Date Full Report Received

05/19/2014

Date Abstract Report Received

05/19/2014

Investigation

Institution:
Primary Investigator:

The highly contagious and deadly porcine epidemic diarrhea (PED) virus (PEDv) was first discovered in the US in April-May 2013. Since then the virus has spread rapidly nationwide causing high mortality among nursing piglets and significant economic losses. Currently there are no efficacious preventive measures or therapeutic tools to control PEDv: therefore, development of an effective PEDv vaccine for swine in the US should be a high priority. Since most viruses accumulate mutations and become attenuated (reduced pathogenicity or virulence) after serial passage in cell culture, the isolation of PEDv in cell culture is the first step toward the development of an attenuated vaccine, to study the basic biology of PEDv, and to develop in vitro PEDv immunoassays, inactivation assays and screen for PEDv antivirals. Our labs have started to work on PEDv since June, 2013. What we have achieved on PEDV research is listed below:

1. We have successfully propagated one US PEDv strain PC22A in Vero cells to high titers. The isolation of PEDv in cell culture is the first step toward the development of an attenuated vaccine.

2. We have plaque-purified PC22A and generated a virus pool with high infectious titers in germfree pigs. This plaque-purified and germfree pig-passaged PC22A pool can be used as a challenge pool in future vaccine studies.
3. We have developed reverse-transcription (RT)-PCR and immunofluorescent assays (IFA) for the detection of PEDv nucleic acids and antigens, respectively. IFA and virus neutralization assay (VN) for the detection of isotype (IgA and IgG) and virus neutralizing (protective) antibodies, respectively, were also developed. Such assays are essential to: 1) screen fecal and serum samples from swine herds for PEDv prevalence; 2) detect antibodies to PEDv to determine pigs’ PEDv infection status or to permit their export if PEDv sero-negative status is required; and 3) evaluate whether a PEDv vaccine induces protective immunity.
4. We have investigated how US PEDv causes disease (pathogenesis) in nursing germfree pigs. We found that the US PEDv PC21A strain acutely infected the entire intestine, leading to severe atrophic enteritis, and is highly enteropathogenic.