As a cat parent, it is important to recognize the signs and symptoms of common illnesses so you can seek veterinary help for your feline friend in a timely manner if necessary. Read on for information about diseases and other medical inflictions that frequently impact cats.

Upper Respiratory Infections

A cat’s upper respiratory tract—the nose, throat and sinus area—is susceptible to infections caused by a variety of viruses and bacteria.

Causes of Upper Respiratory Infections

  • Viruses are the most common causes of upper respiratory infections (URIs) in cats.
  • Feline calicivirus and feline herpesvirus account for 80 to 90% of all contagious upper respiratory problems, and are prevalent in shelters, catteries and multi-cat households.
  • These viruses can be transmitted from cat to cat through sneezing, coughing, or while grooming or sharing food and water bowls.
  • Once infected, cats can become carriers for life, and though they may not show clinical signs, they can still transmit the viruses to others.
  • Cats often develop bacterial infections secondary to these common viral infections.
  • There are also upper respiratory infections in cats that are primarily caused by bacteria. Chlamydia and Bordetella—commonly found in shelters and areas with multiple cats—are two such bacterial infections.
  • Less common in cats than dogs, Bordetella is usually associated with stress and overcrowded living conditions.

Preventing Upper Respiratory Infections

  • Keep your cat indoors to minimize the risk of exposure to infected animals.
  • Properly isolate infected cats to protect other pets living in the same environment.
  • Minimize stress.
  • Keep your cat up to date on vaccines as recommended by your vet. Vaccines for upper respiratory disease in cats may not actually prevent infection, but they help lessen the severity of the disease in some cases.
  • Regular veterinary exams and preventative care can help catch and treat problems early. A cat’s best defense against upper respiratory infection is a healthy immune system.
  • Practice good hygiene and wash your hands thoroughly when handling multiple cats.

Symptoms of Upper Respiratory Infections

Symptoms differ depending on the cause and location of the infection, but some common clinical signs of upper respiratory problems in cats include:

  • Sneezing
  • Congestion
  • Runny nose
  • Cough
  • Clear to colored nasal discharge
  • Gagging, drooling
  • Fever
  • Loss of or decreased appetite
  • Rapid breathing
  • Nasal and oral ulcers
  • Squinting or rubbing eyes
  • Open-mouth breathing
  • Depression

Diagnosing Upper Respiratory Infections

  • Age, vaccination status and physical condition all play a role in a cat’s susceptibility to upper respiratory infections.
  • Cats who live in multi-cat households or shelters are most susceptible.
  • Veterinarians have found that stress plays a role in causing outbreaks of URI, and cats in any shelter, cattery or boarding facility are generally experiencing high levels of stress.
  • Cats who have recovered from URI can become carriers, and may experience recurrences when stressed.
  • Certain breeds like Persians and other flat-faced breeds have a predisposition to develop upper respiratory infections due to their facial structure.

It’s important to bring your cat to a veterinarian if you think she may be suffering from an upper respiratory infection. A brief exam by a veterinarian will help to determine if your cat requires medication, has a fever or is dehydrated. Avoid self-diagnosis, since your cat may be infectious and require isolation, antibiotics or additional veterinary care.

Treating Upper Respiratory Infections

Your veterinarian will prescribe the best course of treatment for your cat, which may include:

  • Medications
  • Isolation
  • Rest
  • Support with fluids
  • Nutritional support

Left untreated, some upper respiratory infections can progress to pneumonia or have other serious complications, such as blindness or chronic breathing difficulties.


Cats can acquire a variety of intestinal parasites, including some that are commonly referred to as “worms.” Infestations of intestinal worms can cause a variety of symptoms. Sometimes cats demonstrate few to no outward signs of infection, and the infestation can go undetected despite being a potentially serious health problem. Some feline parasitic worms are hazards for human health as well.

Common Types of Worms in Cats

Outdoor cats and those who are routinely exposed to soil where other animals defecate are prone to worms. Kittens and cats who do not receive regular preventative health care are most at risk for developing complications associated with internal parasites.

  • Roundworms are the most common internal parasites in cats. Resembling spaghetti, adult worms are three to four inches long. There are several ways cats can become infected. Nursing kittens can get roundworms from an infected mother’s milk, while adult cats can acquire them by ingesting eggs from the feces of an infected cat.
  • Hookworms are much smaller than roundworms—less than an inch long—and reside primarily in the small intestine. Because they feed on an animal’s blood, hookworms can cause life-threatening anemia, especially in kittens. Hookworm eggs are passed in the stool and hatch into larvae, and a cat can become infected either through ingestion or skin contact.
  • Tapeworms are long, flat, segmented parasites that range from 4 to 28 inches in length. An infestation can cause vomiting or weight loss. Cats acquire tapeworms by ingesting an intermediate host, like an infected flea or rodent. When cats are infected, tapeworm segments—actual pieces of the worm that resemble grains of rice—can often be seen on the fur around a cat’s hind end.
  • Lungworms reside in the lungs of a cat. Most cats will not show any signs of having lungworms, but some can develop a cough. Snails and slugs are popular intermediate hosts of this type of parasite, but cats are usually infected after eating a bird or rodent who has ingested an intermediate host.
  • Though means of transmission can vary, one of the main ways that cats get worms is through the ingestion of the feces of infected felines. Mother cats can also pass on worms to their kittens.

Worm Prevention

  • Keep your cat indoors to avoid exposure to infected cats, rodents, fleas and feces.
  • Make sure your home, yard and pets are flea-free.
  • Practice good hygiene and wear gloves when changing cat litter or handling feces. It’s also important to frequently dispose of stool.
  • Ask your veterinarian to recommend an appropriate internal parasite treatment or prevention program for your cat.

Symptoms of Worms in Cats

Symptoms differ depending on the type of parasite and the location of infection, but some common clinical signs include:

  • Diarrhea
  • Worms visible in stool or segments of worm seen near anus
  • Bloody stool
  • Bloating or round, potbellied appearance to abdomen
  • Weight loss
  • Vomiting
  • Constipation
  • Anemia
  • Coughing
  • Trouble breathing

If you think your cat may have worms, it’s important to bring her to a veterinarian, who can confirm the presence of worms. Avoid self-diagnosis, since worms are not always visible or identifiable.

Treatment for Worms

Please don’t attempt to treat your pet yourself—your cat should be treated for the specific type of worms he has.

  • Not all dewormers eradicate all types of worms.  Your veterinarian will determine the type of worm(s) infestation(s) your cat has, and prescribe the best course of treatment.  Your veterinarian will also be able to tell you if the dewormer should be repeated, and when.
  • Not all dog medications are safe for cats.
  • Some over-the-counter deworming medications can be harmful if used inappropriately.

Transmission of Worms from Cats to Humans

A large number of roundworm eggs can accumulate where cats defecate. People, especially children, who ingest such eggs can develop serious health problems, such as blindness, encephalitis and other organ damage. Treatment of blindness caused by roundworm may involve surgical removal.

Hookworm larvae can penetrate human skin and cause lesions. People can acquire tapeworms through the ingestion of an infected flea, although this is rare.


Rabies is a viral disease that affects the brain and spinal cord of all mammals, including cats, dogs and humans. This preventable disease has been reported in every state except Hawaii. There’s good reason that the very word “rabies” evokes fear in people—once symptoms appear, rabies is close to 100% fatal.

Rabies Transmission

There are several reported routes of transmission of the rabies virus.

  • Rabies is most often transmitted through a bite from an infected animal.
  • Less frequently, it can be passed on when the saliva of an infected animal enters another animal’s body through mucous membranes or an open, fresh wound.
  • The risk for contracting rabies runs highest if your cat is exposed to wild animals. Outbreaks can occur in populations of wild animals (most often raccoons, bats, skunks and foxes in this country) or in areas where there are significant numbers of unvaccinated, free-roaming dogs and cats.
  • In the United States, rabies is reported in cats more than in any other domestic species.
  • Unvaccinated cats who are allowed to roam outdoors are at the highest risk for rabies infection.
  • Feral cat populations remain a reservoir host for the rabies virus.

Rabies Prevention

  • Vaccination is the key—and in many areas of the country, such as New York City, it’s the law.
  • Some local ordinances require lengthy quarantines—or euthanasia—of pets who have bitten someone if their owners do not have proof of current vaccination.
  • Vaccinating your cat doesn’t just protect her from rabies—it also protects your cat if she bites someone.
  • In municipalities where rabies vaccinations for cats are not required, the decision to vaccinate is best left to the judgment of the veterinarian and the cat guardian because some cats experience serious side effects to the rabies vaccine.
  • The vaccine should definitely be administered if your cat spends any time outdoors (ASPCA experts recommend keeping pet cats indoors).

Symptoms of Rabies

  • Animals will not show signs immediately following exposure to a rabid animal. Symptoms can be varied and can take months to develop. Classic signs of rabies in cats include:
  • Changes in behavior (including aggression, restlessness and lethargy),
  • Increased vocalization
  • Loss of appetite
  • Weakness
  • Disorientation
  • Paralysis
  • Seizures
  • Sudden death

Diagnosing Rabies

  • There is no accurate test to diagnose rabies in live animals.
  • The direct fluorescent antibody test is the most accurate test for diagnosis, but it can only be performed after the death of the animal.
  • The rabies virus can incubate in a cat’s body anywhere from just one week to more than a year before the virus appears in the saliva and the cat is capable of transmitting the disease.
  • When the animal becomes infectious, symptoms appear quickly.  It is possible for a cat, or dog, to shed the virus for several days before clinical signs appear.
  • There is no treatment or cure for rabies once symptoms appear. The disease results in fatality.

What to Do if Your Cat Interacts With a Rabid Animal

  • Put gloves on to protect yourself from infection.
  • Call your veterinarian for an immediate appointment!
  • Contact local animal control officers if the animal who bit your pet is still at large; they will be best able to safely apprehend and remove the animal from the environment.
  • A cat who is up to date with his vaccinations and who has been bitten by a possibly rabid animal should also be given a rabies booster vaccine immediately and kept under observation for 45 days.
  • If you think you’ve been bitten by a rabid animal, see your doctor immediately!

Note: Do not attempt to handle or capture a wild animal who is acting strangely (i.e., a nocturnal animal who is out during the day, an animal who acts unusually tame). Report the animal to local animal control officers as soon as possible.

High-Rise Syndrome

Many pet parents eagerly open their windows to enjoy the weather during the summer months. Unfortunately, unscreened windows pose a real danger to cats, who fall out of them so often that the veterinary profession has a name for the complaint—High-Rise Syndrome. Falls can result in shattered jaws, punctured lungs, broken limbs and pelvises—and even death.

  • Cats have excellent survival instincts, and they don’t deliberately “jump” from high places that would be dangerous. Most cats fall accidentally from high-rise windows, terraces or fire escapes.
  • Cats have an incredible ability to focus their attention on whatever interests them. A bird or other animal attraction can be distracting enough to cause them to lose their balance and fall.
  • Because cats have little fear of heights and enjoy perching in high places, pet owners often assume that they can take care of themselves. Although cats can cling to the bark of trees with their claws, other surfaces are much more difficult, such as window ledges, concrete or brick surfaces.
  • When cats fall from high places, they don’t land squarely on their feet. Instead, they land with their feet slightly splayed apart, which can cause severe head and pelvis injuries.
  • It is a misconception that cats won’t be injured if they fall from one- or two-story buildings. They may actually be at greater risk for injury when falling shorter distances than by falling from mid-range or higher altitudes. Shorter distances do not give them enough time to adjust their body posture to fall correctly.
  • When cats fall from high-rise buildings, they may end up on sidewalks or streets that are dangerous and unfamiliar to them. Never assume that the animal has not survived the fall; immediately rush the animal to the nearest animal hospital or to your veterinarian.
  • There is a 90% survival rate for cats who are high-rise victims if they receive immediate and proper medical attention.

Preventing High-Rise Syndrome

To keep your cat safe during the summer, take the following precautions:

  • Install snug and sturdy screens in all your windows.
  • If you have adjustable screens, please make sure that they are tightly wedged into window frames.
  • Note that cats can slip through childproof window guards—these don’t provide adequate protection!

Cat Bite Wounds

Fight wounds are common in cats because they are territorial by nature. Fighting is a behavioral response to defending their territory.

Male cats typically fight more often and sustain more cat bite injuries than females. Most untreated cat bite traumas result in infection, so treatment is necessary to prevent serious illness and disease.

Localized infections, such as an abscess or a closed-off pocket of puss, are common bite wound complications. More serious developments such as cellulitis and systemic illness resulting in infection and even sepsis may result if bite wounds are left untreated.

Common Clinical Signs/Symptoms

  • Swelling under the skin that can be warm to the touch and usually painful
  • Limping
  • Lethargy
  • Fever
  • Excessive grooming of the affected area

In more severe cases:

  • Lethargy and fever
  • Cellulitis—a bacterial infection of the tissue beneath the skin
  • In very rare circumstances, septic arthritis, osteomyelitis or an infection of the joint or bone can occur

Common Treatments for Cat Bite Wounds

Your veterinarian will check your cat’s entire body, clean wounds properly with antiseptic and recommend systemic antibiotics. If your veterinarian treats the wounds with antibiotics within 24 hours, you most likely prevent a localized infection or abscess infection.

If your cat does not receive antibiotics immediately, an abscess likely will form resulting in more involved treatment. With an abscess, your veterinarian will recommend opening, draining and cleaning the site with antiseptic flush.

More extensive wounds may requiring a debridement—removal of the unhealthy tissues—and placement of a drain for a few days. Your veterinarian is the best resource for creating an appropriate treatment plan with you for your cat.

Prevention is essential to avoid cat bite traumas. Neutering your cat may reduce the territorial behavioral that leads to cat fights. Keeping your cat indoors during the evening when cat fights are more common also can help prevent trauma.

Feline Leukemia (FeLV) and Feline Immunodeficiency Virus (FIV)

Feline Leukemia or FeLV in cats is a highly contagious retrovirus and possibly fatal. The disease suppresses a cat’s immune system, potentially setting him up for illness and secondary infection.

This virus is transmitted through shared contact, such as a cat food bowl or a water bowl.

Feline leukemia is diagnosed with a simple blood test. Most veterinarians test yearly for FeLV in cats as part of a routine screening examination based on the cat’s lifestyle and risk of disease.

Feline Immunodeficiency Virus or FIV is a highly contagious retrovirus that suppresses and weakens a cat’s immune system, thus reducing his ability to fight infection. Cat fights commonly spread FIV through the saliva in bite wounds and scratches.

Common Clinical Signs/Symptoms of FeLV and FIV

  • No signs at all, as some cats are positive for either retrovirus and never exhibit any signs of illness
  • Runny eyes or nose
  • Weight loss
  • Bad breath
  • Periodontal disease (oral disease)
  • Loss of appetite
  • Vomiting
  • Lethargy
  • Pale gums

Preventive Measures

Unfortunately, FeLV and FIV cannot be treated; they are lifelong diseases. The good news is that they are not automatically fatal. All cats are at risk for infection, so prevention is key.

  • Yearly vaccinations, especially if your cat goes outside or is exposed to other cats
  • Yearly wellness visits and screening blood tests to assess for exposure to disease
  • Limiting exposure to other cats. If possible, keep your cats indoors to decrease his risk of exposure to other felines.
  • Spay or neuter your pet. This help to decrease the behavior desire to mate or fight with other cats.
  • Make sure any new cats to the household are disease-free prior to coming home.