Page 109 - JRT Magazine - 2023 Issue 2

Canine Herpes virus (CHV1)
The family of Herpes viruses may cause disease
in many species of animals, including humans.
Characteristic for this group of viruses is that
after an acute infection, the virus will remain
in the body in a resting state and can be re- dogs are mating. It does not survive outside
activated in connection with all kinds of stress.
Well known in humans is the stress-related
flare up of lip ulcers caused by Herpes Simplex.
Canine Herpes Virus 1 (CHV1) only occurs
in dogs. This virus is widespread in the dog
population in many parts of the world, and
between 40% and 88% of tested dogs have
been found to have antibodies against CHV1,
which shows that they, at some time, have been
infected with this virus (Krogenaes et al., 2012;
2014).
In dogs older than 12 weeks, mild respiratory
disease is the most common clinical sign.
However, adult dogs that become infected
with CHV1 may also develop inflammation of
the sclera of the eye and an infection of the
genital tract – sometimes with small blisters
in the vaginal or preputial mucosa. Abortions
have been seen in pregnant bitches after
experimentally induced infection, but it is
unclear whether that occurs also in connection
with natural infections. CHV1 is also a part of
the kennel cough complex.
In contrast, to that in adults, for young puppies
up to 2 to 3 weeks of age, CHV1 is an acute
life-threatening disease. Puppies can become
infected in the uterus during pregnancy, or in
connection with parturition. It usually takes 6
to 10 days from when the puppies are infected
until they begin to show clinical signs. They
then usually die within 1 to 3 days. A first sign
that something is wrong with the litter is that
the puppies are restlessly moving around and
frequently vocalizing, and that they will not
suckle. Usually, all the puppies in the litter will
become infected and the mortality rate is high. If
some of the infected puppies survive, they may
later develop locomotion problems, or become
blind or deaf, because of damage to the brain,
or they may have poor kidney or liver function.
A Worldwide Magazine for the Jack Russell Terrier / Russell Terrier • Issue 2/2023 | 109
CHV1 is most commonly spread via the upper
airways, when dogs are sniffing or coughing,
or spread via saliva, urine, or vaginal
discharges, but it can also be spread when
the body for more than about 24 hours, and it
is sensitive to most disinfectants. The risk of
it spreading via clothes and shoes, therefore,
is small, although it is always a good idea to
be careful.
The canine herpes virus grows very slowly,
multiplying only once per 24 hours and is,
therefore, not very infectious. The kennel that
becomes infected with CHV1, however, can
be hit quite hard over a period of time, until
most of the dogs have become infected and
have developed antibodies against CHV1.
This may take 6 months or more, depending
on the circumstances.
When a dog or bitch is infected by CHV1 for
the first time, it will take 2 to 3 weeks before
the increase in antibodies has reached a
level that is high enough for the virus to stop
multiplying, and eventually transform into
its latent form. The CHV1 can only infect
other dogs during its actively multiplying
phase. Consequently, after 2 to 3 weeks the
individuals that have been infected by CHV1
for the first time will no longer spread the
disease to other dogs. The antibody level will
then slowly diminish over time, sometimes
over several years. If the same dog is
infected by CHV1 again this will induce a
booster effect, and this time it will take just 2
to 3 days for the antibody response to reach
the level when the virus is inactivated and
stops multiplying, and the dog no longer is
shedding the virus and, thus, will not spread
the infection to other dogs.
Consequently, only newly infected dogs spread
CHV1 to other dogs, and only during the phase
when the virus is actively multiplying, which is 2
to 3 weeks if it is the first infection or only for 2
to 3 days in a dog that has been infected before.