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!

Just Do It! Rabies Vaccination

My veterinary clinic received a call from a frustrated dog owner late Friday afternoon. Her dog was coughing and refused to eat after spending a mandatory ten days in a local shelter under rabies quarantine after biting someone. Her bill for quarantining her dog was over $200. On top of that, now her dog was very sick and faced additional costs for diagnostics and treatment. All this could have been avoided with a comparatively inexpensive examination and rabies vaccination!

Rabies is a disease not to be trifled with. Because rabies disease poses a significant threat to human health, public officials take bite cases involving dogs and cats as well as wild animals very seriously. Wisconsin law requires pet dogs, cats and ferrets that have bitten a person to be quarantined for ten days and examined by a veterinarian three times during this period to monitor for signs of rabies. Although rabies virus is typically transmitted through bite wounds, it is also rarely spread through contamination of open wounds, abrasions, mucous membranes, or scratches with saliva or other potentially infectious material (neural tissue, cerebrospinal fluid, salivary gland tissue). This means that even if a mere cat scratch results in medical intervention for the person scratched, the injury may need to be reported to the authorities with orders to quarantine.

Here's the catch. If the pet is current on its rabies vaccination, the quarantine can occur in the owner's home. If the pet's rabies vaccination has lapsed the quarantine must be in an approved facility such as a veterinary clinic or shelter at the owner's expense. And either way the pet needs to be examined three times by a veterinarian.

Dog showing signs of rabies during quarantine

Animals that develop neurological signs during the quarantine period are humanely euthanized and their brains are submitted to the state diagnostic laboratory for testing. If the animal's brain tests positive for rabies the injured person needs to undergo rabies prophylaxis, the series of injections to prevent development of rabies disease. In the past, these injections were administered into the person’s abdomen. Nowadays, the injections are given in the arm, not much different from getting a tetanus or flu shot!

Did you know?

• Rabies occurs in more than 150 countries and territories. Rabies is found on every continent on Earth except Antarctica!
• Worldwide, more than 55,000 people die of rabies every year. Nearly half of those bitten by rabid animals are children!
• Dogs are the source of 99% of human rabies deaths.
• In the United States, raccoons, skunks, bats, and foxes are common wildlife carriers of rabies. Among domestic animals (besides dogs, cats and ferrets), cattle, horses, swine and other livestock can also be affected by rabies virus.
• Not all rabid animals show the classic foaming-at-the-mouth “mad,” or furious form of rabies. Some rabid animals display the paralytic or “dumb” form of rabies, and may appear to be choking on something. Human exposure in these cases often occurs when a well-meaning person reaches into the animal’s mouth to clear the obstruction!
• Wound cleansing and immunization within a few hours after contact with a suspect rabid animal can prevent the onset of rabies and death.
• Every year, more than 15 million people worldwide receive post-exposure preventive injections to avert the disease – this is estimated to prevent 327,000 rabies deaths annually.

The Center for Disease Control (CDC) provides a good overview on rabies disease. Also, the American Veterinary Medical Association (AVMA) has created an entertaining and enlightening video on rabies which is appropriate for educating young people about the dangers of rabies. 

Just do it! sums up my feelings on rabies prevention. Keep all pets -- even indoor cats -- current on their rabies vaccination. Educate yourself and the children you love about rabies disease prevention. In the case of injury from an animal -- especially wildlife or stranger -- contact the local authorities (police, animal control, physicians, veterinarians) for assistance in determining whether quarantining, testing or prophylaxis is necessary. 

If You Give a Vet a Soapbox...My Response to the Anti-Vaccine Movement

Moments ago I finished -- with a dramatic flourish -- an e-mail response to a very good client whose insightful questions about his pets constantly keep me on my toes. What started as a quick note developed into a lengthy and impassioned epistle. I found myself so wound up by the time I hit "Send" that I couldn't help but expound my point of view to anyone who would listen. Dear reader, that may be you if you choose to continue.

Hey Dr. Kim,

Not sure if you saw the attached article or not. It was a good read I think, and thought you may find it interesting. All is well with Puppy. We will see you in a few weeks for another check up with him. Hope your weekend was well! 

Thanks,

Puppy Owner

Subject: puppy vaccinations

I found this link that may be of interest to you now that your puppies have just received their second shot. This is a very important read, for you to discuss with your vet.

The puppies will be ready for their rabies shot in a couple weeks but according to this article which has some very strong articles to support, there is no need for anything more than rabies this year.

Know that I gave the parvo/distemper shot to them at home at 7 1/2 weeks old. There were not exposed at the vet's office. This is the safest way/time to give a vax not knowing what all the puppies would be exposed to as they went to their new homes....

Kindest regards~
Puppy Breeders
http://www.dogsnaturallymagazine.com/five-things-your-vet-says-that-arent-true/

Dear Puppy Owner:

I'm glad you sent the article. I could read on this subject for hours, clicking links to this and that!

So much of the article is correct. As I read it, though, I felt myself waiting for the author to complete a train of scientific thought as I learned in immunology training [the study of the immune system]. And when they didn't I realized it must be because the omitted part would actually lessen the effectiveness of their argument. There are so many points in the article where I wanted to shout "But that's not the whole story! You forgot about individual variation or herd health medicine or maternal antibody variability or compliance or practicality, economics and human fallibility!" 

People mistakenly believe the practice of immunology in human and veterinary medicine is done in favor of the individual. Vaccination critics believe an individual's risk outweighs the public's benefit. But the cold hard truth is immunizations are not done solely for the best interest of the patient but for the public interest.

A dog is not vaccinated against rabies to protect him from dying of rabies (although he indeed benefits in this way). A dog is vaccinated against rabies to create a barrier of protection to the human population from rabid domestic animals. If animals who interact closely with the human population (such as dogs) cannot contract and pass the rabies virus, then fewer humans will die of rabies. That is the goal of rabies vaccination in pets. A corollary argument is that a dog vaccinated against parvovirus (or distemper, etc.) helps protect the whole population of dogs from parvovirus. Just as parents who refuse to vaccinate their children are relying on "herd immunity" (i.e., the fact that the U.S. population is well vaccinated against certain deadly illnesses) to protect their unvaccinated children, pet owners who do not vaccinate have relatively "protected" pets because the animals they interact with are vaccinated and cannot pass on disease.

I could write a dissertation in response to the arguments laid out in the article! But I do want to point out two things regarding the Breeder's e-mail and how it relates to Puppy:
1) Puppy Breeder's email says the pups were vaccinated against parvo/distemper at 7-1/2 weeks and do not need any further shots besides rabies. This statement does not even agree with the article much less current standard of practice. The article says a single vaccine at 12 weeks is sufficient, not one prior to 8 weeks of age. 
2) Dr. Ron Schultz's research is quoted extensively in the article in support of vaccinating only once at 12 weeks. Dr. Schultz was my immunology professor at UW School of Veterinary Medicine. [I am a 2007 DVM graduate.] We were taught to make sure the final "distemper" vaccine was given at or after 16 weeks (not 12). 

There are many scientifically proven reasons for boostering more than once in puppies. There are different types of immunity and boostering increases long term "memory" in the immune system. Also, maternal antibodies interfere with vaccination in puppies. That's why puppies (and babies) receive a series of vaccines. The reason we do not wait until 12-16 weeks is because we cannot be sure a) whether the mother was properly vaccinated and b) whether the puppy/baby received enough immunoglobulins through first milk colostrum (a bigger risk in large litters where pups fight for resources). 

Over-vaccination is a real concern, but I do believe in the societal and clinical benefits of vaccinating my pets as well as my children. Some vets (as indicated in the article) recommend annual vaccination for everything, but this method of practice is changing. Dr. Schultz taught us that many pets have more than 1 year (and even more than 3 years) of protection from vaccination, it's true. Many viral vaccines are FDA licensed for administration every 3 years. Until new research and licensing shows protection for a majority of animals beyond 3 years, most vets will vaccinate every 3 years for rabies and "distemper." Yes, you can have antibody levels tested for parvovirus or distemper virus and choose not to vaccinate if levels remain high. However, this is not commonly done because the serology test is not inexpensive. 

Some types of vaccines (for bacterial diseases such as Lyme, Leptospirosis and Bordetella) do NOT provide proven protection much beyond one year. In fact, Bordetella is sometimes given every 6 months to dogs at high risk for Kennel Cough because the body does not make the same long lasting immunological response to bacterial diseases as it does to viral disease. (This probably explains the recent Whooping Cough outbreaks in humans...Whooping Cough is related to Kennel Cough; both are caused by Bordetella organisms!!! As children we receive the "Pertussis" vaccine but lose protection over time and may become susceptible as teenagers or adults.) The canine vaccines I just mentioned are lifestyle vaccines. Not all dogs should or do receive them.

Whew. I'm exhausted. This is such an emotional topic from either side! I find it interesting that the same diseases "anti-vaccine people" claim stem from vaccination in this article are the same diseases "anti-grain pet food people" claim stem from commercial diets. It would be foolhardy of me to say any of these claims are complete nonsense! There is so much we do not fully understand of the intricate workings of the body and our environment. There are many truthful statements in the article. Good physicians, veterinarians, and scientists continually study and learn. Good doctors pay attention to what works and what doesn't, rely on a body of properly done objective studies (believe me, anyone can do a study to prove what they want to prove!), and think about the whole picture when it comes to health and disease management.

I would be happy to discuss the article, my comments and any additional questions you may have at Puppy's visit next week!

Dr. Kim 

Shortly after my earnest e-mail shot through cyberspace, my kind client responded with a mildly exasperated yet placating e-mail, soothing my raging frustration. I didn't have much convincing to do apparently. As long as such mental gymnastics don't give me a coronary, I'll just be grateful for the chance to debate interesting and important topics with other people who care. 

Leapin' Livers! Leptospirosis and Other Liver Problems

I am exhausted. And demoralized.

Since late Thursday evening I have been caring for a critically ill terrier on intravenous fluids. Up every couple of hours each night for potty breaks, medicating and TLC. During the in-between times watching "Doggie TV", my closed circuit camera system broadcasting the antics of hospitalized pets to the comfort of my couch (not very stimulating programming...lots of sleeping going on in the clinic!) Just when I thought he was ready to go home on Saturday, he started to relapse.

Denny* is a six-year-old Cairn terrier who presented for vomiting, diarrhea and not eating. Extensive bloodwork and fecal tests all pointed toward acute liver failure. The liver is a very important organ that comes under attack from all sorts of day-to-day insults. Although the liver has hundreds of vital functions, one function is an all around "detoxifier." Everything that passes through the lips of an animal is dealt with by the liver:  bacteria, viruses, toxins, medications. Most of the time anything with potential to harm is effectively neutralized and silently excreted from the body. Sometimes the liver's defenses are overcome and the animal becomes ill. Luckily the liver also has great regenerative potential, so with some intensive care, elimination of the inciting cause, and time, many of these animals recover fully.

Electron micrograph of Leptospira bacterium

Due to his age and vaccine status, Denny was first suspected of having a bacterial infection in his liver called leptospirosis. This organism is shed in the urine of infected wild animals such as racoons or domestic animals like cattle and dogs. The infection is acquired by drinking contaminated water or snuffling around an area where another infected animal has urinated (the bacteria can pass through mucous membranes such as lips, noses and breaks in the skin). Leptospirosis is a zoonotic disease, meaning people can catch it from their infected animal. Some animals become very sick from liver or kidney disease, while others are asymptomatic carriers of the disease, shedding the bacteria wherever they urinate! Yikes! Although leptospirosis is treatable with common antibiotics, if the infection has triggered widespread inflammation in the system the animal may not respond to treatment.

While there is a specific test for leptospirosis, it takes time to run at the outside laboratory and Denny needed treatment immediately. We started him on intravenous fluids to help flush the buildup of liver toxins from his bloodstream, anti-vomiting medications and antibiotics. By Friday evening he was able to keep down water, small amounts of food made for liver failure patients, and oral medications. He was perky and stronger than when he arrived Thursday evening. He even lifted his leg to pee!

On Saturday morning I made preparations for sending Denny home. But by the afternoon, Denny refused to drink and started vomiting again. And his diarrhea returned, a bright orange color signaling continued problems with his liver. Still bright, Denny clearly is not improving enough to go home.

My heart is sinking. It's not the normal progression of things for uncomplicated leptospirosis. Other differential diagnoses are spinning through my mind as I try to make sense of Denny's disease. Does Denny, though not old, have a liver tumor? Does he have leptospirosis or other infection complicated by raging hepatitis? Does he have a heretofore asymptomatic congenital liver disease such as a shunt, a condition where blood loaded with nutrients and waste products bypasses the liver processing center? I'm dwelling a lot on this last one because I know more about his genetic background than I do most of my patients. His parents are my patients too. And they are nearly twice his size!

Portography, a special imaging technique, showing a
large liver shunt. A special dye is injected into the splenic
vein (from right of image) which then travels to the liver.
Here the dye mostly bypasses the liver (middle)
straight back to the heart (left of image).

This size difference worries me because dogs born with liver shunts are generally smaller than their counterparts and may be "poor doers" throughout life. Severely affected animals may show symptoms early on, but some pets find a way to compensate for the disease and may have little to no sign of disease for years. Maybe they do poorly under anesthesia at the time of spaying or neutering. (This is why preanesthetic testing is so important...to catch any early signs of liver problems before anesthesia.) Maybe they are intermittent pukers or have other easily overlooked symptoms of illness throughout life. Maybe as adults they just have some unexplained liver elevations on wellness blood screening and are acting perfectly happy otherwise.

Denny's owner allowed me to speak with the breeder, who has been able to keep tabs on most of her puppies long after adoption. Turns out Denny was diagnosed with a temporary heart murmur in early puppyhood which later resolved. In addition to being petite, Denny has been intermittently vomiting for years, a medical problem unique to him among his canine family members. She also reports that Denny's brother died at age 5 from a vague illness involving his liver!

Because liver shunts require specialized imaging or invasive biopsies for definitive diagnosis, the expense of which is outside most families' reach, we are left with more questions than answers oftentimes. I'm not sure how Denny's situation will resolve. Time is the nearly magical ingredient in so many of these tough cases. Denny's owners are committed to giving him a good chance, so we will continue IV fluids and symptomatic medications for now, buying his liver more time to rest, regenerate and recover if possible.