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Giardia: A Parasite of Many Species

If you have a friend who camps or fishes, you may have heard that they had been infected with Giardia. Or your veterinarian may have told you that your cat or dog had Giardia. In either case, you probably wondered, can I catch it as well?

Giardia is a protozoan parasite (one-celled organism) that can infect a variety of species, including pets and people. The human form of Giardia really likes people, the canine form likes dogs, the feline form likes cats, and the ruminant form likes cows and sheep. But it is possible for any of the forms to infect any of the other species.

In an animal or a person, Giardia lives in the intestinal tract. It may cause no symptoms, especially at first, but with time and as the organism becomes more numerous as it propagates, diarrhea commonly occurs. Some people may have more long standing or severe disease; then the symptoms can also include abdominal cramping, nausea, vomiting, loss of appetite, and weight loss. Pets also get diarrhea when infected, but they tend to get diagnosed faster as it is common to do regular fecal testing in veterinary medicine.

Giardia cysts are passed in the feces of infected animals and people. These cysts are resistant to environmental extremes, and thus can live in feces or fecal contaminated soil, surfaces, and especially water, for a long time.

Pets and people are usually exposed from contaminated sources in the environment. Giardia is a common cause of recreational water illness, from pools, water parks, water play areas, hot tubs, lakes, rivers, ponds, streams, and oceans. Pets and people swallowing even a small amount of water can become infected. You share the water, and the germs in it, with every person or animal who enters that water. The infective Giardia cysts can also be present on other surfaces contaminated with feces such as bathroom fixtures, changing tables, diaper pails, and toys. Uncooked, fresh produce can be contaminated as well.

Luckily, Giardia is easily diagnosed in veterinary medicine. There are two tests commonly performed: a microscope test call an “ova and parasite” (O&P) where the technician looks for the presence of the parasite in a solution made from the feces and then centrifuged. The other test also uses a stool sample, but uses a more sophisticated method to check for any DNA of the Giardia parasite.

Treatment is usually very rewarding. Drugs commonly used are metronidazole or fenbendazole, although in stubborn cases they may be used at the same time.

What can you do to prevent infection in the first place? Have your pets’ stool checked regularly for parasites (at least twice yearly). Practice strict hygiene, cleaning surfaces that could become contaminated by stool. Wash your hands after going to the bathroom, and insist your children do as well. Every day, place any dog and cat feces from your property into plastic bags that will go to a landfill. If you have a pool, keep it well maintained, don’t allow any person or pet in the pool if they have diarrhea, and have everyone shower (with soap) before entering the pool. Don’t allow children to defecate while in the pool. Don’t swallow any water when you are in a pool or any other type of recreational water. Wash all produce well before consuming.

Giardia is a common parasite. Your veterinarian can check your pets for Giardia by performing a stool test, and treat if necessary. You can prevent your family from being infected by some common sense, good hygiene practices.

Sources:

Companion Animal Parasite Council 
Centers for Disease Control and Prevention 

Fleas, the Frustrating Pest

Consider the following scenario: You arrive home from a long flight from a wonderful, two-week vacation. As you drive home, you remind yourself the boarding kennel is already closed and you have to wait until tomorrow to pick up your dog, Max. You finally walk in the front door, happy to be home. As you walk across the carpet you feel a tingling sensation on your legs and when you look down, you see your white socks now look gray. FLEAS!!

Some people’s reaction to the above would be to banish the dog from the house and to call the exterminator. Both reactions would be wrong – neither would help to rid the house of fleas. Why? In order to appreciate, you must have a basic understanding of the different stages of fleas, such as their life cycle, and know which chemicals kills which stages, if any!

There are four stages of a flea’s life: egg, larva, pupa, adult. Only adult fleas are on the pet, the other stages are in the environment. The female fleas on the dog lay eggs that roll off onto the carpet, bedding, floors, grass, etc. In one to six days, the eggs hatch to larvae that can crawl. In five to 11 days, the larvae change to pupae. Unfortunately, there is no chemical or substance that can kill flea pupae other than fire. Even worse, the pupae have the ability to go into “suspended animation” and just stay in this state until a host appears. We know this state can last at least one year. Once a host comes close, certain stimuli cause the pupae to hatch to adults that immediately hop onto the host, which in this case, is either your pet or you!

Should you banish “Max” to the backyard? No!! If there is no pet in the house, the fleas in the house will simply go to you to live and feed. You need Max to act as “bait”. A good adult flea treatment should be used on Max. Your veterinarian can advise you on such products. Since you have been gone for two weeks, all the fleas in the house (before you entered) were in the pupae stage. Therefore, any chemical an exterminator would use would be useless. Once a host enters the area, the fleas immediately hatch and go to the host, so any residual chemical in the carpet is also useless, the fleas aren’t exposed long enough to be killed. Premise sprays take 36 to 48 hours to kill fleas. You have to treat adult fleas by treating the pet. The best flea control involves treating all the stages possible and stopping egg production. Drugs that kill eggs and larvae are added to some adult topical treatments or are available separately. Your veterinarian is the best source of information on integrated flea treatment.

Flea Preventative Medications: Oral vs. Topical

Fleas are not only a source of irritation and frustration, but they also pose a serious health threat to animals. These tiny external parasites can carry a variety of diseases, including bubonic plague, and severe infestations may cause deadly levels of blood loss in very small or young pets, according to national animal welfare organizations. Owners must therefore employ every preventative measure to keep these creatures off of their beloved pets, including the use of topical or oral medications.

The first line of defense is prevention. Prevention can be as simple as removing fleas and their eggs from your household by cleaning, vacuuming, and applying pet-safe pesticides to the yard. Keeping your grass mowed and removing excess sources of shade can rob fleas of their preferred environmental conditions, discouraging them from breeding in the yard. But no matter how scrupulously you keep your indoor and outdoor environments under control, at some point your pet is likely to need some form of flea treatment. These treatments may take topical (“spot-on”) or oral forms.

Topical Medications

Topical or “spot-on” flea treatments are readily accessible to pet owners. These products can be highly effective at eliminating flea infestations or preventing new ones from occurring. Veterinary organizations point out, however, that while approved flea preventatives are generally considered safe, owners must follow the instructions on the label with great care to prevent a possible toxic or otherwise adverse reaction to the chemicals in the product. Animal welfare organizations also warn owners never to give cat flea treatments to their dogs or vice versa, because the results could prove fatal.

Oral Medications

Oral flea medications also have their pros and cons. In addition to topical treatments widely available, veterinary clinics also prescribe oral products such as Comfortis. Typically, regular monthly doses of such drugs aim to kill fleas before they have a chance to lay eggs, stopping infestations before they start. You may find that the oral delivery method creates less of a mess than the topical route, while also eliminating concerns over skin reactions to the active ingredients. But oral medications may also cost more than topical treatments, and prescriptions will need to be refilled regularly to maintain constant protection.

Sources:

AVMA, “Flea and Tick Treatments: EPA’s Investigation of Spot-On.”

Comfortis, “Controlling Fleas in Your Home.”

Cruz, Bernadine, DVM; Mesenhowski, Shannon, DVM, “Save Use of Flea and Tick Preventative Products.” AVMA, Dec 2012.

Creepy, Crawly Critters

There are many parasites we need be concerned about that can affect our pets. Ticks are one of the most common and frightful. Most people shudder just at the thought of a tick, let alone finding one on their pet or in their house. Unfortunately, the people who study these things tell us we should expect a large increase in the numbers of ticks. Global warming and milder winters may be contributing to the surge of ticks, even to areas they may not have populated before.

Ticks are found worldwide, but tend to be found more in areas with warm, humid climates. They are parasites that attach to mammals, birds, and occasionally reptiles and amphibians, and suck blood from their host.

There are four stages in the tick life cycle; each tick requires three hosts and takes at least one year to complete the cycle. Each female tick can lay up to 3,000 eggs in the environment. Egg hatches and forms a larva which is very small, the size of a head of a pin, and it attaches usually to a small mammal or bird. Once it is done feeding, it detaches, and molts in the environment to the next stage, the nymph. The nymph then finds another, usually larger host to attach to and suck blood. Once it is done, it detaches, and matures into the adult tick. Adult ticks then need to find a suitable host. They climb to the top of long grass, bushes, or other plants, and wait for a dog, cat, deer, cow, or any other animal to brush up against it. Once on its host, it again bites the skin and feeds by drinking blood.

There are many different species of ticks, but most, if not all, can carry diseases they can give to their host. Common tick borne diseases are Lyme disease, Babesia, Ehrlichia, Anaplasmosis, tularemia, and Rocky Mountain Spotted Fever. All of these diseases can affect dogs, and many can occur in cats, people, and other species. The eggs can be infected inside the female tick, so even the tiny larval tick can be infectious.

There are some things you can do to try to prevent ticks in your house and yard. If you live in a more rural area, guinea fowl are great tick exterminators. Just two birds can clear two acres in one year. You can reduce the tick habitat by removing the leaf litter and clearing tall grass and brush. Discourage any wildlife from entering your yard with fences. If you live near woods, create a three foot wide barrier at the edge of your lawn with wood chips or gravel; ticks can’t crawl across this. You should check your pets daily and remove any ticks you find.

We have three chemicals that we use on pets that will kill ticks, but only one can be used on cats. Fipronil, found in Frontline, can be used on dogs and cats. Permethrin has been used on dogs, but is very toxic to cats, you need to read labels and if it says “for dogs only”, do not apply it to a cat as it will likely be lethal. Amitraz will also kill ticks. It is available for dogs only, in the form of a collar called Preventic. This is very effective but you must make sure the dog can’t eat the collar. A new product by Merial called Certifect is a combination of fipronil and a low dose of amitraz. This is for dogs only, is applied topically once monthly, and is very effective.

You should talk to your veterinarian about the tick diseases in your area. There is a test kit your veterinarian can use in the clinic that will test for Lyme disease, Anaplasmosis, and Ehrlichia at the same time your dog gets its annual heartworm test. Your veterinarian can also discuss any treatments or preventatives from which your pet may benefit.