Prevalence of Cryptosporidium, Giardia and Eimeria infections in post-weaned and adult cattle on three Maryland farms

Update on transmission of zoonotic Giardia in cattle

Giardia is the most common protozoan cause of diarrhoeal illness in humans worldwide. Despite this, our understanding of the zoonotic transmission of Giardia, and in particular the role of cattle as a zoonotic reservoir, is not well understood, due to the limitations of current typing systems and a recent taxonomic revision of the genus. Newly improved multilocus sequencing typing tools are not yet widely used and are not applicable to all species. However, data generated to date suggest that zoonotic transmission of Giardia of bovine origin is limited. Carefully designed epidemiological investigations using improved typing tools are essential to understand the extent of zoonotic transmission from cattle. Improved on-farm biosecurity measures are also needed to control the transmission of zoonotic Giardia in cattle.

Molecular detection and characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi infections in dromedary camels (Camelus dromedaries) in Egypt

Introduction

Few studies have investigated the occurrence of microeukaryotic gut parasites in dromedary camels in Egypt, and the majority of these investigations are based on microscopic analysis of fecal material.

Methods

Herein, we assessed the occurrence, molecular diversity, and zoonotic potential of protozoan (Cryptosporidium spp. and Giardia duodenalis) and microsporidian (Enterocytozoon bieneusi) pathogens in individual fecal samples (n = 102) of dromedary camels with (n = 26) and without (n = 76) diarrhea from Aswan Governorate, Upper Egypt. Other factors possibly associated with an increased risk of infection (geographical origin, sex, age, and physical condition) were also analyzed. The SSU rRNA or ITS genes were targeted by molecular (PCR and Sanger sequencing) techniques for pathogen detection and species identification.

Results and discussion

The most abundant species detected was G. duodenalis (3.9%, 4/102; 95% CI: 1.1-9.7), followed by Cryptosporidium spp. (2.9%, 3/102; 95% CI: 0.6-8.4). All samples tested negative for the presence of E. bieneusi. Sequence analysis data confirmed the presence of zoonotic C. parvum (66.7%, 2/3) and cattle-adapted C. bovis (33.3%, 1/3). These Cryptosporidium isolates, as well as the four Giardia-positive isolates, were unable to be amplified at adequate genotyping markers (Cryptosporidium: gp60; Giardia: gdh, bg, and tpi). Camels younger than 2 years old were significantly more likely to harbor Cryptosporidium infections. This connection was not statistically significant, although two of the three cryptosporidiosis cases were detected in camels with diarrhea. The spread of G. duodenalis infections was unaffected by any risk variables studied. This is the first report of C. parvum and C. bovis in Egyptian camels. The finding of zoonotic C. parvum has public health implications since camels may function as sources of oocyst pollution in the environment and potentially infect livestock and humans. Although preliminary, this study provides useful baseline data on the epidemiology of diarrhea-causing microeukaryotic parasites in Egypt. Further research is required to confirm and expand our findings in other animal populations and geographical regions of the country.

Investigation of giardiasis in captive animals in zoological gardens with strain typing of assemblages in China

Giardia duodenalis is a common zoonotic intestinal pathogen. It has been increasingly reported in humans and animals; however, genotyping information for G. duodenalis in captive animals is still limited. This study was conducted to assess the prevalence and multilocus genotyping of G. duodenalis in captive animals in zoological gardens in Shanghai, China. A total of 678 fresh fecal samples were randomly collected from captive animals including non-human primates (NHPs) (n = 190), herbivores (n = 190), carnivores (n = 151), birds (n = 138) and reptiles (n = 9) in a zoo and were examined for the presence of G. duodenalis using nested polymerase chain reaction (nested PCR). All G. duodenalis positive samples were assayed with PCR followed by sequencing at β-giardin (bg), glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) genes. In this study, 42 specimens (6.2%) were tested G. duodenalis-positive of the 678 fecal samples examined based on a single locus. A total of 30 (4.4%), 30 (4.4%) and 22 (3.2%) specimens were successfully amplified and sequenced at gdh, tpi and bg loci, respectively. Assemblages A and B were identified with assemblage B dominating in NHPs. Sequence analysis demonstrated that one, two and five new isolates were identified at bg, gdh and tpi loci. DNA sequences and new assemblage-subtypes of zoonotic G. duodenalis assemblages A and B were identified in the current study. Our data indicate the occurrence and molecular diversity of G. duodenalis and the potential zoonotic transmission in captive animals in China.

Cryptosporidiosis and Giardiasis in Buffaloes (Bubalus bubalis)

Cryptosporidium spp. and Giardia duodenalis infect the gastrointestinal tracts of animals and humans. Both parasite groups are distributed worldwide and cause significant economic losses in animal productivity. Infected hosts presenting with and without clinical manifestations can eliminate infective forms of these protozoa, which are particularly important to One Health. Compared to the published research on cattle, relatively few studies have examined the epidemiology of cryptosporidiosis and giardiasis in buffaloes. This short review describes the global occurrence of Cryptosporidium spp. and G. duodenalis in buffaloes, including the molecular techniques employed for the identification of species/assemblages and genotypes of these protozoa. Genetic analyses of isolates of G. duodenalis and Cryptosporidium spp. from various sources (environmental, animal, and human) have been performed to investigate their epidemiology. In buffaloes, the species Cryptosporidium parvum, Cryptosporidium ryanae, Cryptosporidium bovis, and Cryptosporidium suis-like have been characterized, as well as assemblages A and E of G. duodenalis. We demonstrate that buffaloes can be infected by species of Cryptosporidium spp. and G. duodenalis assemblages with zoonotic potential. Epidemiological studies that utilize molecular biology techniques represent an important resource for efforts to control and prevent the spread of these protozoans.

Preweaned heifer management on US dairy operations: Part I. Descriptive characteristics of preweaned heifer raising practices

The objective of this study was to describe preweaned dairy heifer calf management practices on dairy operations across the United States that were used to analyze factors associated with colostrum quality and passive transfer, Cryptosporidium and Giardia, morbidity and mortality, and average daily gain. This study included 104 dairy operations in 13 states that participated in the National Animal Health Monitoring System's Dairy 2014 calf component study. This 18-mo longitudinal study focused on dairy heifer calves from birth to weaning, and data were collected on 2,545 heifer calves. Descriptive statistics were generated regarding colostrum feeding, preweaning housing, milk feeding and consumption, growth, morbidity and mortality, and weaning practices. The majority of calves enrolled were Holsteins (89.4%). Over half the calves (63.2%) enrolled in the study received the majority of their colostrum via bottle; however, 22.1% of calves from 51.0% of operations received colostrum via suckling from their dams. For all calves, the mean time to the first colostrum feeding was 2.8 h, and the average amount of colostrum at the first feeding was 2.9 L, with 4.5 L provided in the first 24 h. The mean serum IgG of all calves was 21.7 g/L; however, 76.0% of operations had at least 1 calf with failure of passive transfer of immunity with a serum IgG below 10 g/L. The majority of calves in the study were housed individually (86.6%). Nonetheless, 20.2% of operations housed some calves in groups, representing 13.4% of all calves. Approximately one-half of the calves in the study (52.3%) were dehorned or disbudded during the preweaning period, with only 27.8% of these calves receiving analgesics or anesthetics during the procedure. Whole or waste milk was the liquid diet type fed to 40.1% of calves, and milk replacer was fed to 34.8% of calves. A combination of milk and milk replacer was fed to 25.1% of calves. Calves, on average, were fed 2.6 L per feeding and fed 2.6 times/d, resulting in a total of 5.6 L of liquid diet fed per day. The mean average daily gain for all calves enrolled in the study was 0.7 kg/d. Fecal samples were collected and almost all operations had at least 1 calf positive for Cryptosporidium (94.2%) or Giardia (99.0%), and 84.6% of operations had calves that tested positive for both Cryptosporidium and Giardia. Over one-third of calves (38.1%) had at least one morbidity event during the preweaning period and the mortality rate was 5.0%. The mean age at weaning was 65.7 d. This study provides an update on dairy heifer raising practices in the United States.

High genetic diversity of Giardia duodenalis assemblage E in pre-weaned dairy calves in Shanghai, China, revealed by multilocus genotyping

Giardia duodenalis is a common parasitic protozoan in human and animals. Epidemiological and molecular data are available from dairy cattle in many industrialized countries, but information on genetic diversity at multiple genetic loci is limited, especially in pre-weaned dairy calves. In this study, 818 fecal specimens were collected from five dairy cattle farms located in suburbs of Shanghai, China, with two to five samplings per farm. G. duodenalis assemblages and subtypes were determined using multilocus genotyping (MLG) at the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) loci. The overall prevalence was 60.1% (492/818) combining data from the three genetic loci. Three G. duodenalis assemblages were detected, including E (n = 482), A (n = 5), and B (n = 1), with the concurrence of A and E in a few animals (n = 4). Intra-genotypic sequence diversity was high for assemblage E, showing 12, 13, and 17 subtypes at the bg, gdh, and tpi loci, including four, six, and eight new subtypes, respectively. All dominant subtypes (E3, E2, and E8 at the bg locus; E1 and E3 at the gdh locus; and E11 and E3 at the tpi locus) were detected on all farms at most sampling occasions, and only limited differences in subtype distribution were observed among five farms. Altogether, 58 assemblage E MLGs were identified, all of which had not been reported before, and seven (MLG-E1-MLG-E7) were each seen on multiple farms. These results indicate a high occurrence of G. duodenalis in dairy calves, the existence of high genetic heterogeneity of assemblage E on five farms, and frequent exchange of parasite populations among farms within a small geographic area. The clinical and epidemiologic significance of these observations warrants further investigations.

Evaluation of simple diffusion chlorinators for decontamination of wells in a rural settlement in Amazonia, Brazil

While the Amazon region has the world's largest reserve of fresh water, the lack of water services and water treatment, especially in non-urban regions, causes environmental and health problems. In isolated rural settlements supply is usually by shallow wells, and the quality of water is a concern for residents. These are situations where there are restricted options for water treatment. This study aimed to assess the use of simplified diffusion chlorinators as an alternative water treatment method. Bacteriological analyses were made of 100 samples of water from the wells, before and after application of the chlorinators, in the Rural Settlement of Rio Pardo, Presidente Figueiredo in the Brazilian State of Amazonas. The sources that were analyzed were considered inappropriate for consumption without prior treatment, and the use of the chlorinators eliminated all contamination by thermotolerant coliforms in the great majority of cases. Also, the method was well received by residents, because it does not leave a taste in the water, is relatively low-cost and handling is easy. We discuss the advantages and limitations of the use of this method of treatment for this social-environmental context and present suggestions for improvement and adaptation, for application of this methodology in other settlements.

Prevalence and analysis of associated risk factors for Cryptosporidium infection in lambs in Jammu district

An epidemiologic study was carried out to investigate the prevalence and analysis of risk of Cryptosporidium infection in lambs in Jammu district. Faecal samples of 120 lambs of different age groups viz., <1 month, 1-3 months and 3-6 months were assessed. Cryptosporidium oocysts were identified by using modified Zeihl Neelsen technique. Statistical analysis showed that infection rates were significantly higher in lambs of <1 month age group (65 %) than other two age groups (p < 0.05). Similarly, cryptosporidial infection rates were significantly higher in diarrhoeic (54.41 %) than in non diarrhoeic lambs (34.61 %). Winter records highest prevalence (73.33 %) which varied significantly. Sex wise higher prevalence was observed in females (51.56 %) as compared to males (39.28 %). The relationship between intensity of infection and various epidemiological factors showed that highest intensity was observed in lambs of 0-1 month age group, having diarrhoea, in winter season.

First molecular characterisation of Cryptosporidium and Giardia from Bubalus bubalis (water buffalo) in Victoria, Australia

We conducted a molecular epidemiological survey of Cryptosporidium and Giardia from Bubalus bubalis (water buffalo) on two extensive farms (450 km apart) in Victoria, Australia. Faecal samples (n=476) were collected from different age groups of water buffalo at two time points (six months apart) and tested using a PCR-based mutation scanning-targeted sequencing-phylogenetic approach, employing markers within the small subunit of ribosomal RNA (designated pSSU) and triose phosphate isomerase (ptpi) genes. Based on pSSU data, Cryptosporidium parvum, Cryptosporidium bovis and Cryptosporidium genotypes 1, 2 (each 99% similar genetically to Cryptosporidium ryanae) and 3 (99% similar to Cryptosporidium suis) were detected in two (0.4%), one (0.2%), 38 (8.0%), 16 (3.4%) and one (0.2%) of the 476 samples tested, respectively. Using ptpi, Giardia duodenalis assemblages A and E were detected in totals of 56 (11.8%) and six (1.3%) of these samples, respectively. Cryptosporidium was detected on both farms, whereas Giardia was detected only on farm B, and both genera were detected in 1.5% of all samples tested. The study showed that water buffaloes on these farms excreted C. parvum and/or G. duodenalis assemblage A, which are consistent with those found in humans, inferring that these particular pathogens are of zoonotic significance. Future work should focus on investigating, in a temporal and spatial manner, the prevalence and intensity of such infections in water buffaloes in various geographical regions in Australia and in other countries.

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.

Occurrence of Cryptosporidium and Giardia on beef farms and water sources within the vicinity of the farms on Prince Edward Island, Canada

The objectives of this study were to determine the prevalence and assemblages of Giardia and species of Cryptosporidium on beef farms in Prince Edward Island (PEI), Canada, including the water sources associated with the farms, and to determine risk factors for infection of cattle with these parasites. Twenty beef farms were selected based on the presence of surface water< 500 m from the barn. Prevalence was determined by direct immunofluorescence microscopy, while genotyping and species determination were performed by nested-PCR and DNA sequencing. Giardia was detected in 42% (95% CI: 38-46%) of fecal samples from 100% farms while Cryptosporidium was detected in 17% (95% CI: 14-19%) of fecal samples from 80% of farms. The most predominant Giardia assemblage isolated was the livestock specific assemblage E (89%). The zoonotic assemblages A and B were found in 4 and 7% of the Giardia isolates that were genotyped, respectively. The Giardia assemblages were detected equally between the cows and calves examined. Overall, the most common Cryptosporidium species detected in this study was Cryptosporidium andersoni (49%), predominantly found in cattle > 6 mo of age, while most Cryptosporidium bovis and Cryptosporidium pestis (previously Cryptosporidium parvum 'bovine genotype') isolates were detected in calves ≤ 6 mo of age. All Cryptosporidium ryanae isolates (four) were found in calves. Giardia cysts and Cryptosporidium oocysts were detected in 14 and 93% of surface water samples of 14 farms, respectively. Cryptosporidium oocysts were detected in three (15%) ground water samples of 20 farms. One Cryptosporidium-positive water sample, which was the only surface water sample amenable to genotyping, contained C. parvum. The farm-level risk factors investigated in this study, age of animals and location of the farm, were not associated with the risk of infection in cattle with either Cryptosporidium spp. or Giardia duodenalis. We conclude that beef cattle are a potential reservoir of Cryptosporidium spp. and G. duodenalis that could contaminate source water. There is the possibility of further transmission to humans on PEI if the source water is not properly treated prior to consumption.

Modelling Cryptosporidium oocysts transport in small ungauged agricultural catchments

Cryptosporidium is an environmentally robust pathogen that has caused severe waterborne disease outbreaks worldwide. The main source of zoonotic Cryptosporidium parvum oocysts in human drinking water is likely to be from farm animals via catchment pathways with water as the main transport vector. The vast majority of small agricultural catchments are ungauged therefore it is difficult to use a process model to predict and understand the mechanisms and activities that regulate the risk of surface water contamination from agricultural areas. For this study, two ungauged agricultural catchments in Ireland were used to model Cryptosporidium oocyst transport using SWAT2005 on a daily basis with reference data from adjacent catchment gauging stations. The results indicated that SWAT2005 could simulate stream flow with good agreement between prediction and observation on a monthly basis (R(2) from 0.94 to 0.83 and E (efficiency) from 0.92 to 0.66), but Cryptosporidium oocyst concentration results were less reliable (R(2) from 0.20 to 0.37, P < 0.05; with poor E -0.37 to -2.57). A sensitivity analysis using independent parameter perturbation indicated that temperature was the most important parameter regulating oocyst transport in the study catchments and that the timing of manure application relative to the occurrence of water runoff event was critical. The results also showed that grazing management had little influence on predicted oocyst transport while fields fertilized with manure were the key critical source areas for microbial contaminations in the study catchments. It was concluded that the approach presented could be used to assist with understanding the epidemiology of waterborne cryptosporidiosis outbreaks and to improve catchment management for the safety of the general public health.

Cryptosporidium spp. and Giardia duodenalis in two areas of Galicia (NW Spain)

The aim of the present study was to investigate the environmental dispersal of Cryptosporidium spp. and Giardia duodenalis in two distinct areas (coastal and inland) in Galicia (NW Spain). Faecal samples were collected from healthy asymptomatic domestic (cows and sheep) and wild animals (deer and wild boars) in the selected areas. In each of the selected areas, samples of untreated water (influent) and of treated water (final effluent) were collected from each of the 12 drinking water treatments plants (DWTPs) and 12 wastewater treatment plants (WTPs) under study. Analysis of a single sample from each of the 635 (coastal) and 851 (inland) domestic and wild animals selected at random revealed that the prevalences of cryptosporidiosis and giardiosis in coastal area were 9.2% and 15.9% respectively, and in inland area, 13.7% and 26.7% respectively. In the coastal area, Cryptosporidium spp. oocysts were detected in influent and effluent samples from 2/12 (16.6%) DWTPs and 8/12 (66.6%) WTPs, while G. duodenalis cysts were detected in influent and effluent samples from 3/12 (25.0%) DWTPs and 12/12 (100%) WTPs. The concentrations were notably higher in WTPs; the mean parasite concentrations in the final treated effluent were 10 oocysts per litre and 137.8 cysts per litre for Cryptosporidium and Giardia, respectively. The mean concentration of G. duodenalis cysts per litre was significantly higher (P<0.05) than the mean concentration of Cryptosporidium spp. oocysts per litre in both the influent and the effluent samples from all the treatment plants. In the coastal area, C. parvum, C. hominis and G. duodenalis assemblages A (I and II) and E were most repeatedly detected. In the inland area, C. parvum, C. andersoni and G. duodenalis assemblages A (I and II), B and E were most frequently identified.

Molecular characterization of Cryptosporidium spp. in pre-weaned dairy calves in the Czech Republic: absence of C. ryanae and management-associated distribution of C. andersoni, C. bovis and C. parvum subtypes

A total of 750 faecal samples of dairy calves at up to 2 months of age kept in various housing systems were screened for Cryptosporidium spp. infection using the aniline-carbol-methyl violet staining method. DNA was extracted from Cryptosporidium positive samples and from 150 randomly selected microscopically negative samples. Nested PCR was performed to amplify the partial SSU rRNA gene of Cryptosporidium that was subsequently digested by SspI, VspI and MboII restriction enzymes to determine the present Cryptosporidium species and genotype. In addition, the samples characterized as Cryptosporidium parvum were subsequently analyzed at the GP60 gene to determine the distribution of zoonotic subtypes. Sequence analyses and RFLP identified C. parvum in 137, Cryptosporidium andersoni in 21 and Cryptosporidium bovis in 3 samples. Neither mixed infections nor Cryptosporidium ryanae was detected. Sequencing of the GP60 gene from C. parvum-positive samples revealed all five subtypes of family IIa (A15G2R1, A16G1R1, A22G1R1, A18G1R1, and A15G1R1). The obvious management-associated distribution of Cryptosporidium spp. was demonstrated. Direct contact with adult animals was found to be a risky factor for C. andersoni and C. bovis infection. IIaA15G2R1 and IIaA16G1R1 were detected as major subtypes, whereas only the IIaA16G1R1 subtype was found in animals kept in boxes. Three of the five detected subtypes were previously associated with human cryptosporidiosis, and moreover, the IIaA15G1R1 subtype, previously reported in humans only, was detected in calves for the first time.

The potential for zoonotic transmission of Giardia duodenalis and Cryptosporidium spp. from beef and dairy cattle in Ontario, Canada

The objective of this study was to compare the occurrence and the genotypes and species of Giardia duodenalis and Cryptosporidium spp. in beef and dairy cattle from farms in the Regional Municipality of Waterloo, Ontario, in an effort to determine the potential for zoonotic transmission from these animals. Pooled manure samples were collected from 45 dairy cattle farms and 30 beef cattle farms. The presence of Giardia cysts and Cryptosporidium oocysts was determined by immunofluorescence microscopy, while nested-PCR and DNA sequencing were used to determine genotypes and species. The overall farm prevalence was very high for both Giardia and Cryptosporidium, and was similar for dairy cattle farms (96 and 64%, respectively) and beef cattle farms (97 and 63%, respectively). However, on dairy cattle farms, G. duodenalis and Cryptosporidium spp. were detected in 44% and 6% of total pooled pen manure samples, respectively, with the occurrence of both parasites being generally higher in calves than in older animals. Most Giardia isolates were identified as either the host-adapted genotype G. duodenalis Assemblage E or the zoonotic Assemblage B. Cryptosporidium parvum and Cryptosporidium andersoni were the most frequently identified species in dairy cattle, while the non-zoonotic species Cryptosporidium ryanae and Cryptosporidium bovis were also found. On beef cattle farms, 72% and 27% of the total pooled pen manure samples were positive for Giardia and Cryptosporidium, respectively, with no obvious correlation with age. All Giardia isolates in beef cattle were identified as G. duodenalis Assemblage E, while all Cryptosporidium isolates were identified by sequence analysis as C. andersoni, although microscopic analyses, and subsequent restriction fragment length polymorphism analyses, indicated that other Cryptosporidium species were also present. The results of this study indicate that although Giardia and Cryptosporidium were identified in a higher overall percentage of the pooled beef cattle manure samples than in dairy cattle, firmly established zoonotic genotypes and species were much more common in dairy cattle than in beef cattle in this region. Dairy cattle, and especially dairy calves, may, therefore, pose a greater risk of infection to humans than beef cattle. However, these results may also provide evidence of potential zooanthroponotic transmission (human to animal).

Estimated human health risks from exposure to recreational waters impacted by human and non-human sources of faecal contamination

This work was conducted to determine whether estimated risks following exposure to recreational waters impacted by gull, chicken, pig, or cattle faecal contamination are substantially different than those associated with waters impacted by human sources such as treated wastewater. Previously published Quantitative Microbial Risk Assessment (QMRA) methods were employed and extended to meet these objectives. Health outcomes used in the analyses were infection from reference waterborne pathogens via ingestion during recreation and subsequent gastrointestinal (GI) illness. Illness risks from these pathogens were calculated for exposure to faecally contaminated recreational water at the U.S. regulatory limits of 35 cfu 100 mL(-1) enterococci and 126 cfu 100 mL(-1)Escherichia coli. The probabilities of GI illness were calculated using pathogen dose-response relationships from the literature and Monte Carlo simulations. Three scenarios were simulated, representing a range of feasible interpretations of the available data. The primary findings are that: 1) GI illness risks associated with exposure to recreational waters impacted by fresh cattle faeces may not be substantially different from waters impacted by human sources; and 2) the risks associated with exposure to recreational waters impacted by fresh gull, chicken, or pig faeces appear substantially lower than waters impacted by human sources. These results suggest that careful consideration may be needed in the future for the management of recreational waters not impacted by human sources.

Cryptosporidium ubiquitum n. sp. in animals and humans

A new species, Cryptosporidium ubiquitum, previously identified as the Cryptosporidium cervine genotype and infrequently as the cervid, W4 or genotype 3 genotype, is described. In published studies this genotype was reported in wild and domesticated ruminants, rodents, carnivores and primates including humans. In the present study oocysts were found in feces from a captive prehensile-tailed porcupine and her infant. Oocysts from the porcupine were transmitted to 4 boer goats. Oocysts from the goats were transmitted to a calf (calf 1) and oocysts from calf 1 were transmitted to gerbils and BALB/c mouse pups. Calf 2 housed near calf 1 became contaminated and excreted oocysts of C. ubiquitum. Oocysts collected from calf 2 were transmitted to a calf 3. When calf 2 stopped excreting C. ubiquitum oocysts it was challenged with oocysts of C. parvum and became infected, indicating a lack of cross-species immunity. Oocysts of C. ubiquitum from calf 1 measured 4.71-5.32 microm x 4.33-4.98 microm (mean=5.04 microm x4.66 microm) with a length/width shape index of 1.08 (n=50). Purified PCR products of the SSU rRNA, actin and COWP genes were sequenced and analysis of the 3 unlinked loci demonstrated the new species to be distinct from all other species and also demonstrated a lack of recombination, providing further evidence of species status. Based on morphological, molecular and biological data, this geographically widespread parasite infectious for a wide range of mammalian hosts is recognized as a new species and is named C. ubiquitum.

Species of Cryptosporidium detected in weaned cattle on cow-calf operations in the United States

To determine the species and distribution of Cryptosporidium in weaned beef calves in the United States, fecal specimens were collected from 819 cattle between 6 and 18 months of age from 49 operations in 20 states (Alabama, California, Colorado, Georgia, Idaho, Iowa, Kansas, Louisiana, Mississippi, Missouri, Nebraska, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Tennessee, Texas, Virginia, and Wyoming). Fresh feces, collected either from the ground or directly from the rectum of each animal, were sieved and subjected to density gradient centrifugation to remove fecal debris and to concentrate oocysts. DNA extracted from each specimen was subjected to the polymerase chain reaction (PCR) using primers for the SSU rRNA gene. All PCR positive specimens were subjected to sequence analysis. Cryptosporidium was detected in 20.5% of the fecal samples. Cryptosporidium ryanae, C. bovis and C. andersoni were detected in 1.8, 4.8, and 14.0% of the 819 samples, respectively. California (number operations [n]=2), Iowa (n=3), and Nebraska (n=7) had the highest prevalence of infected weaned cattle with 44.4, 41.0 and 40.2% infected, respectively. Cryptosporidium was not detected in any weaned cattle from Alabama (number operations [n]=1), Georgia (n=2), New Mexico (n=1), South Dakota (n=1), Tennessee (n=1), or Texas (n=1). The zoonotic species, C. parvum, was not detected in any samples from 6- to 18-month-old cattle, a finding that parallels reports for dairy cattle of similar age in which less than 1% were found to harbor this species.

Spinacia oleracea L. leaf stomata harboring Cryptosporidium parvum oocysts: a potential threat to food safety

Cryptosporidium parvum is a cosmopolitan microscopic protozoan parasite that causes severe diarrheal disease (cryptosporidiosis) in mammals, including humans and livestock. There is growing evidence of Cryptosporidium persistence in fresh produce that may result in food-borne infection, including sporadic cases as well as outbreaks. However, drinking and recreational waters are still considered the major sources of Cryptosporidium infection in humans, which has resulted in prioritization of studies of parasite etiology in aquatic environments, while the mechanisms of transmission and parasite persistence on edible plants remain poorly understood. Using laser scanning confocal microscopy together with fluorescein-labeled monoclonal antibodies, C. parvum oocysts were found to strongly adhere to spinach plants after contact with contaminated water, to infiltrate through the stomatal openings in spinach leaves, and to persist at the mesophyll level. These findings and the fact that this pathogenic parasite resists washing and disinfection raise concerns regarding food safety.

Giardia duodenalis in feedlot cattle from the central and western United States

BACKGROUND

Giardia duodenalis is a ubiquitous protozoan parasite that has emerged as a significant opportunistic human pathogen. G. duodenalis may have a deleterious effect on animal growth and performance, therefore its potential as a production limiting organism should not be discounted. We therefore undertook this study to determine management and environmental factors in feedlots that influence the prevalence and environmental load of G. duodenalis cysts in fecal material deposited by feedlot cattle in the central and western United States.

RESULTS

Twenty two feedlots from 7 states were included in the study, and up to 240 fecal samples were collected from pen floors of up to 6 pens per feedlot. Giardia duodenalis cysts were identified and counted using direct immunofluorescent microscopy. The estimated overall point prevalence of G. duodenalis was 19.1%, representing feedlots from a wide range of climates and management systems. Pen-level prevalence varied from 0 to 63.3%, with pen-level shedding estimates ranging from 0 to 261,000 cysts/g feces. Higher environmental temperatures, increased animal density, and increased time in the feedlot were associated with a lower prevalence of G. duodenalis. Removing manure before placing a new group of cattle in a pen was associated with a decreased prevalence of G. duodenalis in fecal pats. Using coccidiostats as a feed additive was associated with a higher prevalence of Giardia.

CONCLUSION

Management practices could be employed that would limit the probability that feedlot cattle shed G. duodenalis in their feces and therefore potentially limit contamination of their environment.

Detection of Cryptosporidium spp. and Giardia duodenalis in surface water: a health risk for humans and animals

The objective of the present study was to determine the degree of contamination by Cryptosporidium spp. and Giardia duodenalis in a river basin in a livestock farming area in Galicia (NW, Spain). Water samples (50 l) were collected at 22 points in the main basin (including 5 recreational areas), and at the source and mouth of the 3 most important rivers and at the mouth of a smaller, secondary river. Faecal samples were collected from dairy cattle selected at random from 18 herds farmed in the area. A total of 139 neonatal calves, 480 heifers and 697 cows were sampled. The prevalence, intensity of infection and the risk associated with the spread of infection by both enteropathogens were determined. Water and faecal samples were collected in spring, summer, autumn and winter of 2007. The species and genotypes of these parasites present in the water samples were identified. In both water and faecal samples, more parasitic stages were collected in spring and summer than in autumn and winter. In spring, Cryptosporidium spp. oocysts were detected in 33 (9.4%) cows from 13 (72.2%) herds, and G. duodenalis cysts were detected in 56 (16.0%) cows from 15 farms (83.3%); the intensity of infection ranged from 5 to 7895 G. duodenalis cysts per gram of faeces. Infective stages of Cryptosporidium spp. and G. duodenalis were also detected in respectively 26 (89.6%) and 27 (93.1%) water samples, in spring. The mean concentrations of parasites ranged from 2 to 1200 Cryptosporidium spp. oocysts per litre and from 2 to 400 G. duodenalis cysts per litre. Cryptosporidium parvum, C. andersoni, C. hominis and assemblages A-I, A-II, E of G. duodenalis were detected. The presence of both protozoans must be monitored in cattle, in sources of water used for recreational purposes and in artificial waterways used by farmers (water channels, animal drinking water and drainage systems).

A multiplex polymerase chain reaction assay to simultaneously distinguish Cryptosporidium species of veterinary and public health concern in cattle

Four species of Cryptosporidium are routinely found in cattle: Cryptosporidium parvum, Cryptosporidium bovis, Cryptosporidium ryanae, and Cryptosporidium andersoni. It is important to determine the species of Cryptosporidium in infected cattle because C. parvum is the only serious pathogen for humans as well as cattle. Identification of Cryptosporidium species and genotypes currently relies on molecular methods such as polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) or gene sequencing. Incorporation of these techniques in a routine veterinary diagnostic laboratory is cost prohibitive. As such, their applications are limited primarily to research and a few public health laboratories. To overcome this problem, a multiplex PCR assay was developed for simultaneously detecting the 4 species of Cryptosporidium that commonly infect cattle. This assay specifically identifies Cryptosporidium oocysts present in cattle feces, improves the detection of mixed infections, reduces the time and cost relative to current sequencing methods, and further demonstrates the shortcomings of sequencing as the definitive method for identification when analyzing samples containing mixed infections.

Cryptosporidium xiaoi n. sp. (Apicomplexa: Cryptosporidiidae) in sheep (Ovis aries)

A new species, Cryptosporidium xiaoi, is described from sheep. Oocysts of C. xiaoi, previously identified as the Cryptosporidium bovis-like genotype or as C. bovis from sheep in Spain, Tunisia, United Kingdom, and the United States are recorded as such in GenBank (EU408314-EU408317, EU327318-EU327320, EF362478, EF514234, DQ991389, and EF158461). Oocysts obtained from naturally infected sheep were infectious for a lamb and oocysts from that lamb were infectious for three other lambs. The prepatent period for C. xiaoi in these four Cryptosporidium-naive lambs was 7-8 days and the patent period was 13-15 days. Oocysts are similar to those of C. bovis but slightly smaller, measuring 2.94-4.41 microm x 2.94-4.41 microm (mean=3.94 microm x 3.44 microm) with a length/width shape index of 1.15 (n=25). Oocysts of C. xioai were not infectious for BALB/c mice, Bos taurus calves, or Capra aegagrus hircus kids. Fragments of the SSU-rDNA, HSP-70, and actin genes were amplified by PCR, purified, and PCR products were sequenced. The new species was distinct from all other Cryptosporidium species as demonstrated by multi-locus analysis of the 3 unlinked loci. Based on morphological, molecular and biological data, this geographically widespread parasite found in Ovis aries is recognized as a new species and is named C. xiaoi.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy calves from 11 farms in Prince Edward Island, Canada

Cryptosporidium spp. are common intestinal protozoan parasites that infect a wide range of hosts, including humans and livestock, worldwide. The objective of this study was to determine the prevalence of Cryptosporidium spp. in dairy calves in Prince Edward Island, Canada, and the potential for transmission of this parasite between dairy calves and humans. Fecal samples were collected from 183 dairy calves from 11 farms in Prince Edward Island. The prevalence of Cryptosporidium spp. infections in these animals was determined by examining for the presence of oocysts in the fecal samples, using immunofluorescence microscopy. Molecular characterization was done using a nested-PCR protocol to amplify fragments of the Cryptosporidium heat-shock protein 70 gene, followed by DNA sequencing. Ten calves (6.2%), representing 4 out of 11 farms tested, were positive for Cryptosporidium spp. DNA sequence analysis on five PCR positive samples demonstrated that Cryptosporidium parvum was the only species present in the calves tested, suggesting that there is a potential risk of zoonotic transmission between dairy calves and humans in this region.

Synanthropic flies as vectors of Cryptosporidium and Giardia among livestock and wildlife in a multispecies agricultural complex

The capacity of synanthropic flies belonging to the families Calliphoridae, Sarcophagidae, and Muscidae to serve as mechanical vectors of Cryptosporidium and Giardia among livestock and wildlife in a multispecies agricultural complex in northwest Georgia (USA) was studied using fluorescent in situ hybridization (FISH) and immunofluorescent antibody (IFA) techniques. Flies from all three families were carrying viable Cryptosporidium oocysts and Giardia cysts internally and externally, and deposited them on trap surfaces. Furthermore, the contaminated flies and trap surfaces occurred in association with each of the four domestic animal units (beef, dairy, equine, and sheep), and in wildlife areas dominated by deer (Odocoileus virginianus) and Canada Geese (Branta canadensis). Cryptosporidium was isolated from 55.56% of the fly samples, whereas Giardia was isolated from only 7.94%. The highest numbers of Cryptosporidium were associated with cattle and wildlife areas, while Giardia occurred in greatest numbers in the sheep area. Cryptosporidium was isolated comparably from exoskeletal elutants and fly homogenates, but Giardia was isolated primarily from homogenates, indicating primarily internal transport in the latter. Surfaces visited by the flies (i.e., traps) became contaminated by both Cryptosporidium (18.89%) and Giardia (1.11%). In conclusion, these flies can serve as mechanical vectors of both Cryptosporidium and Giardia in all of these settings, and undoubtedly play a role in movement of these pathogens among the various host species.

A survey of enteric bacteria and protozoans in fresh bovine faeces on New Zealand dairy farms

AIMS

To determine the counts and/or prevalence in fresh bovine faeces of Escherichia coli, enterococci, Campylobacter, Salmonella, shiga toxin-producing E. coli (STEC), Giardia and Cryptosporidium, as inputs to numerical models designed to estimate microbial loadings on pasture grazed by cattle in New Zealand.

METHODS AND RESULTS

In each season over one year, samples of freshly deposited bovine faeces were collected from four New Zealand dairy farms (n = 155), and enumerated for E. coli, enterococci, Campylobacter, Giardia and Cryptosporidium. They were also tested for the presence of Salmonella and STEC. The overall median bacterial counts (g(-1) wet weight) were E. coli- 5.9 x 10(6); enterococci - 1.3 x 10(4); Campylobacter- 3.9 x 10(5). All counts were highly variable within and between samplings, and few seasonal or regional patterns emerged. However, mean Campylobacter counts were consistently higher in spring. No Salmonella spp. was detected, and only two samples were positive for STEC. Cryptosporidium and Giardia were isolated from 5.2% and 4.5% of the samples, respectively, yielding low numbers of (oo)cysts (1-25 g(-1) and 1-17 g(-1), respectively).

CONCLUSIONS

Fresh bovine faeces are a significant source of E. coli, enterococci and Campylobacter on New Zealand pastures, although numbers are likely to vary markedly between faecal samples.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study provides the first significant set of indicator and pathogen counts for one of the largest sources of faecal contamination of natural waters in New Zealand, and will be used to model these inputs.

Cryptosporidium ryanae n. sp. (Apicomplexa: Cryptosporidiidae) in cattle (Bos taurus)

A new species, Cryptosporidium ryanae, is described from cattle. Oocysts of C. ryanae, previously identified as the Cryptosporidium deer-like genotype and recorded as such in GenBank (AY587166, EU203216, DQ182597, AY741309, and DQ871345), are similar to those of Cryptosporidium parvum and Cryptosporidium bovis but smaller. This genotype has been reported to be prevalent in cattle worldwide. Oocysts obtained from a calf for the present study are the smallest Cryptosporidium oocysts reported in mammals, measuring 2.94-4.41micromx2.94-3.68microm (mean=3.16micromx3.73microm) with a length/width shape index of 1.18 (n=40). The pre-patent period for two Cryptosporidium-naïve calves fed C. ryanae oocysts was 11 days and the patent period was 15-17 days. Oocysts were not infectious for BALB/c mice or lambs. Fragments of the SSU-rDNA, HSP-70, and actin genes amplified by PCR were purified and PCR products were sequenced. Multi-locus analysis of the three unlinked loci demonstrated the new species to be distinct from all other species and also demonstrated a lack of recombination, providing further evidence of species status. Based on morphological, molecular and biological data, this geographically widespread parasite found only in Bos taurus calves is recognized as a new species and is named C. ryanae.

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.

Evaluation of two DNA template preparation methods for post-immunomagnetic separation detection of Cryptosporidium parvum in foods and beverages by PCR

Cryptosporidium parvum oocysts were recovered by immunomagnetic separation from six artificially contaminated foods. Two DNA isolation methods were subsequently evaluated by PCR. The FTA Concentrator-PS filter provided rapid and reproducible detection, although variability increased at lower inoculum levels (88% and 15% detection in high- and low-inoculum-level samples, respectively). Total DNA extraction generated consistent results at all oocyst levels but resulted in longer analysis time (100% and 59% detection in high- and low-inoculum-level samples, respectively). Also reflected in this study was that the matrix played an important role in the ability to recover oocysts, as sample turbidity, pH, and PCR inhibitors all influenced detection.

Occurrence of Cryptosporidium parvum and Giardia duodenalis in healthy adult domestic ruminants

To determine the prevalence and intensity of infection of Cryptosporidium spp. and Giardia duodenalis in healthy adult domestic ruminants, faecal samples were collected from 379 cattle of between 3 and 13 years old, 446 sheep and 116 goats selected at random from 60 dairy farms and 38 and 20 herds, respectively, in Galicia (NW Spain). Cryptosporidium spp. oocysts were detected in 32 cows (8.4%), 24 sheep (5.3%) and in nine goats (7.7%) from, respectively, 48.3% of the farms and 34.2 and 30.0% of the herds. The intensity of infection in cows ranged between 25 and 5,924 oocysts per gram of faeces (OPG), whereas in sheep and goats, the number of oocysts shed ranged from 8-515 OPG and from 17-782 OPG, respectively. Parasitization by Cryptosporidium spp. was significantly higher (P<0.05) in cows than in sheep and goats. G. duodenalis cysts were identified in 101 cows (26.6%), 86 sheep (19.2%) and 23 goats (19.8%) from, respectively, 96.6% of the farms and 92.1 and 90% of the herds. The number of cysts shed by cows ranged between 15 and 3,042 cyst per gram of faeces (CPG), whereas the intensity of infection in sheep and goats ranged from 16-3010 CPG and from 15-1845 CPG, respectively, and was significantly lower (P<0.05) than in cows and sheep. The number of Cryptosporidium spp. oocysts isolated from sheep and goats was insufficient for successful polymerase chain reaction analysis. Nevertheless, gene sequence analysis of the hsp70 and 18SrRNA genes of Cryptosporidium revealed the presence of only C. parvum in faecal samples from cows. Genotyping studies of the beta-giardin and glutamate dehydrogenase genes of G. duodenalis revealed mainly assemblage E of Giardia in cows, sheep and goat faecal samples. Assemblage B of G. duodenalis was also detected in one sheep sample. These animals should be considered as a possible source of cryptosporidiosis and giardiosis, thereby maintaining the infections on farms and in herds.

INTRAGENOTYPIC VARIATIONS IN THE CRYPTOSPORIDIUM SP. CERVINE GENOTYPE FROM SHEEP WITH IMPLICATIONS FOR PUBLIC HEALTH

Cryptosporidium sp. cervine genotype could possibly emerge as an important human pathogen because current evidence suggests this genotype has a wide host range and zoonotic potential. However, there is confusion in the taxonomy of the Cryptosporidium sp. cervine genotype because different names have been used to refer to this genotype in previous studies and in sequences submitted to GenBank. Consequently, we lack a clear understanding of the epidemiology of this genotype. In the present study, the Cryptosporidium sp. cervine genotype was identified in sheep, was characterized using 3 genes (18S rDNA, COWP, and HSP-70), and was compared with data from all previous reports. Intragenotypic variations were found at the 18S rDNA gene in Cryptosporidium sp. cervine genotype with 3 different subtypes (cervine 1-3). No sequence variation at HSP-70 and COWP genes were observed. Sheep should be considered as an important reservoir for this zoonotic genotype of Cryptosporidium sp.

Phylogenetic analysis implicates birds as a source of Cryptosporidium spp. oocysts in agricultural watersheds

Cryptosporidium parvum and C. hominis are protozoan parasites responsible for cryptosporidiosis, an acute gastrointestinal illness that can be life-threatening for immunocompromised persons. Sources and genotypes of Cryptosporidium oocysts were investigated in two agricultural areas within the Wachusett Reservoir watershed, a drinking water source for Boston, Massachusetts. Two brooks (denoted Brook SF and Brook JF, respectively), each downgradient from a dairy farm, were chosen as sample sites. For one year, Brooks SF and JF were sampled monthly; oocysts were detected in 6 (50%) out of 12 samples from Brook JF, and no oocysts were detected in Brook SF. Oocyst genotypes from agricultural surface waters were compared to oocyst genotypes from Genbank, as well as fecal samples of cattle and birds, using phylogenetic analysis of a hypervariable region of the 18S rRNA gene by both neighbor-joining and parsimony methods. Results show extensive heterogeneity among Cryptosporidium spp. 18S rRNA sequences, and also suggest that birds are an oocyst source in this watershed. Principal components analysis showed oocyst presence correlating strongly with seasonal factors, and oocysts in surface waters were only detected in the summer through late fall, co-incident with the presence of migratory birds in this watershed. If birds are confirmed to be an important source of oocysts infectious to humans, the data suggest that protection of raw drinking water supplies in some agricultural areas may depend upon management and control of resident and migratory bird populations.

Prevalence and molecular characterization of Cryptosporidium and Giardia species and genotypes in sheep in Maryland

In the United Kingdom and Australia sheep have been implicated as sources of Cryptosporidium and Giardia that infect humans, but no such studies have been conducted in North America. Therefore, a study was undertaken to investigate the prevalence of these parasites in sheep on a farm in Maryland. Feces were collected from 32 pregnant ewes 1, 2, and 3 days after parturition and from each of their lambs 7, 14, and 21 days after birth. The presence of Cryptosporidium oocysts and Giardia cysts was determined by both immunofluorescence microscopy and PCR/gene sequence analysis. PCR was consistently more sensitive than microscopy. The prevalence, by PCR, of Cryptosporidium in ewes and lambs was 25 and 77.4%, respectively. Three species/genotypes of Cryptosporidium were identified: C. parvum, a novel C. bovis-like genotype, and Cryptosporidium cervine genotype. Cryptosporidium parvum and the cervine genotype have been reported worldwide in human infections. The novel C. bovis-like genotype is reported here for the first time. The prevalence of Giardia in ewes and lambs was 12 and 4%, respectively. Most infections were Assemblage E which is not zoonotic; however, one ewe was infected with zoonotic Assemblage A. The identification of only two lambs infected with C. parvum and one ewe infected with G. duodenalis Assemblage A suggests a low prevalence of these zoonoses. However, the high prevalence of the zoonotic cervine genotype indicates that sheep should be considered a potential environmental source of this human pathogen.

Cryptosporidium, Giardia and Enterocytozoon bieneusi in cats from Bogota (Colombia) and genotyping of isolates

The prevalence of Cryptosporidium, Giardia, and Enterocytozoon bieneusi in cats from Bogota (Colombia) was determined from fecal specimens and scrapings of duodenal and ileal mucosa screened by PCR. All PCR-positive specimens were sequenced to determine the genotype(s) present. Of 46 cats, 6 (13%) were positive for Cryptosporidium, 5 (11%) were infected with C. felis and one (2%) with C. muris. Three (6.5%) cats were infected with Giardia duodenalis Assemblage F. Eight (17%) cats were infected with four genotypes of E. bieneusi: genotype D-like (9%), K (4%), Peru 10 (2%), and Peru 5 (2%). This is the first report on the presence of zoonotic species/genotypes of Cryptosporidium and E. bieneusi in cats in Colombia.

Prevalence and Intensity of Infection of Cryptosporidium spp. and Giardia duodenalis in Dairy Cattle in Galicia (NW Spain)

Faecal samples were collected from 734 cattle selected at random from 60 dairy farms in Galicia (NW Spain). The animals studied were classified into 12 age groups: <1 month (53); 1-5 months (30); 6-11 months (31); 12-16 months (72); 17-20 months (64); 21-24 months (96); 3 years (94); 4 years (74); 5 years (67); 6 years (67); 7-8 years (63) and 9-13 years (23). Oocysts of Cryptosporidium spp. were identified in 104 animals (14.2%) distributed throughout all of the age groups and from 40 different farms (66.7%). The percentage of cattle infected ranged between 58.5% in calves <1 month and 7.9% in 7 to 8-year-old cows, i.e. the percentage of infection decreased significantly (P < 0.05) with increasing age. The intensity of infection in animals older than 1 month ranged between 10 and 5924 oocysts/g of faeces and there were no significant differences between the different groups. Cysts of Giardia duodenalis were identified in 221 animals (30.1%) from 56 farms (93.3%). The parasite was detected in all age groups, at rates of infection ranging between 21.8% (9-13 years) and 56.7% (1-5 months), although these differences were not statistically significant. The intensity of infection ranged between 7 and 15 412 cysts/g of faeces, with the number of cysts shed being significantly higher (P < 0.05) in calves <1 month than in calves aged 1-5 months. Significant associations between parasitisation by Cryptosporidium spp. or G. duodenalis and the consistency of the faeces were only found in calves aged <1 month and 1-5 months. Concurrent infections were more prevalent in the groups of calves of 1-5 months (23.3%) and 6-11 months (25.8%).