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1.
Forty-five calves on four veal calf units were monitored during the first four weeks after their arrival. Faecal samples were collected on alternate days and screened for the presence of rotaviruses, bovine coronavirus, Cryptosporidium oocysts, K99 positive strains of E. coli and Salmonella spp. Rotaviruses and Cryptosporidium were the most commonly detected agents (78% and 60% respectively of the calves). Bovine coronavirus was detected in the faeces of 18% of the calves, whilst K99 positive E. coli was only found in 2 samples from one calf. Salmonella spp. were not isolated from any of the 646 faecal samples examined. Shedding of rotaviruses occurred in a bimodal pattern beginning in the first week of the survey. Cryptosporidium oocysts were detected most frequently in the interval between the two peaks of rotavirus shedding. The presence of rotaviruses or Cryptosporidium oocysts in faeces was not strongly associated with scour, nor were combined infections with these agents or the cases of bovine coronavirus infection. The condition of the calves throughout the survey was generally satisfactory.  相似文献   

2.
Microbiology of calf diarrhoea in southern Britain   总被引：9，自引：0，他引：9  
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.  相似文献   

3.
A case-control study of diarrheal disease in veal calves was conducted over a three month period on a single large veal farm in southern Ontario. One hundred diarrheic calves (cases) were identified by visual examination of their feces. Each case was matched to two nondiarrhetic controls from the same room on the same day, and a fecal sample was obtained from each animal. Fecal consistency of cases and controls was observed daily for one week following sample collection. Control calves which developed diarrhea during that period were excluded from the study. Breed, sex and the date and nature of antimicrobial drugs administered to each calf were recorded. Moisture content of fecal samples was measured by weighing samples before and after oven drying. Samples were screened for verocytotoxigenic Escherichia coli (VTEC) using a Vero cell assay, for enterotoxigenic E. coli (ETEC) using an immunoblot procedure with anti-K99 monoclonal antibodies, and for Salmonella species using modified semi-solid Rappaport-Vassiliadis medium. A latex agglutination test was used to detect rotaviruses, and samples were examined for cryptosporidia using sucrose wet mounts. No VTEC were identified in cases or controls. One calf was positive for Salmonella and three were positive for ETEC. Rotaviruses were detected in four cases and four controls. A significant positive association was found between diarrhea and infection with Cryptosporidium. This study thus provided no evidence of an association between diarrhea and infection with either VTEC, ETEC, Salmonella spp. or rotaviruses in the population examined. On the other hand our results do suggest that Cryptosporidium infection may promote transient diarrheal disease in veal calves in Ontario.  相似文献   

4.
Pathology of calves with diarrhoea in southern Britain   总被引：2，自引：0，他引：2  
Twenty-one moribund calves with diarrhoea were purchased from 11 farms, their faeces examined for enteropathogens and samples of intestinal tissue removed under anaesthesia. Lesions and presence of enteropathogens on the mucosal surface were scored by histological examination of immunostained paraffin sections. Two or more enteropathogens were detected in 19 calves. Cryptosporidium appeared to be the principal cause of diarrhoea in six calves, rotavirus in four, Salmonella typhimurium in two, bacteria adherent to the surface of the large intestine in two, coronavirus in one and K99+ Escherichia coli in one calf. Diarrhoea in four calves was the consequence of mixed infections in which no one enteropathogen appeared to predominate. In one calf no enteropathogen was detected. Diarrhoea was associated with infections and lesions throughout the small and large intestines. The enteropathogens most frequently associated with lesions in the small intestines were rotavirus, coronavirus and cryptosporidium; in the large intestines they were coronavirus and bacteria apparently adherent to the mucosal surface.  相似文献   

5.
Dairy calves less than 1 month of age are commonly infected with Cryptosporidium spp. The objective of the present study was to evaluate the prevalence of Cryptosporidium spp. among dairy calves or=810 oocysts/field. This study shows that Cryptosporidium spp. is one of the causes of calf neonatal diarrhoea in a rural area of Buenos Aires, Argentina. The highest intensity of infection reported for the 相似文献   

6.
Prevalence of enteric pathogens in the feces of healthy beef calves   总被引：5，自引：0，他引：5  
Fecal specimens from 136 healthy beef calves (1 day to 12 weeks of age) were examined for the presence of infectious agents known to cause enteric disease in calves. The calves were selected from 22 herds in which all calves were free of clinically apparent enteric disease. Salmonella sp, enterotoxigenic Escherichia coli, Cryptosporidium, and coronavirus were not detected in any of the calves. Three calves were infected with rotavirus and 1 calf was infected with Yersinia enterocolitica. Campylobacter-like bacteria were isolated from 50 of 130 calves, with 36 of the calves positive for C jejuni. Seemingly, clinically normal calves may be infected more often with enterotoxigenic E coli, Cryptosporidium, coronavirus, or rotavirus in herds in which some calves have enteric disease than in herds free of major enteric disease. Campylobacter jejuni was well adapted to the bovine host and was of similar prevalence in diarrheal and nondiarrheal calves. The K99 positive, nonenterotoxigenic E coli was isolated from the feces of 16 healthy calves. Information in addition to the presence of K99 antigen is useful when diagnosing enterotoxic colibacillosis in calves.  相似文献   

7.
AIM: To determine the occurrence of Cryptosporidium parvum oocysts, Campylobacter spp and Salmonella spp in faecal samples taken from newborn dairy calves on 24 dairy farms in the Manawatu region of New Zealand.

METHODS: A cross-sectional study was conducted during the 2002 calving season. Faecal samples were collected from 185 newborn calves from a convenience sample of 24 dairy farms. The samples were tested microscopically for the presence of C. parvum oocysts, and bacteriologically for the presence of Campylobacter spp and Salmonella spp.

RESULTS: Infections with C. parvum were identified in 33/156 (21.2%) calves from 10 farms. More than 106 oocysts/g (OPG) faeces were detected in calves from four farms. Campylobacter spp were isolated from 58/161 (36%) calves from 18 farms; in particular, C. jejuni subsp jejuni was isolated from 11/161 (6.8%) calves from seven farms. Salmonellae were not detected.

CONCLUSIONS: Despite the short and concentrated calving pattern and the long interval between calving seasons characterising most dairy farms in New Zealand, C. parvum is widespread among calves. Campylobacter spp, especially C. jejuni, rapidly colonise the intestinal tract of newborn calves.

RELEVANCE: This study provided an estimate of the ecological impact of newborn dairy calves with regard to the potentially zoonotic enteric pathogens most frequently isolated from human gastrointestinal infections in New Zealand.  相似文献   

8.
AIM: To determine the occurrence of Cryptosporidium parvum oocysts, Campylobacter spp and Salmonella spp in faecal samples taken from newborn dairy calves on 24 dairy farms in the Manawatu region of New Zealand. METHODS: A cross-sectional study was conducted during the 2002 calving season. Faecal samples were collected from 185 newborn calves from a convenience sample of 24 dairy farms. The samples were tested microscopically for the presence of C. parvum oocysts, and bacteriologically for the presence of Campylobacter spp and Salmonella spp. RESULTS: Infections with C. parvum were identified in 33/156 (21.2%) calves from 10 farms. More than 10(6) oocysts/g (OPG) faeces were detected in calves from four farms. Campylobacter spp were isolated from 58/161 (36%) calves from 18 farms; in particular, C. jejuni subsp jejuni was isolated from 11/161 (6.8%) calves from seven farms. Salmonellae were not detected. CONCLUSIONS: Despite the short and concentrated calving pattern and the long interval between calving seasons characterising most dairy farms in New Zealand, C. parvum is widespread among calves. Campylobacter spp, especially C. jejuni, rapidly colonise the intestinal tract of newborn calves. RELEVANCE: This study provided an estimate of the ecological impact of newborn dairy calves with regard to the potentially zoonotic enteric pathogens most frequently isolated from human gastrointestinal infections in New Zealand.  相似文献   

9.
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10.
This study was carried out to find the importance of Cryptosporidium parvum in diarrhoea of neonatal calves in two types of breeding - suckling and dairy calves - in France. Different agents causing neonatal diarrhoea, E. coli, rotavirus, coronavirus, Salmonella and Cryptosporidium were systematically researched in faeces. 1. Suckling calves: In 40 livestock farms selected for diarrhoea, 311 calves 4 to 10 days old which had diarrhoea for less than 24h or no diarrhoea, were included in the study. A prophylaxis of neonatal diarrhoea had been carried out in 21 of the 40 livestock farms. On D0 (inclusion day), the mean age was 6 days, 82% presented a good initial general condition and 76.2% had a good appetite; 48.6% were diarrhoeic but 91.3% presented no sign of dehydration. Only 6.1% were infected by E. coli K99, 14.3% by rotavirus, 6.8% by coronavirus, 0.3% by Salmonella but 50% excreted C. parvum oocysts. This later percentage increases up to 84% and 86% by D3 and D7, respectively . We note that 16% of the 4-day-old calves on D0 are excreting oocysts and this percentage increases as a function of the age of the calf on D0 to reach 90% to 95% by the age of 8 days. 10 out of 12 dead calves excreted C. parvum oocysts. From D0 to D14 the other pathogen agents show a relative or a decreasing stability. 2. Dairy calves: 382 calves which had diarrhoea for less than 24 h or no diarrhoea, aged 8 to 15 days coming from six industrial livestock farms were included in the study. On D0, 99% of the calves presented a good initial general condition, 99.7% had a good appetite and no calf was dehydrated. At this date (D0), 16.8% of the calves excreted cryptosporidia. This percentage increases up to 23% and 51.8% on D3 and D8, respectively, then decreases to 31.9% on D14. The pressure of the other pathogenicagents remains relatively stable, excepted for rotavirus on D7 (from 9.9% on D0 to 27.2% on D7, then 12.6% on D14) which does not explain the concomitantpeak in diarrhoea because the infection by rotavirus on D7 is more frequent in non-diarrhoeic calves than in diarrhoeic calves. Our results show that Cryptosporidium prevalence is higher in suckling than in dairy calves and C. parvum constitutes actually in both cases the major aetiological agent of neonatal diarrhoea.  相似文献   

11.
To investigate the risk factors for neonatal calf diarrhoea, a cross-sectional study was conducted on 97 New Zealand dairy farms. Faecal specimens from 1283 calves were scored as liquid, semi-solid or solid, and analysed for bovine rotavirus (BRV) and coronavirus (BCV), enterotoxigenic K99+ Escherichia coli (K99), Salmonella spp. and Cryptosporidium parvum. Calf- and farm-level data were collected by means of a questionnaire and the odds of liquid faeces calculated using mixed effects logistic regression models.Among the infectious agents, only C. parvum (odds ratio [OR] = 2.6; 95% confidence interval [CI], 1.3–5.6; P = 0.02), BRV (OR = 2.7; 95% CI, 1.3–5.9; P = 0.01) and co-infection with more than one agent (compared with mono-infection: OR = 2.5; 95% CI, 1.3–4.8; P = 0.01) were associated with increased odds of liquid faeces in calves which were 9 to 21 days old. Housing of calves in open barns so exposing them to the weather was also associated with increased odds of liquid faeces compared with closed barns (OR = 2.1; 95% CI, 1.1–12.2; P = 0.03). Vaccinating cows against calf enteropathogens (OR = 0.2; 95% CI, 0.1–0.9; P = 0.03), administering waste milk (from mastitis and/or containing antibiotics; OR = 0.4; 95% CI, 0.1–0.8; P = 0.01), the sex of calves (females compared to males OR = 0.2, 95% CI, 0.07–0.7; P <0.01), and the use of straw for bedding (OR = 0.2; 95% CI, 0.03–0.9; P = 0.03) decreased the odds of liquid faeces. Conversely, in calves that were 1 to 5 days old, only K99 was associated with liquid faeces (OR = 4.6; 95% CI, 1.2–16.1; P = 0.02). In this age group, the odds of liquid faeces were smaller on farms where females took care of the calves, compared with males (OR = 0.4; 95% CI, 0.01–0.9; P = 0.04).  相似文献   

12.
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13.
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14.
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15.
[目的]为了解河南省犊牛腹泻主要病原流行情况和腹泻病因,有效防控犊牛腹泻,加快养牛业健康发展。[方法]用ELISA方法对从河南省12个地区采集1～6月龄有腹泻临床症状和无腹泻临床症状犊牛粪便样品187份,血液样品305份进行检测。[结果]在305份血液样品中,共检测到病毒性腹泻病毒(BVDV)阳性血样17份;副结核分支杆菌阳性血样13份。187份粪便样品中,检测到微小隐孢子虫阳性样品47份;轮状病毒阳性样品3份;大肠杆菌K99+阳性样品8份;冠状病毒阳性样品5份。[结论]发现犊牛腹泻主要是由病原感染引起的,其中微小隐孢子虫的感染率为较高,同时以单一病原感染为主。  相似文献   

16.
AIM: To investigate the prevalence of Giardia and Cryptosporidium spp in calves born during two spring-calving seasons in a rapidly intensifying dairying region in the South Island; to evaluate potential correlations between the prevalence of the organism and age, characteristics of faeces, and animal-housing practices; and to compare the results with those from established dairying regions in the North Island. METHODS: A longitudinal study was conducted in 2005 and 2006 on 10 dairy farms located in the Otago region, South Island, New Zealand. A total of 1,190 faecal samples were collected from calves 1-7 weeks old. Direct immunofluorescent microscopy was used to screen the faecal samples for Giardia cysts and Cryptosporidium oocysts. The prevalence of Giardia and Cryptosporidium spp detected in calves in Otago was compared with that previously measured in calves from dairying regions in the Waikato and Manawatu, in the North Island . RESULTS: On average, Giardia and Cryptosporidium spp were detected in 31% and 2.6% of all samples, respectively. The prevalence of Giardia spp cysts in faeces was higher in calves >or=3 weeks of age in 2005 (por=2 weeks of age in 2006 (p=0.07) than in younger calves. No age-related pattern was observed for Cryptosporidium spp in either year. No correlations were evident between characteristics of faeces or animal housing practices and the prevalence of either organism, which did not differ between the two dairy farming regions. CONCLUSIONS: Prevalence rates of Giardia and Cryptosporidium spp in calves 1-7 weeks old did not differ between the two geographical regions, nor did the regions' distinct climate conditions appear to influence the prevalence of either pathogen. Considering data from both years together, the presence of Giardia spp cysts in faeces appeared to increase in the first week or two after birth, so that, on average, 30-40% of animals from 3-6 weeks of age were affected. CLINICAL RELEVANCE: This is the first study to report the prevalence of Giardia and Cryptosporidium spp in dairy calves in the South Island of New Zealand.  相似文献   

17.
This work was conducted to investigate calf-level factors that influence the risk of neonatal diarrhea and shedding of Cryptosporidium parvum oocysts in calves, on dairy farms in Ontario with histories of calf diarrhea or cryptosporidiosis. Fecal samples were collected weekly for 4 weeks from each of 1045 calves under 30 days of age on 11 dairy farms in south-western Ontario during the summer of 2003 and the winter of 2004. A questionnaire designed to gather information on calf-level management factors was administered on farm for each calf in the study. Samples were examined for C. parvum oocysts by microscopy, and a subset of specimens was also tested for enterotoxigenic Escherichia coli, Salmonella, bovine rotavirus and bovine coronavirus. The consistency of each sample was scored and recorded at the time of collection in order to assess the presence or absence of diarrhea. In addition, a blood sample was taken from each calf upon enrollment in the study, for assessment of maternal antibody transfer and for polymerase chain reaction testing for persistent bovine viral diarrhea virus infection. Using the GLLAMM function in Stata 9.0, multilevel regression techniques were employed to investigate associations between management practices and the risk of C. parvum shedding or diarrhea. C. parvum oocysts were detected in the feces of 78% of the 919 calves from which all four fecal samples had been collected. Furthermore, 73% of the 846 calves for which all four fecal consistency scores had been recorded were diarrheic at the time of collection of at least one sample. Significant predictors of the calf-level risk of C. parvum shedding included the use of calf diarrhea prophylaxis in pregnant cows, and the type of maternity facilities in which the calves were born. Factors associated with an increased risk of diarrhea were leaving the calf with the dam for more than an hour after birth, and the birth of a calf in the summer as opposed to winter. Calves shedding C. parvum oocysts had 5.3 (95% CI 4.4, 6.4) times the odds of diarrhea than non-shedding calves, controlling for other factors included in the final multivariable model. Furthermore, infected calves shedding more than 2.2 x 10(5) oocysts per gram of feces were more likely to scour than infected calves shedding lower numbers of oocysts (OR= 6.1, 95% CI 4.8, 7.8). The odds of diarrhea in calves shedding oocysts that had been allowed to remain with their dams for more than an hour were higher than the odds of diarrhea in shedding calves that had been separated from their dams within an hour after birth.  相似文献   

18.
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.  相似文献   

19.
Cryptosporidium parvum is a protozoan parasite causing diarrhoea in young calves. This cross-sectional study was performed to estimate the prevalence of Cryptosporidium infected herds in a sample of Swedish dairy herds and to identify potential risk factors associated with shedding of oocysts. Fifty dairy herds, selected by stratified random sampling, were included. The herds were visited once during the indoor seasons of 2005–2006 and 2006–2007. Faecal samples were collected from 10 calves, 10 young stock and 5 cows in each herd. Clinical observations of sampled animals and environmental status were recorded, and farmers were interviewed about management procedures. Faecal samples were cleaned by sodium chloride flotation and detection of oocysts was made by epifluorescence microscopy. Cryptosporidium parvum-like oocysts were found in 96% of the herds. Prevalence was 52% in calves, 29% in young stock and 5.6% in cows. Three two-day-old calves shed oocysts. Cryptosporidium andersoni was found in seven animals from four different herds. Factors associated with prevalence of shedders among sampled animals in a herd were age at weaning, cleaning of single calf pens, placing of young stock, system for moving young stock, and year of sampling. Factors associated with shedding in calves were age, placing of young stock, routines for moving young stock and time calf stays with the cow. The only significant factor in young stock was age. In cows, number of calves in the herd and type of farming (organic vs. conventional) affected shedding.  相似文献   

20.
The disinfection of a farm with Dikonit (active substance: sodium dichlorocyanuran) exerted no significant influence on the course of the spreading of cryptosporidiosis infections in newborn calves. The oocysts of Cryptosporidium sp., isolated from the faeces of a spontaneously infected calf and left in a 2.5% disinfecting solution of Dikonit under laboratory conditions for four hours, did not lose their viability. Laboratory mice experimentally infected with these "disinfected" oocysts, began to produce oocysts of Cryptosporidium sp. the sixth day from infection. The findings of different developmental stages of this protozoan obtained during the histological examination of the intestinal tissue of test mice are also considered as evidence of successful experimental infection. The cryptosporidium-free period which lasted only 14 days from disinfection was mainly due to thorough mechanical cleaning of the area where the calves were kept after birth. This is also proved by the results of the examination of old residues of calf faeces scraped from the floors: only individual individual oocysts of Cryptosporidium sp. were found in these samples.  相似文献   

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