats have going for them would be a great study to do,” says Levy. “Clearly we have so much to learn about tick transmitted diseases.”

Not all dogs get sick either. And no one knows why some dogs are far more affected than others. From a biological perspective, canine species have evolved to survive tick bites for millions of years.

Breitchwerdt says he can only guess it’s a combination of factors which cause some dogs to become very ill, while others suffer only mild symptoms and still others don’t get sick at all. One factor that appears likely is that the more disease organisms a single tick is carrying, the more a dog’s immune system has to deal with. The dog’s general state of physical and maybe even psychological health at the time of being nabbed by the tick is another consideration. The kind of tick doing the biting, how many ticks have bitten the same dog, previous bites by ticks carrying the same organism, the temperature and humidity level at the time of being bitten maybe even the breed may all play a role as well.

Even if not all dogs become sick from being bitten, some do, and some may even die if left untreated. “Of course, protecting against tick diseases is important,” says Dr. Michael Dryden, professor of veterinary parisitology at the college of veterinary medicine at Kansas State University – Manhattan, KS. “The truth is that we can do a much better job at protecting our pets against fleas than we can ticks.”

Dryden says the over-the-counter products are less proven than those available through veterinarians.

Dryden rattles off three choices available through vets: Frontline Plus and K-9 Advantix (both monthly spot on products) and Preventic (a tick collar).

“Certainly, all these products offer some large degree of protection from tick transmitted diseases,” says Dryden. “But they aren’t perfect either.”

Levy says if you live at a place where Lyme disease occurs, significant additional protection is available with a vaccine (called LymeVax).

Also, consider that it’s possible that after living on your pet for a time, ticks may drop off in your yard or even your carpet and infect your family members with the same diseases they may give your dog.