Effect of vaccination of the dam on rotavirus infection in young calves

Vaccination of cows with a combined, inactivated, adjuvanted rotavirus and Escherichia coli vaccine resulted in increased neutralising antibody titres to rotavirus in serum and colostral whey. Evidence was obtained that vaccination resulted in a decreased incidence of rotavirus shedding and of abnormal faeces or diarrhoea in young calves fed colostrum and milk from the vaccinated dams. The E coli component of the vaccine was not evaluated because no natural challenge was evident.     

Aetiology of diarrhoea in young calves

Faeces samples were collected from 302 untreated calves on the day of onset of diarrhoea and from 49 healthy calves at 32 farms experiencing outbreaks of diarrhoea. At least four diarrhoeic calves were sampled on each farm, and samples were examined for rotavirus, coronavirus, cryptosporidium, enterotoxigenic Escherichia coli and Salmonella species. Although all these enteropathogens were excreted more frequently by the diarrhoeic than by the healthy calves, the difference was significant overall only for rotavirus. Rotavirus was excreted by 18 per cent of healthy calves, coronavirus by 4 per cent, cryptosporidium by 14 per cent, and no enterotoxigenic E coli or Salmonella species were detected. The most common enteropathogen in diarrhoeic calves was rotavirus, which was excreted by more than half the diarrhoeic calves on 18 farms. Coronavirus was excreted at a similar high prevalence on one farm, cryptosporidium on five farms and enterotoxigenic E coli on three farms. Concurrent infection with two or more microorganisms occurred in 15 per cent of diarrhoeic calves. There was no difference in the isolation rate of campylobacters between diarrhoeic and healthy calves.     

Longitudinal survey of rotavirus infection in calves

A longitudinal survey of rotavirus infection in heifer calves was carried out on a closed Friesian dairy herd over two successive calving seasons. Rotavirus was detected by electron microscopy in the faeces of 45 of 57 (79 per cent) calves examined. On average the virus was first detected at 6.1 days of age. Clinically the disease associated with rotavirus infection was of mild to moderate severity. Only one infected calf required intravenous fluid therapy. Diarrhoea or excretion of abnormal faeces was associated with rotavirus infection in 58 per cent of infected calves, while in the remaining 42 per cent infection was subclinical. The cycle of rotavirus infection was broken by thorough cleansing and disinfection of the calf house.     

Duration of immunity and efficacy of an oil emulsion Escherichia coli bacterin in cattle

An oil emulsion Escherichia coli bacterin administered in 1- and 2-dose vaccination regimens was evaluated in beef cattle. Serologic responses to the K99 pilus antigen were monitored, and suckling offspring from vaccinated and nonvaccinated cows were inoculated with virulent, K99-positive, enterotoxigenic Escherichia coli. The degree of protection and duration of immunity conferred were determined in 2 respective studies. In the first study (study A), titers of pregnant cattle were determined from time of vaccination through calving (a 6- to 20-week period). Titers of 24 cows vaccinated with a single 2-ml dose of bacterin were compared with those of 24 cows given a 2-dose regimen and with those of 23 nonvaccinated cattle (contemporary controls). Inoculum consisting of 1.2 X 10(12) viable enterotoxigenic E coli/dose administered to nursing calves from these dams yielded 0% mortality (0 deaths/20 calves) in calves from 1-dose vaccinates, 6% mortality (1 death/18 calves) in calves from 2-dose vaccinates, and 37% mortality (7 deaths/19 calves) in calves from nonvaccinated dams. Study B was an extended evaluation conducted in cattle that were kept in the study up to 87 weeks from initial vaccination until calving. Serologic titers to the K99 pilus antigen were compared in 1-dose, 2-dose, and nonvaccinated cattle in groups of 8, 6, and 6, respectively. Calves from these dams were inoculated with 8.1 X 10(11) viable enterotoxigenic E coli/dose, which resulted in 0% mortality (0 deaths/5 calves) in calves from 1-dose vaccinates, 0% mortality (0 deaths/5 calves) in calves from 2-dose vaccinates, and 80% mortality (5 deaths/6 calves) in calves from nonvaccinated dams.     

The studies on the aetiology of diarrhoea in neonatal calves and determination of virulence gene markers of Escherichia coli strains by multiplex PCR

The purpose of this study was to determine aetiological agents of diarrhoea in neonatal calves and to investigate virulence gene markers of Escherichia coli strains isolated from calves by multiplex polymerase chain reaction (PCR). Eighty-two diarrhoeic calves and 18 healthy calves were used as subjects. Faeces were taken from the rectums of all the calves and were subjected to bacterial culture. Antigen enzyme-linked immunosorbent assay (ELISA) was performed to detect rotavirus, coronavirus and E. coli K99 in faeces of all the calves. A multiplex PCR was used to characterize E. coli strains in all the calves. Escherichia coli was isolated from 37 faeces samples, Enterococcus ssp. was isolated from 22 faeces samples and Salmonella was isolated from one faeces sample in diarrhoeic calves. Furthermore, only E. coli was isolated from all 18 faeces samples of healthy calves. Of the 37 E. coli isolated from diarrhoeic calves, K99 (18.9%), F41 (18.9%), heat-stable enterotoxin a (STa) (18.9%), Shiga toxin 1 (Stx1; 13.5%) and Shiga toxin 2 (Stx2; 5.4%) and intimin (8.1%) genes were identified by multiplex PCR. Of the 18 E. coli isolated from healthy calves, K99 (16.6%) and intimin (55.5%) genes were identified by PCR. A total of 15 rotavirus, 11 coronavirus and 11 E. coli K99 were detected in diarrhoeic calves by the antigen ELISA. As a result, this study shows that rotavirus, coronavirus, E. coli and Enterococcus ssp. were determined to play a role in the aetiology of diarrhoea in the neonatal calves. K99, F41, STa, Stx1 and Stx2 were found as the most common virulence gene markers of E. coli strains isolated from calves with diarrhoea. Multiplex PCR may be useful for characterization of E. coli isolated from calves.     

Reduction in morbidity due to diarrhea in nursing beef calves by use of an inactivated oil-adjuvanted rotavirus-Escherichia coli vaccine in the dam.

An outbreak of neonatal diarrhea occurred among beef calves (2000 animals) from one large Argentinian farm in 1985. Rotavirus was detected in 78% (106/136) and enterotoxigenic Escherichia coli in 1.5% of the samples (2/136) obtained from sick calves. In comparison rotavirus was identified in only 1.6% (1/63) of the samples from clinically healthy calves. The rotavirus strain responsible for the outbreak was characterized as serotype 6 belonging to group A. In the following three years the protective capacity of a combined rotavirus-E. coli inactivated vaccine administered to the dams during the last third of the gestation period was evaluated on this farm by comparison of morbidity due to diarrhea in calves from vaccinated vs. placebo cows within the same year. The morbidity due to diarrhea among calves from dams in the vaccinated and placebo groups was 34% and 77%, respectively in 1986; 23% and 47% in 1987, and 15% and 34%, in 1988. In 1987 morbidity of diarrhea in calves born from vaccinated heifers was 54% and 74% in calves from placebo heifers. In 1988 morbidity from diarrhea was 41% and 54%, respectively among calves in these two groups. In all experiments, calves from heifers showed significantly greater morbidity than calves from cows. Differences in diarrhea morbidity between the vaccinated and placebo groups were statistically significant (P less than 0.05). Additional studies showed that the diarrhea had a significant influence (P less than 0.05) on the average live weight of the calves at weaning (5 to 7 months) with an average weight loss of 7.8 kg per calf among the calves affected with diarrhea.     

Serological, colostral and milk responses of cows vaccinated with a single dose of a combined vaccine against rotavirus, coronavirus and Escherichia coli F5 (K99)

Twenty-five Ayrshire/Friesian cows were vaccinated once with a new combined vaccine against rotavirus, coronavirus and Escherichia coli F5 (K99) or given a saline placebo 31 days before the first expected calving date. Blood samples were taken from the cows at intervals from vaccination until seven days after calving and from their calves up to 28 days after birth, and colostrum and milk samples were collected from the cows at intervals for 28 days after calving. There was a significant increase in the mean specific antibody titre against all three antigens in the serum of the vaccinated animals (even in the presence of pre-existing antibody) which was accompanied by increased levels of protective antibodies to rotavirus, coronavirus and E coli F5 (K99) in their colostrum and milk for at least 28 days.     

Microbiology of calf diarrhoea in southern Britain

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.     

Intestinal changes associated with rotavirus and enterotoxigenic Escherichia coli infection in calves

Newborn calves inoculated with rotavirus, enterotoxigenic Escherichia coli (ETEC) serotype 020:K' x 106':K99:HNM, either alone or in combination, became depressed, anorectic, diarrhoeic and dehydrated. ETEC did not adhere to the intestine although there was extensive proliferation in the lumen. Only slight mucosal changes were induced by ETEC and the activity of membrane bound lactase remained normal. More severe mucosal damage and a decrease in lactase activity were found in newborn calves inoculated with either rotavirus or rotavirus and ETEC in combination. The most severe clinical illness was found in calves inoculated with both rotavirus and ETEC. Calves inoculated at 1 week of age with either rotavirus or ETEC remained clinically normal. Rotavirus infection produced slight mucosal changes and a reduction of lactase activity. In contrast, colostrum-fed or suckling calves up to 2 weeks old inoculated with both rotavirus and ETEC became clinically affected, showed severe mucosal damage and decreased lactase activity. There was no bacterial adhesion to the intestinal mucosa as observed by immunofluorescent labelling and light microscopy.     

Prevalence of four enteropathogens in the faeces of young diarrhoeic dairy calves in Switzerland

The prevalences of Cryptosporidium parvum, rotavirus, bovine coronavirus (bcv), and enterotoxigenic Escherichia coli (E coli k99) were determined in diarrhoeic dairy calves aged one to 21 days on 71 dairy farms in western Switzerland during the winter of 2005 to 2006. Faecal samples from 147 untreated calves suffering from acute diarrhoea were analysed by standardised diagnostic methods, and the immunoglobulin status of each calf was evaluated. The prevalences of C parvum, rotavirus, bcv and E coli k99 were 55.0 per cent, 58.7 per cent, 7.8 per cent and 5.5 per cent, respectively. The proportions of herds positive for the respective pathogens among the herds with diarrhoeic calves were 41.7 per cent, 52.1 per cent, 2.1 per cent and 2.1 per cent. The immunoglobulin concentration in the serum of 90.5 per cent of the diarrhoeic calves was below 8 g/l.     

Prevalence of enterotoxigenic Escherichia coli in calves in Scotland and northern England

Eighty-eight of 1529 (5.7 per cent) Escherichia coli isolates from diarrhoeic and clinically normal calves in Scotland and northern England were found to possess the K99 pilus antigen (K99+). There was complete correlation between possession of K99 antigen, heat stable enterotoxin production and ability to dilate intestinal loops. The diagnosis of calf enterotoxigenic E coli infections may therefore be based on the detection of K99 antigen alone. Enterotoxigenic E coli was isolated from 23 of 306 (7.5 per cent) diarrhoeic calves from eight of 70 (11.4 per cent) farms and was not isolated from clinically normal calves. Infected calves were between one and three days old. A survey by an enzyme-linked immunosorbent assay found 3.0 per cent and 3.9 per cent of sera from calves and cows respectively to contain antibodies to K99 antigen. The prevalence of other enteropathogenic organisms in calf faeces is also discussed.     

Diarrhoea in dairy calves reduced by feeding colostrum from cows vaccinated with rotavirus

Forty-two dairy calves remained with their dams for two days after birth, and then were removed to a calf rearing shed. Calves were allocated to three groups for the next 14 days, and received twice daily either whole milk, whole milk with a 10 per cent supplement of pooled normal bovine colostrum or whole milk with 10 per cent supplement of colostrum from cows vaccinated with rotavirus. A natural outbreak of diarrhoea occurred, affecting 28 of the 42 calves. Feeding immune colostrum delayed the onset of diarrhoea, and reduced its incidence, duration and severity. Live weight gains were consequently improved. The group fed normal colostrum had diarrhoea intermediate in severity between that of control calves and those fed immune colostrum. The aetiology of the diarrhoea was complex, with calves excreting rotavirus, enteropathogenic Escherichia coli and cryptosporidia.     

Evaluation of a combined rotavirus and enterotoxigenic Escherichia coli vaccine in cattle

A vaccine of rotavirus and K99 antigen from enterotoxigenic Escherichia coli was emulsified in oil adjuvant and administered intramuscularly to pregnant cows. Calves born to and reared on vaccinated dams were protected against experimental rotavirus infection at five days old when compared with calves from unvaccinated control cows. Field trials of the vaccine were carried out in 40 commercial herds, in which half the cows in each herd were selected at random for vaccination and half were left unvaccinated. In 31 herds (2641 cows) there was no significant diarrhoea problem (less than 10 per cent morbidity); these herds were excluded from further analysis. The nine remaining herds did experience a calf diarrhoea problem of greater than 10 per cent morbidity, but on four farms the disease was associated with cryptosporidiosis and on a fifth no enteropathogens were detected; these five farms (461 cows) were also excluded from further analysis. Of the remaining four herds, two beef suckler herds (105 cows) had concurrent rotavirus and cryptosporidial infections, and vaccination was associated with a decreased excretion of rotavirus but not with a decreased incidence of diarrhoea. In the other two dairy herds (68 cows) with prevaccination rotavirus problems, there was a significantly decreased incidence of diarrhoea in calves born to vaccinated cows. No natural field challenge of enterotoxigenic E coli was encountered on any of the trial farms.     

Intestinal antibody response after vaccination and infection with rotavirus of calves fed colostrum with or without rotavirus antibody

The intestinal and systemic antibody response of calves vaccinated and/or challenged with rotavirus was studied employing isotype-specific ELISAs for the detection of IgG1, IgG2, IgM and IgA antibodies to rotavirus. Monoclonal antibodies to bovine immunoglobulin isotypes of proven specificity were used as conjugated or catching antibody. Five days after oral inoculation (dpi) of a 5-day-old gnotobiotic calf with rotavirus, IgM rotavirus antibodies were excreted in faeces, followed 5 days later by IgA rotavirus antibodies. The increase in IgM rotavirus antibody titre coincided with the inability to detect further rotavirus excretion. Faeces IgM and IgA rotavirus antibody titres fell to low levels within 3 weeks post infection. IgG1 and IgG2 rotavirus antibodies were not detected in faecal samples. In serum, antibodies to rotavirus of all four isotypes were detected, starting with IgM at 5 dpi. Two SPF-calves, which were fed colostrum free of rotavirus antibodies, were vaccinated with a modified live rotavirus vaccine and challenged with virulent rotavirus 6 days later. Upon vaccination, the calves showed an antibody response similar to the response of the infected gnotobiotic calf. Intestinal IgM rotavirus antibodies were excreted before or on the day of challenge and appeared to be associated with protection against challenge infection with virulent virus and rotavirus-induced diarrhoea. In 3 control calves, which were challenged only, the antibody patterns also resembled that of the gnotobiotic calf and again the appearance of IgM rotavirus antibodies coincided with the end of the rotavirus detection period. Two other groups of 3 SPF-calves were treated similarly, but the calves were fed colostrum with rotavirus antibodies during the first 48 h of life. These calves excreted passively acquired IgG1 and IgG2 rotavirus antibodies in their faeces from 2 to 6 days after birth. After vaccination, no IgM or IgA antibody activity in serum or faeces was detectable. Upon challenge, all calves developed diarrhoea and excreted rotavirus. Seven to 10 days after challenge low levels of IgM rotavirus antibody were detected for a short period. These data indicate that the intestinal antibody response of young calves to an enteric viral infection is associated with the excretion of IgM antibodies, immediately followed by IgA antibodies. This response is absent or diminished in calves with passively acquired specific antibodies which may explain the failure to induce a protective intestinal immune response by oral vaccination with modified live rotavirus of calves fed colostrum containing rotavirus antibodies.     

A field trial to evaluate the efficacy of a combined rotavirus-coronavirus/Escherichia coli vaccine in dairy cattle.

A field trial was designed to determine the efficacy of a combination rotavirus-coronavirus/Escherichia coli vaccine on dairy farms in southwestern Ontario. In Part A of the trial, 321 cows on 15 farms were randomly assigned to either vaccination or placebo groups. On eight farms, 50% of the dams were vaccinated, while on the other seven farms, 80% of the dams were vaccinated. In Part B of the trial, 26 farms were randomly assigned to either a total vaccination program or to no vaccination program. Mortality, disease occurrence and weight gains were recorded on all calves for the first two weeks of life. In Part A, 23.5% of all calves were treated in the first two weeks of life, 20.9% were treated specifically for scours and 3.6% of live-born calves died. Enteropathogenic E. coli was identified on 13 of the 15 farms, rotavirus on 11 and coronavirus on ten. At least one of the three potential pathogens was found on every farm. There were no significant differences between calves from placebo-treated and vaccine-treated dams with regard to the proportion treated for all diseases, or for scours, or the proportion which died. Neither were there differences in days to first treatment for all diseases (seven days on average), days to first scour (6.7 days), duration of treatments (3.9 days for all diseases, 3.7 days for scours), or estimated weight gains (0.5 kg/day to 14 days). These results were not altered when the presence or absence of enteropathogenic E. coli, rotavirus or coronavirus on the premises was accounted for.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pathological changes in the small intestine of neonatal calves naturally infected with reo-like virus (rotavirus).

Nine calves, of which six had been challenged with an enteropathogenic strain of Escherichia coli, were found to be naturally infected with rotavirus. Rotavirus was recovered from the faeces of six calves and rotavirus antigen was detected in the intestinal mucosa of all calves. Stunting and fusion of villi were seen principally in the proximal and middle small intestine, where rotavirus antigen was detected by immunofluorescence. Typical lesions of enteric colibacillosis were found in the distal ileum of the challenged calves, associated with adhesion of the challenge strain of E coli to the mucosa. All samples were removed from the intestine under general anaesthesia and denudation of villi was not observed. However, following exsanguination and resampling at the same site in the small intestine of one calf, denudation was a constant feature.     

Studies on neonatal calf diarrhoea caused by rotavirus: transmission of the disease and attempted vaccination of colostrum-deprived calves

Mild to severe scouring could be produced in colostrum-deprived calves with tissue culture-adapted rotavirus and feacal material from field cases of calf diarrhoea. The feaces of experimentally infected calves contained rotavirus for at least 3 days. Pathogenic bacteria were presented in one calf only and this calf also showed the most severe gastroenteritis. Eight calves were vaccinated with a live rotaviral calf diarrhoea vaccine and subsequently challenged with infective rotavirus. Mild scouring was observed after vaccination, but the calves remained normal after challenge. Rotavirus particles were detectable in the faeces for a few days after vaccination and challenge.     

Rotavirus infection in calves in Bangladesh

Faecal samples from 434 calves under 1 year of age (307 diarrhoeal and 127 normal) were collected from three dairy farms and one village in selected areas of Bangladesh. The samples were tested by an enzyme-linked immunosorbent assay (ELISA) to detect the presence of rotavirus antigen. Of 402 dairy calves tested, 28 (7.0%) were positive, of which 21 (7.2%) were from diarrhoeic calves and 7 (6.3%) from non-diarrhoeic calves. Rotavirus infection varied from farm to farm (2.7–9.2%) and there was no positive response from any of the 32 village calves. Rotavirus was most commonly found in calves of 1 week of age or less (up to 22.2% in one group) but was not found in any calves later than 6 months of age. More than 80% of rotavirus-positive samples from diarrhoeic calves exhibited a titre of 128 or more (geometric mean 345±4.5), whereas non-diarrhoeal calves had titres less than or equal to 128 (geometric mean=29±1.9), suggesting that rotavirus infection in calves in Bangladesh was mostly associated with diarrhoea.     

Cryptosporidium parvum and Giardia intestinalis in calf diarrhoea in Sweden

The objective of this study conducted in 75 herds was to investigate the presence and significance of Criptosporidium parvum and Giardia intestinalis in Swedish dairy calves in comparison with rotavirus, coronavirus and Escherichia coli K99+. The farmers were asked to collect faecal samples from each heifer calf that had diarrhoea between birth and 90 days of age, and also from a healthy calf of the same age. In total, 270 samples were collected and analysed. C. parvum, either alone or together with G. intestinalis and/or rotavirus, was detected in 16 (11%) and 6 (5%) of the samples from diarrhoeic and healthy calves, respectively. Even though a higher proportion of diarrhoeic calves shed C. parvum, the difference between the groups was not statistically significant (p = 0.067), possibly due to the low number of positive samples. G. intestinalis was found in 42 (29%) of the diarrhoea samples and in 29 (23%) of the samples from healthy calves. Rotavirus and coronavirus were demonstrated in 24% and 3% of the diarrhoea samples, respectively, whereas E. coli K99+ was only found in samples from 2 healthy calves. C. parvum and G. intestinalis were found in samples from calves 7 to 84 days of age and during all seasons. The results confirm that C. parvum is present in Swedish dairy herds and might have clinical significance. G. intestinalis was the most common agent found but the importance of this parasite remains unclear. Both parasites have suggested zoonotic potential and thus warrant further attention. In addition, rotavirus is a major pathogen in neonatal enteritis in Sweden, whereas coronavirus and E. coli K99+ seem to be of less importance.     

The prevalence of enteric pathogens in diarrhoeic thoroughbred foals in Britain and Ireland.

A survey of 77 normal and 326 diarrhoeic foals in Britain and Ireland from 1987 to 1989 revealed a significantly higher prevalence of Group A rotaviruses and Aeromonas hydrophila in diarrhoeic foals. The prevalence of cryptosporidia, potentially pathogenic Escherichia coli, Yersinia enterocolitica and Clostridium perfringens was similar in normal or diarrhoeic foals. Rotaviruses had a similar prevalence in all age groups of scouring foals up to three months of age, with an overall prevalence of 37 per cent among diarrhoeic foals. The number of cases of diarrhoea varied considerably from year to year, but in all three years of the survey rotavirus was a significant pathogen. A comparison of diagnostic tests for rotavirus in the faeces showed electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) to have similar sensitivity. The Rotazyme ELISA test kit was found to have the same sensitivity as a combination of EM and PAGE. A. hydrophila had an overall prevalence of 9 per cent among diarrhoeic foals, although its prevalence was higher in some age groups. A. hydrophila has not been established previously as a significant enteric pathogen in foals. Other putative pathogens found at very low prevalence were coronavirus, the putative picobirnavirus, Campylobacter spp. and Salmonella spp. No evidence was found of synergistic effects between rotavirus, cryptosporidia and potentially pathogenic E. coli. Neither coccidia nor non-Group A rotaviruses were found in any of the samples examined.