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

Emerging therapeutic avenues against Cryptosporidium: A comprehensive review

Cryptosporidium is among the top causes of life-threatening diarrheal infection in public health and livestock sectors. Despite its high prevalence and economic importance, currently, there is no vaccine. Control of this protozoan is difficult due to the excretion of many resistant oocysts in the feces of the infected host, which contaminate the environment. Paromomycin shows inconsistent results and isn't considered a reliable therapy for cryptosporidiosis. Nitazoxanide (NTZ), the only FDA-approved drug against this parasite, is less productive in impoverished children and PLWHA (people living with HIV/AIDS). The absence of mitochondria and apicoplast, its unique location inside enterocytes separated by parasitophorous vacuole, and, most importantly, challenges in its genetic manipulations are some hurdles to the drug-discovery process. A library of compounds has been tested against Cryptosporidium during in vitro and in vivo trials. However, there has still not been sufficient success in finding the drug of choice against this parasite. Recent genome editing technologies based on CRISPR/Cas-9 have explored the functions of the vital genes by producing transgenic parasites that help to screen a collection of compounds to find target-specific drugs, provided the sufficient availability of in vitro culturing platforms, efficient transfection methods, and analytic techniques. The use of herbal remedies against Cryptosporidium is also an emerging area of interest with sufficient clinical success due to enhanced concern regarding anthelmintic resistance. Here, we highlighted present treatment options with their associated limitations, the use of genetic tools and natural products against it to find safe, effective, and inexpensive drugs to control the ever-increasing global burden of this disease.

Association of clinical respiratory disease signs and lower respiratory tract bacterial pathogens with systemic inflammatory response in preweaning dairy calves

This study investigated the potential associations between 3 acute phase proteins (APP)-haptoglobin, serum amyloid A-and fibrinogen, clinical signs of respiratory disease, and the presence of bacterial pathogens in the lower respiratory tract (LRT) of preweaning dairy calves. This cross-sectional study included 150 preweaning calves (2-86 d old) from 15 large dairy herds in Estonia. Tracheobronchial lavage, blood, and fecal samples were collected from 5 calves showing clinical signs indicative of LRT disease, and samples from 5 calves without clinical signs of LRT disease per herd. All samples collected from these calves were analyzed for concentrations of systemic APP, LRT bacteria, and intestinal pathogens. Heifer blood and bulk tank milk samples were collected for the detection of disease-specific antibodies against bovine herpesvirus 1, bovine viral diarrhea virus, bovine respiratory syncytial virus, and Mycoplasma bovis. Mixed-effects linear regression models were used to analyze the associations of clinical respiratory disease signs and LRT bacteria with APP. Increased plasma fibrinogen concentrations in calves were associated with higher rectal temperature (>39.5°C), increased respiratory rate (>50 breaths/min), and coughing. Increased serum amyloid A concentrations were associated with higher rectal temperature (>39.5°C) and respiratory rate between 40 and 50 breaths/min. Calves with the presence of fecal Cryptosporidium spp. and rectal temperature of 39°C and above had increased serum haptoglobin concentrations. Increased fibrinogen concentrations were associated with the presence of Pasteurella multocida in the calf LRT, whereas increased concentrations of fibrinogen and serum amyloid A were associated with the presence of Trueperella pyogenes. In conclusion, APP showed variable associations with clinical signs of respiratory disease and LRT bacteria. Plasma fibrinogen concentration could be used as a complementary calf-side test to assess systemic inflammation caused by LRT bacteria such as Pasteurella multocida and Trueperella pyogenes in preweaning dairy calves.

Associations of neonatal acute phase response with first lactation performance in dairy cows

During the first 3 wk of life, the immune system of newborn ruminants starts to work, as indicated by fluctuations in the concentrations of proinflammatory cytokines and acute phase proteins (APP). They have been shown to be markers for short and long-term weight gain in ruminants. This observational study investigated these proteins as possible indicators of first lactation performance of dairy cows. A total of 117 dairy calves from a single farm were enrolled in the study. Serum and fecal samples were taken once a week for the first 3 wk of life. Cryptosporidium spp. infection and its treatment were monitored and accounted for in statistical analysis. The concentrations of the APP serum amyloid A (SAA) and haptoglobin (Hp), and the proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed in serum. After the first lactation, health and performance data of the cows were retrieved, and associations between APP and cytokine concentrations with first lactation outcomes were investigated through linear and logistic regression. This study found a negative association between the concentration of Hp in the second week of life and average daily weight gain at one year. The SAA concentration measured during the second and third weeks of life was positively associated with age at first calving. IL-6, SAA, and Hp measured in the second week of life were positively associated with calving to conception interval. The concentrations of IL-6 and TNF-α during the first week of life were associated with higher odds of reproductive issues during the first lactation period. These markers can be used to help understand underlying processes that influence animal health and production. In conclusion, inflammatory responses during the first week of life are related to reproductive success, whereas the second and third weeks of life seem to influence the future productive performance in dairy cows.

MCT-Dependent Cryptosporidium parvum-Induced Bovine Monocyte Extracellular Traps (METs) under Physioxia

The apicomplexan protozoan parasite Cryptosporidium parvum is responsible for cryptosporidiosis, which is a zoonotic intestinal illness that affects newborn cattle, wild animals, and people all over the world. Mammalian monocytes are bone marrow-derived myeloid leukocytes with important defense effector functions in early host innate immunity due to their ATP purinergic-, CD14- and CD16-receptors, adhesion, migration and phagocytosis capacities, inflammatory, and anti-parasitic properties. The formation of monocyte extracellular traps (METs) has recently been reported as an additional effector mechanism against apicomplexan parasites. Nonetheless, nothing is known in the literature on METs extrusion neither towards C. parvum-oocysts nor sporozoites. Herein, ATP purinergic receptor P2X1, glycolysis, Notch signaling, and lactate monocarboxylate transporters (MCT) were investigated in C. parvum-exposed bovine monocytes under intestinal physioxia (5% O₂) and hyperoxia (21% O₂; most commonly used hyperoxic laboratory conditions). C. parvum-triggered suicidal METs were confirmed by complete rupture of exposed monocytes, co-localization of extracellular DNA with myeloperoxidase (MPO) and histones (H1-H4) via immunofluorescence- and confocal microscopy analyses. C. parvum-induced suicidal METs resulted not only in oocyst entrapment but also in hindered sporozoite mobility from oocysts according to scanning electron microscopy (SEM) analyses. Early parasite-induced bovine monocyte activation, accompanied by membrane protrusions toward C. parvum-oocysts/sporozoites, was unveiled using live cell 3D-holotomographic microscopy analysis. The administration of NF449, an inhibitor of the ATP purinergic receptor P2X1, to monocytes subjected to varying oxygen concentrations did not yield a noteworthy decrease in C. parvum-induced METosis. This suggests that the cell death process is not dependent on P2X1. Additionally, blockage of glycolysis in monocyte through 2-deoxy glucose (2-DG) inhibition reduced C. parvum-induced METosis but not significantly. According to monocyte energetic state measurements, C. parvum-exposed cells neither increased extracellular acidification rates (ECAR) nor oxygen consumption rates (OCR). Lactate monocarboxylate transporters (MCT) inhibitor (i.e., AR-C 141990) treatments significantly diminished C. parvum-mediated METs extrusion under physioxic (5% O₂) condition. Similarly, treatment with either DAPT or compound E, two selective Notch inhibitors, exhibited no significant suppressive effects on bovine MET production. Overall, for the first time, we demonstrate C. parvum-mediated METosis as P2X1-independent but as an MCT-dependent defense mechanism under intestinal physioxia (5% CO₂) conditions. METs findings suggest anti-cryptosporidial effects through parasite entrapment and inhibition of sporozoite excystation.

Past, current, and potential treatments for cryptosporidiosis in humans and farm animals: A comprehensive review

The intracellular protozoan parasite of the genus Cryptosporidium is among the leading causes of waterborne diarrheal disease outbreaks throughout the world. The parasite is transmitted by ingestion of infective oocysts that are highly stable in the environment and resistant to almost all conventional disinfection methods and water treatments. Control of the parasite infection is exceedingly difficult due to the excretion of large numbers of oocysts in the feces of infected individuals that contaminate the environment and serve as a source of infection for susceptible hosts including humans and animals. Drug development against the parasite is challenging owing to its limited genetic tractability, absence of conventional drug targets, unique intracellular location within the host, and the paucity of robust cell culture platforms for continuous parasite propagation. Despite the high prevalence of the parasite, the only US Food and Drug Administration (FDA)-approved treatment of Cryptosporidium infections is nitazoxanide, which has shown moderate efficacy in immunocompetent patients. More importantly, no effective therapeutic drugs are available for treating severe, potentially life-threatening cryptosporidiosis in immunodeficient patients, young children, and neonatal livestock. Thus, safe, inexpensive, and efficacious drugs are urgently required to reduce the ever-increasing global cryptosporidiosis burden especially in low-resource countries. Several compounds have been tested for both in vitro and in vivo efficacy against the disease. However, to date, only a few experimental compounds have been subjected to clinical trials in natural hosts, and among those none have proven efficacious. This review provides an overview of the past and present anti-Cryptosporidium pharmacotherapy in humans and agricultural animals. Herein, we also highlight the progress made in the field over the last few years and discuss the different strategies employed for discovery and development of effective prospective treatments for cryptosporidiosis.

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.

Faecal microbiota in two-week-old female dairy calves during acute cryptosporidiosis outbreak - Association with systemic inflammatory response

In the present study, relationships between the intestinal microbiota and innate immunity response, acute cryptosporidiosis, and weight gain in female dairy calves were investigated. A total of 112 calves born during a natural outbreak of cryptosporidiosis on one dairy farm was included in the study. Microbiota composition was analysed by means of 16S ribosomal RNA gene amplicon sequencing from faecal samples collected during the second week of life, while the status of Cryptosporidium spp. infection was determined using immunofluorescence. Serum samples from the second week of life were colourimetrically analysed for the following markers of acute inflammation: acute-phase proteins (serum amyloid A and haptoglobin) and pro-inflammatory cytokines (interleukin-1 beta, interleukin-6, and tumour necrosis factor-alpha). Statistical analyses were performed using random forest analysis, variance-partitioning, and negative binomial regression. The faecal microbiota of the two-week old calves was composed of the phyla Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria (in order of decreasing abundance). Microbial diversity, measured in terms of the Shannon index, increased with the age of the calves and decreased if a high count of Cryptosporidium spp. oocysts was found in the faeces. Fusobacterium was positively associated with Cryptosporidium spp. oocyst count and serum amyloid A concentration. Peptostreptococcus was positively associated with haptoglobin and serum amyloid A concentrations, and negatively associated with average daily weight gain at 9 months of age. The markers of innate immunity, in combination with age, explained 6% of the microbial variation. These results suggest that some components of the intestinal microbiota may have a long-lasting negative effect on animal growth through the stimulation of the systemic innate immune response.

Velásquez Z, Borggrefe T, Gärtner U, Kamena F, Taubert A, Hermosilla C. ATP Purinergic Receptor P2X1-Dependent Suicidal NETosis Induced by Cryptosporidium parvum under Physioxia Conditions

Cryptosporidiosis is a zoonotic intestinal disease that affects humans, wildlife, and neonatal cattle, caused by Cryptosporidium parvum. Neutrophil extracellular traps (NETs), also known as suicidal NETosis, are a powerful and ancient innate effector mechanism by which polymorphonuclear neutrophils (PMN) battle parasitic organisms like protozoa and helminths. Here, C. parvum oocysts and live sporozoites were utilized to examine suicidal NETosis in exposed bovine PMN under both 5% O₂ (physiological conditions within small intestinal tract) and 21% O₂ (normal hyperoxic conditions in research facilities). Both sporozoites and oocysts induced suicidal NETosis in exposed PMN under physioxia (5% O₂) and hyperoxia (21% O₂). Besides, C. parvum-induced suicidal NETosis was affirmed by total break of PMN, co-localization of extracellular DNA decorated with pan-histones (H1A, H2A/H2B, H3, H4) and neutrophil elastase (NE) by means of confocal- and immunofluorescence microscopy investigations. C. parvum-triggered NETs entrapped sporozoites and impeded sporozoite egress from oocysts covered by released NETs, according to scanning electron microscopy (SEM) examination. Live cell 3D-holotomographic microscopy analysis visualized early parasite-induced PMN morphological changes, such as the formation of membrane protrusions towards C. parvum while undergoing NETosis. Significant reduction of C. parvum-induced suicidal NETosis was measured after PMN treatments with purinergic receptor P2X1 inhibitor NF449, under both oxygen circumstances, this receptor was found to play a critical role in the induction of NETs, indicating its importance. Similarly, inhibition of PMN glycolysis via 2-deoxy glucose treatments resulted in a reduction of C. parvum-triggered suicidal NETosis but not significantly. Extracellular acidification rates (ECAR) and oxygen consumption rates (OCR) were not increased in C. parvum-exposed cells, according to measurements of PMN energetic state. Treatments with inhibitors of plasma membrane monocarboxylate transporters (MCTs) of lactate failed to significantly reduce C. parvum-mediated NET extrusion. Concerning Notch signaling, no significant reduction was detected after PMN treatments with two specific Notch inhibitors, i.e., DAPT and compound E. Overall, we here describe for the first time the pivotal role of ATP purinergic receptor P2X1 in C. parvum-mediated suicidal NETosis under physioxia (5% O₂) and its anti-cryptosporidial properties.

Diarrhoea outbreak caused by coinfections of Cryptosporidium parvum subtype IIdA20G1 and rotavirus in pre-weaned dairy calves

Diarrhoea is one of the most important syndromes in neonatal calves. In industrialized nations with intensive animal farming, Cryptosporidium spp. and rotavirus are primary causes of calf diarrhoea, but the role of these and other enteric pathogens is not clear in China. In November and December 2018, a diarrhoea outbreak was identified in over 150 pre-weaned calves on a dairy farm in Heilongjiang Province, northeast China and approximately 60 calves died. To determine the cause of the outbreak, we analyzed 131 faecal samples collected from pre-weaned calves (0-2 months) during (n = 114) and after the outbreak (n = 17). Initially, 10 diarrheic samples during the outbreak and 10 non-diarrheic samples after the outbreak were screened for rotavirus, coronavirus, Escherichia coli K99 and Cryptosporidium parvum by using an enzymatic immunoassay (EIA). In addition, 81 other samples were tested specifically for rotavirus by EIA, and all 131 samples were analyzed for Cryptosporidium spp., Giardia duodenalis and Enterocytozoon bieneusi by PCR. The initial EIA analysis identified C. parvum (8/10) and rotavirus (5/10) as the dominant pathogens in calves during the outbreak, while both pathogens were detected at lower frequency after the outbreak (2/10 and 1/10, respectively). Further PCR analyses indicated that the occurrence of C. parvum infections in calves was significantly higher during the outbreak (75.4%, 86/114) than after the outbreak (11.8%, 2/17; odds ratio [OR] = 23.0), and was significantly associated with the occurrence of watery diarrhoea (OR = 15.7) and high oocyst shedding intensity. All C. parvum isolates were identified as subtype IIdA20G1. Among other pathogens analyzed, the overall prevalence of rotavirus, G. duodenalis and E. bieneusi was 19.8% (20/101), 38.9% (51/131) and 42.0% (55/131) in calves, respectively, without significant differences during and after the outbreak. Among the three pathogens, only the rotavirus infection was associated with diarrhoea in calves. More importantly, coinfections of C. parvum and rotavirus were significantly associated with the occurrence of watery diarrhoea in calves and were seen only during the outbreak. Thus, C. parvum subtype IIdA20G1 and rotavirus appeared to be responsible for this diarrhoea outbreak. Control measures should be implemented to effectively prevent the concurrent transmission of these enteric pathogens in pre-weaned dairy calves in China.

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.

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.

Haptoglobin and its association with naturally occurring diseases in Holstein heifer calves

ABSTRACT The present study evaluated the use of haptoglobin (Hp) as an indicator of health and performance in 166 Holstein heifer calves reared in an intensive production system. Calves were evaluated at D6-9; D10-13; D20-23; D35-38 and D65-68, corresponding to the days of life. The absence or presence of diseases was evaluated by physical examination and classification of scores. The performance parameters evaluated were body weight, height at withers and hind width. Hp was measured by spectrophotometric technique. The highest prevalence of diarrhea (59.4%; 98/165) was observed in D10-13, bovine respiratory disease (BRD) was on D35-38 (25.8%; 42/163), and umbilical inflammations in D6-D9 (7.8%; 13/166). Highest values of Hp were observed in animals with diarrhea (P=0.02), and umbilical inflammation (P=0.057), in comparison with the group of healthy calves. A significant negative correlation was observed between Hp and performance index. This protein presented an important relation with diarrhea and performance of the calves, opening perspectives on its utilization as a biomarker of diseases.

Efficacy of halofuginone products to prevent or treat cryptosporidiosis in bovine calves: a systematic review and meta-analyses

A prior systematic review on the efficacy of halofuginone (HFG) treatment to prevent or treat cryptosporidiosis in bovine calves was inconclusive. We undertook an updated synthesis and meta-analyses on key outcomes for the treatment of calves with HFG. Evaluated outcomes were oocyst shedding, diarrhoea, mortality and weight gain. Experiments had to describe results for same age animals in contemporary arms. Most doses were 100-150 mcg kg-1 day-1. Results were subgrouped by study design, experiments with the lowest risk of bias and lack of industry funding. Eighteen articles were found that described 25 experiments. Most evidence came from randomized controlled trials in Europe. Significantly lower incidence of oocyst shedding, diarrhoea burden and mortality was reported when treatment started before calves were 5 days old. Most studies reported on outcomes for animals up to at least 28 days old. Publication bias was possible in all outcomes and seemed especially likely for diarrhoea outcomes. Beneficial results when HFG treatment was initiated in calves older than 5 days were also found. Prophylactic treatment to prevent cryptosporidiosis is effective in preventing multiple negative outcomes and is beneficial to calf health and will result in a reduction of environmental contamination by Cryptosporidium oocysts.

Cryptosporidiosis outbreak caused by Cryptosporidium parvum subtype IIdA20G1 in neonatal calves

Cryptosporidium parvum is a major zoonotic pathogen responsible for outbreaks of severe diarrhoea in humans and calves. Almost all investigations of cryptosporidiosis outbreaks caused by C. parvum have focused on its IIa subtype family in industrialized nations. From December 2018 to April 2019, approximately 200 neonatal calves on a large cattle farm in Hebei Province, China, were diagnosed with watery diarrhoea and over 40 died. To investigate the cause of the outbreak, faecal samples were taken during and after the outbreak from neonatal calves of ≤4 weeks of age (n = 40 and n = 56) and older calves of 4-24 weeks of age (n = 79 and n = 38). A total of 18 faecal samples collected from ill calves at the peak of the outbreak were analysed for four common enteric pathogens using an enzymatic immunoassay (EIA). In addition, 75 samples from neonatal calves were tested for rotavirus by EIA. All samples were analysed for Cryptosporidium spp. using PCR and sequencing techniques. Of the initial 18 samples from sick calves, ten were positive for C. parvum, five for rotavirus, and one for coronavirus. The overall prevalence of rotavirus in neonatal calves was 20.0% (15/75), with no significant differences during and after the outbreak. In contrast, Cryptosporidium parvum infections were significantly higher during the outbreak (60.0%, 24/40) than after the outbreak (30.4%, 17/56; p = .004). Cryptosporidium parvum infection was associated with the presence of watery diarrhoea in neonatal calves (OR = 11.19), while no association was observed between C. bovis infection and diarrhoea. All C. parvum isolates were identified as subtype IIdA20G1. This is one of the few reports of outbreaks of severe diarrhoea caused by C. parvum IId subtypes in calves. More attention should be directed towards the dissemination of C. parvum in China.

Cryptosporidium Species and C. parvum Subtypes in Farmed Bamboo Rats

Bamboo rats (Rhizomys sinensis) are widely farmed in Guangdong, China, but the distribution and public health potential of Cryptosporidium spp. in them are unclear. In this study, 724 fecal specimens were collected from bamboo rats in Guangdong Province and analyzed for Cryptosporidium spp. using PCR and sequence analyses of the small subunit rRNA gene. The overall detection rate of Cryptosporidium spp. was 12.2% (88/724). By age, the detection rate in animals under 2 months (23.2% or 13/56) was significantly higher than in animals over 2 months (11.2% or 75/668; χ² = 6.95, df = 1, p = 0.0084). By reproduction status, the detection rate of Cryptosporidium spp. in nursing animals (23.1% or 27/117) was significantly higher than in other reproduction statuses (6.8% or 4/59; χ² = 7.18, df = 1, p = 0.0074). Five Cryptosporidium species and genotypes were detected, including Cryptosporidium bamboo rat genotype I (n = 49), C. parvum (n = 31), Cryptosporidium bamboo rat genotype III (n = 5), C. occultus (n = 2), and C. muris (n = 1). The average numbers of oocysts per gram of feces for these Cryptosporidium spp. were 14,074, 494,636, 9239, 394, and 323, respectively. The genetic uniqueness of bamboo rat genotypes I and III was confirmed by sequence analyses of the 70 kDa heat shock protein and actin genes. Subtyping C. parvum by sequence analysis of the 60 kDa glycoprotein gene identified the presence of IIoA15G1 (n = 20) and IIpA6 (n = 2) subtypes. The results of this study indicated that Cryptosporidium spp. are common in bamboo rats in Guangdong, and some of the Cryptosporidium spp. in these animals are known human pathogens.

Cryptosporidium Infections in Africa-How Important Is Zoonotic Transmission? A Review of the Evidence

Cryptosporidium, a protozoan parasite in the phylum Apicomplexa, is the etiological agent of cryptosporidiosis, an intestinal infection characterized by profuse watery diarrhea. Over 30 species of Cryptosporidium are recognized, some host specific whereas others infect a broader host range. Cryptosporidium hominis and Cryptosporidium parvum are the species most commonly associated with human infection; C. hominis is largely associated only with human infections, but C. parvum is also associated with infection in animals, especially young ruminants. In some regions, cryptosporidiosis is a serious veterinary problem, particularly for calves, and lambs. Many outbreaks of human cryptosporidiosis have been associated with zoonotic transmission following contact with infected animals. In Africa, where cryptosporidiosis is a major contributor to pediatric morbidity and mortality, evidence suggests transmission is principally anthroponotic. Given the frequent close contact between humans and animals in Africa, the apparent predominance of human-to-human transmission is both interesting and puzzling. In this article, after a brief "text book" introduction to the parasite, we consider in separate sections the different aspects of relevance to Cryptosporidium transmission in African countries, describing different aspects of the various species and subtypes in human and animal infections, considering livestock management practices in different African countries, and looking for any characteristic "hot spots" where zoonotic transmission has apparently occurred. Studies where transmission networks have been investigated are particularly relevant. Finally, in a separate section, we try to gather these different strands of evidence together in order to assess the reasons behind the apparent predominance of anthroponotic transmission in Africa. Reviewing the available evidence provides an opportunity to re-think transmission pathways, not only in Africa but also elsewhere, and also to pose questions. Does the predominance of human-to-human transmission in Africa reflect a relative absence of zoonotic C. parvum in African livestock? Are Africans less susceptible to zoonotic Cryptosporidium infection, perhaps resulting from early immunostimulation by C. hominis or due to inherent genetic traits? Is the African environment-in all its variety-simply more detrimental to oocyst survival? Will the so-called hypertransmissible subtypes, currently relatively rare in Africa, be introduced from Europe or elsewhere, and, if so, will they fade out or establish and spread? Our intention with this manuscript is not only to summarize and consolidate diverse data, thereby providing an overview of data gaps, but also to provide food for thought regarding transmission of a parasite that continues to have a considerable impact on both human and animal health.

Cryptosporidium and Giardia in Ruminants

Cryptosporidium and Giardia are ubiquitous protozoan parasites that infect a broad range of vertebrate hosts, including domestic and wild animals as well as humans. Both parasites are of medical and veterinary importance. Infections with Cryptosporidium and Giardia in ruminants are associated with diarrhea outbreaks, mainly in young animals. Ruminants are potential sources of infection for humans because some species of Cryptosporidium and assemblages of Giardia duodenalis have been isolated from both ruminants and humans. Knowledge of these parasites has greatly expanded in the last 2 decades from simple microscopic observations of organisms to the knowledge acquired from molecular tools.

Outbreak of cryptosporidiosis due to Cryptosporidium parvum subtype IIdA19G1 in neonatal calves on a dairy farm in China

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An outbreak of severe diarrhea was caused by Cryptosporidium parvum IIdA19G1 in dairy calves.

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Concurrence of rotavirus was present, but not as a significant cause of diarrhea in the investigation.

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Cryptosporidium parvum infection was associated with the occurrence of watery diarrhea in calves.

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Cryptosporidium ryanae and Cryptosporidium bovis infections were associated with the occurrence of moderate diarrhea.

Neonatal diarrhea is one of the most important syndromes in dairy cattle. Among enteropathogens, Cryptosporidium spp. are primary causes of diarrhea, but outbreaks due to cryptosporidiosis are rarely reported in cattle. From January to April in 2016, severe diarrhea was observed in over 400 neonatal dairy calves on a large dairy farm in Jiangsu Province of East China. Approximately 360 calves died due to watery diarrhea despite antibiotic therapy. In this study, 18 fecal specimens were collected from seriously ill calves on this farm during the diarrhea outbreak, and analysed for common enteropathogens by enzymatic immunoassay (EIA). In a post-outbreak investigation, 418 and 1372 specimens collected from animals of various age groups were further analysed for rotavirus and Cryptosporidium spp. by EIA and PCR, respectively, to assess their roles in the occurrence of diarrhea on the farm. Cryptosporidium spp. were genotyped using established techniques. Initial EIA tests showed that 15/18 seriously ill calves during the outbreak were positive for Cryptosporidium parvum, while 8/18 were positive for rotavirus. The overall infection rate of Cryptosporidium in pre-weaned calves on the farm was 22.7%, with odds of the Cryptosporidium infection during the outbreak 4.4–23.5 times higher than after the outbreak. Four Cryptosporidium spp. were identified after the outbreak including C. parvum (n = 79), Cryptosporidium ryanae (n = 48), Cryptosporidium bovis (n = 31), and Cryptosporidium andersoni (n = 3), with co-infections of multiple species being detected in 34 animals. Infection with C. parvum (73/79) was found in the majority of calves aged ≤3 weeks, consistent with the age of ill calves during the outbreak. All C. parvum isolates were identified as subtype IIdA19G1. In the post-outbreak investigation, C. parvum infection was associated with the occurrence of watery diarrhea in pre-weaned calves, C. ryanae infection was associated with moderate diarrhea in both pre- and post-weaned calves, while no association was identified between rotavirus infection and the occurrence of diarrhea. Results of logistic regression analysis further suggested that C. bovis infection might also be a risk factor for moderate diarrhea in calves. Thus, we believe this is the first report of a major outbreak of severe diarrhea caused by C. parvum IIdA19G1 in dairy calves. More attention should be directed toward preventing the dissemination of this virulent subtype in China.

Long-term use of yeast fermentation products in comparison to halofuginone for the control of cryptosporidiosis in neonatal calves

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Prophylactic effect of halofuginone against bovine cryptosporidiosis is equivocal.

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Saccharomyces cerevisiae fermentation products (SCFP) are feed additives.

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SCFP feeding showed similar clinical effects in newborn calves as halofuginone.

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Pre-weaning supplementation with SCFP may be an alternative in bovine cryptosporidiosis.

The objective of this study was to compare the effect of non-GMO Saccharomyces cerevisiae fermentation products (SCFP) with that of a halofuginone treatment against Cryptosporidium parvum infection in pre-weaned calves on a commercial dairy farm. A total of 123 neonatal female calves, housed in individual hutches, were enrolled sequentially based on date of birth in 41 blocks of 3 animals each. Calves within each block were allocated to one of 3 treatments: remaining untreated, fed with SCFP (Diamond V SmartCare^® at 1 g/d in milk and NutriTek^® at 5 g/d in starter grain) for the first 63 days of life, or treated with halofuginone (0.1 mg/kg/d) for the first 7 days of life. Fecal samples collected on days 4–21 post-partum were examined for both Cryptosporidium oocysts and coproantigen. The presence and intensity of diarrhea were monitored by scoring daily for the first 4 weeks of life. Calves were weighed at 0, 21, 42 and 63 days of age. Almost all calves were Cryptosporidium-positive at least once during the study. Halofuginone significantly reduced the number of Cryptosporidium-positive fecal samples as compared to the two other groups. Based on the coproantigen scores, both halofuginone and SCFP feeding significantly reduced the intensity of Cryptosporidium infection as compared to the untreated group. Diarrhea was recorded in almost all calves at least once. Neither the proportion of diarrheic calves nor the intensity and duration of diarrhea differed among the 3 treatment groups significantly. The mean daily weight gain during the first 3 weeks of life was significantly lower in halofuginone treated calves than in both other groups; however, at the end of the study period the total weight gain did not significantly differ among the 3 treatment groups. In conclusion, the clinical results and weight gains of pre-weaning supplementation with the SCFP were neither better nor worse than the 7-day halofuginone treatment suggesting that the SCFP feeding may be from the clinical point of view a natural alternative measure, instead of halofuginone treatment, in bovine cryptosporidiosis.

Molecular epidemiology of Cryptosporidium spp. in calves in Estonia: high prevalence of Cryptosporidium parvum shedding and 10 subtypes identified

We investigated the molecular epidemiology of Cryptosporidium spp. in Estonia by testing fecal samples from 486 calves aged <2 months, raised on 53 cattle farms, for the presence of Cryptosporidium DNA. The parasites were identified and characterized by sequencing of the 18S rRNA gene and of the 60 kDa glycoprotein (gp60) gene. Moreover, using a questionnaire, we surveyed factors that could be relevant for animal-to-human and human-to-animal transmission of Cryptosporidium spp. on the farms. Cryptosporidium spp. were shed by 23% of the investigated calves and at least one shedding calf was found on 66% of the farms. Cryptosporidium parvum was the most common species shed, while C. bovis and C. ryanae were also detected. More than half of the calves aged 8-14 days shed C. parvum. Nine previously described C. parvum subtypes (IIaA14G1R1, IIaA16G1R1, IIaA17G1R1, IIaA18G1R1, IIaA19G1R1, IIaA20G1R1, IIaA21G1R1, IIaA22G1R1 and IIaA16G2R1) and an apparently novel subtype IIlA21R2 were found. Calves from farms that reported spreading manure on fields during spring had 10 times higher odds to shed Cryptosporidium spp. in their feces than calves from farms that did not. Calves aged 8-14 days had higher odds to shed IIa18G1R1 as well as IIaA16G1R1 than younger calves.