Protection of piglets against porcine epidemic diarrhea virus

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					          Protection of piglets against porcine epidemic diarrhea virus (PEDV) using sow oral administration
                                          of cell culture-attenuated Thai PEDV

                                  Mongkol Lumyai1, Porjit Choojai2, Roongroje Thanawongnuwech1 , Komkrich Teankum1
              Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
              Veterinary Diagnostic Laboratory, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand

                  Introduction                                                              Figure 2: Virus titers in gut of piglets challenged orally with
                  Porcine epidemic diarrhea virus (PEDV), a member of                       the virulent Thai PEDV.
                  Coronavirus, causes severe enteric disease especially in
                  suckling piglets with high mortality reaching up to 90%.
                  Similar to other viral enteritis virus, PEDV replicates in                                     5
                  differentiated enterocytes covering the villi of the small
                  intestine, leading to villous atrophy and malabsorption.                                       4

                                                                                            Virus titer(log10)
                  Recently, PEDV is one of the most important diseases
                  causing economic loss in Thailand and other Southeast                                          3                                          group1
                  Asian countries. The objective of this study was to study
                  the protection of piglets deriving from pregnant sows                                          2
                  receiving cell culture-attenuated Thai PEDV orally against
                  wild type PEDV challenge.                                                                      1

                  Materials and Methods
                                                                                                                     12   24      48       72   120
                     PEDV serial propagation in Vero cell passages 53
                                                                                                                          Hour post challenge

                                        Pregnant sows
                      (orally inoculation 4 and 2 wk before farrowing)                      Results and Discussions
                                                                                            Pregnant sows inoculated with the attenuated Thai PEDV
                    Group 1; Orally inoculation                Group 2; Control             did not show any clinical signs of the disease or viral
                              (n=3)                                 (n=1)                   shedding from fecal content. All piglets challenged with the
                                                                                            virulent Thai PEDV exhibited diarrhea within 48 hrs but
                                                                                            shown only 62% in the vaccinated group at 24 hrs after
                                       - Clinical observation                               challenge (Fig. 1). Both groups yielded positive RT-PCR
                                       - Detection of viral RNA                             detection in feces but the virus titers tested in the small
                                        in feces using RT-PCR                               intestine of the control piglets had somewhat higher titers
                                                                                            than the piglets derived from vaccinated sows, particularly
                                                                                            at 48 hour post challenged (Fig. 2). It should be noted that
                         Piglets from immunized & non-immunized sow
                                                                                            the PEDV challenged dosage would have been higher
                                (challenged with wild-type PEDV)
                                                                                            resulting in more severe clinical disease than expected.
                                                                                            These results indicated that oral administration with the
                                                                                            cell culture-attenuated Thai PEDV in pregnant sows could
                                                                                            partially reduce clinical signs and virus shedding in piglets
                      Clinical        Viral RNA detection in             Virus titration;   against virulence PEDV challenge.
                    observation           feces: RT-PCR                  Small intestine
                                                                                            We would like to thank the staffs from Veterinary
                                                                                            Diagnostic Laboratory and Department of Veterinary
                                 Protection of piglets from PEDV challenge                  Pathology, Faculty of Veterinary Science, Chulalongkorn
                                                                                            University for laboratory assistants and financial support
            Figure 1: Percentage of diarrhea signs in piglets
                                                                                            from the National Research Council of Thailand.
             challenged orally with the virulent Thai PEDV strain
                                                                                            1. De Arriba, M.L. et al. 2002. Vet. Immunol.
                   100                                                                         Immunopathol. 85, 85-97.
                                                                                            2. Kim, O. and Chae, C. 2003. J. Comp. Path. 129,
% Diarrhea sign

                    60                                                            group1    3. Kweon, C.H. et al. 1999. Vaccine 17. 2546-2553.
                                                                                  group2    4. Song, D.S. et al. 2007. Res. In Vet. Science 82,
                    40                                                                         134-140.

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                                     Day post challe nge

                         Proceedings of the 5th Asian Pig Veterinary Society Congress
                         7-9 March 2011, Pattaya, Thailand

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