Much like children in schools or childcare centers, animals in shelters are at higher risk for spreading and acquiring infectious diseases. In certain circumstances, these diseases can also spread to the people caring for and interacting with shelter animals. However, this risk can be significantly reduced through strategies to prevent disease spread.
How is Disease Spread?
Infectious diseases can be spread through a variety of methods. This chart details the primary methods of transmission concerns in an animal shelter, as well as common infectious diseases in cats and dogs that are spread via that method.
Mode of Transmission
The infectious agent is suspended and can travel a distance through the air
Canine infectious respiratory disease (CIRDC)
Small infectious droplets travel a short distance after being expelled but are not
suspended in the air
Feline upper respiratory infections (URI)
The infectious agent is spread via body surface to body surface contact between
animals or animal to human
Most infectious diseases in the shelter
A contaminated item, surface, piece of clothing, or hand spreads disease between animals
CIRDC, URI, ringworm, canine parvovirus, and feline panleukopenia virus amongst others (particularly common with pathogens that are hardy in the
Disease is spread via another living organism
The infectious agent is sexually transmitted or, more commonly, spread directly
from mother to offspring
Feline leukemia virus Canine brucellosis
Who Will Get Sick?
Numerous factors influence whether infectious disease will spread in the shelter and whether an individual animal will become ill after exposure. It is essential to understand these risk factors as an effective infection control strategy takes a multimodal approach and addresses each one.
There are inherent characteristics of infectious agents that impact their ability to cause disease and their likelihood of spread. Some pathogens, such as canine parvovirus, feline panleukopenia virus, and ringworm, are very hardy in the environment. Many common pathogens are easily spread, such as CIRDC pathogens, which can be spread via aerosolization. The dose of an infectious agent will also impact the likelihood of spread and disease. For example, a puppy shedding large amounts of canine parvovirus in his stool will be more likely to spread the disease than one only shedding trace amounts.
Aspects of the host (the animal exposed to the infectious agent) are another component that impacts the likelihood of developing disease. Very young, geriatric, or immunocompromised hosts are more likely to develop disease when exposed to a pathogen. Stress can negatively impact the immune response and make an animal more likely to develop infectious disease. Conversely, vaccination and other preventative wellness care, such as deworming, will boost the host’s ability to combat disease.
The environment surrounding a potential host can either facilitate or hinder the spread of disease. Physical barriers such as separate rooms or personal protective equipment (PPE) can reduce disease spread when used properly. Effective sanitation, including hand washing or sanitizing, is also an important tool to prevent environmental spread of disease.
Overcrowding can increase the risk of disease through all three categories: increasing the dose of infectious agents, causing stress for potential hosts, and overstretching environmental control measures. Successful population management is a vital tool for reducing the spread of disease in animal shelters.
What Strategies Help Prevent the Spread of Disease?
Reduce the likelihood of a contaminated environment through sanitation, prompt identification of
sick animals, isolation, and operating within the shelter’s capacity.
Identify clinical signs of disease at intake.
Boost the ability of the individual animal to avoid disease through intake vaccinations, parasite treatment, reduction of stress, and minimizing their length of stay in the shelter.
Avoid contributing to the spread of disease through frequent hand washing or sanitizing, careful use of PPE, changing contaminated clothing, and following the order contagion.
When Do Animals Need to be Isolated or Quarantined?
Isolation = separating sick animals while they are at risk of transmitting disease to other animals or people. Animals are isolated for the duration of the shedding period, or the amount of time that sick animals are expected to shed the infectious organism.
Quarantine = separating animals who have been exposed to infectious disease to monitor them for signs of illness. Animals are quarantined for the duration of the incubation period or the length of time between exposure and signs of disease.
Shedding period and incubation period will vary for each disease. Quarantine of animals without known (or highly suspected) disease exposure is not recommended. Unnecessary quarantines prolong length of stay, contributing to overcrowding, stress, and disease exposure.