Actinomycosis Infection in Cats

Actinomycosis infection occurs in bite wounds and results in abscesses, lesions, and other general signs of infection. It can occur in oral, facial, abdominal, and thoracic tissues. 

Actinomycosis is a bacterium that occurs naturally in cats and other animals. Bacteria of the genus Actinomyces occur in the mouth and on teeth surfaces. Infection can occur in bite wounds and is often a component in polymicrobial infections, which are caused by several types of bacteria. Although the bacteria can cause severe symptoms, it is usually not life threatening and has a recovery rate of over 90 percent. 

Actinomycosis symptoms usually present as an infection in or near a bite wound. The infection frequently causes abscesses and lesions localized near the bite wound. The infection and its associated symptoms can spread and may affect the lungs, abdomen, intestinal tract, bones, and spinal cord.

Symptoms Include:

• Infections on face or neck often associated with bite wounds
• Abscesses (most commonly in the mouth, lungs, or gastrointestinal tract)
• Pain
• Fever
• Skin swelling
• Pus or drainage (often with yellow granules)
• Inflammation of abdominal tissues
• Inflammation of bones or spinal vertebrae
• Osteolysis or bone loss
• Trouble walking
• Fluid or pus in the chest cavity
• Trouble breathing
• Coughing or wheezing
• Lethargy

Types

Several forms of Actinomycosis exist. All forms share abscesses as a common symptom. The types of infection include:

• Cervicofacial – occurring in the mouth, jaw, neck, and face
• Abdominal or Pelvic – occurring in abdominal tissues and reproductive organs
• Thoracic – occurring in the chest or lungs
• Generalized – carried by the bloodstream throughout the system

The most common cause of Actinomycosis is a bite wound from another cat. The bacteria that cause the infection occur naturally in the cat’s mouth. Bites, along with scratches and oral wounds, can disrupt the normal balance, causing the bacteria to become infectious. Cats with weakened immune systems, such as those suffering from an immunosuppressive disorder, are at an increased risk of developing the disease. Periodontal disease is also considered to be a risk factor. 

Signs of infection that should prompt a veterinary visit include fever, swelling, redness, itching, hard round lumps, or pus and drainage from wound sites or lesions. Be prepared to discuss your pet’s medical history, the timeline associated with the onset of symptoms, the symptoms you have observed, and whether your cat has recently had a bite or other wound. Your veterinarian may use one of several methods to diagnose Actinomycosis in your cat. They will begin with a physical examination and based on clinical symptoms, preliminary treatment may begin. Actinomycosis is rarely the only bacteria present in infected tissues and is usually treated with common antibiotics, so dosing can start before the exact bacteria are identified.

To confirm the diagnosis, a biochemistry panel or blood testing, bacterial cultures from pus or infected tissues, and imaging tests may all be employed. Cytological testing of fluids or biopsy of tissues should identify the range of bacteria present. Needle or surgical biopsy may be required for testing. X-rays or CT scans can be used to identify the number, location, and size of abscesses, and to look for common symptoms that affect bone structure.

Although Actinomycosis is generally not life threatening, it does require veterinary treatment. The symptoms of a bacterial infection are often enough for a veterinarian to begin treatment before the specific bacteria has been identified. A combination of techniques will be used to treat your cat.

• Drainage of Abscesses – Draining the pus and fluid from abscesses is required to relieve pressure and remove infection. Depending on the size and location of the abscesses, draining may be completed using a needle or by surgical means. Imaging technology may be used to help the veterinarian identify how and where to start the process. This treatment has a low risk of complications; however, surgical methods carry some additional risk.
• Lavage, Debriding, & Tissue Removal – Lavage techniques may be used to wash out abscesses and treat infection directly. If the infection results in tissue death, the veterinarian may need to debride or surgically remove dead tissue.
• Antibiotics – Dosing with antibiotics is needed to kill the bacterial infection. Your pet should be monitored closely for allergic reaction as this is a potential risk with antibiotic treatments. These treatments may continue for months before the infection is completely irradiated.
• Analgesics – This category of painkillers and swelling reducers may be prescribed if your pet is experiencing severe pain or swelling associated with the infection. Correct dosing for the cat’s size will reduce potential side effects.
• Surgery – If abscesses are large, fluid continues to build up, drainage is obstructed, or the disease continues to come back after other treatments, surgical removal of diseased tissues may be required.

Most cats treated for Actinomycosis recover, and the disease is not generally life threatening. A high recurrence in infection has been noted, so thorough treatment and follow-up are needed to ensure a full recovery. Treatment, particularly antibiotic medications, may continue for several months. During this time, monitor the cat closely for signs of further infection, including swelling, itching, redness, fever, or recurrence of lesions. Return visits to the veterinarian for physical examinations and monitoring will be required. Full recovery can be expected in less than four months.