Neonatal diarrhoea is a multifactorial condition commonly present on pig farms and leads to economic losses due to increased morbidity and mortality of piglets, according to Beata Jonach and colleagues at the Technical University of Denmark in a paper published in BMC Veteirnary Research.

They explain that the piglet's immature immune system and lack of fully established microbiota at birth predispose neonatal piglets to infection with enteric pathogens. The microorganisms that for decades have been associated with enteritis and diarrohea in suckling piglets are rotavirus A, coronavirus, enterotoxigenic Escherichia coli (ETEC), Clostridium perfringens type C, Cryptosporidium spp., Giardia spp., Cystoisospora suis and Strongyloides ransomi.

In recent years, however, the pig industry has experienced an increased number of neonatal diarrhoea cases in which these pathogens are no longer detected. Potentially pathogenic bacteria have recently received focus in the research on the possible aetiology of neonatal diarrhoea not caused by common pathogens.

The primary aim of this Danish study was to investigate the role of E. coli, Enterococcus spp., C. perfringens and C. difficile in the pathogenesis of neonatal porcine diarrhoea with no established casual agents.

Fluorescence in situ hybridisation with oligonucleotide probes was applied on the fixed intestinal tissue samples from 51 diarrhoeic and 50 non-diarrhoeic piglets collected from four Danish farms during outbreaks of neonatal diarrhoea not caused by well-known enteric pathogens. Furthermore, an association between the presence of these bacteria and histological lesions was evaluated.

The prevalence of fluorescence signals specific for E. coli, C. perfringens and C. difficile was similar in both groups of piglets. However, Enterococcus spp. was primarily detected in the diarrhoeic piglets.

Furthermore, adherent bacteria were detected in 37 per cent of diarrhoeic and 14 per cent of non-diarroheic piglets. These bacteria were identified as E. coli and Enterococcus spp. and their presence in the intestinal mucosa was associated with histopathological changes.

Jonach and colleagues conclude their results show that simultaneous colonisation of the intestinal mucosa by adherent non-ETEC E. coli and Enterococcus spp. may be be involved in the pathogenesis of neonatal porcine diarrhoea. These bacteria should be considered in diagnosis of diarrhoea in piglets, when detection of common, well-known enteric agents is unsuccessful.

Reference

Jonach B., , M. Boye, A. Stockmarr and T.K. Jensen. 2014. Fluorescence in situ hybridization investigation of potentially pathogenic bacteria involved in neonatal porcine diarrhea. BMC Veterinary Research. 10:68 doi:10.1186/1746-6148-10-68

April 2014