Cryptosporidium species in calves submitted for postmortem examination in England and Wales

Anti-Cryptosporidium oocysts polyclonal antibodies for cryptosporidiosis diagnosis and protection

Cryptosporidiosis is an intestinal infection that is triggered by the protozoan parasite Cryptosporidium spp. Cryptosporidium oocysts can spread from one host to another either through direct contact with infected hosts' faeces or through indirect means (consumption of contaminated water or food). Significant numbers of oocysts are produced as a result of the rapid growth of the parasite within the infected hosts. For proper care of cryptosporidiosis, a laboratory diagnosis is necessary. Therefore, this study aimed to produce anti-Cryptosporidium parvum (C. parvum) oocyst immunoglobulin (Ig)G polyclonal antibodies (pAbs). The produced pAbs were used in the detection of C. parvum oocysts antigens in stool and serum samples of infected calves. Moreover, pAbs were tested in protection of balb-c male mice from cryptosporidiosis infection. C. parvum oocysts were used in the preparation of antigens to be used in the immunization of New Zealand white rabbits. pAb was purified by ammonium sulphate precipitation method, caprylic acid purification method and diethylaminoethyl (DEAE) anion exchange chromatographic method. Sandwich enzyme-linked immunosorbent assay (ELISA) (using prepared pAb) scored higher sensitivity (85% and 95% for serum and stool samples) than that (80%) of microscopic examination of stool samples. Moreover, pAb significantly reduced the oocysts shedding, decreased inflammatory cytokines and enhanced the loss in the body weight of protected animals. The prepared pAb succeeded in the diagnosis of cryptosporidiosis in calves with high sensitivity either in the serum or stool samples. Our results indicated the usefulness of using the prepared pAb in protection against cryptosporidiosis.

CRISPR/Cas12a-powered immunosensor suitable for ultra-sensitive whole Cryptosporidium oocyst detection from water samples using a plate reader

Waterborne pathogens, such as Cryptosporidium parvum, pose a major threat to public health globally, and this requires screening of drinking and environmental water for low number of contaminating microbes. However, current detection approaches generally require trained experts with sophisticated instruments, and are not suitable for large-scale screening and rapid outbreak response. Recent advances in ultrasensitive CRISPR/Cas-based biosensing continue to expand the range of detectable molecular targets, however single microbes could not be directly detected so far, especially in environmental samples. Here, we report an ultrasensitive CRISPR/Cas12a-powered immunosensing method suitable for microbial detection which links antibody-based recognition with CRISPR/Cas12a-based fluorescent signal amplification through an antibody-DNA conjugate. This approach is shown here to detect whole 4 µm size Cryptosporidium parvum oocysts with a linear range from 6.25 - 1600 oocysts/mL, at a maximum sensitivity of single oocyst per sample. Its potential to apply to various complex sample matrices has also been demonstrated. After sample dilution by factor of 10, we were able to detect 10 oocysts from a back-wash mud samples from water treatment plate. This method uses the same experimental setup (plate reader) as a conventional ELISA assay thus reducing the need for microscopy-based identification of Cryptosporidium, which represents the gold-standard but requires high level expertise and time-consuming manual counting. This work highlights the potential of CRISPR/Cas-based biosensing for water quality assessment and ultrasensitive whole pathogen detection.

Cryptosporidium infections in terrestrial ungulates with focus on livestock: a systematic review and meta-analysis

Background

Cryptosporidium spp. are causative agents of gastrointestinal diseases in a wide variety of vertebrate hosts. Mortality resulting from the disease is low in livestock, although severe cryptosporidiosis has been associated with fatality in young animals.

Methods

The goal of this systematic review and meta-analysis was to review the prevalence and molecular data on Cryptosporidium infections in selected terrestrial domestic and wild ungulates of the families Bovidae (bison, buffalo, cattle, goat, impala, mouflon sheep, sheep, yak), Cervidae (red deer, roe deer, white-tailed deer), Camelidae (alpaca, camel), Suidae (boar, pig), Giraffidae (giraffes) and Equidae (horses). Data collection was carried out using PubMed, Scopus, Science Direct and Cochran databases, with 429 papers being included in this systematic analysis.

Results

The results show that overall 18.9% of ungulates from the investigated species were infected with Cryptosporidium spp. Considering livestock species (cattle, sheep, goats, pigs, horses and buffaloes), analysis revealed higher Cryptosporidium infection prevalence in ungulates of the Cetartiodactyla than in those of the Perissodactyla, with cattle (29%) being the most commonly infected farm animal.

Conclusions

Overall, the investigated domestic ungulates are considered potential sources of Cryptosporidium contamination in the environment. Control measures should be developed to reduce the occurrence of Cryptosporidium infection in these animals. Furthermore, literature on wild populations of the named ungulate species revealed a widespread presence and potential reservoir function of wildlife.

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

In order to investigate the infection dynamics of Cryptosporidium bovis and Cryptosporidium ryanae, a Swedish dairy farm known to be free of C. parvum was recruited for a one-year study. Fecal samples were collected every four weeks (a total of 13 occasions) from 20 randomly selected calves younger than 65 days. A total of 238 feces samples were collected directly from the rectum and then examined with immunofluorescence microscopy; those positive for Cryptosporidium spp. oocysts were further processed by molecular species determination. Oocysts were found in 92 samples, and in 72 of these the species was successfully determined: 87.5% C. bovis, 9.7% C. ryanae and 2.8% a mix of both species. No C. parvum was found. The prevalence of shedding calves was highest at ages 4 and 5 weeks; however, the feces with the highest oocyst per gram (OPG) were registered at 2-4 weeks of age. This is earlier than what has been found in most other studies, indicating that the infection dynamics of C. bovis/C. ryanae may be affected by the presence of C. parvum. The OPG for the positive calves ranged from 200 to 1.1 × 10⁶ (geometric mean 6.88 × 10³). The youngest calf in which C. bovis was identified was 5 days old, and the youngest calf in which C. ryanae was identified was 15 days old. Calves' housing type and seasonality were not associated with differences in the shedding of oocysts. Furthermore, there was no association between the presence of diarrhea and oocyst shedding.

Cryptosporidium outbreak in calves on a large dairy farm: Effect of treatment and the association with the inflammatory response and short-term weight gain

Cryptosporidium spp. infections in neonatal dairy calves can cause diarrhoea and, in rare cases, death. The infection is usually self-limiting, but halofuginone lactate (HL) can be used prophylactically. Calves (n=144) in the study were born during a 2-month period on one farm. A total of 901 serum and 767 faecal samples were collected. Based on HL treatment, the calves were divided into 3 groups: I) not treated, II) treated incorrectly (treatment started >48h after birth, or lasted <7days), and III) treated correctly (started <48h after birth, and lasted ≥7days). Over the 3-month observation period, 14.6% (n=21) of the calves died, of which most (67%) had not been treated with HL. Correctly performed treatment of cryptosporidiosis significantly delayed the onset of oocysts shedding (P<0.001) and reduced haptoglobin (HP) and serum amyloid A (SAA) concentrations in the second week of life. HP concentration and HL treatment were negatively associated with weight gain at 3months of age. Cryptosporidium positive faecal samples were significantly (P<0.001) more likely to be diarrhoeic but Giardia or Eimeria positive samples were not. Correct prophylactic treatment with HL delayed the shedding of Cryptosporidium oocysts and improved survival, but was negatively associated with weight gain. Incorrect treatment had a low impact on mortality and resembled no treatment regarding the proportion of calves shedding oocysts. Acute phase response (APR) in the second week of life seemed to be positively associated with shedding high amounts of Cryptosporidium oocysts.

Bovine cryptosporidiosis: impact, host-parasite interaction and control strategies

Gastrointestinal disease caused by the apicomplexan parasite Cryptosporidium parvum is one of the most important diseases of young ruminant livestock, particularly neonatal calves. Infected animals may suffer from profuse watery diarrhoea, dehydration and in severe cases death can occur. At present, effective therapeutic and preventative measures are not available and a better understanding of the host-pathogen interactions is required. Cryptosporidium parvum is also an important zoonotic pathogen causing severe disease in people, with young children being particularly vulnerable. Our knowledge of the immune responses induced by Cryptosporidium parasites in clinically relevant hosts is very limited. This review discusses the impact of bovine cryptosporidiosis and describes how a thorough understanding of the host-pathogen interactions may help to identify novel prevention and control strategies.

Cryptosporidiosis in Farmed Animals

Cryptosporidiosis was first identified as a disease of veterinary, rather than human medical, importance, and infection of farmed animals with different species of Cryptosporidium continues to be of veterinary clinical concern. This chapter provides insights into Cryptosporidium infection in a range of farmed animals – cattle, sheep, goats, pigs, cervids, camelids, rabbits, water buffalo and poultry – presenting not only an updated overview of the infection in these animals, but also information on clinical disease, infection dynamics and zoonotic potential. Although extensive data have been accrued on, for example, Cryptosporidium parvum infection in calves, and calf cryptosporidiosis continues to be a major veterinary concern especially in temperate regions, there remains a paucity of data for other farmed animals, despite Cryptosporidium infection causing significant clinical disease and also, for some species, with the potential for transmission of infection to people, either directly or indirectly.

Looking for Cryptosporidium: the application of advances in detection and diagnosis

The protozoan Cryptosporidium is a major public and animal health concern. Young children, immunocompromised people, and pre-weaning animals are especially vulnerable, but treatment options are limited and there is no vaccine. A laboratory diagnosis is required to confirm cases of cryptosporidiosis, and species and genotype determination is essential in distinguishing human from non-human sources, understanding transmission, and strengthening the epidemiological evidence for causative links in outbreaks. However, testing is not consistent, as demonstrated by investigation of a significant increase in cases in some European countries during 2012. Many methods employed are laborious and time-consuming; recent advances, translated into diagnostic assays, can improve testing and facilitate typing to support clinical and environmental investigations.

Occurrence and diversity of Giardia duodenalis assemblages in livestock in the UK

Summary

Giardia duodenalis is a common intestinal parasite in humans and a wide range of livestock species. It is a genetically heterogeneous parasite that has been characterized in seven distinct genetic assemblages or cryptic species, and molecular markers can be used to differentiate both animal-specific and potentially zoonotic genotypes. Little is known about G. duodenalis and the range of assemblages occurring in domestic livestock species in the UK. Here, we present data on the occurrence and molecular diversity of G. duodenalis detected in the faeces or large intestinal contents of cattle, sheep, pigs, goats and camelids from farms in the north-west of England. Both healthy and clinically diseased animals were included in the survey. The presence of Giardia spp. and assemblages was determined by sequencing of the small-subunit ribosomal RNA gene. The potential association of infection with various clinical and epidemiological parameters was studied in cattle using both univariate and multivariate analyses. Giardia spp. were detected in 127 (34.3%) of the 370 animals tested. G. duodenalis assemblage E was found to be predominant in cattle and sheep, followed by assemblage A. Mixed infections with assemblages A and E were also detected. Interestingly, some cattle, sheep and pigs were found to be infected with more unexpected assemblages (C, D, F). Pre-weaned calves were more likely to test positive than adult animals, but no association between the occurrence of overt intestinal disease and G. duodenalis infection was detected. The common occurrence of assemblage A and the finding of unusual assemblages in atypical hosts suggest that in future, a multilocus analysis should be used to confirm the actual diversity of G. duodenalis in livestock and the presence of potentially zoonotic genotypes. These data also suggest that there is a need to re-evaluate the clinical significance of G. duodenalis infection in livestock.

A whole water catchment approach to investigating the origin and distribution of Cryptosporidium species

AIMS

Investigating the distribution and origin of Cryptosporidium species in a water catchment affected by destocking and restocking of livestock as a result of a foot and mouth disease epidemic.

METHODS AND RESULTS

Surface water, livestock and wildlife samples were screened for Cryptosporidium and oocysts characterised by sequencing SSU rRNA and COWP loci, and fragment analysis of ML1, ML2 and GP60 microsatellite loci. Oocyst concentrations in water samples (0-20.29 per 10 l) were related to rainfall events, amount of rainfall and topography. There was no detectable impact from catchment restocking. Cryptosporidium spp. found in water were indicative of livestock (Cryptosporidium andersoni and Cryptosporidium parvum) and wildlife (novel genotypes) sources. However, C. andersoni was not found in any animals sampled. Calf infections were age related; C. parvum was significantly more common in younger animals (<4 weeks old). Older calves shared Cryptosporidium bovis, Cryptosporidium ryanae and C. parvum. Wildlife shed C. parvum, Cryptosporidium ubiquitum, muskrat genotype II and deer genotype.

CONCLUSIONS

Several factors affect the occurrence of Cryptosporidium within a catchment. In addition to farmed and wild animal hosts, topography and rainfall patterns are particularly important.

SIGNIFICANCE AND IMPACT OF THE STUDY

These factors must be considered when undertaking risk-based water safety plans.

Efficacy of halofuginone lactate in the prevention of cryptosporidiosis in dairy calves

To evaluate the efficacy of halofuginone lactate (Halocur; Intervet) when used prophylactically against cryptosporidiosis in dairy calves, 513 Holstein heifer calves were randomly distributed between two experimental groups. Those in the treatment group (n=259) received 0.1 mg halofuginone base per kg bodyweight daily in a 10 ml solution, for the first seven days following birth, while those in the control group (n=254) received an equal volume of a placebo solution. Faecal samples were collected weekly from all calves until three weeks of age to test for Cryptosporidium oocysts and to assess the diarrhoeal status. Growth parameters of the calves were also recorded at approximately four months of age. Calves that received halofuginone were significantly less likely to shed Cryptosporidium oocysts during the course of the study than placebo-treated calves (odds ratio 0.6, 95 per cent confidence interval 0.4 to 0.9, P=0.009). Mean growth measurements of calves in the treated group were consistently higher than those of the control calves (hipometer-derived P=0.052, wither height P=0.097) and mortality was lower in the treated group (P=0.07). However, these differences were not statistically significant (P>0.05). No association was found between the prophylactic use of halofuginone and the incidence of calf diarrhoea.