Jordà*1, R.; García1, G. ; Bernal1, I.; Álvarez1, G.; Nodar1, L.
1Hipra, Amer(Girona), Spain.
*Corresponding author: ramon.jorda@hipra.com
Background and Objectives
Oedema disease (OD) is an enterotoxaemia caused by Escherichia coli, which possesses adhesion factors enabling the bacteria to colonise the small intestine and produce the verotoxin 2e (VT2e). VT2e is absorbed into the bloodstream and causes vascular damage, growth problems, nervous disorders and mortality. The incidence of this disease has increased in recent years due to the ban on the use of ZnO as a veterinary medicinal product (VMP) in Europe (EU- 2019/6) and the global trend towards a reduction in the use of antibiotics. The aim of this study was to determine which are the best periods for detection of the VT2e on swine farms throughout the world.
Materials & Methods
Verocheck (HIPRA) is a sampling test (qPCR) that checks for the E. coli gene that codes for the VT2e in oral fluids which are transferred to FTA Elute cards(1) (Ct value: POS <38.5). A total of 3,785 farms from 47 different countries, with a total of 19,633 samples, were analysed from January 2017 to September 2023. The different ranked ages were from less than 4 weeks (w), 4-8 w, 8-12 w, 12-16 w and over 16 w. A farm was considered positive when at least one of the samples was positive.
Results
The age with the highest percentage positivity for VT2e was 12-16 w (64.1%) (c), followed by >16 weeks (63.3 %) (c), then 8-12 weeks(54.8%) (b), and finally, 4-8 weeks (48 %) (a) and < 4 weeks (34.2 %) (a) (Figure 1). Different letters indicate statistically significant differences on a logistic regression model.
However, the highest percentage of VT2 epositive farms with a high amount of the VT2e gene detected (+++) was in the 7-8 weeks age group (17.3%), followed by 5-6 weeks of age (16%).
Discussion & Conclusion
The expression of fimbria 18 (F18) in the small intestine occurs from 3 weeks of age onwards (2). This factor, together with the high use of antibiotics and additives during the first weeks of life and in the nursery period, may play a role in the low prevalence of VT2e observed in the earliest age groups (especially in those countries where the use of ZnO
is still allowed).
These results are relevant for field veterinarians because they may sug- gest high economic losses if the VT2e is present at later ages (>12 wee- ks), as this could indicate clinical or subclinical losses directly related to the VT2e effects, and co-infections with other pathogens. Based on this diagnostic finding, we would suggest that the best ages to sample are between 5 and 6 weeks up to 9-10 weeks of age.
References
1. Valls, L. et al. 2018. Improving edema disease diagnosis in pigs by detecting the vt2e toxin gen in oral fluid by qPCR. ESPHM proceedings.
2. Fairbrother J. et al. 2019, Disease of Swine, Eleventh Edition 807-811.
