Prevalence of Cryptosporidium and Giardia infections in cattle in Aragón (northeastern Spain)

Molecular analysis of cryptosporidiosis on cattle farms in Gran Canaria, Canary Islands (Spain)

Cryptosporidium spp. infections in calves cause serious economic losses in livestock and pose an important zoonotic risk. The aim of this study was to investigate the prevalence of Cryptosporidium spp. in cattle on the island of Gran Canaria. Faecal samples were collected from calves and adult cattle from a total of 15 farms, and a questionnaire survey was conducted to farmers. The presence of Cryptosporidium spp. oocysts in faeces was determined by microscopy, showing infection rates of 45.9% in calves and 4.1% in adults, with positive correlation with the faecal scores of infected animals (p < 0.0001). Samples were amplified by PCR targeting SSU rRNA, with positivity rates for calves and adults being 51.7% and 31.7%, respectively. The PCR-positive samples were further genotyped and sequenced for the 60 kDa glycoprotein gene (GP60) and the microsatellite TP14. Four Cryptosporidium species were identified (C. parvum, C. ryanae, C. bovis, and C. andersoni), of which C. parvum was the most frequent in calves (45.8%) and adults (29.2%). GP60 sequencing revealed that all C. parvum samples belonged to the IId family, the most frequent subtypes being IIdA22G1 and IIdA23G1. Overall, the results of this study demonstrate a high occurrence of Cryptosporidium spp. in both calves and adult cattle, including the zoonotic IId family of C. parvum. These findings have significant implications for cattle farming and public health. The lack of awareness among farmers regarding cryptosporidiosis highlights the need for caution to prevent epidemiological outbreaks that could impact both human and livestock health.

Prevalence and risk factors of Cryptosporidium spp. and Giardia infestation in cattle and in broiler chickens in Algeria

Cryptosporidiosis and giardiasis are zoonotic protozoan diseases with significant public health and economic concerns. In Algeria, epidemiological data on these parasites in livestock are limited. This study aimed to estimate the prevalence of Cryptosporidium spp. and Giardia in dairy calves and broiler chickens and to identify the associated risk factors. A microscopic analysis of 200 faecal samples revealed a Cryptosporidium spp. prevalence of 56% in calves and 60% in broiler chickens, while the Giardia prevalence was 8% in calves and absent in chickens. In cattle, the data showed that age constituted a potential risk factor for both parasites (P < 0.000 1 for Cryptosporidium; P < 0.000 5 for Giardia). Interestingly, the risk of a Cryptosporidium infection decreased with age, while the Giardia infestation risk increased. The sex was not a significant factor for Cryptosporidium (P = 0.115 0), but was impactful for Giardia (P < 0.000 1), with males at higher risk. These results highlighted the distinct epidemiological characteristics of Cryptosporidium and Giardia infestations in Algerian livestock. The contrasting age-related risks and sex-specific susceptibility to Giardia underline the need for targeted, age and sex prevention strategies. This study provides valuable data to inform public health policies and to improve livestock management practices in Algeria, contributing to the wider understanding of these zoonotic parasites in North African agricultural farming.

Prevalence of Cryptosporidium parvum, Giardia duodenalis and Eimeria spp. in diarrhoeic suckling calves from north-western Spain and analysis of their interactions

Although Cryptosporidium parvum, Giardia duodenalis and some Eimeria species are frequently involved in neonatal calf diarrhoea (NCD), detailed studies on their interactions are scarce. Therefore, a cross-sectional study including faecal samples from 404 diarrhoeic calves aged 0-30 days was performed. Cryptosporidium oocysts and G. duodenalis cysts were detected by immunofluorescence antibody test and positive samples were molecularly characterized. Eimeria oocysts were microscopically detected using the modified McMaster technique and morphometric species identification was performed. Cryptosporidium infections (53.7%) predominated over those by G. duodenalis (12.4%) and Eimeria spp. (6.9%). Three Cryptosporidium species were identified: C. parvum (98.0%), C. bovis (1.0%) and C. ryanae (1.0%). Eleven C. parvum zoonotic subtypes were detected, with IIaA15G2R1 as the most common; only G. duodenalis assemblage E was identified. Moreover, 10 Eimeria species were found, being Eimeria ellipsoidalis (96.4%), Eimeria bovis (85.7%), and Eimeria zuernii (71.4%) predominant. A significant positive association between G. duodenalis and Eimeria spp. was detected as well as a negative association between C. parvum and Eimeria spp. Our results showed that C. parvum wasprevalent in diarrhoeic calves under 21 days of life; Eimeria spp. and G. duodenalis were especially common in animals in their fourth week of life. Concurrent infections increased with age. Moreover, the study also revealed potential public health risks since a noticeable percentage of animals were infected with C. parvum zoonotic subtypes. Further studies are needed for determining the role of these parasites in co-infections with other enteropathogens and their implications in the pathogenicity of NCD.

Effect of Dietary Supplementation of Chestnut and Quebracho Tannin Supplementation on Neonatal Diarrhoea in Preweaning Calves

Neonatal calf diarrhoea (NCD) poses a significant health challenge in cattle herds, resulting in considerable economic losses and antimicrobial use. In response to the escalating threat of antimicrobial resistance, viable alternatives are imperative, aligning with European policies. This study evaluated the in-milk supplementation of the chestnut and quebracho tannin extract in preweaning calves on performance, diarrhoea occurrence, Cryptosporidium spp. shedding, protein digestibility, and intestinal health. Twenty newborn calves were divided, after colostrum administration, into two experimental groups for 30 days as follows: the control (CTRL) was fed with whole milk and solid feed, and tannins (TAN) were fed whole milk supplemented with 6/g day of tannin extract and solid feed. Faecal samples were collected on days 0, 3, 7, 14, and 30 for the evaluation of Cryptosporidium oocyst shedding and protein digestibility. Faecal consistency was evaluated during the sampling using the faecal score scale (0-3 scale, considering diarrhoea > 1). The results showed a significant reduction in diarrhoea frequency in the TAN compared to the CTRL group (p < 0.05) over 30 days of the trial. The prevalence of Cryptosporidium spp. was generally low (12%), considering all analysed samples. Protein digestibility revealed comparable values for the TAN and CTRL groups, suggesting that tannins did not negatively affect milk protein availability. In conclusion, the in-milk supplementation of 6/g day of the chestnut and quebracho tannin extract could be considered a valuable functional feed additive to decrease NCD occurrence, thus supporting animal health and decreasing antibiotic use in livestock.

Giardia duodenalis (Styles, 1902) in Cattle: Isolation of Calves with Diarrhoea and Manure Treatment in the Lagoon Presented as Risk Factors in Latvian Herds

Giardia duodenalis is a waterborne zoonotic protozoan that causes gastrointestinal tract inflammation in humans, cattle, and other animals. The aim of the present study was to estimate the prevalence and potential risk factors for Giardia infection in cattle in Latvia. During 2020-2021, a total of 973 individual faecal samples from cattle aged from 1 day to 12 years old, from 32 cattle herds, were tested for Giardia cyst presence with immunofluorescence staining followed by Giardia assemblage differentiation targeting beta-giardin gene. Using a questionnaire, information was collected to estimate the potential risk factors for G. duodenalis infection in cattle herds. Giardia was found in 8.4% of the examined cattle with a mean intensity of 5756 cysts per gram of faeces. The highest prevalence was observed in the 0 to 3-month-old calves (16.4%). At least one Giardia shedding animal was found in 27 herds with an overall prevalence of 84.4%. Significantly higher prevalence was found for cattle infected with G. duodenalis assemblage E compared to that infected with assemblage A: 88.7% and 11.3%, respectively. Protective factors such as age and rodent control and change of shoes were found to be significant for Giardia infection, while isolating calves for diarrhoea and water bodies (ponds/lakes) in pasture were potential risk factors in Latvian cattle.

Giardia duodenalis Styles, 1902 Prevalence in Cattle (Bos taurus Linnaeus, 1758) in Europe: A Systematic Review

Giardia duodenalis Styles, 1902 is an infectious agent which can cause enteritic disease in cattle (Bos taurus Linnaeus, 1758) worldwide. As a zoonotic protozoan, it is important to acknowledge Giardia prevalence and assemblages found in cattle and risk factors associated with the Giardia infection in herds. This systematic review aims to estimate the prevalence of G. duodenalis and its assemblages in cattle and to identify the risk factors associated with Giardia infection in cattle in Europe. A systematic review was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to collect information from published studies in Europe. A total of 1414 studies were identified and 17 relevant studies were included in this review. Mean Giardia prevalence in cattle in Europe was 35.1%, with the highest prevalence found in neonatal animals (39.6%), but mean heard prevalence was 67.0%. Mixed infections of Giardia assemblages A and E were found most frequently (55.6%), while assemblages A and B were found more frequently in animals under 24 months old. Risk factors, such as deep litter with run-out, prolonged calf contact with the dam, and seasonality, such as winter and spring, were found to be potential risk factors for Giardia presence in the herds.

Occurrence of Cryptosporidium and Giardia in raw and finished drinking water in north-eastern Spain

This paper collects the first large-sample-size study on the presence of Cryptosporidium oocysts and Giardia cysts in drinking water plants at the 20 most populated towns in Aragón (north-eastern Spain). Samples of influent raw water and effluent finished water were collected from each plant during different seasons and processed according to USEPA Method 1623. Cryptosporidium oocysts and Giardia cysts were detected in samples collected from 55% and 70% plants, respectively, with nine plants being positive for both protozoa and only four plants being negative over the study period. Both parasites were identified in the raw water throughout the year, with a lower frequency in autumn and a peak in winter, at a mean concentration of 67±38 oocysts per 100l and 125±241 cysts per 100l. The turbidity of raw water was not related to the presence or concentration of (oo)cysts, and the (oo)cyst removal efficiency was not related to the type of water treatment. One or both pathogens were identified in the finished water in 7 out of 11 plants with a conventional treatment process (coagulation, flocculation, sedimentation, filtration, and disinfection processes) compared to 4 out of 9 plants that did not apply one of the pre-chlorination treatment steps. Protozoa were detected in the finished water of positive plants at a mean concentration of 88±55 oocysts per 100l and 37±41 cysts per 100l, and most of them excluded propidium iodide so were considered potentially viable. The ubiquity of these parasites in the drinking water sources and the inefficiency of conventional water treatment in reducing/inactivating them may present a serious public health issue in this geographical area.

Comparison of different diagnostic techniques for the detection of cryptosporidiosis in bovines

Aim:

Aim of the present study was to compare different methods, viz., Sheather's sugar flotation (SSF), Ziehl-Neelsen (ZN), Kinyoun's acid-fast method (KAF), safranin-methylene blue staining (SMB), and negative staining techniques such as nigrosin staining, light green staining, and malachite green staining for the detection of Cryptosporidium spp. oocysts in bovines.

Materials and Methods:

A total of 455 fecal samples from bovines were collected from private, government farms and from the clinical cases presented to Department of Medicine, Veterinary College, Bengaluru. They were subjected for SSF, ZN, KAF, SMB and negative staining methods.

Results:

Out of 455 animal fecal samples screened 5.71% were found positive for Cryptosporidium spp. oocysts. The species were identified as Cryptosporidium parvum in calves and Cryptosporidium andersoni in adults based on the morphological characterization and micrometry of the oocysts.

Conclusions:

Of all the techniques, fecal flotation with sheather's was found to be more specific and sensitive method for the detection of Cryptosporidium spp. oocysts. Among the conventional staining methods, the SMB gives better differentiation between oocysts and yeast. Among the three negative staining methods, malachite green was found sensitive over the other methods.

Development of a framework for genotyping bovine-derived Cryptosporidium parvum, using a multilocus fragment typing tool

Background

There is a need for an integrated genotyping approach for C. parvum; no sufficiently discriminatory scheme to date has been fully validated or widely adopted by veterinary or public health researchers. Multilocus fragment typing (MLFT) can provide good differentiation and is relatively quick and cheap to perform. A MLFT tool was assessed in terms of its typeability, specificity, precision (repeatability and reproducibility), accuracy and ability to genotypically discriminate bovine-derived Cryptosporidium parvum.

Methods

With the aim of working towards a consensus, six markers were selected for inclusion based on their successful application in previous studies: MM5, MM18, MM19, TP14, MS1 and MS9. Alleles were assigned according to the fragment sizes of repeat regions amplified, as determined by capillary electrophoresis. In addition, a region of the GP60 gene was amplified and sequenced to determine gp60 subtype and this was added to the allelic profiles of the 6 markers to determine the multilocus genotype (MLG). The MLFT tool was applied to 140 C. parvum samples collected in two cross-sectional studies of UK calves, conducted in Cheshire in 2004 (principally dairy animals) and Aberdeenshire/Caithness in 2011 (beef animals).

Results

Typeability was 84 %. The primers did not amplify tested non-parvum species frequently detected in cattle. In terms of repeatability, within- and between-run fragment sizes showed little variability. Between laboratories, fragment sizes differed but allele calling was reproducible. The MLFT had good discriminatory ability (Simpson’s Index of Diversity, SID, was 0.92), compared to gp60 sequencing alone (SID 0.44). Some markers were more informative than others, with MS1 and MS9 proving monoallelic in tested samples.

Conclusions

Further inter-laboratory trials are now warranted with the inclusion of human-derived C. parvum samples, allowing progress towards an integrated, standardised typing scheme to enable source attribution and to determine the role of livestock in future outbreaks of human C. parvum.

Cryptosporidium and Giardia in Danish organic pig farms: Seasonal and age-related variation in prevalence, infection intensity and species/genotypes

Although pigs are commonly infected with Cryptosporidium spp. and Giardia duodenalis, including potentially zoonotic species or genotypes, little is known about age-related infection levels, seasonal differences and genetic variation in naturally infected pigs raised in organic management systems. Therefore, the current study was conducted to assess seasonal and age-related variations in prevalence and infection intensity of Cryptosporidium and Giardia, evaluate zoonotic potential and uncover correlations between species/genotypes, infection intensity and faecal consistency. Shedding of oocysts and cysts ((oo-)cysts) was monitored at quarterly intervals (September 2011-June 2012) in piglets (n = 152), starter pigs (n = 234), fatteners (n = 230) and sows (n = 240) from three organic farms in Denmark. (oo-)Cysts were quantified by immunofluorescence microscopy; and 56/75 subsamples from Cryptosporidium infected pigs were successfully analysed by PCR amplification and partial sequencing of the small subunit (SSU) 18S rRNA and hsp70genes, while 13/67 Giardia subsamples were successfully analysed by amplification and partial sequencing of the 18S rRNA and the gdh genes. Altogether, Cryptosporidium or Giardia infections were observed in 40.9% (350/856) and 14.0% (120/856) of the pigs, respectively, including 8.2% (70/856) infected with both parasites. Prevalence, intensity of infections and presence of Cryptosporidium species varied significantly between age-groups; 53.3% piglets, 72.2% starter pigs, 40.4% fatteners and 2.9% sows were infected with Cryptosporidium, whereas 2.0% piglets, 27.4% starter pigs, 17.8% fatteners and 5.0% sows were infected with Giardia. The overall prevalence was stable throughout the year, except for dual-infections that were more prevalent in September and December (p < 0.05). The infection intensity was age-related for both parasites, and dual-infected pigs tended to excrete lower levels of oocysts compared to pigs harbouring only Cryptosporidium. Likewise, pigs infected with Cryptosporidium scrofarum excreted fewer oocysts (mean CPG: 54,848 ± 194,508CI: 9085-118,781) compared to pigs infected with Cryptosporidium suis (mean OPG: 351,035 ± 351,035CI: 67,953-634,117). No correlation between faecal consistency and (oo-)cyst excretion levels was observed. Of the successfully genotyped isolates, 38/56 (67.9%) were C. scrofarum and 18/56 (32.1%) were C. suis, while the livestock specific G. duodenalis Assemblage E was detected in 11/13 (84.6%) isolates and the potentially zoonotic Assemblage A was identified in 2/13 (15.4%) isolates. Piglets exclusively hosted C. suis, with one exception, while starter pigs and fatteners predominantly hosted C. scrofarum. As organic pigs are partly reared outdoors, environmental contamination with Cryptosporidium and Giardia is inevitable. Nevertheless, the present data indicate that the potential public health risk associated with both of these parasites in Danish organic pig production seems to be negligible.

Assessment of zoonotic transmission of Giardia and Cryptosporidium between cattle and humans in rural villages in Bangladesh

Giardia and Cryptosporidium are important causes of diarrhoea in Bangladesh. The high prevalence of both parasites in humans and cattle in rural Bangladesh and the common use of water ponds by village inhabitants and their animals suggest a potential for zoonotic transmission. Direct transmission of Giardia and Cryptosporidium between cattle and their handlers and indirect transmission through water ponds was investigated. Faecal/stool samples were collected from 623 calves and 125 calf handlers in a cross-sectional survey. In two villages, water samples were collected monthly from water ponds and faecal/stool samples were collected monthly from inhabitants and their cattle. Giardia cysts and Cryptosporidium oocysts were detected in water samples and in faecal/stool samples and positive samples were genotyped, to determine their human or animal origin. The prevalence of Giardia and Cryptosporidium in calves was 22% and 5% respectively. In calf handlers, the prevalence of Giardia and Cryptosporidium was 11.2% and 3.2% respectively. Both in the cross-sectional survey and in the longitudinal study in the villages, G. duodenalis assemblage E was most prevalent in calves, while in humans assemblage AII, BIII and BIV were found. In cattle, Cryptosporidium parvum, C. bovis and C. andersoni were identified, but no Cryptosporidium sequences were obtained from humans. Giardia and Cryptosporidium were detected in 14/24 and 12/24 water samples respectively. G. duodenalis assemblage E and BIV (-like), as well as C. andersoni and C. hominis were identified. Although the presence of Giardia and Cryptosporidium in both water ponds suggests that water-borne transmission of Giardia and Cryptosporidium is possible, the genotyping results indicate that there is no significant direct or indirect (water-borne) transmission of Giardia between cattle and people in this area of rural Bangladesh. No conclusions could be drawn for Cryptosporidium, because of the low number of sequences that were obtained from human and water samples.

Multilocus genotyping of Giardia duodenalis in dairy cattle in Henan, China

Giardia duodenalis is a common and widespread intestinal protozoan parasite of both humans and animals. Previous epidemiological and molecular studies have identified Giardia infections in different animals and humans, but only limited information is available about the occurrence and genotypes of Giardia in cattle in China. In this study, we determined the occurrence of giardiasis and genetically characterized G. duodenalis in dairy cattle in Henan Province, central China. The overall prevalence of G. duodenalis was 7.2% (128/1777) on microscopic analysis, with the highest infection rate (22.7%) in calves aged less than 1 month. G. duodenalis assemblages and subtypes were identified with multilocus genotyping based on the SSU rRNA, β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. Two assemblages were detected in the successfully sequenced samples: assemblage A (n = 58), assemblage E (n = 21), with a mixed E and A assemblage (n = 2). Four novel subtypes of the gdh gene and seven of the bg gene were found among the G. duodenalis assemblage E isolates. Using the nomenclature for the multilocus genotype (MLG) model, nine novel multilocus genotypes E (MLGs E1-E9) and three MLGs A (a novel subtype AI, previously detected subtype AII-1, and a combination of both) were identified. MLG AII-1 identified in this study may be an important zoonotic subtype. The dairy cattle in Henan are a potential public health concern.

Short communication: effect of pomegranate-residue supplement on Cryptosporidium parvum oocyst shedding in neonatal calves

Cryptosporidium parvum is considered one of the most common enteropathogens, responsible for the high incidence of diarrhea and deleterious implications on immunity and health in neonatal calves. The pomegranate is well known for its health-promoting properties. Two experiments were designed to test the antiparasitical and antidiarrheal effects of concentrated pomegranate extract (CPE) supplement in milk in neonatal Holstein calves. Forty-one calves were randomly divided into control (n=20) and treatment (n=21) groups. For the first experiment, the treatment group was supplemented with 3.75% CPE in the daily milk ration, between 3 and 14 d of age, whereas the control group received only milk. Fecal samples were collected between d 5 and 13 to quantify Cryptosporidium oocysts, and the duration and intensity of diarrhea were evaluated. Reduced fecal oocyst count and diarrhea intensity and duration were revealed in the 3.75% CPE calves. No difference was noted in average daily gain between groups. In a second experiment, which was designed to test the effect of a lower CPE concentration (0.6% of daily milk allocation), no effects on fecal oocyst count and average daily gain were observed. However, compared with control, the lower CPE group was characterized by a shorter duration of diarrhea and higher weight gain among males at 14 d of age. These results suggest that the CPE supplement-to-calf milk ratio may potentially alleviate intestinal morbidity caused by Cryptosporidium.

Molecular characterization of Cryptosporidium isolates from beef calves under one month of age over three successive years in one herd in western France

Cohorts of pre-weaned calves were studied for Cryptosporidium infection over three successive years (2010-2012) in one beef cattle herd in western France. Each year 25-34 calves were sampled weekly from 3 days to one month of age in order to characterize oocyst output, Cryptosporidium species and clinical features associated with infection. Faecal samples were screened for the presence of oocysts using immunofluorescence analysis. DNA was extracted from positive samples and a PCR SSU rRNA followed by RFLP or sequencing was performed. For the subtyping of C. parvum, a gp60 PCR was carried out. Regardless of the year, 92-100% of the animals excreted oocysts on at least one sampling date. Depending on the year of observation, the age of highest prevalence varied. In contrast, the peak of excretion was systematically observed almost at the same age (2nd-3rd week of life) with excretion levels ranging from between 100 and 1.7 × 10(7)oocysts/g of faeces. Differences concerning clinical signs depending on the year of sampling were observed. Different species patterns were observed, with a predominance of C. bovis in the 1st year and a predominance of C. parvum in the last year. Moreover, two zoonotic subtypes of C. parvum, IIaA15G2R1 and IIaA18G2R1, were recorded in different years. This study shows that, in a given farm, the Cryptosporidium species and C. parvum subtypes identified as well as the prevalence of infection and level of excretion may vary greatly and show distinct patterns according to the year.

Giardiosis and other enteropathogenic infections: a study on diarrhoeic calves in Southern Germany

BACKGROUND

Diarrhoea induces massive problems in the rearing of calves. The aim of the study was to obtain current data about the frequency of Giardia spp., Cryptosporidium spp. and Eimeria spp. in diarrhoeic calves in Southern Germany with the particular focus on giardiosis.

RESULTS

1564 samples were analysed for the three pathogens using microscopical methods. Giardia spp. was detectable in 112/1564 samples (7.2%). The mean age was 46.5 days and the odds of being infected with Giardia spp. increased slowly up to 8 times from about 12 days to 30 days of age. There appeared to be no seasonal influence on the frequency of Giardia spp. A mono-infection with Giardia spp. was diagnosed in 46 calves (2.9%) whereas 15 calves (1.0%) had a mixed-infection with Cryptosporidium spp. and 51 calves (3.3%) with Eimeria spp. Cryptosporidium spp. and Eimeria spp. could be detected in 646/1564 samples (41.3%) and 208/1564 samples (13.3%), respectively, with a mean age of 11.3 and 55.0 days, respectively. The odds of being infected with Cryptosporidium spp. increased up to 4.5 times until an age of 10 days. After that the odds decreased continuously and was approaching zero at about 30 days. The odds of being infected with Eimeria spp. increased continuously up to 30 times from about 20 days to 60 days of age. There appeared to be no significant seasonal influence on the frequency of Cryptosporidium spp.; but there was one for Eimeria spp.: the odds of being infected with Eimeria spp. in March and April decreased by about half and increased up to 2.3 times between July and September. Additionally, as requested by the veterinarians, 1282 of those samples were analysed for E. coli, Rota-, Coronavirus and Cryptosporidium spp. using an ELISA. Obtained frequencies for these pathogens were 0.9%, 37.8%, 3.4% and 45.3% with a mean age of 24.8 days, 12.1 days, 9.0 days and 12.1 days, respectively.

CONCLUSIONS

The results indicate that in Southern Germany in addition to Eimeria spp., Giardia spp. seems to play a contributing role in diarrhoea in older calves, whereas Cryptosporidium spp. and Rotavirus are mostly relevant in young calves.

Molecular characterization of Cryptosporidium isolates from pre-weaned calves in western France in relation to age

Eighteen pre-weaned female calves from a single beef cattle herd in western France were sampled weekly from birth to 21/2 months of age in order to characterize Cryptosporidium oocyst output. 182 fecal samples were screened for the presence of oocysts after concentration using immunofluorescence analysis. DNA was extracted from positive samples and a PCR-RFLP protocol, with the restriction enzyme SspI and MboII, to amplify the partial SSU rRNA gene was performed. For the subtyping of Cryptosporidium parvum, a gp60 PCR was carried out. All animals excreted oocysts at at least one sampling date and 80% of the calves presented a mild diarrhea at at least one occasion, with no mortality. The prevalence of excretion reached 94% when calves were 17-23 days of age. The mean number of oocysts at the peak of excretion (10-16 days) was 5 × 10(5) oocysts per gram of feces. PCR-RFLP analysis was successful for 61 of 84 positive samples: 14 were identified as C. parvum, 15 as Cryptosporidium bovis, and 22 as Cryptosporidium ryanae. Ten mixed infections with all combinations of these species were also identified. Calves excreted the following Cryptosporidium species: C. parvum between 7 and 27 days of age, C. bovis between 11 and 38 days and C. ryanae from 19 to 72 days. The IIaA15G2R1 zoonotic subtype of C. parvum subtype was the only subtype identified. We observed the presence of different Cryptosporidium species depending on the age of the animals. This study showed that C. parvum and C. bovis can infect beef calf neonates at similar levels of oocyst excretion with or without clinical signs and that C. parvum isolates had zoonotic potential.

A Review of the Use of Organic Amendments and the Risk to Human Health

Historically, organic amendments—organic wastes—have been the main source of plant nutrients, especially N. Their use allows better management of often-finite resources to counter changes in soils that result from essential practices for crop production. Organic amendments provide macro- and micronutrients, including carbon for the restoration of soil physical and chemical properties. Challenges from the use of organic amendments arise from the presence of heavy metals and the inability to control the transformations required to convert the organic forms of N and P into the minerals available to crops, and particularly to minimize the losses of these nutrients in forms that may present a threat to human health. Animal manure and sewage biosolids, the organic amendments in greatest abundance, contain components that can be hazardous to human health, other animals and plants. Pathogens pose an immediate threat. Antibiotics, other pharmaceuticals and naturally produced hormones may pose a threat if they increase the number of zoonotic disease organisms that are resistant to multiple antimicrobial drugs or interfere with reproductive processes. Some approaches aimed at limiting N losses (e.g. covered liquid or slurry storage, rapid incorporation into the soil, timing applications to minimize delay before plant uptake) also tend to favor survival of pathogens. Risks to human health, through the food chain and drinking water, from the pathogens, antibiotics and hormonal substances that may be present in organic amendments can be reduced by treatment before land application, such as in the case of sewage biosolids. Other sources, such as livestock and poultry manures, are largely managed by ensuring that they are applied at the rate, time and place most appropriate to the crops and soils. A more holistic approach to management is required as intensification of agriculture increases.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy cattle from farms in China

Fecal samples of 2,056 dairy cattle from 14 farms were collected in three geographical regions of China and stained using a modified acid-fast staining technique to identify Cryptosporidium oocysts. A total of 387 (18.82%) positive samples were identified and further analyzed by polymerase chain reaction (PCR) using primers designed to amplify DNA fragments from the small subunit ribosomal RNA. The PCR products were sequenced and the sequences were deposited in the GenBank database under accession numbers EU369377-84 and GU070730-33. Phylogenetic analysis was performed and a distances matrix generated from these sequences confirmed the existence of Cryptosporidium (C.) parvum 'mouse' genotype, C. bovis, C. andersoni, C. hominis, and C. serpentis in cattle. These results represent the first report on the prevalence and genetic identification of Cryptosporidium species, and may contribute to a better understanding of the epidemiology of Cryptosporidium in cattle in China.

A multicentre prevalence study in Europe on Giardia duodenalis in calves, with molecular identification and risk factor analysis

The present study aimed to obtain data on the occurrence of Giardia duodenalis in calves in four major cattle rearing countries in Europe (Germany, UK, France and Italy), along with genotyping data and risk factors associated with these infections. A total of 2072 calves were sampled on 207 farms. The majority of the animals were Holstein dairy or mixed Holstein calves (n=1565 or 75.5%), and were female (n=1640 or 79.1%). The average age was 7.8 weeks (SD=4.1; median=7; range=2-16 weeks). All fecal samples were tested using a commercially available monoclonal antibody-based ELISA. The overall apparent prevalence of G. duodenalis for the four countries was 45.4% (n=942/2072) and the overall farm prevalence was 89.9% (186/207), with differences in both animal and farm prevalence between the four countries. The prevalence was significantly higher in animals up to 8 weeks (OR=1.88; P<0.001) compared to older calves, and several management factors including contact with the Dam, Frequency of cleaning of the Maternity Pens, and Disinfection of the Calf Housing were found to be associated with infection. Positive samples were withheld for genotyping using the β-giardin and triose phosphate isomerase gene: G. duodenalis assemblage E was most prevalent, although 43% of the isolates were typed as assemblage A, with differences in between countries. Furthermore, 32% of the examined samples was found to be a mixed assemblage A and E infection, which is consistent with previous reports. The results of the present study confirm previous findings in other European countries that G. duodenalis infections are common in calves. The infection especially occurs in animals younger than 2 months, and the proportion of positive animals gradually decreased with increasing age.

Cryptosporidium infection in a veal calf cohort in France: molecular characterization of species in a longitudinal study

Feces from 142 animals were collected on 15 farms in the region of Brittany, France. Each sample was directly collected from the rectum of the animal and identified with the ear tag number. Animals were sampled three times, at 5, 15 and 22 weeks of age. After DNA extraction from stool samples, nested PCR was performed to amplify partial 18S-rDNA and 60 kDa glycoprotein genes of Cryptosporidium. The parasite was detected on all farms. One hundred out of 142 calves (70.4%) were found to be parasitized by Cryptosporidium. Amplified fragments were sequenced for Cryptosporidium species identification and revealed the presence of C. parvum (43.8%), C. ryanae (28.5%), and C. bovis (27%). One animal was infected with Cryptosporidium ubiquitum. The prevalence of these species was related to the age of the animal. C. parvum caused 86.7% of Cryptosporidium infections in 5-week-old calves but only 1.7% in 15-week-old animals. The analysis of the results showed that animals could be infected successively by C. parvum, C. ryanae, and C. bovis for the study period. C. parvum gp60 genotyping identifies 6 IIa subtypes of which 74.5% were represented by IIaA15G2R1. This work confirms previous studies in other countries showing that zoonotic C. parvum is the dominant species seen in young calves.

Foodborne illness associated with Cryptosporidium and Giardia from livestock

Waterborne outbreaks caused by Cryptosporidium and Giardia are well documented, while the public health implications for foodborne illness from these parasites have not been adequately considered. Cryptosporidium and Giardia are common in domestic livestock, where young animals can have a high prevalence of infection, shedding large numbers of oocysts and cysts. Molecular epidemiological studies have advanced our knowledge on the distribution of Cryptosporidium and Giardia species and genotypes in specific livestock. This has enabled better source tracking of contaminated foods. Livestock generate large volumes of fecal waste, which can contaminate the environment with (oo)cysts. Evidence suggests that livestock, particularly cattle, play a significant role in food contamination, leading to outbreaks of cryptosporidiosis. However, foodborne giardiasis seems to originate primarily from anthroponotic sources. Foodborne cryptosporidiosis and giardiasis are underreported because of the limited knowledge of the zoonotic potential and public health implications. Methods more sensitive and cheaper are needed to detect the often-low numbers of (oo)cysts in contaminated food and water. As the environmental burden of Cryptosporidium oocysts and Giardia cysts from livestock waste increases with the projected increase in animal agriculture, public health is further compromised. Contamination of food by livestock feces containing Cryptosporidium oocysts and Giardia cysts could occur via routes that span the entire food production continuum. Intervention strategies aimed at preventing food contamination with Cryptosporidium and Giardia will require an integrated approach based on knowledge of the potential points of entry for these parasites into the food chain. This review examines the potential for foodborne illness from Cryptosporidium and Giardia from livestock sources and discusses possible mechanisms for prevention and control.

Cryptosporidium parvum in diarrheic calves detected by microscopy and identified by immunochromatographic and molecular methods

Cryptosporidium is an important protozoan parasite that causes diarrhea in neonates and young bovines. The objective of the present study was to determine the frequency of Cryptosporidium infection in animals of dairy farms of the Metropolitan Region (Santiago), Chile. Fecal samples of 205 newborn calves with diarrhea were studied and used for comparing the efficiency of two microscopic staining methods for diagnosis of the parasite, the auramine (AU) and a modified Ziehl-Neelsen (ZN) procedure. Out of the 205 fecal samples, we detected oocysts in 115 (56.1%) with AU and 102 (49.8%) with ZN. Comparison of results obtained with the two microscopic techniques showed significant difference (p<0.05), AU being more sensitive. On the other hand, concordance between the two methods was almost perfect (kappa value of 0.83). The results with these two operator dependent methods were confirmed using an operator independent immunochromatographic (IC) method. The IC method also enabled us to determine the identity of the parasite species as that of Cryptosporidium parvum. Identification of the parasite species was further corroborated by performing a Cryptosporidium species-specific polymerase chain reaction (PCR) test on few samples taken at random. Overall, the results showed a high number of infected animals suggesting the parasite C. parvum as a major parasitic disease agent of neonatal calves with diarrhea in dairy farms of the Metropolitan Region (Santiago) of Chile.

Genotype and subtype analysis of Cryptosporidium isolates from calves and lambs in Galicia (NW Spain)

Faecal specimens from diarrhoeic pre-weaned calves (n=61) and lambs (n=127) collected over a 1-year period (2008–2009) at 27 cattle and 28 sheep farms in Galicia (NW Spain) were examined for the presence of Cryptosporidium oocysts and positive specimens were selected for molecular examination. Overall, 30 calves (49·2%) and 39 lambs (30·7%) tested positive for Cryptosporidium by microscopy. PCR products of the SSU rRNA locus were obtained for 27 Cryptosporidium positive calf isolates and 23 lamb isolates. Restriction analyses generated profiles of C. parvum in all isolates except for 9 lamb specimens from 5 farms that yielded banding patterns and sequences indicative of the Cryptosporidium cervine genotype. Sequence analyses of the glycoprotein (GP60) gene revealed that all but 1 C. parvum isolate from calves belonged to the subtype IIaA15G2R1 and 1 isolate was identified as the novel subtype IIaA13G1R1. Two different subtypes were identified in sheep flocks including IIaA16G3R1, which was seen in 7 lamb isolates from a single farm and subtype IIaA15G2R1, identified in 3 isolates from 2 farms. These findings suggest a limited genetic diversity within C. parvum in ruminant livestock from this geographical area, although both calves and lambs should be considered as a reservoir for zoonotic subtypes.

Is Giardia a significant pathogen in production animals?

Although Giardia duodenalis is recognised worldwide as the most important parasitic cause of gastro-intestinal disorder in human patients, the relevance of infection in production animals is prone to debate. Since the 1980s, clinical disease has been associated with giardiasis in production animals, both in natural conditions and in experimental studies. However, most Giardia research is focussed on the relevance of production animals as a reservoir for zoonotic transmission. In this study, the current knowledge on clinical relevance of giardiasis in production animals is reviewed, along with the diagnosis, treatment and control of infection. Furthermore, future research objectives are discussed.

Cryptosporidiumspecies and subtype analysis from dairy calves in Spain

Faecal specimens from 287 diarrhoeic calves younger than 21 days, collected over a 2-year period (2006–2007) from 82 dairy cattle farms in 14 provinces across the north of Spain, were examined for the presence ofCryptosporidiumoocysts. Overall, 63 farms (76·8%) and 166 calves (57·8%) tested positive by microscopy. In order to elucidate the genetic diversity, selected positive specimens from 149 calves originating from 61 farms in the 14 provinces were examined by genotyping and subtyping techniques.Cryptosporidium parvumwas the only species identified by PCR-RFLP of SSU rDNA from all 149 isolates and sequencing of a subset of 50 isolates, except for 2 specimens that were identified asC. bovis. Sequence analyses of the glycoprotein (GP60) gene revealed that mostC. parvumisolates (98%) belonged to the subtype family IIa and 2 isolates were identified as the novel subtype IIdA23G1. Subtype IIaA15G2R1 was the most common and widely distributed (80·3% of the 61 farms), followed by subtype IIaA16G3R1 (14·7%), whereas the remaining IIa subtypes (IIaA16G2R1, IIaA17G2R1, IIaA18G3R1, IIaA19G3R1) were restricted to 1–3 farms. All theseC. parvumIIa subtypes have previously been described in human patients, indicating that most isolates from diarrhoeic calves in northern Spain have zoonotic potential.

A longitudinal study of cryptosporidiosis in dairy cattle from birth to 2 years of age

Fecal specimens were collected from 30 calves from birth to 24 months of age at a dairy farm in Maryland to determine the prevalence and age distribution of Cryptosporidium species/genotypes. After centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy and polymerase chain reaction (PCR). Fragments of the SSU-rDNA gene amplified by PCR were purified and PCR products were sequenced. All 30 calves shed Cryptosporidium oocysts at some time during the 24 months of the study. Of 990 specimens, 190 were Cryptosporidium-positive (19.2%). The highest prevalence of infection was at 2 weeks of age when 29 of the 30 calves were excreting oocysts. Prevalence was higher in pre-weaned calves (1-8 weeks of age) (45.8%) than in post-weaned calves (3-12 months of age) (18.5%) and heifers (12-24 months of age) (2.2%). Sequence data for 190 PCR-positive specimens identified: C. parvum, C. bovis, the Cryptosporidium deer-like genotype and C. andersoni, with cumulative prevalences of 100, 80, 60, and 3.3%, respectively. C. parvum constituted 97% of infections in pre-weaned calves but only 4% and 0% of infections in post-weaned calves and heifers, respectively. All C. parvum GP60 nucleotide sequences were subtype IIaA15G2R1.

Prevalence and risk factors for Cryptosporidium spp. infection in young calves

A cross-sectional study was designed to investigate the prevalence and risk factors for Cryptosporidium infection in young calves. Forty-one farms in a discrete, densely farmed 100 km2 area of North West England were visited over a 3-week period and 215 faecal samples were collected from young calves. Farms were not selected on the basis of existing scour problems. At the time of sampling, several investigator-observed variables were recorded at the pen, animal and stool levels. Samples were screened and 60/215 were confirmed as positive by PCR of the 18S rRNA gene. Risk factors for infection were explored using multilevel multivariable logistic regression with farm as a random effect. Age was significant in the final model, with a higher risk of infection in calves aged 8-21 days, when compared to those aged 0-7 days. The depth of the bedding was also significant in the final model, with calves housed in bedding 11-15 cm deep being at lower risk of infection than those on beds 0-5 cm deep. Consistency of the faeces was highly correlated with age and colour of the faeces and was not significantly associated with infection when these variables, and clustering at farm-level, were accounted for. This is interesting as Cryptosporidium is considered to be a primary enteropathogen. The results suggest that intervention strategies should be targeted at calves under 21 days old. These animals represent a significant reservoir of infection on the farm and may also pose a risk to public health, assuming that the species and genotypes shed are zoonotic pathogens.

Cryptosporidium and dairy cattle in the Catskill/Delaware watershed: a quantitative risk assessment

We carried out a study to estimate the public health risk posed by dairy cattle located in New York City's Catskill/Delaware watershed, as measured by daily C. parvum-like oocyst loading. A Monte Carlo simulation model that takes into account the nature of the dairy cattle population within the target area, age-specific incidence/prevalence rates, as well as differential fecal production and oocyst-shedding intensity rates was used to address the objectives. Additionally, the model was designed to distinguish between zoonotic and nonzoonotic species/genotypes of Cryptosporidium. Total estimated daily C. parvum-like oocyst shedding across all age/production categories was estimated at 4.15 x 10(10). The zoonotic C. parvum comprised 93.5% of this load. It was estimated that preweaned calves produce 99.5% of the total daily C. parvum ocyst burden. The recently described nonzoonotic C. bovis was estimated to have a daily load of 2.2 x 10(9) oocysts across all age/production strata. C. parvum deer-like genotype was estimated to have a total daily load of 1.3 x 10(9) oocysts. The results of this study support earlier assertions that strategies aimed at reducing the cryptosporidial risk posed by dairy cattle to public health will be most efficacious if aimed at preweaned calves.

Prevalence and molecular characterization of Giardia duodenalis and Cryptosporidium spp. in dairy cattle in Ontario, Canada

Giardia duodenalis and Cryptosporidium spp. are intestinal protozoan parasites that infect a wide range of host species, including humans. Molecular characterization of these parasites has demonstrated that a number of genotypes and species are common to both humans and animals, and that zoonotic transmission may occur. Numerous studies have reported a high prevalence of G. duodenalis and Cryptosporidium spp. in cattle, particularly calves, and these animals are frequently associated with zoonotic transmission. In the present study, a total of 143 faecal samples from adults, heifers and calves were collected from two dairy cattle farms in eastern Ontario, Canada. The prevalence and molecular characteristics of G. duodenalis and Cryptosporidium spp. in these animals were determined in order to investigate the potential for transmission between cattle and humans in this region. Following DNA extractions from faecal samples, nested-PCR protocols were used to amplify fragments of the 16S rRNA gene and the heat-shock protein 70 (HSP-70) gene for determining the prevalence of G. duodenalis and Cryptosporidium spp. infections, respectively. Genotypes of G. duodenalis, and species of Cryptosporidium, were determined by means of DNA sequencing of amplicons, and subsequent sequence alignment. Cattle on both farms showed a high prevalence of G. duodenalis (42.0%) and Cryptosporidium spp. (27.3%). G. duodenalis infections were more prevalent in calves and heifers than in adults, and Cryptosporidium spp. infections were only observed in calves and heifers. The zoonotic genotype, G. duodenalis Assemblage B was isolated from 24.5% of the cattle tested, while G. duodenalis Assemblage E was found in 17.5% of the cattle tested. The overall prevalence of the zoonotic species Cryptosporidium parvum in the animals tested was found to be 21.7%, while only 1.4% were infected with C. bovis. These findings suggest that there is a potential risk of zoonotic and/or zooanthroponotic transmission of G. duodenalis and C. parvum infections between cattle and humans in eastern Ontario, likely by means of contaminated water or food, or through direct faecal-oral transmission in the case of farmers and veterinary staff.

Prevalence of Cryptosporidium infection in cattle in Isfahan, Iran

Cryptosporidium are commonly identified as intestinal pathogens in humans and animals. Fecal samples from 480 cattle randomly selected from 30 regions in Isfahan, Iran, were examined to investigate the prevalence of Cryptosporidium infection. Cryptosporidium oocysts were identified by using sheather's concentration and the Ziehl-Neelsen modified staining technique in 30 of 480 cattle ranging from less than 6 mo of age to older than 1 yr of age. Infected animals were found in 86.6% (26/30) of regions investigated. Overall prevalence of infection was 6.25%, but higher in cattle less than 6 mo of age (10.8%) and this was statistically significant (P<0.05). Both sexes of cattle were infected with Cryptosporidium parasites, but prevalences were higher in diarrheic (56.7%) than in non-diarrheic (39%) cattle. Cryptosporidium appears to be prevalent in cattle in Isfahan.

Genetic characterization of Cryptosporidium species from humans in Spain

Several species of Cryptosporidium have been associated with infection. Cryptosporidium parvum and Cryptosporidium hominis are the main agents of cryptosporidiosis in humans. Stool samples from 108 Cryptosporidium-infected patients were submitted to PCR-RFLP analysis for a 553-bp fragment of Cryptosporidium oocyst wall protein (COWP) gene and an 826-864 bp fragment of the small-subunit ribosomal RNA (SSU-rRNA) gene. Ninety-two patients were immunocompetent children and 16 were HIV-infected adults. C. hominis was detected in 69 patients (59 immunocompetent and 10 HIV-infected); C. parvum, in 34 patients (28 immunocompetent and 6 HIV-infected); and C. meleagridis and C. felis in one patient each (both immunocompetent children). Three samples yielded negative results. C. parvum was significantly more frequent in children from rural areas than in those of urban residence (p=0.010). As far as we know, this is the first surveillance study about the molecular characterization of Cryptosporidium in humans performed in Spain. The finding of zoonotic species infecting humans calls for further research on this subject.

Presence of Giardia cysts and Cryptosporidium oocysts in drinking water supplies in northern Spain

AIMS

To evaluate the prevalence of Cryptosporidium and Giardia in surface water supplies from the province of Alava, northern Spain, and to investigate possible associations among the presence of these pathogenic protozoa with microbiological, physicochemical and atmospheric parameters.

METHODS AND RESULTS

A total of 284 samples of drinking and recreational water supplies were analysed. Cryptosporidium oocysts were found in 63.5% of river samples, 33.3% of reservoirs samples, 15.4% and 22.6% of raw water samples from conventional and small water treatment facilities (respectively), 30.8% of treated water from small treatment facilities, and 26.8% of tap water from municipalities with chlorination treatment only. Giardia cysts were found in 92.3% of river samples, 55.5% of reservoirs samples, 26.9% and 45.2% of raw water samples from conventional and small water treatment facilities (respectively), 19.2% of treated water from small treatment facilities, and 26.8% of tap water from municipalities with chlorination treatment only. The presence of Cryptosporidium and Giardia had significant Pearson's correlation coefficients (P < 0.01) with the turbidity levels of the samples, and a number of significant associations were also found with the count levels for total coliforms and Escherichia coli. The samples were positive for Cryptosporidium significantly (P < 0.05) more frequently during the autumn season than during the spring and winter seasons. No significant differences were found in the seasonal pattern of Giardia. A moderate association (r = 0.52) was found between rainfall and the presence of Cryptosporidium oocysts.

CONCLUSIONS

Cryptosporidium and Giardia are consistently found at elevated concentrations in surface waters for human consumption from the province of Alava, northern Spain.

SIGNIFICANCE AND IMPACT OF THE STUDY

Water treatments based on rapid filtration process and/or chlorination only are often unsatisfactory to provide safe drinking water, a situation that represents an important public health problem for the affected population because of the risk of waterborne outbreaks.

Giardia and Cryptosporidium in water buffaloes (Bubalus bubalis)

A cross-sectional survey of Giardia duodenalis and Cryptosporidium parvum infection in the water buffalo (Bubalus bubalis) was carried out in central Italy. A geographical information system (GIS) was constructed utilizing as data-layers the topographic base map and the digital aerial photographs of the study area, as well as the geo-referenced points of all the buffalo farms. The survey was conducted on a sample of 90 farms, selected using a grid approach followed by proportional allocation. For this purpose, a grid representing quadrants of 5 x 5 km was overlaid on the study area within the GIS. As a result, the study area was divided in equal quadrants, and the number of farms sampled in each quadrant was proportional to the total number of study population in that quadrant. On each farm, faecal samples were collected per rectum from three to five asymptomatic buffalo calves, aged from 1 to 9 weeks. The total number of faecal samples collected was 347. Each faecal sample was tested for the presence of copro-antigens of G. duodenalis and of C. parvum using two commercially available enzyme-linked immunosorbent assays. Out of the 90 farms, 27 (30.0%) resulted positive for G. duodenalis and 22 (24.4%) for C. parvum. Co-infection was found in ten (11.1%) farms. With respect to animals, out of the 347 faecal samples, 63 (18.1%) were found to have antigens of G. duodenalis and 51 (14.7%) of C. parvum. Co-infection was found in ten buffalo calves (2.9%). The results of the logistic regression models showed a positive association between the positivity to G. duodenalis and the presence of sheep on farm and between the positivity to C. parvum and the high number of buffaloes on farms. No significant co-infection between the two protozoa was found. In conclusion, the findings of the present study, derived from a systematic territorial survey planned with GIS, are noteworthy because they provided additional data on C. parvum and the first evidence of G. duodenalis infection in water buffaloes.

Cryptosporidium infection in domestic geese (Anser anser f. domestica) detected by in-situ hybridization

An in-situ hybridization (ISH) procedure was developed for the detection of Cryptosporidium sp. in paraffin wax-embedded tissues with a digoxigenin-labelled probe targeting the 18S rRNA. This technique was used in addition to traditional methods, such as haematoxylin and eosin staining, periodic acid-Schiff reaction, transmission electron microscopy and the polymerase chain reaction, to examine the bursa of Fabricius (BF), conjunctiva and other tissues from 20 domestic geese aged 16-36 days for the presence of cryptosporidia. Positive signals were found to a moderate or marked extent in both conjunctival samples (89%) and BF samples (88%) but not in other tissues. Sequencing of the PCR amplification product revealed identity with Cryptosporidium baileyi. The infected geese showed no clinical signs and only scanty histological lesions. These results confirm reports showing that young waterfowl are especially vulnerable to cryptosporidium infection and indicate that the BF and conjunctiva are the preferred sites for the presence of the protozoon. ISH proved a good method for detecting and identifying even small numbers of cryptosporidia in tissue sections.

A Bayesian approach for the evaluation of six diagnostic assays and the estimation ofCryptosporidiumprevalence in dairy calves

The prevalence of Cryptosporidium in calves and the test properties of six diagnostic assays (microscopy (ME), an immunofluorescence assay (IFA), two ELISA and two PCR assays) were estimated using Bayesian analysis. In a first Bayesian approach, the test results of the four conventional techniques were used: ME, IFA and two ELISA. This four-test approach estimated that the calf prevalence was 17% (95% Probability Interval (PI): 0.1-0.28) and that the specificity estimates of the IFA and ELISA were high compared to ME. A six-test Bayesian model was developed using the test results of the 4 conventional assays and 2 PCR assays, resulting in a higher calf prevalence estimate (58% with a 95% PI: 0.5-0.66) and in a different test evaluation: the sensitivity estimates of the conventional techniques decreased in the six-test approach, due to the inclusion of two PCR assays with a higher sensitivity compared to the conventional techniques. The specificity estimates of these conventional assays were comparable in the four-test and six-test approach. These results both illustrate the potential and the pitfalls of a Bayesian analysis in estimating prevalence and test characteristics, since posterior estimates are variables depending both on the data at hand and prior information included in the analysis. The need for sensitive diagnostic assays in epidemiological studies is demonstrated, especially for the identification of subclinically infected animals since the PCR assays identify these animals with reduced oocyst excretion, which the conventional techniques fail to identify.

Prevalence of Giardia and Cryptosporidium in dairy calves in three areas of Norway

A study was undertaken to determine the prevalences of Cryptosporidium and Giardia in dairy calves less than 6 months of age in Norway. Faecal samples were collected from a total of 1386 calves, between 3 and 183 days of age, in 136 dairy farms from three different areas of Norway. Faecal samples were examined for Cryptosporidium oocysts and Giardia cysts after concentration and immunofluorescent staining. Giardia was found in 93% (127 out of 136) of the farms and in 49% (679 out of 1386) of the calves. Cryptosporidium was found in 53% (72 out of 136) of the farms and in 12% (167 out of 1386) of the calves. The level of Giardia and/or Cryptosporidium was low in the majority of the infected calves. Infection peaked in the age group 2-3 months for both Cryptosporidium and Giardia. The prevalences of both parasites were higher in samples taken during winter than in samples taken during summer, and statistically significant differences were found when prevalences in different age groups of calves were compared between the three areas. A significantly lower prevalence of Cryptosporidium was found in calves housed in shared pens that were thoroughly washed more than three times a year than in calves from pens washed less often. For Giardia there was a trend for decreasing intensity of infection with increasing age in the sampled calves. For Cryptosporidium there was a trend for increasing herd prevalence with increasing number of calves in the herd, but this trend was not statistically significant. Other parameters which were investigated such as housing, feeding or management routines were not associated with prevalence or intensity of infection with either parasite.

Environmental load of Cryptosporidium parvum oocysts from cattle manure in feedlots from the central and western United States

The first step in assessing the risk of water contamination by Cryptosporidium parvum oocysts from feedlot cattle (Bos taurus) production systems is to quantify the number of C. parvum oocysts present in the fecal material deposited by feedlot cattle. Our primary objective for this project was to estimate the daily environmental load of C. parvum oocysts in fecal material deposited by feedlot cattle from across the central and western USA. Our secondary goal was to genotype isolates of C. parvum from feedlot cattle to help facilitate proper identification of mammalian sources of waterborne C. parvum. Based on 5274 fecal samples from 22 feedlots in seven states (California, Washington, Colorado, Oklahoma, Texas, Nebraska, and South Dakota), we estimated a point prevalence of C. parvum of 0.99 to 1.08% in fecal material from feedlot pens from a wide range of climates and a diverse range of feedlot management systems. On average, fresh fecal material from throughout feedlot systems (recent arrivals to nearing slaughter) contained about 1.3 to 3.6 oocysts/g feces, which roughly translates to about 2.8 x 10(4) to 1.4 x 10(5) oocysts/animal per day.

Prevalence of species and genotypes of Cryptosporidium found in 1–2-year-old dairy cattle in the eastern United States

The prevalence of Cryptosporidium species in 1-2-year-old heifers was determined for 571 animals on 14 dairy farms in seven states on the East Coast of the United States. A fecal specimen collected directly from each heifer was processed to concentrate oocysts that were then examined by polymerase chain reaction (PCR). For every PCR-positive specimen the 18S rRNA gene of Cryptosporidium was sequenced. Cryptosporidium was identified by PCR from heifers on 13 of 14 farms. On all except four farms groups of heifers were housed in a barn or in large covered pens. Others were pastured. From many of the same farms an earlier study reported that 41% of 393 pre-weaned calves and 26.2% of 447 post-weaned calves were infected. In the present study, 11.9% of 571 heifers were infected with Cryptosporidium, 0.7% with Cryptosporidium parvum, the zoonotic species. Of 68 PCR-positive specimens characterized by gene sequencing 1, 4, 10, 24, and 29 calves were infected with Cryptosporidium suis, Cryptosporidium parvum, Cryptosporidium deer-like genotype, Cryptosporidium bovis, and Cryptosporidium andersoni, respectively. These findings demonstrate a lower prevalence of infection in 1-2-year-old dairy cattle than in younger cattle as well as a change in the diversity of species present. Consequently, the risk of humans acquiring infection with C. parvum from exposure to feces from yearling and older cattle appears much lower than from exposure to pre-weaned calves.

The occurrence of Cryptosporidium parvum, Campylobacter and Salmonella in newborn dairy calves in the Manawatu region of New Zealand

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.

Endoparasites in calves of beef cattle herds: management systems dependent and genetic influences

Prevalences and intensities of excretion of faecal stages of Giardia duodenalis, Cryptosporidium parvum, Eimeria spp., Strongyloides papillosus and strongyles were determined in a German upland area in German Angus (GA) and German Simmental (GS) suckler of beef cattle herds covering two winter housing periods and the grazing season between them. Influences of the housing systems applied (maintenance on deep litter with (DL+) and without run-out (DL--), on slatted floor (SF) or by winter run-out yarding (WO)), breed differences and genetic influences by the sire were determined by statistical analyses; levels of IgG antibodies to E. bovis antigen were measured by ELISA. G. duodenalis was observed with a maximum prevalence of 38% in 4 weeks old calves, a cumulative incidence of 58% 9 weeks after birth and with generally low intensities. C. parvum infections were relatively rare with cumulative incidences of 20--25% in week 5 after birth. Highest prevalences were associated with housing system DL-- and a long-lasting calving period. Cumulative incidence of Eimeria spp. was almost 100%. E. bovis predominated by far followed by E. ellipsoidalis/zuernii. Mean maximum intensity of 1000 OpG occurred in week 7 after birth. Up to an age of the calves of 7 weeks >75% of all oocysts belonged to E. bovis. Prevalences and excretion intensities were lowest under the housing conditions SF and WO. Maternal antibodies in calves to E. bovis antigen were directly and inversely correlated with mean OpG values in GA and GS calves, respectively. S. papillosus was common with a cumulative incidence of 53% 9 weeks after birth and occurred independent of the housing system. Mean strongyle egg prevalence was 50% with 50--100 EpG by means throughout the grazing season. Egg excretion intensity in the early months of grazings was correlated with the age of the calves at turnout to pasture. Under the conditions of housing system DL-- GA calves could better control S. papillosus infections than GS calves whereas the latter were generally more effective in controlling the protozoa. Results of ANCOVA suggest significant paternal influences on S. papillosus infections in both breeds and on the protozoal infections in GA calves. The former could be disclosed independent of the housing system whereas environmental factors played an important role in the latter cases.

Prevalence and characterisation of Cryptosporidium species in cattle faeces and on beef carcases at slaughter

Cattle are known reservoirs and asymptomatic excretors of Cryptosporidium, a protozoan parasite that causes severe and protracted diarrhoea in people. The incidence of Cryptosporidium was investigated in 288 matched samples taken from beef carcases of 1 g samples of faeces retrieved immediately after de-legging, 25 cm2 samples of beef excised from the rump of uneviscerated carcases, and 25 cm2 samples of beef excised from the brisket area of eviscerated carcases. Cryptosporidium species were detected in 21 of the faecal samples after salt flotation and immunofluorescent microscopy. The species isolated from the positive samples were identified by restriction fragment length polymorphism and PCR as Cryptosporidium andersoni (54.5 per cent) and Cryptosporidium parvum genotype 2 (45.5 per cent). In the faecal samples, there was a significantly higher prevalence of the parasite in samples taken in summer (May to July) and winter (November to January) than in spring or autumn. No Cryptosporidium species were recovered from any of the beef samples.

Estimation of diagnostic test characteristics and prevalence of Giardia duodenalis in dairy calves in Belgium using a Bayesian approach

A Bayesian approach was used to determine both the test properties of three diagnostic test procedures and the prevalence of Giardia duodenalis in dairy calves in Belgium. A cross-sectional survey was conducted in the province of East Flanders, Belgium. Between September 2001 and December 2003, a total of 100 farms were visited and faecal samples were obtained rectally from 499 calves aged from newborn to 70 days. Because there is no gold standard for the diagnosis of a G. duodenalis infection in dairy calves, a subset of 235 samples obtained on the first 50 farms, was examined using three different assays: microscopical examination, an immunofluorescence assay (IFA) and an antigen detecting Elisa (ELISA). Based on the results of these three tests, Bayesian analysis indicated that the prevalence of G. duodenalis in dairy calves was 0.19 (95% Confidence Interval: 0.11-0.28) and that ELISA (Sensitivity (Se) 0.89 and Specificity (Sp): 0.90) and IFA (Se: 0.77 and Sp: 0.95) were both sensitive and specific diagnostic techniques, whereas microscopical examination was less sensitive (Se: 0.56 and Sp: 0.87). The proportion of positive farms was estimated as 0.42 (0.24-0.62). The prevalence and the cyst excretion in calves from different age categories were based on data obtained by IFA on all 499 samples. The prevalence was highest among four to five week old calves and remained high among older calves up to 10 weeks, but was lower among calves before the age of two weeks. The number of excreted cysts was estimated by IFA and ranged from 100 to 1,040,000 cysts per gram faeces, with a mean of 3516 cysts per gram faeces. The intensity of excretion peaked among four-week-old calves and remained high among calves up to the age of eight weeks. This is the first known study to use Bayesian analysis to estimate the prevalence of G. duodenalis in the faeces of dairy calves and to estimate test characteristics of diagnostic assays used for the detection of G. duodenalis.

Estimating potential environmental loadings of Cryptosporidium spp. and Campylobacter spp. from livestock in the Grand River Watershed, Ontario, Canada

Exposure to waterborne pathogens in recreational or drinking water is a serious public health concern. Thus, it is important to determine the sources of pathogens in a watershed and to quantify their environmental loadings. The natural variability of potentially pathogenic microorganisms in the environment from anthropogenic, natural, and livestock sources is large and has been difficult to quantify. A first step in characterizing the risk of nonpoint source contamination from pathogens of livestock origin is to determine the potential environmental loading based on animal prevalence and fecal shedding intensity. This study developed a probabilistic model for estimating the production of Cryptosporidium spp. and Campylobacter spp. from livestock sources within a watershed. Probability density functions representing daily pathogen production rates from livestock were simulated for the Grand River Watershed in southwestern Ontario. The prevalence of pathogenic microorganisms in animals was modeled as a mixture of beta-distributions with parameters drawn from published studies. Similarly, gamma-distributions were generated to describe animal pathogen shedding intensity. Results demonstrate that although cattle are responsible for the largest amount of manure produced, other domesticated farm animals contribute large numbers of the two pathogenic microorganisms studied. Daily pathogen production rates are highly sensitive to the parameters of the gamma-distributions, illustrating the need for reliable data on animal shedding intensity. The methodology may be used for identifying source terms for pathogen fate and transport modeling and for defining and targeting regions that are most vulnerable to water contamination from pathogenic sources.

Prevalence and age-related variation of Cryptosporidium species and genotypes in dairy calves

Fifteen dairy farms in seven states on the east coast of the US were each visited on two consecutive years to determinate the prevalence of Cryptosporidium species in pre-weaned (5 days to 2 months) and post-weaned calves (3-11 months), respectively. After each of 971 fecal specimens collected directly from each calf was sieved and subjected to density gradient centrifugation to remove debris and concentrate oocysts, specimens were examined by immunofluorescence microscopy, and polymerase chain reaction (PCR). For all PCR-positive specimens the 18S rRNA gene of Cryptosporidium was sequenced. Cryptosporidium was identified from all farms. Types of housing appeared to have no influence with regard to prevalence of infection. Of 971 calves, 345 were infected with Cryptosporidium (35.5%), but more pre-weaned calves (253 of 503; 50.3%) than post-weaned calves (92 of 468; 19.7%) were found to be infected. A total of 278 PCR-positive specimens characterized by gene sequencing revealed Cryptosporidium parvum, Cryptosporidium andersoni, and two unnamed Cryptosporidium genotypes Bovine B (AY120911) and deer-like genotype (AY120910). The prevalence of these Cryptosporidium species and genotypes appeared to be age related between pre- and post-weaned calves. C. parvum, the only zoonotic species/genotype, constituted 85% of the Cryptosporidium infections in pre-weaned calves but only 1% of the Cryptosporidium infections in post-weaned calves. These findings clearly demonstrate that earlier reports on the presence and prevalence of C. parvum in post-weaned cattle that were based solely on oocyst morphology must be reassessed using molecular methods to validate species and genotype. This finding also indicates that persons handling or otherwise exposed to calves under 2 months of age are at greater risk of zoonotic infection from Cryptosporidium than the risk of infection from exposure to older calves.

Improved quantitative estimates of low environmental loading and sporadic periparturient shedding of Cryptosporidium parvum in adult beef cattle

Our primary goal was to generate an accurate estimate of the daily environmental loading rate of Cryptosporidium parvum oocysts for adult beef cattle, using immunomagnetic separation coupled with direct immunofluorescence microscopy for a highly sensitive diagnostic assay. An additional goal was to measure the prevalence and intensity of fecal shedding of C. parvum oocysts in pre- and postparturient cows as an indicator of their potential to infect young calves. This diagnostic method could detect with a > or = 90% probability oocyst concentrations as low as 3.2 oocysts g of feces(-1), with a 54% probability of detecting just one oocyst g of feces(-1). Using this diagnostic method, the overall apparent prevalence of adult beef cattle testing positive for C. parvum was 7.1% (17 of 240), with 8.3 and 5.8% of cattle shedding oocysts during the pre- and postcalving periods, respectively. The mean intensity of oocyst shedding for test-positive cattle was 3.38 oocysts g of feces(-1). The estimated environmental loading rate of C. parvum ranged from 3,900 to 9,200 oocysts cow(-1) day(-1), which is substantially less than a previous estimate of 1.7 x 10(5) oocysts cow(-1) day(-1) (range of 7.7 x 10(4) to 2.3 x 10(5) oocysts cow(-1) day(-1)) (B. Hoar, E. R. Atwill, and T. B. Farver, Quant. Microbiol. 2:21-36, 2000). Use of this highly sensitive assay functioned to detect a greater proportion of low-intensity shedders in our population of cattle, which reduced the estimated mean intensity of shedding and thereby reduced the associated environmental loading rate compared to those of previous studies.

Prevalence of Giardia spp. and Cryptosporidium spp. on dairy farms in southeastern New York state

A prevalence study was designed to determine the presence of Cryptosporidium spp. and Giardia spp. in the soil of 37 dairy farms in southeastern New York state. A sampling design was developed and used to collect soil samples from these farms. Areas on the farms which were considered to be potential sources of contamination to the environment were evaluated quantitatively using a multidimensional scale. This scale included factors which could have the potential to contribute to the risk of contamination of the environment with Giardia or Cryptosporidium. In addition, the runoff pathway from these areas was identified and sampling points along that pathway were determined. Using a sampling grid, sampling sites were determined and soil samples collected and analyzed individually for the following: presence of Giardia and Cryptosporidium, pH, gravimetric moisture content, and volumetric moisture content. Out of 782 soil samples, 17% were positive for Cryptosporidium and 4% were positive for Giardia. The pH of the soil ranged from 3.7 to 9.8 with a mean of 7.0. There was a significant association between the pH and the likelihood of detecting Cryptosporidium spp. As the pH increased, the likelihood of detecting an oocyst decreased. Gravimetric moisture content had a mean of 40% and a range from 7 to 86%. There was a significant association between the gravimetric moisture content and the likelihood of detecting Giardia in soil samples.