Herpes Virus: Putting the "Crud" into Recrudescence

For the past week I've been battling a hideous cold sore on my upper lip which puts me in the frame of mind to discuss upper respiratory infections in cats. If that seems like an incongruous association it may help to understand that both conditions are caused by a herpes virus. Human cold sores result from infection with Herpes simplex virus type 1 (HSV1) while many cats with chronic or recurrent upper respiratory infections have feline herpesvirus-1 (FHV1).

Most cold sore sufferers contracted the virus in early childhood (often before the age of seven). Approximately 80% of Americans have been exposed to HSV1. Similarly, FHV1 infections are usually acquired during kittenhood with 80% of the cat population being affected.

HSV1 is spread from person to person through kissing or through sharing drink glasses, utensils, lip gloss, toothbrushes, and so on. Self-infection, or spread from a primary oral location to other parts of the body (eyes, fingers, etc.), can happen by touching the sore and not washing hands properly. Yikes! In cats, FHV1 spreads by direct contact with infected ocular or nasal secretions. The virus can be transferred on a caretaker's clothing or inanimate objects (this is called "fomite" transmission) from sick cats to healthy ones which contributes to herpes virus epidemics in humane societies and shelters. Unlike Kennel Cough in dogs, feline herpes is unlikely to spread far through aerosolization of virus via sneezing or coughing.

Symptoms of feline herpesvirus include fever, sneezing, nasal discharge and conjunctivitis in the eyes. Some cats are left with permanent damage in the affected eye with reduced vision from scar tissue. Occasionally infection in the eye is so severe that surgical removal of the eyeball is required!  Bacterial infections secondary to the feline herpesvirus are common causing secretions to become thick and greenish. Pneumonia is uncommon but possible.

Cold sore symptoms begin as a tingling in the skin then progress to blistering and then a scabby wound. Cold sores usually occur around the mouth but can affect the nostrils, chin, cheeks and even eyes. Interestingly, I just learned that cold sores are not canker sores! Canker sores are non-contagious ulcerations affecting the lips and soft tissue inside the mouth caused by stress, injury, allergy or bacteria.


If you've ever suffered from a cold sore you understand that it tends to reappear in the same spot each time and often emerges during times of stress or illness. This is because, unlike romance, herpes lasts forever. Seriously. Once infected, the body begins fighting a guerrilla war it can't win. The virus goes into hiding or hibernation on a particular nerve pathway until it senses weakened immune defenses resulting from another illness, exhaustion or injury. Then it creeps to the skin surface to wreak havoc and reproduce.

Many adult cats brought into my veterinary clinic for evaluation and treatment of a "cold" actually are showing reappearance, or "recrudescence," of their herpes virus. In cats, anything from the stress of a new family member to serious organ failure can lower the immune system awakening the latent herpes virus. I have found that treating the underlying problem in these cats hastens their recovery from the viral upper respiratory infection.

Fortunately for cats, vaccination against FHV1 (also called feline rhinotracheitis) is available to lessen  severity of symptoms as well as reduce the spread of the virus. Vaccination for FHV1 is usually given as part of a combination "distemper" vaccine, which includes protection against several other feline diseases. There is no vaccine available to prevent or lessens symptoms of cold sores from HSV1 in people.

Because herpes is a virus, antibiotic therapy is unnecessary and inappropriate unless a secondary bacterial infection has developed. Duration of a cold sore outbreak can last 8-12 days in people. Several special ointments have been developed to shorten the duration of the outbreak. Healthy living, sun protection and immune boosting supplements may help prevent recurrence.

I have seen symptoms of feline herpes virus drag on for weeks to months. A non-resolving upper respiratory infection in a cat may be a warning sign of an underlying illness or lowered immune system. Unfortunately, some severely affected cats are left with permanent damage in their eyes and nasal passages that predispose them to a lifetime of weepy eyes, gooey noses and frequent bacterial infections. Several of the anti-viral medications available for humans have been used to treat feline herpes virus infections: some can be effective while others cause serious side-effects. Never give your cat any human medication without first checking with your veterinarian! L-Lysine is regularly used in cats to inhibit replication of the virus and speed recovery. While L-Lysine is available over-the-counter, check with your veterinarian for dosing instructions.

People often suggest to me that their cat gave them a cold (or vice versa), but this is highly unlikely. While cats and humans may both be plagued by a herpes virus, subtle genetic differences between the different strains dictate which animal can be infected and how. So if you come down with a cold sore, please don't blame your kitten--even if you have been planting lots of kisses!

It's Not a Deterrent, It's a Medieval Torture Chamber

My first and only exposure to "sticky mouse traps" was years ago, during my first week as a veterinarian. A distraught woman rushed into the clinic and presented me with a palm-sized square plastic tray with a little sparrow stuck to the adhesive, its feathered breast heaving in panic. The sticky trap had been placed in a garage, its intended target invading mice. The hapless bird had wandered onto the insanely sticky trap and been unable to wander off.

With the delicate precision of a surgeon, I painstakingly pried individual feathers and fluff from the glue. Unfortunately, but as intended by the trap's design, the more the bird struggled in its effort to escape not only the trap but also me, the more of its surface area became firmly attached to the glue. The desperate struggle (also part of the trap's design) was killing the fragile little bird by exhaustion as surely as the inescapable glue would eventually lead to deadly dehydration and starvation. It eventually became clear that the only good option for this little sparrow was a rapid and humane death by injection of euthanasia solution.

It was a sad end for the sparrow, but I could not help but think even then what a medieval torture chamber the sticky trap must be for the intended victim -- the rodent. To become hopelessly entangled in glue, uselessly struggling for escape, finally dying after hours or days from exhaustion and dehydration -- what a horrible death even for a rodent pest! 


And now I have learned from Aves Wildlife Alliance that my sparrow-sticky trap experience is not unique to me. In fact, sticky traps are marketed as a humane bird deterrent. Not death trap....deterrent. There are plenty of good reasons to want to deter birds and rodents from the home, but as with anti-coagulant poisons, it is becoming increasingly obvious that we must think beyond the intended target of our pest deterrents and traps to innocent bystanders such as pets and wildlife.

What follows is a blog by Rebekah Weiss of Aves Wildlife Alliance on the dangers of sticky traps for birds. We can't get away from pest deterrents, but we can choose humane deterrents.

For the Birds…or Maybe Not

Posted on April 2, 2013 by Rebekah

During the spring and summer seasons many of our bird friends are very busy building nests.  Sometimes our porches, light fixtures and outdoor decorations can be as appealing to bird families as the neighboring trees.  If you don’t mind using your back door for a couple of weeks you can enjoy watching the busy pair build their nest, lay eggs and raise their young.  If you would rather they not take up residence under your roof, there are a variety of ways to let the nest builders know your house is not open for birdy renters.

Please avoid Bird Repellent Gels, Pastes or Sticky Strips.  These products are marketed as non-toxic and safe for birds.  Here is an excerpt from one product, “A non-toxic, tacky bird repellent gel.  Can be used on ledges, sills, beams, rafters, signs, statues and hundreds of other outdoor surfaces to prevent pest birds from roosting. The gel does not harm birds – it simply makes surfaces uncomfortable, intimidating and uninviting.”  The reality is these products are not safe and do cause often deadly harm to the unsuspecting birds.  The sticky material coats the bird’s feet and any feathers it comes in contact with.  Small birds often struggle to the point of exhaustion to free themselves while larger birds may lose their ability to fly as a result of the glue on their feathers.  Despite what the label says, these products harm birds and are not safe!

This adult Eastern Screech Owl landed on a surface coated with one of these bird repellent gels.  He could not open his wings or his feet and would have likely starved had he not been found by a concerned home owner.  This little owl will be at the Aves hospital for several weeks while he molts out the sticky feathers and grows in new.

Bird Safe Alternatives:

Wedge a tennis ball or two in between the house and your outdoor light fixtures to keep your lights bird nest free.

Use ½ x ½ inch hardware cloth to close off any openings along the soffits, eves or under open porches of your house.

Use an angled piece of cardboard over ledges.

These items can be safely removed when the pair takes up residence elsewhere and does not cause any damage to your home or to the birds.