Guidelines for Preventing Canine Distemper Transmission During High-Risk Events

Animal Shelters

• Alert the public that risk of distemper transmission is higher than usual
• Owners should assure that their dogs and ferrets are up to date on vaccines, even if they do not believe their pets encounter other animals

• Discourage dog relinquishment to the shelter as risk of exposure is highest in dense populations of dogs

• For dogs that must be relinquished to the shelter, encourage vaccination of dogs at least 2 weeks prior to admission

• Vaccinate all dogs 4 weeks or older at admission to the shelter
• Vaccinate immediately at intake, even if other intake procedures cannot be performed until later
• Give a booster vaccine to all dogs 2 weeks after the intake vaccine
• Puppies should be vaccinated every 2 weeks while in the shelter
• Vaccinate sick, dangerous, and unadoptable dogs even if there is little chance of live release to assure there is no vulnerable reservoir for infection and to create “herd immunity”
• Use only modified-live or recombinant distemper vaccines
• Store and handle vaccines according to manufacturer’s instructions

• Protect puppies, the most vulnerable population, from exposure to distemper
• Develop diversion programs to avoid admitting puppies to the shelter
• Transfer immediately to foster homes or rescue groups
• Discourage relinquishment of puppies to the shelter
• Encourage relinquishers to claim ownership of puppies to avoid invoking a legal stray-holding period
• House puppies in a separate area from adults
• Avoid retaining puppies in the shelter for adoption if rescue groups can remove them earlier

• Create areas for housing adoptable dogs that are separate from dogs still in the legal stray-holding period

• Avoid crowding and co-mingling
• Crowding and co-mingling of dogs increases potential for exposure to infectious agents 
• Crowding and co-mingling increases stress, which reduces resistance to disease
• Crowding impedes the ability of staff to properly care for dogs and to keep the facility clean and sanitized
• Crowding impedes the opportunity for daily observation of dog welfare, attitude, appetite, and early signs of disease

• Establish a system of daily rounds during which trained personnel evaluate each dog in the shelter for early signs of infection
• Discharge from eyes or nose, cough, listlessness or apathy, vomiting and diarrhea, disorientation, tremors, “fly biting,” seizures
• Suspect animals should be immediately removed from the general population
• Swabs should be collected for PCR diagnosis of distemper in suspect animals
• Written records should be maintained of any findings during daily rounds

• Care for the most healthy and vulnerable dog populations first to avoid spreading the virus
• Healthy puppiesà healthy adultsàsick dogs à wildlife
• It is rarely possibly to adequately isolate dogs with distemper in animal shelters. In most cases, treatment should not be attempted because housing infected dogs in the shelter creates a high risk of transmission to other dogs
• Wildlife vectors of distemper should not be maintained in the shelter or on the shelter grounds

• Utilize an effective cleaning and disinfection protocol
• Luckily, distemper is relatively easy to inactivate compared to more durable viruses such as parvovirus
• All visible organic matter such as feces, vomit, and respiratory secretions must be removed BEFORE disinfectants are applied or the chemicals will not work
• Quaternary ammonium products (KennelSol, Parvocide, Roccal, Broadside, etc), Trifectant, freshly diluted 1:32 bleach, Wysiwash, and Virox are all effective against distemper
• Disinfectants must be applied to all surfaces (including hard to reach areas like the back of cage bars and chain link barriers) for appropriate contact times, usually 10 minutes for most disinfectants
• Footbaths are ineffective and only serve to spread germs

• Wear personal protective outwear and boots and disposable gloves when caring for animals and cleaning kennels
• Change  outerwear and boots before moving from one segregated population to the next
• This is especially important after handling dogs suspicious for infection or handling wildlife
• Change outwear and boots before returning home to personal pets

• Staff , vehicles, and equipment rapidly become contaminated with distemper virus after handling infected animals, even if they do not appear to be sick
• Designate specific vehicles and animal control officers to respond to sick wildlife and DOA disposal calls and aother vehicles and staff to respond to calls regarding dogs to avoid cross contamination
• Disinfect vehicle compartments, catch poles, carriers, traps, leashes, etc., after each use, regardless of what species is involved or whether animals appear to be sick
• Staff handling wildlife or sick animals should not handle dogs for the rest of the day

• Adoptions may continue as long as distemper is not spreading in the shelter
• Resident pets in adopter homes should be confirmed to have current vaccinations before the new pet comes home

Rescue and Foster Groups

• All of the principles for preventing distemper in shelters listed above also apply to rescue and foster groups

• Avoid introducing distemper virus to the rescue population
• Carefully examine dogs for signs of distemper prior to admitting them to the program
• Avoid transferring animals and mixing from multiple different sources or agencies
• Keep newly transferred dogs separate from other dogs for at least 2 weeks
• The incubation (asymptomatic) period can last 2 weeks or more during which infected dogs appear healthy but are infected and contagious to other dogs
• This quarantine period allows time for infected dogs to develop signs of disease without infecting other dogs in the meantime
• This quarantine period allows time for intake vaccines to take effect

• Vaccinate all dogs on intake, regardless of past history of vaccination
• Repeat vaccination of all dogs 2 weeks later
• Puppies should be vaccinated starting at 4-6 weeks of age and revaccinated every 2 weeks until they are older than 4 months

• Avoid transmission of distemper within the rescue population
• Keep each litter of puppies in separate foster homes if possible
• Assure that foster families have only healthy vaccinated pets at home and are not fostering for other groups at the same time
• Avoid crowding for reasons mentioned above
• Keep foster animals in areas with readily cleanable surfaces such as vinyl or tile floors
• Bring only healthy animals to adoption events

• Seek veterinary care for sick dogs
• Specific testing described below can provide reliable diagnosis of respiratory and gastrointestinal infections in only a few days
• Other more treatable infections can mimic distemper, so knowing the precise cause of illness can allow appropriate treatment and management to stop spread of disease
• It is not possible to differentiate distemper from other diseases based solely on the thickness or color of nasal discharge or any other clinical signs

Dog and Ferret Owners

• Check with your veterinarian to assure your pet is up to date with vaccinations
• Do not allow your pet to have contact with other animals you are not familiar with
• Verify that boarding kennels, doggie day cares, dog parks and other locations refuse sick or unvaccinated dogs before admitting your pets
• Have your pet evaluated by your veterinarian immediately if you notice anything unusual with its health or behavior
• Report sick wildlife to animal control officers

Diagnosis of Distemper

• PCR diagnostic sampling should be supervised and interpreted by a veterinarian

• The preferred diagnostic test for distemper is PCR
• This test detects the viral nucleic acid sequences, confirming that distemper virus is present
• Samples are easily collected by swabbing  the conjunctiva (inside of the lower eyelid) and nasal passage
• Several diagnostic labs offer PCR tests for distemper in addition to other pathogens that cause respiratory infections such as canine influenza and Bordetella bronchiseptica. Currently, Maddie’s Shelter Medicine Program uses IDEXX Laboratories for PCR testing.
• Samples from the lungs or brains of dogs that have died can also be submitted for PCR testing
• False-positive results can occur in some dogs that have recently been vaccinated since the PCR test can detect the virus in the vaccine. This does not occur with the recombinant distemper vaccine from Merial.
• Ideally swabs should be collected from animals in the acute phase of clinical disease (<7 days) since the amount of some pathogens in the upper respiratory tract can decrease after this time period, especially canine influenza and canine respiratory coronavirus. In contrast, canine distemper virus is shed for long periods of time so swabs can be collected from dogs that have been ill for more than 7 days.
• For shelter disease surveillance, swabs should be collected from several animals, including those with clinical disease and those exposed but without clinical signs.

• Sample collection and submission
• Supplies needed
• Dacron swabs (2/dog)
• Sterile plastic or glass submission tubes (plain red top blood tubes work well)
• Plastic baggies (1/dog)
• Disposable exam gloves (1 pair/dog)
• Laboratory submission form
• Styrofoam shipping cooler with ice packs (1/shipment)

• Prevent cross contamination
• PCR is a very sensitive diagnostic tool for identification of nucleic acid of respiratory pathogens on swabs. Care should be taken during collection of samples to avoid contamination by nucleic acids on hands. Clean exam gloves should be worn during collection of swabs and the gloves should be changed between EACH ANIMAL to avoid cross contamination.
• If performing surveillance, always collect samples from the healthy animals first and the animals with respiratory signs second to avoid cross-contamination.
• Sample collection
• Two swabs should be collected from each animal and pooled together in one dry sterile sample tube to maximize detection of any respiratory pathogens.
• For each dog, collect a conjunctival swab and deep nasal swab and place both swabs in the same dry sterile tube to be processed together as one sample. If the dog will not permit a nasal swab, you can substitute a pharyngeal (throat) swab, but this is less ideal.
• For the conjunctival swab, pull a lower eyelid away from the eyeball to expose the conjunctival sac. Insert the tip of the swab into the sac and gently rub to remove the epithelial cells. Most animals tolerate this procedure very well. Open a clean sterile tube, insert about one-third of the swab stick, then snap the plastic handle so that it breaks and the swab tip falls into the tube. Close the tube tightly.
• For the deep nasal swab, insert the swab tip as far into a nostril as possible and rub to remove epithelial cells. Most dogs will tolerate this once, but may not hold still for additional attempts.
• For the deep pharyngeal swab, ask an assistant to open the mouth. Then vigorously swab the back of the oropharynx near the tonsils, taking care to avoid the tongue and heavy saliva contamination. Add this swab to the same tube with the conjunctival swab.
• To avoid cross-contamination, label each tube with the animal’s ID using a permanent marker such as a Sharpie pen, snap the cap tightly, and drop the tube into its individual baggie before changing gloves and moving on to the next animal. Label the outside of baggie as well.
• Sample packaging
• Once the swabbing is complete, the individual sealed baggies should be placed together in a larger baggie and stored in the refrigerator (not frozen) pending submission to the lab. No liquids should be added to the swabs or tubes. The samples should be submitted as soon as possible after collection.
• The IDEXX canine respiratory pathogen PCR panel is test code 2524. More information is available at www.idexx.com/pcr
• The laboratory requisition form should be sealed in its own baggie to protect from moisture and included with the sample packaging
• Sample submission
• Several diagnostic laboratories offer a courier service for pickup of diagnostic samples in most areas.  The courier can transfer the samples and completed submission forms to the lab.
• In areas where there is no pickup service, the samples can be packed in a Styrofoam shipping container with frozen ice packs to keep the samples cool but not frozen, then shipped via an overnight courier such as FedEx or UPS to the lab (not the US Postal Service).

Additional Information 

Veterinarians from Maddie’s® Shelter Medicine Program are available to provide additional information regarding distemper virus and other infectious disease threats. We want to help you keep your shelter pets healthy and happy while on their way to their forever homes.

Contact Us

(352) 273-8660

sheltermedicine@vetmed.ufl.edu