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Understanding and Managing Upper Respiratory Infections in Cats

Causes of Respiratory Infections in Cats

Viral Infections:

  1. Herpesvirus (Feline Rhinotracheitis Virus):

  • The primary cause of upper respiratory infections (URIs) in cats.

  • Once infected, cats carry the virus for life.

  • Affects the cornea and can lead to severe eye ulcers if untreated.

  • Approximately 70-90% of cats carry the Herpesvirus.

  1. Calicivirus:

  • Vaccination is crucial as the virus can remain dormant in the nervous system.

  • Often co-infects with Herpesvirus, affecting joints, bladder, and gastrointestinal tract.

  • Can cause mouth and nose ulcers.

  • Transmitted through coughing and discharges; survives up to a week in the environment.

  1. Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV):

  • These viruses suppress the immune system, making cats more susceptible to respiratory infections.

  • Testing for FeLV/FIV is recommended before treatment.

Secondary Bacterial Infections:

  1. Chlamydia:

  • Causes conjunctivitis, often referred to as "pink eye."

  • Requires antibiotics that can penetrate the cells of the conjunctiva.

  1. Bordetella:

  • Results in runny nose, eyes, sneezing, and pneumonia.

  • Can be transmitted between dogs and cats, posing a problem in shelters.

  • Vaccination can help control outbreaks.

  1. Mycoplasma:

  • Bacteria without a cell wall that causes conjunctivitis, sneezing, coughing, fever, and swollen lymph nodes.

  1. Streptococcus:

  • Uncommon but can be transmitted from humans with strep throat to cats.

Treatment and Management of Respiratory Infections

Preventive Measures:

  • Vaccinations:

  • Essential for reducing the severity of Herpes and Calicivirus infections.

  • Vaccinated cats may still contract the virus but typically experience milder symptoms.


  • Antibiotics:

  • Commonly used to treat secondary bacterial infections in URIs.

  • Amoxicillin or Doxycycline are frequently prescribed.

  • Clavamox® for uncomplicated viral infections.

  • Doxycycline for Chlamydia and Mycoplasma.

  • Azithromycin can also be effective for Mycoplasma.

  • Antiviral Medications:

  • Famciclovir for acute Herpes flare-ups.

  • L-Lysine supplements to support immune health, especially during an active URI.

Supportive Care:

  • Eye Ointments:

  • Terramycin®, Vetericyn®, or erythromycin for soothing and healing eye issues.

  • Soft Foods:

  • Important to keep kittens eating despite oral ulcers and sore throats.

  • Heating wet food slightly can enhance aroma and encourage eating.

  • Nasal Drops and Nebulizers:

  • Gentamicin ophthalmic solution used as nasal drops to clear airways.

  • Nebulizers with saline or antibiotic solutions can help open nasal passages, especially for kittens struggling to nurse.

Key Takeaways

Managing upper respiratory infections in cats involves understanding the causes and providing comprehensive treatment. This includes vaccination, appropriate use of antibiotics and antivirals, and supportive care to address both primary viral infections and secondary bacterial complications. Regular monitoring and preventive measures can help keep cats healthy and minimize the impact of URIs.

For more detailed information and guidance on caring for cats with respiratory infections, visit

Respiratory Infections in Cats
Respiratory Infections in Cats


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