EPIDEMIOLOGICAL CHARACTERISTICS OF POST-WEANING DIARRHOEA ASSOCIATED WITH TOXIN-PRODUCING ESCHERICHIA COLI IN LARGE INTENSIVE PIG FARMS
2011
Lyutzkanov, M., Thracian University, Stara Zagora (Bulgaria)
Post-weaning diarrhoeas are a common health problem in intensively reared pigs. The present report presents data about their prevalence in 8 intensive farms from various regions in Bulgaria during 2005–2009. A total of 898 faecal or intestinal content samples were collected from pigs in the period after weaning to their arrival in fattening herds and submitted to bacteriological examination. A single microbial agent was detected in 57.5% of samples, and two or more agents in the other. They belonged to 10 taxonomic categories. Toxin-producing E.coli belonging to the enterotoxigenic and enterohaemorrhagic pathovar were detected in 66.1% of 619 isolated and identified strains. Out of them, 87.4% possessed the adhesion factor F18 while the rest – adhesin of the F4 type. E.coli-associated diarrhoeas appeared mainly in the first 3–4 weeks after weaning, most commonly during the second weeks. That is when the highest incidence has been detected. They were caused by both toxicogenic E. coli as well as by a number of predisposing factors. In surveyed farms, they were most commonly related to feeding regimen and feeding rations. The prevalence varied from 14.1 tо 29.6%. The total morbidity rate was between 19.2 and 51.5%, and the lethality – from 1.22 tо 11.73%. Post-weaning diarrhoeas associated with enterohaemorrhagic E. coli were prevalent over the whole year but higher morbidity rates were observed during the cold and wet months of the year.
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