Streptococcal Infection in Cats

Streptococcal canis is commonly found in cats, but in recent years the pathogen Streptococcal equi subsp zooepidemicus, which usually affects horses, has been shown to be present in pigs and dogs with increasing frequency in felines as a result of immunodepression due to Streptococcal canis or other forms of stress. The compromised health of the feline can lead to secondary bacterial infections that can be critical or fatal.

Streptococcal infection, also known as Streptococcal canis, is a commensal and extracellular pathogen common to 10-30% of the feline population within the nasal cavity with chronic upper respiratory infections. However, it can be a severe life-threatening disease if not treated properly. Though first found in horses, it has recently been found in cats also. The pathogen primarily affects cats living in close quarters such as shelters or closed colonies, but it can also affect older, single household cats, or young, breeding females who may pass it on during the birthing process. While highly treatable, it can result in death if not addressed in an aggressive manner.

Symptoms of streptococcus infection may include:

• Severe sinusitis
• Chronic upper respiratory infection
• Skin ulcerations with or without abscesses
• Excessive nasal discharge with color
• Excessive ocular discharge from eyes
• Toxic shock-like syndrome
• Fever
• Cough
• Limping
• Edema
• Pleural effusion (coughing up of phlegm)
• Necrosis of the feet
• Keratitis
• Chlamydia
• Corneal ulceration
• Suspected conjunctivitis
• Cervical lymphadenitis
• Urogenital infection
• Arthritis 
• Cervical lymphadenitis
• Urogenital infections
• Neonatal septicemia
• Bronchopneumonia or pneumonia
• Meningoencephalitis

It is possible that a cat will not exhibit any symptoms and yet is a carrier of the pathogen.

Types

The pathogen is opportunistic and can evolve into several forms.

• Streptococcal canis (S canis)
• Streptococcal equi (S equi )
• Streptococcal zooepidemicus (S zooepidemicus)

Aerosol transmission is not known to be a primary agent in spreading the pathogen. Transmission occurs mainly from contact with infected objects or droplets, or from the reactivation of an existing herpesvirus due to stress.

• Bacterium including herpesvirus in the vagina of queen cats
• Transfer of passive immunity through the colostrum to the kitten
• Compromised umbilical cords
• Wounds (subclinical infection)
• Surgery (subclinical infection)
• Viral infection
• Immunosuppression
• Poor shelter hygiene
• Overcrowding resulting in unmanageable stress 
• Poor air quality
• Poor nutrition
• Environmental stresses

Diagnosis of Streptococcal infection in cats is largely based on overlapping clinical evidence rather than affirmative testing. Such evidence includes colony or shelter health history, planned husbandry or infectious disease protocol changes, individual observation of symptoms and clinical history if any, environmental conditions, and current legal issues concerning the shelter or colony owner (hoarding investigation, liability, etc.). 

Because Streptococcal infection does not typically appear in individual cats, it is up to a shelter, cattery, or colony owner to report to a veterinarian if there has been a persistent outbreak of upper respiratory infections, herpesvirus, or necrosis of the feet. 

A newly developed RT-PCR test, which tests for active and non-active viruses in real time, is also used in diagnosis. Swab samples are taken from the oral cavity, pharynx, bronchial tube, lungs, or wherever lesions have occurred. An individual negative test result will likely rule out any acute infection suspicion, but a positive test result is hard to differentiate from a normal cat’s health. Therefore, a group sampling of 5-10 cats is recommended to establish a firm diagnosis in relation to an expected prevalence of the pathogen within a population. 

Because the RT-PCR test is only recently become widely available to veterinarians, there is no data upon which a doctor can refer to check for acceptable levels, therefore, leaving the doctor to determine a diagnosis mainly based on clinical evidence in cooperation with the honesty of the owner.

Antibiotics 

Early intervention with broad-spectrum antibiotics that contain a gram negative spectrum aimed at secondary infections is essential once infection is suspected. The course of antibiotics should be adjusted as treatment progresses. All newly admitted cats should be examined and treated as well. Overtreatment of antibiotics or the use of a variety of regimens should absolutely be avoided and only administered if the disease is reasonably suspected.

Disinfection 

Repeated and regular rounds of household bleach-based products have proven to be effective at rendering the pathogen inactive. Products such as Virkon® and accelerated hydrogen peroxide reportedly contain detergent properties that other products do not and is, therefore, even more effective. Quaternary ammonium cleansing is also effective at removing the pathogen from the environment. However, it can create toxicity in the cats as well as mimic the symptoms of severe upper respiratory infection.

Quarantine Containment 

Isolation of the affected feline from the healthy population is important for prevention of spreading. In-cage containment is effective if the cage can genuinely be removed from the general population. Removal to a separate room is also valuable and will help with treatment as well. Quarantine containment should be maintained until two weeks after symptoms have completely resolved. 

Following suggested treatment, recovery from Streptococcal infection can occur within 2-3 weeks. However, it is absolutely essential that stress reduction measures be implemented or tightened or else a recurrence of the disease can easily emerge.

Unfortunately, at this time there is no known vaccine to prevent Streptococcal infection in cats. Certain topical treatments and amino acid therapies are being tested, but no conclusive evidence of prevention is apparent yet. 

Keeping the cat as stress-free as possible is a critical element to treating and preventing an outbreak. Stress suppresses the immune system and allows the pathogen to manifest or even to recur after expected recovery. Allowing the cat to stay within the same cage as much as possible helps with reducing stress as does regular spot cleaning instead of broad-based cleaning methods. Socialization, reduction of overcrowding, ample access to healthy food and clean water, and regular grooming also help.

Because the pathogen is activated within the respiratory system, excellent air quality is essential in any shelter or colony environment. Regular use of clean filters along with proper ventilation will help prevent transmission.

Continuous practice of disinfection of the shelter or colony is important to preventing an outbreak and managing its transmission after an outbreak occur.