Cryptosporidium parvum infection in cattle: are current perceptions accurate?

Frequency and Molecular Identification of Cryptosporidium in Adult Prim'Holstein Dairy Cattle Farms in the North of France

Cryptosporidium apicomplexan protozoa are ubiquitous intracellular agents affecting humans and animals. In particular, bovine cryptosporidiosis is recognized as endemic worldwide. However, epidemiological investigations remain limited in France regarding the burden of these parasites in cattle. To improve our understanding of the epidemiology of cryptosporidiosis, the main aim of this study was to determine the frequency and the genetic diversity of Cryptosporidium in adult Prim'Holstein dairy cattle farms in the north of France. Fecal specimens were collected from 1454 non-diarrheic and non-pregnant animals (nulli-, primi-, or multiparous) throughout 20 farms in an area of 110 km around Lille. For Cryptosporidium species identification, nested PCR followed by sequence and phylogenetic analyses were used. The overall frequency of Cryptosporidium spp. in-fection was 30.00% (C.I. 95%: 12.83-54.33) in farms and 0.89% (C.I. 95%: 0.498-1.57) at the individual level. In primi- or multiparous cows, only C. andersoni was found. C. ryanae, C. bovis/xiaoi and C. andersoni were detected in heifers. The phylogenetic tree confirmed that analyzed sequences were grouped with known reference sequences reported in dairy cattle. Further studies on the cumulative prevalence, risks factors and pathogenicity are needed to give a more accurate assessment of the impact of Cryptosporidium infection in dairy cattle in France.

Genetic characterisation of Cryptosporidium parvum in dairy cattle and calves during the early stages of a calving season

Cryptosporidium parvum is a causative agent of cryptosporidiosis, an infectious gastroenteritis in neonatal ruminants, which can be fatal in severe cases. The aim of this study was to determine the prevalence of infections in dairy cattle/calves during the early stages of a calving season and the species/genotypes of the Cryptosporidium present. Faecal samples collected from pre- and post-partum dams (n = 224) as well as calves from age ∼1 day onwards (n = 312) were examined. Oocysts were concentrated, DNA extracted and tested by Cryptosporidium 18S rRNA gene PCR and sequencing, while genotypes of C. parvum were determined by gp60 and VNTR analysis. Results showed that 31.3% and 30.4% of pre- and post-partum dams tested positive for Cryptosporidium, respectively. In the adults, C. parvum (n = 52), C. bovis (n = 4) and C. andersoni (n = 19) were identified, while in the calves 248 out of 312 (79.5%) were PCR-positive for C. parvum. The proportion of positive calf samples was significantly higher (P < 0.0001) than the proportion of positive adult cattle during the first seven weeks of the calving season. In adult cattle, three distinct gp60 genotypes were identified, a predominant genotype IIaA15G2R1 (n = 36) and genotypes IIaA15R1 (n = 2) and IIaA14G2R1 (n = 1). In the calves, only genotype IIaA15G2R1 was detected (n = 125). Although C. parvum was observed in adult cattle two weeks after the start of the calving season, the predominant genotypes were not detected until Week 4 in both adults and calves, meaning it is still unclear whether adult cattle are the initial source of C. parvum infections on the farm. Historically calves on this dairy farm demonstrated the IIaA19G2R1 genotype, which, has now clearly been replaced with the IIaA15G2R1 genotype that is now found in both adults and calves. During the study season, significantly higher levels of neonatal calf mortality were observed compared to the seasons before (P = 0.046) and after (P = 0.0002). This study has shown comparable levels of C. parvum infection in both pre- and post-partum dams but higher levels of infection in neonatal calves.

Eukaryotic Infections in Dairy Calves: Impacts, Diagnosis, and Strategies for Prevention and Control

Eukaryotic infections are common among dairy calves and can have significant impacts on their health and growth rates. Fungal infections caused by Aspergillus fumigatus, Trichophyton verrucosum, and Candida albicans can cause respiratory diseases, dermatophytosis, and diarrhea, respectively. Protozoan parasites, including Cryptosporidium parvum, Giardia duodenalis, and Eimeria spp., are also common in dairy calves. C. parvum is highly contagious and can cause severe diarrhea and dehydration, while Giardia duodenalis can lead to poor growth and is transmissible to humans through contaminated food or water. Eimeria spp. can cause coccidiosis and lead to reduced growth rates, poor feed conversion, and death. The common helminthic infections in dairy calves include Ostertagia ostertagi, Cooperia spp., Fasciola hepatica, and Strongyloides papillosus. These parasitic infections significantly impact calf health, growth, and dairy industry productivity. Diagnosis of these infections can be made through fecal samples using microscopy or molecular methods. However, diagnosis of the infections can be challenging and requires a combination of clinical signs and laboratory tests such as culture and PCR. Preventing and controlling eukaryotic infections in dairy calves requires several measures. Good hygiene and sanitation practices, proper management strategies, and timely treatment of affected animals are important. It is also necessary to avoid overcrowding and consider vaccination against ringworm. Further research is needed to better understand the epidemiology and characterization of eukaryotic infections in dairy calves, which will help in the development of more effective prevention and control strategies. In general, good hygiene practices, appropriate management strategies, and timely treatment of affected animals are crucial in preventing and controlling the infections, ensuring the health and well-being of dairy calves.

Cryptosporidium parvum and gp60 genotype prevalence in dairy calves worldwide: a systematic review and meta-analysis

Cryptosporidium is a significant zoonotic pathogen that often occurs in dairy cattle. We conducted a systematic review and meta-analysis of the prevalence of Cryptosporidium parvum infection in dairy calves worldwide to help improve global animal husbandry and public policy implementation. Published articles were obtained from PubMed and Web of Science from January 1, 2000 to December 31, 2021. The prevalence of C. parvum infection in dairy calves was estimated using a random effects model, and the sources of heterogeneity were explored using meta-regression. In total, 118 datasets were included in the final quantitative analysis. The results showed that the global prevalence of C. parvum in dairy calves was 21.9% (7755/42,890; 95% confidence interval: 19.9-23.9%). C. parvum infection was high in pre-weaned dairy calves (24.9%, 6706/29,753) and diarrhea dairy calves (33.6%, 1637/6077). In countries with low dairy stocking density (<10 cows/farm), the prevalence of C. parvum in dairy calves was also relatively low (15.2%, 1960/16,584). Three subtype families [IIa (72.2%, 2293/3177), IId (27.4%, 872/3177), and IIl (0.4%, 12/3177)] were detected in dairy calves globally from selected studies. C. parvum IIa was the dominant zoonotic subtype. In the IIa subtype family of C. parvum, the proportions of subtypes from high to low (top nine) were IIaA15G2R1 (32.4%, 742/2293), IIaA18G3R1 (11.8%, 271/2293), IIaA13G2R1 (8.2%, 187/2293), IIaA16G1R1 (6.4%, 147/2293), IIaA20G1R1 (3.5%, 81/2293), IIaA16G3R1 (3.4%, 78/2293), IIaA17G2R1 (2.7%, 62/2293), IIaA18G1R1 (2.5%, 58/2293), and IIaA15G1R1 (2.4%, 56/2293). In the IId subtype family of C. parvum, the proportions of subtypes (top four) were IIdA19G1 (36.0%, 314/872), IIdA15G1 (27.3%, 238/872), IIdA20G1 (16.2%, 141/872), and IIdA14G1 (13.0%, 113/872). Furthermore, IId is commonly found in China (771/872). The study results indicated that the IIa subtype family is globally prevalent, while IId is found in Asia, Europe, and Africa and IIl is only found in Europe. Diarrhea in dairy calves is associated with C. parvum infection and a significantly higher prevalence is observed in diarrheic calves. Age and stock density are two significant risk factors in the prevalence of C. parvum in dairy calves. The prevention and control of this zoonosis in dairy calves should receive greater attention, especially in regions with a high degree of intensive dairy farming.

Rearing system with nurse cows and risk factors for Cryptosporidium infection in organic dairy calves

Rearing dairy calves with nurse cows has been increasingly adopted by French farmers especially in organic farming and is characterized by a fostering of two to four calves during the first month of life by an unmilked lactating cow. This type of rearing remains poorly documented regarding its impact on calf health, such as cryptosporidiosis. The objectives of our study were to describe practices related to rearing dairy calves with nurse cows and to evaluate the prevalence, intensity and risk factors for Cryptosporidium infection in calf neonates. Between January and September 2019, the rearing practices of calves were described in 20 organic French farms and faeces were sampled once from 611 animals aged between 5 and 21 days. Cryptosporidium oocyst shedding was identified by modified Ziehl-Neelsen technique and scored semi-quantitatively (score 0-4). The risk of excretion (score 0 versus 1-4) was analysed using multivariate logistic regression models. This cow-calf rearing system usually consisted of a first phase with the dam, followed by an optional phase of artificial milk feeding (calves being fed with whole milk of the farm) and a final phase of fostering by a nurse cow. Each nurse was suckled from one to five calves of close age with a fostering age of 8 days on average. The oocyst shedding prevalence was 40.2 % and similar to classically reared calves, but the intensity of shedding and the prevalence of diarrhoea appeared to be lower. The identified six risk factors for oocyst shedding were: born in the last two thirds of the birth order, born between January and July versus August and September, calf with its dam in the barn versus on pasture, having an artificial milk feeding phase versus being with the dam only, and contact between peer calves and notably the presence of an oocyst excretory calf fostered by the same nurse. These results emphasize the role of the environment for the direct and indirect contamination, particularly that related to the accumulation of oocysts from previous or peer calves facilitating the faecal-oral route of transmission. This highlights the crucial role of the premises used intensively during the winter and spring months with higher densities of calves in the barn compared to outdoor situations promoted by this rearing.

The red fox (Vulpes vulpes) as a potential natural reservoir of human cryptosporidiosis by Cryptosporidium hominis in Northwest Spain

Giardia duodenalis and Cryptosporidium spp. are ubiquitous intestinal protozoa that parasitize domestic and wild animals, as well as human beings. Due to their zoonotic potential, the objective of the present study was to determine the presence of these pathogens in the fox population (Vulpes vulpes) located in Northwest Spain. A total of 197 faecal samples from legally hunted foxes were collected in the autonomous region of Galicia. The presence of G. duodenalis and Cryptosporidium spp. was investigated by PCR-based methods amplifying the small subunit ribosomal RNA (ssu rRNA) gene of the parasites. Attempts to genotype obtained positive samples were subsequently conducted at the glutamate dehydrogenase (gdh) and β-giardin (bg) genes of G. duodenalis, and the 60 kDa glycoprotein (gp60) gene of Cryptosporidium. Giardia duodenalis and Cryptosporidium spp. were identified in 19 (9.6%) and 12 (6.1%) of the investigated samples, respectively. However, five Cryptosporidium species were detected at the ssu rRNA locus: C. hominis (33.4%, 4/12), C. canis (25.0%, 3/12), C. parvum (16.7%, 2/12), C. ubiquitum (8.3%, 1/12) and C. suis (8.3%, 1/12). An additional Cryptosporidium-positive sample was identified at the genus level only. Typing and subtyping of Giardia- and Cryptosporidium-positive samples were unsuccessful. The detection of C. hominis in wild foxes indicates the probable overlapping of sylvatic and domestic cycles of this parasite in rural settings. Besides, this finding raises the question of whether red foxes may act as natural reservoirs of C. hominis. The detection of C. parvum and C. suis is suggestive of active transmission events between farm and wild animals, opening up the possibility of transmission to human beings.

Prevalence of Cryptosporidium in dairy cattle in China during 2008-2018: A systematic review and meta-analysis

Cryptosporidium is the causative agent of cryptosporidiosis. Cryptosporidium not only has a worldwide distribution, but also can infect various hosts, including dairy cattle and humans. Although numerous researches on Cryptosporidium infection in cattle have been conducted, no nationwide study on the prevalence of Cryptosporidium infection in dairy cattle in mainland China was carried out. In this meta-analysis, five databases, including PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP, and Wanfang, were used to search for published papers regarding Cryptosporidium infection in dairy cattle in China from inception to February 25, 2019. Our study obtained 60 eligibility studies that reported Cryptosporidium infection in dairy cattle. We estimated the pooled Cryptosporidium prevalence to be 17.0% (3,901/33,313), with 16.9% (722/5,191) in Central China, 17.4% (959/6,162) in Eastern China, 29.8% (404/2,021) in Northeastern China, 15.7% (227/2,344) in Northern China, 15.8% (1,042/11,452) in Northwestern China, 9.5% (494/5,758) in Southern China, and 13.7% (53/385) in Southwestern China. The pooled prevalence of Cryptosporidium in before 2000 group (28.0%, 944/3,417) was significantly higher than in 2000-2010 group (11.1%, 384/3,643) and after 2010 group (13.7%, 2,134/22,411). Cattle with the age of ≤ 12 months (22.5%, 2,142/12,948) had a significantly higher prevalence than those of > 12 months (9.5%, 840/10,282). The pooled prevalence of Cryptosporidium in different seasons ranged from 8.2% (343/4,552) in Autumn to 19.5% (285/1,570) in Winter. Diarrhea cattle (38%, 133/477) had a higher Cryptosporidium prevalence than non-diarrhea cattle (13.0%, 367/2423). The pooled prevalence of Cryptosporidium in different provinces was various, with the highest (35.6%, 355/1,667) in Heilongjiang province, and the lowest (4.3%, 15/440) in Tianjin province. The univariate meta-regression analyses indicated that the collection year (P = 0.002) and age of cattle (P = 0.001) might be sources of heterogeneity. This systematic review suggests that China is a country where cryptosporidiosis frequently occurs in cattle. Due to the particular relationship between dairy cattle and feeder, further research is required to investigate the links between cattle ownership and Cryptosporidium infection.

Assessing the impact of environmental exposures and Cryptosporidium infection in cattle on human incidence of cryptosporidiosis in Southwestern Ontario, Canada

Cryptosporidium is a waterborne parasite that causes diarrheal disease in humans and in cattle. Risk factors for human illness include contact with surface water such as lakes and rivers, exposure to contaminated municipal drinking water, as well as zoonotic transmission from livestock and agriculture. The objectives of this study are twofold: 1) to describe the temporal distribution of cryptosporidiosis in Southwestern Ontario; and 2) to determine the distribution of human cryptosporidiosis, in relation to exposures such as cryptosporidium positive cattle farms, weather events, and hydrological factors. Seasonal trends in 214 bovine and 87 human cases were assessed using regression models that predicted monthly case counts in relation to observed monthly case counts. A case-crossover approach was used to evaluate acute associations between daily environmental exposures, such as weather, hydrology, the presence of Cryptosporidium positive cattle farms within the region, and the risk of human Cryptosporidium infection. Annual seasonality was found for both human cases and bovine cases with human cases peaking in mid-summer and bovine cases peaking in late winter to early spring. Bovine cases that occurred 21 days prior to human cases were associated with a three-fold increase in the odds of human case occurrence. At both 9 and 14 days prior to human case onset, the odds of a human case increased twofold per 10-degree Celsius increase in air temperature. These results provide a preliminary hypothesis for the zoonotic transmission of cryptosporidiosis from cattle to humans via the environment and suggest that the timing of environmental conditions in relation to case occurrence is biologically plausible.

A perspective on Cryptosporidium and Giardia, with an emphasis on bovines and recent epidemiological findings

Cryptosporidium and Giardia are two common aetiological agents of infectious enteritis in humans and animals worldwide. These parasitic protists are usually transmitted by the faecal-oral route, following the ingestion of infective stages (oocysts or cysts). An essential component of the control of these parasitic infections, from a public health perspective, is an understanding of the sources and routes of transmission in different geographical regions. Bovines are considered potential sources of infection for humans, because species and genotypes of Cryptosporidium and Giardia infecting humans have also been isolated from cattle in molecular parasitological studies. However, species and genotypes of Cryptosporidium and Giardia of bovids, and the extent of zoonotic transmission in different geographical regions in the world, are still relatively poorly understood. The purpose of this article is to (1) provide a brief background on Cryptosporidium and Giardia, (2) review some key aspects of the molecular epidemiology of cryptosporidiosis and giardiasis in animals, with an emphasis on bovines, (3) summarize research of Cryptosporidium and Giardia from cattle and water buffaloes in parts of Australasia and Sri Lanka, considering public health aspects and (4) provide a perspective on future avenues of study. Recent studies reinforce that bovines harbour Cryptosporidium and Giardia that likely pose a human health risk and highlight the need for future investigations of the biology, population genetics and transmission dynamics of Cryptosporidium and Giardia in cattle, water buffaloes and other ruminants in different geographical regions, the fate and transport of infective stages following their release into the environment, as well as for improved strategies for the control and prevention of cryptosporidiosis and giardiasis, guided by molecular epidemiological studies.

Cryptosporidium parvum infection and associated risk factors in dairy calves in western France

This study was conducted to determine the prevalence and risk factors for Cryptosporidium infection in calf neonates on dairy farms in Normandy.

Fecal samples were randomly collected between July 2010 and September 2011 from 968 calves (7–21 days old) on 97 farms. Up to 10 calves were selected and sampled per farm, and feces examined for oocysts by microscopy. C. parvum oocyst shedding was scored semi-quantitatively (0–5). A questionnaire about calf-level care and management was completed, and mortality rates were obtained from the French national registration database (BDNI). Bivariable and multivariable analyses of potential risk factors for C. parvum oocyst shedding were conducted using generalized estimating equation (GEE) models (family = Binomial).Overall, 402 out of 968 calves (41.5%) were positive for oocysts, and 25.1% of animals had a shedding score >2. Seven of the 97 farms (7%) were negative for oocysts in all fecal samples. At the time of collection, 375 calves (39%) had diarrhea, and its prevalence strongly correlated with the score for C. parvum oocyst shedding (p < 0.0001). The mortality rate at 90 days was significantly greater for calves with high combined scores of diarrhea and shedding. Factors associated with the shedding of C. parvum were the Normande breed (odds ratio = 1.49; 95% confidence interval (CI): 0.93–2.37), dispensing of colostrum using a bucket (odds ratio = 1.37; 95% CI: 1.00–1.89), treatment with halofuginone (odds ratio = 0.46; 95% CI: 0.19–1.15) and feeding with fermented milk (odds ratio = 0.32; 95% CI: 0.17–0.63).

C. parvum is widespread among calves under 21 days old in dairy herds of western France. Shedding of C. parvum is associated with a high incidence of diarrhea and increased risk of mortality in young calves. This study identified some associated calf-level factors, although further investigations are necessary to determine appropriate measures that farmers and veterinary practitioners should take to reduce the prevalence of C. parvum.

Predominance of Cryptosporidium parvum genotype among diarrheic children from Egypt as an indicator for zoonotic transmission

Cryptosporidium is a genus of zoonotic pathogens transmissible from a variety of animals to humans and is a considerable public health concern. It is a significant cause of diarrheal disease in developing and industrialized nations. Cryptosporidium parvum and Cryptosporidium hominis are the main agents of cryptosporidiosis in humans. In this study we identified the genotypes of the Cryptosporidium isolates from clinical samples from diarrheic children using polymerase chain reaction (PCR) amplification and restriction fragment length polymorphism (RFLP) analyses of the TRAP-C2 gene (Thrompodin Related Adhesive Protein). A total of 430 fecal specimens from 1 to 14 years children were collected from inpatient and outpatient clinics of Benha University, Educational and Children Specialized Hospitals, Benha, Qalubyia, and were microscopically examined for Cryptosporidium spp. All infected samples were also analyzed using nested PCR. A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the (266-366 bp) of TRAP-C2 gene was also used to detect and identify Cryptosporidium spp. in PCR- positive samples. The results showed that 50 (11.63%) of the specimens were positive for Cryptosporidium spp. Genomic amplification and restriction digestion of the PCR products by BstETI, Hae III for TRAP-C2 gene restriction enzymes revealed that 82% (41/50) had C. parvum, 12% (6/50) had C. hominis, and three (3/50) samples (6%) had mixed infections. In conclusion, elevated prevalence of C. parvum, suggesting animal-human (zoonotic) transmission and further investigations are required to determine the subgenotypes of C. parvum to clarify the mode of transmission in order to improve the control measures.

Assessing calves as carriers of Cryptosporidium and Giardia with zoonotic potential on dairy and beef farms within a water catchment area by mutation scanning

In the present study, we undertook a molecular epidemiological survey of Cryptosporidium and Giardia in calves on three dairy and two beef farms within an open drinking water catchment area (Melbourne, Australia). Faecal samples (n = 474) were collected from calves at two time points (5 months apart) and tested using a PCR-based mutation scanning-targeted sequencing phylogenetic approach, employing regions within the genes of small subunit (SSU) of ribosomal RNA (designated partial SSU), 60 kDa glycoprotein (pgp60) and triose phosphate isomerase (ptpi) as genetic markers. Using partial SSU, the C. bovis, C. parvum, C. ryanae and a new genotype of Cryptosporidium were characterised from totals of 74 (15.6%), 35 (7.3%), 37 (7.8%) and 9 (1.9%) samples, respectively. Using pgp60, C. parvum genotype IIa subgenotype A18G3R1 was detected in 29 samples. Using ptpi, G. duodenalis assemblages A and E were detected in totals of 10 (2.1%) and 130 (27.4%) samples, respectively. The present study showed that a considerable proportion of dairy and beef calves in this open water catchment region excreted Cryptosporidium (i.e. subgenotype IIaA18G3R1) and Giardia (e.g. assemblage A) that are consistent with those infecting humans, inferring that they are of zoonotic importance. Future work should focus on exploring, in a temporal and spatial way, whether these parasites occur in the environment and water of the catchment reservoir.

Humans and cattle: a review of bovine zoonoses

Infectious disease prevention and control has been among the top public health objectives during the last century. However, controlling disease due to pathogens that move between animals and humans has been challenging. Such zoonotic pathogens have been responsible for the majority of new human disease threats and a number of recent international epidemics. Currently, our surveillance systems often lack the ability to monitor the human-animal interface for emergent pathogens. Identifying and ultimately addressing emergent cross-species infections will require a "One Health" approach in which resources from public veterinary, environmental, and human health function as part of an integrative system. Here we review the epidemiology of bovine zoonoses from a public health perspective.

Prevalence and molecular identification of cryptosporidium spp. In pre-weaned dairy calves in mashhad area, khorasan razavi province, iran

BACKGROUND

Cryptosporidium parvum is a zoonotic pathogen transmissible from a variety of animals to humans and is a considerable public health concern. Dairy cattle have been identified in numerous reports as a major source of environmental contamination with this pathogen. The aim of study was to detect and isolate the Cryptosporidium spp. from fecal samples of naturally infected pre-wean calves in the Mashhad area.

METHODS

Overall, 300 fecal specimens from 1 to 30 days pre-weaned calves were collected from 10 farms in the Mashhad area the capital center of the Khorasan Razavi Province, Iran and microscopically examined for Cryptosporidium spp. All infected samples were also analyzed using nested -PCR. A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the small-subunit (SSU) rRNA gene was also used to detect and identify Cryptosporidium spp. in PCR- positive samples.

RESULTS

Eighty five (28.3%) of the specimens were positive for Cryptosporidium spp. The prevalence of Cryptosporidium spp. in 8-14 days old and diarrheic calves were significantly higher than other groups. Restriction digestion of the PCR products by SspI, VspI restriction enzymes and sequence analysis revealed the presence of C. parvum bovine genotype in all isolates.

CONCLUSIONS

Our results suggest that pre-weaned calves are likely to be an important reservoir of zoonotic C. parvum.

Identification and molecular characterization of Cryptosporidium and Giardia in children and cattle populations from the province of Álava, North of Spain

The prevalence of and factors associated with the protozoan enteropathogens Cryptosporidium and Giardia have been investigated in selected children and cattle populations from the province of Álava (Northern Spain). The presence of these organisms was detected in fecal samples using commercially available coproantigen-ELISA (CpAg-ELISA) and immunochromatographic (ICT) assays. A total of 327 caregivers of children participants were asked to answer questions on risk factors potentially associated to the prevalence of Cryptosporidium and Giardia, including water-use practices, water sports and contact with domestic or pet animals. Molecular analyses were conducted using a nested-PCR technique to amplify the small-subunit (SSU) rRNA gene of Cryptosporidium and the triosephosphate isomerase (tpi) gene of Giardia. Cryptosporidium oocysts and Giardia cysts were found in 3 and 16 samples using the CpAg-ELISA, and in 5 and 9 samples using the ICT test, respectively. Cryptosporidium and Giardia were also found in 7 and 17 samples by CpAg-ELISA, and 4 and 14 samples by ICT, respectively, of 227 cattle fecal samples. The overall Cryptosporidium and Giardia infection prevalences, based on a Bayesian approach accounting for the imperfect sensitivities and specificities of both diagnostic tests, were estimated to 1.0% (95% BCI: 0.2%-2.8%) and 3.1% (1.5%-5.3%) in children and 3.0% (0.5%-9.2%) and 1.4% (0.0%-6.4%) in cattle, respectively. In humans, a single Cryptosporidium isolate was characterized as C. hominis. Of seven Giardia isolates, four were identified as assemblage B, two as assemblage A-II and one was a mixed assemblage B+A-II infection. No Cryptosporidium or Giardia isolates could be obtained from cattle samples. Although limited, these results seem to suggest that cattle are unlikely to be an important reservoir of zoonotic Cryptosporidium and/or Giardia in the province of Álava.

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).

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.

Parasite control in calves and growing heifers

Parasite control in calves and growing heifers results in animals that grow faster and remain healthier. Control programs revolve around reducing the parasites (infective stages) in the environment. In confinement, sanitation removes or reduces the number of infective stages (oocysts, cysts, and infective larvae) and the infection rate. On pasture one must resort to pasture management and parasite removal. The mites and lice are generally controlled by reducing or removing the populations on the animals, preventing the spread. Environmental control and manure management impact the fly populations.