Association between faecal load of lawsonia intracellularis and pathological findings of proliferative enteropathy in pigs with diarrhoea
1 HERD – Centre for Herd oriented Education, Research and Development, Department of Large Animal Sciences, University of Copenhagen, Groennegaardsvej 2, Frederiksberg C 1870, Denmark
2 National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, Copenhagen V 1790, Denmark
3 Department of Veterinary Clinics and Surgery, Veterinary School, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, MG, 31.270-901, Brazil
BMC Veterinary Research 2012, 8:198 doi:10.1186/1746-6148-8-198Published: 23 October 2012
The study was designed to investigate correlation between histological findings of Lawsonia intracellularis in porcine cases of diarrhoea and the quantitative detection of Lawsonia intracellularis in faeces. A total of 156 pigs (10 to 70 days post weaning) with diarrhoea were randomly selected from 20 herds: The pigs were subjected to necropsy, histopathology, immunohistochemistry and faecal quantification of Lawsonia intracellularis by real time PCR.
The median Lawsonia intracellularis excretion was significantly higher in pigs with gross lesions of proliferative enteropathy (median excretion: 5.92 log10 bacteria/g faeces) compared to pigs without gross lesions of proliferative enteropathy (median excretion: <3.3 log10 bacteria/g faeces) (P<0.001). Spearman’s correlation coefficient between the measureable PE lesions and L. intracellularis excretion was 0.50 (P<0.001). A significantly increasing trend in Lawsonia intracellularis excretion level for increasing proliferative enteropathy histopathology and immunohistochemistry scores was demonstrated (P<0.001; P<0.001). Spearman’s correlation coefficient between the histopathology scores and L. intracellularis excretion was 0.67 (P<0.001). Spearman’s correlation coefficient between the IHC scores and L. intracellularis excretion was 0.77 (P<0.001).
The histological and quantitative PCR detection of Lawsonia intracellularis were correlated in pigs with diarrhoea. Overall the results suggest that clinically important levels for Lawsonia intracellularis excretion in faeces may be established. Such clinical threshold levels may be used in practice to confirm a diagnosis of Lawsonia intracellularis associated diarrhoea.