People concerned about the ebola quarantines of health workers returning from Africa might be interested in how quarantines issued during animal disease outbreaks have helped save lives.
In 2006, while I was the N.J. State Veterinarian, two seemingly healthy asymptomatic horses were transported to Monmouth Park, a racetrack in New Jersey, from Canada.
No one knew at the time of transportation that Equine Herpes Virus had infected horses at the original farm. As I said in a press release in 2006, “[t]he EHV-1 organism spreads quickly from horse to horse and can cause respiratory problems especially in young horses, spontaneous abortions in pregnant mares, and the neurologic form of the virus can reach high morbidity and mortality rates.” It usually has an incubation period of 2-10 days. EHV outbreaks at horse shows and racetracks have been devastating, and morbility and mortality rates are often high.
“Clinical signs of respiratory disease include fever, serous nasal discharge, depression, pharyngitis, cough, inappetence, and/or submandibular or retropharyngeal lymphadenopathy. In horses infected with the neurologic strain of EHV-1, clinical signs include, mild incoordination, posterior weakness/paralysis and recumbency, loss of bladder and tail function, and loss of sensation to the skin in the perineal and inguinal areas. In exceptional cases, the paralysis may progress to quadriplegia and death. Prognosis depends on severity of signs and the period of recumbency.”
The horses imported from Canada developed fevers, and one was successfully treated—the other was unfortunately euthanized.
Once we learned of the outbreak in Canada, a quarantine was issued, different levels of risk were identified, horses were co-housed according to their level of risk, all known contact horses were isolated, temperatures were taken twice daily, horses were tested for virus, and strict biosecurity measures were implemented.
The horses at Monmouth Park were quarantined for several months.
Horses grouped together had to test negative 21 days after the last clinical signs of infection or the last positive test result from the group. It was impossible to isolate every horse individually. In some cases set backs occurred, when one horse in a barn tested positive during the waiting period, effectively resetting the isolation clock for all co-housed horses. The 21-day waiting period was intentionally conservative, but considered essential to stop the spread of this deadly equine disease.
It worked. The quarantine was eventually lifted, and unlike other EHV outbreaks with high mortality rates, only the first infected horse died.
Notably, EHV spreads much more easily than the ebola virus. It can be spread airborne over a distance of up to 35 feet.
Still, perhaps there is a lesson to be learned here. It is much easier to isolate people, than a group of show or race horses.
Until there is a better understanding of how medical care givers become infected with ebola, a 21-day isolation period for those exposed to ebola-infected people seems reasonable, albeit inconvenient.
It is not a punishment, nor should it diminish the humanitarian efforts of those willing to help at ground zero of this globally important outbreak.
They should be saluted for their noble and critical efforts to change the course of an outbreak of a highly contagious and deadly disease.