by George Looby
Outbreaks of new and emerging diseases are forever lurking in the shadows. The target of the ongoing viral disease caused by a coronavirus is the human population.
Members of this family of viruses have been around a long time and in recent years have created headlines that most of us will recall. The common cold is a member of this family. Among the more aggressive family members are SARS (severe acute respiratory syndrome) virus and MERS (Middle East respiratory syndrome) which can infect both human and animal. The virus gets its name from its appearance when viewed under a microscope. It appears like a small crown with a ring of projections.
The turkey coronavirus (TCV) is one that damages turkey operations. It is most aggressive in young poults but the economic impact is felt most in young adults approaching market age which fail to gain weight at an acceptable rate, thus lessening their overall value. The virus is shed in the feces and continues to be shed for several weeks after recovery. Spread may be facilitated by humans, birds, vehicles, bats, dogs and many other agents.
Another member virus family causes a condition called vomiting and wasting disease (VWD) in baby pigs. This condition is also known as porcine hemagglutinating encephalomyelitis virus (PHEV) or coronaviral encephalomyelitis. In most established herds it remains subclinical, as there is usually a herd immunity – an individual sow’s milk contains adequate antibodies to protect their litters until age immunity takes over. It appears to affect only those less than four weeks old. An outbreak on an individual farm may last two to three weeks, by which time pregnant sows will have had the opportunity to develop maternal antibodies. Piglets born to such sows benefit from the antibody-rich colostrum which protects them from the virus.
As if to prove that it shows no favorites, there is a coronavirus that affects dogs. The many different coronaviruses tend to be species specific, though, so the variety that infects dogs poses no threat to humans. Puppies appear to be most susceptible, with most episodes rather short-lived. Diarrhea in puppies is very common, with often more than one agent contributing to the problem. In most cases crowding and unsanitary conditions contribute to the spread of the disease. A high level of good sanitation will do much to solve the problem.
At present, it appears there is little to fear about coronaviruses in domestic livestock posing a risk to human health. Be alert and follow the course of preventative action suggested by public health officials.