Giardiasis

Giardiasis is an intestinal infection caused by a parasitic protozoan (single celled organism) called Giardia lamblia. These protozoans are found in the intestines of many animals, including dogs and humans. This microscopic parasite clings to the surface of the intestine, or floats free in the mucous lining the intestine. Veterinary research documents suggest that 5% to 10% of all dogs in North America have giardiasis at any given time. Surveys also show that about 14% of the adult dog population and over 30% of dogs under one year of age were infected at some point during their life, and thus contributed to passing along this intestinal infection to other dogs. Another Vet research article I found suggests that 100% of kennel dogs, 50% of pups, and 10% of well-cared for dogs carry giardia.

How can my dog contract Giardia?

Giardia lives and reproduces in the small intestine of host animals. Giardia trophozoites, the free living stage of the organism, form infective cysts that are passed out in the feces. If the cysts are present in a wet or damp environment they can survive in a viable state for a few weeks to several months. Giardia infections are transmitted via ingestion of trophozoites or cysts in contaminated water or food. If a giardia cyst is ingested, the cyst wall is broken down during the digestive process and the trophozoite stage begins to colonize the upper small intestine. Transmission also occurs by direct contact, especially with asymptomatic carriers. More recently, giardiasis has also been recognized as being able to be sexually transmitted. Giardia is so prevalent throughout North America because it is highly contagious. The ingestion of as few as one or more giardia cysts may cause the disease, as contrasted to most bacterial illnesses where hundreds to thousands of organisms must be consumed to produce illness.

Giardia causes its unpleasant effects on the body not by invading the tissues, but simply by being in the way. It multiplies to the point where it sort of paves the lining of the intestine and blocks normal digestion (malabsorption). This causes only partially digested food to get lower in the digestive

What are the clinical signs associated with infection?

The trophozoites divide to produce a large population, then they begin to interfere with the absorption of food. Clinical signs range from none in asymptomatic carriers, to mild recurring diarrhea consisting of soft, light-colored stools, to acute explosive diarrhea in severe cases. Other signs associated with giardiasis are weight loss, listlessness, fatigue, mucus in the stool, and anorexia. These signs are also associated with other diseases of the intestinal tract, and are not specific to giardiasis. These signs, together with the beginning of cyst shedding, begin about one week post-infection. There may be additional signs of large intestinal irritation, such as straining and even small amounts of blood in the feces. Usually the blood picture of affected animals is normal, though occasionally there is a slight increase in the number of white blood cells and mild anemia. Without treatment, the condition may continue, either chronically or intermittently, for weeks or months.

How can I be sure my dog has Giardia?

Diagnosing giardia is not easy. Diagnosis can be done in one of two ways: via fecal sample by a Vet or via educated evaluation of clinical findings by the breeder/owner or the Vet. Via fecal sample is not straightforward. Even when a flare is at it's worst, the cysts will not be shedding in every single stool. Therefore, a negative report does not rule out giardia. The most thorough way to assess is to collect a sample from every single stool produced for 48 to 72 hours and have a Vet examine it using the giardia test kit.

Hip Dysplasia

The term “dysplasia” means “abnormal growth” thus “hip dysplasia” means abnormal growth or development of the hips. Hip dysplasia occurs during the growing phase of a puppy, usually a large breed puppy, and essentially refers to a poor fit of “ball and socket” nature of the hip. The normal hip consists of femoral head (which is round like a ball and connects the femur to the pelvis) as well as the acetabulum (the socket of the pelvis), plus the fibrous joint capsule and lubricating fluid that make up the joint. The bones (femoral head and acetabulum) are coated with smooth cartilage so that motion is nearly frictionless and the bones glide smoothly across each other’s surface.

Do not expect a dog with dysplasia (or any other chronically painful condition for that matter) to cry or whine in pain. Instead discomfort is shown with reduced activity, difficulty rising or lying down or going up stairs. A characteristic swivel of the hips is seen from behind and classically stairs are taken in a “bunny hop” fashion.

The primary cause of hip dysplasia is genetic but inheritance of this trait is not as simple as a dominance/recessive relationship like we study in high school biology. Normal dogs can breed and yield dysplastic offspring as the condition may skip generations. Until a test based on the actual DNA can be developed, the best we can do to prevent this disease is to breed only dogs with normal hips.

How Can I Find out if My Dog has Hip Dysplasia?

There are two reasons to pursue testing: to explain a dog’s discomfort/rear weakness or to screen a dog for breeding purposes. If a dog is not going to be bred and is not in any apparent discomfort, there may be no benefit to looking at the conformation of the bones in a radiograph except possibly to look back at a future time to get a sense for progression of bony changes.

The first step in diagnosis is an examination. Your veterinarian will likely extend the dog’s hind leg backward to check for pain. (Hip dysplasia causes pain on hip extension.) The dog may be asked to walk around to possibly demonstrate the hip swivel. Another test involves having the dog lie on its back with a hind leg perpendicular to the body. As the leg is moved away from perpendicular to the body, a dysplastic hip will generate a “pop” as the femoral head slips to the center of the acetabulum. This “pop,” which can be felt if one’s hand is resting on the hip during the exercise is called an “Ortolani sign.” You may hear this term used as hip dysplasia is discussed.

To find out for sure about dysplasia, radiographs are necessary and this generally involves some sort of sedation to minimized the patient’s discomfort as their hips are properly positioned for the picture. Sedation also helps the veterinary team control the dog’s position better so they can minimize the number of radiographs needed in order to get one good diagnostic view. The classical view is called a “VD Pelvic View” where the dog is held on its back with its legs straight out. This shows the seating of the two femoral heads as well as any bony changes indicating arthritis. This is the view required by the Orthopedic Foundation for Animals for registration.

What is OFA Registration?

When purchasing a puppy, particularly one of a larger breed, often the parents will be listed as “OFA Good” or “OFA Excellent.” What this means is that the breeder has had the hips of the parent dogs certified by the Orthopedic Foundation for Animals. The OFA is an organization with a goal of reducing the incidence of hip dysplasia (though now it is also possible to obtain certification for elbows, thyroid function, and other issues). The idea here is that a dog for breeding can have radiographs taken at age 24 months. The radiographs are sent to the OFA for review by several independent radiologists where they are graded. Hips that are rated as “good” or “excellent” receive a registration number. Offspring of OFA certified parents would be less likely to develop dysplasia themselves, however, it is important to realize that a dog with excellent hips at age 2 may not have such excellent hips at age 5, 7, or 10. OFA certification is no guarantee that a dog will not develop hip dysplasia symptoms in the future and does not guarantee that the offspring will not develop hip dysplasia.

What is PennHip Registration?

Many people with potential breeding dogs do not want to have to wait two years for OFA registration. The University of Pennsylvania Hip Improvement Plan, developed by Dr. Gail Smith, allows for another way to predict if a dog will develop hip dypslasia. For PennHip certification, the veterinarian taking the radiographs must receive special training and special equipment is necessary. The pet is anesthetized and two radiographs are taken: one with the femoral heads “compressed” (pushed into the acetabula as far as they will go) and one with the femoral heads “distracted” (pulled out of the acetabula as far as they will go). A measurement called a “distraction index” is calculated from these radiographs, with the idea being that a tighter fitting hip (one allowing less distraction) is less likely to develop dysplasia. Each dog breed has a different range of distraction indices that are considered acceptable. Puppies can be certified as young as 16 weeks of age with this system.