US researchers compared the efficacy of two different ways of immunisation against Porcine Epidemic Diarrhoea virus (PEDv). The oral route appeared the more efficacious method, especially when looking at the production of milk antiviral antibody levels.
PEDv was first detected in the United States in May 2013 and has had a detrimental effect on especially multiplication farms, with sometimes up to 100% of the newborn piglets dying. Just like with Transmissible Gastro-Enteritis virus (TGEv), providing intestinal tracts from euthanised infected neonates to gilts and sows, has been a strategy to control PEDv.
Ever since the outbreak, various vaccines have been developed to control PEDv. For this research, iPED+ from Harrisvaccines, Ames, IA, United States was compared to the oral route. The company was acquired by Merck Animal Health late last year.
Also read – PEDv: An intercontinental update
The researchers write that they examined, in unrelated swine production units in different locations, the immune responses (serum anti-PEDv immunoglobulin G (IgG) and milk antiviral neutralising antibodies) induced by various combinations of both vaccine and oral immunisation.
The researchers wrote in their conclusion, “Anti-PEDv antibodies were undetectable in serum and milk of the control group (non-vaccinated and non-infected). Sows in the unit that received only two doses of the PED vaccine remained naive for the wild-type virus and did not develop milk anti-PEDv neutralising immunoglobulin titres as high as those in the other three production units, which had received oral immunisation.
They continue: “Milk anti-PEDv antibody titres in the orally immunised sows appeared to be of longer duration than serum antiviral IgG concentrations. This indicates that oral immunisation may be the more efficacious PEDv immunisation modality, especially with regard to the production of milk antiviral antibody levels.”
The research paper, ‘Evaluation of responses to both oral and parenteral immunization modalities for porcine epidemic diarrhea virus in production units‘ was authored by Gail Scherba, DVM, PhD, Corinne R. Bromfield, DVM, Vickie L. Jarrell, PhD and Clifford F. Shipley, DVM, Diplomate ACT, University of Illinois, Urbana, IL, United States.