Joan Merriam: What’s ‘bugging’ your dog? |

Joan Merriam: What’s ‘bugging’ your dog?

Joan Merriam
A sign warning about an area might be infested with ticks. Focus point is on sign with the trees in the back in focus. The weeds towards the bottom are slightly out of focus.
Getty Images/iStockphoto | iStockphoto

You’re just walking back inside after a delightful hike through the woods with your furry pal, and you see something on her fur that looks like a piece of dirt. But then you see it’s moving. It’s not dirt, it’s a tick!

I don’t get creeped out by many bugs and insects, but I don’t think I’m alone when it comes to ticks: there’s just something about a critter that engorges itself on blood and swells to four or five times its original size that makes our skin crawl.

I have no idea why we’re not equally repulsed by the blood-sucking mosquito … yet both of these pests can be equally dangerous, and even deadly, to our canine companions.


Ticks are parasites — and like most parasites, ticks can host a variety of serious infections which they’re more than happy to pass on to whatever victim they happen to bite, including both dogs and humans.

The tick that carries the greatest danger to people and pups alike is the western black-legged tick or deer tick. Today, this tick can be found in 56 of California’s 58 counties.

Thanks to media reports and health warnings that have proliferated in recent years, most people who spend any time outdoors are aware that ticks are the carriers for Lyme disease. In fact, the black-legged tick is the only one of California’s 48 tick species that transmits Lyme.

In the almost-forty years since its discovery, Lyme disease has become the most widespread vector-borne disease in the nation.  (Vectors are organisms that can transmit infectious pathogens between humans, or from animals to humans; vector-borne diseases are human illnesses caused by parasites, viruses and bacteria.) While Lyme is far less serious in dogs than in humans, dogs with the disease can have a number of health issues, including lameness, swollen joints, fever, loss of appetite, swollen lymph glands, and in rare cases, chronic kidney disease.

The good news is that Lyme is treatable with a three- to four-week course of antibiotics, although a dog can be re-infected if bitten by a Lyme-positive tick again after treatment.

An even better option is prevention. Unfortunately, our beautiful Sierra foothills and mountains are among the state’s “hot spots” for Lyme, so most veterinarians recommend dogs have monthly tick-repellent treatments or wear tick collars. Prevention also requires you to be an observant pet parent: if you’ve been walking in woodland areas, check your dog for ticks and remove them right away.

You might also choose to vaccinate your dog against Lyme disease. While there is a very low incidence of side effects from this vaccine, you should always consult with your veterinarian before undertaking a vaccination program.

Finally, allow me to bust a couple of old myths: first, ticks cannot jump. They find their way to you by climbing to the tips of grasses and low-lying shrubs alongside trails or paths, and waiting for a person or animal to brush against them. Another myth is that you or your dog will become infected with Lyme disease immediately after being bitten: in fact, an infected tick must be attached 24 hours or more before the bacterium leaves the tick and enters the human or animal.


Most of us probably think of the buzzing, biting mosquito as more of an annoyance than anything else. To your dog, however, they can be lethal.

Mosquitos carry the parasite responsible for the heartworm infection. Here’s how it goes: mosquitoes become infected with heartworm microfilariae — heartworm offspring — while ingesting a blood meal from an infected animal. These microfilariae mature into larvae inside the mosquito, and once it bites another animal, it deposits the larvae. The larvae travel through the new animal’s bloodstream into the heart and pulmonary vessels, eventually maturing into adult heartworms that reproduce a new set of microfilariae offspring which get transmitted to another mosquito, and the whole pattern begins anew.

Meanwhile, the adult heartworms continue to grow and reproduce inside the animal. The result is a sickening, twisted glob of dozens or even hundreds of worms inside the animal’s heart that ultimately lead to life-threatening cardiac damage.

Treating a heartworm-infected dog isn’t easy or cheap. It involves a series of injections with an arsenic-based product that kills the adult heartworms. But that’s not the hardest part: as the worms begin to die they break into small pieces, which can block the pulmonary vessels and even cause death. If the dog isn’t kept completely quiet, with no exercise whatsoever for several months after the initial treatment, heart failure and death can result. And then there’s the expense: considering pre-treatment blood work, X-rays, and other tests, costs reach $1,000 or more.

The good news is that the disease is easily preventable with a monthly dose of heartworm preventative medication such as Heartgard or Trifexis.

And lest you think heartworm isn’t a problem in our area, think again: as with Lyme, our Sierra region is one of the state’s prime territories for heartworm infection.

So when it comes to protecting your dog from Lyme disease and heartworm, remember the old adage: an ounce of prevention is worth a pound of cure.

Happy spring!

Joan Merriam lives in Nevada County with her Golden Retriever Joey, her Maine Coon cat Indy, and the abiding spirit of her beloved Golden Retriever Casey in whose memory this column is named. You can reach Joan at And if you’re looking for a Golden, be sure to check out Homeward Bound Golden Retriever Rescue .

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