INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES BY VACCINATION OF THE DAMS

Transcription

1 INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES BY VACCINATION OF THE DAMS H.V. Krogh To cite this version: H.V. Krogh. INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES BY VACCINATION OF THE DAMS. Annales de Recherches Vétérinaires, INRA Editions, 1983, 14 (4), pp <hal > HAL Id: hal Submitted on 1 Jan 1983 HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

2 INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES BY VACCINATION OF THE DAMS H.V. KROGH State Veterinary Serum Laboratory, Copenhagen, Denmark Abstract A report is given of a study on the occurrence of enterotoxigenic Escherichia coli in calves in Denmark. Samples from day-old calves were examined and ETEC were isolated from 228 samples (16.5 %). While in 1-2-day-old calves nearly one half (47.5 %) harboured ETEC, the frequency dropped to 3.4 % in 8-day-old calves, and of day-old calves just one was found to harbour ETEC. A field trial with K99-containing bacterins was performed in 14 herds with ETEC problems. A total of 109 cows were vaccinated with a 4-strain bacterin and 73 with a K99-bacterin, while 114 cows served as controls. Sixteen calves from the 4-strain bacterin group, 6 calves from the K99-bacterin group, and 25 calves from the control group, became diarrheic within their first week of life. Neonatal calf diarrhoea is a complex disease which can be caused by a number of infectious agents (Acres et al., 1975; Morin et al., 1976). These agents may act singularly or in a variety of combinations to produce essentially the same clinical syndrome. Non-infectious determinants that may promote the disease include a range of nutritional, immunological, and environmental factors. The microorganisms most commonly incriminated are Escherichia coli (E. coli), rotavirus, coronavirus, and Cryptosporidium. Infection with E. coli in calves manifests itself in at least two different syndromes (Smith and Halls, 1968). One of these is E. coli septicaemia, which occurs in the first week of life and is characterized by invasion of all tissues of the calf by a single serotype of E. coli, followed by fever, collapse, and death (Dam, 1 960). The other is enterotoxic E. coli infection, caused by enterotoxigenic Escherichia coli (ETEC) and occurring in the first few days of life; this form is characterized by proliferation of certain strains of E. coli in the small intestine, causing acute diarrhoea but no systemic invasion. ETEC-strains possess certain virulence factors, one of which is the ability to colonize the small intes-- tine by attaching to the mucosal surface, a phenomenon which is mediated by a pilus attachment or adhesion factor known as the K99 antigen (Orskov et al., Another important virulence factor is the abillity to produce a heat-stable enterotoxin (ST) (Smith and Linggood, 1972). Calves are most susceptible to this disease at the time of colostrum feeding. Colostrum of most cows obviously contains no K99 antibodies capable of preventing colonization of the small intestine by K99-positive E. coli, since even colostrum-fed calves are susceptible to experimental challenge during their first day of life. However, protective colostral immunity can be induced by vaccinating pregnant cows with K99- containing bacterins. Colostral antibodies against K99 antigen will prevent diarrhcea in the calf, apparently by preventing ETEC from colonizing the small intestine in greater numbers. Protection has been demonstrated in vaccination/challenge experiments. Calves nursed by cows previously vaccinated with K99- containing preparations are generally protected

3 against oral inoculation with K99-positive bacteria (Acres et al., 1978; Myers, 1978). Little information is available on the etiologic role of ETEC in Danish calves. The objectives of the present study were to verify the occurrence of infection with ETEC in calves in Denmark and to evaluate the efficacy of K99-bacterins used under field conditions for preventing infection with ETEC in newborn calves. Materials and Methods The material examined consisted of feces samples and autopsy material sent to the laboratory for diagnostic purposes. All samples originating from 1-8-day-old calves were included in the study. Besides, a number of samples from calves older than eight days were examined in order to evaluate the prevalence of ETEC in this age group. Samples of feces and intestinal contents were diluted in 0.85 % saline and plated on blood agar, Drigalski agar, and Minca agar, (Guinee ei al., Autopsy material, i.e., spleen and intestinal lymph nodes, was plated on blood agar and Drigalski agar. From primary plates ETEC-suspected colonies were subcultured on other Minca plates for K99 agglutination test. Identification of K99 antigen was made by slide agglutination with K99 antiserum. Strain B41 (0101:K-, K99), strain B85 (09:K-, K99), and an E. coli K12 (K99 pos.) strain were used for raising K99 antisera in rabbits. Enterotoxigenicity was demonstrated by the infant mice test (Dean et al., 1972). The strains were cultured in trypticase soy broth (BBL). After agitation at 37 C for 18 h the cultures were centrifuged, and the supernatants were tested in infant mice. The enterotoxicity test was regarded as positive if the ratio: weight of intestine/weight of the remaining body, was > The field trial took place in herds in which infection with ETEC had been demonstrated among the calves immediately before the beginning of the trial. Two different K99-containing bacterins were used, namely a 4-strain bacaerin lcoligen, Fort Dodge) and a K99-bacterin (Vicogen, Connaught). During a period of 4-5 months, all pregnant cows were given two injections, at six and three weeks before expected parturition, with one of the two bacterins or with a placebo preparation. Colostral K99 antibody titers were not determined because it was impossible to get samples from the herds regularly. Results A total of 1379 samples from approximately 1000 herds was examined during a period of 24 months, and from 228 (16.5%) of these samples, ETEC was isolated (table 1 Autopsy material accounted for 561 samples, and 818 were feces samples. ETEC was isolated from 153 (27.3%) of the autopsy samples and from 75 (9.2 %) of the feces samples. Infection with ETEC was most frequent in calves of up to 3 day-old, and rare, if present at all, in calves of more than 8 dayold. Table 2 shows the variety of pathogenic agents combined with ETEC in the neonatal diarrhoea complex; in 20 cases the swab submitted was unfit for virological and pa!rasitological examination. In a case of coli septicaemia, E. coli 0-group 88

4 was isolated from all tissues (spleen, liver, kidney, and intestinal lymph nodes) except the intestines, while ETEC and rotavirus were demonstrated in the intestinal contents. Of the vaccinated cows in 14 dairy herds, 296 gave birth to a live calf (or twins) (table 3). In five of the herds no enteric disease developed, either among calves born to vaccinated cows or among calves from the control group, and in nine herds where diarrhoea still occurred the disease was less severe than before the trial started. Eleven per cent of the diarrheic calves died, as compared to 24 % before the trial. The total losses fell from % to 1.7 %. In the trial group the percentage of calves with diarrhoea in the first week of life was 8.2 in the K99 bacterin group, 14.7 in the 4-strain bacterin group, and 21.9 in the placebo group; the difference between the K99 bacterin group and the placebo group is statistically significant. Discussion As in many other countries, enteric diseases are an important economic problem in calf husbandry in Denmark. It is true that a variety of pathogens may be involved in the etiology of calf diarrhoea. In the present study ETEC were found to be widespread all over the country among newborn calves with diarrhcea. The figures in table 1 show that ETEC occurred in 16.5 % of the total samples. Of calves dying 1-5 days old nearly one half (48.5 %) was found to harbour ETEC. The fact that 27.3 % of the samples from carcasses but only 9.2 % of the feces samples were ETEC positive is remarkable. One possible explanation may be that cases of ETEC infection are often so rapidly fatal that examination of samples from living, diarrheic calves is bound to be unsuccessful. Virus (rota-, corona-, or BVD-virus) was found in 54 (26.0 %) of 208 cases in which a complete microbiological examination was possible (table 2). In 151 cases (72.6 %) ETEC alone was found, and only in a very few cases was ETEC found in combination with coli septicaemia, salmonellosis, or Cryptosporidium infection. Rotavirus infection occurs mainly in calves of from four days to several weeks old (de Leeuw et a/., 1980). Snodgrass et al. (1982) found that on simultaneous inoculation of 6 day-old calves with ETEC and rotavirus, ETEC was able to multiply in all of the calves, while in the absence of rotavirus ETEC colonized only one of seven such calves. In

5 the present study, the average age of 43 calves with combined infections with ETEC and virus (rotavirus and/or coronavirus) was 4.2 days, as compared to 2.9 days in 126 calves with ETEC only. So, seemingly, the establishment of ETEC infection in calves older than two days will in most instances require an initial or simultaneous virus infection. In evaluating the effect of vaccination against the naturally occurring disease, it was found that the prevalence of enteric disease in the control group was lower than might be expected on the background of the severe losses from enteric disease in the participating herds before the trial (table 3). This lower prevalence may be due in part, to some herd immunity elicited by immunization of two thirds of the pregnant animals, but perhaps also to improved management, especially with respect to colostrum feeding. EEC seminar on gastro-intestinal diseases in the young pig and calf 1-3 December 1982, INRA CRZV de Theix Beaumont, France. References ACRES S.D., LAING C.J., SAUNDERS J.R., RADOSTITS O.M., Acute undifferentiated neonatal diarrhea in beef calves. I. Occurrence and distribution of infectious agents. Can. J. Comp. Med., 39, I ACRES S.D., ISAACSON R.E., KHACHATOURIANS G., BABIUK L., KAPITANY R.A., Vaccination of cows with purified K99 antigen, K99&dquo; anucleated live E. coli, and whole cell bacterins containing enterotoxigenic E. coli for prevention of enterotoxigenic colibacillosis of calves. Proc. 2nd lnt. Symp. Neonatal Diarrhea, VIDO, Saskatoon, DAM A., Serological 0-grouping of strains of E. coli isolated from cases of coli septicaemia in calves. Nord. Vet. Med., 12, DEAN A.G., CHING C.Y., WILLIAMS R.G., HARDEN L.B., Test for Escherichia coli enterotoxin using infant mice: application in a study of diarrhea in children in Honolulu. J. lnfect. Dis., 125, DE LEEUW P.W., ELLENS D.J., STRAVER P.J., VAN BALKEN J.A.M., MCERMAN A., BAANVINGER T., Rotavirus infections in calves in dairy herds. Res. Vet. Sci., 29, GUINEE P.A.M., JANSEN W.H., AGTERBERG C.M., Detection of the K99 antigen by means of agglutination and immunoelectrophoresis in Escherichia coli isolates from calves and its correlation with enterotoxigenicity. Infect. Immun., 13, MORIN M., LARIVIERE S., LALLIER R., Pathological and microbiological observations made on spontaneous cases of acute neonatal calf diarrhea. Can. J. Comp. Med., 40, MYERS L.L., Passive protection of calves against enteric colibacillosis by vaccination of their dams with capsular and fimbrial K antigens of Escherichia coli. Proc. 2nd Int. Symp. Neonatal Diarrhea, VIDO, Saskatoon, SMITH H.W., HALLS S., The experimental infection of calves with bacteriaemia-producing strains of Escherichia coli: the influence of colostrum. J. Med. Microbiol., 1, SMITH H.W., LINGGOOD M.A., Further observations on Escherichia coli enterotoxins with particular regard to those produced by atypical piglet strains and by calf and lamb strains: the transmissible nature of these enterotoxins and of a K antigen possessed by calf and lamb strains. J. Med. Microbiol., 5, SNODGRASS D.R., SMITH M.L., KRAUHL F.L., Interaction of rotavirus and enterotoxigenic Escherichia coli in the conventionally reared dairy calves. Vet. Microbiol., 7, ORSKOV L, ORSKOV F., SMITH H.W., SOJKA W.J., The establishment of K99, a thermolabile, transmissible Escherichia coli K antigen, previously called akco» possessed by calf and lamb enteropathogenic strains. Acta Pathol. MicrobioL Scand. (B), 83,