Some helpful tips on the feline community
Herpes:
The incubation period of herpes is 2-6 days. Most cats that
have recovered from herpes will be carriers of the virus for life. They shed it
intermittently under normal conditions and during times of stress. This shedding
can begin a week after the stressful incident and continue for 3 weeks
afterward. They may shed virus after recovery from illness for 3 weeks.
Calici:
The incubation period of calici virus is 1-5 days. Some cats
that have recovered from infection will shed the virus continuously for the
rest of their lives without regard to stress. 50% shed at least 75 days
post-recovery regardless of stress. Fortunately most cats do eliminate calici
virus from their bodies eventually.
Bordetella:
It is believed that there is a carrier state with
bordetella, but the mechanisms are not entirely clear yet. Bordetella has an
incubation period of 3-10 days and can be shed for 3 months post recovery.
Transmission is via direct contact, fomites and aerosol. It is zoonotic but
human cases are believed to be rare.
Chlamydophila:
The incubation period of chlamydophila is 3-14 days and post
recovery shedding can last as long as 18 months. Transmission of the organism
is either through direct contact or fomites. It is zoonotic.
Mycoplasma:
This intracellular bacteria is commonly isolated from the
oropharynx of normal cats. The role that Mycoplasma plays in feline URI has not
been fully established. Mycoplasma is passed from cat to cat via direct
transmission, with minimal transmission via fomites. It does not survive well
in the environment and it is killed by routine disinfection. Routine
disinfection and timely isolation of symptomatic cats is best to control this
disease in the shelter.
Clinical Signs
Most cats with signs of upper respiratory disease suffer
from bouts of sneezing and runny eyes. In most cases, shelters do not bother to
distinguish between the different disease causing agents. However, it is
important to make the distinction in order to design effective control
measures, such as vaccination or treatment protocols.
Diagnostic testing should be undertaken under the following
circumstances: when signs persist for over a month; signs are unusually severe
or frequent; prior to treatment with steroids; and for liability issues.
Herpes:
The lethargy, sneezing, ocular and nasal discharges may be
worse with herpes than the other diseases. Herpes is also accompanied by fever,
depression, loss of appetite, eye ulcers and drooling.
Calici:
Calici virus produces oral ulcers and lameness. These may be
the only signs or they may be seen in combination with the same signs as
herpes, only milder. There is a virulent systemic calici virus syndrome that
causes sudden death in vaccinated adult cats as well as kittens and other
animals that would ordinarily be considered protected. A description of the
syndrome can be found at the website managed by the University of California
Koret Shelter Medicine Program.
Chlamydophila:
Chlamydophila produces a serious conjunctivitis (eye
infection), accompanied by mild sneezing. This same organism may cause
conjunctivitis in humans.
Bordetella:
Bordetella is still being researched. It is believed to
cause fever, sneezing, nasal discharge, enlargement of the lymph nodes found
under the throat and loud, harsh lung sounds. Coughing may also be observed.
Mycoplasma:
This bacteria most commonly causes ocular signs including
ocular discharge and swelling of the conjunctiva.
Diagnosis
Diagnosis is generally made based on the clinical signs.
Cultures from the mouth, throat, eyes or nose may be sent to the laboratory for
confirmation. There are PCR diagnostic kits available from Idexx and Zoologix
that provide a feline upper respiratory diagnostic panel.
Treatment
Treatment for the viral diseases is symptomatic. Isolation
is essential if cats with URI are to be treated in the shelter, but placing
infected animals in foster care is a better management strategy. Good nursing
care (wiping away ocular and nasal discharges, force-feeding, keeping warm,
etc.) is essential for the comfort of these animals.
Broad-spectrum systemic antibiotics to protect against
secondary bacterial infections may be necessary because of the increased risk
of exposure in shelters, but they should generally be reserved for animals with
purulent ocular and nasal discharges, anorexia, depression, dehydration, etc.
Tetracycline, doxycycline or Clavamox are the drugs of choice to use against
secondary bacterial invasions as well as against bordetella, chlamydophila and
mycoplasma. Doxycycline is less likely than tetracycline to cause yellow
staining of the teeth in younger animals. However, doxycycline can result in
esophageal stricture, so it must be used with caution.
Ophthalmic ointment may be needed in some cases. The
ophthalmic ointment should contain an antibiotic but NOT a steroid (as a cat
may have a corneal ulcer which can be made worse by the use of a steroid
ointment in the eye). Examples of ophthalmic ointments recommended include
Terramycin, Chloramphenicol, and triple antibiotic ophthalmic ointment.
Fluid therapy may be necessary in severe cases. Antiviral
drugs may be necessary in the form of eye drops for herpes viral-induced eye
lesions. Cats who are unable to smell their food as a result of the infection
may lose their appetite and refuse to eat, so they must be encouraged by
offering foods with strong aromas, baby foods or other soft and blended foods.
It may be necessary to place a nasogastric tube to force feed them if they
continue to refuse to eat. L-lysine can also be used as a nutritional supplement
to decrease the severity of symptoms of feline URI. Steam inhalation or
nebulizers may also be helpful.
Shelters must consider carefully the resources they have
available and the risk to healthy cats when undertaking treatment. A cat who
needs only minimal treatment to recover from an upper respiratory infection may
pass it on to another cat who requires intensive care therapy. Once the shelter
has run out of space to isolate sick animals or place them in foster care, it
may be necessary to consider euthanasia to protect the lives of the rest of the
animals.
Management and Prevention
Sanitation
It is critical to disinfect the environment to control any
disease outbreak even if the pathogen does not survive long term outside the
host’s body. Except for calici virus, the respiratory pathogens are all fairly
susceptible to chemical destruction:
•Herpes virus persists outside the animal's body for only
about 18 hours and is easily destroyed by most disinfectants.
•Calici virus can persist for up to a week or longer in a
damp environment and is slightly more resistant to disinfectants.
•Chlamydophila is unstable outside the host's body and can
survive in ocular discharges at room temperature for several days.
• Mycoplasma does not survive well in the environment and is
susceptible to routine disinfection.
Cleaning protocols for cats have changed dramatically over
the past few years. Because it is well known that herpes virus reactivates with
stress, any cleaning protocol must strive to minimize stress to cats. Studies
have shown that the stress to cats that results from simply moving them from
cage to cage can result in herpes reactivation.
New recommendations are to leave cats in their enclosures
for the duration of their stay, and spot clean their cages, reserving
disinfection for when a new animal is placed in the cage. Alternatively each
cat can be assigned an adjoining cage and they can just move from one cage to
the other while their cage is cleaned. The least desirable but still acceptable
option is to assign each animal a carrier and place the cat in the same carrier
each time she is removed from her cage while it is cleaned. No other cat may be
placed in that carrier. For spot cleaning, the water bowls, food dishes, and
litter boxes are removed from the cage and replaced with disinfected items. The
cage is simply wiped down only in areas of visible soiling.
The entire cage is cleaned with soap and hot water,
including the bars in the front, sides, bottoms and tops and disinfected whenever
a new resident is introduced. The disinfectant should be applied and allowed
contact with the surface according to the manufacturer's recommendations, and
then rinsed. The cage should be completely dry before the cat is placed in it.
Sodium hypochlorite, or household bleach, is one of the most
effective and inexpensive disinfectants available for shelters to use to kill
calici virus as well as the other respiratory pathogens. If diluted 1:32 with
warm water, it is less likely to be corrosive to the cage surfaces or act as an
irritant to the cat's mucus membranes. Trifectant or potassium
peroxymonosulfate is another excellent product to use for cleaning cat cages.
It reliably kills parvo and calici virus, is easy to mix and use, and has the
advantage of having some detergent properties and of being less irritating to
mucus membranes and less corrosive to metal.
Staff, volunteers and the public should be instructed to
avoid handling or touching animals during outbreaks especially. They should
wash their hands thoroughly after each contact and wear protective garments.
Shelter Design
Cage placement and ventilation have a lot to do with the
spread of disease. A cat's sneeze can travel about 3-4 feet, so it is important
to have cat cages at least 4 feet apart if they are facing each other. Shelter
traffic patterns should place as much distance as possible between sick wards
and healthy ones. Staff who clean and work in several areas should start in the
areas with healthy juvenile and susceptible animals and end in the areas with
diseased animals.
Lack of adequate ventilation also plays a key part in
disease spread. If an air exchange system is employed, there should be a
minimum of 12-15 air changes per hour, preferably with outside air. If not,
circulation patterns should go from healthy areas and kitten areas to sick
areas. HEPA filters may be helpful in refreshing the air, but should not be
relied on to counter inadequate ventilation systems. Avoid ozone and ion
generators.
Fresh air is also extremely valuable in reducing incidence
and severity of feline URI in shelters. Ideally, isolation areas as well as cat
holding areas should have windows with screens that open to the outside, and
these windows should be open when weather permits.
Disease Outbreak Management
The following other measures should help prevent and
minimize the impact of upper respiratory infections:
•Examine all animals on intake.
•Isolate sick animals immediately.
•Vaccinate on intake all cats beginning at 4-6 weeks of age
with a modified live vaccine for feline herpes (rhinotracheitis), calici and
panleukopenia (FVRCP), with boosters every 2 weeks until 16-18 weeks of age.
•Adult cats may be given one injection, but a booster 2
weeks later should be considered in a high risk situation.
•Consider using an intranasal vaccine if URI is a real or
persistent problem. Many shelters report excellent results in reducing the
incidence of URI when switching vaccines from the parenteral (injectable) to
intranasal product. Intranasal vaccines can be used in animals as young as 3
weeks of age if using the bivalent product against calici and herpes virus. The
main advantage is that a faster immune response is seen compared to use of the
injectable vaccine. The main drawbacks with the intranasal vaccines are that
they are harder to administer and cause side effects that mimic actual clinical
disease. The difference is that the animals with vaccine reactions still appear
well and only sneeze and have runny eyes for a couple of days. Adopters of
animals who have been given this vaccine should be advised of the side effects
so they and their veterinarians will know what to expect. (If using an
intranasal vaccine to prevent feline URI, a subcutaneous panleukopenia vaccine
is still needed to prevent feline distemper. The panleukopenia vaccine is
usually combined with calici and herpes virus, and this multivalent vaccine can
be used in addition to an intranasal vaccine).
•Although there is still debate regarding whether or not
bordetella is a primary cause of disease, some shelters report a decrease in
the incidence of URI after using the intranasal bordetella vaccine. Positive
cultures of bordetella should be obtained before using this product.
•Deworm kittens and cats routinely with a broad spectrum
anthelmintic.
•Feed the best diet affordable, and for individual needs.
•Segregate kittens by litter and age groups. Kittens under 3
months of age are most susceptible to disease and should be separated from
other litters and from adult animals, or placed in foster care until the
outbreak is under control.
•Disinfect water bowls daily and between usages by different
animals.
•Instruct staff, volunteers and visitors about spreading
disease via fomites.
•Use hand sanitizers with 70% alcohol. Hand washing remains
best.
•Post signs asking the public to prevent disease spread by
washing their hands and to avoid handling animals without staff supervision.
•Use disposable litter pans, toys, cleaning cloths, food
dishes, etc.
•Restrict the use of cleaning materials to individual rooms
or wards.
•Launder uniforms in hot water, detergent and bleach.
•Reduce stress!
•Avoid crowding, loud noises.
•Consider colony housing in addition to conventional
individual cages for some cats.
•Provide bedding, toys, perches and hiding places.
•Establish a routine for cleaning and other procedures.
•Maintain comfortable environmental conditions, evaluating
temperature, humidity and ventilation in every animal holding area.
•Turn the lights off at night so animals can sleep.
•Provide access to natural light.
•Place mildly affected animals in foster homes where
treatment can be continued without exposing all the animals to risk of
infection.
Credits: Lila Miller, DVM
