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Recent Advances in Canine Infectious Diseases, Carmichael L. (Ed.)
International Veterinary Information Service, Ithaca NY (www.ivis.org), 2004; A0102.0899
Neonatal Viral Infections of Pups: Canine Herpesvirus and Minute Virus of Canines Canine Parvovirus-1 (Last Updated: 19-Aug-2004 )
L. Carmichael
Recent Advances in Canine Infectious Diseases, Carmichael L. (Ed.)
International Veterinary Information Service, Ithaca NY (www.ivis.org), 2004; A0102.0899
Neonatal Viral Infections of Pups: Canine Herpesvirus and Minute Virus of Canines Canine Parvovirus-1 (Last Updated: 19-Aug-2004 )
L. Carmichael
Canine Herpes VirusExperience has taught many breeders who had accepted neonatal pup death rates of 15 - 25% that simple management could greatly reduce mortality. Examination of bitches for general and reproductive health before and after whelping, supplemental or tube feeding of pups that fail to suckle and providing warmth, which is vital to pups during the first 2 weeks of life since temperature regulation is poor are important factors. Supplemental radiant heat to raise the environmental temperature to ~85ºF, and a relative humidity of ~60% during the first week of life, especially if pups are orphaned, has reduced mortality rates in several kennels from ~25% to <10%. More than 75% of pup deaths occur prior to the 3d week of life, the vast majority occurring during the first week due to physiologic, congenital/genetic, behavioral bitch, environmental conditions or bacterial septicemias. Unfortunately, there is a discouraging lack of knowledge of the true causes of most neonatal illnesses or death and little research is being done on this important subject.
Infectious diseases are believed to comprise only a very small portion of pup deaths up to the time of weaning; however, two viral infections have been described that affect pups during the first 2 - 5 weeks of life: Canine herpesvirus is widely recognized; minute virus of canines CPV-1 has only recently been recognized as a pathogen. Canine adenovirus-1, distemper and canine coronavirus, as well as several bacterial infections, also may cause puppy deaths.
Minute Virus of Canines (Canine Parvovirus-1)Disease caused by CHV is generally fatal in neonatal pups who lack immunity derived from their dams. Neonatal pups may be infected during passage through an infected dam's birth canal or, more commonly, by contact with oronasal secretions of the dam or other dogs in a kennel. Infected littermates, or neighboring dogs who are shedding virus, also serve as sources of infection. Deaths of 1 to 4 week old pups are most common. Pups rarely die if they are 2 - 3 weeks old at the time of exposure. The duration of illness in newborn pups is 1 to 3 days. Signs consist of anorexia, dyspnea, pain upon abdominal palpation, incoordination and, often, soft, yellow-green feces. There may be a serous, or hemorrhagic nasal discharge. Petechia are common on the mucous membranes. Rectal temperatures are not elevated. Thrombocytopenia has been reported in dying pups...
Vaccines
An inactivated, subunit vaccine (Eurican Herpes 205, Merial Animal Health) has been available in Europe since 2003. The vaccine is specifically indicated for bitches during pregnancy. It consists of purified CHV glycoproteins in a mineral oil solvent. It has been shown to have few undesirable effects; nevertheless, transient edema may occur at the injection sites. Reactions usually regress within 1 week. Eurican Herpes 205 was shown to provide good immunity to newborn pups after 2 injections had been administered to their dams. Vaccine should be given to dams during heat or early pregnancy and, again, 1 to 2 weeks before the expected date of whelping...
Treatment
Antiviral drugs have been generally unsuccessful, although some success has been reported with pups in exposed litters given vidarabine before the onset of symptoms. Antiviral treatment may spare life, but residual damage to the CNS and heart may occur. There has been success in preventing infection in neonatal puppies prior to exposure to CHV during kennel outbreaks by injecting 1 - 2 ml of immune sera from affected dams. Such treatment is effective only if virus has not generalized. Once illness develops in pups, serum treatment is ineffective. Immune serum is not available commercially.
[ August 20, 2004, 03:09 PM: Message edited by: Betsy Iole ]Most cases have been pups at necropsy who died suddenly between 1 and 3 weeks of age with respiratory distress and/or variably severe diarrhea. In litters where dead pups were observed, littermates that survived had vague signs, e.g., anorexia, failure to nurse or eat and mild respiratory illness or diarrhea. Such pups recovered within a few days. Transplacental infections with fetal deaths and abortion have been demonstrated experimentally; therefore, CPV-1 may be a cause of abortions or "failures to conceive". The natural route of infection is believed to be by oral exposure, as with the more pathogenic canine parvovirus type 2...
The principal clinical signs reported are those of "fading pups" - lethargy, loose stools or diarrhea, respiratory distress (dyspnoea), and sudden death in newborn pups attributed to viral myocarditis.