Canine Distemper Protocol

 

Canine Distemper Protocol

 

Date Written: Yann Sokchea, BSc in lab science, MSc, DVM.

Author/Approved by:

Date Revised:

Date Implemented: 19 May 2025

 

Purpose: The purpose of this document is to guide treatment and testing for distemper in dogs.

 

Background:

Distemper is a viral infection that typically causes some or all of the following signs in most cases: upper respiratory, lower respiratory, gastrointestinal, or neurological; however, it can infect any organ system of dogs and subsequently cause a wide variety of signs (including skin lesions, urinary tract/kidney involvement, and transplacental infection). It is commonly spread through aerosolization of respiratory secretions, though it is also shed in other bodily fluids. Survival in adult dogs can be greater than 90% with aggressive treatment, but mortality in puppies often approaches 50% or more. It poses a challenge in shelter settings because of the potential for extended periods of shedding even after clinical recovery (weeks to months); during this period, dogs are still considered contagious.

Routine vaccination is effective and is recommended as a core vaccine for owned and shelter dogs. Despite this, however, many dogs entering shelters are not protected; previous studies report that 57% to 62% of dogs do not have a protective antibody titer to CDV upon entering shelters. Current shelter guidelines recommend vaccination upon intake, and though some protection is gained rapidly and can prevent mortality, protective antibody titers to prevent infection take several days.

Testing using a CDV PCR test has the potential to be complicated due to the fact that modified live vaccines may cause a positive PCR result, and a cut-off value is given on test results; however, low viral counts (below the cutoff) also occur with early or late infection. If clinical signs are present or if dogs come from a high-risk situation, every positive result should be treated as real infection until proven otherwise.

 

Treatment:

 

Treatment for canine distemper is supportive; there is no direct treatment for the viral component of the disease. Treatment is aimed at controlling clinical signs and supporting the dog through the illness.

 

·        Mild upper respiratory signs

o   This includes any dog showing only mild respiratory signs, including ocular discharge, nasal discharge, sneezing, or cough, but is otherwise BAR and eating/drinking.

o   Doxycycline 10mg/kg SID x 10 days

o   Topical antibiotic medications can be used for ocular signs (BNP, tobramycin, etc.)

 

·        Systemic signs

o   This includes dogs that develop a fever either while on doxycycline or have a fever that does not respond in 24 hours to doxycycline treatment

o   This can also include dogs with upper respiratory signs that then progresses to include gastrointestinal signs (inappetance, vomiting, diarrhea)

o   Additional treatments:

§  Subcutaneous fluids (120ml/kg/day divided BID to TID) or IV fluids (boluses or continuous) to maintain hydration.

§  Anti-emetics/gastrointestinal protection for patients not eating or vomiting

·        Maropitant (Cerenia) 1mg/kg PO, SQ, or IV SID


·        Ondansetron (Zofran) 0.5 - 1mg/kg IV or SQ BID OR Dolasetron (Anzemet) 0.5mg/kg IV or SQ SID

·        Famotidine 1mg/kg IV, SQ, or PO BID OR Omeprazole 1mg/kg PO BID OR pantoprazole 1mg/kg IV SID

 

·        Lower respiratory signs

o   This includes dogs with moderate to severe tachypnea or dyspnea, likely related to CDV pneumonia.

o   Oxygen therapy should be considered for patients with severe lower respiratory signs (via nasal canula or oxygen cage); if this is not available in-house, transfer to a critical care facility or consider humane euthanasia.

o   Consider dexamethasone SP 0.1-0.2mg/kg IM or IV (anti-inflammatory dose), particularly if heartworm positive, followed by tapering dose of prednisone when appetite returns.

o   Clavamox 12.5mg/kg PO BID or ampicillin 22mg/kg SQ or IV BID to TID and Enrofloxacin 10mg/kg PO, IM, or IV for broader spectrum coverage (for pneumonia)

o   Nebulization with saline and coupage BID to TID

 

       Neurological signs

       For active seizure activity: Diazepam 5-10mg/kg IV, intranasal, or rectally

       For longer-acting control:

       Phenobarbital 10-20 mg/kg IV once to effect then 2-8 mg/kg PO q 12 hrs

       and/or levetiracetam (60mg/kg IV bolus, then 20-30mg/kg PO or IV q8h or equivalent for BID extended release tablets)

       For tremors:

       Methocarbamol 55-220mg/kg IV initially, do not exceed 330mg/kg/day; can also be used in a CRI

       Methocarbamol 330mg/kg PO divided BID for ongoing control

       Refractory and severe neurological signs causing significant reduction in quality of life warrant the consideration of euthanasia. Mild signs may not impact quality of life, but they may or may not resolve with recovery – some dogs have permanent mild neurological signs (typically tremors) but live normal lives. Mild neurological signs alone do not warrant euthanasia.

 

Isolation and Management:

 

·        Dogs with any respiratory signs should be isolated from general population.

·        PPE in the isolation area consists of: gloves, gown or coveralls (coveralls preferred), shoe covers.

·        PPE should be changed in between individual patients or litters housed together to prevent spread of other illness.

·        Dogs in isolation should be cared for by either separate staff or last in the order of animals cared for separate staff is not possible to prevent spread of distemper to the healthy population.


·        During recovery, distemper dogs may be housed with fully vaccinated (at least two vaccines including one as an adult dog within the last 3 years), otherwise healthy adult dogs (over one year of age, no immunocompromising conditions or medications, no significant chronic health issues). See Canine Distemper Virus for Fosters document.

 

Exposure and Quarantine

 

·        Dogs that are exposed to a distemper positive dog should be evaluated and handled based on risk.

·        Puppies (< 6 months of age) are considered high risk, regardless of vaccine status.

·        Adult, healthy dogs are considered fully vaccinated and low risk if:

o   Dogs recently entering a shelter are older than 6 months and have received an intake vaccine AND a booster vaccine two weeks (or more) after the initial vaccine.

o   Dogs have been in a home or at the sanctuary for an extended period and are considered current on their DHPP vaccine through a booster within the last year (or within the last 3 years for 3 year labeled vaccines).

o   Low risk dogs that have been exposed should be monitored for any clinical signs but do not need to be quarantined.

·        Antibody titer testing may be used at the discretion of the veterinarian for adult dogs only.

o   If greater than a week since exposure, titer testing cannot distinguish between antibodies induced due to active infection and vaccine-induced (or induced from prior exposure).

o   Paired antibody and PCR testing may be used to eliminate the need for quarantine in exposed, adult dogs. A protective titer and concurrent negative PCR test may replace quarantine.

o   Antibody titer testing does not yield predictable results in puppies due to inability to distinguish between transient maternal antibodies and long-lasting vaccine-inducted antibody protection.

·        High risk dogs that have been exposed to a positive dog should be quarantined for 14 days after the exposure.

o   If at any point, they develop clinical signs consistent with distemper, they should be tested at that time.

o   If no clinical signs develop, at the end of 14 days, they should be tested (CDV only PCR test).

o   If negative, they may be cleared from quarantine.

o   If positive, move to isolation and follow the serial testing protocol outlined above.

 

References:


American Animal Hospital Association. (2017). Vaccination Recommendations Shelter- Housed Dogs. Retrieved from https://www.aaha.org/guidelines/canine_vaccination_guidelines/shelter_vaccination.aspx

 

Association of Shelter Veterinarians. (2010). Guidelines for standards of care for animal shelters. Retrieved from https://www.sheltervet.org/assets/docs/shelter-standards-oct2011- wforward.pdf

Crawford, C. 2014. Everything Shelters Need to Know About Canine Distemper. https://www.maddiesfund.org/everything-shelters-need-to-know-about-canine-distemper.htm

 

Crawford, C. 2017. Personal communication. Unpublished data on distemper shedding in shelter dogs.

 

Edinboro, C. H., Ward, M. P., & Glickman, L. T. (2004). A placebo-controlled trial of two intranasal vaccines to prevent tracheobronchitis (kennel cough) in dogs entering a humane shelter. Preventive Veterinary Medicine,62, 89-99. doi:10.1016/j.prevetmed.2005.03.001

Greene, C. E. (2012). Canine Distemper. In Infectious diseases of the dog and cat(pp. 25-41). St. Louis, MO: Saunders Elsevier.

 

Larson, L. J., & Schultz, R. D. (2006). Effect of vaccination with recombinant canine distemper virus vaccine immediately before exposure under shelter-like conditions. Veterinary Therapeutics,7(2), 113-118.

Lechner, E. S., Crawford, P. C., Levy, J. K., Edinboro, C. H., Dubovi, E. J., & Caligiuri, R. (2010). Prevalence of protective antibody titers for canine distemper virus and canine parvovirus in dogs entering a Florida animal shelter. Journal of the American Veterinary Medical Association,236(12), 1317-1321. doi:10.2460/javma.236.12.1317

 

Leutenegger, C., Crawford, C., Levy, J., & Estrada, M. (2011). Canine Distemper Virus Quantification by Real-time PCR Allows to Differentiate Vaccine Virus Interference and Wild- type Infection. ACVIM Forum 2011.

 

Litster, A., Nichols, J., & Volpe, A. (2012). Prevalence of positive antibody test results for canine parvovirus (CPV) and canine distemper virus (CDV) and response to modified live vaccination against CPV and CDV in dogs entering animal shelters. Veterinary Microbiology,157(1-2), 86-

90. doi:10.1016/j.vetmic.2011.12.030

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