Microbiological, pathological and histological findings in four Danish pig herds affected by a new neonatal diarrhoea syndrome

Abstract

BackgroundNeonatal diarrhoea is a frequent clinical condition in commercial swine herds, previously regarded to be uncomplicated to treat. However, since 2008 it seems that a new neonatal diarrhoeic syndrome unresponsive to antibiotics and common management practices has emerged. Routine laboratory examinations have not detected any pathogen related to this syndrome. The primary purpose of this study was to evaluate if well-known enteric pathogens could be associated with outbreaks of neonatal diarrhoea, thus question the hypotheses of a new syndrome. Furthermore, we wanted to evaluate macroscopic and microscopic findings associated with these outbreaks and if possible propose a preliminary piglet-level case-definition on syndrome New Neonatal Porcine Diarrhoea syndrome (NNPDS).ResultsFour well-managed herds experiencing neonatal diarrhoea with no previously established laboratory conclusion and suspected to suffer from New Neonatal Porcine Diarrhoea Syndrome, were selected. Within these herds, 51 diarrhoeic and 50 non-diarrhoeic piglets at the age of three to seven days were necropsied and subjected to histological and microbiological examination. Faeces were non-haemorrhagic. Neither enterotoxigenic E. coli, Clostridium perfringens type A or C, Clostridium difficile, rotavirus, coronavirus, Cryptosporidium spp, Giardia spp, Cystoisospora suis nor Strongyloides ransomi were associated with diarrhoea in the investigated outbreaks. Macroscopically, the diarrhoeic piglets were characterized by filled stomachs and flaccid intestines without mucosal changes. The predominant histological lesions were villous atrophy in jejunum and ileum. Epithelial lesions in colon were seen in one third of the case piglets.ConclusionsThe results of the study supported the hypothesis that a new neonatal porcine diarrhoea was present in the investigated herds, since no known pathogen(s) or management factors could explain the diarrhoeal outbreaks. Based on the findings in the four herds the following case-definition of NNPDS was suggested: Non-haemorrhagic diarrhoea during the first week of life, without detection of known infectious pathogens, characterized by milk-filled stomachs and flaccid intestines at necropsy.

Pathological and bacteriological characterization of neonatal porcine diarrhoea of uncertain aetiology

“…The existence of an NNPDS unassociated with previously acknowledged enteropathogens has therefore been suggested (Kongsted et al, 2013). Our investigation of NPD in 10 Swedish herds indicated that bacteria commonly associated with piglet diarrhoea were rare (ETEC), absent (Clostridium perfringens type C) or apparently unrelated to the diarrhoea (Clostridium perfringens type A and Clostridium difficile).…”

“…Flaccidity and dilation of the intestine were common among the diarrhoeic piglets, a gross pathology consistent with NNPDS (Kongsted et al, 2013). However, these findings, as well as the hyperaemia of the small intestine in some piglets, are common in neonatal diarrhoea irrespective of its cause (Brown et al, 2007).…”

“…Different hypotheses about the underlying causes include the presence of an unknown infectious agent, introduction of new variants of previously acknowledged pathogens (mainly Escherichia coli) or changes in the environment or immune status of the piglets. Kongsted et al (2013) describe the problem as a new neonatal porcine diarrhoea syndrome (NNPDS), which they define as nonhaemorrhagic diarrhoea during the first week of life, without detection of well-known infectious pathogens, and characterized by milk-filled stomachs and flaccid intestines at necropsy. However, systematic microbiological and pathological investigations are few and the results inconclusive (Jonach et al, 2014;Kongsted et al, 2013).…”

Post-mortem findings and piglet mortality in relation to strategic use of straw at farrowing

“…Since 2008, field experiences of a new diarrhoeic syndrome have been reported in several countries including Sweden, referred to by some authors as the New Neonatal Porcine Diarrhoea Syndrome (NNPDS) (Kongsted et al, 2013;Melin et al, 2010). No known pathogens or management factors causing the outbreaks has to our knowledge yet been identified.…”

Farm characteristics and management routines related to neonatal porcine diarrhoea: a survey among Swedish piglet producers

“…In recent years however, reports from a number of countries, including Sweden, describe problems with NPD despite the use of previously effective preventive measures [17–20]. The underlying causes for this problem, by some referred to as new neonatal porcine diarrhoea syndrome (NNPDS), is currently unknown and hitherto well-known porcine enteropathogens seem to be of minor importance [17, 19, 20]. …”