Faeces samples from calves with diarrhoea in 45 outbreaks were examined for six enteropathogens. Rotavirus and coronavirus were detected by ELISA in 208 (42 per cent) and 69 (14 per cent) of 490 calves respectively; calici-like viruses were detected by electron microscopy in 14 of 132 calves (11 per cent). Cryptosporidium were detected in 106 of 465 (23 per cent), Salmonella species in 58 of 490 (12 per cent) and enterotoxigenic Escherichia coli bearing the K99 adhesin (K99+ E coli) in nine of 310 calves (3 per cent). In the faeces of 20 per cent of calves with diarrhoea more than one enteropathogen was detected; in 31 per cent no enteropathogen was found. Faces samples from 385 healthy calves in the same outbreaks were also examined. There was a significant statistical association of disease with the presence of rotavirus, coronavirus, Cryptosporidium and Salmonella species (P less than 0.001). Healthy calves were not examined for calici-like viruses and the association of K99+ E coli with disease was not analysed because there were too few positive samples. Rotavirus infections were more common in dairy herds and single suckler beef herds whereas Salmonella infections were more often found in calf rearing units. Cryptosporidium were more common in single and multiple suckler beef herds. K99+ E coli were found in one dairy herd and one multiple suckler beef herd both with unhygienic calving accommodation. Variations in coronavirus detection among different farm types were not statistically significant. In this survey rotavirus was the most commonly detected agent in calf diarrhoea and Cryptosporidium were found in approximately one quarter of affected calves. Infection with Salmonella species was widespread, but K99+ E coli infections were less common in the United Kingdom than in other countries.

A dysentery syndrome was recognized among the Institute's calves at 18 to 21 days of age. It was reproduced experimentally in gnotobiotic calves with an atypical Escherichia coli (S102-9) isolated from the affected calves. In both natural and experimental disease the calves passed copious bright red blood in the feces and developed diarrhea. Walls of the colon and rectum were thickened, and the mucosa was reddened and covered by an exudate that contained mucus and blood clots. Bacteria were seen closely adherent to the luminal surfaces of enterocytes, often in cup-shaped depressions or on cytoplasmic pedestals. Microvilli were distorted, disorientated or absent. There was exfoliation of infected enterocytes and a mild acute inflammation of the underlying lamina. In two of five calves with natural disease, the adherent bacteria did not stain by the immunoperoxidase method with antisera raised against E. coli (S102-9). This indicated that there was possibly more than one bacterial cause of the syndrome. Lesions in experimentally infected calves were indistinguishable from those produced by some E. coli which are enteropathogenic for man, rabbits, and pigs.

SUMMARYIn a survey of chicken coccidia in France during 1994, samples of litter were collected from 41 farms. On 31 of these farms, eimerian oocysts were abundant enough to allow monitoring of their numbers in the litter. Peak total oocyst counts on these farms ranged from 16,200 to 1,254,000/g of litter, but no coccidiosis was observed. The chickens reared without anticoccidial agents in their food (poulets biologiques) produced higher and earlier peak oocyst counts in litter than the chickens given medicated food (poulets labels). The oocysts in litter samples from 22 farms (13 poulet biologique, five poulet label, two standard broiler, one breeder and one layer) of the original 41 were identified. Six of the seven eimerian species known to parasitize chickens were found, using combinations of five methods (oocyst morphology, intestinal lesions, enzyme electrophoresis, growth in embryonating eggs and prepatent time). Multispecific infections predominated (95% of 22 farms), up to six species occurring together. Of farms where oocysts were detected, the percentages with each species were: Eimeria acervulina (100%), E. mitis (82%), E. tenella (77%), E. maxima (73%), E. praecox (45%) and E. brunetti (27%). These appear to be the first definite records of E. mitis and E. praecox for France. Although E. necatrix was not found in this survey, it had recently been detected by other workers in France, so that all seven chicken Eimeria species were known to be contemporaneous.

Twelve intestinal spirochete strains of porcine origin were characterized on the basis of their phenotypic properties, by multilocus enzyme electrophoresis, and by pathogenicity testing in gnotobiotic pigs. The spirochetes used included two strains of Serpulina hyodysenteriae (B204 and P18A), two strains of Serpulina innocens (B256 and 4/71), one strain from the proposed new genus and species "Anguillina coli" (P43/6/78), and seven non-S. hyodysenteriae strains recently isolated from United Kingdom pig herds with a history of nonspecific diarrhea and typhlocolitis. By multilocus enzyme electrophoresis, five of these were identified as S. innocens, one was identified as an unspecified Serpulina sp., and one was identified as "A. coli." S. hyodysenteriae B204 and P18A, "A. coli" P43/6/78 and 2/7, and three (22/7, P280/1, and 14/5) of the five S. innocens field isolates induced mucoid feces and typhlocolitis in gnotobiotic pigs. None of the other spirochetes produced clinical signs or large intestinal pathology in this model. The "A. coli" strains induced a more watery diarrhea, with lesions present more proximally in the large intestine, than did the other pathogenic spirochetes. S. innocens 22/7 was also tested for pathogenicity in hysterotomy-derived pigs that had previously been artificially colonized with a spirochete-free intestinal flora and shown to be susceptible to swine dysentery. Despite effective colonization, strain 22/7 did not produce any disease, nor was there any exacerbation of large intestinal pathology or clinical signs when pigs with an experimentally induced existing colitis caused by Yersinia pseudotuberculosis were superinfected with strain 22/7. Certain non-S. hyodysenteriae spirochetes are therefore capable of inducing disease in gnotobiotic pigs, but their role as primary or opportunistic pathogens in conventional pigs remains equivocal.

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