Herd diagnosis of low pathogen diarrhoea in growing pigs – a pilot study

Irish Veterinary Journal

Poul Bækbo²  Marie Ståhl⁴  Roberto Guedes³  Tim K Jensen⁴  Jens Peter Nielsen¹  Sven Erik Jorsal⁴  Øystein Angen⁴  Markku Johansen²  Ken Steen Pedersen² 

[1] HERD – Centre for Herd-oriented Education, Research and Development, Department of Large Animal Sciences, University of Copenhagen, Groennegaardsvej 2, DK-1870 Frederiksberg C, Denmark;Pig Research Centre, Danish Agriculture & Food Council, Axelborg, Axeltorv 3, DK-1609 Copenhagen V, Denmark;Department of Veterinary Clinics and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte MG 31.270-901, Brazil;National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1790 Copenhagen V, Denmark

关键词: Quantitative polymerase chain reaction;    Low pathogen diarrhoea;    Diagnostic procedures;   

Others  :  1133614
DOI  :  10.1186/2046-0481-67-24

 received in 2014-04-01, accepted in 2014-10-08,  发布年份 2014

【 摘 要 】

Background

The major indication for antibiotic use in Danish pigs is treatment of intestinal diseases post weaning. Clinical decisions on antibiotic batch medication are often based on inspection of diarrhoeic pools on the pen floor. In some of these treated diarrhoea outbreaks, intestinal pathogens can only be demonstrated in a small number of pigs within the treated group (low pathogen diarrhoea). Termination of antibiotic batch medication in herds suffering from such diarrhoea could potentially reduce the consumption of antibiotics in the pig industry. The objective of the present pilot study was to suggest criteria for herd diagnosis of low pathogen diarrhoea in growing pigs.

Data previously collected from 20 Danish herds were used to create a case series of clinical diarrhoea outbreaks normally subjected to antibiotic treatment. In the present study, these diarrhoea outbreaks were classified as low pathogen (<15% of the pigs having bacterial intestinal disease) (n =5 outbreaks) or high pathogen (≥15% of the pigs having bacterial intestinal disease) (n =15 outbreaks). Based on the case series, different diagnostic procedures were explored, and criteria for herd diagnosis of low pathogen diarrhoea were suggested. The effect of sampling variation was explored by simulation.

Results

The diagnostic procedure with the highest combined herd-level sensitivity and specificity was qPCR testing of a pooled sample containing 20 randomly selected faecal samples. The criteria for a positive test result (high pathogen diarrhoea outbreak) were an average of 1.5 diarrhoeic faecal pools on the floor of each pen in the room under investigation and a pathogenic bacterial load ≥35,000 per gram in the faecal pool tested by qPCR. The bacterial load was the sum of Lawsonia intracellularis, Brachyspira pilosicoli and Escherichia coli F4 and F18 bacteria per gram faeces. The herd-diagnostic performance was (herd-level) diagnostic sensitivity =0.99, diagnostic specificity =0.80, positive predictive value =0.94 and negative predictive value =0.96.

Conclusions

The pilot study suggests criteria for herd diagnosis of low pathogen diarrhoea in growing pigs. The suggested criteria should now be evaluated, and the effect of terminating antibiotic batch medication in herds identified as suffering from low pathogen diarrhoea should be explored.

【 授权许可】

   
2014 Pedersen et al.; licensee BioMed Central Ltd.

【 参考文献 】

• [1]Collignon P, Powers JH, Chiller TM, Aidara-Kane A, Aarestrup FM: World Health Organization ranking of antimicrobials according to their importance in human medicine: a critical step for developing risk management strategies for the use of antimicrobials in food production animals. Clin Infect Dis 2009, 49:132-141.
• [2]Hybschmann GK, Ersboll AK, Vigre H, Baadsgaard NP, Houe H: Herd-level risk factors for antimicrobial demanding gastrointestinal diseases in Danish herds with finisher pigs: a register-based study. Prev Vet Med 2011, 98:190-197.
• [3]Jensen HM: Health management with reduced antibiotic use - experiences of a Danish pig vet. Anim Biotechnol 2006, 17:189-194.
• [4]Chase-Topping ME, Gunn G, Strachan WD, Edwards SA, Smith WJ, Hillman K, Stefopoulou SN, Thomson JR: Epidemiology of porcine non-specific colitis on Scottish farms. Vet J 2007, 173:353-360.
• [5]Pedersen KS, Kristensen CS, Nielsen JP: Demonstration of non-specific colitis and increased crypt depth in colon of weaned pigs with diarrhea. Vet Q 2012, 32:45-49.
• [6]Pedersen KS, Stahl M, Guedes RM, Angen O, Nielsen JP, Jensen TK: Association between faecal load of lawsonia intracellularis and pathological findings of proliferative enteropathy in pigs with diarrhoea. BMC Vet Res 2012, 8:198. BioMed Central Full Text
• [7]Pedersen KS, Stege H, Jensen TK, Guedes R, Stahl M, Nielsen JP, Hjulsager C, Larsen LE, Angen O: Diagnostic performance of fecal quantitative real-time polymerase chain reaction for detection of Lawsonia intracellularis-associated proliferative enteropathy in nursery pigs. J Vet Diagn Invest 2013, 25:336-340.
• [8]Boye M, Jensen TK, Moller K, Leser TD, Jorsal SE: Specific detection of the genus Serpulina, S. hyodysenteriae and S. pilosicoliin porcine intestines by fluorescent rRNA in situ hybridization. Mol Cell Probes 1998, 12:323-330.
• [9]Moller K, Jensen TK, Jorsal SE, Leser TD, Carstensen B: Detection of Lawsonia intracellularis, Serpulina hyodysenteriae, weakly beta-haemolytic intestinal spirochaetes, Salmonella enterica, and haemolytic Escherichia coli from swine herds with and without diarrhoea among growing pigs. Vet Microbiol 1998, 62:59-72.
• [10]Stahl M, Kokotovic B, Hjulsager CK, Breum SO, Angen O: The use of quantitative PCR for identification and quantification of Brachyspira pilosicoli, Lawsonia intracellularis and Escherichia coli fimbrial types F4 and F18 in pig feces. Vet Microbiol 2011, 151:307-314.
• [11]Pedersen KS, Johansen M, Jorsal SE, Nielsen JP, Bækbo P, Angen Ø: Pooling of porcine fecal samples for quantification of Lawsonia intracellularis by real-time polymerase chain reaction. J Vet Diagn Invest 2014, 26:342-345.
• [12]Frydendahl K: Prevalence of serogroups and virulence genes in Escherichia coli associated with postweaning diarrhoea and edema disease in pigs and a comparison of diagnostic approaches. Vet Microbiol 2002, 85:169-182.