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

Occurrence and factors associated with Cryptosporidium infection in livestock in three districts of Zambia

Cryptosporidium is one of the most important enteric diarrhoeal parasites that infect humans and animals worldwide. The current study investigated the occurrence and risk factors associated with Cryptosporidium infection in ruminants aged ≤6 months in Monze, Mumbwa, and Lusaka districts of Zambia. Faecal samples were collected from 328 calves, 190 lambs, and 245 goat kids and analysed for Cryptosporidium oocysts using modified Ziehl Neelsen staining. A closed structured questionnaire was used to obtain epidemiological characteristics and potential risk factors for Cryptosporidium infection. The overall occurrence of Cryptosporidium was 7.9% (60/763), while that in calves, lambs and goat kids was 14.5% (47/328), 5.3% (10/190), and 1.2% (3/245) respectively. Watery/pasty stool and sampling during the rainy season were independently associated with increased risk of infection. In calves, the odds of infection increased during the rainy season, while daily kraal cleaning reduced the infection risk. Lambs showed increased odds of infection with pasty/watery stool and male sex, whereas the wearing of protective clothing by handlers significantly reduced the risk. There were district variations in infection occurrence with Mumbwa district having higher prevalence. The findings of this study show that livestock in Zambia continue to be frequently infected with Cryptosporidium. Protective measures and appropriate farm cleanliness should be implemented in control of this infection. Regional and host-species-specific variations emphasize the need for targeted interventions. These findings, therefore, contribute to effective strategies for Cryptosporidium control, promoting good livestock health and management.

Cryptosporidium spp. Infection and Genotype Identification in Pre-Weaned and Post-Weaned Calves in Yunnan Province, China

BACKGROUND

Cryptosporidium is a globally distributed zoonotic protozoan parasite in humans and animals. Infection is widespread in dairy cattle, especially in calves, resulting in neonatal enteritis, production losses and high mortality. However, the occurrence of Cryptosporidium spp. in pre- and post-weaned calves in Yunnan Province remains unclear.

METHODS

We collected 498 fecal samples from Holstein calves on 10 different farms in four regions of Yunnan Province. Nested PCR and DNA sequencing were used to determine the infection, species and genotypes of Cryptosporidium spp. in these animals.

RESULTS

The overall occurrence of Cryptosporidium spp. in Holstein calves was 32.9% (164/498), and the prevalence in pre- and post-weaned calves was 33.5% (106/316) and 31.9% (58/182), respectively. Four Cryptosporidium species were identified in these animals, namely C. bovis (n = 119), C. parvum (n = 23), C. ryanae (n = 20) and C. andersoni (n = 2). Based on sequencing analysis of the 60 kDa glycoprotein gene of C. bovis, C. parvum and C. ryanae, six subtypes of C. bovis (XXVIe, XXVIb, XXVIf, XXVIa XXVIc and XXVId), two subtypes of C. parvum (IIdA19G1 and IIdA18G1) and four subtypes of C. ryanae (XXIf, XXId, XXIe and XXIg) were identified.

CONCLUSIONS

These results provide essential information to understand the infection rate, species diversity and genetic structure of Cryptosporidium spp. populations in Holstein pre-weaned and post-weaned calves in Yunnan Province. Further, the presence of IIdA18G1 and IIdA19G1 in C. parvum implies significant animal and public health concerns, which requires greater attention and more preventive measures.

Epidemiological investigation of Cryptosporidium in children with diarrhea in middle Inner Mongolia, China

Cryptosporidia (Cryptosporidium) is a protozoan that is widely parasitic in the intestinal cells of humans and animals, and it is also an important zoonotic parasite. However, there is no epidemiological investigation on Cryptosporidium spp. infection in infants with diarrhea of Inner Mongolia, the largest livestock region in China. To investigate the prevalence of Cryptosporidium, 2435 fresh fecal samples were collected from children with diarrhea in Inner Mongolia Maternal and Child Health Care Hospital. Molecular characterization of Cryptosporidium was carried out based on its 18S rRNA and gp60 gene sequences. The overall prevalence was 12.85% (313/2435), and in Hohhot (12.15%), it was lower than that in the surrounding city (14.87%) (P < 0.05). Moreover, Cryptosporidium was detected in different seasons and sexes. Concerning the age of children with diarrhea, the prevalence of those age groups between 0 and 1 was obviously lower than others, and there were significant differences in the prevalence at different ages (P < 0.001). Analysis of the 18S rRNA gene sequence revealed that all the positive samples were Cryptosporidium parvum, and there were 5 subtypes (IIdA23G3, IIdA24G3, IIdA24G4, IIdA25G3, and IIdA25G4). To the best of our knowledge, the above subtypes have not been reported. Our results provide a relevant basis for control and education on food safety and foodborne illness prevention.

Human dendritic cell interactions with the zoonotic parasite Cryptosporidium parvum result in activation and maturation

Cryptosporidiosis in humans is caused by infection of the zoonotic apicomplexan parasite Cryptosporidium parvum. In 2006, it was included by the World Health Organization (WHO) in the group of the most neglected poverty-related diseases. It is characterized by enteritis accompanied by profuse catarrhalic diarrhea with high morbidity and mortality, especially in children of developing countries under the age of 5 years and in HIV patients. The vulnerability of HIV patients indicates that a robust adaptive immune response is required to successfully fight this parasite. Little is known, however, about the adaptive immune response against C. parvum. To have an insight into the early events of the adaptive immune response, we generated primary human dendritic cells (DCs) from monocytes of healthy blood donors and exposed them to C. parvum oocysts and sporozoites in vitro. DCs are equipped with numerous receptors that detect microbial molecules and alarm signals. If stimulation is strong enough, an essential maturation process turns DCs into unique activators of naïve T cells, a prerequisite of any adaptive immune response. Parasite exposure highly induced the production of the pro-inflammatory cytokines/chemokines interleukin (IL)-6 and IL-8 in DCs. Moreover, antigen-presenting molecules (HLA-DR and CD1a), maturation markers, and costimulatory molecules required for T-cell stimulation (CD83, CD40, and CD86) and adhesion molecules (CD11b and CD58) were all upregulated. In addition, parasite-exposed human DCs showed enhanced cell adherence, increased mobility, and a boosted but time-limited phagocytosis of C. parvum oocysts and sporozoites, representing other prerequisites for antigen presentation. Unlike several other microbial stimuli, C. parvum exposure rather led to increased oxidative consumption rates (OCRs) than extracellular acidification rates (ECARs) in DCs, indicating that different metabolic pathways were used to provide energy for DC activation. Taken together, C. parvum-exposed human DCs showed all hallmarks of successful maturation, enabling them to mount an effective adaptive immune response.

Prevalence and molecular characterization of Cryptosporidium spp., Enterocytozoon bieneusi, and Giardia duodenalis in dairy cattle in Ningxia, northwestern China

Cryptosporidium spp., Enterocytozoon bieneusi, and Giardia duodenalis are common intestinal pathogens that infect humans and animals. To date, research regarding these three protozoa in the Ningxia Hui Autonomous Region (Ningxia) has mostly been limited to a single pathogen, and comprehensive data on mixed infections are unavailable. This study aimed to evaluate the zoonotic potential of these three protozoa. In this study, small subunit ribosomal RNA (SSU rRNA) and 60 kDa glycoprotein (gp60) genes of Cryptosporidium; internal transcribed spacer (ITS) gene of E. bieneusi; and SSU rRNA, glutamate dehydrogenase (gdh), triosephosphate isomerase (tpi), and beta-giardin (bg) genes of G. duodenalis were examined. DNA extraction, polymerase chain reaction, and sequence analysis were performed on fecal samples collected from 320 dairy cattle at three intensive dairy farms in Ningxia in 2021 to determine the prevalence and genetic characteristics of these three protozoa. The findings revealed that 61.56% (197/320) of the samples were infected with at least one protozoan. The overall prevalence of Cryptosporidium was 19.38% (62/320), E. bieneusi was 41.56% (133/320), and G. duodenalis was 29.38% (94/320). This study identified four Cryptosporidium species (C. bovis, C. andersoni, C. ryanae, and C. parvum) and the presence of mixed infections with two or three Cryptosporidium species. C. bovis was the dominant species in this study, while the dominant C. parvum subtypes were IIdA15G1 and IIdA20G1. The genotypes of E. bieneusis were J, BEB4, and I alongside the novel genotypes NX1-NX8, all belonging to group 2, with genotype J being dominant. G. duodenalis assemblages were identified as assemblages E, A, and B, and a mixed infection involving assemblages A + E was identified, with assemblage E being the dominant one. Concurrently, 11 isolates formed 10 different assemblage E multilocus genotypes (MLGs) and 1 assemblage A MLG and assemblage E MLGs formed 5 subgroups. To the best of our knowledge, this is the first report on mixed infection with two or three Cryptosporidium species in cattle in Ningxia and on the presence of the C. parvum subtype IIdA20G1 in this part of China. This study also discovered nine genotypes of E. bieneusis and novel features of G. duodenalis assemblages in Ningxia. This study indicates that dairy cattle in this region may play a significant role in the zoonotic transmission of Cryptosporidium spp., E. bieneusi, and G. duodenalis.

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.

First Detection of Cryptosporidium parvum in the Endemic Cyprus Mouflon (Ovis gmelini ophion)

PURPOSE

Cryptosporidium is an intestinal zoonotic protozoan parasite that infects domesticated and wild animals. There are no reports on the prevalence and molecular characterisation of Cryptosporidium in the endemic Cyprus mouflon. The mouflon is strictly protected by national and international legislation. Its main distribution is Paphos State Forest and surrounding areas, where it may share the same water sources as free-ranging domestic goats. Therefore, the present study aimed to determine the prevalence of Cryptosporidium spp. and genotypes in mouflon and free-ranging goats within the mouflon range.

METHODS

Faecal samples of 70 mouflons and 34 free-ranging goats were screened for Cryptosporidium by PCR amplification and sequencing.

RESULTS

Only one sample (1/70) belonging to a mouflon was PCR positive for Cryptosporidium. Based on sequencing of the 18S rRNA locus, this species was identified as Cryptosporidium parvum (C. parvum). No positive sample was detected in the free-ranging goats (0/34).

CONCLUSION

This is the first report on the molecular identification of this Cryptosporidium species in a Cyprus mouflon. The results indicate that the prevalence of Cryptosporidium in Cyprus mouflon is low.

Development of a "Rapid-Crypto Colorimetric LAMP Test" to Detect Cryptosporidiosis in Feces of Newborns Calves

BACKGROUND

Cryptosporidiosis is a disease that causes major intestinal damage in humans and animals. The causative agents of the disease are Cryptosporidium species. In newborn calves, diarrhea can lead to death, resulting in significant economic losses for the farms. Therefore, accurate, rapid, and cost-effective diagnosis of the disease is very important.

MATERIAL AND METHODS

In this study, a novel colorimetric loop-mediated isothermal amplification (LAMP) test named "Rapid-Crypto Colorimetric LAMP test" targeting Cryptosporidium spp. 18S rRNA gene was developed to detect cryptosporidiosis in the feces of newborn calves. The analytical sensitivity of the test was determined by plasmid controls. Clinical sensitivity was determined using the feces of 127 calves collected from farms in İzmir and Manisa provinces. All of the samples were also investigated with Real-Time PCR targeting the Cryptosporidium spp. COWP gene. Cross-reactivity was tested using the DNA of other parasites and bacteria.

RESULTS

According to the results, the analytical sensitivity of the "Rapid-Crypto Colorimetric LAMP test" was found as 1 copy plasmid/reaction. When the results were compared with the Real-Time PCR test, the sensitivity of the "Rapid-Crypto Colorimetric LAMP test" was 100% and the specificity was 97.4%. The test did not cross-react with other parasites and bacteria.   CONCLUSION: The "Rapid-Crypto Colorimetric LAMP test" developed in this study provides an advantage in the diagnosis of Cryptosporidium spp. in calf stool samples since it can be applied in basic laboratories or in the field, does not require experienced personnel, and has high sensitivity. Moreover, diagnosis can be made with the naked eye without using any device.

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

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

Detection and Molecular Diversity of Cryptosporidium spp. and Giardia duodenalis in the Endangered Iberian Lynx (Lynx pardinus), Spain

Cryptosporidium spp. and Giardia duodenalis are the main non-viral causes of diarrhoea in humans and domestic animals globally. Comparatively, much less information is currently available in free-ranging carnivore species in general and in the endangered Iberian lynx (Lynx pardinus) in particular. Cryptosporidium spp. and G. duodenalis were investigated with molecular (PCR and Sanger sequencing) methods in individual faecal DNA samples of free-ranging and captive Iberian lynxes from the main population nuclei in Spain. Overall, Cryptosporidium spp. and G. duodenalis were detected in 2.4% (6/251) and 27.9% (70/251) of the animals examined, respectively. Positive animals to at least one of them were detected in each of the analysed population nuclei. The analysis of partial ssu rRNA gene sequences revealed the presence of rodent-adapted C. alticolis (n = 1) and C. occultus (n = 1), leporid-adapted C. cuniculus (n = 2), and zoonotic C. parvum (n = 2) within Cryptosporidium, and zoonotic assemblages A (n = 5) and B (n = 3) within G. duodenalis. Subgenotyping analyses allowed for the identification of genotype VaA19 in C. cuniculus (gp60 locus) and sub-assemblages AI and BIII/BIV in G. duodenalis (gdh, bg, and tpi loci). This study represents the first molecular description of Cryptosporidium spp. and G. duodenalis in the Iberian lynx in Spain. The presence of rodent/leporid-adapted Cryptosporidium species in the surveyed animals suggests spurious infections associated to the Iberian lynx's diet. The Iberian lynx seems a suitable host for zoonotic genetic variants of Cryptosporidium (C. parvum) and G. duodenalis (assemblages A and B), although the potential risk of human transmission is regarded as limited due to light parasite burdens and suspected low excretion of infective (oo)cysts to the environment by infected animals. More research should be conducted to ascertain the true impact of these protozoan parasites in the health status of the endangered Iberian lynx.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy and beef cattle in Shanxi, China

Cryptosporidium spp. are key gastrointestinal protists in humans and animals worldwide. Infected cattle are considered the main source of cryptosporidiosis outbreaks in humans. However, little is known about the genetic makeup of Cryptosporidium populations in Shanxi province, China. We analyzed 858 fecal samples collected from farms in Shanxi. The presence of Cryptosporidium spp. was determined via polymerase chain reaction and subsequent sequence analysis of the small subunit rRNA gene as well as restriction fragment length polymorphism analysis. Cryptosporidium parvum was subtyped following sequence analysis of the 60 kDa glycoprotein gene (gp60). The overall prevalence of Cryptosporidium in cattle was 11.19%, with a prevalence of 13.30% and 8.67% in Lingqiu and Yingxian, respectively. The overall prevalence of Cryptosporidium in dairy and beef cattle was 10.78% and 11.50%, respectively. Cryptosporidium infection was detected across all analyzed age groups. The overall prevalence of Cryptosporidium in diarrhea and nondiarrhea samples was 18.24% and 9.72%, respectively, whereas that in intensively farmed and free-range cattle was 17.40% and 3.41%, respectively. We identified five Cryptosporidium species, with C. andersoni being the dominant species. Further, two cases of mixed infections of Cryptosporidium species were detected. All identified C. parvum isolates belonged to the subtype IIdA17G1.

Prevalence of Cryptosporidium spp. infection in a working horse population in Egypt

Working horses support the livelihoods of smallholder farmers in Egypt. No previous study has investigated the prevalence of cryptosporidiosis in working horses in Egypt. Faecal samples were collected from 607 working horses recruited from thirty-seven villages/areas in two Egyptian governorates and examined for Cryptosporidium spp. infection using the modified Zielh-Neelsen staining technique. Data on signalment, history of recent diarrhoea, and strongyle burden were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for infection were investigated using mixed-effects logistic regression models that included sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5-33.9). None of the variables investigated, which include age, sex of the animals, and strongyle burden, were associated with risk of infection. This study provided evidence-based information on the prevalence of Cryptosporidium spp. infection in the study area. However, the potential zoonotic risk of Cryptosporidium cannot be confirmed until further studies are conducted to genotype these parasites.

Prevalence and molecular characterization of Cryptosporidium spp. in dairy cattle in Central Inner Mongolia, Northern China

BACKGROUND

Cryptosporidium is a gastrointestinal protozoan that widely exists in nature, it is an established zoonotic pathogen. Infected cattle are considered to be associated with cryptosporidiosis outbreaks in humans. In the present study, we aimed to assess the prevalence and species distribution of Cryptosporidium in dairy cattle in Central Inner Mongolia.

METHODS

We focused on the small subunit ribosomal RNA gene (SSU rRNA) of Cryptosporidium and 60-kDa glycoprotein gene (gp60) of Cryptosporidium parvum. We collected 505 dairy cattle manure samples from 6 sampling sites in Inner Mongolia in 2021; the samples were divided into 4 groups based on age. DNA extraction, polymerase chain reaction (PCR), sequence analysis, and restriction fragment length polymorphism (RFLP) using SspI and MboII restriction endonucleases were performed. RFLP analysis was performed to determine the prevalence and species distribution of Cryptosporidium.

RESULTS

SSU rRNA PCR revealed that the overall prevalence of Cryptosporidium infection was 29.90% (151/505), with a prevalence of 37.67% (55/146) and 26.74% (96/359) in diarrheal and nondiarrheal samples, respectively; these differences were significant. The overall prevalence of Cryptosporidium infection at the 6 sampling sites ranged from 0 to 47.06% and that among the 4 age groups ranged from 18.50 to 43.81%. SSU rRNA sequence analysis and RFLP analysis revealed the presence of 4 Cryptosporidium species, namely, C. bovis (44.37%), C. andersoni (35.10%), C. ryanae (21.85%), and C. parvum (11.92%), along with a mixed infection involving two or three Cryptosporidium species. Cryptosporidium bovis or C. andersoni was the most common cause of infection in the four age groups. The subtype of C. parvum was successfully identified as IIdA via gp60 analysis; all isolates were identified as the subtype IIdA19G1.

CONCLUSIONS

To the best of our knowledge, this is the first report of dairy cattle infected with four Cryptosporidium species in Inner Mongolia, China, along with a mixed infection involving two or three Cryptosporidium species, with C. bovis and C. andersoni as the dominant species. Moreover, this is the first study to identify C. parvum subtype IIdA19G1 in cattle in Inner Mongolia. Our study findings provide detailed information on molecular epidemiological investigation of bovine cryptosporidiosis in Inner Mongolia, suggesting that dairy cattle in this region are at risk of transmitting cryptosporidiosis to humans.

First identification of Cryptosporidium parvum virus 1 (CSpV1) in various subtypes of Cryptosporidium parvum from diarrheic calves, lambs and goat kids from France

Cryptosporidium spp. remain a major cause of waterborne diarrhea and illness in developing countries and represent a significant burden to farmers worldwide. Cryptosporidium parvum virus 1 (CSpV1), of the genus Cryspovirus, was first reported to be present in the cytoplasm of C. parvum in 1997. Full-length genome sequences have been obtained from C. parvum from Iowa (Iowa), Kansas (KSU) and China. We aimed at characterizing the genome of CSpV1 from France and used sequence analysis from Cryptosporidium isolates to explore whether CSpV1 genome diversity varies over time, with geographical sampling location, C. parvum genetic diversity, or ruminant host species. A total of 123 fecal samples of cattle, sheep and goats were collected from 17 different French departments (57 diseased animal fecal samples and 66 healthy animal fecal samples). Subtyping analysis of the C. parvum isolates revealed the presence of two zoonotic subtype families IIa and IId. Sequence analysis of CSpV1 revealed that all CSpV1 from France, regardless of the subtype of C. parvum (IIaA15G2R1, IIaA17G2R1 and IIdA18G1R1) are more closely related to CSpV1 from Turkey, and cluster on a distinct branch from CSpV1 collected from C. parvum subtype IIaA15G2R1 from Asia and North America. We also found that samples collected on a given year or successive years in a given location are more likely to host the same subtype of C. parvum and the same CSpV1 strain. Yet, there is no distinct clustering of CSpV1 per French department or ruminants, probably due to trade, and transmission of C. parvum among host species. Our results point towards (i) a close association between CSpV1 movement and C. parvum movement, (ii) recent migrations of C. parvum among distantly located departments and (iii) incidental transmission of C. parvum between ruminants. All together, these results provide insightful information regarding CSpV1 evolution and suggest the virus might be used as an epidemiological tracer for C. parvum. Future studies need to investigate CSpV1's role in C. parvum virulence and on subtype ability to infect different species.

Occurrence and risk factors associated with gastrointestinal parasitism in horses reared in different systems

To facilitate exploration of the immense range of gastrointestinal parasites in horses and the impact of parasitism on equine health, the present study aimed to evaluate the occurrence and risk factors associated with these infections in horses reared in different management systems in the state of Santa Catarina, Brazil. Samples were collected from 208 horses: 91 from extensive, 64 from semi-extensive, and 53 from intensive rearing systems. The identified helminths included those of the Strongylida order (80.29%), Parascaris equorum (3.36%), Oxyuris equi (4.33%), and Anoplocephala spp. (1.92%). By analyzing the coproculture results to differentiate among Strongylida order parasites, species such as Strongylus vulgaris, S. edentatus, S. equinus, Triodontophorus spp., and Trichostrongylus axei, in addition to members of the Cyathostominae subfamily, which include Gyalocephalus capitatus and Poteriostomum spp., were identified. The only positive sample of protozoa was that of Cryptosporidium spp. (13%). Regarding the rearing system, animals in the extensive system had a higher proportion of infected horses and a higher chance of infection than those in the other systems. For the variable co-grazing with cattle, only cyathostomins showed a significant difference with relatively low infection risk in co-grazing. Overall, the present study demonstrated a high occurrence of equine gastrointestinal parasites, especially those of the Strongylida order, with emphasis on small strongylids. In addition, analyzing factors associated with infection showed that management variables are important for controlling parasitism in horses.

Modeling cryptosporidiosis in humans and cattle: Deterministic and stochastic approaches

Cryptosporidiosis is a zoonotic disease caused by Cryptosporidium. The disease poses a public and veterinary health problem worldwide. A deterministic model and its corresponding continuous time Markov chain (CTMC) stochastic model are developed and analyzed to investigate cryptosporidiosis transmission dynamics in humans and cattle. The basic reproduction number R 0 for the deterministic model and stochastic threshold for the CTMC stochastic model are computed by the next generation matrix method and multitype branching process, respectively. The normalized forward sensitivity index method is used to determine the sensitivity index for each parameter in R 0 . Per capita birth rate of cattle, the rate of cattle to acquire cryptosporidiosis infection from the environment and the rate at which infected cattle shed Cryptosporidium oocysts in the environment play an important role in the persistence of the disease whereas Cryptosporidium oocysts natural death rate, cattle recovery rate and cattle natural death rate are most negative sensitive parameters in the dynamics of cryptosporidiosis. Numerical results for CTMC stochastic model show that the likelihood of cryptosporidiosis extinction is high when it arises from an infected human. However, there is a major outbreak if cryptosporidiosis emerges either from infected cattle or from Cryptosporidium oocysts in the environment or when it emerges from all three infectious compartments. Therefore to control the disease, control measures should focus on maintaining personal and cattle farm hygiene and decontaminating the environment to destroy Cryptosporidium oocysts.

Occurrence and limited zoonotic potential of Cryptosporidium spp., Giardia duodenalis, and Balantioides coli infections in free-ranging and farmed wild ungulates in Spain

Little information is currently available on the occurrence and molecular diversity of the enteric protozoan parasites Cryptosporidium spp., Giardia duodenalis, and Balantioides coli in wild ungulates and the role of these host species as potential sources of environmental contamination and consequent human infections. The presence of these three pathogens was investigated in eight wild ungulate species present in Spain (genera Ammotragus, Capra, Capreolus, Cervus, Dama, Ovis, Rupicapra, and Sus) by molecular methods. Faecal samples were retrospectively collected from free-ranging (n = 1058) and farmed (n = 324) wild ungulates from the five Spanish bioregions. Overall infection rates were 3.0% (42/1382; 95% CI: 2.1-3.9%) for Cryptosporidium spp., 5.4% (74/1382; 95% CI: 4.2-6.5%) for G. duodenalis, and 0.7% (9/1382; 95% CI: 0.3-1.2%) for B. coli. Cryptosporidium infection was detected in roe deer (7.5%), wild boar (7.0%) and red deer (1.5%), and G. duodenalis in southern chamois (12.9%), mouflon (10.0%), Iberian wild goat (9.0%), roe deer (7.5%), wild boar (5.6%), fallow deer (5.2%) and red deer (3.8%). Balantioides coli was only detected in wild boar (2.5%, 9/359). Sequence analyses revealed the presence of six distinct Cryptosporidium species: C. ryanae in red deer, roe deer, and wild boar; C. parvum in red deer and wild boar; C. ubiquitum in roe deer; C. scrofarum in wild boar; C. canis in roe deer; and C. suis in red deer. Zoonotic assemblages A and B were detected in wild boar and red deer, respectively. Ungulate-adapted assemblage E was identified in mouflon, red deer, and southern chamois. Attempts to genotype samples positive for B. coli failed. Sporadic infections by canine- or swine-adapted species may be indicative of potential cross-species transmission, although spurious infections cannot be ruled out. Molecular evidence gathered is consistent with parasite mild infections and limited environmental contamination with (oo)cysts. Free-ranging wild ungulate species would not presumably play a significant role as source of human infections by these pathogens. Wild ruminants do not seem to be susceptible hosts for B. coli.

Molecular detection and characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi infections in dromedary camels (Camelus dromedaries) in Egypt

Introduction

Few studies have investigated the occurrence of microeukaryotic gut parasites in dromedary camels in Egypt, and the majority of these investigations are based on microscopic analysis of fecal material.

Methods

Herein, we assessed the occurrence, molecular diversity, and zoonotic potential of protozoan (Cryptosporidium spp. and Giardia duodenalis) and microsporidian (Enterocytozoon bieneusi) pathogens in individual fecal samples (n = 102) of dromedary camels with (n = 26) and without (n = 76) diarrhea from Aswan Governorate, Upper Egypt. Other factors possibly associated with an increased risk of infection (geographical origin, sex, age, and physical condition) were also analyzed. The SSU rRNA or ITS genes were targeted by molecular (PCR and Sanger sequencing) techniques for pathogen detection and species identification.

Results and discussion

The most abundant species detected was G. duodenalis (3.9%, 4/102; 95% CI: 1.1-9.7), followed by Cryptosporidium spp. (2.9%, 3/102; 95% CI: 0.6-8.4). All samples tested negative for the presence of E. bieneusi. Sequence analysis data confirmed the presence of zoonotic C. parvum (66.7%, 2/3) and cattle-adapted C. bovis (33.3%, 1/3). These Cryptosporidium isolates, as well as the four Giardia-positive isolates, were unable to be amplified at adequate genotyping markers (Cryptosporidium: gp60; Giardia: gdh, bg, and tpi). Camels younger than 2 years old were significantly more likely to harbor Cryptosporidium infections. This connection was not statistically significant, although two of the three cryptosporidiosis cases were detected in camels with diarrhea. The spread of G. duodenalis infections was unaffected by any risk variables studied. This is the first report of C. parvum and C. bovis in Egyptian camels. The finding of zoonotic C. parvum has public health implications since camels may function as sources of oocyst pollution in the environment and potentially infect livestock and humans. Although preliminary, this study provides useful baseline data on the epidemiology of diarrhea-causing microeukaryotic parasites in Egypt. Further research is required to confirm and expand our findings in other animal populations and geographical regions of the country.

Prevalence and molecular analysis of Cryptosporidium spp. collected from surface water

Cryptosporidium is an obligate intracellular parasite reported from all over the world. This protozoan infects a wide range of animals as well as humans. Cryptosporidium parvum and Cryptosporidium hominis are the most prevalent infecting species with mild and self-limiting infection in healthy people. The protozoan oocyst is resistant to common water purifiers. Based on emerging evidence, Cryptosporidium is one of waterborne parasites considered a major public health problem in developing and developed countries. In this study, 42 samples were collected from 14 rivers in the catchment area of Lake Urmia in northwest of Iran. Moreover, amplification of SSU rRNA gene was performed, and polymerase chain reaction products were sequenced. The results of sequencing and comparing the sequences with those in the GenBank revealed that all the 17 positive samples were C. parvum, a zoonotic species and one of the most frequent human-infecting species. Considering these data, it is highly important to inhibit the spread of this protozoan by treating livestock and preventing human and animal effluents from entering the water.

Global prevalence of Cryptosporidium spp. in pigs: a systematic review and meta-analysis

Cryptosporidium spp. are significant opportunistic pathogens causing diarrhoea in humans and animals. Pigs are one of the most important potential hosts for Cryptosporidium. We evaluated the prevalence of Cryptosporidium in pigs globally using published information and a random-effects model. In total, 131 datasets from 36 countries were included in the final quantitative analysis. The global prevalence of Cryptosporidium in pigs was 16.3% (8560/64 809; 95% confidence interval [CI] 15.0–17.6%). The highest prevalence of Cryptosporidium in pigs was 40.8% (478/1271) in Africa. Post-weaned pigs had a significantly higher prevalence (25.8%; 2739/11 824) than pre-weaned, fattening and adult pigs. The prevalence of Cryptosporidium was higher in pigs with no diarrhoea (12.2%; 371/3501) than in pigs that had diarrhoea (8.0%; 348/4874). Seven Cryptosporidium species (Cryptosporidium scrofarum, Cryptosporidium suis, Cryptosporidium parvum, Cryptosporidium muris, Cryptosporidium tyzzeri, Cryptosporidium andersoni and Cryptosporidium struthioni) were detected in pigs globally. The proportion of C. scrofarum was 34.3% (1491/4351); the proportion of C. suis was 31.8% (1385/4351) and the proportion of C. parvum was 2.3% (98/4351). The influence of different geographic factors (latitude, longitude, mean yearly temperature, mean yearly relative humidity and mean yearly precipitation) on the infection rate of Cryptosporidium in pigs was also analysed. The results indicate that C. suis is the dominant species in pre-weaned pigs, while C. scrofarum is the dominant species in fattening and adult pigs. The findings highlight the role of pigs as possible potential hosts of zoonotic cryptosporidiosis and the need for additional studies on the prevalence, transmission and control of Cryptosporidium in pigs.

Detection of Endoparasites in Non-Native Raccoons from Central Italy

The raccoon (Procyon lotor) is a carnivore native to North and Central America, gradually introduced into Asia and Europe, including Italy. It is an important carrier of multiple endoparasites, both Protozoa and Helminths, some of them being zoonotic. The aim of this study was to investigate the endoparasites of the non-native raccoon population of Central Italy. Sixty-two raccoons were collected by local competent authorities (sixty trapped and euthanized, two found dead) and subjected to necroscopic examination. Carcasses underwent a broad parasitological investigation, including coprological techniques (macroscopic examination of the gastrointestinal tract, lungs, trachea, and heart, Flotac^®, Baermann test, and immunofluorescence for Giardia duodenalis and Cryptosporidium spp.), research on respiratory/urinary capillariosis and artificial digestion for Trichinella spp. larvae, and a histopathological examination of the ileum. Ascarid parasites were further identified at the species level using a next-generation sequencing-based amplicon sequencing approach. The results showed the presence of different Protozoa and Nematodes: Baylisascaris procyonis (26/62; 41.9%), Pearsonema sp. (6/62; 9.6%), Capillariidae (6/62; 9.6%), Eimeria sp. (2/62; 3.2%), Cryptosporidium sp. (2/62; 3.2%), and Ancylostomatidae (2/62; 3.2%). B. procyonis is an emerging helminthic zoonotic agent considered a serious concern for public and animal health, given the possibility of its transmission to paratenic hosts, including humans and pets. The demonstrated role of the raccoon as a multi-parasite carrier should be an incentive to continuing the eradication/control of this alien species, and supports the need to implement related disease surveillance programs.

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.

Molecular evaluation of Cryptosporidium spp. among breeding calves of Lorestan province Western Iran

BACKGROUND

Cryptosporidium spp. are opportunistic intestinal protozoans with global distribution and are of great importance as zoonotic protozoans are common to humans and domestic animals, including cattle and calves. Identification and detection of parasite species using precise methods including molecular methods can be an effective step in treating and controlling parasites.

OBJECTIVES

This study aimed to investigate the prevalence of Cryptosporidium among breeding calves of Khorramabad city, Lorestan province, Western Iran, using PCR.

METHODS

The faecal samples were taken from 181 healthy and diarrhoeal calves and after the Ziehl Neelsen Acid-fast staining and microscopic evaluation, the genomic DNA was extracted for molecular evaluations. To detect Cryptosporidium species, specific primers targeting the SAM-1 gene of Cryptosporidium and a commercial master mix were used for PCR.

RESULTS

Out of 181 faecal samples of breeding calves in Khorramabad city, 9 samples (5%) were positive for Cryptosporidium spp. using the PCR method. Statistical analysis of the data showed that there was no significant statistical relationship between Cryptosporidium infection of the calves and variables of age, breed, type of water consumption, clinical signs of diarrhoea, and sampling location, while parasite infection had a significant relationship with calf gender so that all Cryptosporidium positive samples were from male calves (p ≤ 0.05).

CONCLUSIONS

Considering the presence of Cryptosporidium infection, the region's traditional grazing system, and the close relationship between livestock and humans, there is a possibility of human infection in the region. So preventive measures such as periodic animal testing with sensitive and accurate diagnostic techniques including PCR, pharmacological treatment of livestock, water hygiene and the use of industrial grazing instead of traditional grazing to improve the hygiene of food consumed by livestock are recommended.

Cryptosporidiosis: From Prevention to Treatment, a Narrative Review

Cryptosporidiosis is a water- and food-borne zoonotic disease caused by the protozoon parasite of the genus Cryptosporidium. C. hominis and C. parvum are the main two species causing infections in humans and animals. The disease can be transmitted by the fecal-oral route as well as the respiratory route. The infective stage (sporulated oocysts) is resistant to different disinfectants including chlorine. Currently, no effective therapeutic drugs or vaccines are available to treat and control Cryptosporidium infection. To prevent cryptosporidiosis in humans and animals, we need to understand better how the disease is spread and transmitted, and how to interrupt its transmission cycle. This review focuses on understanding cryptosporidiosis, including its infective stage, pathogenesis, life cycle, genomics, epidemiology, previous outbreaks, source of the infection, transmission dynamics, host spectrum, risk factors and high-risk groups, the disease in animals and humans, diagnosis, treatment and control, and the prospect of an effective anti-Cryptosporidium vaccine. It also focuses on the role of the One Health approach in managing cryptosporidiosis at the animal-human-environmental interface. The summarized data in this review will help to tackle future Cryptosporidium infections in humans and animals and reduce the disease occurrence.

Prevalence of Cryptosporidium spp. infection in working horses in Egypt.. [DOI: 10.21203/rs.3.rs-2363022/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Working horses support the livelihoods of smallholder farmers in Egypt but can pose potential zoonotic risk to their handlers such as cryptosporidiosis. Working horses were recruited into the study from 37 villages/areas in two Egyptian governorates. Faecal samples were collected from 607 horses and were examined for Cryptosporidium spp. infection using modified Zielh-Neelsen staining technique. Data about signalment, concurrent disease and level of strongyle infection were collected. The prevalence of Cryptosporidium spp. infection was calculated using a bootstrap method and potential risk factors for the infection were investigated using mixed-effects logistic regression models that included the sampling location as a random-effects variable. The prevalence of Cryptosporidium spp. infection was 28.7% (95% confidence interval = 23.5–33.9). None of the variables investigated including age and sex of the animals were associated with the risk of the infection. The study identified greater prevalence of Cryptosporidium spp. infection in the study area and further studies may be required to genotype these parasites. Personal hygiene such as hand sanitation should be practiced when managing these horses.

Diagnosis and control of cryptosporidiosis in farm animals

Cryptosporidium is a pathogenic protozoan parasite infecting the gastrointestinal epithelium of human and animal hosts. In farm animals, cryptosporidiosis causes significant economic losses including deaths in newborn animals, retarded growth, increased labor involved and high cost of drugs. The detection of Cryptosporidium oocysts in fecal samples is traditionally dependent on examination of stained slides by light microscope or by advanced microscopical tools such as: electron microscopy and phase contrast microscopy. Immunological diagnosis using either antibody or antigen detection could offer high sensitivity and specificity. Examples for these tests are Enzyme Linked Immunosorbent Assay (ELISA), Immunochromatographic tests, Immunochromatographic lateral flow (ICLF), Immunofluorescence assays (IFA) and Flow cytometry coupled with cell sorting. Molecular methods could differentiate species and genotypes of Cryptosporidium and help in studying the epidemiological features of this parasite with rapid, simple and sensitive procedures. Nanotechnology-based platforms could improve the sensitivity and specificity of other detection methods like: ELISA, ICLF, IFA and polymerase chain reaction. As the available prophylactic and therapeutic drugs or natural products treatments are insufficient and no approved vaccines are available, the best approach to control this parasite is by following firm hygienic measures. Many vaccine attempts were performed using hyperimmune colostrum, live or attenuated vaccines, recombinant and Deoxyribonucleic acid vaccines. Also, Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 technology could help in Cryptosporidium genome editing to improve drug and vaccine discovery. Another approach that could be useful for assigning drug targets is metabolomics. Probiotics were also used successfully in the treatment of acute diarrhea and they proved a limiting effect on cryptosporidiosis in animal models. In addition, nanotherapy-based approaches could provide a good strategy for improving the potency of any type of drugs against Cryptosporidium and give good anti-cryptosporidial effects. In conclusion, accurate diagnosis using advanced techniques is the key to the control and prevention of cryptosporidiosis.

Utilization of health belief model in comprehending diarrheal disease dynamics: a case of cryptosporidiosis in Uganda

BACKGROUND

Diarrheal diseases contribute greatly to the reported global childhood mortality and morbidity with related social, economic consequences. This study was conducted to analyze the utilization of the Health Belief Model (HBM) theory to comprehend diarrheal disease dynamics in Uganda.

METHODS

Our study utilized a qualitative cross-sectional design among adult livestock farmers in selected farming communities. A total of 80 individuals were recruited and interviewed through Focus Discussion Groups (FDGs) (n = 6) and Key Informant Interviews (KIIs) (n = 8) to evaluate diarrheal disease dynamics. The scope of dynamics included but not limited to exposure risks, knowledge, and attitudes. Our results were presented using the five (5) constructs of the HBM.

RESULTS

Perceived susceptibility; communities believed that both humans and their animals are at high risk of different kinds of diarrheal infections. The farmers believed that majority of these diarrhea infections are hard to treat especially among animals. Perceived severity; farmers believed that diarrheal diseases are characterized by loss of weight, fever, emaciation, dry eyes, severe prolonged diarrhea and sudden death. Perceived barriers; limited knowledge and misconceptions about the diarrheal infections were great inhibitors to successful disease prevention and control. Self-efficacy; farmers had fear of laxity that interventions being suggested and put in place to curb diarrheal diseases such as cryptosporidiosis would wither away with time thus endemicity of the problem in the community. Modifying factors and cues to action; most of the farmers treat animals by themselves based on; probability, traditional knowledge and previous experience.

CONCLUSION

Sustained public health interventional activities should therefore be undertaken by both human and animal health sectors with maximum community involvement. Communities suggested the need to increase preventive measures and promote household hygiene efforts to always wash hands with soap and running water in order to reduce the burden of diarrhea diseases such as cryptosporidiosis.

Analysis of supplemental wildlife feeding in Mississippi and environmental gastrointestinal parasite load

Wildlife species are host to a variety of gastrointestinal parasites (GIPs). Artificially concentrating animals may increase the risk of disease spread due to increased GIP load and associated environmental load. Supplemental feeding of deer is common among hunters and known to concentrate animals, but there is limited knowledge of how it affects GIP environmental load. GIP load was compared between ecologically-equivalent pairs of sites in Mississippi with and without year-round supplemental feeding (average distance between pairs = 147 m). During May-August in 2019 and 2020, feces from white-tailed deer and raccoons were collected and examined for the presence of nematodes, coccidia, Giardia spp., Cryptosporidium spp., and Baylisascaris procyonis. On average, fed sites had 8 more deer (241% increase) and 2 more raccoon fecal piles (540% increase) than unfed sites. Average parasite loads for individual fecal samples did not differ between fed and unfed sites, but the greater number of deer and raccoon fecal piles at fed sites (p < 0.0001) produced 231% and 308% greater environmental loads of nematodes and coccidia, respectively. Spin feeders, the only feeder type that distributed feed on the ground, had 326% more coccidia in feces on average compared to other feeder types (p < 0.03). These results show that supplemental feeding of white-tailed deer, especially with spin feeders, increases environmental loads of GIP and the potential for transmission of parasitic diseases.

Molecular identification of Cryptosporidium species in Canadian post-weaned calves and adult dairy cattle

Cryptosporidium is a zoonotic protozoan parasite that is distributed globally and impacts both human and animal health. There are over 40 species of Cryptosporidium described to date, of which four (C. parvum, C. bovis, C. ryanae and C. andersoni) are routinely reported in cattle. The goal of this study was to identify the Cryptosporidium species infecting dairy cattle from across Canada using cow fecal samples and post-weaned calf rectal swabs obtained through the Canadian National Dairy Study. A total of 353 cattle samples (117 pooled rectal fecal swabs from post-weaned calves and 236 cow fecal samples) from 175 herds across the 10 Canadian provinces were analysed by targeting Cryptosporidium's small subunit ribosomal RNA (SSU rRNA or 18S) gene. Herd prevalence of Cryptosporidium was 27.4% nationally, ranging from 0% in Saskatchewan (SK) to 62% in Prince Edward Island (PE). The national prevalence of Cryptosporidium cattle infections was 15.4% in pooled rectal fecal swab samples from post-weaned calves and 16.1% in adult cows. Sanger sequence analysis of the SSU rRNA gene target revealed that C. bovis, C. andersoni and C. ryanae occurred in both adults and post-weaned calves, with C. bovis as the predominant species detected in pooled fecal swab samples of post-weaned calves (9/18, 50%) and C. andersoni as the predominant species in cows (25/38, 66%). Cryptosporidium parvum was not observed in any of the pooled rectal swab samples from post-weaned calves but was observed in one mixed infection of C. bovis/C. parvum in an adult cow. The fifth species identified in this study was C. muris and was present in two adult cows. Low concentrations of oocyst equivalents, as measured by quantitative real-time PCR (qPCR) of the SSU rRNA gene copy number, were observed in a subset of cattle samples. Cryptosporidium andersoni concentrations varied from province to province, with the widest range and highest counts in cows from PE. In conclusion, oocysts from Cryptosporidium species observed in this study are shed into the environment, contributing to the environmental load. However, the Cryptosporidium species in the post-weaned calves and cows found in this study pose a lower risk to the dairy cattle than if they were infected with C. parvum. Similarly, these Cryptosporidium species pose only a small risk to public health as the three species are infrequently reported in humans globally and have not been reported in Canadians to date.

Molecular detection and genetic characteristics of Cryptosporidium spp. in Chinese racehorses

BACKGROUND

Cryptosporidium is a protozoan parasite causing diarrhoea in humans and animals. Although Cryptosporidium has been found in domestic horses (farmed or kept at pasture), there has been only one published study of Cryptosporidium infections in Chinese racehorses, which was restricted to a very small geographical area.

OBJECTIVES

To investigate the presence of Cryptosporidium spp. in the faeces of racehorses in China and to perform molecular characterisation of the parasite.

STUDY DESIGN

Cross-sectional.

METHODS

A total of 621 fresh faecal samples were collected for DNA extraction from racehorses at 17 equestrian clubs from 12 provinces of China from December 2016 to May 2018. All the DNA were analysed for the presence of Cryptosporidium species/genotypes and subtypes by PCR amplification of the small subunit ribosomal RNA and 60 kDa glycoprotein genes, respectively.

RESULTS

PCR analysis revealed that 11 samples (1.8%) were positive for Cryptosporidium spp. Among them 7 samples were identified as C. parvum and 4 were C. hominis. The C. parvum isolates were identified as subtype IIdA14G1 (n = 4) and IIdA15G1 (n = 3), while all C. hominis isolates were identified as subtype IkA18G1 (n = 4).

MAIN LIMITATIONS

A single faecal sample from each horse was used instead of multiple samples that could improve the detection rates of the parasite.

CONCLUSIONS

Although Cryptosporidium infection rate was relatively low in the investigated racehorses, the presence of zoonotic subtypes IIdA14G and 1IIdA15G1 of C. parvum and IkA18G1 of C. hominis, suggesting that these animals are a potential source of Cryptosporidium in humans.

Cryptosporidium species in non-human animal species in Latin America: Systematic review and meta-analysis

Cryptosporidiosis is an infection caused by a protozoon that inhabits the gastrointestinal tract. More than forty valid species have been described in the genus Cryptosporidium, infecting a broad range of hosts around the world, some with zoonotic transmission and others with predominant anthroponotic transmission. Prevalence studies conducted in Latin American countries have been specific, without consolidating information on species prevalences. Thus, the aim of this study was to perform a systematic review and meta-analysis addressing the prevalence of Cryptosporidium species in animals in Latin America. The estimated pooled prevalence rate for cryptosporidiosis in animals, by means of meta-analysis with a random-effects model, based on species identification, was 18.0% (95% CI 11.0%-27.0%) with high heterogeneity. The estimated overall prevalence was 20.3% (36/177) in pets, 19.9% (1309/6573) in livestock animals and 23.9% (954/3995) in exotic/captive animals. Evidence of circulation of 16 Cryptosporidium species was found in five Latin American countries: Brazil, Colombia, Chile, Argentina and Mexico. Through meta-analysis with a random-effects model, the pooled prevalence rate for Cryptosporidium parvum was 0.7% (95% CI 0.2%-2.4%). Cryptosporidium felis (8.5%) was the most prevalent species in pets, C. parvum (10.3%) in livestock animals and Cryptosporidium galli (17.6%) in exotic/captive animals. C. parvum was the species with the greatest geographical dispersion, which can be explained by its eurixenic and zoonotic potential. Few studies on cryptosporidiosis in animals in Latin America were found, which shows that there is a need for investment in and expansion of studies on this parasite. The pooled prevalence of C. parvum in Latin America and its wide circulation are similar to what has been observed in other developing regions, which reaffirms the importance of this species as the cause of a neglected, emerging and zoonotic parasitosis.

High Occurrence of Zoonotic Subtypes of Cryptosporidiumparvum in Cypriot Dairy Farms

Cryptosporidium parvum is one of the major causes of neonatal calf diarrhoea resulting in reduced farm productivity and compromised animal welfare worldwide. Livestock act as a major reservoir of this parasite, which can be transmitted to humans directly and/or indirectly, posing a public health risk. Research reports on the prevalence of Cryptosporidium in ruminants from east Mediterranean countries, including Cyprus, are limited. This study is the first to explore the occurrence of Cryptosporidium spp. in cattle up to 24 months old on the island of Cyprus. A total of 242 faecal samples were collected from 10 dairy cattle farms in Cyprus, all of which were screened for Cryptosporidium spp. using nested-PCR amplification targeting the small subunit of the ribosomal RNA (18S rRNA) gene. The 60 kDa glycoprotein (gp60) gene was also sequenced for the samples identified as Cryptosporidium parvum-positive to determine the subtypes present. The occurrence of Cryptosporidium was 43.8% (106/242) with at least one positive isolate in each farm sampled. Cryptosporidium bovis, Cryptosporidium ryanae and C. parvum were the only species identified, while the prevalence per farm ranged from 20–64%. Amongst these, the latter was the predominant species, representing 51.8% of all positive samples, followed by C. bovis (21.7%) and C. ryanae (31.1%). Five C. parvum subtypes were identified, four of which are zoonotic—IIaA14G1R1, IIaA15G1R1, IIaA15G2R1 and IIaA18G2R1. IIaA14G1R1 was the most abundant, representing 48.2% of all C. parvum positive samples, and was also the most widespread. This is the first report of zoonotic subtypes of C. parvum circulating in Cyprus. These results highlight the need for further research into the parasite focusing on its diversity, prevalence, host range and transmission dynamics on the island.

Identification, molecular characterization and factors associated with occurrences of Cryptosporidium spp. in calves on dairy farms in Brazil

Cattle are an important source of zoonotic species of Cryptosporidium for humans. The aim of this study was to investigate the presence of Cryptosporidium, identify the species and determine the risk factors relating to environment, animals and management among dairy calves in eight Brazilian states. A total of 408 fecal samples from calves aged 1-60 days were analyzed. An epidemiological questionnaire was completed. Sample screening was performed using Ziehl-Neelsen technique and the positive samples were subjected to nested PCR. Cryptosporidium species were identified by means of the PCR-RFLP technique, using SSPI, ASEI and MBOII enzymes. The Ziehl-Neelsen technique showed that 89.7% (35/39) of the farms and 52.9% (216/408) of the samples were positive. Through nested PCR, these protozoa were detected in 54.6% of the samples. The 56 samples subjected to PCR-RFLP presented Cryptosporidium parvum. There was higher prevalence of the parasite in animals aged 7 to 28 days (62.6%). Diarrhea, ages between seven and 28 days and a spring water source were factors associated with the risk of infection. The calf hutch-type management system was associated with reduced infection. These findings demonstrate the high level of Cryptosporidium spp. circulation in cattle herds and the predominance of the species C. parvum.

Cryptosporidium spp. in wild murids (Rodentia) from Corsica, France

Cryptosporidium spp. are worldwide protozoan parasites that can affect to a broad range of vertebrate hosts, including rodents. In the island of Corsica (France), there are no previous data about these protozoa infecting wild rodents. To estimate the distribution and occurrence, a total of 117 wild murine rodents of the species Rattus rattus (84), Mus musculus domesticus (21), Apodemus sylvaticus (11), and Rattus norvegicus (1) were captured in 24 different biotopes. Fecal samples were screened for Cryptosporidium spp. by nested PCR to amplify an 830 bp fragment of the 18S rRNA gene. As general occurrence, 15.4% of the rodents analyzed were positive for Cryptosporidium spp., being detected widely distributed along the island in R. rattus (17.6%) and M. m. domesticus (14.3%). Cryptosporidium viatorum, Cryptosporidium sp. rat genotype II, and Cryptosporidium sp. rat genotype III were successfully identified in R. rattus. The results herein reported provide the first data on Cryptosporidium spp. in wild murine species from a Mediterranean island and constitute the first report of the zoonotic species C. viatorum in R. rattus. Although a low occurrence of Cryptosporidium spp. in murids was obtained and only in one animal the zoonotic species C. viatorum was identified, our results highlight that wild murine rodents from Corsica could mediate in the maintenance and transmission of this protozoan to the environment and other hosts including humans and animals. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rodents from Corsica and their possible public health repercussions.

An Update on Zoonotic Cryptosporidium Species and Genotypes in Humans

The enteric parasite, Cryptosporidium is a major cause of diarrhoeal illness in humans and animals worldwide. No effective therapeutics or vaccines are available and therefore control is dependent on understanding transmission dynamics. The development of molecular detection and typing tools has resulted in the identification of a large number of cryptic species and genotypes and facilitated our understanding of their potential for zoonotic transmission. Of the 44 recognised Cryptosporidium species and >120 genotypes, 19 species, and four genotypes have been reported in humans with C. hominis, C. parvum, C. meleagridis, C. canis and C. felis being the most prevalent. The development of typing tools that are still lacking some zoonotic species and genotypes and more extensive molecular epidemiological studies in countries where the potential for transmission is highest are required to further our understanding of this important zoonotic pathogen. Similarly, whole-genome sequencing (WGS) and amplicon next-generation sequencing (NGS) are important for more accurately tracking transmission and understanding the mechanisms behind host specificity.

Taxonomy and molecular epidemiology of Cryptosporidium and Giardia - a 50 year perspective (1971-2021)

The protozoan parasites Cryptosporidium and Giardia are significant causes of diarrhoea worldwide and are responsible for numerous waterborne and foodborne outbreaks of diseases. Over the last 50 years, the development of improved detection and typing tools has facilitated the expanding range of named species. Currently at least 44 Cryptosporidium spp. and >120 genotypes, and nine Giardia spp., are recognised. Many of these Cryptosporidium genotypes will likely be described as species in the future. The phylogenetic placement of Cryptosporidium at the genus level is still unclear and further research is required to better understand its evolutionary origins. Zoonotic transmission has long been known to play an important role in the epidemiology of cryptosporidiosis and giardiasis, and the development and application of next generation sequencing tools is providing evidence for this. Comparative whole genome sequencing is also providing key information on the genetic mechanisms for host specificity and human infectivity, and will enable One Health management of these zoonotic parasites in the future.

Prevalence and Novel Genotypes Identification of Enterocytozoon bieneusi in Dairy Cattle in Yunnan Province, China

Simple Summary

We first report the prevalence of Enterocytozoon bieneusi in Holstein Cows and dairy buffalo in Yunnan province of China, with a percentage of positivity of 0.59% (5/841). Two novel zoonotic potential genotypes of E. bieneusi were found. We analyzed the different influencing factors (region, season, variety, breeding mode, gender, age), but the differences were not statistically significant.

Abstract

Enterocytozoon bieneusi is a fungus-like protist parasite that can cause diarrhea and enteric diseases. The infection of E. bieneusi has been reported in many host species, including cattle and humans. However, information on prevalence and genotype distribution of E. bieneusi in dairy cattle in Yunnan province in China is still absent. In this study, 490 Holstein Cows and 351 dairy buffalo fecal samples were collected from three regions in Yunnan province, China. By using nest-PCR that targets the internal transcribed spacer (ITS), we found that the prevalence of E. bieneusi was 0.59% (5/841). DNA sequence analysis showed that five E. bieneusi genotypes were identified in this study, including two novel genotypes, YNDCEB-90 and YNDCEB-174, and three known genotypes (I, J, BEB4). Phylogenetic analysis revealed that two novel genotypes, YNDCEB-90 and YNDCEB-174, were clustered into Group 1, representing the zoonotic potential. The remaining genotypes I, J, and BEB4, which are the most frequent genotypes of E. bieneusi infection in cattle and lead to E. bieneusi infection in humans, belonged to Group 2. Although the lower prevalence of E. bieneusi was detected in dairy cattle in Yunnan province, it indicates that dairy cattle should be considered to be one of the potential hosts for transmitting E. bieneusi to humans. These findings are important for the development of effective prevention strategies for microsporidiosis.

Cryptosporidium infection in humans and animals from Iraq: A review

The apicomplexan parasite Cryptosporidium causes serious diarrheal disease in humans and animals worldwide. The present review summarizes epidemiological and molecular studies as well as the clinical disease burden of natural Cryptosporidium infections in humans and animals from Iraq. Retrieved reports regarding cryptosporidiosis in Iraq indicated that the disease is highly prevalent in humans and animals, but the results extracted from these reports are confusing and mostly employed traditional methodologies for the detection of Cryptosporidium infective stage, the oocysts, in clinical samples. Many screened surveys represent point prevalence studies, which described diarrhea in infants and children due to cryptosporidiosis; however, other pathogens causing diarrhea were not excluded. High prevalence of Cryptosporidium oocysts was recovered from many studies from different environmental matrices in different parts of Iraq including drinking tap water, which facilitates its transmission to humans and animals. Reports on molecular characterization of different Cryptosporidium species which exist in Iraq are few but both Cryptosporidium hominis and Cryptosporidium parvum were detected in humans and the latter was more prevalent in isolates from cattle, sheep, goats and birds. A national study on adequate numbers of samples from different hosts and environmental matrices, and employing advanced diagnostic methodologies is required to precisely detect the epidemiological situation of cryptosporidiosis in Iraq. Furthermore, molecular genotyping studies are required to be conducted in Iraq to characterize the species and subtypes of Cryptosporidium infecting humans and animals especially during outbreaks. Therefore, Cryptosporidium parasite should be included in the routine diagnosis and surveillance system of infectious diseases in Iraq and should be regarded as an important public health problem of concern.

Detection of Zoonotic Cryptosporidium ubiquitum in Alpine Wild Ruminants

Cryptosporidium is a widespread apicomplexan protozoan of major zoonotic importance, characterized by a wide host range, and with relevant economic implications and potential negative effects on livestock and wildlife population dynamics. Considering the recent strong demographic increase of alpine ungulates, in this study, carried out in the Italian Northwestern Alps, we investigated the occurrence of Cryptosporidium spp. in these species and their potential involvement in environmental contamination with Cryptosporidium spp. oocysts. The immune-enzymatic approach revealed a Cryptosporidium prevalence of 1.7% (5/293), 0.5% (1/196) and 3.4% (4/119) in alpine chamois (Rupicapra rupicapra), red deer (Cervus elaphus) and roe deer (Capreolus capreolus), respectively. Positive samples were subjected to polymerase chain reaction (PCR) amplification for the COWP and gp60 genes. The presence of Cryptosporidium was confirmed in one chamois and four roe deer. Sequences obtained clustered within Cryptosporidium&nbsp;ubiquitum, currently recognized as an emerging zoonotic species. This finding represents the first detection of zoonotic C.&nbsp;ubiquitum in chamois and in the Alpine environment. Despite the low observed prevalences, environmental contamination by oocysts could play a role as a potential source of infections for humans and livestock.

The Mucosal Innate Immune Response to Cryptosporidium parvum, a Global One Health Issue

Cryptosporidium parvum is an apicomplexan parasite that infects the intestinal epithelium of humans and livestock animals worldwide. Cryptosporidiosis is a leading cause of diarrheal-related deaths in young children and a major cause of economic loss in cattle operations. The disease is especially dangerous to infants and immunocompromised individuals, for which there is no effective treatment or vaccination. As human-to-human, animal-to-animal and animal-to-human transmission play a role in cryptosporidiosis disease ecology, a holistic 'One Health' approach is required for disease control. Upon infection, the host's innate immune response restricts parasite growth and initiates the adaptive immune response, which is necessary for parasite clearance and recovery. The innate immune response involves a complex communicative interplay between epithelial and specialized innate immune cells. Traditional models have been used to study innate immune responses to C. parvum but cannot fully recapitulate natural host-pathogen interactions. Recent shifts to human and bovine organoid cultures are enabling deeper understanding of host-specific innate immunity response to infection. This review examines recent advances and highlights research gaps in our understanding of the host-specific innate immune response to C. parvum. Furthermore, we discuss evolving research models used in the field and potential developments on the horizon.

A systematic review and meta-analysis on the global prevalence and subtypes distribution of Blastocystis sp. infection in cattle: A zoonotic concern

Blastocystosis is an interesting parasitosis, since the parasitic infection is still seriously neglected and a considerable zoonotic evidence is emerging. Blastocystis sp. infects the intestinal lumen of humans and a wide range of animals, while there is a lack of comprehensive information on Blastocystis epidemiology in cattle worldwide. Thus, the present systematic review and meta-analysis were performed by exploring four electronic databases (PubMed, Web of Science, Scopus, and Google scholar) for relevant published papers up to 7th November 2020, utilizing a random-effects model to pool estimations and assign 95 % confidence intervals (CIs). Results of 28 studies (29 datasets) on cattle showed a 24.4 % (95 % CI: 16.9-33.9 %) prevalence for Blastocystis infection. Also, 16 out of 26 reported subtypes (STs) were isolated from cattle, with ST10 (18 datasets) as the highest-reported [32.3 % (95 % CI: 21.6-45.3)] as well as ST24 and ST25 (one study each) as the lowest-reported STs [1.4 % (95 % CI: 0.2-9.1)]. Additionally, among nine well-known zoonotic STs (ST1-ST8 and ST12), all STs except for ST8 were reported from cattle worldwide, demonstrating this animal species as a potential reservoir for human infections. Meanwhile, the overall prevalence of Blastocystis in various subgroups (publication year, WHO regions, countries, continents, and age groups) was analyzed separately. The finding of the present review article highlights the cattle as a significant source of zoonotic transmission of Blastocystis infection to humans, which must be considered for preventive measures.

Global prevalence of Cryptosporidium spp. in cats: A systematic review and meta-analysis

The One-Health approach highlights that the health of human populations is closely connected to the health of animals and their shared environment. Cryptosporidiosis is an opportunistic zoonotic disease considering as global public health concern. Cats are considered as one of potential host for transmitting the Cryptosporidium spp. infection to humans. A random-effects meta-analysis model was used to estimate the overall and the subgroup-pooled prevalence of Cryptosporidium spp. across studies, and the variance between studies (heterogeneity) were quantified by I² index. Eighty articles (including 92 datasets), from 29 countries met eligibility criteria for analysis. The pooled global prevalence (95% CI) of Cryptosporidium spp. in cats was 6% (4-8%), being highest in Africa 14% (0-91%) and lowest in South and Central America 4% (3-7%) countries. Considering the detection methods, the pooled prevalence was estimated to be 26% (1-67%) using serological detection methods, 6% (3-10%) using coproantigen detection methods, 5% (3-7%) using molecular detection methods, and 4% (3-7%) using microscopic detection methods. The highest prevalence of Cryptosporidium spp. was found in stray cats 10% (5-17%), while pet (domestic) cats 4% (3-7%) had the lowest prevalence. These results emphasize the role of cats as reservoir hosts for human-infecting Cryptosporidium spp. Prevention and control of this zoonosis in cats should receive greater attention by health officials and health policymakers, especially in countries where prevalence are highest.

Prevalence of Worldwide Neonatal Calf Diarrhoea Caused by Bovine Rotavirus in Combination with Bovine Coronavirus, Escherichia coli K99 and Cryptosporidium spp.: A Meta-Analysis

Multiple enteropathogens such as bovine rotavirus (BRV), bovine coronavirus (BCoV), Escherichia coli K99 (ETEC) and Cryptosporidium spp. (Crypto) are the most common causes of calf diarrhoea during the first 30 days of animal age. Three weighted-stratified random-effects meta-analyses were performed to calculate the worldwide prevalence of mixed infections of the causative agents (i.e., BRV-BCoV, BRV-ETEC, BRV-Crypto) and their potential influencing factors. The meta-analysis covered 41 studies (94 sub-studies) in 21 countries that determined the presence or absence of mixed infections in global calf populations. The highest worldwide estimated pooled prevalence was identified for BRV-Crypto (6.69%), followed by BRV-BCoV (2.84%), and BRV-ETEC (1.64%). The chance of detecting BCoV in calves with diarrhoea was 1.83 higher in the presence of BRV compared to calves without BRV, whereby an inhibition effect (odds ratio: 0.77) was determined between BRV and Crypto infections. The diagnostic methods were identified as a significant influencing factor in the detection of all considered mixed infections, while the other analysed factors differed in relation to their effect on prevalence. In contrast to BRV-BCoV, the prevalence of BRV-ETEC and BRV-Crypto mixed infections followed the course of individual ETEC and Crypto prevalence related to the age class of the sampled animals.

Prevalence and multilocus genotyping of Cryptosporidium spp. in cattle in Jiangxi Province, southeastern China

Cryptosporidium is a genus of single-celled protozoa, infecting a wide range of animals and humans. Although Cryptosporidium infections of cattle have been reported in some provinces in China, there is no available information on the prevalence and predominant species of Cryptosporidium in cattle in Jiangxi province. To investigate the prevalence of Cryptosporidium in cattle in Jiangxi province of China, 556 fecal samples were collected from eight farms in four cities and the SSU rRNA locus of Cryptosporidium was amplified from the DNA of each fecal sample by PCR. The overall prevalence of Cryptosporidium was 12.8% (71/556) in cattle in Jiangxi province, with 24.3% (54/222) in Nanchang city, 7.8% (13/166) in Gao'an city, 3.7% (4/108) in Xinyu city, and 0.0% (0/60) in Ji'an city. The differences of the prevalence rates by region, breed, and age groups were statistically significant. All positive PCR products of Cryptosporidium were successfully sequenced and identified as three Cryptosporidium species, namely Cryptosporidium bovis (1/556, 0.18%), Cryptosporidium ryanae (7/556, 1.3%), and Cryptosporidium andersoni (63/556, 11.3%). Furthermore, 36 C. andersoni isolates were successfully classified into three MLST (multilocus sequence typing) subtypes based on four genetic loci (MS1, MS2, MS3, and MS16). The predominant MLST subtype was A4, A4, A4, A1 (n = 30). These findings not only revealed the prevalence and predominant species of Cryptosporidium in cattle in Jiangxi province, but also provided a baseline for studying the genetic structure of C. andersoni, offering a novel resource for better understanding of the epidemiology of Cryptosporidium infection in cattle in Jiangxi province, southeastern China.

Parasitic diseases of equids in Iran (1931-2020): a literature review

Parasitic infections can cause many respiratory, digestive and other diseases and contribute to some performance conditions in equids. However, knowledge on the biodiversity of parasites of equids in Iran is still limited. The present review covers all the information about parasitic diseases of horses, donkeys, mules and wild asses in Iran published as articles in Iranian and international journals, dissertations and congress papers from 1931 to July 2020. Parasites so far described in Iranian equids include species of 9 genera of the Protozoa (Trypanosoma, Giardia, Eimeria, Klossiella, Cryptosporidium, Toxoplasma, Neospora, Theileria and Babesia), 50 helminth species from the digestive system (i.e., 2 trematodes, 3 cestodes and 37 nematodes) and from other organs (i.e., Schistosoma turkestanica, Echinococcus granulosus, Dictyocaulus arnfieldi, Parafilaria multipapillosa, Setaria equina and 3 Onchocerca spp.). Furthermore, 16 species of hard ticks, 3 mite species causing mange, 2 lice species, and larvae of 4 Gastrophilus species and Hippobosca equina have been reported from equids in Iran. Archeoparasitological findings in coprolites of equids include Fasciola hepatica, Oxyuris equi, Anoplocephala spp. and intestinal strongyles. Parasitic diseases are important issues in terms of animal welfare, economics and public health; however, parasites and parasitic diseases of equines have not received adequate attention compared with ruminants and camels in Iran. The present review highlights the knowledge gaps related to equines about the presence, species, genotypes and subtypes of Neospora hughesi, Sarcocystis spp., Trichinella spp., Cryptosporidium spp., Giardia duodenalis, Blastocystis and microsporidia. Identification of ticks vectoring pathogenic parasites, bacteria and viruses has received little attention, too. The efficacy of common horse wormers also needs to be evaluated systematically.

Cryptosporidium infections in sheep farms from Italy

Cryptosporidiosis is recognized as being a significant cause of gastrointestinal illness due to its wide range of vertebrate hosts, including humans. Infection with Cryptosporidium spp. is especially common in young domestic ruminants (calves, lambs and goat kids) and has been associated with economic losses worldwide. In contrast to cattle, to date, detailed studies on Cryptosporidium infections in sheep from Europe are still limited; thus, their importance as reservoirs of Cryptosporidium species with implications on animal and public health still needs to be clarified. This study evaluates the prevalence and zoonotic potential of Cryptosporidium spp. in sheep farms in Italy. A total of 915 individual faecal samples divided into three different animal categories were collected from 61 sheep farms. Each sample was examined by microscopy of faecal smears stained by modified Ziehl-Neelsen and by biomolecular techniques. Cryptosporidium oocysts were detected in 10.1% of the animals examined and in 34.4% of the farms. The prevalence of Cryptosporidium spp. was significantly higher (χ² = 51.854; P < 0.001) in diarrhoeic samples than in pasty or normal faeces. Genotype analyses showed the presence of two Cryptosporidium species: C. parvum and C. ubiquitum. Subtyping analysis of C. parvum isolates revealed the presence of subtypes IIa15G2R1 and IIdA20G1 and of subtype XIIa for C. ubiquitum. These findings have public health implications since both Cryptosporidium species identified are considered zoonotic, and C. parvum is the second-most common Cryptosporidium species infecting humans. Our data reveal that lambs, especially those excreting diarrhoeic faeces, may be important reservoirs of Cryptosporidium. We also highlight the need to establish adequate control and monitoring programmes for the control of this infection in sheep farms primarily through coprological monitoring.

Cryptosporidiosis and Giardiasis in Buffaloes (Bubalus bubalis)

Cryptosporidium spp. and Giardia duodenalis infect the gastrointestinal tracts of animals and humans. Both parasite groups are distributed worldwide and cause significant economic losses in animal productivity. Infected hosts presenting with and without clinical manifestations can eliminate infective forms of these protozoa, which are particularly important to One Health. Compared to the published research on cattle, relatively few studies have examined the epidemiology of cryptosporidiosis and giardiasis in buffaloes. This short review describes the global occurrence of Cryptosporidium spp. and G. duodenalis in buffaloes, including the molecular techniques employed for the identification of species/assemblages and genotypes of these protozoa. Genetic analyses of isolates of G. duodenalis and Cryptosporidium spp. from various sources (environmental, animal, and human) have been performed to investigate their epidemiology. In buffaloes, the species Cryptosporidium parvum, Cryptosporidium ryanae, Cryptosporidium bovis, and Cryptosporidium suis-like have been characterized, as well as assemblages A and E of G. duodenalis. We demonstrate that buffaloes can be infected by species of Cryptosporidium spp. and G. duodenalis assemblages with zoonotic potential. Epidemiological studies that utilize molecular biology techniques represent an important resource for efforts to control and prevent the spread of these protozoans.

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.