High susceptibility prevalence for F4+ and F18+Escherichia coli in Flemish pigs.

F4 and/or F18 enterotoxigenic Escherichia coli (F4+/F18+ ETEC) are responsible for diarrhea while F18+ verotoxigenic E. coli (F18+ VTEC) cause edema disease in pigs. Both infections can result in severe economic losses, which are mainly the result of the medication, growth retardation and mortality. The susceptibility of piglets to these pathogens is determined by the presence of F4 and F18 receptors (F4R and F18R). Understanding the composition of the susceptibility phenotypes of pigs is useful for animal health and breeding management. This study aimed to determine the prevalence of the F4 ETEC susceptibility phenotypes and F18+E. coli susceptibility among Flemish pig breeds by using the in vitro villous adhesion assay. In this study, seven F4 ETEC susceptibility phenotypes were found, namely A (F4abR+,acR+,adR+; 59.16%), B (F4abR+,acR+,adR-; 6.28%), C (F4abR+,acR-,adR+; 2.62%), D (F4abR-,acR-,adR+; 6.28%), E (F4abR-,acR-,adR-; 24.08%), F (F4abR+,acR-,adR-; 1.05%) and G (F4abR-,acR+,adR-; 0.52%). F4ab and F4ac E. coli showed a stronger degree of adhesion to the intestinal villi (53.40% and 52.88% strong adhesion, respectively), compared to F4ad E. coli (43.46% strong adhesion). Furthermore, the correlation between F4ac and F4ab adhesion was higher (r=0.78) than between F4ac and F4ad adhesion (r=0.41) and between F4ab and F4ad adhesion (r=0.57). For F18+E. coli susceptibility, seven out of 82 pigs were F18R negative (8.54%), but only two of these seven pigs (2.44%) were also negative for F4R. As such, the chance to identify a pig that is positive for a F4 ETEC variant or F18+E. coli is 97.56%. Therefore, significant economic losses will arise due to F4+ and/or F18+E. coli infections in the Flemish pig population due to the high susceptibility prevalence.