Disease outbreaks in any herd of animals can be a challenge. In the West, two news items showed just how challenging biosecurity can be, as farmers and ranchers learn more about diseases.
First is news that five mink in Utah have been identified to have been infected with COVID-19, or SARS-CoV-2. The animals came from two different mink farms, and the infections were confirmed in USDA’s National Veterinary Service Laboratory.
According to the Utah Department of Agriculture and Food, the Utah Veterinary Diagnostic Laboratory completed necropsies on several dead animals from the two mink farms after the operations reported unusually high mortality rates in their mink populations. The samples were tested at the Washington Animal Disease Diagnostic Laboratory at Washington State University. From there, the samples were sent to USDA’s NVSL facility for confirmational testing.
The two mink farms have been completely quarantined to stop the spread of the disease.
Dean Taylor, Utah state veterinarian, notes that his office is focused on containing SARS-CoV-2 “by implementing stringent biosecurity measures where needed. We believe that our early detection of the virus will prove beneficial in the long run.”
The two affected Utah mink farms also reported cases of COVID-19 in staff members. However, UDAF notes there is currently no evidence that animals, including mink, play a significant role in transmitting the virus to humans. The agency reports that based on limited information and research, the risk of animals spreading SARS-CoV-2 to humans is considered low.
Other animal species have tested positive for the disease, but these are the first cases confirmed in mink in the U.S. Earlier this year, the virus was detected in mink in the Netherlands. USDA announces cases of confirmed SARS-CoV-2 in animals each time it is found in a new species. You can check out that list online at a site supported by USDA's Animal and Plant Health Inspection Service.
An equine flu outbreak
Horses housed at Washington State University’s College of Veterinary Medicine have contracted equine influenza. The 11 horses are a USDA research herd used to study tick-borne parasite disease.
The herd is currently quarantined, and all horses are recovering under veterinary care, according to WSU.
Equine influenza is a common, highly contagious respiratory disease of horses, with a near-global distribution. It is caused by an RNA orthomyxovirus, which is unrelated to coronavirus. The equine strain of influenza is not known to infect humans or other animal species.
The most common mechanism of spread is via airborne transmission. Infected horses release infective droplets into the air by coughing or snorting, which are then inhaled by horses nearby. Horses can also be exposed to the virus by coming into contact with contaminated surfaces, such as stalls, wash racks, stocks, water sources, feed, tack, grooming equipment and transport vehicles. Humans can spread the virus from horse to horse by contaminated hands and clothing.
The affected herd at WSU is a closed herd, meaning no animals have entered or exited the premises in the last several months. Officials report that news makes determining how the infection was acquired impossible.
The incubation period for the virus is 24 to 72 hours after exposure. Signs and symptoms of the disease include fever of up to 106.0 degrees F (41.10 degrees C); lethargy; going off feed; and muscle pain and weakness, resulting in a stiff gait. Horses often develop a harsh to hacking cough, which usually precedes the fever. Nasal discharge is initially clear and watery but may vary.
No fevers have been detected in the infected herd at WSU in the last five days. Death from equine influenza is very rare. Most horses recover within 21 days.