Page 951 - Cote clinical veterinary advisor dogs and cats 4th

Herpesvirus, Dog 467

• The optimal temperature for CHV replication • PCR can also be done on the aforementioned • Dams that abort or have a naive litter that
is 33°C-35°C (i.e., temperature of the outer selected tissues but is usually reserved for subsequently becomes infected by a second-
VetBooks.ir is the normal body temperature range for TREATMENT and subsequently have normal litters. CHV Diseases and Disorders
ary source of CHV commonly seroconvert
determining latency.
genital and upper respiratory tracts). This
puppies < 3 weeks of age (poikilothermic),
passive immunity is passed to offspring
which increases the susceptibility to severe,
systemic CHV disease in this age group. Treatment Overview through colostrum. Colostral immunity,
which persists to 8 weeks, prevents clinical
Treatment of CHV-induced neonatal disease signs in the puppies but does not prevent
DIAGNOSIS requires rapid response on the part of owner primary infection and subsequent latency.
and veterinarian. Usually by the time clinical • Ocular disease can be self-limited or resolve
Diagnostic Overview signs occur, individually affected pups have a after treatment with antivirals. Respiratory
Although a presumptive diagnosis of CHV- poor prognosis. Unaffected littermates may disease in adults has a good prognosis with
induced disease can be achieved by the observa- be treated with antiviral drugs and/or CHV- supportive care.
tion of ill pups < 3 weeks of age, confirmation hyperimmune serum. The temperature of the
of CHV can be obtained histopathologically on puppy environment should be increased. PEARLS & CONSIDERATIONS
fixed liver and kidney tissue of affected pups,
virus isolation from fresh/frozen tissues, and/ Acute General Treatment Comments
or polymerase chain reaction (PCR) assay of • Treatment of neonatal puppies with CHV- CHV is a manageable infection and a pre-
whole blood from pups. Carrier dogs can be induced disease is usually not recommended ventable disease (see Prevention and Client
identified by PCR testing of whole blood from because of rapid progression, poor prognosis, Education below).
adult dogs. Ocular swabs may be submitted for and the potential for cerebellar and retinal
virus isolation or PCR testing. dysplasias in surviving puppies. Prevention
• If only a portion of the litter demonstrates • Good hygiene: cleanliness of dam, rigorous
Differential Diagnosis overt signs, the remaining littermates can handwashing or use of gloves by handlers
• Acute-onset respiratory signs/respiratory dis- be treated with immune serum (2 mL of • Puppy environment with an ambient tem-
tress of upper and lower airway passages: canine serum from a dog with known anti-CHV perature that minimizes CHV replication
adenovirus type 2; canine parainfluenza; canine titer, given intraperitoneally). (>35°C)
influenza (H3N8, H3N2); canine respiratory • Neonates should be maintained in an • No vaccine is available in the United States.
coronavirus; Bordetella bronchiseptica; upper- environment with high humidity (up to A European product has been licensed, with
lower airway foreign body 55%) and elevated ambient temperatures of good results reported when used before
• Reproductive disease: Brucella canis, 36.6°C-37.7°C (98°F-100°F), given CHV’s breeding.
Streptococcus spp; canine distemper virus; sensitivity to higher temperatures. Caution
neosporosis; toxoplasmosis and constant rectal temperature monitoring Technician Tips
• Ocular disease: primary bacterial infection, are essential to avoid iatrogenic hyperthermia. • Emphasize good prenatal and postnatal
foreign body • Ocular disease: prevention of secondary hygiene and biosecurity with clients.
bacterial infection (topical ocular antimi- • Incorporate kennel surveillance program for
Initial Database crobials), treatment for comfort (topical B. canis and CHV testing before breeding
CBC, serum biochemistry profile, urinalysis: ocular atropine), antiviral therapy (0.1% and arrival at kennel.
values are usually nonspecific, but a marked idoxuridine, 1% trifluridine, or cidofovir • Identify first-time pregnant dogs as high risk
thrombocytopenia may be observed. A marked 0.5% ophthalmic solution) and quarantine from outside dogs/humans
increase in the alanine aminotransferase activity • Treatment of adult dogs with respiratory as much as possible.
may be found in affected neonatal puppies. signs as for CIRDC • Advise clients that CHV disease (respiratory/
Be aware that many laboratory values differ ocular) can occur in older dogs of either sex.
in neonatal and adult dogs. Chronic Treatment
Due to high incidence of life-threatening Client Education
Advanced or Confirmatory Testing sequelae, treatment is not recommended if • Planned exposure of young (>6 months)
Antemortem testing: pup is presented already showing clinical signs. puppies to older dogs to naturally immunize
• Serologic titers from affected adult dogs them before breeding and whelping. This
(titers ≥ 1 : 2 indicate exposure/infection). Behavior/Exercise induced infection rarely becomes clinically
Antibody titers do not correlate with active Puppies will be in pain and crying. Keep as overt, but if it does as a respiratory disease,
viral shedding but are good indicators of comfortable as possible. a 2-week quarantine is advised.
prior infection and latency status. • Maintenance of a strict quarantine period
• Virus isolation from nasal/ocular/urogenital Possible Complications to work within the 6-week danger period (3
swabs indicates infection and active shedding. Treatment of clinically ill puppies may result weeks before and 3 weeks after whelping).
• PCR of ocular swabs or whole blood indicates in cerebellar and retinal dysplasias. • Maintain temperature > 35°C because CHV
infection and active viremia or latency. replication is very heat sensitive.
Postmortem testing (aborted/neonatal dead Recommended Monitoring • Be familiar with early signs of ocular disease,
puppies): Puppies presented while showing clinical signs especially blepharitis and conjunctivitis, and
• Virus isolation from lung, bronchiolar lymph should be monitored every few hours because seek immediate veterinary care.
nodes, liver, kidney, and spleen the prognosis is poor. Dam can be monitored
• Histopathologic evaluation of lung, liver, by checking CHV antibody titers and by PCR SUGGESTED READING
kidney, spleen, small intestine, and brain. testing of urogenital secretions (swabs). Evermann JF, et al: Canine reproductive, respiratory,
Depending on the stage of cellular infec- and ocular diseases due to canine herpesvirus. Vet
tion and method of fixation, basophilic or PROGNOSIS & OUTCOME Clin North Am Small Anim Pract 41:1097-1120,
acidophilic intranuclear inclusions may be 2011.
noted. The intranuclear inclusion bodies are • Prognosis for clinically ill neonates is poor; AUTHOR: James F. Evermann, MS, PhD
considered pathognomonic for CHV. euthanasia should be considered. EDITOR: Michelle A. Kutzler, DVM, PhD, DACT
• No CHV immunohistochemical test is • Unaffected neonatal puppies from an affected
commercially available. litter have a good prognosis with proper care.
www.ExpertConsult.com