Characterization of a French Indel strain of porcine epidemic diarrhea virus isolated in December 2014
Published:July 4, 2024
By:B. GRASLAND 1, L. BIGAULT 1, C. BERNARD 1, O. TOULOUSE 2, C. FABLET 1, F. PABOEUF 1, Y. BLANCHARD 1, N. ROSE 1 / 1 Laboratory of Ploufragan/Plouzané, Anses, PLOUFRAGAN; 2 Clinique VET Flandres, HAZEBROUCK, France.
Porcine epidemic diarrhea (PED) characterized by watery diarrhea and vomiting, was described throughout Europe till the end of the 1990’s and is caused by an Alphacoronavirus, the PED virus (PEDV). Since April 2013, a severe epizooty of PED has been striking USA previously free from this disease. Suckling piglets are the most affected by PED with up to 90-95% mortality. In China in 2010 and USA in 2013, PED epidemics were related to new PEDV strains. Today, two types of PEDV strains circulate in those countries, non-InDel and Indel strains. Since 2014, new outbreaks have been reported in Europe and only associated to InDel strains. In France PED is notifiable as emerging disease. An outbreak was reported in North of France in December 2014. The objective of the study was to characterize the PEDV isolate in the French PED outbreak, to evaluate the duration of viral shedding in feces and to compare experimentally the pathogenicity of this strain with the old European reference PEDV strain, CV777.
Materials and Methods:
The outbreak occurred in a farrow-to-finish herd located in the North of France in December 2014. Jejunum from 3 affected animals which had died within the day were sampled and used to extract the PEDV genomic RNA to determine the whole genome sequence using next-generation sequencing. RT-qPCR targeting the N gene was performed on feces sampled every 2 weeks for 2 months to assess the duration of viral shedding in the herd. The PEDV strain was used to inoculate orally three-week old specific-pathogen-free (SPF) piglets to compare the pathogenicity of this strain to the CV777 PEDV reference strain.
Results:
PEDV infection was confirmed in this herd from North of France in December 2014. The strain named PEDV FR/001/2014 is genetically related to the German GER/L00719/2014 PEDV strain (99.9% of identity) isolated in May 2014 and belongs to the Indel PEDV strains. The virus was shed in feces for 29 days in affected suckling piglets and 20 days in fattening pigs. Clinical signs typical of PED were reproduced experimentally in 3 week-old SPF piglets using FR/001/2014 PEDV strain. The virus was transmitted in one day by direct contact to other piglets. A viremia was observed in FR/001/2014- inoculated piglets compared to CV777-inoculated piglets.
Conclusion:
In conclusion, the FR/001/2014 PEDV strain was close to an Indel strain isolated in Germany few months earlier. Viral shedding decreased rapidly in PED affected animals. The virus was not transmitted to other herds. Finally, PED was experimentally reproduced in SPF piglets inoculated orally with the FR/001/2014 PEDV strain.
Disclosure of Interest: None Declared.
Keywords: diarrheal viruses.
Published in the proceedings of the International Pig Veterinary Society Congress – IPVS2016. For information on the event, past and future editions, check out https://www.theipvs.com/future-congresses/.