Feline Rhinotracheitis (The virus that just won't quit)
Feline upper respiratory viruses (abbreviated URV) are the bane of cats and feline vets everywhere. The most common pathogen -a cat specific herpesvirus we call feline rhinotracheitis is prevalent in the environment such that most cats will have been exposed to it and will show the chronic runny eyes, crusty noses, sneezing symptoms throughout their lifetime. For this case, I have chosen to highlight my own dynamic duo as what it is like living with a chronic URV cat.
I adopted Yoda and Mr. B 4 years ago as an ex-pair of breeding sphynxs in need of a good home. Periodically, Yoda would develop conjunctivitis (inflammation of the eye) complete with thick eye discharge and start to sound snorty and congested. As her discharge never developed the sickly yellow/green colour associated with bacterial infection, my first suspicion was that my cat was a carrier for feline rhinotracheitis – a cat specific herpesvirus that causes cold-like symptoms in cats.
How are URVs diagnosed?
Although history and physical exam will be highly suspicious of URV infection, exam allows us to narrow down disease to two viruses (herpesvirus and calicivirus). If bacterial infection is suspected then we may be concerned about Bordetella bronchiseptica (the bacteria that causes “kennel cough”) or a Chlamydia-family bacterial member. Newer technology has developed more sensitive testing that allows for virus and bacteria detection in small samples. This technology is called PCR and is considered the most sensitive for viral identification.
What is PCR?
PCR or polymerase chain reaction is a molecular lab technique where low levels of DNA to be amplified to detectable levels. In other words, we do not need a large sample (i.e. a throat or eye swab will do) or even living virus (so transport is not a factor) to get an answer! - -> PCR was used on Yoda and she came up positive for herpesviruses
How do we treat herpesviruses?
Herpesviruses are very clever. They will lie dormant in cells outwitting the circulating antibiodies designed to get rid of the virus. In other words, once you have a herpes virus infection it is there for life so treatment focuses on management and not clearing of disease. As Yoda’s disease was not that severe, I chose to treat her with probiotics. Other treatment options for herpesvirus infection include antiviral drugs (but these need to be used with caution in cats so we only reach for them in extreme cases) and lysine. If secondary bacterial infection is present then we will reach for antibiotics in those cases. It is important to keep the vaccines of all cats current as these will help maintain antibody levels against herpesviruses strong. Although the antibodies will not clear the virus, they will help limit the severity of the disease (just like a flu vaccine!).
How do probiotics help?
Probiotics are live bacteria that are ingested and mingle with the immune system at the digestive tract level. It is a cool concept that by giving my cat a probiotic (with no side effects like GI upset or risking virus resistance to therapy) I can stimulate an immune response that helps to keep the immune system strong and the virus in check. It is important to remember that not all probiotics are created equal so check with your veterinarian to ensure the right ones are prescribed in your cat.