Parvovirus Outbreak in Idaho

A news report from The Olympian newspaper reports a localized outbreak of parvoviral enteritis, or “Parvo” in Southwest Idaho. According to the article, “Veterinary clinics and hospitals in Boise, Nampa and Caldwell are all reporting a spike in canines with symptoms of parvovirus. In some Treasure Valley clinics, the increase is 10 times the normal rate.”

Parvo is caused by a virus shed in the feces of infected dogs. Puppies are especially vulnerable to infection between 8 and 20 weeks of age, when the antibodies they receive from nursing gradually decline and their own immune system has not yet produced enough antibodies to be protective. Some breeds are more sensitive to the virus than others, but any puppy can become infected. And the virus is very robust, able to remain infective in the environment for months.

With a series of vaccinations, the disease can almost always be prevented. As discussed in my primer on veterinary vaccines, a series is necessary because the maternal antibodies block the vaccines, and the puppies own antibodies are produced gradually over time and take a while to reach protective levels. It is true that surviving the disease will lead to protective antibody levels, often for life. However, 20% of puppies with the disease will die, and many others will experience needless suffering.

Local vets in the area of the outbreak are theorizing that dog owners are neglecting to get all of the recommended puppy vaccine series due to the troubled economy. As the article correctly states, “The vaccine for parvovirus is very, very effective, 99.9 percent effective. It’s unfortunate to see so many cases because it does not have to happen,” said Dr. Kayla Williams of the Blayney Veterinary Clinic, which has treated 30 cases in the last four weeks.”

Outbreaks like this are unfortunate, but they provide needed reminders that vaccination is critical to prevent diseases like parvoviral enteritis, which persist at low levels in the population waiting for a lapse in vaccination to re-emerge as an epidemic. Vaccines are another medical tool that are in some ways hurt by their very success. Anti-vaccine propaganda can convince people such diseases are no longer a threat because most people who have properly vaccinated their pets will never see a case. Here is yet another piece of evidence that this is a dangerous myth.

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5 Responses to Parvovirus Outbreak in Idaho

  1. Bartimaeus says:

    I worked in an area with low vaccination rates for several years right after graduating and I don’t recall how many times I saw people or the first time with their sick puppy. I always asked about vaccination history as part of the exam, and the usual response in this situation was “We couldn’t afford the vaccinations”… Followed by a sinking feeling in my stomach and wondering how they could afford to treat the poor dog that now had parvo.
    That was before the latest wave of anti-vaccine nonsense and was usually solely for financial reasons, but just as tragic for the puppies involved.

  2. skeptvet says:


    I’m not sure what exactly you’re asking. Different vaccines do have different efficacy in terms of titer levels. The article I posted previous on vaccines has a large bilbiolography which includes a few articles looking at passthrough for different brands as examples. Are you asking specifically which current parvo vaccines are high titer?

    As for the series, of course it’s basd on population averages. We don’t know the level of maternal antibodies at various times in each individual, so we give a series which is likely to catch everybody at some point with a low-enough titer to respond to the vaccine. Boosters then become complicated. For some diseases (e.g. parvi, rabies) we have evidence that certain titer levels are predictably protective and so could substitute titers for vaccination. For other diseases, cell-mediated immunity is important and titer may or may not correlate with protection from natural challenge.

    Sorry if I’m not answering your question, I’m just not sure exactly what you’re asking.

  3. I thought you had a study that measured the 99.8% claim. I gust wanted it for my files since my info below is dated.

    From Ft Dodges literature: Vanguard 1st dose 8 wks 25% seroconversion, 2nd dose 10 wks 70%,3rd dose 12 wks 90%, Proguard 1st dose 6 wks 8%,2nd dose 9 wks 42%, 3rd dose 12 wks 100%,Ft Dodge 1st dose 6 wks 90%, 2nd dose 9 wks 100%, 3rd dose 12 weeks 100%. That is if you belive their literature. It takes about 7 days post vaccination to achieve seroconversion.The old parvo vaccines(pre 1995, contained 5×10 to the 5th(or500,000) infectious particles. The new vaccines like Ft Dodge KF11 contain 1×10 to the 11th ( 100,000,000,000 infectious paarticles ) so they are able to break through maternal antibodies at an earlier age.When Dr Schultz did his comparative study of 5 brands of vaccine in ’94,Proguard and Ft Dodge high titer vaccines proved superior so all most of the other companies changed to match in ’95.
    <<Am J Vet Res 1997 Apr;58(4):360-3
    Larson LJ ; Schultz RD
    Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison 53706, USA.

    -OBJECTIVE: To compare the ability of 6 commercially available multicomponent canine vaccines to stimulate antibody production in pups with variable amounts of maternally derived canine parvovirus (CPV) antibody and to induce protective immunity against challenge exposure.

    ANIMALS: Sixty-three 5- to 6-week-old Beagle pups with passively acquired CPV antibody titer between 1: 20 and 1:320.

    PROCEDURE: 9 pups were assigned to each of 6 vaccine groups and 1 control group. Eight pups in each group were inoculated with vaccine or saline solution twice, with 3 weeks between administrations. The ninth pup served as an uninoculated contact control. Serum samples were obtained weekly and tested for CPV antibody by hemagglutination-inhibition assay. All pups were challenge exposed with virulent CPV-2a and CPV-2b at 14 to 15 weeks of age.

    RESULTS: 3 of the vaccines failed to provide protective immunity against challenge exposure because all pups in these groups became infected and most died. A fourth vaccine protected against death, but not infection and disease. Two of the 6 vaccines induced an immune response that was protective against infection and disease.

    CONCLUSION AND CLINICAL RELEVANCE: Substantial differences existed among commercial vaccines available in 1994 in their ability to immunize pups with maternally derived CPV antibody. These differences caused many vaccinated pups to be susceptible to CPV disease for variable periods because some vaccines failed to immunize. Importantly, all 4 of the vaccines that performed poorly have recently been replaced by more effective products so that the 6 vaccines now perform similarly. (Author Abstract)

    art malernee dvm

  4. skeptvet says:

    Oh, I see. Sorry, I was just quoting the original article, so I didn’t check for references to confirm the protective figure quoted for parvovirus. Here are some references I collected when writing an earlier article of vaccination, if they are useful:

    Cooper P E, Chappius G, Saint-Gerand AL and Duret C (1991). Comparaison de l?efficacite de
    differents vaccins du chien, utilises sous forme monovalente ou associee, par evaluation des
    responses serologiques et apres epreuves virulentes 12, 22,et 26 mois apres vaccination. Bulletin
    Mensual de la Societe Veterinaires de France 75 (3), 131.

    Povey R C, Carman P S and Ewert W (1983). The Duration of Immunity to an Inactivated Adjuvanted Canine Parvovirus Vaccine. A 52 and 64 Week Postvaccination Challenge Study.
    Canadian Veterinary Journal 24, 245?248.

    Wallace BL and McMillen J K (1985). An Inactivated Canine Parvovirus Vaccine: Duration of Immunity and Effectiveness in Presence of Maternal Antibody. Canine Practice 12 (1), 14?19.

    Carmichael L E, Joubert J C and Pollock R V H (1983). A Modified Live Canine Parvovirus Vaccine. II Immune Response. Cornell Veterinarian 73, 13?29.

    Pollock R V H and Carmichael L E (1982). Maternally Derived Immunity to Canine Parvovirus Infection: Transfer, Decline, and Interference with Vaccination. Journal of the American Veterinary Medical Association 180, 37?42.

    Larson L J and Schultz R D (1997). Comparison of Selected Canine Vaccines for Their Ability to Induce Protective Immunity Against Canine Parvovirus. American Journal of Veterinary Research 58, 360?363.

    Olson P, Klingeborn B and Hedhammar A(1988). Serum Antibody Response to Canine Parvovirus, Canine Adenovirus?1, and Canine Distemper Virus in Dogs with Known Status of Immunization: Study of Dogs in Sweden. American Journal of Veterinary Research 49, 1460?1466.

    McCaw DL. Thmpson M. Tate D. et al. Serum distemper and parvovirus antibody titers among dogs brought to a veterinary hospital for revaccination. JAVMA 1998;213:72-75

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