FYI Articles 7

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FYI Articles 7

Preparing for the Avian Flu

By Paul Stewart,DVM

Cause:

H5N1 subtype of influenza virus (type-A orthomyxovirus)

Geographic History:

First identified in 1997, this virus spread over parts of Indonesia.
By 2003, this virus was endemic to Vietnam, Thailand, China, Laos, and Cambodia.
Since then, it has been found in Nigeria, Russia, and most European countries.
All continents are at future risk by natural wildlife migration, except Australia and New Zealand

Species Affected:

Poultry, waterfowl, gulls, and cormorants, people, cats, pigs, horses are susceptible.
More than 100 human cases have occurred since 1997.

Transmission:

Cats contract the virus from eating infected birds (tigers, leopards, and domestic cats have shown susceptibility).

Cats may be capable of transmission to other cats.

Birds contract the virus through direct contact with infected birds or with objects contaminated by an infected bird.

The virus can last longer in damp, dark environments. Virus can be spread through water in pond ducks.

People contract the virus from direct contact with infected birds.

Pandemic is not occurring yet (not person to person), but commonly, influenza viruses can mutate and become adapted to transfer between novel species.

Pathogenesis:

Virus reproduces in the intestine of infected birds.

It is shed in their droppings, saliva, and nasal secretions.

Virulent strains can cause 90-100% mortality within 48 hours in commercial flocks.

Less virulent strains may go undetected.

Up to 50% mortality can occur in people exhibiting clinical disease.

The incidence of less virulent reactions is hard to measure.

Responsible for 200 million deaths in domestic commercial birds.

Symptoms:

In humans: fever, cough, chills, sore throat, muscle aches, eye infections, pneumonia.
In birds: sudden death with acute respiratory +/- gastrointestinal signs are possible.
In cats: fever of unknown origin.

Diagnoses:

Samples will initially go through the health department and state laboratory.

Serum is collected for titers.

A PCR test will likely be available by the time it is here.

Titers to influenza H5N1 may not differentiate between vaccinated and infected.

Valley Animal Hospital may have a change in services offered for human safety reasons (meaning no poultry or waterfowl).

Prevention:

Closed commercial flocks can be housed indoors exclusively.

Water sources should be free of contamination.

Human vaccination will be available once the risk in the US is present. The effectiveness and availability is still unknown.

Tamiflu may hold promise as an antiviral drug in birds and people, however antiviral resistance has been seen in this subtype.

Keep pet birds and cats indoors away from exposure to wildlife and contaminated water sources (maintain a “closed flock”).

Dilute bleach or providone iodine are adequate disinfectants.

Import ban is placed on all birds and bird products being imported from endemic countries.

Hip Dysplasia in Dogs

I. What is it?

Hip dysplasia is a hereditary disease of the coxofemoral (hip) joint
It affects small, medium and large breed dogs, and less commonly can affect cats
Hips are normal at birth but develop abnormally (this is thought to be because the bones grow faster than muscles, resulting in muscles that are not strong enough to hold the hip joint together. This causes the head of the femur to lift up and hit the rim of the acetabulum (socket) and cause distortion.

II. Clinical Signs

Gait abnormalities – the dog will decrease the motion at the hip and instead sway it’s pelvis to advance the limb. This can progress to a hopping gait.
Difficulty or stiffness getting up or lying down.
Muscle atrophy over the rear limbs
Decreased willingness to exercise – owners may complain that the dog “lacks energy”

III. Diagnosis

Ortolani sign on physical exam – manual subluxation of the head of the femur that causes a ‘clunk’ as the femoral head goes back into the hip socket
- Requires sedation in many cases
- An indication of the presence of disease – not the severity of disease
Radiographs – must be taken after two years of age to rule out hip dysplasia according to the Orthopedic Foundation of America (OFA)
- Shallow acetabulum (hip socket)
- Subluxation of the femoral head – sometimes flattening of the femoral head
- Thinning of the acetabular rim and femoral neck
- Bony proliferation – osteophytes

IV. Treatment

Medical Management
- Weight Control – relieve stress on the body; in young animals can use diet to slow bone growth (begin feeding adult diets to affected puppies as young as 3-6 months of age)
- Pain Control – anti-inflammatories such as Rimadyl, Deramaxx, Etogesic and also aspirin. (Many clients will have already been giving their dog aspirin at home!)
- Food Additives – joint supplements such as Cosequin and Glycoflex contain chondroitin and glucosamine. These are thought to stimulate the production of joint fluid, improve cartilage healing and inhibit cartilage breakdown. Essentially helps to restore and maintain a healthier joint
- Physical Therapy – exercise for weight control and increased muscle tone. Low impact exercise such as swimming and slow walks is encouraged.
Surgical Management
- Pubic Symphysiodesis – Must be performed before 5 months of age
- Surgical procedure in which electrocautery is used to fuse a growth plate in the pubic portion of the pelvis
- This fusion causes the pelvis to curve in as it grows, helping the acetabular socket to better cup the femoral head (see image below)
- The patient must be spayed or neutered at the time of the procedure because the problem is hereditary and treated dogs could be misrepresented as dogs free from disease later in life.
- Current studies show minimal to no side effects, and very good success rates. Of approximately 50 dogs treated with procedure, all had normal gaits at 137 weeks post surgery in one study
- Will likely change how hip dysplasia is managed in the future!!
**SEE THE BOTTOM OF THIS ARTICLE FOR PICTURES OF THIS PROCESS**
- Triple Pelvic Osteotomy (TPO) – dogs 6 months to 1 year

Pelvis is cut in three sites, then rotated to better fit the femur

Can NOT be done if significant degenerative changes are seen

4-6 week cage rest following surgery

Most dogs will not show clinical signs of hip dysplasia following surgical healing

Triple Pelvic Osteotomy

Total Hip Replacement (THR) – animals greater than 2 years and 20 kg
- The femoral head is removed and replaced with a metal implant
- Cage rest for 6-8 weeks, with a return to normal function being seen at 8 weeks post surgery
- 50 % of patients will only need one side replaced to have normal activity
- Infection is a relatively common and VERY serious side effect – CANNOT be performed if there is ANY sign of local or systemic infection - this includes skin and ears!!

Total Hip Replacement

Femoral Head/Neck Ostectomy (FHO) – salvage procedure
- Femoral head and neck are removed – this removes the bony contact of the hip joint so pain is eliminated
- Complications include limb shortening, decreased range of motion, gait abnormalities and severe scar tissue formation
- Requires a lot of post-operative physical therapy

V. Key points

Early diagnosis is extremely important because it allows the most opportunities for treatment. Communication with clients about all of their options is key!