Prevalence of Cryptosporidium parvum in mithuns (Bos frontalis) from India

Systematic examination of faecal samples from mithuns maintained at the National Research Centre on Mithun, Indian Council of Agricultural Research (ICAR), Nagaland, India and mithuns found in free-ranging condition of Nagaland, by using a commercially available enzyme-linked immunosorbent assay kit, revealed that the overall prevalence of Cryptosporidium parvum in mithun was 56% (95% CI=48-64). Highest (prevalence rate=81, 95% CI=67-95) prevalence was found in mithuns of 1-6 months of age and lowest (prevalence rate=42, 95% CI=31-53) in mithuns above 2 years of age. The prevalence was found to be higher (94%) in diarrhoeic animals in comparison to non-diarrhoeic group (51%). No statistically significant difference was observed between male (prevalence rate=61, 95% CI=48-74) and female (prevalence rate=53, 95% CI=43-63) prevalences. The prevalence was found to be higher (prevalence rate=64, 95% CI=55-73) in mithuns kept in semi-intensive system than mithuns found in free-ranging condition (prevalence rate=40, 95% CI=27-53). The risk factor that may play a pivotal role in the epidemiology of cryptosporidiosis in mithun is also discussed in brief. The zoonotic implication of the disease is also discussed. This is probably the first report on prevalence of Cryptosporidium parvum in mithun.     

Prevalence and epidemiology of selected enteric infections of livestock in Trinidad

In a study of diarrhoeic and non-diarrhoeic livestock (cattle, pigs and sheep) from 50 farms in Trinidad, the prevalence of bacterial (Campylobacter, Salmonella, Yersinia and Escherichia coli), parasitic (coccidia, Cryptosporidium and enteric helminths) and viral (rotavirus) enteropathogens in faeces or rectal swabs was determined. Occurrence of the enteropathogens was tested for association with age, health status, animal species and mixed infections.

Of 423 diarrhoeic animals tested, Salmonella was isolated from 21 (5.0%), Campylobacter from 191 (45.2%) and Yersinia from three (0.7%), while the corresponding prevalence from 270 non-diarrhoeic controls was eight (3.0%) (χ² 1.19, P = 0.28), 119 (44.1%) (χ² 0.04, P = 0.85) and four (1.5%) (χ² 0.8, P = 0.39), respectively. Verocytotoxigenic E. coli and heat-labile toxin-producing E. coli were isolated from 51 (13.7%) and five (1.3%), respectively, of 373 diarrhoeic animals but the corresponding prevalence from 258 non-diarrhoeic animals was 39 (15.1%) (χ² 0.15, P = 0.7) and five (1.9%) (χ² 0.07, P = 0.8), respectively. Cryptosporidium oocytes were detected in 67 (16.5%) of 406 diarrhoeic animals and from 31 (12.1%) of 257 non-diarrhoeic animals (χ² 2.13, P = 0.15). For 147 diarrhoeic animals tested for coccidia, 64 (43.5%) were positive compared with 34 (37.8%) of 90 non-diarrhoeic animals (χ² 0.54, P = 0.49).

The prevalence of rotavirus infection was significantly (P 0.001, χ² 37.8) higher in diarrhoeic animals (39.9%, 112 of 281) than in non-diarrhoeic animals (13.4%, 26 of 194).     

Prevalence and analysis of potential risk factors for Cryptosporidium parvum infection in lambs in Zaragoza (northeastern Spain)

An epidemiologic study was carried out to investigate the prevalence of and to identify factors associated with the risk of Cryptosporidium infection in sheep in Zaragoza (northeastern Spain). Faecal samples from 583 lambs aged from 1 day to 3 months and 205 ewes older than 1 year were collected at 89 farms in the two regions of the province of Zaragoza with the highest sheep population (Zaragoza and Ejea de los Caballeros). In every sheep farm, data of the factors potentially associated with the likelihood of C. parvum infection were analysed: geographical location, season, size of herd, number of lambs in the herd at sampling time, lambing period, cleaning of lambing area and presence of diarrhoeic lambs in the farm. C. parvum oocysts were identified by using the Ziehl-Neelsen technique in 344 lambs (59%) from 75 farms (84.4%). Infected lambs ranged from less than 7 days to 90 days of age, although the percentage of animals shedding oocysts peaked at 8-14 days of age (76.2%). Statistical analysis showed that infection rates were significantly higher in lambs aged between 1 and 21 days (66.4%) than in those aged between 22 and 90 days (23%) (P<0.0001, chi(2)). Analysis of correlation between excretion of oocysts and diarrhoea revealed a relationship in all age groups and the probability of presenting diarrhoea was significantly higher for lambs shedding oocysts (86.3%) than for those which did not excrete the parasite (32.2%) (P<0.0001, chi(2)). Similarly, cryptosporidial infection rates were significantly higher in diarrhoeic (79.4%) than in non-diarrhoeic lambs (22.4%). Furthermore, infection intensity was correlated with the presence of clinical symptoms. Presence of diarrhoeic lambs in the farm was the only factor significantly associated with an increased risk of infection since the percentage of herds testing positive was significantly higher in farms with diarrhoeic lambs (91.3%) than in those without cases of neonatal diarrhoea (12.5%) (P<0.0001, chi(2)). Factors associated with a decreased risk of C. parvum infection in lambs included low numbers of lambs in the farm and cleaning of the lambing area. Additionally, lambs 8-14 days of age were less likely to be infected at the first lambing period and in spring/autumn. Cryptosporidial infection was also detected in 16 ewes (7.8%) which excreted few oocysts and without diarrhoea.     

Cryptosporidiosis in buffalo calves (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>): Prevalence and potential risk factors

The objective of the present study was to describe the prevalence and risk factors associated with cryptosporidiosis in buffalo calves in Middle Egypt. During one year, 458 fecal samples were collected from buffalo calves less than 3 month age in 55 small scale herds and examined for the presence of Cryptosporidium oocysts. Data describing age, gender, season, and herd management practices were gathered to assess potential risk factors. Fecal examination showed that 14.19% of the examined calves were positive for Cryptosporidium spp. Calves at 1-15 days were at the highest risk (P < 0.001), and a significant relationship between season and infection (P < 0.05) was recorded. A significant association between infection and hygiene (P < 0.001), type of floor (P < 0.01) and source of water (P < 0.01) was also recorded. Statistical analysis concerning the clinical signs and fecal characteristics revealed a significant association with fecal consistency (P < 0.001), presence of blood (P < 0.01) and mucous (P < 0.01). Moreover, a significant association was found between infection and the desire for suckling (P < 0.05) and tenesmus (P < 0.05). The results of the present study demonstrated the strong relation between infections by Cryptosporidium spp. and diarrhea in buffalo calves.     

Age-related and housing-dependence of Cryptosporidium infection of calves from dairy and beef herds in South Bohemia, Czech Republic

Data of the prevalence, age-related and housing-dependence of naturally acquired cryptosporidiosis on 11 dairy and 11 beef farms in South Bohemia (Czech Republic) were collected. The farms were visited over four consecutive years (from 2002 to 2005). The prevalence of Cryptosporidium in pre-weaned (animals until second month of age) and post-weaned (animals from the third month of age) calves was determined. A total of 7001 faecal samples were collected, concentrated by Sheather's floatation method and stained by aniline-carbol-methyl violet. All samples were examined by light microscopy. Cryptosporidium parvum and C. andersoni oocysts were differentiated on morphological criteria. Of the 7021 specimens, 1814 (25.8%) were positive for Cryptosporidium oocysts; 561 samples (8%) for C. parvum and 1253 (17.8%) for C. andersoni. Pre-weaned dairy calves had higher infection levels of C. parvum than pre-weaned beef calves. The prevalence of C. parvum ranged from 1.4 to 56.5% on dairy farms. Only three cases of C. parvum oocysts shedding in pre-weaned calves on beef farms were found. Only one case of C. andersoni infection in pre-weaned calves was detected and no infections of C. parvum in post-weaned calves were found. The prevalence of C. andersoni reached 35.5% on dairy farms and 61.7% on beef farms. Calves that were on pasture all year long, had a lower probability of C. andersoni infection than those calves kept in a cowshed during the winter season.     

Prevalence of Cryptosporidium spp. oocysts in cattle and wildlife in Morogoro region, Tanzania

Prevalences of Cryptosporidium spp. oocysts in cattle (n = 486) on five selected farms in Morogoro municipality and three species of herbivorous wildlife (n = 87) from Mikumi National Park, Morogoro, Tanzania, were determined using the modified Ziehl-Neelsen staining technique. Of 486 bovine faecal samples, 5.3% were positive for Cryptosporidium spp. The prevalence of Cryptosporidium was higher in calves less than 3 months of age compared to weaned calves and adults. Cryptosporidium spp. oocysts were detected in both diarrhoeic and non-diarrhoeic animals, but there was a significantly higher prevalence (P < 0.001) of oocyst shedding in diarrhoeic than in non-diarrhoeic animals. Of the 87 faecal specimens from the wildlife species, 36 were from the African buffaloes (Syncerus caffer), 25 from zebra (Equus zebra) and 26 from the wildebeest (Connochaetes gnou). Cryptosporidium spp. oocysts were detected in eight (22%) buffaloes, seven (28%) zebras and seven (27%) wildebeests. Confirmation of the diagnosis was performed using anti-Cryptosporidium monoclonal antibody specific for Cryptosporidium muris, Cryptosporidium parvum and Cryptosporidium baileyi (Pathasure Cryptosporidium test kit).     

Prevalence of Cryptosporidium and Giardia in roe deer (Capreolus capreolus) and wild boars (Sus scrofa) in Galicia (NW, Spain)

Faecal samples from 224 roe deer (Capreolus capreolus) and 381 wild boars (Sus scrofa) shot during the 2008-2009 hunting season (August-January) in Galicia (NW Spain) were examined to determine the presence and intensity of infection by Cryptosporidium and Giardia. Analysis of a single sample from each of the roe deer revealed that the prevalence of cryptosporidiosis and giardiosis was 1.3% and 5.3% respectively. The prevalence of Giardia infection was significantly higher in juvenile female roe deer than in adult females, but no other significant differences were found in relation to age and sex. In wild boars, the prevalence of cryptosporidiosis and giardiosis was 7.6% and 1.3% respectively. The prevalence of Cryptosporidium infection was significantly higher in juvenile male wild boars than in adult males, but no other significant differences were found in relation to age or sex. In both groups of wild animals, the number of Cryptosporidium oocysts per gram of faeces (OPG) ranged from 5 to 200 and the number of Giardia cysts per gram of faeces (CPG) was between 5 and 47; there were no significant differences between the two groups with respect to number of infections. This is the first large study of Cryptosporidium and Giardia in roe deer and wild boars in hunting areas in Spain and the results demonstrate a low, but widespread prevalence of Cryptosporidium and Giardia in these animals.     

Campylobacter infections in calves, piglets, lambs and kids in Trinidad.

Faeces or rectal swabs from 689 diarrhoeic and non-diarrhoeic animals were cultured for thermophilic campylobacters and their antibiograms were determined. Three hundred and fifteen (45.7%) samples were positive for Campylobacter. Piglets had the highest prevalence, 79.3% (233/294) and lambs, the lowest with 17.9% (15/84) being positive. The difference was statistically significant (P < or = 0.01; chi 2). In calves, 20.5% (60/293) and in kids 38.9% (7/18) were positive for campylobacters. The prevalence of infection was not significantly (P > or = 0.05; chi 2) different between diarrhoeic (46.1%) and non-diarrhoeic (45.1%) animals nor between male (47.5%) and female (43.8%). The frequency of isolation of campylobacters harvested from semi-intensively managed animals (75.4%) was, however, significantly higher (P < or = 0.001; chi 2) than from intensively or extensively managed animals. Overall, C. coli strains (32.8%) were more frequently isolated than C. jejuni strains (12.9%) and the difference was significant (P < or = 0.001; chi 2). Biotype I accounted for 67.3% (152/226) of C. coli and 64.0% (57/89) of C. jejuni strains isolated. A total of 245 (77.8%) strains of Campylobacter exhibited resistance to one or more antibiotics and was highest to streptomycin (76.5%), kanamycin (28.6%) and neomycin (26.7%). It was concluded that Campylobacter infections were widespread in livestock in Trinidad, particularly C. coli in piglets.     

Cryptosporidiosis in neonatal calves: 277 cases (1986-1987)

From January 1986 through December 1987, 277 cases of cryptosporidiosis in calves were diagnosed by the South Dakota State University Diagnostic Laboratory. Cryptosporidium sp was the only pathogen identified in 142 (51.3%) of the calves. Concurrent infections with rotavirus, coronavirus, Escherichia coli, Salmonella sp, bovine viral diarrhea virus, or other pathogens were identified in the remaining 135 calves. After elimination of cases involving autolyzed specimens or calves with chronic diarrhea, records of 11 calves with acute, severe cryptosporidiosis were identified in which Cryptosporidium sp was the only pathogen.     

Prevalence and risk factors associated with Cryptosporidium spp. infection in young domestic livestock in India

A total of 938 faecal samples (461 cattle calves, 264 buffalo calves, 55 lambs, 116 kids and 42 piglets) from different livestock farms and individual small holdings in six targeted states of India were collected and screened by modified Ziehl–Neelsen staining technique to determine the prevalence of Cryptosporidium spp. and its association with age, sex, season and faecal consistency in domesticated animals. Overall, 16.2 % of the animals were positive for Cryptosporidium infection with prevalence of 16.3, 24.2, 1.8, 3.5 and 19.1 % in cattle calves, buffalo calves, lambs, kids and piglets, respectively. The prevalence of infection was significantly higher (p?<?0.05) in bovines (19.3 % cattle and 33.7 % buffalo) below 1 month of age than in animals between 1 and 3 months of age. But in piglets, it was higher in the age group of 1 to 3 months (22.6 %) than in younger animals (9.1 %). Also, higher prevalence (p?>?0.05) was recorded in females than in males. Seasons had a significant effect (p?<?0.05) on the prevalence of infection in large ruminants, with the highest prevalence in monsoon (cattle 28.8 % and buffalo 36.6 %) followed by pre-monsoon and post-monsoon season. However, in case of sheep and goats, the prevalence was higher (p?>?0.05) in post-monsoon than in monsoon season. A high degree of association was noticed between Cryptosporidium infection and diarrhoea in ruminants screened during the present study. But, in case of pigs, the prevalence was higher in non-diarrhoeic than in diarrhoeic animals. Genotyping of Cryptosporidium spp. based on nested PCR amplification of partial 18S rRNA and its subsequent digestion with SspI, VspI and MboII restriction enzymes revealed prevalence of Cryptosporidium parvum in representative number of positive samples of cattle, buffalo and goats.     

Cryptosporidium infection in non-human hosts in Malawi

Of 1346 faecal samples from the Chikwawa and Thyolo districts of Malawi, analysed for the presence of Cryptosporidium oocysts between October 2001 and May 2003, 61.3% were from cattle (29.8% of these were from calves <6 months old). Cryptosporidium oocysts were detected during all three seasons studied in Chikwawa and Thyolo. In Chikwawa, 13.6% of adult cattle and 11.7% of calves were infected, compared to 28.9% of adult cattle and 36.7% of calves in Thyolo. Dependent on season, between 7.8% and 37.7% (Chikwawa) and 16.7% and 39.3% (Thyolo) of cattle samples contained oocysts. In Chikwawa, the highest percentage of infections occurred in the cool season, whereas in Thyolo, the highest percentage of infections occurred in the dry season. Faecal samples from goats [n=225], pigs [n=92], sheep [n=6]), rabbits, guinea pigs, chickens, ducks, turkeys, doves and guinea fowls were also analysed. Up to 5.6% of goat samples contained oocysts in Chikwawa, compared to between 16.7% and 39.3% in Thyolo. Again, in Chikwawa, the highest percentage of infections occurred in the cool season and the lowest in the rainy season, whereas, in Thyolo, the highest percentage of infections occurred in the dry season and the lowest in the cool season. In pigs, more infections were detected in the dry season in Chikwawa, but infections in the cool season were similar (17.7%), whereas in Thyolo, infections occurred in all three seasons (17.9% in the rainy season, 25% in the cool season and 60% in the dry season). Of ten diarrhoeic, oocyst positive cattle faecal samples collected from Chikwawa and subjected to PCR-RFLP, four oocyst positive samples (two from heifers, one from a cow and one unknown) were amplified at an 18S rRNA and Cryptosporidium oocyst wall protein (COWP) loci. RFLP of the 18S rRNA locus indicated that Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium bovis and/or Cryptosporidium ryanae DNA, or a mixture of them was present. Cryptosporidium parvum DNA was identified in one sample that amplified at the COWP locus, indicating the presence of the major zoonotic Cryptosporidium species in Malawi.     

Comparison of two techniques for diagnosis of cryptosporidiosis in diarrhoeic goat kids and lambs in Cyprus

This study was conducted in the Larnaca area of Cyprus and included 28 goat and 15 sheep flocks suffering from neonatal diarrhoea (>20%). Faecal samples from diarrhoeic animals revealed that 25 of the 28 goat and 12 of the 15 sheep flocks were positive for Cryptosporidium. The ELISA was more accurate in the diagnosis of cryptosporidiosis compared to the Ziehl-Neelsen staining technique (P?相似文献   

Excretion of Cryptosporidium oocysts by goats in relation to age and season in the dry zone of Sri Lanka.

Pattern of Cryptosporidium oocyst shedding in relation to age and season was investigated monthly from May 1999 to April 2000 in three groups (24 goats per group) of naturally infected goats (from 1 month of age). The three groups designated 1, 2 and 3 were studied for 12, 6 and 3 months, respectively. An association between Cryptosporidium oocyst counts and age was demonstrated. In Group 1, oocyst excretion in the first, second and fourth months of age were significantly higher than that in 6, 7, 8, 9 and 12 months of age (p<0.01), whereas in Group 2, oocyst excretion in the first month of age was significantly higher than that in 2, 4, 5 and 6 months of age (p<0.01). The 3-month observations made in Group 3 showed high oocyst excretion during 1 and 3 months of age. The mean maximum count for Group 1 was 592 oocyst per gram of feces when the animals were 2 months old, while in Groups 2 and 3, this was observed at 3 months of age and the oocyst counts were 787 and 520, respectively. A close association between the prevalence of the Cryptosporidium infection and age of the animal was also observed (p<0.01). At least one-third of the Group 1 animals were excreting Cryptosporidium oocysts during the first 5 months of age. Goats excreted Cryptosporidium oocysts irrespective of the dry or rainy season. The long periods of Cryptosporidium oocyst shedding by goats may have implications for the epidemiology of the disease in susceptible hosts.     

Prevalence of Cryptosporidium infection in goats in selected locations in three agroclimatic zones of Sri Lanka

The prevalence of Cryptosporidium oocysts in the faeces of 1020 goats in three age categories was examined during 1999 in selected locations of three agroclimatic zones of Sri Lanka. The oocysts were demonstrated using the Sheather's sucrose flotation method followed by staining with the modified Ziehl Neelsen technique. Cryptosporidium oocysts were detected in animals from all agroclimatic zones with the highest prevalence of infection in the dry zone (33.6%) compared with 24.7 and 21.7% in the intermediate zones and wet, respectively (P<0.001). Overall, Cryptosporidium oocyst counts were significantly higher in goats of <6 months and 7-12 months of age groups compared with goats of >12 months of age (P<0.001). Cryptosporidium oocysts were detected in 291/1020 (28.5%) animals, while 194/1020 animals (19%), 84/1020 animals (8.2%) and 13/1020 animals (1.3%) excreted low (1-1000 oocysts per gram of faeces), moderate (1000-5000 oocysts per gram of faeces) and high (>5000 oocysts per gram of faeces) counts, respectively. The mean Cryptosporidium count was 383 oocysts per gram of faeces. The majority of the infected goats were asymptomatic. These animals are likely to play an important role in the epidemiology of cryptosporidiosis in goat kids and humans.     

Genotyping of Cryptosporidium parvum isolates in bovine population in Kolkata and characterization of new bovine genotypes

Cryptosporidium infection may have adverse effect in health and production potential of cattle herd. The exact profile of Cryptosporidium infection in bovine population of India in general, particularly from Kolkata is scarce. We here report systematic investigation of clinical and genetic profiling of promiscuous Cryptosporidium infection in selected representative cattle farms from Kolkata as well as some surrounding local areas. The current study was conducted in the period of October to September, 2000–2001 with 149 diarrhoeic and non-diarrhoeic cattle of different age groups from two Government cattle farms, Harringhata Cattle Unit and Kalyani State Livestock Farm and animals raised by local farmers. Among these 149 samples, diarrhoea was recorded in 79 cases (53%) and non-diarrhoeic in 70 (46.9%). Out of 149 faecal samples screened microscopically, 32.9% from diarrhoeic faecal samples and 7.1% from healthy faecal samples revealed the presence of oocysts. Cryptosporidium genus was confirmed by DNA typing with nested PCR. The PCR-RFLP analysis was carried out for genotype identification. In course of PCR-RFLP, unique band patterns were obtained in two of our samples. The unusual RFLP products were characterized by DNA sequencing and homology analysis with other reported variants. This is the first report of identification and characterization of such a variant from the area of present investigation. Further study will be required to understand the phylogenetic origin and functional significance in virulence and morbidity of this genotype.     

Detection of rotavirus antigen in diarrhoeic and non-diarrhoeic piglets in Nigeria

Faecal samples from 96 piglets with acute gastroenteritis and 41 samples from non-diarrhoeic piglets were investigated for porcine rotavirus (PRV) antigens by enzyme-linked immunosorbent assay (ELISA). PRV was detected in 43 of 96 (44.8%) in the diarrhoeic group whilst none of the samples in the non-diarrhoeic group was positive for PRV (P less than 0.01). Age distribution of infection showed a higher infection rate of 30.2% in piglets aged 1-3 weeks, which was significantly higher (P less than 0.05) than in piglets aged 4-6 weeks, where the infection rate was 14.6 per cent. No PRV antigen was detected in diarrhoeic piglets above 6 weeks of age. Titration of 10 randomly selected ELISA-positive samples showed titres ranging from 512 to greater than or equal to 4.096.     

Epidemiological studies on equine cestodes in central Spain: infection pattern and population dynamics

An epidemiological study on equine cestodosis was carried out in central Spain. A total of 372 digestive tracts from equids slaughtered in abattoirs located in central Spain were studied from November 2001 to May 2004. Anoplocephala perfoliata was detected in 24% of the animals and Anoplocephala magna in 18%. Individual tapeworm burden was from 1 to 491 tapeworms for A. perfoliata and from 1 to 64 tapeworms for A. magna. Low tapeworm burdens (less than 30 cestodes) predominated significantly (p < 0.01) in all seasons for both species.

Seasonal prevalence of infection by A. perfoliata was significantly higher (p < 0.01) in autumn (37.5%) and winter (32.3%) than in spring (9.2%) and summer (10.8%). Immature tapeworms were detected throughout summer (11%), autumn (23.4%) and winter (26.6%), signalling a summer to winter risk period for tapeworm infection in our conditions. Mature non-gravid tapeworms were collected in all seasons, with a decreasing pattern from summer (89%) to spring (6.7%). Conversely, gravid tapeworms showed an increasing pattern, from 0 in summer to a maximum (93.3%) in spring. Since prevalence of infection was significantly higher in winter than in spring, winter seems to be the season when more eggs would be available to be eaten by mites. A. perfoliata infection was detected in three different periods throughout the 3 year study: autumn 2001–winter 2002, summer 2002–spring 2003 and autumn 2003–spring 2004. This epidemiological pattern seems to describe the dependence of A. perfoliata to humidity in warm dry climate. In our conditions, A. perfoliata appears to follow a pattern of having only one generation per year, with a marked dependence on humidity. According to the results, autumn rainfall would influence the length, and late spring rainfall the appearance, of each annual generation.

A. magna showed a different pattern. Infection was detected throughout the whole study period. Seasonal prevalence was higher in autumn (25.5%) than in winter (14.9%), spring (12.1%) and summer (10.5%), but the differences were not statistically significant. Non-gravid A. magna tapeworms could be detected almost throughout the year but percentages were significantly higher (p < 0.01) in autumn (50.2%), indicating recent ingestion, than in the other seasons (30% in summer, 12.8% in winter and 0% in spring). However, data from spring were not enough to discard the season as a risk period for A. magna infection.     

Infection with Cryptosporidium spp. in humans and cattle in Manitoba.

Between October 1, 1983 and October 31, 1984, fecal specimens from 3656 persons with enteritis and 182 calves, representing 148 herds having a neonatal diarrhea problem, were examined for oocysts of Cryptosporidium spp. Oocysts were found in 1% of human and 25% of bovine specimens. All infected persons were immunocompetent. Children under five years of age had an infection rate of 25/100,000 compared to 1.4/100,000 in older people (p less than 0.005). Rates in northern communities were four to seven times as high as those in southern Manitoba. Human infections occurred most commonly in late summer and fall. In beef calves infection occurred in winter and spring, the calving season in Manitoba. Epidemiological association between the infection in people and in cattle could not be established.     

Virulence gene profiles and intimin subtypes of Shiga toxin-producing Escherichia coli isolated from healthy and diarrhoeic calves

The virulence properties of Shiga toxin-producing Escherichia coli (STEC) strains isolated from diarrhoeic and non-diarrhoeic calves were compared. The strains were also tested for O157:H7, O111 and O26 serotypes, using PCR and conventional serotyping methods. E coli strains isolated from 297 faecal samples, from 200 diarrhoeic and 97 non-diarrhoeic calves, were screened by multiplex PCR assay for the stx1, stx2, eae and Ehly virulence genes. STECs were recovered from 8 per cent of diarrhoeic calves and 10.3 per cent of non-diarrhoeic calves. The predominant virulence gene profile was stx1/eae/Ehly (47.3 per cent) among isolates from diarrhoeic calves and eae/Ehly (36.8 per cent) among isolates from non-diarrhoeic calves. Among three tested serogroups, the predominant serogroup was O26 (18.4 per cent), and O157:H7 was not detected. Intimin subtyping by restriction fragment length polymorphism analysis revealed only three intimin subtypes (β, γ and ). A significant difference was observed in the distribution of Int- between two groups. Int- was present in 50 per cent of the isolates from diarrhoeic calves and in 11.1 per cent of the isolates from non-diarrhoeic calves; this difference was statistically significant (P=0.01).     

Occurrence and characteristics of enterohemorrhagic Escherichia coli O157 in calves associated with diarrhoea

Little is known of the association of enterohemorrhagic Escherichia coli O157:H7/NM (EHEC O157) with disease in naturally infected calves, although cattle have been known as a major source for EHEC O157 outbreaks in humans. In this study, we investigated the occurrence of EHEC O157 in calves associated with/without diarrhoea to examine if EHEC O157 is involved in calf diarrhoea and to characterize the isolates. Four hundred and ninety eight diarrhoeic and non-diarrhoeic young calves from 115 different farms were examined. Of 244 diarrhoeic calves, 24 (9.8%) were positive for EHEC O157, and of 254 non-diarrhoeic calves, 7 (2.8%) were positive. EHEC O157 was recovered from 12/76 (15.79%) of diarrhoeic calves less than 2-week-old, and no EHEC O157 was detected in this age group of non-diarrhoeic calves. This implicates EHEC O157 as a possible cause of the disease in naturally infected neonatal calves. The occurrence of EHEC O157 was relatively lower in the older calves (aged older than 8 weeks) and no significant difference was found in the occurrence rates between these diarrhoeic and non-diarrhoeic calves. PCR analysis of virulence markers revealed that the isolates carried various virulence genes such as Ehly, eae, stx1 and stx2, which underlines the potential importance of these attributes for the infection, colonization and possible pathogenesis of calf diarrhoea.