Poult Enteritis Mortality Syndrome

Enteric disease, often involving diarrhea, has been a major cause of economic loss to the US poultry industry.  These losses are mainly due to decreased weight, sick birds, mortality, and increased production costs from poor feed conversions and the cost of treatment. 

Poultry enteric diseases include: poult enteritis mortality syndrome (PEMS), poult enteritis complex (PEC) and runting-stunting syndrome of broilers (RSS) as well as unclassified enteric diseases.  PEMS affects young turkeys and is probably the most severe form of enteric disease.  Although PEMS, PEC and RSS have been most severe in the Southeastern US, enteric disease is a problem in commercial poultry through-out the US.

Currently, the exact cause of PEMS and other enteric diseases is unknown.  Determining the cause of enteric disease in poultry has been difficult for several reasons.  First, definitive identification of agents has been challenging as many enteric viruses can not be grown in the laboratory and available virus detection tests have had poor sensitivity and specificity.  Secondly, enteric diseases can be caused by two or more infectious agents, and numerous agents and combinations of agents likely cause clinically similar conditions. 

With the recent development of molecular detection methods, numerous viruses have been identified in diagnostic specimens collected from turkey and chicken flocks affected by enteric disease.  Some of the most commonly identified viruses are avian reoviruses, avian astroviruses, turkey corona viruses, avian rotaviruses, and avian adenoviruses; each representing a diverse group of viruses. 

Research at SEPRL on PEMS and enteric diseases in poultry has focused on:

·  Determining what viruses cause enteric disease

·  Developing improved detection methods for enteric viruses of poultry

·  Developing control methods, such as vaccines to control or prevent the disease

·  Characterizing enteric viruses for epidemiological and genetic studies

The overall vision for SEPRL research on viral enteric diseases of poultry is to produce information that can be applied to minimize the impact of viral enteric disease on commercial poultry production.

Some accomplishments of the PEMS project include:

·  The initiation of a nation-wide survey of poultry for enteric viruses.

·  The identification of avian rotaviruses in specimens from both turkeys with poult enteritis and broiler chickens with runting-stunting syndrome. 

·  Establishing a database with gene sequences from numerous enteric viruses of poultry including avian reoviruses, avian astroviruses and avian rotaviruses.

·  The development of a state-of-the-art diagnostic technique, multiplex real-time RT-PCR, to detect turkey astrovirus, turkey coronavirus and turkey reovirus rapidly and accurately.

·  The evaluation of turkey reoviruses isolated from clinical samples collected from turkeys with poult enteritis for their ability to cause enteric disease and immune-dysfunction in poults in the absence of other viruses and for their ability to replicate and cause disease in chickens. 

·  The evaluation of numerous disinfectants for their ability to inactivate turkey astroviruses.  Two of these, formaldehyde and Virkon S, were found to be effective for inactivating the virus.

·  The identification, isolation and characterization of a unique strain of astrovirus circulating in commercial turkey flocks with PEMS.

Lead Scientist: Erica Spackman

Scientists: Mary J. Pantin-Jackwood

                   J. Michael Day