Recent research suggests that Porcine Ear Necrosis Syndrome is multifactorial in origin and that although infectious agents can be involved in the development of the syndrome they are not the exclusive triggering factor.
The study to Porcine Ear Necrosis Syndrome (PENS) was carried out by Austrian, Swiss and German researchers.
The aim of this study was to identify the causative factors of porcine ear necrosis syndrome in 72 pigs, 5.5-10 weeks in age housed on nine farms.
Biopsy samples of ear pinnae were collected from all piglets for bacteriology, histopathology and in situ hybridisation for porcine circovirus type 2 (PCV2).
At the same time, serum samples were taken for serological analysis and viral PCR, and feed was sampled for mycotoxin analysis.
The initial lesion of PENS seemed to be a focal epidermal necrosis. Streptococci were isolated from 44 and staphylococci from 36 pinnae.
PCV2 could not be detected by in situ hybridisation or qPCR. Seven piglets were positive for porcine reproductive and respiratory syndrome virus, and one for Mycoplasma suis. One piglet had antibodies against Sarcoptes scabiei var. suis. No infectious agents were found in 15 samples.
Positive virology and parasitology were often found alongside positive bacteriology. Deoxynivalenol, zearalenone and ergot alkaloids were detected in feed.