Vol. XIII, Week 3 Jan 23, 2023


All Issues

Genetic Test for Risk of ACL Rupture

The University of Wisconsin Vet School has published findings that show that "62% of the risk [of ACL] is genetic and 38 percent is environmental. 

The canine cranial cruciate ligament is much like a human’s anterior cruciate ligament (ACL), acting as an important stabilizer of the knee joint in both species. Although any dog can rupture the ligament, it is uncommon to happen through injury alone. Rather, genetics play an essential role in the degeneration of the cruciate ligament, increasing the risk of a rupture.

If you want to learn whether your Labrador Retriever is at high risk for developing a cruciate ligament tear, contact the Comparative Genetics and Orthopaedic Laboratory at genetics@vetmed.wisc.edu. Testing costs $250 and will take four to six weeks for results.

The risks of brucellosis

Maddie Hayward, DVM has published an excellent -- and heart rendering -- story about her two-year old lab who contracted brucellosis and was asymptomatic (no symptoms). Brucellosis is a bacterial, zoontic disease, meaning it can not only be transferred to dogs, but also to humans.

After doing a lot of research, she concluded that her dog had contracted the disease in her environment.

Aspen’s Story: Our Family's Experience with Brucella canis
By Dr. Maddie Hayward, DVM
As I draw up the euthanasia solution in a syringe, I hear my four-year-old daughter say, “I love you Aspen,” as she goes to pet our family’s two-year-old yellow lab, Aspen. At that moment, something inside me shatters. My daughter does not know what is going to come next. Neither does Aspen. Over the past 10 years of being a small animal veterinarian, I have performed hundreds of euthanasias. This is one of the hardest parts of my job. Euthanasia is when I humanely end an animal’s life. A vast majority of the time the animal is suffering. Their quality of life is poor, and I can end suffering by performing this act. Today, this is not the case. When I look into Aspen’s dark brown, forgiving eyes, I see life. I see love. I see trust. I see a completely healthy dog in her prime that should live for 10 to 12 more years. But she is not healthy. She has Brucella canis.
Brucellosis is a bacterial disease that is zoonotic, which means it can be transferred between animals and humans. There are different species of Brucella that affect different animals. Dogs are a significant host of Brucella canis. There has been a large misconception that this disease mainly affects dogs from large breeding kennels and shelters. That is no longer the case. Family owned dogs can get Brucella. Spayed and neutered dogs get Brucella. Screening is mostly performed on breeding or shelter animals; that is why it has been associated with these dogs. This is a disease that can be transmitted in reproductive tissues and fluids, which is why it has previously been associated with large populations of intact animals, or animals that have not been spayed or neutered. But it can also be transmitted in urine, feces, and secretions from the nose and eyes. Contaminated urine can last in the environment for months in the right conditions. Aspen most likely became infected through urine. At some point in the last two years, she most likely came in contact with contaminated grass.
Many infected dogs are asymptomatic. Like Aspen, they do not look or feel sick. They can transmit the disease even though they appear healthy. Other dogs do get sick. Dogs that are intact show the most obvious clinical signs. Females can have abortions and stillbirths. They can have trouble getting pregnant. Males may have a difficult time getting females pregnant. This does not happen all the time though. Clinical signs can be nonspecific and may include stiffness, lameness, or back pain. Dogs can also present with eye or skin infections. They may spontaneously recover or have chronic clinical signs. Once recovered, they will still transmit Brucella. The dog can appear completely healthy but still transmit the disease.
This disease terrifies me. It makes me feel helpless. With every other disease, there’s always something I can do to extend or improve quality of life. I can provide pain relief. I can treat heart disease. I can treat kidney disease. I can treat cancer to an extent. If I do not have the equipment or ability to treat, I can refer to someone who does. With Brucella canis, I feel like it’s a death sentence. The “treatment” is a minimum of four to eight weeks of combined antibiotic therapy. That’s if the pet can tolerate the high doses of medication. These antibiotics may cause kidney failure among other illnesses. These antibiotics are not cheap. The goal of treatment is to push the bacteria intracellularly and to get the dog to test negative. Some dogs will never test negative, even after months or years of antibiotics. Brucella does not go away. It is aways there in the body and will eventually come back. Relapse is common. Routine screening needs to be done to detect when it does. Ideally blood and urine testing should be performed every three months for the rest of the dog’s life. The goal is to catch it and treat with antibiotics again before it infects humans or other dogs.
Humans infected by Brucella canis can show a wide variety of clinical signs. They can be asymptomatic or show nonspecific flu-like clinical signs. This may include fever, sweats, malaise, headache, pain in muscles, joints or back, and fatigue among other things. Humans can also show nonspecific gastrointestinal signs such as anorexia, vomiting, diarrhea, or constipation. These signs and symptoms can wax and wane. They may spontaneously resolve, persist for longer periods of time, never go away, or reoccur. Long-term clinical signs may include recurrent fevers, arthritis, swelling of the testicle and scrotum area, swelling of the heart, neurologic symptoms, chronic fatigue, depression, and swelling of the spleen or liver. In humans this disease can look like anything. It is difficult to diagnose, and testing may not be accurate. Treatment includes long-term antibiotic therapy and relapses may occur. It is likely that Brucella canis is underdiagnosed in humans.
I love Labrador Retrievers, especially yellow ones. I was raised with yellow labs and have always had one in my life. Before getting Aspen, I looked for her for years. I found a reputable breeder that bred healthy, beautiful puppies. I was put on their waitlist. When Aspen was born, I was there. I helped deliver her litter. I picked her on day one. My family watched and visited her as she grew. We saw her open her eyes and her grow into a curious, intelligent, playful puppy. I held her in my arms when we drove home. She did not sleep like she was supposed to. She went between by children in their car seats and played with them. She immediately became part of our family. It took forever to house-train her. I was up for months taking her out every few hours at night to go to the bathroom. She came to work with me and stayed in the office while I worked. Aspen was our family’s sock thief. She had a gift of finding them and carrying them around. She was full of life, and we loved her so much.
We wouldn’t have known Aspen had Brucella canis had we not decided to breed her. She was never sick. Prior to breeding, genetic testing was done in addition to OFA hip, elbow, and eye certifications. She passed all of these. Lastly, I did a Brucella canis screen as a precaution because the breeder that owned the male I had decided to breed Aspen to required it. I personally have not done many of these screening tests. It is not something that clients approve or is routinely elected prior to people breeding dogs. Her test came back positive. I initially thought there was a lab error. There can be false positives. I repeated the test as well as performed three additional ones. They all came back positive. I did a urine culture and that was negative. That meant that Aspen had the disease and was a carrier of it. She was not at the point where she was transmitting it through her urine. That was the silver lining. Our other family dog tested negative. Aspen was asymptomatic with Brucella canis but was not likely actively shedding the disease.
Once finding out that Aspen had Brucella, I tried to track down where she contracted the disease. Everyone I spoke with said that she likely was born with it and came to us already infected. I reached out to the breeder for an answer. The breeder never had had any dogs test positive for Brucella canis. Once finding out about Aspen she very responsibly tested all her breeding dogs, including Aspen’s parents. All the tests came back negative. Aspen did not come to me with this disease. That means it is something that was acquired once she was with us. We live on five fenced acres in semi-rural Montana, 20 minutes south of Missoula. I have never taken Aspen to the dog park. She has never been boarded or groomed. She does not go to doggy day care. She is not around other dogs. She has never been around an intact or shelter animal. She comes to work with me daily but does not leave my office and has a separate yard. She should not have been at a high risk for getting this disease, but she was exposed somewhere. This leads to the question, how prevalent is Brucella canis? I can tell you with confidence that it is underdiagnosed and is actively spreading.
Brucella canis is a reportable disease. Positive tests are required to be reported to the state veterinarian. I spoke with several state veterinarians about Aspen and got the same recommendation: euthanasia. In Montana, euthanasia is not required, but recommended. In some states it is required. Dogs that are not euthanized need to be quarantined at home for life. They can never leave. No children, elderly adults, or immunocompromised individuals can be around the dog. They should have limited human exposure. The dog cannot come into contact with other dogs. Plastic gloves should be worn and precautions should be taken when picking up feces or cleaning other bodily fluids. The dog needs to have routine blood and urine testing for Brucella canis. The dog needs to be on antibiotics until it tests negative. Antibiotics will be needed whenever it tests positive again and, at some point, that will happen.
I chose to euthanize my own young, apparently healthy dog. It was the hardest thing I never wanted to do. This is not a disease that goes away, in dogs or humans. It’s something that they may always have. My daughter still asks where Aspen is. I find myself calling our other dog and saying Aspen’s name instead. When I let our other dog in from outside, I keep the door open and look for a dog that I will never see again. She was always beside me. She was my companion. She was my children’s best friend. This was supposed to be the dog my kids grew up with. Instead, Aspen is no longer with us, and we are all taking three weeks of multiple prophylactic antibiotics. Our entire family has had blood drawn and is waiting on blood culture results. The risk to humans is real.
The reason I share my story is because I hope that it will raise both public and veterinary awareness about Brucella canis. If I can prevent one person or family from going through what we are, I would gladly do so. Brucella canis screening is an inexpensive blood test that is sent out to a veterinary laboratory. Results are received within a week. If you are going to bring a puppy into your home, please make sure the parents have been screened for Brucella canis. If you bring a dog into your home, please have them screened prior to exposing your family and other dogs. Ideally two tests 30 days apart should be performed. If you are breeding dogs, please screen every animal prior to breeding. Testing should be repeated every 6 to 12 months for breeding dogs. If you are a veterinarian, please recommend screening these animals. This disease is more prevalent than we think. Most dogs are asymptomatic, and we are not testing appropriately.

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Week 03

This week’s newsletter includes results from:

Bluebonnet Retriever Club (BbtRC) - see full results
Jacksonville Retriever Club (JRC) - see full results
Phoenix Retriever Club (PxRC) - see full results
San Jose Retriever Club (SJRC) - see full results
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