Quarantine: traditional disease control still one of the best

Four giant pandas recently journeyed from Toronto to Calgary to join the Calgary Zoo collection. But these bamboo-eating bears will be restricted from public visits until May.

During this period, the pandas will get acquainted with their new surroundings and caretakers. It also functions as a type of quarantine to allow caretakers and veterinary staff to monitor them for signs of illness. Although the pandas are at a low risk of illness, quarantine is an important tool to control the spread of infectious agents between animals.

Quarantine refers to a time period of isolation for animals and people to reduce the spread of infectious diseases. It is one of the oldest ways to control contagious diseases and can be quite effective.

Beyond its usefulness to zoos, quarantine is an important pillar of disease control for a variety of animal diseases.

Historically, quarantine in Canada has been used to detect and exclude a number of economically important cattle diseases, including pleuropneumonia and foot-and-mouth disease.

Quarantine generally consists of separating the newly arrived individuals so there are no opportunities for pathogens spread by direct contact or potential for airborne pathogens to spread.

In livestock settings, this means no shared fence lines and avoiding nose-to-nose contact. The quarantined animals should have separate equipment that is used only for their care.

People should change into dedicated clothing and boots for handling the quarantined animals.

Objects like troughs, feeders and shovels could harbour infectious agents while contaminated clothing and boots can also spread pathogens. These objects need to be thoroughly cleaned and disinfected if they must be transferred between groups.

It is also important to work from clean to dirty areas of the farm. This means feeding and working with the resident animals first, and saving the chores in quarantined newcomers’ area for last.

Fever is one of the first signs of infection in animals, so many quarantine protocols require daily or twice-daily temperature monitoring. This is particularly common for horses.

For quarantine to be effective, animals need to be segregated for the disease incubation period, which is the time between when an animal is infected and when it starts to show outward signs of disease.

The incubation period of bovine respiratory syncytial virus is between two and five days. This virus is an important cause of pneumonia in calves and newly arrived feedlot cattle and leaves them prone to serious secondary bacterial infections. Calves being introduced to a herd without this disease would need to be isolated for a week or so to catch signs of infection. After the incubation period, animals have a lower probability of introducing the pathogen into the herd. If the incubation period is too short, infected animals may go undetected and be mistakenly released into the herd.

The use of quarantine is also important for animals that periodically leave the farm and then return, such as horses that attend competitions and cattle that go to shows and community pastures. These traveling individuals could pick up infections while away and may be particularly prone to infectious diseases due to the stress of transport.

Once back on the farm, it is a good idea to segregate these individuals for a period of time to ensure they are healthy.

For horses, quarantine after travel is important to control diseases like equine influenza and strangles.

Although modern medical advances have given us other tools such as vaccinations and diagnostic tests to combat infectious diseases, the old principle of quarantine still has its place on modern farms. And, apparently, with pandas in zoos.

Dr. Jamie Rothenburger is a veterinarian who practices pathology and is an assistant professor at the University of Calgary’s Faculty of Veterinary Medicine.
Twitter: @JRothenburger

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