Canine herpesvirus (CHV)
Canine herpesvirus (CHV) is an alphaherpesvirus affecting dogs worldwide, and is a well-known agent of lethal neonatal canine infections and the fading puppy syndrome. The virus is very common and it has been found all over the world. The prevalence of the infected dogs depends on the region, from 20% to 98% of the infected dog rate. Conducted studies have shown following geographical seroprevalence of CHV: 88% in England, 80% in Norway, 45.8% in Belgium, 39.3% in the Netherlands ad 39.3% in Turkey. Because virus can change into latent stage, infected animals, which are still contagious, may show seronegative status, due to which any seroprevalence study shows underestimated infection rates. The virus is not contagious for humans.
CHV is composed of an enveloped viral DNA which is sensitive to UV light, high temperatures and lipid solvents, such as ether or chloroform, and most of disinfectants. This makes the virus unstable outside of the host organism, so for the transmission a close contact is required. CHV lives in the reproductive and respiratory tract of the infected dog. Transmission is mediated through oral, nasal, or seminal or vaginal fluids of the infected dog, of which oronasal transmission is considered as the main route of infection. A stud can transmit the virus to the bitch, or vice versa. Puppies usually get infected through contact with the birth canal or from nasal and oral fluids of the mother.
Symptoms associated to CHV infection in puppies include:
- Sudden death of new-born puppy
- Weakness, depressed attitude
- Persistent crying
- Lack of appetite
- Discomfort in the abdomen
- Soft, yellow-green feces
- Cold puppies
- Respiratory difficulties, nasal discharge
- Hemorrhages, such as nose bleeds and small bruises
- Older puppies may develop nervous system abnormalities, including blindness and seizures
In adult dogs, herpes virus infections include:
- Often there are no symptoms visible
- Respiratory and ocular infections
- Reproductive problems
Unfortunately, there is no available cure for canine herpesvirus, and the treatment is limited to management of the symptoms. In affected puppies the survival prognosis is poor even with given treatment. It is recommended to keep infected puppies warm, due to viral sensitivity to temperature.
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Ronsse, V., Verstegen, J., Thiry, E., Onclin, K., Aeberlé, C., Brunet, S., & Poulet, H. (2005). Canine herpesvirus-1 (CHV-1): clinical, serological and virological patterns in breeding colonies. Theriogenology, 64(1), 61–74.
Papageorgiou KV, Suárez NM, Wilkie GS, McDonald M, Graham EM, Davison AJ (2016) Genome Sequence of Canine Herpesvirus. PLoS ONE 11(5): e0156015. https://doi.org/10.1371/journal.pone.0156015
Ledbetter, E. C. (2013). Canine herpesvirus-1 ocular diseases of mature dogs. New Zealand Veterinary Journal, 61(4), 193–201. doi:10.1080/00480169.2013.768151