A terrible disease has reared its ugly head in the porcine industry in the United States. On May 17, 2013, the presence of Porcine Epidemic Diarrhea Virus, of PEDV was confirmed to have made its way into the U.S. Previously known to exist in Great Britain (first diagnosed in 1971) as well as sporadically in Europe, PEDV has been commonly found in Asia since the early 1980's where it is known to be a major problem.
While this disease is also a coronavirus and is related to Transmissible Gastroenteritis Coronavirus (TGEV) for which immunity is present, PEDV is not protected under the same umbrella of immunity despite the relation between the two. Similarly to TGEV, PEDV presents in the form of severe diarrhea which affects pigs regardless of age and is spread through fecal matter that is accidentally ingested. While pig-to-pig is the primary means of spread, it can also be spread on fomites (contaminated inanimate objects capable of aiding in the transmission of infectious organisms) such as shoes, supplies, shipping trucks, and other such means.
Upon exposure, incubation takes less than 24 hours, after which the virus is shed for a week to ten days. Sows or gilts with immunity can provide protection to piglets but only while they are nursing. Antibodies are passed through the milk, but once they are weaned and no longer receiving those antibodies, they will then be susceptible to infection upon exposure to PEDV. Beyond that a mortality rate of 30-100% is possible. At this time there are no other known hosts affected by this virus. It does not appear to be systemic and does not affect other organs, remaining instead in the enterocytes lining intestines. To combat this illness, supportive treatment is recommended, which entails keeping pigs as comfortable and well hydrated as possible. Clean, dry environments are important as is access to drinking water free of contaminants. Since diarrhea will deplete fluids form your pigs, supplementing electrolytes may be helpful to them.
Quarantining affected animals and practicing good biosecurity are the only ways to keep this disease from further spread. If pigs are not coming or going from your farm, regulating fomites is the most important tactic you can embrace in the fight against PEDV. Since this disease can be transmitted on inanimate objects, be sure to sterilize everything that has been given access to pigs at another location. This means changing your own shoes and clothing as well as scrubbing exposed skin to prevent the possibility of transmission. It also means sterilizing stock trucks and trailers to make sure the virus is not transmitted when pigs are transported. Several disinfectants will kill PEDV, such as Clorox, Virkon S, 1 Stroke Environ, and Tek-Tol. Heat will kill it as well as long as temperatures higher than 150 degrees Fahrenheit are reached and sustained for over ten minutes.
At this time there is no vaccine against PEDV though its losses have been tremendous. It is wise to prepare for a veterinary consultation if illness arises in your herd; your vet can likely also keep you abreast of ill pigs in your area so you can avoid contact with them. In order to prevent diseases such as PEDV, you have to consider the big picture, and the big picture can be pretty scary. The transmission of PEDV microorganisms is easier than you think and can be direct or indirect; you can do something as simple as bumping into someone who touched something tainted with PEDV and just like that, the disease will be coming home with you to change your pig operation forever. Be vigilant in your efforts of prevention and control, however, and hopefully you will have no such experience.