Health Spotlight: Mycoplasma felis

Health Spotlight: Mycoplasma felis

A friend posted recently that her beloved kitty had been diagnosed with this, and wondered what it meant. Naturally, I had to research it! Here's what I found:

What is Mycoplasma felis?

Mycoplasma are microscopic bacterial plant life (flora) that live everywhere in nature. This includes in humans, plants, insects, and in your cat's nasal and respiratory passages. They are thought to be the smallest organisms that can grow independently. A few can worsen infections in a cat's eyes or lower respiratory tracts. Others are suspected culprits in arthritis or urinogenitary tract infections.

These bacteria are anaerobic; that is to say, they do not require oxygen to live, grow, and reproduce. They can easily change shape because they do not have a typical cell wall. This makes them able to easily travel to various areas of the body.

Mycoplasma felis, or M. felis, is only one type of these bacteria. Others are M. gataea and M. feliminutum. There is another type of bacteria called M. hemofelis, which is a very different pathogen of the blood that affects your cat's ability to produce white blood cells. It is not the same as M. felis.

What Causes Mycoplasma felis?

Since it is a type of bacteria found everywhere, a more accurate question would be: What does Mycoplasma felis cause? M. felis is one of many possible bacteria that can worsen feline conditions such as:

• Conjunctivitis (pinkeye)
• Pneumonia
• Lower respiratory infections
• Urinary or genital tract infections
• Polyarthritis

Your veterinarian will need to determine exactly what is causing your cat's illness in the instances mentioned above. One of the possible contributing factors is M. felis. Main causes of these conditions can include common allergies, acholeplasma, ureaplasma, chlamydia, feline herpesvirus (FHV or FHV-1), various fungi, feline calicivirus (FCV), or other viruses.

Once properly identified as a culprit, M. felis can be more effectively treated with antibiotics that target it. A name commonly given to infections caused by all the mycoplasma bacteria is mycoplasmosis. Mycoplasma tends to worsen or prolong infections caused by other agents; this is more often the case than for it to be the primary cause of the infection. It rarely acts alone in causing disease.

What are the Symptoms of Mycoplasma felis?

Symptoms would come from the conditions being caused by the M. felis. Your cat would not likely have all of these symptoms, only the ones specific to the disease in the area of the body infected. They could include:

• Severely swollen eyes
• Eye and/or nasal discharge
• Frequent sneezing
• Lameness
• Difficulty walking or grooming
• Difficulty stepping up into the litter box (may cause litterbox avoidance)
• Fever
• Squinting
• Spasmodic blinking
• Long-term skin abscesses
• Weakened newborns of infected mothers
• Stillbirths or early kitten deaths

Cats afflicted by immune deficiencies such as feline leukemia (FeLV) or feline immunodeficiency (FIV) viruses may be more susceptible to infection from mycoplasma bacteria. Often, a cat presenting the above symptoms may be tested for both of these as a precaution.

How is Mycoplasma felis treated?

Your veterinarian will take a sample of your cat's eye fluid or swab the throat, or may extract a bit of joint fluid, depending on the type of infection. The vet will also check for inflammation. The sample is sent off to a lab, where they will test it for the presence of M. felis. If it is present in the sample, your cat will be given an antibiotic. This test will likely run you a couple hundred dollars, but is the only way of knowing for sure if M. felis is contributing to your cat's illness.

Typical broad-spectrum antibiotics used to combat diseases caused or exacerbated by M. felis as of this writing include:

• amoxicillin with clavulanic acid
• cephalosporins
• trimethoprim-sulfa
• fluoroquinolones
• tetracyclines
• chloramphenicol

The two most effective against M. felis are thought to be the tetracyclines and fluoroquinolones. The specific drugs doxycycline and pradofloxacin were found to be effective against M. felis in a 2008 German study. Doxycycline was slightly more effective at eliminating M. felis completely, although both relieved the cats' symptoms within the first week of treatment. A 2016 study funded by the Winn Feline Foundation reported that minocycline and azithromycin are also quite effective against M. felis.

If your kitty's eyes are affected, your vet may prescribe an antibiotic ophthalmic ointment or drops in addition to the medicine given by mouth. If swelling or pain are being caused by the infection, your vet may give a non-steroid anti-inflammatory (NSAID), which may also be included in the ophthalmic ointment/drops. 

Luckily, most cats have a good prognosis when infected by mycoplasma. Young kittens or geriatric cats may have more difficulty overcoming it. Milder cases can last from five to ten days, while more severe ones may stretch out for up to six weeks. Normally antibiotic treatment will continue for at least three weeks. By the time most people have their cats tested for M. felis, the longer recovery time is typical.

Home treatment of these infections is typical, once properly diagnosed. Your cat should not need hospitalization. You may want to make your kitty more comfortable by dabbing the eye and nose secretions periodically with a tissue. If your cat is reluctant to eat, it could be that the sense of smell is compromised, so try an especially aromatic food. This is the time to spoil your cat with his favorite! Make sure kitty is drinking plenty of fluids, to help thin and clear the nasal and eye secretions.

The length of treatment will be determined by your vet, depending on your cat's condition. You will usually need to be giving antibiotics for a fairly long time. Supplements to boost your cat's immune system may help with recovery, as well as helping your kitty stave off a reinfection.

Is There Any Way to Prevent Mycoplasma felis?

Because these bacteria are everywhere, there is no vaccine to prevent infection. Sunlight and chemical disinfectants kill these bacteria. The best prevention is to keep your cat's environment as clean as possible.

In multi-cat households, if one of your cats tests positive for M. felis, that bacterium will be present in the cat's nasal discharge for the rest of its life. But, as discussed above, it exists virtually everywhere else in nature anyway, so this should not present any more of a danger to your other cats than merely living in the world.

If your cat is suffering from repeated upper respiratory or eye infections, ask your vet about having the test done for Mycoplasma felis. Getting the proper treatment could actually save you money in the long run, and will certainly make your kitty feel better!

Sources: "Bacterial Infection (Mycoplasma, Ureaplasma, Acoleplasma) in Cats", Pet M.D.; "Mycoplasma felis" Zoologix (test description); Ned F. Kuehn, DVM, MS, DACVIM, Section Chief, Internal Medicine, Michigan Veterinary Specialists, "Feline Respiratory Disease Complex" Merck Veterinary Manual; "Mycoplasma felis", The Cat Site; Dr. Marie, "mycoplasma felis respiratory infection", AskAVetAQuestion.com; AD Hartmann, CR Helps, MR Lappin, C Werckenthin, and K Hartmann, "Efficacy of pradofloxacin in cats with feline upper respiratory tract disease due to Chlamydophila felis or Mycoplasma infections", U.S. National Library of Medicine; Susan Little, DVM, DABVP (Feline) and Matthew Kornya, DVM, "Upper Respiratory Infections in Cats", Winn Feline Foundation.

Health Spotlight: Feline Uveitis

Photo: Staci Machado

Health Spotlight: Feline Uveitis

A recent Facebook post to the CatCentric group devoted to healthy cats described the poster's cat's diagnosis as lymphocytic plasmacytic uveitis. The kitty is pictured above. She couldn't find anything on this condition and asked for help, so here's what I discovered upon researching it.

What is Uveitis?

Uveitis is a medical term for inflammation of the middle layer of the eyeball, which is known as the uvea. This portion of the eye contains a large number of blood vessels that nourish your cat's eyes. Uveitis is not a disease in and of itself, but a condition that can be symptomatic of injury or any number of diseases or other conditions.

Some cats who develop uveitis also develop glaucoma due to an imbalance of normal fluids (vitreous humor) inside the eyeball. The fluids are unable to drain as they usually would because of the inflammation, so they build up and create pressure in the eye.

What Causes Feline Uveitis?

Many things can cause the middle layer of the eyeball to become swollen. Several factors can increase a cat's likelihood of developing this condition:

• Bodily infections, commonly of the lungs or central nervous system
• Viruses, such as FHV-1, FeLV, or FIV
• In cats under 2 years of age, feline infectious peritonitis (FIP)
• Parasites, such as Toxoplasma gondii or Bartonella
• Systemic inflammatory diseases, such as inflammatory bowel disease
• Tumors or cancers
• Allergies or immune system deficiencies
• Living with smokers
• Injury to the eye (uncommon cause) or corneal ulcers
• Fungal infection (rare)

In most cases, the uveitis is caused by an infection of some type. The diagnosis given to the cat pictured above, "lymphocytic plasmacytic uveitis," indicated that the veterinarian was unable to identify the cause of the condition. Lymphocytes and plasmacytes are two types of white blood cells that are essential to the body's immune system. When the cause of uveitis is uncertain (idiopathic), lymphocytic plasmacytic uveitis is the diagnosis commonly used to describe it.

Many kittens in wild colonies or overcrowded conditions are exposed to FHV, the feline herpesvirus-1. This is a different type of herpes virus than the one that affects humans, and it is not transferrable between cats and humans. FHV often manifests in the eyes, respiratory and gastrointestinal tracts. Cats affected by FHV tend to sneeze a lot, have runny eyes, conjunctivitis (pink eyelids), and possibly have ulcers on the eyes, among many other symptoms. The uveitis is a secondary condition to the FHV infection. As with the type of herpes virus that infects humans, this one also remains dormant in the cat's system and may flare up again in times of stress.

FIV, the feline immunodeficiency virus, may be an underlying cause of uveitis in cats 5 years or older. These tend to be milder cases of uveitis, and you may not notice it until the secondary glaucoma develops. These cats' eyes may sometimes appear to have a cataract. In many cases, the uveitis will appear several months to years before the cat tests positive for the virus. FIV is controllable (although not curable at this time), and is no longer the fatal diagnosis it used to be; it can be managed and cats can live many happy years with it now.

The feline leukemia virus, FeLV, is a retrovirus that affects only about 2.3% of all cats. One of its effects is to cause a buildup of protein deposits in the middle coating of the eye, which shows up as the discoloration associated with uveitis.

Most kittens are exposed to the feline calicivirus and will show respiratory symptoms. They may develop corneal ulcers as a result. This can cause them to experience some uveitis. While cats of any age may get this virus, it is more common in kittens.

In cats with full-blown FIP, several of the kitty's organs (kidneys, liver, spleen, lungs) and even the central nervous system are affected by the disease. The uveitis is only one component to the infection that is wracking the entire bodies of these poor cats. Although research continues on a cure or vaccine for FIP, it is often still a fatal diagnosis as of this writing.

When caused by Toxoplasma gondii, or toxoplasmosis, the cat may have a pulmonary (lung) or central nervous system infection in addition to the uveitis. In these cats, the uveitis may be ongoing and the cat's immune system may become suppressed.

Older cats may develop uveitis when an underlying cause cannot be determined. This is especially true for cats who have had a problem with uveitis in the past. This may affect one or both eyes, and often leads to glaucoma.

Lens luxation (displacement of the lens) is a condition that is rare, but more common among Siamese cats, especially aging ones. Uveitis may occur secondary to this condition.

Hyphaema is when blood cells accumulate in the front chamber of the eye. It is similar to uveitis, but has its own set of causes and symptoms.

Some cats with uveitis have tested positive for infection from Bartonella, a bacteria that causes what is commonly called "cat-scratch fever" when transmitted to humans. This type of bacteria lives in the lining of the blood vessels and is often spread by contact with flea feces. Cats may not show symptoms of infection from it other than mild fever, swollen glands, and slight muscle aches, so you may be completely unaware that your cat has this when you see symptoms of uveitis.

What are the Symptoms of Uveitis in Cats?

If your cat is experiencing uveitis, you may notice the following symptoms:

• The cat's eye color may change (see photo above) due to fluid accumulation
• The eye may appear red or swollen
• The affected eye may produce a lot of tears
• Kitty may squint or show sensitivity to bright light
• The cat's pupil size and shape may change

Uveitis can be a painful condition. The tearing and squinting are indicative of pain. The cat's eye color may change all over, as in the photo above, or it may appear that a dark cloud is covering a portion of the eye. The discoloration comes from fluid building up in the eye, and is usually darker than the iris's natural color.

When your veterinarian examines the cat's eye internally, there may be several indicators that are not apparent by mere observation. When the vet shines a light into the cat's eye, the beam may scatter due to increased protein and inflammatory cells in the natural fluid within the eyeball (the aqueous humour). There may be nodular lesions or excess small blood vessels on the eye's iris. The blood vessels of the retina may be inflamed. These can only be seen with equipment in a vet's office that you do not likely have at home.

How is Feline Uveitis Treated?

This is not something you can treat by yourself at home. Take your cat to a veterinarian for a proper medical diagnosis and treatment. Rapid treatment of uveitis can save your cat's eyesight. If left untreated, it can result in blindness in the affected eye.

Corticosteroids can reduce inflammation and pain of the condition, and are still the most common treatment for uveitis. These may include prednisolone or dexamethasone. You will need to apply the medicine, usually as an ointment, to your cat's affected eye multiple times per day at first, slowing to only once or twice daily as the condition responds to treatment.

In severe cases, your vet may administer a corticosteroid underneath the surface of the cat's eye. This should only be done in rare instances when the swelling has affected the back portion of the eye, and the condition is not caused by an infection.

If the cat has a fungal infection that has affected the internal organs, kitty's prognosis is not good, although treatment with imidazole therapy has been documented. Luckily, fungal infections in cats are rare.

Depending on the cause, the underlying infection, disease, or condition must be treated to decrease the likelihood that the uveitis will reoccur. This may involve referral to a veterinarian specializing in feline oncology or rheumatology. In cases of FIP or FIV, there is no specific treatment currently available. For Bartonella, azithromycin has been used successfully.

While human uveitis can sometimes be treated by dilating the pupils to reduce inflammation, constriction of the feline pupil is not usually a problem in cats suffering from uveitis, so this is not a treatment used by veterinarians.

Is There Any Way to Prevent Feline Uveitis?

Not all the diseases that can cause uveitis are preventable. Sometimes, cats are exposed to pathogens before we take them in. If you adopt a new kitten or cat, have your veterinarian check out the kitty and give it a clean bill of health prior to introducing it to your other cats.

Cancer can occur in even the healthiest of cats. If the uveitis occurs as a side effect of a type of cancer, only your veterinary oncologist can help with treatment. There is no known prevention for cancer at this time.

Keeping your cat healthy and kitty's environment flea-free is the best defense against many of the diseases that may cause uveitis. Feeding quality food and supplementing with a good probiotic will support your cat's immune system and keep the body strong.

Treat your cat for fleas and vacuum often to keep your home free of fleas and ticks that may bring diseases like bartonellosis.

If you do see any discoloration in your cat's eye(s), seek a veterinarian's opinion first. With such a myriad range of causes, it's important to have proper testing done to see if anything can be done for the underlying condition causing it.

Sources: "Feline uveitis: aqueous flare intensity excellent clinical monitor" by Johnny D. Hoskins, DVM, PhD, DACVIM, Veterinary News dvm 360, September 1, 2005; "What is Uveitis?" by Kierstan Boyd and reviewed by Robert H. Janigian Jr. M.D., American Academy of Ophthalmology, March 1, 2017; "Cat Scratch Fever in Cats", Pet MD; "Anterior uveitis", Vetbook, "Feline Calicivirus Infection in Cats", Pet MD.