Description: Founded in 1904, The Journal of Infectious Diseases is the premier publication in the Western Hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases, on the microbes that cause them, and on disorders of host immune mechanisms. The CICP0 gene was transcribed as a 1.4 kb mRNA from the end of the unique long region nearby the internal repeat during early phase of productive infection of the virus. Conjunctival petechiae were detected in 22% of dogs. A correlation was found between the titers measured by the ELISA and 50% PR assay with complement, however, for field use, the ELISA is recommended as a highly sensitive test method of serodiagnosis of CHV infection adequate for dealing with a large number of samples with less demand on time and effort. These data suggest that the 47 kD glycoprotein is the common molecule of the hemagglutinin among CHV strains and the plaque-selected virus of YP11 strain appears to be a mutant whose molecular weight of the hemagglutinin changed into 41 kD. An overall seroprevalence of 14.6% was observed using SN, and 18.6% using IF. None of the submitted samples tested positive for nested PCR, and none of the sera tested CaHV-1 positive.
Adult dogs, and even those puppies more than 2 or 3 weeks old, may contract and carry the virus without suffering from any adverse symptoms. Our data indicated that CHV-1, like other herpesviruses, attached to permissive MDCK cells through two mechanisms: the first one is through the interaction mediated by heparan sulfate (HS) on the cell surface and the second involves unidentified viral component and the cellular receptor. It is when a pregnant female becomes infected that the disease is truly dangerous. Infected females may occasionally transmit the virus to her puppies in utero, leading to spontaneous abortion, or stillborn litter. More commonly however an infected mother will pass the virus to her offspring via mucoid secretions during, or after birth. Upon infection, CHV particles first attack the nasal passages, pharynx, and tonsils of young pups. During the 6 to 10 day incubation period the virus replicates and then spreads via the bloodstream to the liver, kidneys, lymphatic tissues, lungs, and central nervous system.
Once in these organs the virus proves deadly in nearly 100 percent of cases in pups less than 2 weeks of age. Clinical signs of CHV infection in young puppies include loss of appetite or disinterest in nursing, shortage of breath (dyspnea), tender abdomen, inco-ordination, soft yellow-green faeces, and possibly a bloody nasal discharge. Death occurs rapidly after onset of symptoms and many owners do not notice anything is amiss until they find a dead puppy. Diagnosis is thus often post-mortem and involves autopsy findings. While canine herpesvirus is sadly often fatal in young puppies, some puppies will manage to bypass catching the infection from an affected dam, and some will survive the condition, so you should not automatically assume that all hope is lost. Blood tests may occasionally reveal the presence of antibodies in the bloodstream, but such procedures are somewhat unreliable and not always feasible. As previously mentioned, many owners do not realize that their puppies are ill until it is too late.
For cases detected early enough however, treatment is mainly supportive and almost always futile. Keeping the puppy warm by using lamps or heat pads is the major goal of treatment, as one reason young pups are so susceptible is that their body temperature tends to be too low to kill the virus. A new vaccine is available in the UK by Merial Animal Health Ltd, best known as the makers of Frontline®. The vaccine, Eurican® Herpes 205, cannot prevent infection but if given during pregnancy it has been shown to significantly improve fertility rates and reduce early puppy death. Even bitches that already have the virus can be vaccinated. Puppies that survive a CHV infection may excrete the virus for several weeks after recovery. Isolation of sick dogs and a rigorous disinfection routine are imperative to protect other young dogs.
Since the viral particles are easily killed my most household cleaning agents, disinfection is relatively uncomplicated.