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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #331105

Title: PEDV exposure protects pigs against homologous re-exposure 44 days later

item OPRIESSNIG, TANJA - Roslin Institute
item GERBER, PRISCILLA - Iowa State University
item XIAO, CHAOTING - Iowa State University
item Lager, Kelly
item CRAWFORD, KIMBERLY - Orise Fellow
item KULSHRESHTHA, VIKAS - Orise Fellow
item CAO, DIANJUN - Virginia Tech
item MENG, XIANG-JIN - Virginia Tech

Submitted to: International Pig Veterinary Society (IPVS)
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction PEDV emerged in the US during 2013 and rapidly spread from farm to farm causing high morbidity and mortality resulting in high economic losses to the US swine industry. As the virus made its way through swine dense populations there were many questions on degree and length of protection after initial exposure. The objective of this study was to determine if initial expose of a group of pigs to a PEDV genogroup 2 prototype strain induced homologous protection against re-challenge. Materials and Methods Sixty 10-day old pigs were used; 32 pigs were orally infected with PEDV Co-13 at 10 days of age (=day 0). All sixty pigs were orally infected with PEDV Co-13 44 days later (=day 44) when the pigs were approximately 8 weeks old. Fecal swabs were collected daily and tested by a PEDV real-time PCR for PEDV RNA. In addition, serum was collected at day 0, 7, 14, 24, 44 and day 58-60 to test for PEDV-specific IgG and IgA by ELISA. Pigs were randomly selected for necropsy at 3, 14, or 16 days after re-challenge. Results After initial infection at day 0, pigs started to shed PEDV in feces from day 1 onwards. Essentially all samples from all infected pigs were positive until day 8 at which time shedding became intermittent but continued over the following weeks. Two of the 32 pigs were still PCR positive on feces by day 44. PEDV IgA antibodies were detected in two infected pigs by day 7 and most infected pigs were IgA positive by day 14. IgA levels were still high at the time of re-challenge. Six of the 32 pigs had detectable IgG levels by day 7 and 19/32 were IgG PEDV positive at day 21. At day 24 and 44 all pigs were IgG positive. After re-challenge, PEDV RNA was detected in a fecal sample from one pig whereas the majority of the pigs without previous PEDV exposure were PCR positive by day 2. After re-challenge randomly selected pigs in both groups were necropsied at 3, 14 or 16 days post challenge. Lesions or PEDV antigen were not detected in any of the exposed pigs whereas naïve pigs had moderate lesions in enteric sections associated with moderate to high amount of PEDV antigen. Conclusions Results indicate that previous expose to PEDV can induce protective homologous immunity within 44 days providing insight to the duration of immunity.