US – The very recent outbreak of Porcine Epidemic Diarrhea Virus (PEDV) in the US was of foremost concern at the World Pork Expo which kicked off today in Des Moines, Iowa, writes Chris Wright for ThePigSite.
The disease was officially confirmed on May 16, 2013, although laboratory evidence indicates that the index case occurred on Apr 16. So far eight states have confirmed the existence of the disease, and it is expected that two more states will soon be confirmed with PEDV. Iowa is one of those states with confirmed PEDV. The US Midwest has been the affected area so far.
The disease produces very high fatality rates in baby pig and young pigs, from 70 to 100 per cent. Older pigs get the disease (100% morbidity rate) but are able to recover.
A special session was set up at the expo in order to bring pig producers up to speed on what is happening with PEDV. Lisa Becton of the National Pork Board led a session to discuss the situation. She said that there is a coordinated effort by all the stakeholders in order to try and understand what has happened and how best to control it.
PEDV is similar to transmissible gastroenteritis (TGE), so this can be very misleading for producers. A laboratory confirmation is the only way to diagnose the disease and differentiate it from TGE. Some of the current cases have shown both PEDV and TGE on the same farm.
Dr. Becton stressed what PEDV is not. It is not a zoonotic disease, so it does not transmit to humans and it does not affect food safety. It is not an OIE listed disease, so it is not reportable. It is not listed as a US regulatory disease, so there are no restrictions on animal movement. Therefore it should not affect pork exports.
The clinical signs include sows with vomiting and diarrhea. Fever also seems to be involved. The diarrhea can be mild to rapid and the disease is explosive in its spread. Baby pigs under seven days old have shown a 100 per cent mortality rate. Pigs from eight to 21 days old have shown a 90 per cent mortality rate.
Confirmation of the disease has come only from sick pigs so far and not from any other sources, such as feed.
Because of the rapid pace at which this disease is spreading and the very serious nature of it, the National Pork Board has just approved the use of US$ 450,000 for PEDV research.
Following Dr. Becton’s presentation, Dr. Tom Burkgren, Executive Director of the American Association of Swine Veterinarians (AASV), discussed the current survey that is being undertaken to try and answer the key questions in this epidemic. Those questions include: Where it did come from? How is it spreading? How do we control it?
The push right now is try and find those herds that were initially affected and to try and find the source of the primary infection. Although May 16 was the date that PEDV was officially confirmed, clinical evidence now points to April 15, 2013 as the first time the disease occurred.
They are looking for those risk factors that have been common to all the cases. Many affected farms have nothing to do with each other at all. In spite of that evidence, or lack thereof, lateral transmission by trucks and trailers is the main suspect so far. The disease is spread by fecal to oral transmission. There is no aerosol spread of this disease.
Dr. Burkgren said that all the viruses that have been sampled in the US are the exact same virus. This virus is a 99.4 per cent match to a virus previously reported in China.
The immediate response by pig producers has been to really tighten up on biosecurity. “Assume that your neighbor has the disease” is the advice that is being given.
The other suggestion is for sows to be exposed to the disease so they can develop immunity. The trick, however, is to make sure the disease is controlled on the farm and that it does not become endemic.
Hopefully the survey and the new research to be undertaken will provide some answers and give direction on how best to control PEDV.
Find out more information on porcine epidemic diarrhoea (PED) by clicking here.