Puppies need protection against canine distemper virus and canine parvovirus as these diseases have the greatest impact on this age group.
Canine Distemper Virus
Canine distemper virus (CDV) is a multisystemic viral disease of dogs that affects puppies most commonly aged between 3 and 6 months.
Although considered a disease of domestic dogs, many other canids are equally susceptible, as well as mustelids, large cats and marine mammals.
CDV is an enveloped RNA virus which is highly susceptible to environmental and chemical inactivation. It is highly contagious and transmitted through droplets and aerosol transmission involving close contact with infected dogs.
The clinical signs of distemper in dogs vary dramatically and are highly dependent on virus strain and the age and immune status of the host, as well as concurrent infections with other viruses and bacteria. Many dogs experience subclinical infection, whereas others experience rapidly progressive infection followed by death. The incubation period ranges from 3 to 6 days1.
These can be varied and include multiple organs. Commonly, pyrexia, lethargy and anorexia are seen as well as signs specific to the organs affected:
- Respiratory: nasal and ocular discharges, cough, tachypnea, pneumonia
- Gastrointestinal: vomiting, diarrhoea, dehydration
- Dermatological: pustular dermatitis, digital and planum hyperkeratosis (hard pad)
- Ocular: conjunctivitis, sudden blindness, keratoconjunctivitis sicca, corneal ulcers
- Neurological: seizures, twitching
(Photographs by Craig Greene © 2004 University of Georgia Research Foundation Inc.)
Nasal and digital hyperkeratosis in dog with systemic distemper
(Photos courtesy of Dr Hal Thompson, Glasgow University)
Dog with systemic distemper showing ocular and nasal discharges.
Although vaccination has reduced the incidence of the disease, distemper still remains important where large numbers of young dogs with inadequate immunity are housed together, such as in kennels, large breeding facilities, and shelter environments1.
Canine parvovirus is a highly contagious virus resulting in severe gastrointestinal disease that can be fatal. It is a DNA virus which is non-enveloped, making it extremely resistant to desiccation and allowing it to be stable and remain in the environment for up to 5-7 months, and for up to a year in contaminated soil.
Canine parvovirus is believed to have originated from feline panleukopenia virus (FPV). The most likely scenario is that a mutation of the FPV virus adapted to a new dog host via non-domestic carnivores, such as mink or foxes. Soon after its first recognition in the late 1970s, the original virus type CPV-2 was replaced by new antigenic virus types CPV-2a, CPV-2b and, most recently, CPV-2c. All of these virus types, except the original CPV-2, exist today in the dog population.
It is highly contagious and is readily transmitted from one dog to another through contact with infected faeces. This includes transmission via clothing, surfaces, soil and any environment that has been contaminated with infected faeces.
One gram of faeces from an infected, virus-shedding dog is thought to contain enough viral material to infect over 10 million susceptible dogs by oral exposure!2
Incubation of parvovirus is, on average, three to seven days3, although modern strains tend to replicate more rapidly and can have a shorter incubation of around 2-5 days. Gastrointestinal clinical signs usually appear over the subsequent two to three days. Faecal shedding occurs from four to six days to several weeks following infection4.
Canine parvovirus replicates in dividing cells, and particularly impacts tissues and organs with rapidly dividing cells such as the intestinal crypt cells within the gut, the lymphoid tissues including those of the thymus and bone marrow. Diarrhoea and vomiting are the result of parvovirus infection destroying the intestinal cells, compromising the integrity of the intestinal barrier, and similarly cells within lymphoid tissues are also destroyed resulting in a profound leukopaenia, and associated immune suppression.
These typically include:
- Profuse and often haemorrhagic diarrhoea
- Abdominal discomfort
- Cardiovascular shock
Canine parvovirus vaccination is typically very effective in preventing disease. However, uncommonly puppies may still be at risk of contracting the disease despite vaccination. Of a range of factors that can impact immunity, by far the most likely is due to high levels of maternally-derived antibodies persisting to an age where it may interfere with the primary immune response. Puppies can also be incubating the virus at the time of vaccination and come down with disease before the vaccine’s onset of immunity.
1. Sykes JE (2014). Chapter 15: Canine Distemper Virus Infection. pp152-165. Sykes, JE (Ed). Canine and Feline Infectious Diseases. WB Saunders. pp152-165.
2. Humm KR & Hughes D (2009). Chapter 112 – Canine Parvovirus Infection. In: Small Animal Critical Care Medicine. Eds: Silverstein DC & Hopper K. WB Saunders, p 482-485.
3. Caddy S (2017). Acute infectious gastroenteritis in UK dogs. Part 1: viruses, bacteria and parasites, VetCPD 4(1): 19-22.
4. Freisl M, Speck S, Truyen U et al (2017). Faecal shedding of canine parvovirus after modified-live vaccination in healthy adult dogs, Vet J 219: 15-21.
Nobivac® DP PLUS is a vaccine containing live attenuated canine distemper virus and live recombinant canine parvovirus. POM-V.
Further information is available from the SPC, Datasheet or package leaflet. MSD Animal Health UK Limited. Registered office Walton Manor, Walton, Milton Keynes MK7 7A J, UK. Registered in England & Wales no. 946942.
Advice should be sought from the medicine prescriber.
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