Infectious disease outbreak management in shelters
An infectious disease outbreak is one of the more daunting challenges in the high-risk animal shelter setting. Temporary cessation of animal intakes is a helpful initial approach to an outbreak. Appropriate vaccination of resident or incoming dogs is a crucial strategy when an infectious disease outbreak occurs in the animal shelter population. A proper vaccination strategy in the face of an outbreak is dependent on the pathogen involved, its route of transmission (oral vs. respiratory), the stage of the outbreak, effectiveness of local sanitation practices, and the vaccine formulations being used. Unfortunately, there are virtually no published data from controlled studies in dogs that address these issues, relegating decisions to clinical judgments.
Serological testing offers shelters an effective tool to help manage disease outbreaks, particularly in the case of CDV and CPV, as opposed to depopulation or prolonged lockdown of the shelter. Although additional host, pathogen, and environmental cofactors that contribute to disease outbreaks must also be taken into account during the outbreak management process, serological testing can provide supplemental insights. Serological testing, by providing individual risk assessment, can assist in population flow decision making during an outbreak. In general, healthy, seropositive dogs, especially those with high titers, are likely resistant to disease and can be considered low risk. They can be adopted with appropriate waivers. Healthy, seronegative dogs, who are potentially susceptible to disease and considered high risk, should be quarantined and separated from the rest of the population (ideally, placed in foster care outside of the shelter). They should be revaccinated, observed for development of clinical signs throughout the anticipated incubation period of the disease, and serologically retested 10–14 days later. Puppies, especially those ≤4 mo of age, require additional management during an outbreak. Serological testing and risk assessment of dogs in this age group can be misinterpreted because of the potential presence of transient maternal antibodies.
Cessation of intake into the shelter is critical for effective outbreak management. If temporary cessation of intake is not possible, then housing newly admitted dogs in a completely segregated area of the shelter (with infection control practices, including designated staff and equipment) is required to prevent disease transmission.