Pesky pet parasites

Pesky pet parasites (May 29, 2014)

Q: Considering the cold, snowy winter we just had, can pet owners look forward to any relief this year in dealing with fleas, ticks and other parasites?

A: Ahh, if only! Cold winters may reduce the parasite population, but these hardy and horrifying pests always make a comeback. So knowing your prevention options is as important as ever.

External parasites include fleas, ticks, mosquitoes and sarcoptic mange. Fleas can cause maddening allergic skin reactions and transmit a scary variety of viral and bacterial diseases (as well as some internal parasites) to both animals and humans. For example, bartonellosis, transmitted by fleas, is a serious chronic disease in people, causing fatigue and muscle pain. It’s very difficult to diagnose — at this time, just one lab has developed a diagnostic test.

Deer ticks are notorious for spreading Lyme disease, but ticks also carry a wide range of serious illnesses, many of which are still unknown. In the Midwest, a new tick-borne disease was diagnosed, causing high fever in some humans and even death.

Heartworm is a life-threatening parasitical illness spread by mosquitoes to both dogs and cats. Sarcoptic mange can spread from wild animals (such as foxes) to dogs and causes severe itching. It is also potentially contagious to people. Sarcoptic mange may go unrecognized by your veterinarian or be misdiagnosed, but it can be easily treated and cured. 
The companies making and marketing parasite control and prevention products are always working on new formulas. Dog and cat owners have multiple choices between topical (“spot-on”) and orally administered products. So how do you make the best choice for your pets?

It’s important to know that some prescription topical flea and tick products also prevent heartworm and sarcoptes, as well as intestinal parasites. Others don’t. Depending on your prevention choices, you may need a combination of products — for example, a spot-on ointment that kills adult fleas, disrupts the flea life cycle and kills ticks but doesn’t repel or kill mosquitoes will need to be combined with a heartworm prevention pill.

There’s also the choice between prescription and over-the-counter products. Prescription products typically have the newest and most potent ingredients, so they may be more effective.

But the patent on fipronil, the primary active ingredient in topical flea and tick ointment Frontline Plus, has expired—which means that non-prescription products may now use it. Does that mean they’ll be as effective as the prescription formulations? We don’t really know yet.

Also, be aware that products intended for cats are not interchangeable with those made for dogs. What’s safe for a dog could be an overdose for a cat, with critical consequences. We do recommend a heartworm preventative treatment for both indoor and outdoor cats. Just because your kitty doesn’t go outside doesn’t mean mosquitoes can’t come in.

These products are designed to dispatch parasites while minimizing toxicity to us and our animals, but they’re not entirely risk-free. There have been instances of pets having allergic reactions, some serious. And pet owners should read the fine print to learn precautions for safe use (such as washing hands after coming in contact with topical ointments).
Giardia is a common intestinal parasite. The only way to test for it is fecal analysis by your veterinarian. Since some animals with giardia may not have overt symptoms, stool analysis every six months is recommended to check for evidence of this and other internal parasites.

Some parasites — including hookworm, roundworm and giardia — are potentially contagious to people. I actually had a case at my office several years ago of a child infected with roundworm. The source of the infection remained a mystery, but it could have come from a playground sandbox, since outside cats sometimes use children’s sandboxes as litter boxes, and roundworms can remain in the sand for a very long time.

Ultimately, your veterinarian is your best bet for answering all your questions and making the smartest, safest and most effective choices to protect your pets against parasites.