Cryptosporidium and Giardia associated with reduced lamb carcase productivity

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.

Molecular evaluation of Cryptosporidium spp. in sheep in southern Xinjiang, China

Cryptosporidium spp. are diarrheagenic intestinal parasites with multiple hosts worldwide. A total of 1252 fresh fecal samples of sheep were collected from 10 large-scale farms in southern Xinjiang. Based on the small subunit ribosomal (SSU rRNA) gene of Cryptosporidium, 100 Cryptosporidium-positive samples (8.0%, 100/1252) were detected by PCR. Nine out of 10 farms were positive for Cryptosporidium, with the highest infection rate being 18.4% (23/125) on farm 9 in Qira. The infection rates of Cryptosporidium in pre-weaned lambs, weaned lambs, fattening sheep, and adult sheep were 20.3% (61/301), 10.3% (34/329), 0.9% (3/327), and 0.7% (2/295), respectively. Three Cryptosporidium species were identified, namely, C. xiaoi (n = 61), C. parvum (n = 22), and C. ubiquitum (n = 17). Of them, C. xiaoi was detected on all positive farms and in different age groups of sheep. The subtypes of C. parvum and C. ubiquitum were identified by PCR at the 60 kDa glycoprotein (gp60) gene. Two C. parvum subtypes were identified: IIdA19G1 (n = 21) and IIdA15G1 (n = 1). One C. ubiquitum subtype was identified with XIIa (n = 17). These results indicated the common transmission and genetic diversity of Cryptosporidium in sheep in southern Xinjiang, and further investigations are needed on the zoonotic potential of C. parvum and C. ubiquitum in this region.

Molecular characterizations of Giardia duodenalis based on multilocus genotyping in sheep, goats, and beef cattle in Southwest Inner Mongolia, China

Giardia duodenalis is an important zoonotic parasite that causes economic losses to animal husbandry and threatens public health. In the present study, a total of 1466 fresh fecal samples were collected from sheep (n = 797), goats (n = 561) and beef cattle (n = 108) in Southwest Inner Mongolia, China. Giardia duodenalis was initially screened via nested polymerase chain reaction (PCR) targeting the β-giardin (bg) gene, and bg-positive samples were subjected to PCR amplification targeting the glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) genes. A total of 4.0% of samples (58/1466) were positive for G. duodenalis, with a prevalence of 3.4% in sheep, 3.7% in goats and 5.2% in beef cattle. Three G. duodenalis assemblages (A, B, and E) were identified, with E as the prevalent assemblage. Four and one novel assemblage E sequences were obtained for the gdh and tpi loci, respectively and four assemblage E multilocus genotypes (MLG) were obtained. This study demonstrates high genetic variations in G. duodenalis assemblage E, and provides baseline data for preventing and controlling G. duodenalis infection in livestock in Inner Mongolia.

Literature Review: Coinfection in Young Ruminant Livestock-Cryptosporidium spp. and Its Companions

The protozoan Cryptosporidium parvum is one of the major causative pathogens of diarrhoea in young ruminants; therefore, it causes economic losses and impairs animal welfare. Besides C. parvum, there are many other non-infectious and infectious factors, such as rotavirus, Escherichia coli, and Giardia duodenalis, which may lead to diarrhoeic disease in young livestock. Often, more than one infectious agent is detected in affected animals. Little is known about the interactions bet-ween simultaneously occurring pathogens and their potential effects on the course of disease. In this review, a brief overview about pathogens associated with diarrhoea in young ruminants is presented. Furthermore, information about coinfections involving Cryptosporidium is provided.

Zoonotic pathogens in wild muskoxen (Ovibos moschatus) and domestic sheep (Ovis aries) from Greenland

The present study aimed to estimate the prevalence of zoonotic pathogens Giardia duodenalis, Cryptosporidium spp., Toxoplasma gondii and Erysipelothrix in muskoxen (Ovibos moschatus) and sheep (Ovis aries) from Greenland. In 2017 and 2018, faecal samples were collected from wild muskoxen from three distinct populations (Zackenberg, Kangerlussuaq, and Ivittuut) and from domestic sheep from southwest Greenland. Blood samples were collected from muskoxen from Kangerlussuaq and Ivittuut and from sheep. Faecal samples were tested for specific DNA of G. duodenalis and Cryptosporidium spp., and blood samples were tested for antibodies against T. gondii and Erysipelothrix. The estimated prevalence of G. duodenalis was 0% (0/58), 17% (7/41) and 0% (0/55) in muskoxen from Zackenberg, Kangerlussuaq and Ivittuut, respectively, and 37% (16/43) in sheep. The estimated prevalence of Cryptosporidium was 0% (0/58), 2% (1/41), 7% (4/55) in muskoxen from Zackenberg, Kangerlussuaq, Ivittuut, respectively, and 2% (1/43) in sheep. Neither Giardia nor Cryptosporidium were detected in winter samples (0/78). Of the positive samples, Giardia from one muskox sample only was successfully typed as G. duodenalis assemblage A, and Cryptosporidium from two muskoxen was successfully typed as C. parvum, subtype IIdA20G1e. The estimated T. gondii seroprevalence was 2% (1/44) and 0% (0/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 1% (1/155) in sheep. The estimated Erysipelothrix seroprevalence was 2% (1/45) and 13% (1/8) in muskoxen from Kangerlussuaq and Ivittuut, respectively, and 7% (10/150) in sheep. The results of this study add to the scarce knowledge on zoonotic pathogens in the Arctic.

Cryptosporidium and Giardia in dam water on sheep farms - An important source of transmission?

Cryptosporidium and Giardia infections can negatively impact livestock health and reduce productivity, and some species and genotypes infecting livestock have zoonotic potential. Infection occurs via the faecal-oral route. Waterborne infections are a recognised source of infection for humans, but the role of livestock drinking water as a source of infection in livestock has not been described. This study aimed to determine whether contaminated drinking water supplies, such as farm dams, are a likely transmission source for Cryptosporidium and Giardia infections for extensively managed sheep. Dam water samples (n = 47) were collected during autumn, winter and spring from 12 farm dams located on six different farms in south west Western Australia, and faecal samples (n = 349) were collected from sheep with access to these dams. All samples were initially screened for Cryptosporidium spp. at the 18S locus and Giardia spp. at the gdh gene using qPCR, and oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR. Cryptosporidium-positive sheep faecal samples were typed and subtyped by sequence analysis of 18S and gp60 loci, respectively. Giardia-specific PCR and Sanger sequencing targeting tpi and gdh loci were performed on Giardia- positive sheep faecal samples to characterise Giardia duodenalis assemblages. To identify Cryptosporidium and Giardia spp. in dam water samples, next-generation sequencing analysis of 18S and gdh amplicons were performed, respectively. Two species of Cryptosporidium (Cryptosporidium xiaoi and Cryptospordium ubiquitum (subtype family XIIa)) were detected in 38/345 sheep faecal samples, and in water from 9/12 farm dams during the study period, with C. xiaoi the species most frequently detected in both faeces and dam water overall. Giardia duodenalis assemblages AI, AII and E were detected in 36/348 faecal samples and water from 10/12 farm dams. For dam water samples where oo/cysts were detected by qPCR, Cryptosporidium oocyst concentration ranged from 518-2429 oocysts/L (n = 14), and Giardia cyst concentration ranged from 102 to 1077 cysts/L (n = 17). Cryptosporidium and Giardia with zoonotic potential were detected in farm dam water, including C. ubiquitum, C. hominis, C. parvum, C. cuniculus, C. xiaoi, and G. duodenalis assemblages A, B and E. The findings suggest that dam water can be contaminated with Cryptosporidium species and G. duodenalis assemblages that may infect sheep and with zoonotic potential, and farm dam water may represent one source of transmission for infections.

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.

Diarrhoea associated with gastrointestinal parasites in grazing sheep

Diarrhoea is a common, widespread and frustrating reality for sheep enterprises in most sheep producing regions globally and of particular concern in Australia as the major risk factor for breech flystrike. Parasitic disease has long been recognised as an important factor in diarrhoea in sheep, particularly the gastrointestinal nematodes (Trichostrongylus and Teladorsagia species). This review focuses on the role of parasitic infections in causing diarrhoea in sheep, with emphasis on the epidemiology of diarrhoea outbreaks related to worms and opportunities to manage the risk of diarrhoea outbreaks in sheep related to parasitic infections. Parasitic nematodes damage the gastrointestinal tract via a complex relationship between direct impacts from worms, such as physical changes to the gut mucosa, and indirect effects largely associated with the host response. Diarrhoea associated with large worm burdens is most efficiently managed through integrated parasite management programs. Despite some limitations, measuring faecal worm egg counts remains a mainstay for assessing the contribution of worms to outbreaks of diarrhoea in sheep. Larval hypersensitivity scouring is emerging as a significant cause of worm-related diarrhoea in sheep without large adult worm burdens in some geographic locations. The syndrome describes a heightened inflammatory response to the ingestion of trichostrongylid infective larvae seen in the gut of sheep with diarrhoea, and is most effectively addressed through selecting sheep for low breech soiling ('dag scores'), as worm resistant sheep may show an increased propensity for diarrhoea, even with low rates of larval challenge. Importantly, dag should be considered as a separate trait to WEC in breeding indexes. Outbreaks of diarrhoea in young sheep are often multifactorial, and co-infections with nematodes and other infectious agents associated with diarrhoea are common. This presents challenges for the field investigation of diarrhoea in grazing sheep.

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.

Long-term production effects of clinical cryptosporidiosis in neonatal calves

•

Cryptosporidium parvum is a major cause of enteric disease in neonatal calves.

•

Clinically severe cryptosporidiosis in neonatal calves significantly reduces weight gain.

•

The impact of reduced weight gain in calves is seen over a 6 month period.

Cryptosporidiosis can have a devastating effect in neonatal calves, resulting in diarrhoea, dehydration and, in severe cases, death of the animal. The disease is caused by Cryptosporidium spp. and is one of the most common causes of calf enteritis in the UK. The parasite is very difficult to remove from the farm, as the oocysts have a tough outer wall which enables the parasite to survive for several months in moist temperate environmental conditions and it is difficult to kill oocysts with common disinfectants used on a farm. If appropriate management practises are applied, the disease is usually self-limiting and most calves will recover. It has been shown, in studies with children and in lambs, that severe clinical cryptosporidiosis can result in long-term growth and cognitive impairment compared with individuals with no obvious signs of the disease. This study measured the long-term growth rate of beef calves on farm by comparing groups of animals that had suffered differing degrees of clinical severity of cryptosporidiosis as neonates. A group of 27 beef calves were enrolled in the study and monitored from birth to 6 months of age. The calves were scored for severity of cryptosporidiosis and weighed at regular intervals. The average difference in weight gain, at 6 months, between a group of calves that had severe cryptosporidiosis as neonates and a group of calves with no clinical signs of infection was 34 kg. Those calves that had experienced severe cryptosporidiosis as neonates showed a significantly reduced live weight gain compared with those calves showing no clinical signs of infection (P = 0.034). Therefore, the impact of severe cryptosporidiosis in neonatal calves has longer term effects on weight gain and production efficiency, resulting in the parasite having a greater impact on cattle production than previously thought.

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.

Molecular epidemiology of giardiasis from a veterinary perspective

A total of eight Giardia species are accepted. These include: Giardia duodenalis (syn. Giardia intestinalis and Giardia lamblia), which infects humans and animals, Giardia agilis, Giardia ardeae, Giardia psittaci, Giardia muris, Giardia microti, Giardia peramelis and G. cricetidarum, which infect non-human hosts including amphibians, birds, rodents and marsupials. Giardia duodenalis is a species complex consisting of eight assemblages (A-H), with assemblages A and B the dominant assemblages in humans. Molecular studies to date on the zoonotic potential of Giardia in animals are problematic and are hampered by lack of concordance between loci. Livestock (cattle, sheep, goats and pigs) are predominantly infected with G. duodenalis assemblage E, which has recently been shown to be zoonotic, followed by assemblage A. In cats and dogs, assemblages A, B, C, D and F are commonly reported but relatively few studies have conducted molecular typing of humans and their pets and the results are contradictory with some studies support zoonotic transmission but the majority of studies suggesting separate transmission cycles. Giardia also infects a broad range of wildlife hosts and although much less well studied, host-adapted species as well as G. duodenalis assemblages (A-H) have been identified. Fish and other aquatic wildlife represent a source of infection for humans with Giardia via water contamination and/or consumption of undercooked fish and interestingly, assemblage B and A predominated in the two molecular studies conducted to date. Our current knowledge of the transmission dynamics of Giardia is still poor and the development of more discriminatory typing tools such as whole genome sequencing (WGS) of Giardia isolates is therefore essential.

Shedding of Cryptosporidium in calves and dams: evidence of re-infection and shedding of different gp60 subtypes

One of the most common causes of calf diarrhoea is the parasite Cryptosporidium parvum. Two longitudinal studies were carried out on a dairy farm Scotland to determine the prevalence of Cryptosporidium species and subtypes in a group of calves and to determine whether dams were a possible source of calfhood infection. Fecal samples were collected from 25 calves from birth to 12 months in the first year. In the second year, fecal samples were collected from pregnant cows (n = 29) and their calves (n = 30) from birth to 6 months. The samples were tested for Cryptosporidium and speciated. Cryptosporidium parvum-positive samples were subtyped by GP60 fragment analysis. All calves in both studies shed Cryptosporidium during the study period. Cryptosporidium parvum was the predominant species detected in calves ⩽6 weeks of age and at 6 months of age, C. bovis and C. ryanae were detected in calves older than 4 weeks of age but ⩽6 months of age. The prevalence of Cryptosporidium was higher in younger animals than in older animals. GP60 subtyping revealed two subtypes in calves on this farm (IIaA15G2R1 and IIaA19G2R1) that differed in frequency by age. Adult cattle also shed C. parvum, of four gp60 genotypes.

Multi-locus genotyping and phylogenetic analyses of Giardia intestinalis isolates from indigenous goats in Ogun State, Nigeria

Giardiasis is a common gastrointestinal disease of humans and various animal species worldwide. In this study, 302 stool samples were collected from West African Dwarf and Sokoto Red breeds of goats in Ogun State, Nigeria, and screened for Giardia intestinalis coproantigens using enzyme-linked immunosorbent assay (ELISA). The genotypes of G. intestinalis in faecal samples collected from 152 goats raised on selected farms were identified by polymerase chain reaction (PCR) amplification and sequence analyses of the small subunit ribosomal RNA (ssu rRNA), glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi) and β-giardin (bg) genes. Based on ELISA, an overall prevalence of 45.7% was recorded with the infection rates in pre-weaned (60.2%) and post-weaned goat kids (51.5%) being significantly (p < 0.05) higher than in adults (28.2%). Giardia intestinalis DNA was amplified in 31.6% and 29.6% of goat faeces at the ssu rRNA and gdh loci respectively. These were genotyped at the ssu rRNA locus as assemblages B (n = 13) and E (n = 36). Similar results were observed at the gdh locus except that eight isolates contained assemblage E mixed with either assemblage A or B. Additionally, sub-assemblages BI (n = 7) and BIII (n = 2) were identified with up to four single nucleotide polymorphisms (SNPs) occurring in these isolates. Multilocus genotypes (MLG) of all assemblage E isolates were identified using the ssu rRNA and gdh loci while MLG of all isolates containing assemblage B and mixed assemblages were determined after further typing at the tpi and bg loci. Forty-two MLG isolates were identified and these comprised 32, 8 and 2 (sub)-assemblage E, BI and BIII respectively. All isolates with mixed assemblages at the gdh locus were consequently designated as assemblage E by MLG. The assemblage E isolates from goats were genetically related to isolates from cattle, sheep and goats while the assemblage B isolates were related to isolates of human, pig and lemur origin. This suggests that G. intestinalis isolated from goats bred in Ogun State, Nigeria may be capable of cross-species transmission and may be of zoonotic importance.

Acute phase response in organic lambs associated with colostrum serum amyloid A, weight gain, and Cryptosporidium and Giardia infections

In neonatal period, lamb's immune system goes through rapid adaptation to the extra-uterine environment. Success of this process can influence the animal's future performance and, thus, the quantitative assessment of it would greatly benefit sheep producers. The current study was conducted to investigate the acute phase response (APR) (measured through serum amyloid A (SAA), haptoglobin (Hp) and albumin (ALB)) in relation to later life growth (measured at 122 days of age), and naturally occurring Cryptosporidium and Giardia infections in neonatal lambs grown in organic farm. Serum (n = 692) and faecal (n = 141) samples were collected from 269 lambs in their first 3 weeks of life. The ewes' colostrum (n = 181) SAA concentrations were positively associated with the lambs' serum SAA and Hp concentrations at 2 to 4 days of age. Hp and ALB concentrations at the second week of age were positively associated with the growth rate at 122 days of age. Lamb serum globulin (GLOB) concentrations and Cryptosporidium-positive faecal samples were negatively associated at the second and third weeks of life. These findings suggest the importance of interactions between the immune system and environmental factors at the second week of the lambs' lives and its association with future performance.

Cryptosporidium infection is associated with reduced growth and diarrhoea in goats beyond weaning

Cryptosporidium and Giardia are common parasites of ruminant livestock worldwide. These parasites are associated with diarrhoea outbreaks in young goats (pre-weaning), but the impacts on health and productivity for older goats (post-weaning) are not well understood. Here we show Cryptosporidium faecal shedding is associated with reduced growth and diarrhoea in goats aged approximately 9-15 months. Goats were sampled four times at one-month intervals. Faecal shedding for a range of pathogens were determined using quantitative PCR and sequencing (Cryptosporidium, Giardia, Eimeria, Salmonella, Campylobacter), and microscopy (trichostrongylid nematode worm egg count and Entamoeba). Cryptosporidium faecal shedding was associated with 1.5 kg lower growth for the one-month period following sampling. Specifically, C. xiaoi was associated with 1.9 kg lower growth in the following month. This is the first report of production impacts associated with C. xiaoi in ruminants older than 3 months of age. Cryptosporidium shedding was associated with an over 4-fold increase in risk of diarrhoea, with C. parvum associated with 10-fold and C. ubiquitum associated with 16-fold increase in risk of diarrhoea. Notably, C. xiaoi shedding was not associated with increased risk of diarrhoea. Giardia shedding was associated with looser faecal consistency, but not diarrhoea. Higher Eimeria oocyst counts were weakly associated with lower live weight, poorer body condition and looser faecal consistency. Shedding of other enteric pathogens were not associated with impacts on live weight, growth or diarrhoea risk. This study challenges the two notions that Cryptosporidium infections only impact health and productivity of goats during the pre-weaning period, and that Cryptosporidium (and specifically C. xiaoi) infections in the absence of diarrhoea are asymptomatic. Recognising the potential for impacts of Cryptosporidium infection on growth rates in the absence of diarrhoea will support improved design for experiments testing impacts of Cryptosporidium on ruminant health and production. Improved understanding of the role of protozoan infections on animal health has implications for the management of goats in order to reduce adverse impacts on farm profitability, animal welfare and public health risk.

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.

Global Cryptosporidium Loads from Livestock Manure

Understanding the environmental pathways of Cryptosporidium is essential for effective management of human and animal cryptosporidiosis. In this paper we aim to quantify livestock Cryptosporidium spp. loads to land on a global scale using spatially explicit process-based modeling, and to explore the effect of manure storage and treatment on oocyst loads using scenario analysis. Our model GloWPa-Crypto L1 calculates a total global Cryptosporidium spp. load from livestock manure of 3.2 × 10²³ oocysts per year. Cattle, especially calves, are the largest contributors, followed by chickens and pigs. Spatial differences are linked to animal spatial distributions. North America, Europe, and Oceania together account for nearly a quarter of the total oocyst load, meaning that the developing world accounts for the largest share. GloWPa-Crypto L1 is most sensitive to oocyst excretion rates, due to large variation reported in literature. We compared the current situation to four alternative management scenarios. We find that although manure storage halves oocyst loads, manure treatment, especially of cattle manure and particularly at elevated temperatures, has a larger load reduction potential than manure storage (up to 4.6 log units). Regions with high reduction potential include India, Bangladesh, western Europe, China, several countries in Africa, and New Zealand.

Prevalence and risk factors for cryptosporidiosis: a global, emerging, neglected zoonosis

Background

Cryptosporidiosis is a zoonotic disease caused by the important parasitic diarrheal agent Cryptosporidium spp. Cryptosporidiosis occurs in all classes of animals and man with a rapidly expanding host range and increased importance since the occurrence of human immunodeficiency virus/acquired immunodeficiency syndrome in man.

Objectives

To review the global picture of cryptosporidiosis in man and animals with emphasis on prevalence and risk factors.

Methods

Current relevant literature on cryptosporidiosis was reviewed.

Results

Cryptosporidiosis is widely distributed and the risk factors vary from one region to another with hygiene and immune status as important risk factors.

Conclusions

Cryptosporidium spp. associated mortality has not only been reported in immune-compromised patients, but also in immune-competent patients. Yet in many countries not much attention is paid to the control and prevention of this infection in animals and man. The neglect of this disease despite the serious threat it poses to animals, their husbandry, and humans, has led the World Health Organization to list it among globally neglected diseases. To control and prevent this infection more effort needs to be directed at controlling the risk factors of the infection in man and animals.

Zoonotic Cryptosporidium and Giardia shedding by captured rangeland goats

Faecal shedding of Cryptosporidium and Giardia by captured rangeland goats was investigated using a longitudinal study with four faecal samples collected from 125 male goats once monthly for four months, commencing immediately after capture and transport to a commercial goat depot (feedlot). Goats were composite breed and aged approximately 9-12months on arrival. Faecal samples were screened for Cryptosporidium and Giardia presence and concentration using quantitative PCR and sequencing at the 18S ribosomal RNA locus (Cryptosporidium), and glutamate dehydrogenase and β-giardin loci (Giardia). Longitudinal prevalence for Cryptosporidium was 27.2% (point prevalence range 3-14%) with 3 species identified: C. xiaoi (longitudinal prevalence 13.6%), C. ubiquitum (6.4%) and C. parvum (3.2%). Sub-typing at the gp60 locus identified C. ubiquitum XIIa, C. parvum IIaA17G2R1 and C. parvum IIaA17G4R1. This is the first report of the zoonotic C. parvum subtype IIaA17G4R1 in goats. The pattern of genotypes shed in faeces changed over the duration of study with C. ubiquitum identified only at the first and second samplings, and C. parvum identified only at the fourth sampling. Longitudinal prevalence for Giardia duodenalis was 29.6% (point prevalence range 4-12%) with all positives sub-typed as assemblage E. Only 2/125 goats were identified to be shedding Cryptosporidium or Giardia on more than one occasion. This is the first report of Cryptosporidium and Giardia genotypes in captured rangeland goats. Faecal shedding of zoonotic Cryptosporidium spp. and potentially zoonotic G.duodenalis has implications for food safety and effluent management. Keywords: Cryptosporidium; Giardia; Rangeland goats; zoonotic.

Cryptosporidium and Giardia in Danish organic pig farms: Seasonal and age-related variation in prevalence, infection intensity and species/genotypes

Although pigs are commonly infected with Cryptosporidium spp. and Giardia duodenalis, including potentially zoonotic species or genotypes, little is known about age-related infection levels, seasonal differences and genetic variation in naturally infected pigs raised in organic management systems. Therefore, the current study was conducted to assess seasonal and age-related variations in prevalence and infection intensity of Cryptosporidium and Giardia, evaluate zoonotic potential and uncover correlations between species/genotypes, infection intensity and faecal consistency. Shedding of oocysts and cysts ((oo-)cysts) was monitored at quarterly intervals (September 2011-June 2012) in piglets (n = 152), starter pigs (n = 234), fatteners (n = 230) and sows (n = 240) from three organic farms in Denmark. (oo-)Cysts were quantified by immunofluorescence microscopy; and 56/75 subsamples from Cryptosporidium infected pigs were successfully analysed by PCR amplification and partial sequencing of the small subunit (SSU) 18S rRNA and hsp70genes, while 13/67 Giardia subsamples were successfully analysed by amplification and partial sequencing of the 18S rRNA and the gdh genes. Altogether, Cryptosporidium or Giardia infections were observed in 40.9% (350/856) and 14.0% (120/856) of the pigs, respectively, including 8.2% (70/856) infected with both parasites. Prevalence, intensity of infections and presence of Cryptosporidium species varied significantly between age-groups; 53.3% piglets, 72.2% starter pigs, 40.4% fatteners and 2.9% sows were infected with Cryptosporidium, whereas 2.0% piglets, 27.4% starter pigs, 17.8% fatteners and 5.0% sows were infected with Giardia. The overall prevalence was stable throughout the year, except for dual-infections that were more prevalent in September and December (p < 0.05). The infection intensity was age-related for both parasites, and dual-infected pigs tended to excrete lower levels of oocysts compared to pigs harbouring only Cryptosporidium. Likewise, pigs infected with Cryptosporidium scrofarum excreted fewer oocysts (mean CPG: 54,848 ± 194,508CI: 9085-118,781) compared to pigs infected with Cryptosporidium suis (mean OPG: 351,035 ± 351,035CI: 67,953-634,117). No correlation between faecal consistency and (oo-)cyst excretion levels was observed. Of the successfully genotyped isolates, 38/56 (67.9%) were C. scrofarum and 18/56 (32.1%) were C. suis, while the livestock specific G. duodenalis Assemblage E was detected in 11/13 (84.6%) isolates and the potentially zoonotic Assemblage A was identified in 2/13 (15.4%) isolates. Piglets exclusively hosted C. suis, with one exception, while starter pigs and fatteners predominantly hosted C. scrofarum. As organic pigs are partly reared outdoors, environmental contamination with Cryptosporidium and Giardia is inevitable. Nevertheless, the present data indicate that the potential public health risk associated with both of these parasites in Danish organic pig production seems to be negligible.

Zoonoses parasitárias veiculadas por alimentos de origem animal: revisão sobre a situação no Brasil

O Brasil se destaca na produção mundial de alimentos de origem animal, sendo que cada vez mais os mercados consumidores buscam alimentos seguros e inócuos para a saúde. Nesse contexto, torna-se fundamental a prevenção das zoonoses, que podem ser transmitidas através dos alimentos de origem animal, que muitas vezes são consumidos sem o devido preparo ou por populações mais vulneráveis. Nesta revisão bibliográfica, serão abordadas importantes enfermidades parasitárias de caráter zoonótico que ocorrem atualmente pela via de transmissão alimentar: a toxoplasmose, o complexo teníase-cisticercose, criptosporidiose, anisacose, difilobotriose e triquinelose.

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.

Genetic characterizations of Giardia duodenalis in sheep and goats in Heilongjiang Province, China and possibility of zoonotic transmission

Background

Giardia duodenalis is a widespread intestinal protozoan of both humans and mammals. To date, few epidemiological studies have assessed the potential and importance of zoonotic transmission; and the human giardiasis burden attributable to G. duodenalis of animal origin is unclear. No information about occurrence and genotyping data of sheep and goat giardiasis is available in China. The aim of the present study was to determine prevalence and distribution of G. duodenalis in sheep and goats in Heilongjiang Province, China, and to characterize G. duodenalis isolates and assess the possibility of zoonotic transmission.

Methodology/Principal Findings

A total of 678 fecal specimens were collected from sheep and goats on six farms ranging in age from one month to four years in Heilongjiang Province, China. The average prevalence of G. duodenalis infection was 5.0% (34/678) by microscopy after Lugol's iodine staining, with 5.6% (30/539) for the sheep versus 2.9% (4/139) for the goats. Molecular analysis was conducted on 34 G. duodenalis isolates based on the triosephosphate isomerase (tpi) gene. 29 tpi gene sequences were successfully obtained and identified as assemblages A (n = 4), B (n = 2) and E (n = 23). High heterogeneity was observed within assemblage E at the tpi locus, with five novel subtypes found out of seven subtypes. Two subtypes of assemblage A were detected, including subtype AI (n = 3) and a novel subtype (designated as subtype AIV) (n = 1). Two assemblage B isolates were identical to each other in the tpi gene sequences.

Conclusions/Significance

This is the first report of G. duodenalis infections in sheep and goats in China. The present data revealed the unique endemicity on prevalence, distribution and genetic characterization of G. duodenalis in sheep and goats in Heilongjiang Province. The findings of assemblages A and B in sheep and goats implied the potential of zoonotic transmission.

Giardiasis is a kind of zoonotic disease with global distribution. Due to the great number of asymptomatic giardiasis cases, human giardiasis is often underreported. The sources of infection of giardiasis are feces of humans and mammals with the pathogen being transmitted by the fecal-oral route. In this study, we described the occurrence of sheep and goat giardiasis and genetic charaterizations of G. duodenalis isolates in Heilongjiang Province, China. The average infection rate was 5.0% (34/678), with 5.6% (30/539) for the sheep versus 2.9% (4/139) for the goats. G. duodenalis assemblages and subtypes were genetically diagnosed by sequence analysis. Three assemblages were successfully identified out of 29 tpi gene sequences, with the percentages 13.8% (4/29), 6.9% (2/29), 79.3% (23/29) for assemblages A, B and E, respectively. Five novel subtypes were found out of seven subtypes of assemblage E. Two subtypes of assemblage A were detected, with one belonging to a novel subtype and the other belonging to assemblage AI. Two assemblage B isolates were identical to each other at the tpi locus. Prevalence, distribution and genetic characteristics of subtypes of G. duodenalis in sheep and goats appear to be unique in the areas examined. The sheep and goats infected with assemblages A and B have important public heath significance.

Cryptosporidium species in Australian wildlife and domestic animals

Cryptosporidium is an important enteric parasite that is transmitted via the fecal-oral route, water and food. Humans, wildlife and domestic livestock all potentially contribute Cryptosporidium to surface waters. Most species of Cryptosporidium are morphologically indistinguishable and can only be identified using molecular tools. Over 24 species have been identified and of these, 7 Cryptosporidium species/genotypes are responsible for most human cryptosporidiosis cases. In Australia, relatively few genotyping studies have been conducted. Six Cryptosporidium species (C. hominis, C. parvum, C. meleagridis, C. fayeri, C. andersoni and C. bovis) have been identified in humans in Australia. However, little is known about the contribution of animal hosts to human pathogenic strains of Cryptosporidium in drinking water catchments. In this review, we focus on the available genotyping data for native, feral and domestic animals inhabiting drinking water catchments in Australia to provide an improved understanding of the public health implications and to identify key research gaps.

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.