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What is the first symptom of feline leukemia?

The first symptom of feline leukemia is often a persistent loss of appetite accompanied by unexplained weight loss.

Understanding the First Signs of Feline Leukemia (FeLV)

Feline leukemia virus (FeLV) is one of the most common and serious infectious diseases affecting cats globally. While many pet owners are aware of the severity of FeLV, recognizing its early symptoms can be a challenge. Detecting the disease in its initial stages is essential for effective management and improving the quality of life of an infected cat.

What Is Feline Leukemia Virus (FeLV)?

FeLV is a retrovirus that weakens a cat’s immune system, disrupts blood cell production, and significantly increases the risk of various secondary infections and cancers, especially lymphoma and leukemia. Although not transmissible to humans or dogs, it is highly contagious among cats through close contact, sharing of bowls, grooming, and bite wounds.

How Is FeLV Transmitted?

The virus is most commonly spread through:
  • Saliva during mutual grooming
  • Shared food/water dishes
  • Litter boxes
  • Bite wounds
  • From mother to kitten through placenta or nursing
FeLV does not survive long in the environment and is neutralized by common disinfectants, so direct contact is the major mode of transmission.

Who Is Most at Risk?

Cats most susceptible to FeLV are:
  • Kittens with immature immune systems
  • Outdoor cats exposed to feral or unknown-status felines
  • Cats in multi-cat households or shelters
  • Cats born to FeLV-positive mothers

First and Early Symptoms of FeLV

One of the earliest indicators of feline leukemia is a persistent loss of appetite accompanied by unexplained weight loss. These nonspecific signs are often overlooked but can be early red flags of a compromised immune system. Additional early symptoms may include:
  • Poor coat condition
  • Mild fever
  • Lethargy
  • Swollen lymph nodes
Since these symptoms can overlap with less serious conditions, it is essential to consult a veterinarian for proper testing.

Progression and Other Clinical Signs of FeLV

As the virus progresses, a cat may exhibit:
  • Anemia (pale gums)
  • Jaundice (yellowing of gums or eyes)
  • Recurring bladder, skin, or respiratory infections
  • Chronic vomiting or diarrhea
  • Oral inflammation like gingivitis or stomatitis
  • Neurological symptoms—abnormal behavior, seizures, paralysis

Diagnostic Testing for FeLV

To confirm infection, the following tests are utilized:
  • ELISA Test: Detects viral proteins in blood; very sensitive
  • IFA Test: Confirms persistent infection in white blood cells
  • PCR Test: Identifies FeLV DNA, useful for detecting latent infections
Repeated testing is often recommended due to the possibility of transient or abortive infections.

Outcomes of Infection

After FeLV exposure, cats may display four outcomes:
  1. Abortive: Virus is eliminated; no illness or infectivity
  2. Regressive: Virus is dormant; may reactivate under stress
  3. Latent: Virus present in cells but non-contagious
  4. Progressive: Active infection; cat sheds virus and develops illness

Managing Infected Cats

There is no cure for FeLV, but supportive care can help manage symptoms:
  • Antibiotics for secondary infections
  • Anti-inflammatory medications
  • Appetite stimulants
  • Blood transfusions for severe anemia
  • Chemotherapy for FeLV-related cancers
Veterinary check-ups every 6–12 months are crucial. Infected cats should be kept indoors to prevent spreading the virus and protect their weakened immune systems.

Prevention Tips

Reduce the risk of FeLV by:
  • Routine testing of new or exposed cats
  • FeLV vaccination—especially in kittens and outdoor cats
  • Keeping FeLV-positive and negative cats separate
  • Avoiding shared food and litter boxes
Vaccines are effective but not 100% protective, so minimizing exposure remains essential.

Conclusion

Recognizing the first symptom of feline leukemia—typically a persistent appetite loss and weight decline—can make a significant difference in early diagnosis and care. While FeLV is serious, cats with prompt veterinary care, a clean environment, and strong owner support can still lead fulfilling lives. Always consult a veterinarian at any sign of unexplained illness to safeguard your feline companion’s health.

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