Infection dynamics of Cryptosporidium bovis and Cryptosporidium ryanae in a Swedish dairy herd

Cryptosporidium and agriculture: A review

Cryptosporidiosis is a significant contributor to global foodborne and waterborne disease burden. It is a widespread cause of diarrheal diseases that affect humans and animals worldwide. Agricultural environments can become a source of contamination with Cryptosporidium species through faecal material derived from humans and animals. This review aims to report the main findings of scientific research on Cryptosporidium species related to various agricultural sectors, and highlights the risks of cryptosporidiosis in agricultural production, the contamination sources, the importance of animal production in transmission, and the role of farmed animals as hosts of the parasites. Agricultural contamination sources can cause water pollution in groundwater and different surface waters used for drinking, recreational purposes, and irrigation. The application of contaminated manure, faecal sludge management, and irrigation with inadequately treated water are the main concerns associated with foodborne and waterborne cryptosporidiosis related to agricultural activities. The review emphasizes the public health implications of agriculture concerning the transmission risk of Cryptosporidium parasites and the urgent need for a new concept in the agriculture sector. Furthermore, the findings of this review provide valuable information for developing appropriate measures and monitoring strategies to minimize the risk of infection.

Cryptosporidium infections in asymptomatic calves up to 4 months in Poland: a cross-sectional population study

Cattle cryptosporidiosis is noted worldwide with varied frequency of infection prevalence depending on geographical, environmental and husbandry factors. In this study, the prevalence of Cryptosporidium infections in cattle was determined on the basis of molecular results obtained by testing 1601 faecal samples collected from calves up to 4 months of age housed in all Polish provinces from 2014 to 2018. Detection and identification of Cryptosporidium species was performed at the 18 small subunit ribosomal RNA (18S rRNA) locus by conducting PCR-RFLP analysis of the amplified DNA fragments. The prevalence of Cryptosporidium infections in the cattle population was 45.3% (CI 95%: 42.8-47.7; 725/1601). The infected animals were housed on 233/267 (87.3%) of monitored farms with regional prevalence ranging from 27.8 to 62%. The restriction pattern of 18S rRNA amplicons for positive samples was characteristic of C. parvum, C. bovis, C. ryanae, C. andersoni, and unexpectedly also of C. baileyi and C. suis. Infections of C. bovis and C. ryanae prevailed in the studied cattle population relegating C. parvum to third in prevalence. Likewise, mixed infections caused by C. bovis and C. ryanae as well as C. parvum and C. bovis were observed. A relationship between the infecting parasite species and animal breed was found. For instance, C. parvum prevailed in Black and White lowland breed, C. ryanae in Limousine cattle and C. andersoni in dairy animals of mixed dairy breeds. Furthermore, differences in prevalence of particular parasite species between cattle breeds were also shown.

Dynamics of protozoal excretion in the faeces of calves during the first 28 days after arrival at the fattening farm indicate infection before regrouping and show poor temporal correlation with diarrhoea

BACKGROUND

Calves in dairy cattle production in Switzerland are transported to a fattening farm at the age of 3-5 weeks, and frequently suffer from diarrhoea within the first 14 days after arrival. To characterise the role of intestinal protozoa in this, we investigated the excretion dynamics of Eimeria, Cryptosporidium and Giardia during the first 28 days after the arrival and regrouping of calves at fattening farms.

METHODS

A total of 610 faecal samples from 122 calves (mean age 37.3 days; mean body weight 79.8 kg) were collected on seven different fattening farms during the first 28 days after the arrival and regrouping of the animals. The farms were visited between January and April (cold season; n = 4) and between June and August (warm season; n = 3). The samples were collected rectally on days 1, 4, 7, 14 and 28, assessed for consistency, and analysed using the McMaster method for quantitative determination of the number of Eimeria oocysts per gram of faeces (OPG), flotation for morphological differentiation of the unsporulated Eimeria oocysts, a concentration method for the semi-quantitative determination of Giardia cysts, and modified Ziehl-Neelsen staining for semi-quantitative determination of Cryptosporidium oocysts.

RESULTS

Overall, 50.8% (62/122) of the animals had diarrhoea during the study period. However, the faecal excretion of protozoal pathogens was neither associated with diarrhoea nor with body weight gain of the animals. Altogether, 90.2% (110/122) of the calves were Eimeria positive. Eimeria zuernii was excreted by 51 (41.8%) and Eimeria bovis by 68 (55.7%) animals. In the warm season more animals tested positive for Eimeria and OPGs were higher than in the cold season. There was no correlation between the age of the calves and the OPG values. Overall, 64.8% (79/122) of the calves excreted Eimeria oocysts within the first 7 days, indicating that they had been infected with the parasite on the dairy farm of origin. Eighty-nine calves (73.0%) excreted Giardia cysts, with more positive animals in the cold (80.3%) compared with the warm season (64.3%). Only Giardia duodenalis assemblage E was identified. Cryptosporidium oocysts were microscopically detected in 14 animals (11.5%) on five farms. Cryptosporidium spp. were present in a total of 12 animals, i.e. Cryptosporidium parvum in nine, Cryptosporidium ryanae in two, and Cryptosporidium bovis in one animal.

CONCLUSIONS

A better understanding of the temporal dynamics of protozoal infections in calves is helpful for the implementation of appropriate measures to protect the health of these animals at a critical phase in their lives. Our results indicate that factors other than those examined in the present study contributed to the onset of diarrhoea in the calves.

First report of Cryptosporidium andersoni and risk factors associated with the occurrence of Cryptosporidium spp. in pre-weaned native Korean calves with diarrhea

Cryptosporidium spp. are important enteric protozoan parasites that infect humans and other animals throughout the world. Cryptosporidium infection in cattle industry leads to substantial economic losses due to diarrhea, growth retardation, weight loss, and possibly death. Most studies have focused on C. parvum, and studies on other Cryptosporidium spp. and calf diarrhea are limited. Therefore, this study aimed to investigate the occurrence of Cryptosporidium spp. in pre-weaned calves, to determine the risk factors for Cryptosporidium spp. infection such as age and season, and to identify subtypes of C. parvum circulating in the Republic of Korea (ROK). A total of 510 fecal samples were collected from calves with diarrhea and divided by age and season. Cryptosporidium spp. were first screened using PCR targeting the small subunit (SSU) rRNA gene and further the 60-kDa glycoprotein gene for subtyping of C. parvum. Out of 510 fecal samples, 71 (13.9%) were positive for Cryptosporidium spp. in pre-weaned calves with diarrhea. C. andersoni (2.8%), C. bovis (30.9%), C. parvum (29.6%), and C. ryanae (36.6%) were identified. C. ryanae was the most predominant in calves in the ROK. Calf age was a significant risk factor for C. bovis (χ² = 13.83, P = 0.001), C. parvum (χ² = 7.57, P = 0.023), and C. ryanae (χ² = 20.18, P = 0.000) occurrence. Additionally, C. parvum was detected 3.1-fold more frequently in pre-weaned calves with diarrhea in fall (95% CI: 1.23-7.81; P = 0.016) than in spring, whereas C. ryanae was 8.9-fold more frequently detected in summer (95% CI: 1.65-48.68; P = 0.011) than in spring. Three subtypes (IIaA17G4R1, IIaA18G3R1, and IIaA20G3R1) of C. parvum were identified. Of them, IIaA17G4R1 was the most common, whereas IIaA20G3R1 was not previously detected in calves in the ROK. To our knowledge, this is the first report of C. andersoni in pre-weaned calves in the ROK. The occurrence of Cryptosporidium spp. appears to be age-dependent in calves. Season had a significant effect on the occurrence of C. parvum and C. ryanae. Taken together, C. bovis and C. ryanae along with C. parvum are detected in pre-weaned calves with diarrhea and these two pathogens should not be overlooked in the diagnosis of calf diarrhea.

Performance of diagnostic assays used to detect Cryptosporidium oocysts in faecal samples of cattle in Kuwait and genotyping of Cryptosporidium species

Backgroud

Cryptosporidium species are zoonotic protozoan parasites responsible for gastroenteritis in various animals and humans. The diagnosis of Cryptosporidium presents many challenges. This research attempted to match the diagnostic efficiency of the modified Ziehl–Neelsen technique (mZN), immunochromatographic assays (IC), and enzyme-linked immunosorbent assay (ELISA) for the detection of Cryptosporidium in faecal samples of cattle in Kuwait. In addition, polymerase chain reaction (PCR) was utilised to determine the predominant species infecting cattle in Kuwait and correlating the detected species with the results of different diagnostic tests used, the presence or absence of clinical signs, and the age group of the infected cattle.

Results

Of 400 analysed faecal samples, Cryptosporidium positive samples were 23%, 15.25%, and 14% using IC, ELISA, and mZN. IC had the highest sensitivity (74.07%), and mZN had the highest specificity (98.29%) using a composite reference standard (CRS) as a gold standard. The rapid IC test results in high false-positive results of cryptosporidiosis, whereas using mZN alone is insufficient to declare a negative faecal sample. Only 74.5% (35/47) of Cryptosporidium-positive samples by the three assays could be amplified by PCR. This study was the first to genotype Cryptosporidium in Kuwait. Cryptosporidium parvum (n = 26) was the dominant species detected from cattle samples, followed by C. andersoni (n = 6), C. bovis (n = 2), and C. raynae (n = 1). The findings showed a statistically relevant relationship between diarrhoea and the detection of Cryptosporidium spp. in faecal samples of cattle (p-value = 0.0003). Pre-weaned calves were the most vulnerable age group to Cryptosporidium spp. infection (p-value = 0.0007).

Conclusion

For screening of Cryptosporidium infection in faecal samples, antigen detection or PCR methods combined with one of the microscopy techniques should be used. Cryptosporidium parvum was the prepoderant Cryptosporidium spp. recovered from cattle samples in Kuwait followed by C. andersoni. Cryptosporidium parvum is a significant risk factor for diarrhoea in pre-weaned calves. However, further study is needed as many other causes of diarrhoea in calves must be ruled out before a diagnosis of Cryptosporidium diarrhoea can be made.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03435-w.

Epidemiological and Molecular Study of Cryptosporidium in Preweaned Calves in Kuwait

Simple Summary

Cryptosporidiosis is a global, zoonotic disease of concern. Cryptosporidium spp. can infect susceptible hosts via a main fecal–oral route due to cross-contamination of raw food and surface water from reservoir animals in the neighborhood, farms, or slaughter houses, besides some mechanical vectors, such as cockroaches and flies. Cryptosporidiumparvum alleles are the most common species infecting children, and its potential reservoir is cattle. Hence, understanding the epidemiology of Cryptosporidium spp. in preweaned calves, along with the diagnosis of the predominant species and subtypes infecting them, can play a role in preventing Cryptosporidium spp. spread in the environment. In this study, Cryptosporidiumparvum subtype IIaA15G2R1 was the most dominant Cryptosporidium spp. detected in preweaned calves in Kuwait. This subtype was recorded previously in Kuwaiti children suffering from diarrhea. Maintaining good personal hygiene in humans and reducing, controlling, or eliminating the causal risk factors in preweaned calves is a superb strategy for preventing and narrowing the spread of this disease.

Abstract

Cryptosporidium is a worldwide enteric protozoan parasite that causes gastrointestinal infection in animals, including humans. The most notable species is Cryptosporidium parvum because of its zoonotic importance; it is also the leading cause of cryptosporidiosis in preweaned calves. A cross-sectional study was conducted to determine the prevalence of Cryptosporidium infection, investigate the potential risk factors, and use molecular diagnosis to identify the predominant Cryptosporidium spp. in preweaned calves in Kuwait. Of 175 preweaned calves, Cryptosporidium antigens were detected in 58 (33.1%) using rapid lateral immunochromatography assay (IC). Calves less than one month of age (OR = 4.32, p = 0.0001) and poor hygiene (OR = 2.85, p = 0.0075) were identified as significant risk factors associated with Cryptosporidium infection. Molecular identification revealed that C. parvum (62.8%) was the dominant species infecting preweaned calves in Kuwait. In contrast, C. bovis and C. andersoni were recorded at 5.7% and 2.9%, respectively. All C. parvum gp60 nucleotide sequences were subtype IIaA15G2R1. Calves could be a source of C. parvum infection due to the similarity of the subtypes recorded previously in Kuwaiti children and preweaned calves in this study. Therefore, more research is needed to understand the Cryptosporidium transmission cycle in Kuwait.

Prevalence, risk factor and diversity of Cryptosporidium in cattle in Latvia

The epidemiology of Cryptosporidium spp. in Latvia was investigated by testing fecal samples from 926 animals aged from one day to 24 years for the presence of Cryptosporidium spp. oocysts. The samples were collected from 87 cattle farms and from four slaughterhouses, and analyzed by conventional and fluorescent microscopy, followed by Cryptosporidium species and C. parvum subtype differentiation. Moreover, using a questionnaire, we surveyed factors that could be relevant as risk factors of Cryptosporidium spp. infection on the farms. Cryptosporidium spp. were shed by 33.8% of the investigated cattle and at least one shedding animal was found on 77.8% of the farms. In the present study, all four Cryptosporidium species reported to commonly infect cattle and two additional Cryptosporidium species (C. scrofarum and C. ubiquitum) were identified. In addition, mix infections of C. parvum/C. bovis, C. bovis/C. ryanae, C. parvum/C. ryanae, C. parvum/C. andersoni and C. bovis/C. andersoni were observed. C. parvum and C. bovis was mostly prevalent in young animals (0-3 months old) and in addition, diarrhea associated with C. parvum infection was observed only in very young animals. Cryptosporidium andersoni and C. ryanae in age group 0-3 months was observed in low prevalence, while a higher proportion of animals with diarrhea associated with C. andersoni infection was observed in very young animals and with C. ryanae in animals age group 4-24 months. Eight previously described C. parvum subtypes were observed. The majority of the subtypes were in the IIa subtype family, while one subtype was identified from the IId subtype family. The most common subtype was IIaA15G2R1, which was found in 34.2% of the C. parvum successfully subtyped samples. The probability of Cryptosporidium spp. associated diarrhea in cattle decreased significantly with the age of the animals and a prolonged period during which calves were fed with milk.

Cross-Border Investigations on the Prevalence and Transmission Dynamics of Cryptosporidium Species in Dairy Cattle Farms in Western Mainland Europe

Cryptosporidium is an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis disease. In farms, the incidence of this disease is high in animals such as cows, leading to extensive economic loss in the livestock industry. Infected cows may also act as a major reservoir of Cryptosporidium spp., in particular C. parvum, the most common cause of cryptosporidiosis in these animals. This poses a risk to the trading of livestock, to other farms via breeding centres, and to human health. This study is a part of a global project aimed at strategies to tackle cryptosporidiosis. To reach this target, it was essential to determine whether prevalence was dependent on the studied countries or if the issue was borderless. Indeed, C. parvum occurrence was assessed across dairy farms in certain regions of Belgium, France, and the Netherlands. At the same time, the animal-to-animal transmission of the circulating C. parvum subtypes was studied. To accomplish this, we analysed 1084 faecal samples, corresponding to 57 dairy farms from all three countries. To this end, 18S rRNA and gp60 genes fragments were amplified, followed by DNA sequencing, which was subsequently used for detection and subtyping C. parvum. Bioinformatic and phylogenetic methods were integrated to analyse and characterise the obtained DNA sequences. Our results show 25.7%, 24.9% and 20.8% prevalence of Cryptosporidium spp. in Belgium, France, and the Netherlands respectively. Overall, 93% of the farms were Cryptosporidium positive. The gp60 subtyping demonstrated a significant number of the C. parvum positives belonged to the IIa allelic family, which has been also identified in humans. Therefore, this study highlights how prevalent C. parvum is in dairy farms and further suggests cattle as a possible carrier of zoonotic C. parvum subtypes, which could pose a threat to human health.

Development and Application of a gp60-Based Subtyping Tool for Cryptosporidium bovis

Cryptosporidium bovis is a common enteric pathogen in bovine animals. The research on transmission characteristics of the pathogen is hampered by the lack of subtyping tools. In this study, we retrieve the nucleotide sequence of the 60 kDa glycoprotein (GP60) from the whole genome sequences of C. bovis we obtained previously and analyze its sequence characteristics. Despite a typical structure of the GP60 protein, the GP60 of C. bovis had only 19.3–45.3% sequence identity to those of other Cryptosporidium species. On the basis of the gene sequence, a subtype typing tool was developed for C. bovis and used in the analysis of 486 C. bovis samples from dairy cattle, yaks, beef cattle, and water buffalos from China. Sixty-eight sequence types were identified from 260 subtyped samples, forming six subtype families, namely XXVIa to XXVIf. The mosaic sequence patterns among subtype families and the 121 potential recombination events identified among the sequences both suggest the occurrence of genetic recombination at the locus. No obvious host adaptation and geographic differences in the distribution of subtype families were observed. Most farms with more extensive sampling had more than one subtype family, and the dominant subtype families on a farm appeared to differ between pre- and post-weaned calves, indicating the likely occurrence of multiple episodes of C. bovis infections. There was an association between XXVId infection and occurrence of moderate diarrhea in dairy cattle. The subtyping tool developed and the data generated in the study might improve our knowledge of the genetic diversity and transmission of C. bovis.

CryptoGenotyper: A new bioinformatics tool for rapid Cryptosporidium identification

Cryptosporidium is a protozoan parasite that is transmitted to both humans and animals through zoonotic or anthroponotic means. When a host is infected with this parasite, it causes a gastrointestinal disease known as cryptosporidiosis. To understand the transmission dynamics of Cryptosporidium, the small subunit (SSU or 18S) rRNA and gp60 genes are commonly studied through PCR analysis and conventional Sanger sequencing. However, analyzing sequence chromatograms manually is both time consuming and prone to human error, especially in the presence of poorly resolved, heterozygous peaks and the absence of a validated database. For this study, we developed a Cryptosporidium genotyping tool, called CryptoGenotyper, which has the capability to read raw Sanger sequencing data for the two common Cryptosporidium gene targets (SSU rRNA and gp60) and classify the sequence data into standard nomenclature. The CryptoGenotyper has the capacity to perform quality control and properly classify sequences using a high quality, manually curated reference database, saving users' time and removing bias during data analysis. The incorporated heterozygous base calling algorithms for the SSU rRNA gene target resolves double peaks, therefore recovering data previously classified as inconclusive. The CryptoGenotyper successfully genotyped 99.3% (428/431) and 95.1% (154/162) of SSU rRNA chromatograms containing single and mixed sequences, respectively, and correctly subtyped 95.6% (947/991) of gp60 chromatograms without manual intervention. This new, user-friendly tool can provide both fast and reproducible analyses of Sanger sequencing data for the two most common Cryptosporidium gene targets.

The Age-Related Cryptosporidium Species Distribution in Asymptomatic Cattle from North-Western SPAIN

Simple Summary

An age-related distribution of Cryptosporidium species has been reported in cattle, with the pathogenic and zoonotic C. parvum being predominant in suckling calves, C. bovis and C. ryanae being predominant in post-weaned calves and C. andersoni being predominant in adults. However, variants to this pattern have recently been reported. Unravelling the age-related species distribution pattern in cattle from a particular region will allow determining those age classes posing a higher risk to public and animal health. Thus, fecal samples from asymptomatic cattle were collected in north-western Spain. Cryptosporidium detection and species identification was performed by molecular methods. Cryptosporidium prevalence was 16.7%; it significantly decreased with age. Cryptosporidium andersoni, C. bovis, C. occultus, C. parvum, C. ryanae and C. xiaoi were identified. Cryptosporidium parvum was predominant in calves younger than 1 month and C. bovis was predominant in the rest of the age groups. The presence of C. parvum in all age groups implies animal and public health concerns. The predominance of C. bovis in cattle older than 1 month supports the idea that the age-related pattern of Cryptosporidium species described in cattle is not fully consistent, and thus further studies are needed to identify those factors determining the species distribution.

Abstract

An age-related distribution of Cryptosporidium species has been reported in cattle, with C. parvum being predominant in suckling calves, C. bovis and C. ryanae being predominant in post-weaned calves and C. andersoni being predominant in adults. However, variants to this pattern have recently been reported. Thus, fecal samples (n = 594) from asymptomatic cattle were collected in north-western Spain. Animals were classified as <1 month (G1), 1–2 months (G2), 2–12 months (G3), 12–24 months (G4) and >2 years (G5). Cryptosporidium detection and species identification were performed by SSU rRNA PCR. Individual Cryptosporidium prevalence was 16.7%; it significantly decreased with age. Cryptosporidium parvum was predominant in G1 and C. bovis was predominant in the rest of the age classes; C. bovis and C. ryanae were especially prevalent in G2 and G3. Cryptosporidium occultus was not found in suckling calves. Finally, C. andersoni and C. xiaoi were occasionally detected in G5. The presence of C. parvum in all age classes implies significant animal and public health concerns. The predominance of C. bovis in cattle older than 1 month supports the idea that the age-related pattern of Cryptosporidium species described in cattle is not fully consistent, and thus further studies are still needed to identify those factors determining the species distribution.

Cryptosporidium parvum, Cryptosporidium ryanae, and Cryptosporidium bovis in samples from calves in Austria

Fecal samples of 177 calves of up to 180 days of age with diarrhea from 70 farms in Austria were examined to obtain information on the occurrence of Cryptosporidium species. Initially, all samples were examined by phase-contrast microscopy. Cryptosporidium-positive samples (55.4%; n = 98) were screened by gp60 PCR, resulting in 68.4% (n = 67) C. parvum-positive samples. The remaining 31 gp60-PCR-negative and the phase-contrast microscopy negative samples (n = 79) were screened by PCR targeting a 700 bp fragment of the 18S rRNA gene. Sequencing of the PCR products revealed the presence of C. parvum (n = 69), C. ryanae (n = 11), and C. bovis (n = 7). The latter two species have never been described in Austria. C. parvum-positive samples were genotyped at the gp60 gene locus, featuring four subtypes (IIaA15G2R1, IIaA21G2R1, IIaA19G2R1, IIaA14G1R1). The most frequently detected subtype IIaA15G2R1 (n = 52) was present in calves from 30 different farms. IIaA14G1R1 (n = 5) occurred on a single farm, subtype IIaA21G2R1 (n = 4) on two farms, and subtype IIaA19G2R1 (n = 4) on three farms. The results confirm the widespread occurrence of zoonotic C. parvum in diarrheic calves.