You might have heard of "cat scratch fever" and wondered what it means. The term may be well known in part because of the popular 1970s Ted Nugent song. In reality, the illness is a bacterial infection called cat scratch disease or bartonellosis.
Bartonellosis is a zoonotic disease, meaning it can affect both humans and other animals. When humans develop bartonellosis, it is usually the result of a bite or scratch from an infected animal.
In cats and dogs, the bacteria usually comes from parasites.
What is Bartonella?
There are several species of bacteria called Bartonella. Blood-sucking external parasites like fleas, ticks, lice, and biting flies are known to be vectors for various Bartonella species. These insects ingest Bartonella when they bite an animal with the bacteria in its bloodstream. This can include cats, dogs, rodents, cattle, and other mammals. Then, they bite another mammal and inject the bacteria into its body.
Cats most commonly become infected with Bartonella from fleas carrying the bacteria (but that can still get it from other vector insects). However, few cats will show symptoms of bartonellosis. They are usually able to fight off the bacteria without ever showing signs. However, while a cat is infected with Bartonella, a bite or scratch from that cat can easily pass on the bacteria to humans. Often, it is the flea dirt (flea feces) on the cat that contains the Bartonella bacteria and gets into the wound.
If you are bitten by a cat, it is very important to seek medical attention. Wounds may become infected with multiple types of bacteria. If you get a minor scratch, be sure to clean it well and watch it closely. Fortunately, most humans can fight off the Bartonella bacteria and only develop a minor, localized skin infection that resolves on its own.
People with compromised immune systems, children, and elderly persons are more likely to develop systemic problems and need treatment. Although bartonellosis is not fatal in humans, it can cause many problems for a person who already has health issues.
In theory, humans may come into contact with Bartonella when bitten by a vector insect. However, cases of humans developing bartonellosis this way are unconfirmed.
How Do Dogs Get Bartonella?
Dogs are most likely to contract Bartonella when bitten by a flea or a tick that carries the bacteria. They may also be able to get it from other vector insects. Dogs are susceptible to different species of the bacteria than those affecting cats. Therefore, it is highly unlikely for a dog to contract Bartonella from a cat scratch or bite.
It is less likely that humans will get infected with the bacteria from a dog bite or scratch (compared with those from a cat). However, it may still technically be possible. It is very important to seek medical attention for yourself if you get a dog bite or a serious scratch. For minor dog scratches, clean the area well and watch it closely.
Not all dogs will become sick when they contract Bartonella. However, dogs are more likely to develop symptoms than cats.
Fortunately, bartonellosis is not considered highly common in dogs.
Signs of Bartonellosis in Dogs
There are a number of signs associated with bartonellosis in dogs. Not all dogs will show the same symptoms. Different Bartonella species can cause different signs. Some dogs will never even become sick. The following signs are most often associated with bartonellosis in dogs:
- Weight loss
- Loss of appetite
- Trouble breathing/abnormal breathing
- Lameness and/or weakness (may be on and off)
- Bone or joint pain
- Dermatitis and/or skin lesions
- Enlarged lymph nodes (may look like swelling in neck area, armpits, or backs of knees)
- Jaundice (icterus; yellowing of skin, eyes, mucous membranes)
- Enlarged abdomen
- Heart arrhythmia
Some dogs with bartonellosis can develop endocarditis, which is an infection in the lining of the heart that can involve the heart valves as well.
Dogs with bartonellosis may also have concurrent infections (such as other tick-bourne diseases).
How Vets Diagnose Bartonellosis
If your dog is showing signs of bartonellosis or any other illness, it is important to go to your veterinarian. After completing a physical examination, your vet will probably recommend a number of lab tests to determine the cause of your dog's illness. At the very least, your vet will do a complete blood count to measure and count the blood cells and a blood chemistry to assess organ health and metabolic function. If your vet suspects bartonellosis, a blood culture and other diagnostic procedures will be needed. Your vet will also want to check for concurrent infections and other diseases.
Bartonellosis Treatment Options for Dogs
Antibiotic therapy is the main treatment for bartonellosis in dogs. Treatment protocols vary depending on many factors. Your dog will most likely need to take several different types of antibiotics for weeks to months. If your dog has developed any secondary conditions, your vet might recommend other treatments.
If your veterinarian has diagnosed bartonellosis in your dog and prescribed medications, it is essential that you give all medications precisely as directed. Compliance with the treatment recommendations is an extremely important part of your dog's recovery.
If your dog has a serious secondary problem or is not responding to treatments, your vet may refer you to a veterinary specialist for a second opinion. This may also involve advanced diagnostics and/or treatments.
Bartonellosis itself is not usually fatal in dogs, but severity varies from dog to dog. The secondary issues caused by the infection can lead to death. Early diagnosis and treatment are key to your dog's survival.
How to Prevent Exposure to the Bartonella Bacteria
Check your dog for signs of fleas and ticks regularly. Talk to your veterinarian about safe and effective parasite prevention for your dog. Over-the-counter products and natural remedies are rarely effective and may even harm your dog.
It is also important that you protect yourself and other people from Bartonella. Be sure all pets in the home are on parasite prevention. Train your dog well and take steps to prevent dog bites and scratches. Be sure to seek medical attention for any bites and scratches that do occur.