Common Cat Diseases: Symptoms Every Cat Owner Should Know
Changes in appetite, weight, energy, breathing, skin, or litter-box habits can be the first clues that a cat is ill. Cats often hide discomfort, so small shifts in routine may matter. What can those changes tell you before your cat seems seriously sick?
Lethargy means unusually low energy or reduced interest in normal activities. One sign can have many causes, so a veterinarian must assess symptoms instead of relying on a home diagnosis. This article helps you spot changes and know when to seek advice. A change from your cat’s usual pattern matters more than a comparison with another cat.
Key Takeaways
- Compare your cat’s habits with its own normal routine.
- Changes in appetite, weight, or energy may signal illness.
- Breathing, skin, and litter-box changes also deserve attention.
- One symptom alone cannot tell you which disease is present.
- Ask a veterinarian to assess persistent or concerning changes.
Cat Diseases Symptoms: Early Clues to Watch For
A cat that suddenly hides, stops playing, or leaves food behind may be showing an early health change. Small shifts can be easier to spot than illness itself, since cats often mask discomfort. Look for changes from your cat’s own routine, not a single symptom in isolation.
A symptom-photo guide can help you notice visible details, such as crust around the eyes, a patchy coat, or a swollen area. Pictures cannot identify the cause. Similar signs may come from different health problems, so appearance alone cannot diagnose a cat.
Changes in appetite, weight, and energy
Check whether your cat finishes meals, gains or loses weight, or spends more time alone. Chronic kidney disease (CKD) is common in senior cats but can affect cats of any age. Increased thirst, increased urination, and weight loss are often noticed first.
Hiding or less play may reflect discomfort, stress, or illness. Bad breath, drooling, or reluctance to eat can point to oral trouble. Up to 90% of cats over age 4 have some form of dental disease.
- Appetite or weight shifts.
- Hiding or reduced play.
- Coat or grooming changes.
- Eye or nose discharge.
- Changes in drinking or urination.
- Stool changes or vomiting.
Keep track of changes that persist or appear together, rather than trying to name a disease from one clue.
Grooming, breathing, and litter-box changes
A greasy or untidy coat may mean your cat is grooming less. Redness, scabs, hair loss, or a new lump can show up in pictures, but a veterinarian must assess what caused them. Eye or nose discharge may also be clear, cloudy, or crusted.
One symptom can have several causes, and a cat’s age or usual habits can change what seems normal. Check food, water, and litter-box habits regularly so you know what is normal for your cat.
Which Viruses Can Affect Cats and Kittens?
Feline panleukopenia virus (FPV) can cause severe illness or death, especially in kittens under 5 months old. Rapid care matters for young or unvaccinated cats with signs of illness. Other fast-moving conditions also need prompt veterinary attention.
Visible signs in pictures may include vomiting, eye discharge, or a swollen belly. Appearance alone cannot identify a virus. FPV can cause severe illness and death, particularly in young kittens, so a sick kitten needs quick assessment.
FPV can become severe in kittens
FPV is highly contagious and can survive in the environment for up to a year. It spreads mainly through infected feces and contaminated surfaces, food, water, bedding, bowls, or litter boxes.
Early signs include lethargy, appetite loss, fever, vomiting, and diarrhea. Advanced illness can cause dehydration, weakness, collapse, or sudden death. A veterinarian may test feces, vomit, or anal swabs with a snap test or PCR. A negative fecal snap test may need confirmation.
FPV has no cure. Supportive care may include IV fluids, nutrition, antibiotics for secondary infections, and medicine for vomiting and pain. Shelter kittens start vaccination at 4 weeks, then get boosters every 2 weeks until 16-20 weeks.
FeLV and FIV affect the immune system
Feline leukemia virus (FeLV) affects 2%-3% of cats in the United States and Canada, and up to 30% of ill or high-risk cats. It can spread through close contact, bites, grooming, shared dishes or litter boxes, and from mother to kitten before birth or during nursing.
Screening often begins with an ELISA blood test. A positive FeLV screen needs follow-up testing. After recent exposure, retest in 3-6 weeks. Most positive tests need another check in 6-12 weeks to assess progressive or regressive infection. FeLV has no definitive cure.
Feline immunodeficiency virus (FIV) may take months or years to cause signs. It spreads mainly through deep bite wounds, not casual contact. Mother-to-kitten spread is less common. Maternal antibodies can affect test results in kittens younger than 6 months.
FIP can have wet or dry signs
Feline infectious peritonitis (FIP) develops from feline coronavirus, but most feline coronavirus strains do not lead to FIP. Cats may inhale or ingest virus from an infected cat or contaminated surface. The virus can survive for weeks.
About 1%-5% of exposed cats develop lethal FIP. Cats under 2 or 10 and older have increased susceptibility. Wet FIP can cause fluid in the abdomen or chest and trouble breathing. Dry FIP may involve weight loss, depression, anemia, fever, or organ, neurologic, or eye signs.
Antibody tests show exposure to feline coronavirus but do not confirm FIP. A veterinarian must weigh the signs and other test results to assess the disease.
Respiratory viruses and H5N1 concerns
Feline herpesvirus and feline calicivirus can cause an upper respiratory infection (URI). Cats can spread these viruses through grooming, shared bowls, coughing, or sneezing.
Veterinarians should consider H5N1 in cats with sudden respiratory or neurologic illness. Do not feed cats raw milk or other raw animal products.
| Virus | Main route of spread | A useful clue | Testing or prevention detail |
|---|---|---|---|
| FPV | Feces and contaminated bowls or litter | Fever, vomiting, diarrhea | Vaccination; fecal snap test or PCR |
| FeLV | Close contact, bites, shared dishes | Positive screening blood test | Confirm positive ELISA results |
| FIV | Deep bite wounds | Signs may take years to appear | Maternal antibodies affect tests under 6 months |
| FIP | Inhaling or ingesting feline coronavirus | Fluid in chest or belly, or dry-form signs | Antibody tests show exposure, not FIP |
Keep vaccination decisions tied to a veterinarian’s assessment of the cat’s age and exposure risk.
When Do Vomiting and Diarrhea Need Veterinary Care?
A brief digestive upset may pass, but diarrhea lasting longer than a day or two with poor appetite, lethargy, or vomiting needs veterinary care. Persistent symptoms may have causes beyond a recent food change. Seek veterinary care as soon as possible when diarrhea lasts longer than a day or two alongside those signs.
A cat with disease symptoms and diarrhea may need an exam even when its food has not changed. Parasites, infection, and other health problems can affect digestion. A veterinarian can assess the cat and decide whether testing or treatment is needed.
Diarrhea and signs that raise concern
A single soft stool in an otherwise well cat differs from diarrhea that keeps going or gets worse. Watch whether your cat is eating, drinking, and acting as usual. Poor appetite, low energy, or vomiting along with diarrhea raises the concern.
Call a veterinary clinic for advice when symptoms persist, worsen, or occur together. Diarrhea lasting over a day or two with poor appetite, lethargy, or vomiting needs care as soon as possible.
Vomiting and upset stomach at home
For a mild, brief upset, keep fresh water available and ask a veterinarian what to do next. Do not give human medicine or an unverified home remedy. Some over-the-counter medicines can harm cats with diarrhea.
Note when vomiting started and how often it happens before you call. A short episode may not need the same response as repeated vomiting or worsening diarrhea. Keep your cat’s water available while you arrange veterinary advice, and do not give an over-the-counter medicine without veterinary direction.
What Do Diabetes and Cancer Look Like in Cats?
A cat that drinks and urinates more while losing weight may have diabetes, while a new lump or persistent sore needs veterinary assessment. These clues need context, since other illnesses can cause similar changes. A lump is a finding, not a cancer diagnosis.
Diabetes changes thirst, urination, and weight
Diabetes can change a cat’s appetite, thirst, urination, weight, and energy. Some cats eat more, while others eat less. Weight loss, unusually sweet-smelling breath, dehydration, or an unkempt coat can also occur.
A cat may urinate more or outside the litter box. Diabetes can also occur with a urinary tract infection. A veterinarian uses clinical signs, a physical exam, blood work, and urinalysis to diagnose the disease.
Most cats with diabetes need insulin injections at the same time each day, coordinated with regular meals. Steady timing helps you follow the treatment plan. A veterinarian will set the plan for your cat.
Cancer signs and veterinary assessment
Cancer may cause lumps, swelling, persistent sores, skin infections, abnormal discharge, or bad breath. Other signs can include lethargy, weight loss, sudden lameness, vomiting, diarrhea, red or scaly skin patches, and appetite loss.
A cat may also have trouble breathing, urinating, or defecating. About 1 in 5 cats may develop cancer during their lifetime. Lymphoma accounts for an estimated 30% of reported feline cancers, and about 85% of feline mammary tumors are malignant.
A veterinarian may assess a lump with a needle biopsy or remove it for a pathologist to examine. Radiographs, ultrasound, and blood tests can help find cancer or check whether it has spread. FeLV is linked to most forms of feline lymphoma except the gastrointestinal form.
White or light-colored cats face a higher risk of squamous cell carcinoma on the ears, eyelids, or nose after repeated sun exposure. Spaying before a cat’s first heat can prevent breast cancer. Keeping cats indoors can reduce exposure to some sun-related skin cancers.
Ask a veterinarian to examine a new lump rather than judging it by touch or appearance.
What Urinary Changes Signal an Emergency?
A cat repeatedly straining in the litter box and producing little or no urine may have a blockage that needs urgent care. Do not wait to see whether repeated attempts pass. A urethral obstruction is especially common in male cats and requires urgent veterinary care.
Feline lower urinary tract disease (FLUTD) is an umbrella term for conditions affecting the bladder or urethra. Straining does not identify one cause. Several problems can create similar urinary signs, so a veterinary exam may be needed.
Watch for frequent litter-box trips, passing only small amounts, blood in the urine, vocalizing, or urinating outside the box. Repeated attempts with little or no urine, especially in a male cat, call for urgent care rather than watchful waiting.
Keep your description factual: note how often your cat visits the box and whether you see urine. Note changes in urine volume and frequency so you can describe them accurately to the veterinary team.
Can Cat Diseases Spread to People?
People can catch ringworm, cat-scratch disease, and roundworm-related illness through different kinds of exposure to cats. The route matters, since each infection reaches people in a different way. FIV infects cats but cannot pass from cats to people.
Ringworm can persist on household surfaces
Ringworm is a fungal skin disease that people can catch from cats. Direct contact with an infected cat’s fur can spread it. Fungal spores can also remain on carpet and furniture, even after the cat has moved away.
Cat-scratch disease follows bites and scratches
Bartonella henselae causes cat-scratch disease. People can get it from cat bites, scratches, or licks. Young cats and kittens are the most likely sources of human infection.
A small skin lesion may appear 1-2 weeks before nearby lymph nodes become swollen and tender. Most cases resolve without antibiotics. A bite or scratch can leave a wound that needs care, especially if it becomes painful or swollen.
Roundworms can cause serious human illness
Toxocara roundworms from cats and dogs can cause serious illness in people, including blindness. People may be exposed to parasite eggs in contaminated soil or other material. Children can face added risk when they put dirty hands in their mouths.
Ringworm is a skin infection people can catch from cats, while scratches can transmit Bartonella henselae. The infections differ in both cause and exposure route.
| Infection or parasite | How people are exposed | Main human concern |
|---|---|---|
| Ringworm | Contact with infected fur or spores on furniture | Fungal skin disease |
| Cat-scratch disease | Bites, scratches, or licks | Skin lesion and tender swollen lymph nodes |
| Toxocara roundworms | Contact with parasite eggs from cats or dogs | Serious illness, including blindness |
Wash cat bites and scratches promptly with soap and water.
What Happens During a Veterinary Exam?
A clear timeline of what changed, and when, gives the veterinarian a useful starting point. Specific details can help narrow down possible causes. Symptoms overlap, so a home diagnosis cannot reliably name the disease.
Before the visit, write down five details that can help explain your cat’s health changes:
- When the change began.
- Changes in appetite or water intake.
- Litter-box changes.
- Current medicines or supplements.
- Possible contact with sick cats or raw animal products.
A veterinary assessment commonly starts with your cat’s history and a physical examination. The vet may ask when signs began and whether they have changed over time.
Tests depend on the signs. The veterinarian may choose a CBC, chemistry panel, urinalysis, fecal testing, or radiographs. Each can help assess a different part of your cat’s health.
Bring a current list of medicines and supplements, including products bought without a prescription.
Which Sudden Signs Need Emergency Care?
Trouble breathing, a seizure, or sudden collapse is a reason to contact an emergency veterinary hospital now. These signs cannot wait for a routine appointment. Severe breathing distress, collapse, and seizures need immediate emergency care.
Other sudden changes can also call for emergency help. Use this five-sign list to decide when to contact an emergency hospital:
- Severe breathing difficulty or open-mouth breathing.
- Seizures.
- Collapse or unresponsiveness.
- Severe, uncontrolled bleeding.
- Sudden inability to walk.
If your cat’s breathing or consciousness is impaired, call an emergency veterinary hospital immediately.
Open-mouth breathing in a cat is an emergency sign. A cat that cannot respond normally or suddenly loses the ability to walk also needs urgent assessment.
Sudden decline can have many causes, including illness or injury. A rapidly worsening cat should not be left to see whether the problem passes.
Mild, short-lived changes may still deserve a call to your veterinarian, but they differ from severe signs that need immediate care. Tell the hospital what changed and when it began.
Conclusion
Noticing a change early is more useful than trying to name the illness at home. Compare your cat’s behavior and routines with its own baseline, then let a veterinarian interpret changes that persist or seem severe.
You do not need to solve the mystery before asking for help. A short note about a new habit can make your call clearer and help the clinic guide you. Write down the change you have noticed and contact your veterinarian for guidance.
