What is an Infectious Disease in Cats?

What is an Infectious Disease in Cats?

What is it?

Infectious diseases in cats are caused by microorganisms such as bacteria, viruses, fungi, and parasites. Cats can contract infectious diseases through various routes, including direct contact with infected animals, contaminated food and water, and insect bites. Preventative measures such as vaccination, regular veterinary check-ups, and good hygiene practices can help reduce the risk of infectious diseases in cats.

How is it Treated?

Treating infectious diseases in cats depends on the specific condition and the cat’s overall health. Treatment may involve medications such as antibiotics, antivirals, and antifungals and supportive care to manage symptoms and improve the cat’s comfort. Preventative measures such as vaccination and good hygiene practices can also help reduce the risk of infectious diseases in cats.

Breed Predispositions

 Infectious diseases can affect any cat breed and cats of any age or gender. 


When Emily noticed her once-playful Persian cat, Misty, had become lethargic and lost her appetite, she knew something was amiss. Concerned for her feline friend’s well-being, Emily scheduled a visit to her veterinarian for a comprehensive examination. After conducting several tests, the veterinarian informed Emily that Misty was suffering from an infectious disease, a common yet serious health concern for many cats.

Pet cats are adorable animals. They’re friendly, playful, and loving. However, they can also be carriers of diseases that affect humans. These infectious diseases in cats are illnesses caused by germs that enter the body and cause infection. The standard form of these diseases is easily treated, while others are fatal.

Infectious disease refers to any disease caused by microorganisms such as bacteria, viruses, fungi, protozoa, ringworm infections, or parasites. The term “infection” means invading one organism into another host. An infection may be acute (short-lived) or chronic (long-lasting). Some conditions cause symptoms immediately, while others do not produce symptoms until the later stages of the disease.

There are several types of feline infectious diseases. Here are the common ones:

Feline Leukemia Virus

Feline leukemia virus (FeLV) is a retrovirus that causes cancer in domestic cats. FeLV infects cells of the immune system, causing them to become malignant. The disease progresses slowly over several years, often resulting in death within five years after infection.

FeLV is spread through saliva and urine. The virus is most common among young kittens and adult cats who live together. Cats infected with FeLV usually show no symptoms until the later stages of the disease. 

There are two types of Feline Leukemia Virus (FeLV):

  1. The FeLV-A virus causes leukemia in cats and is usually spread through saliva.
  2. The FeLV-B virus causes lymphoma in cats and is usually transmitted via blood transfusions.

Both viruses cause serious health problems in cats. However, there is no cure for either type of FeLV.


Symptoms include loss of appetite, weight loss, vomiting, diarrhea, fever, weakness, depression, lack of coordination, and difficulty breathing. Cats may develop tumors, enlarged lymph nodes, bleeding disorders, and kidney failure in advanced cases.


Treatments for FeLV include chemotherapy, radiation therapy, surgery, and supportive care; however, the most effective treatment is prevention through vaccination.

Vaccination against FeLV is available at veterinary clinics. Vaccine manufacturers recommend annual booster shots. However, some veterinarians believe that yearly boosters may be optional.

Feline Immunodeficiency Virus (FIV)

Feline immunodeficiency virus (FIV) is a retrovirus that causes feline AIDS. The disease is similar to human-acquired immune deficiency syndrome (AIDS). According to the American Association of Felines Practitioners, approximately 1 million cats live with FIV worldwide. About 10% of these cats develop full-blown FIV infections.

Cats have two types of Feline Immune Deficiency Virus (FIV): Type 1 and Type 2.

  • Type 1 FIV is transmitted through bite wounds and blood transfusions; however, most cases occur when kittens receive vaccines against FeLV at birth. This type of infection usually goes away within a couple of years.
  • Type 2 FIV is spread through saliva and vaginal fluids. Most cats who contract this virus become sick within three months after exposure. Some cats never develop symptoms, but others may experience weight loss, fever, depression, diarrhea, vomiting, and lymph node enlargement.

Although cats cannot contract HIV, they can be infected with FIV. This means that some cats may develop symptoms of AIDS after being exposed to the virus.

Feline Immunodeficiency Virus (FIV)


Although most cats infected with FIV remain healthy, some may eventually become ill. Cats contracting FIV often experience weight loss, fever, diarrhea, vomiting, coughing, depression, lethargy, and sometimes neurological problems. Some cats with FIV die within two years of contracting the virus.


There are two types of treatment options available for FIV:

  • Antiviral drugs

Antiviral drugs work by inhibiting viral replication. They’re usually administered orally, once daily.

  • Interferon therapy

Interferon therapy works by stimulating the immune system to fight off the infection. It’s given intravenously, three times per week.

Because FIV is spread through bites and saliva, keeping your cat away from other anima is essential. Also, FIV is contagious; you should avoid sharing food, water bowls, litter boxes, grooming tools, bedding, toys, and clothing with your cat.

Feline Calicivirus (FCV)

FCV is a contagious disease that causes severe diarrhea in cats. FCV is spread through direct contact with infected feces. The virus may be transmitted via contaminated food or water bowls, bedding, toys, litter boxes, grooming supplies, flea collars, and cat carriers.

FCV is most commonly seen in young kittens, but older cats can be affected too. Although, young kittens are at the highest risk because their immune systems aren’t fully developed. As a result, older cats may not show any signs of disease until after exposure to the virus.

Cats can be carriers of FCV and shed the virus in their feces for several weeks after recovery. Therefore, cats sharing a household with another cat should be tested for FCV at least once every three months.


Most cats infected with FCV show no signs of illness. However, some cats develop mild diarrhea, vomiting, fever, lethargy, and loss of appetite. These symptoms usually last only a day or two. However, some cats may become very ill and die within 24 hours after exposure to FCV.

Symptoms typically appear around two weeks. The most common symptom is diarrhea, followed by vomiting and fever. Other symptoms include depression, weight loss, lack of energy, and dehydration.


Treatment options for your cat who tests positive for FCV include supportive care and medications. Supportive care includes fluids, electrolytes, pain relief, and antibiotics. Medicines that treat FCV include antiviral drugs, such as feline amantadine hydrochloride tablets, and immunosuppressants, such as prednisone.

FCV is treatable with antibiotics. However, some cats who recover from FCV develop long-term health problems, including kidney failure. So be careful when treating your pet.

Your vet may recommend a combination of treatments to help reduce the severity of the disease. Your vet may also suggest vaccinating cats at risk of contracting FCV.

These vaccines are safe and effective. They contain live viruses that stimulate immunity in your cat. This enables the production of antibodies that fight off future infections.

FCV vaccines work best when administered within ten days of exposure to the virus. After that, the vaccine loses its effectiveness. To ensure maximum protection, ask your vet to give two vaccine doses two weeks apart.

Feline Infectious Peritonitis (FIP)

FIP, known as feline distemper, is a fatal disease in cats. This is associated with a viral infection, feline coronavirus infection. The virus causes inflammation of the body’s organs, especially the liver, spleen, lungs, kidneys, intestines, heart, brain, eyes, and skin. FIP is spread through direct contact between infected and healthy cats.

This condition affects older cats and is often fatal. It usually occurs after an infection has been present for a prolonged period.


Some clinical signs include high fevers, depression, loss of appetite, nausea, diarrhea, and abdominal pains. Unfortunately, there is no known way to treat this deadly disease. However, there are several treatments available to help alleviate symptoms.


Treatments available to help reduce the severity of the disease include antibiotics, anti-inflammatory drugs, nutritional supplements, and dietary modifications. It also involves removing affected organs and replacing them with healthy tissue. If left untreated, the cat may die within days.

Contact your veterinarian immediately if you suspect your cat is suffering from FIP. Your vet should perform blood tests to determine whether your cat has FIP. If your cat tests positive for FIP, it must be treated with antiviral medications and supportive care.

Cat Scratch Disease (CSD)

Cat scratch disease (CSD), also known as cat scratch fever, is a bacterial infection spread through direct contact between cats’ claws and human skin. The bacteria usually infect humans who come into close contact with infected cats. This is caused by bacteria called Bartonella henselae. Cats scratch themselves to remove dead skin cells allowing the bacteria to enter the bloodstream.


Although CSD is not contagious, it can be painful and uncomfortable. Clinical signs include fever, headache, rash, swollen lymph nodes, fatigue, muscle aches, and joint pain. Most cases resolve within two weeks after symptoms appear.


Treatment options for Cat Scratch Disease include antibiotics, steroids, and surgery. The most common treatment is antibiotics.

  • Antibiotics work well when the infection is localized. However, antibiotics may not be effective if the disease spreads throughout the body.
  • Steroids are usually used to treat CSD in kittens. Steroid injections are given directly into the affected area. This helps reduce swelling and inflammation.
  • Surgery is rarely needed. Surgery involves removing infected tissue and draining fluid pockets.

Feline Herpesvirus (FHV1)

Feline herpesvirus (FHV) is a virus that causes feline infectious rhinotracheitis, a highly contagious upper respiratory disease that affects cats worldwide. The virus is spread through direct contact between infected animals and through contaminated environments.

FHV is most commonly seen in young kittens, especially those born during warmer months. However, older cats may be susceptible to infection. Infected cats usually recover within two weeks, although some develop chronic conditions that may last several years.

Cats infected with FHV1 shed viruses in their saliva, urine, feces, and nasal discharge. The virus can be transmitted directly with these fluids or indirectly via fomites (objects that carry infectious material).


The first sign of a flu-like virus (FHV1) is usually watery eyes and sneezing. Other symptoms include runniness, coughs, lethargy, nausea, vomiting, diarrhea, and weight loss. These symptoms typically appear after two weeks and may continue for up to one month.


Treatment options include antiviral medications, topical creams, and laser therapy. Antivirals work by inhibiting viral replication, preventing further infection, and reducing symptoms. Topical creams contain antihistamines and steroids that reduce itching and inflammation. Laser therapy uses light energy to destroy infected cells.

Prevention involves keeping cats away from sick cats, washing hands frequently, and cleaning surfaces where cats sleep and play.


Leptospirosis is a bacterial disease found worldwide that affects animals and humans alike. The bacteria live in water and soil and can be transmitted with infected animal urine or feces.

Cats are particularly susceptible to leptospirosis because they often drink contaminated water and lick themselves clean after defecating. They’re also prone to developing kidney problems when exposed to the bacteria.

This bacterial infection is transmitted via contact with contaminated water or soil. Leptospira bacteria infect the kidneys, liver, and spleen.

leptospirosis in cats


Some common clinical signs of leptospirosis are fever, headache, muscle aches, vomiting, diarrhea, and jaundice. However, these symptoms may only appear several days after exposure. This means that early detection is critical.


There are several effective treatments available. Your veterinarian should prescribe antibiotics based on your cat’s symptoms and medical history.

Some veterinarians recommend administering antibiotics intravenously (IV) rather than orally. This approach may reduce the risk of antibiotic resistance developing.

If your cat develops kidney failure, it must receive dialysis treatment. Dialysis removes toxins from the blood and restores fluid balance. Unfortunately, dialysis is expensive and requires frequent hospital visits. To save money, some owners administer IV fluids at home. However, this method isn’t recommended because it needs to remove more toxins.


Giardia is a parasite that infects humans and animals. Cats are especially susceptible to giardiasis because they lack immunity against this external parasite. This parasitic infection is commonly found in kittens and young cats. Giardia attaches itself to the small intestine lining, causing irritation and inflammation.

Cats can become infected by drinking dirty water or eating feces-contaminated foods. They may also be exposed to contaminated water playing in puddles or swimming pools.


Cats infected with Giardia often show symptoms similar to human cases, including diarrhea, weight loss, vomiting, and dehydration. Loose stool is the most common symptom in dogs, although some dogs may not exhibit any signs.


Treatment involves administering a medication called metronidazole (Flagyl). This drug kills Giardia parasites and prevents them from reproducing. Metronidazole should be administered orally at 10mg/dose twice daily for seven days. If left untreated, giardiasis can lead to death.


To prevent giardiasis, keep your cat away from sources of contamination, including areas where animals defecate. Clean litter boxes regularly and change them out frequently. Also, clean your cat’s food dishes daily and wash your hands after handling your pet.

Rabies Virus

Rabies virus is a deadly disease that affects dogs and cats. This virus is highly contagious and can be passed between cats and dogs. The rabies virus attacks the brain, causing paralysis, convulsions, and death. Rabid animals bite humans, often resulting in painful wounds. Rabies is fatal once symptoms appear.

There are two types of rabies virus: wild and vaccine strains. The rough version causes rabies in dogs and humans, whereas the immunization stress only affects animals.

Rabid animals transmit the disease by biting people. This often occurs between domesticated dogs and wild carnivores, such as foxes. However, any mammal, including bats, skunks, raccoons, coyotes, wolves, jackals, ferrets, badgers, weasels, civets, and others, can be infected.


Symptoms in cats include loss of appetite, lethargy, vomiting, diarrhea, fever, seizures, paralysis, coma, and death. Symptoms vary depending on the cat’s age and health status when infected.

Cats usually become sick between two weeks and six months after being bitten by an infected animal. The incubation period (time between infection and onset of symptoms) ranges from three days to four months. As a result, cats may be carriers of the rabies virus for several years following recovery from the disease.


Although there is no cure for rabies, vaccination is available. Vaccination is safe and effective, and there’s no risk of side effects. However, it takes at least two vaccine doses to protect against this disease fully. Vaccination also doesn’t protect pets from contracting rabies from other animals.

Your cat must receive postexposure prophylaxis (PEP) if it tests for rabies. PEP consists of five doses of rabies vaccine administered at intervals of no longer than 28 days. After receiving PEP, your cat should be monitored closely for signs of illness.

If your cat shows no signs of illness within 30 days, it can be released from quarantine. However, if your cat shows clinical signs of disease, it must remain quarantined until fully recovered.

Your cat cannot transmit rabies to another animal. However, if your pet bites another animal, the second animal may develop rabies. This is known as a “zoonotic” transmission.

To prevent zoonotic transmissions, keep your pets away from wild animals. Also, avoid letting your dog roam outdoors because dogs can easily pick up stray animals.

How to Prevent Your Cat From Getting Infectious Diseases?

Preventing common cat diseases is essential because many cat owners are concerned about their pets getting sick. But there are ways to avoid illness.

  1. Be aware of common feline illnesses and symptoms. This includes recognizing when your pet needs veterinary care.
  2. Keep your cat healthy by feeding her a well-balanced diet and providing plenty of fresh water.
  3. Vaccinate your cat against rabies and distemper. These vaccines protect against life-threatening infections in cats, but vaccines are available but not 100% preventative.
  4. Wash your hands frequently after handling your cat. First, wash them thoroughly with soap and warm water. Then dry them off with paper towels.
  5. Clean your cat’s litter box regularly. Make sure it’s not too smelly or dirty. And remember to change the litter at least once every three months.
  6. Avoid giving your cat fleas. Keep your cat indoors. Flea infestations can be acquired if your cat keeps on going out. These can cause skin irritation and hair loss. They can also spread disease. So take steps to stop fleas from spreading.

Frequently Asked Questions

Cats have been known to suffer from many diseases but tend to recover well if given proper treatment. However, there are some conditions where recovery may not be possible and often develops secondary infections. You have to make sure your cat has enough nutrients and vitamins. If they don’t get enough food, they won’t be able to fight off any infections.

Humans can get sick from cat feces. The bacteria in cat feces can cause diarrhea, vomiting, nausea, fever, skin rashes, eye infections, ear infections, pneumonia, meningitis, urinary tract infections, and even death.

Cat owners should wash their hands after handling litter boxes, clean up pet waste, and protect children from animal feces.

Humans can get upper respiratory infections (URI) from cats. However, cats can also get URI from humans. Cats’ most common cause of URI is feline herpesvirus 1 (FHV1). FHV1 causes cold sores around the mouth and nose. It is spread through direct contact with infected saliva or urine. The virus may also be transmitted via contaminated bedding or food.

Bacterial infections occur when germs enter the body through the mouth, nose, or ears. Some bacteria can live on surfaces like countertops, furniture, and toys. Others can survive inside the body for several days. Germs can also enter the body through scratches, cuts, burns, insect bites, or other injuries.

Many diseases can be transmitted through cats. Some common ones include Feline Leukemia, Calici Virus, FeLV/FIV, Chlamydia, and Rabies.

Shelters are typically most crowded when families bring new cats in the spring and summer. Feline distemper is sheltering most common cat disease, followed by upper respiratory infection (URI).

Cats get sick from many diseases, but the most contagious disease is probably Feline Calicivirus (FCV).

Disclaimer: The information provided on this veterinary website is intended for general educational purposes only and should not be considered as a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a licensed veterinarian for any concerns or questions regarding the health and well-being of your pet. This website does not claim to cover every possible situation or provide exhaustive knowledge on the subjects presented. The owners and contributors of this website are not responsible for any harm or loss that may result from the use or misuse of the information provided herein.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *