An Update on Zoonotic Cryptosporidium Species and Genotypes in Humans

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.

Enterocytozoon bieneusi and Cryptosporidium bat genotype XXI and bat genotype XXII in fruit bats (Rousettus leschenaultii) inhabiting a tropical park in Hainan Province, China

Bats stand as one of the most diverse groups in the animal kingdom and are key players in the global transmission of emerging pathogens. However, their role in transmitting Enterocytozoon bieneusi and Cryptosporidium spp. remains unclear. This study aimed to evaluate the occurrence and genetic diversity of the two pathogens in fruit bats (Rousettus leschenaultii) in Hainan, China. Ten fresh fecal specimens of fruit bats were collected from Wanlvyuan Gardens, Haikou, China. The fecal samples were tested for E. bieneusi and Cryptosporidium spp. using Polymerase Chain Reaction (PCR) analysis and sequencing the internal transcribed spacer (ITS) region and partial small subunit of ribosomal RNA (SSU rRNA) gene, respectively. Genetic heterogeneity across Cryptosporidium spp. isolates was assessed by sequencing 4 microsatellite/minisatellite loci (MS1, MS2, MS3, and MS16). The findings showed that out of the ten specimens analyzed, 2 (20 %) and seven (70.0 %) were tested positive for E. bieneusi and Cryptosporidium spp., respectively. DNA sequence analysis revealed the presence of two novel Cryptosporidium genotypes with 94.4 to 98.6 % sequence similarity to C. andersoni, named as Cryptosporidium bat-genotype-XXI and bat-genotype-XXII. Three novel sequences of MS1, MS2 and MS16 loci identified here had 95.4 to 96.9 % similarity to the known sequences, which were deposited in the GenBank. Two genotypes of E. bieneusi were identified, including a novel genotype named HNB-I and a zoonotic genotype PigEbITS7. The discovery of these novel sequences provides meaningful data for epidemiological studies of the both pathogens. Meanwhile our results are also presented that the fruit bats infected with E. bieneusi, but not with Cryptosporidium, should be considered potential public health threats.

Enteric parasites Cyclospora cayetanensis and Cryptosporidium hominis in domestic and wildlife animals in Ghana

BACKGROUND

Enteric parasitic infections remain a major public health problem globally. Cryptosporidium spp., Cyclospora spp. and Giardia spp. are parasites that cause diarrhea in the general populations of both developed and developing countries. Information from molecular genetic studies on the speciation of these parasites and on the role of animals as vectors in disease transmission is lacking in Ghana. This study therefore investigated these diarrhea-causing parasites in humans, domestic rats and wildlife animals in Ghana using molecular tools.

METHODS

Fecal samples were collected from asymptomatic school children aged 9-12 years living around the Shai Hills Resource Reserve (tourist site), from wildlife (zebras, kobs, baboons, ostriches, bush rats and bush bucks) at the same site, from warthogs at the Mole National Park (tourist site) and from rats at the Madina Market (a popular vegetable market in Accra, Ghana. The 18S rRNA gene (18S rRNA) and 60-kDa glycoprotein gene (gp60) for Cryptosporidium spp., the glutamate dehydrogenase gene (gdh) for Giardia spp. and the 18S rDNA for Cyclospora spp. were analyzed in all samples by PCR and Sanger sequencing as markers of speciation and genetic diversity.

RESULTS

The parasite species identified in the fecal samples collected from humans and animals included the Cryptosporidium species C. hominis, C. muris, C. parvum, C. tyzzeri, C. meleagridis and C. andersoni; the Cyclopora species C. cayetanensis; and the Gardia species, G. lamblia and G. muris. For Cryptosporidium, the presence of the gp60 gene confirmed the finding of C. parvum (41%, 35/85 samples) and C. hominis (29%, 27/85 samples) in animal samples. Cyclospora cayetanensis was found in animal samples for the first time in Ghana. Only one human sample (5%, 1/20) but the majority of animal samples (58%, 51/88) had all three parasite species in the samples tested.

CONCLUSIONS

Based on these results of fecal sample testing for parasites, we conclude that animals and human share species of the three genera (Cryptosporidium, Cyclospora, Giardia), with the parasitic species mostly found in animals also found in human samples, and vice-versa. The presence of enteric parasites as mixed infections in asymptomatic humans and animal species indicates that they are reservoirs of infections. This is the first study to report the presence of C. cayetanensis and C. hominis in animals from Ghana. Our findings highlight the need for a detailed description of these parasites using high-throughput genetic tools to further understand these parasites and the neglected tropical diseases they cause in Ghana where such information is scanty.

Cultivation, cryopreservation, and transcriptomic studies of host-adapted Cryptosporidium parvum and Cryptosporidium hominis using enteroids

Cryptosporidium hominis and Cryptosporidium parvum are major causes of severe diarrhea. Comparative studies of them are hampered by the lack of effective cultivation and cryopreservation methods, especially for C. hominis. Here, we describe adapted murine enteroids for the cultivation and complete development of host-adapted C. parvum and C. hominis subtypes, producing oocysts infectious to mice. Using the system, we developed a cryopreservation method for Cryptosporidium isolates. In comparative RNA-seq analyses of C. hominis cultures, the enteroid system generated significantly more host and pathogen responses than the conventional HCT-8 cell system. In particular, the infection was shown to upregulate PI3K-Akt, Ras, TNF, NF-κB, IL-17, MAPK, and innate immunity signaling pathways and downregulate host cell metabolism, and had significantly higher expression of parasite genes involved in oocyst formation. Therefore, the enteroid system provides a valuable tool for comparative studies of the biology of divergent Cryptosporidium species and isolates.

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.

Rabbits as reservoirs: An updated perspective of the zoonotic risk from Cryptosporidium and Giardia

Rabbits are highly abundant in many countries and can serve as reservoirs of diseases for a diversity of pathogens including the enteric protozoan parasites, Cryptosporidium and Giardia. Both parasites shed environmentally robust environmental stages (oo/cysts) and have been responsible for numerous waterborne outbreaks of diseases. Cryptosporidium hominis and C. parvum are responsible for most infections in humans, while Giardia duodenalis assemblages A and B, cause most human cases of giardiasis. Cryptosporidium cuniculus, the dominant species infecting rabbits, is the only spceies other than C. hominis and C. parvum to have caused a waterborne outbreak of gastritis, which occurred in the United Kingdom in 2008. This review examines the prevalence of Cryptosporidium and Giardia species in rabbits to better understand the public health risks of contamination of water sources with Cryptosporidium and Giardia oo/cysts from rabbits. Despite the abundance of C. cuniculus in rabbits, reports in humans are relatively rare, with the exception of the United Kingdom and New Zealand, and reports of C. cuniculus in humans from the United Kingdom have declined substantially since the 2008 outbreak. Subtyping of C. cuniculus has supported the potential for zoonotic transmission. Relatively few studies have been conducted on Giardia, but assemblage B dominates. However, improved typing methods are required to better understand the transmission dynamics of Giardia assemblages in rabbits. Similarly, it is not well understood if pet rabbits or contaminated water are the main source of C. cuniculus infections in humans. Well-planned studies using high-resolution typing tools are required to understand the transmission dynamics better and quantify the public health risk of Cryptosporidium and Giardia from rabbits.

Molecular characterization and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in humans and domestic animals in Heilongjiang Province, China

BACKGROUND

Cryptosporidiosis and giardiasis are significant parasitic diseases shared between humans and domestic animals. Due to the close contact between humans and domestic animals in rural areas, it is important to consider the potential transmission of zoonotic parasites from infected domestic animals to humans. This investigation aimed to determine the prevalence and molecular characteristics of Cryptosporidium spp. and Giardia duodenalis in domestic animals and villagers.

METHODS

A total of 116 fecal samples from villagers and 686 fecal samples from domestic animals in Heilongjiang Province, China, were analyzed for two parasites using nested polymerase chain reaction (PCR) targeting various genetic loci and DNA sequence analysis of the PCR products.

RESULTS

By sequence analysis of the SSU rRNA gene, the prevalence of Cryptosporidium in humans was 0.9% (1/116), with one species of C. parvum (n = 1) detected; among domestic animals, the prevalence was 2.6% (18/686), with five species identified: C. suis (n = 7) and C. scrofarum (n = 7) in pigs, C. meleagridis (n = 1) in chickens, C. andersoni (n = 1) in cattle, and C. canis (n = 2) in foxes. C. parvum and C. canis were further subtyped as IIdA19G1 and XXa4 on the basis of gp60 gene. Regarding G. duodenalis, based on the SSU rRNA, bg, gdh, and tpi genes, the prevalence in domestic animals was 5.1% (31/608), with three assemblages identified: A (n = 1) in pigs, D (n = 1) in foxes, and E (n = 27) in geese, cattle, pigs, ducks, and sheep, along with mixed infection of A + E (n = 1) in one pig and B + E (n = 1) in one sheep. No G. duodenalis was detected in humans (0/116).

CONCLUSIONS

The present results show that no overlap of subtypes between animals and villagers was found in Cryptosporidium spp. and G. duodenalis, indicating a minor role of domestic animals in infecting humans in this population. However, the presence of zoonotic protozoa in domestic animals highlights the need for special attention to high-risk individuals during close contact with domestic animals.

Prevalence of Cryptosporidium spp. in Sheep and Goats in Jiangsu, China

Sheep and goats serve as crucial hosts for Cryptosporidium spp. and are primarily responsible for its transmission via the fecal-oral route. This can result in symptoms such as lamb weight loss, diarrhea, and even fatalities, leading to significant economic losses. Currently, there is a lack of scholarly research investigating the prevalence of Cryptosporidium spp. infection in sheep and goats specifically within Jiangsu province. This study collected fecal samples from sheep and goats, extracted their DNA, amplified target bands using nested PCR, sequenced the DNA, constructed a phylogenetic tree, and identified the genetic genotype. In total, 3 positive samples were identified out of 398 samples. Furthermore, the gene sequences of these samples exhibited significant homology with C. xiaoi in GenBank. The phylogenetic analysis revealed that the Cryptosporidium spp. parasites under investigation are phylogenetically related to C. xiaoi. Conducting epidemiological investigations and accurately identifying the species of Cryptosporidium spp. is of utmost importance not only for the mutton sheep farming industry in Jiangsu but also for the proactive safeguarding of human health.

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.

Comparative genomics analysis reveals sequence characteristics potentially related to host preference in Cryptosporidium xiaoi

Cryptosporidium spp. are important diarrhea-associated pathogens in humans and livestock. Among the known species, Cryptosporidium xiaoi, which causes cryptosporidiosis in sheep and goats, was previously recognized as a genotype of the bovine-specific Cryptosporidium bovis based on their high sequence identity in the ssrRNA gene. However, the lack of genomic data has limited characterization of the genetic differences between the two closely related species. In this study, we sequenced the genomes of two C. xiaoi isolates and performed comparative genomic analysis to identify the sequence uniqueness of this ovine-adapted species compared with other Cryptosporidium spp. Our results showed that C. xiaoi is genetically related to C. bovis as shown by their 95.8% genomic identity and similar gene content. Consistent with this, both C. xiaoi and C. bovis appear to have fewer genes encoding mitochondrial metabolic enzymes and invasion-related protein families. However, they appear to possess several species-specific genes. Further analysis indicates that the sequence differences between these two Cryptosporidium spp. are mainly in 24 highly polymorphic genes, half of which are located in the subtelomeric regions. Some of these subtelomeric genes encode secretory proteins that have undergone positive selection. In addition, the genomes of two C. xiaoi isolates, identified as subtypes XXIIIf and XXIIIh, share 99.9% nucleotide sequence identity, with six highly divergent genes encoding putative secretory proteins. Therefore, these species-specific genes and sequence polymorphism in subtelomeric genes probably contribute to the different host preference of C. xiaoi and C. bovis.

The risk of wild birds contaminating source water with zoonotic Cryptosporidium and Giardia is probably overestimated

Cryptosporidium and Giardia are important waterborne protozoan parasites that are resistant to disinfectants commonly used for drinking water. Wild birds, especially wild migratory birds, are often implicated in the contamination of source and wastewater with zoonotic diseases, due to their abundance near water and in urban areas and their ability to spread enteric pathogens over long distances. This review summarises the diversity of Cryptosporidium and Giardia in birds, with a focus on zoonotic species, particularly in wild and migratory birds, which is critical for understanding zoonotic risks. The analysis revealed that both avian-adapted and zoonotic Cryptosporidium species have been identified in birds but that avian-adapted Cryptosporidium species dominate in wild migratory birds. Few studies have examined Giardia species and assemblages in birds, but the non-zoonotic Giardia psittaci and Giardia ardeae are the most commonly reported species. The identification of zoonotic Cryptosporidium and Giardia in birds, particularly C. parvum and G. duodenalis assemblages A and B in wild migratory birds, is likely due to mechanical carriage or spillback from birds co-grazing pastures contaminated with C. parvum from livestock. Therefore, the role of wild migratory birds in the transmission of zoonotic Cryptosporidium and Giardia to source water is likely overestimated. To address knowledge gaps, it is important to conduct more extensive studies on the prevalence of Cryptosporidium and Giardia in a broader range of migratory wild birds. There is also a need to investigate the extent to which zoonotic infections with C. hominis/C. parvum and G. duodenalis assemblages A and B are mechanical and/or transient, and to assess the load and viability of zoonotic oo/cysts shed in avian faeces. Understanding the contribution of birds to zoonoses is essential for effective disease surveillance, prevention, and control.

Detection of zoonotic Cryptosporidium spp. in small wild rodents using amplicon-based next-generation sequencing

Rodents may serve as reservoirs of zoonotic species of Cryptosporidium; however, data from molecular surveys in support of this hypothesis are still scarce. In this study, we screened faeces and rectal content from murid and cricetid rodents (N = 58) caught around three farms in Zealand, Denmark, for Cryptosporidium spp. by amplicon-based next-generation sequencing (NGS) of ribosomal genes. Selected samples were further examined using nested conventional PCR targeting SSU rRNA, gp60, and actin genes. Cryptosporidium-specific DNA was identified in 40/58 (69%) samples, and in 12 (30%) of the 40 positive animals, mixed cryptosporidial infections were observed. Cryptosporidium ditrichi was the species most commonly identified, found in 28 (48%) of the animals. Cryptosporidium parvum was identified in 4 (7%) of the animals, all of which were co-infected with C. ditrichi. The present study is the first to utilize NGS-based screening for Cryptosporidium species in wild rodents. Moreover, it is the first study to provide molecular data on Cryptosporidium in rodents sampled in Denmark and to detect DNA of C. ditrichi in Mus musculus, Myodes glareolus, and Microtus agrestis. The NGS approach was successfully applied to yield new knowledge, and the results showed that zoonotic species of Cryptosporidium are common in murid and cricetid rodents in Zealand, Denmark.

Cryptosporidium species and subtypes identified in human domestic cases through the national microbiological surveillance programme in Sweden from 2018 to 2022

BACKGROUND

The intestinal protozoan parasite Cryptosporidium is an important cause of diarrheal disease worldwide. A national microbiological surveillance programme was implemented in Sweden in 2018 in order to increase knowledge of the molecular epidemiology of human cryptosporidiosis to better understand transmission patterns and potential zoonotic sources. This article summarises the results of the first five years of the surveillance programme.

METHODS

Cryptosporidium-positive faecal and DNA samples from domestically acquired infections were collected from clinical microbiological laboratories in Sweden. Species and subtype determination was performed using 60 kDa glycoprotein and/or small subunit ribosomal RNA gene analysis.

RESULTS

Between 2018 and 2022, 1654 samples were analysed and 11 different species were identified: C. parvum (n = 1412), C. mortiferum (n = 59), C. hominis (n = 56), C. erinacei (n = 11), C. cuniculus (n = 5), C. meleagridis (n = 3), C. equi (n = 2), C. ubiquitum (n = 2), and one each of C. canis, C. ditrichi and C. felis. Subtyping revealed seven subtype families of C. parvum (new subtype families IIy and IIz) and 69 different subtypes (11 new subtypes). The most common C. parvum subtypes were IIdA22G1c, IIdA24G1, IIdA15G2R1 and IIaA16G1R1b. For C. hominis, four different subtype families and nine different subtypes (two new subtypes) were identified. For additional species, two new subtype families (IIIk and VId) and nine new subtypes were identified. All successfully subtyped C. mortiferum cases were subtype XIVaA20G2T1, confirming previous findings in Sweden. Several outbreaks were identified of which the majority were foodborne and a few were due to direct contact with infected animals.

CONCLUSION

Infection with C. parvum is the leading cause of human cryptosporidiosis acquired in Sweden, where more than 90% of domestic cases are caused by this zoonotic species and only a small proportion of cases are due to infection with other species. The rodent-associated C. mortiferum is considered an emerging zoonotic species in Sweden and the number of domestically acquired human cases has surpassed that of infection with C. hominis. A high diversity of species and subtypes, as well as diversity within the same subtype, was detected. Also, cryptosporidiosis appears to affect adults to a great extent in Sweden.

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.

A Thorny Tale of Parasites: Screening for Enteric Protozoan Parasites in Hedgehogs from Portugal

Enteric protozoan parasites, such as Blastocystis sp., Balantioides coli, Cryptosporidium spp., and Giardia duodenalis, may have implications for both animal and human health.Transmitted through the fecal-oral route, these parasites cause symptoms such as diarrhea, abdominal pain, and weight loss. This study investigated the presence of these enteric protozoan parasites and genetically characterized them in hedgehogs from Portugal. A total of 110 hedgehog stool samples were collected. Molecular detection methods showed an overall occurrence of protozoa in 1.82% (2/110 95% CI: 0.22-6.41) of hedgehogs, with Blastocystis being found in one hedgehog and Cryptosporidium being found in another. No evidence for the presence of B. coli or G. duodenalis was found. This study suggests that there is a need to stay aware of hedgehogs as potential hosts of enteric protozoa. Ongoing research and surveillance efforts are recommended to explore practical prevention and control strategies. The results contribute to the limited knowledge of these parasites in Portuguese hedgehog populations and underscore their potential relevance to both veterinary and public health.

Study on genetic characteristics of Cryptosporidium isolates and first report of C. parvum IIdA24G2 subtype in dairy cattle in China

Cryptosporidium is an important gastrointestinal parasite that can cause mild to severe diarrhea in various vertebrates, including humans and domestic animals. Infection is prevalent in dairy cattle, particularly calves, resulting in diarrhea and increased mortality with significant production losses. However, the prevalence and identity of Cryptosporidium spp. in cattle in Heilongjiang Province is still poorly known. Our study aimed to investigate the prevalence and species and subtype distribution of Cryptosporidium in cattle in the region. In addition, we evaluated the zoonotic potential of Cryptosporidium isolates and assessed possible transmission routes and health effects of this organism. We collected 909 fecal samples from five different farms in Heilongjiang Province between August and September 2022. The samples underwent Cryptosporidium detection by nested PCR and small subunit (SSU) rRNA gene sequence analysis. Four Cryptosporidium species were identified, including C. parvum, C. bovis, C. ryanae, and C. andersoni, with an overall prevalence of 4.4% (40/909). Based on sequence analysis of the 60 kDa glycoprotein gene of C. parvum and C. bovis, three subtypes of C. parvum were identified, namely two previously known subtypes (IIdA19G1 and IIdA20G1), and one novel subtype (IIdA24G2). Two distinct subtype families were identified in C. bovis (XXVId and XXVIe). The high diversity of Cryptosporidium in dairy cattle and the emergence of a novel subtype of C. parvum in Heilongjiang Province suggest that dairy cattle may serve as a significant source of zoonotic cryptosporidiosis infection in this region.

Genetic crosses within and between species of Cryptosporidium

Parasites and their hosts are engaged in reciprocal coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host specificity, but genomic reassortment between different strains can enable parasites to jump host barriers and conquer new niches. In the apicomplexan parasite Cryptosporidium, genetic exchange has been hypothesized to play a prominent role in adaptation to humans. The sexual lifecycle of the parasite provides a potential mechanism for such exchange; however, the boundaries of Cryptosporidium sex are currently undefined. To explore this experimentally, we established a model for genetic crosses. Drug resistance was engineered using a mutated phenylalanyl tRNA synthetase gene and marking strains with this and the previously used Neo transgene enabled selection of recombinant progeny. This is highly efficient, and genomic recombination is evident and can be continuously monitored in real time by drug resistance, flow cytometry, and PCR mapping. Using this approach, multiple loci can now be modified with ease. We demonstrate that essential genes can be ablated by crossing a Cre recombinase driver strain with floxed strains. We further find that genetic crosses are also feasible between species. Crossing Cryptosporidium parvum, a parasite of cattle and humans, and Cryptosporidium tyzzeri a mouse parasite resulted in progeny with a recombinant genome derived from both species that continues to vigorously replicate sexually. These experiments have important fundamental and translational implications for the evolution of Cryptosporidium and open the door to reverse- and forward-genetic analysis of parasite biology and host specificity.

Molecular Characterization of Giardia intestinalis and Cryptosporidium spp. Detected in Humans in Ağrı, Türkiye

Background

We aimed to determine the prevalence of Giardia intestinalis and Cryptosporidium spp. in patients who admitted hospital with diarrhea and to gain information about the transmission of these parasites in Ağrı, Türkiye.

Methods

This study included 184 patients who applied to Ağrı-Diyadin State Hospital, Türkiye in 2022. The immunochromatographic card test was used for detection of the G. intestinalis and Cryptosporidium spp. Nested PCR-RFLP analysis of the COWP gene and sequence analysis of the gp60 gene were used to genotype and subtype Cryptosporidium spp., whereas Nested PCR and sequence analyses of β-giardin gene were used genotype G. intestinalis.

Results

Of the 184 stool specimens examined, 12 (14.29%) and 7 (3.80%) were positive for G. intestinalis and Cryptosporidium spp., respectively. The Cryptosporidium species were identified as C. parvum belonging to the IId sub-type family. The G. intestinalis were identified assemblages A.

Conclusion

Assemblage A, which is associated with diarrhea, is responsible for giardiasis and C. parvum IId subtype, often found in sheep, goats and cattle, is responsible for cryptosporidiosis in Ağrı, Türkiye.

Molecular characterization of Cryptosporidium in ruminants and observation of natural infection by Cryptosporidium andersoni in sheep from Paraná, Brazil

The aim of this study was to identify Cryptosporidium species found in cattle and sheep in Paraná, southern region of Brazil. Individual fecal samples from 458 bovines and 101 sheep were submitted for molecular analysis by PCR and nested PCR using specific primers for sequences of the 18S ribosomal unit (rRNA). Positive samples were analyzed using restriction fragment length polymorphism (RFLP), followed by genetic sequencing for species confirmation. The occurrence of Cryptosporidium was 11.27% (63/559). The highest occurrence was detected in lambs (12/59, 20.33%). From the 63 positive samples, it was possible to identify the species in 58 of them by RFLP and genetic sequencing. Five species of Cryptosporidium were identified: Cryptosporidium andersoni, Cryptosporidium bovis, Cryptosporidium ryanae, Cryptosporidium xiaoi, and Cryptosporidium parvum. The most prevalent species was C. andersoni (41.38%) and the least predominant was C. parvum (10.34%). The most abundant species of Cryptosporidium in dairy calves were C. andersoni (11/25) and C. ryanae (6/25). Of the 17 positive sheep, nine (52.94%) were infected with C. andersoni. This finding is the first report on the occurrence of C. andersoni in naturally infected sheep in Brazil and the first observation of a high absolute occurrence of this Cryptosporidium species in sheep.

Molecular detection and characterization of Giardia spp., Cryptosporidium spp., and Blastocystis in captive wild animals rescued from central Colombia

Cryptosporidium, Giardia, and Blastocystis are significant causes of diarrhea worldwide. However, studies on their prevalence in wild animals are limited, compared to humans and domestic animals. In this study, we collected 23 stool samples from captive wild rescued animals in Boyacá, Colombia. Using conventional PCR, we detected Cryptosporidium spp., Giardia spp., and Blastocystis in over half of the samples (69.6%). Cryptosporidium spp. (43.5%) were the most commonly found, followed by Giardia spp. (39.1%) and Blastocystis (13.0%). Co-infections involving these parasites were also observed. Subsequent genotyping revealed Cryptosporidium canis and Cryptosporidium ryanae as the predominant species. These findings contribute valuable information about the ecoepidemiology of intestinal parasites in Colombian wild animals.

Evidence of the Zoonotic Transmission of Cryptosporidium among Children and Pets

We investigated the zoonotic transmission of Cryptosporidium among the children (n = 188), dogs (n = 133), and cats (n = 55) living in 188 households. Fecal samples were examined using ELISA and confirmed via nested PCR. Coproantigens oocysts were detected in 3.7% of children, 8.3% of dogs, and 5.5% of cats. We found strong evidence of two cases of the zoonotic transmission of Cryptosporidium canis between children and dogs. Furthermore, four children and their respective pets (one dog and three cats) were infected with Cryptosporidium parvum, but we cannot exclude the hypotheses that the oocysts were transmitted from children to animals or that both hosts were infected by a shared source, such as contaminated water or food. The presence of an infected animal elevated the risk of zoonotic transmission by 129.7-fold (95% CI: 13.92-1209.68). Furthermore, sharing a bed with pets was identified as a risk factor for infection in children (OR: 9.9, 95% CI: 1.37-71.2). In conclusion, the zoonotic transmission of Cryptosporidium among children and pets cohabiting in the same household may be quite common, especially when infected animals lie or sleep on children's beds. These findings unequivocally highlight the public health concern surrounding C. canis.

Newly fabricated zinc oxide nanoparticles loaded materials for therapeutic nano delivery in experimental cryptosporidiosis

Cryptosporidiosis is a global health problem that threatens the lives of immunocompromised patients. This study targets to fabricate and investigate the efficiency of zinc oxide nanoparticles (ZnO-NPs), nitazoxanide (NTZ)-loaded ZnO-NPs, and Allium sativum (A. sativum)-loaded ZnO-NPs in treating cryptosporidiosis. Further FTIR, SEM, XRD, and zeta analysis were used for the characterization of ZnO-NPs and loaded materials. The morphology of loaded materials for ZnO-NPs changed into wrapped layers and well-distributed homogenous particles, which had a direct effect on the oocyst wall. The charge surface of all particles had a negative sign, which indicated well distribution into the parasite matrix. For anti-cryptosporidiosis efficiency, thirty immunosuppressed Cryptosporidium parvum-infected mice, classified into six groups, were sacrificed on the 21st day after infection with an evaluation of parasitological, histopathological, and oxidative markers. It was detected that the highest reduction percent of Cryptosporidium oocyst shedding was (81.5%) in NTZ, followed by (71.1%) in A. sativum-loaded ZnO-NPs-treated groups. Also, treatment with A. sativum and NTZ-loaded ZnO-NPs revealed remarkable amelioration of the intestinal, hepatic, and pulmonary histopathological lesions. Furthermore, they significantly produced an increase in GSH values and improved the changes in NO and MDA levels. In conclusion, this study is the first to report ZnO-NPs as an effective therapy for treating cryptosporidiosis, especially when combined with other treatments that enhance their antioxidant activity. It provides an economical and environment-friendly approach to novel delivery synthesis for antiparasitic applications.

Development of Nested Polymerase Chain Reaction with Novel Specific Primers for Detection of Tritrichomonas muris Infection in Laboratory Mice

A variety of rodent ceca are parasitized by Tritrichomonas muris (T. muris), a flagellated protozoan. To date, there are no ideal methods for the detection of T. muris infections in laboratory mice; thus, new molecular methodologies for its specific detection need to be developed. In this study, using staining and SEM, it was observed that T. muris has a pear-shaped body and contains three anterior flagella. A nested PCR system with novel specific primers was designed based on the conserved regions of the SSU rRNA gene of T. muris. The nested PCR system for T. muris showed good specificity and high sensitivity for at least 100 T. muris trophozoites/mL and 0.1 ng/μL of fecal genomic DNA, which means that 176 trophozoites per gram of mouse feces could be detected. When using this nested PCR system, the detection rate was 18.96% (58/306), which was higher than the detection rate of 14.05% (43/306) detected via smear microscopy in fecal samples from five mouse strains. The sensitivity and specificity of nested PCR in detecting T. muris was found to be 100%, and it demonstrated a 26% increase in diagnostic sensitivity compared to the smear microscopy method in the present study. In conclusion, the nested PCR developed with novel primers based on the SSU rRNA gene of T. muris has good accuracy, specificity, and sensitivity for the detection of T. muris infections in laboratory mice.

Rapid detection of Cryptosporidium spp. in diarrheic cattle feces by isothermal recombinase polymerase amplification assays

As a zoonotic parasite, Cryptosporidium spp. could cause severe diarrhea mainly in calves and children globally. Monitoring and prevention of Cryptosporidium spp.'s prevalence is of great significance in both economy and public health aspects. In this study, specific primers and probes were designed within the conserved region of 18S rRNA gene for Cryptosporidium spp. and recombinase polymerase amplification assays based on the fluorescence monitoring (real-time RPA) as well as combined with a lateral flow strip (LFS RPA) were developed. Both of the two RPA assays allowed the exponential amplification of the target fragment within 20 min. After incubation on a metal bath at 42 °C, the LFS RPA results were displayed on the lateral flow strip within 5 min while real-time RPA allowed the real-time observation of the results in Genie III at 39 °C. The RPA assays showed high specificity for Cryptosporidium spp. without any cross-reaction with other tested pathogens causing diarrhea in cattle. With the recombinant plasmid DNA containing the 18S rRNA gene of Cryptosporidium spp. serving as a template, the limit of detection for real-time RPA and LFS RPA assays were 14.6 and 12.7 copies/reaction, respectively. Moreover, the RPA assays were validated by testing diarrheic cattle fecal samples and compared with a real-time PCR. The positive ratio of Cryptosporidium spp. was 24.04 % (44/183) and 26.23 % (48/183) in both RPA assays and real-time PCR assay, respectively, and the kappa coefficient value was 0.942. The diagnostic specificity and diagnostic sensitivity of both RPA assays were 100 % and 91.67 %, respectively. Forty-one of 48 positive samples were successfully sequenced and four Cryptosporidium species were detected, including C. parvum (n = 20), C. andersoni (n = 17), C. bovis (n = 3) and C. ryanae (n = 1). The developed RPA assays are easy to operate and faster to obtain the detection results, and they are suiting for the point-of-care detection and facilitating the prevention and control of Cryptosporidium spp. infections.

Comparison of four commercial immunomagnetic separation kits for the detection of Cryptosporidium

Cryptosporidium spp. are protozoan parasites of significant health importance found in environmental waters globally. Four commercially available Cryptosporidium-specific immunomagnetic separation (IMS) kits used in various water sample matrices were analysed and compared. Beads were characterised by flow cytometry and tested for the recovery efficiencies for oocysts spiked into different matrices: river water sediment, clay sample, and filter backwash sample. Results showed that Dynabeads™ Cryptosporidium and Waterborne Crypto-Grab™ kits contained immunoglobulin IgM antibody-coated beads. In contrast, the BioPoint CryptoBead and the TCS Isolate kits contained immunoglobulin IgG antibody-coated beads. BioPoint CryptoBead was significantly coated with more antibodies and were able to capture oocysts more rapidly compared to the other beads. Recovery efficiencies of Dynabeads™, TCS Isolate® beads, and BioPoint CryptoBead ranged from 55 to 93% when tested against different sample matrices, with BioPoint CryptoBead resulting in the highest at 93% in reagent-grade water and Dynabeads™ at 55%, the lowest against clay samples. The Waterborne beads did not perform well on any samples, with recovery efficiencies ranging from 0 to 8%. Fluorescence microscopy analyses showed that both the IMS method and the sample matrix processed affect the quality of the membranes, with the cleanest samples for microscopy examination observed from BioPoint CryptoBead.

Molecular Identification and Genotyping of Cryptosporidium spp. and Blastocystis sp. in Cattle in Representative Areas of Shanxi Province, North China

Both Cryptosporidium spp. and Blastocystis sp. are common intestinal protozoa, which can cause zoonotic diseases and economic losses to livestock industry. To evaluate the prevalence and genetic population structure of Cryptosporidium spp. and Blastocystis sp. in beef and dairy cattle in Shanxi Province, north China, a total of 795 fecal samples were collected from beef and dairy cattle in three representative counties in Shanxi Province, and these fecal samples were examined using molecular approaches based on 18S small-subunit ribosomal RNA (SSU rRNA) of Cryptosporidium spp. and Blastocystis sp., respectively. Among 795 cattle fecal samples, 23 were detected as Cryptosporidium-positive and 103 were detected as Blastocystis-positive, and the overall prevalence of Cryptosporidium spp. and Blastocystis sp. in cattle in Shanxi Province was 2.9% and 13.0%, respectively. For Cryptosporidium spp., DNA sequence analysis indicated that all 23 positive samples were identified as C. andersoni. Furthermore, five known subtypes (ST1, ST10, ST14, ST21 and ST26) and three unknown subtypes of Blastocystis sp. were detected among 103 positive samples using DNA sequence analysis. This study reported the occurrence and prevalence of Cryptosporidium spp. and Blastocystis sp. in cattle in Shanxi Province for the first time, which extends the geographical distribution of these two zoonotic parasites and provides baseline data for the prevention and control of these two important zoonotic parasites in cattle in Shanxi Province.

Cryptosporidium parvum gp60 subtypes in diarrheic lambs and goat kids from Israel

Cryptosporidium parvum is the second-most prevalent Cryptosporidium species that infects humans worldwide. In European countries, it is the most prevalent species in sheep, suggesting that these animals are a source of zoonotic infection. Preweaned lambs and goats are particularly susceptible to infection by the parasite and may suffer from severe diarrhea whilst excreting large quantities of infectious oocysts. Fifty fecal samples from preweaned lambs and goats with diarrhea from 35 farms across Israel, found to be Cryptosporidium-positive by microscopy, were tested by PCR and sequence analyses to determine the infective species and subtypes. Cryptosporidium parvum DNA was detected in most samples from both lambs and goats (46/50). Cryptosporidium xiaoi DNA was detected in three samples from kids, with co-infection detected in a single sample. Eleven different C. parvum subtypes were found, 10 in lambs and 5 in goats. All subtypes were from the IIa and IId subtype families, with subtypes IIdA20G1 and IIaA15G2R1 being the most prevalent and widespread. These subtypes were previously found in calves and humans in Israel and are considered the most prevalent C. parvum subtypes in small ruminants globally. These results underline the zoonotic potential of C. parvum from small ruminants and the high subtype diversity compared to previous reports from other Middle Eastern countries. In addition, this is the first report of C. xiaoi in Israel.

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.

Genetic crosses within and between species of Cryptosporidium

Parasites and their hosts are engaged in rapid coevolution that balances competing mechanisms of virulence, resistance, and evasion. This often leads to host specificity, but genomic reassortment between different strains can enable parasites to jump host barriers and conquer new niches. In the apicomplexan parasite Cryptosporidium genetic exchange has been hypothesized to play a prominent role in adaptation to humans. The sexual lifecycle of the parasite provides a potential mechanism for such exchange; however, the boundaries of Cryptosporidium sex are currently undefined. To explore this experimentally, we established a model for genetic crosses. Drug resistance was engineered using a mutated phenylalanyl tRNA synthetase gene and marking strains with this and the previously used Neo transgene enabled selection of recombinant progeny. This is highly efficient, and genomic recombination is evident and can be continuously monitored in real time by drug resistance, flow cytometry, and PCR mapping. Using this approach multiple loci can now be modified with ease. We demonstrate that essential genes can be ablated by crossing a Cre recombinase driver strain with floxed strains. We further find that genetic crosses are also feasible between species. Crossing C. parvum, a parasite of cattle and humans, and C. tyzzeri a mouse parasite resulted in progeny with a recombinant genome derived from both species that continues to vigorously replicate sexually. These experiments have important fundamental and translational implications for the evolution of Cryptosporidium and open the door to reverse- and forward- genetic analysis of parasite biology and host specificity.

Molecular Detection and Epidemiology of Potentially Zoonotic Cryptosporidium spp. and Giardia duodenalis in Wild Boar (Sus scrofa) from Eastern Spain

The protozoans Giardia duodenalis and Cryptosporidium spp. are common causes of gastrointestinal disease in humans and animals. While both are commonly documented in domestic animals, few studies have analysed their presence in wildlife. To assess the prevalence of both parasites in wild boar (Sus scrofa) in the Valencian Community (eastern Spain), 498 wild boar faecal samples were collected from 2018 to 2022. Cryptosporidium spp. was detected by performing a nested PCR targeting a 578 bp sequence of the small subunit ribosomal RNA gene (SSU rRNA), followed by sequencing and phylogenetic analysis. For G. duodenalis, a qPCR amplifying a fragment of 62 bp from the SSU rRNA was employed. Positive samples were genotyped for glutamate dehydrogenase and β-giardin genes. Different epidemiological factors were considered potential modulating variables in the transmission of both parasites. G. duodenalis prevalence was 1.20%, while Cryptosporidium spp. prevalence reached 21.7%. Coinfection was observed in 0.2%. Genotyping of G. duodenalis isolates only detected genotype E. Two species of Cryptosporidium spp. were identified: Cryptosporidium scrofarum and Cryptosporidium suis. The results of this study demonstrate that the exposure to Cryptosporidium spp. in wild boars is high, particularly among young individuals belonging to the Typical Mediterranean climate. Moreover, the probability of infection is dependent on both the season and the density of wild boars. On the other side, exposure to G. duodenalis seems scarce and is influenced, in turn, by the climate. Both Cryptosporidium species detected in the present study have been reported in humans. Due to wild boar increasing in number and their colonisation of urban and peri-urban areas, this could represent an inherent health risk for the human population.

Biosensors as early warning detection systems for waterborne Cryptosporidium

Waterborne disease is a global health threat contributing to a high burden of diarrhoeal disease, and growing evidence indicates a prospective increase in incidence coinciding with the profound effects of climate change. A major causative agent of gastrointestinal disease is Cryptosporidium, a protozoan waterborne parasite identified in over 70 countries. Cryptosporidium is a cause of high disease morbidity in children and the immunocompromised with limited treatment options for patients at risk of severe illness. The hardy nature of the organism leads to its persistence in various water sources, with certain water treatment procedures proving inefficient for its complete removal. While diagnostic methods for Cryptosporidium are well-defined in the clinical sphere, detection of Cryptosporidium in water sources remains suboptimal due to low dispersion of organisms in large sample volumes, lengthy processing times and high costs of equipment and reagents. A need for improvement exists to identify the organism as an emerging threat in domestic water systems, and the technological advantages that biosensors offer over current analytical methods may provide a preventative approach to outbreaks of Cryptosporidium. Biosensors are innovative, versatile and adaptable analytical tools that could provide highly sensitive, rapid, on-site analysis needed for Cryptosporidium detection in low-resource settings.

Molecular characteristics and zoonotic potential of enteric protists in domestic dogs and cats in Egypt

Introduction

Domestic dogs and cats can be a source of human infection by a wide diversity of zoonotic pathogens including parasites. Genotyping and subtyping tools are useful in assessing the true public health relevance of canine and feline infections by these pathogens. This study investigated the occurrence, genetic diversity, and zoonotic potential of common diarrhea-causing enteric protist parasites in household dogs and cats in Egypt, a country where this information is particularly scarce.

Methods

In this prospective, cross-sectional study a total of 352 individual fecal samples were collected from dogs (n = 218) and cats (n = 134) in three Egyptian governorates (Dakahlia, Gharbeya, and Giza) during July-December 2021. Detection and identification of Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. were carried out by PCR and Sanger sequencing. Basic epidemiological variables (geographical origin, sex, age, and breed) were examined for association with occurrence of infection by enteric protists.

Results and discussion

The overall prevalence rates of Cryptosporidium spp. and G. duodenalis were 1.8% (95% CI: 0.5-4.6) and 38.5% (95% CI: 32.0-45.3), respectively, in dogs, and 6.0% (95% CI: 2.6-11.4) and 32.1% (95% CI: 24.3-40.7), respectively, in cats. All canine and feline fecal samples analyzed tested negative for E. bieneusi and Blastocystis sp. Dogs from Giza governorate and cats from Dakahlia governorate were at higher risk of infection by Cryptosporidium spp. (p = 0.0006) and G. duodenalis (p = 0.00001), respectively. Sequence analyses identified host-adapted Cryptosporidium canis (n = 4, one of them belonging to novel subtype XXe2) and G. duodenalis assemblages C (n = 1) and D (n = 3) in dogs. In cats the zoonotic C. parvum (n = 5) was more prevalent than host-adapted C. felis (n = 1). Household dogs had a limited (but not negligible) role as source of human giardiasis and cryptosporidiosis, but the unexpected high frequency of zoonotic C. parvum in domestic cats might be a public health concern. This is the first molecular-based description of Cryptosporidium spp. infections in cats in the African continent to date. Molecular epidemiological data provided here can assist health authorities and policy makers in designing and implementing effective campaigns to minimize the transmission of enteric protists in Egypt.

High subtelomeric GC content in the genome of a zoonotic Cryptosporidium species

Cryptosporidium canis is a zoonotic species causing cryptosporidiosis in humans in addition to its natural hosts dogs and other fur animals. To understand the genetic basis for host adaptation, we sequenced the genomes of C. canis from dogs, minks, and foxes and conducted a comparative genomics analysis. While the genomes of C. canis have similar gene contents and organisations, they (~41.0 %) and C. felis (39.6 %) have GC content much higher than other Cryptosporidium spp. (24.3-32.9 %) sequenced to date. The high GC content is mostly restricted to subtelomeric regions of the eight chromosomes. Most of these GC-balanced genes encode Cryptosporidium-specific proteins that have intrinsically disordered regions and are involved in host-parasite interactions. Natural selection appears to play a more important role in the evolution of codon usage in GC-balanced C. canis, and most of the GC-balanced genes have undergone positive selection. While the identity in whole genome sequences between the mink- and dog-derived isolates is 99.9 % (9365 SNVs), it is only 96.0 % (362 894 SNVs) between them and the fox-derived isolate. In agreement with this, the fox-derived isolate possesses more subtelomeric genes encoding invasion-related protein families. Therefore, the change in subtelomeric GC content appears to be responsible for the more GC-balanced C. canis genomes, and the fox-derived isolate could represent a new Cryptosporidium species.

Foodborne protozoan parasites in fresh mussels and oysters purchased at retail in Canada

Studies worldwide have reported the presence of protozoan parasites in a variety of commercial bivalve shellfish. The uptake of these parasites by shellfish occurs during filter feeding in faecally-contaminated waters. The objective of the present study was to determine the prevalence of Giardia, Cryptosporidium and Toxoplasma in fresh, live shellfish purchased in three Canadian provinces as part of the retail surveillance activities led by FoodNet Canada (Public Health Agency of Canada). Packages containing mussels (n = 253) or oysters (n = 130) were purchased at grocery stores in FoodNet Canada sentinel sites on a biweekly basis throughout 2018 and 2019, and shipped in coolers to Health Canada for testing. A small number of packages were not tested due to insufficient quantity or poor quality. Following DNA extraction from homogenized, pooled tissues, nested PCR and DNA sequencing were used to detect parasite-specific sequences. Epifluorescence microscopy was used to confirm the presence of intact cysts and oocysts in sequence-confirmed PCR-positive samples. Giardia duodenalis DNA was present in 2.4 % of 247 packages of mussels and 4.0 % of 125 packages of oysters, while Cryptosporidium parvum DNA was present in 5.3 % of 247 packages of mussels and 7.2 % of 125 packages of oysters. Toxoplasma gondii DNA was only found in mussels in 2018 (1.6 % of 249 packages). Parasite DNA was detected in shellfish purchased in all three Canadian provinces sampled, and there was no apparent seasonal variation in prevalence. While the present study did not test for viability, parasites are known to survive for long periods in the marine environment, and these findings suggest that there is a risk of infection, especially when shellfish are consumed raw.

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 characterization of Cryptosporidium and Giardia in environmental samples and faecal samples from biogas users in Bac Giang, Vietnam

Little is known about Cryptosporidium and Giardia in biogas waste and humans in Vietnam. There is a potential risk of infections during or after using the biogas system. The detected protozoan genotypes are zoonotic pathogens, and contamination of vegetables may relay through runoff to the surface waters and soil. The objective of this study was to understand the role of the environment in the epidemiology of human infections in Bac Giang province, Vietnam, with a focus on investigating the presence of Cryptosporidium spp. genotypes and Giardia assemblages among 239 environmental samples and 94 faecal samples of biogas users. PCR and sequencing analysis were used to identify the occurrence and genotypes of Cryptosporidium and Giardia in these samples. Results showed that 13/333 (3.9 %) and 9/333 (2.7 %) samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively. Characterization revealed the presence of Cryptosporidium scrofarum, C. suis, C. meleagridis, C. bailey and Giardia intestinalis assemblage A and E. C. scrofarum and Giardia assemblage E were identified for the first time in humans in Bac Giang. The current information from the above investigations will be valuable for protozoan source tracking and control interventions against Cryptosporidium and Giardia infection associated with biogas wastes in Vietnam.

Dendritic Cells and Cryptosporidium: From Recognition to Restriction

Host immune responses are required for the efficient control of cryptosporidiosis. Immunity against Cryptosporidium infection has been best studied in mice, where it is mediated by both innate and adaptive immune responses. Dendritic cells are the key link between innate and adaptive immunity and participate in the defense against Cryptosporidium infection. While the effector mechanism varies, both humans and mice rely on dendritic cells for sensing parasites and restricting infection. Recently, the use of mouse-adapted strains C. parvum and mouse-specific strain C. tyzzeri have provided tractable systems to study the role of dendritic cells in mice against this parasite. In this review, we provide an overview of recent advances in innate immunity acting during infection with Cryptosporidium with a major focus on the role of dendritic cells in the intestinal mucosa. Further work is required to understand the role of dendritic cells in the activation of T cells and to explore associated molecular mechanisms. The identification of Cryptosporidium antigen involved in the activation of Toll-like receptor signaling in dendritic cells during infection is also a matter of future study. The in-depth knowledge of immune responses in cryptosporidiosis will help develop targeted prophylactic and therapeutic interventions.

Cryptosporidium parvum and gp60 genotype prevalence in dairy calves worldwide: a systematic review and meta-analysis

Cryptosporidium is a significant zoonotic pathogen that often occurs in dairy cattle. We conducted a systematic review and meta-analysis of the prevalence of Cryptosporidium parvum infection in dairy calves worldwide to help improve global animal husbandry and public policy implementation. Published articles were obtained from PubMed and Web of Science from January 1, 2000 to December 31, 2021. The prevalence of C. parvum infection in dairy calves was estimated using a random effects model, and the sources of heterogeneity were explored using meta-regression. In total, 118 datasets were included in the final quantitative analysis. The results showed that the global prevalence of C. parvum in dairy calves was 21.9% (7755/42,890; 95% confidence interval: 19.9-23.9%). C. parvum infection was high in pre-weaned dairy calves (24.9%, 6706/29,753) and diarrhea dairy calves (33.6%, 1637/6077). In countries with low dairy stocking density (<10 cows/farm), the prevalence of C. parvum in dairy calves was also relatively low (15.2%, 1960/16,584). Three subtype families [IIa (72.2%, 2293/3177), IId (27.4%, 872/3177), and IIl (0.4%, 12/3177)] were detected in dairy calves globally from selected studies. C. parvum IIa was the dominant zoonotic subtype. In the IIa subtype family of C. parvum, the proportions of subtypes from high to low (top nine) were IIaA15G2R1 (32.4%, 742/2293), IIaA18G3R1 (11.8%, 271/2293), IIaA13G2R1 (8.2%, 187/2293), IIaA16G1R1 (6.4%, 147/2293), IIaA20G1R1 (3.5%, 81/2293), IIaA16G3R1 (3.4%, 78/2293), IIaA17G2R1 (2.7%, 62/2293), IIaA18G1R1 (2.5%, 58/2293), and IIaA15G1R1 (2.4%, 56/2293). In the IId subtype family of C. parvum, the proportions of subtypes (top four) were IIdA19G1 (36.0%, 314/872), IIdA15G1 (27.3%, 238/872), IIdA20G1 (16.2%, 141/872), and IIdA14G1 (13.0%, 113/872). Furthermore, IId is commonly found in China (771/872). The study results indicated that the IIa subtype family is globally prevalent, while IId is found in Asia, Europe, and Africa and IIl is only found in Europe. Diarrhea in dairy calves is associated with C. parvum infection and a significantly higher prevalence is observed in diarrheic calves. Age and stock density are two significant risk factors in the prevalence of C. parvum in dairy calves. The prevention and control of this zoonosis in dairy calves should receive greater attention, especially in regions with a high degree of intensive dairy farming.

Migrating Anatidae as Sources of Environmental Contamination with Zoonotic Giardia, Cryptosporidium, Cyclospora and Microsporidia

Giardia, Cryptosporidium, Cyclospora, and microsporidia are gastrointestinal pathogens that can cause various disease symptoms in both animals and humans. Numerous studies worldwide have confirmed the presence of these eukaryotic pathogens in nesting and migrating wild geese, ducks, and swans. Migration spreads these zoonotic enteric pathogens to distant locations, which could have public health implications. Soils and water bodies (lakes, ponds, rivers and wetlands) in urban and suburban areas have been shown to be vulnerable to contamination by waterfowl droppings. This review addresses the epidemiology of these enteric pathogens in wild migratory bird species (Anatidae) and some consequences of their spread in the environment. To date, both zoonotic pathogens and genotypes restricted to avian hosts have been found in faecal samples from 21 anatid species worldwide. One of the routes of infection for these zoonotic gastrointestinal micropathogens is the indirect route. For example, shared water bodies (e.g., for drinking or recreational purposes) previously contaminated by birds during the migratory season may facilitate infections of humans through water. However, it is unclear how much wild waterfowl contribute to the transmission of giardiasis, cryptosporidiosis, cyclosporosis, and microsporidiosis in many regions through contaminated environmental sources. Comprehensive epidemiological surveillance based on molecular data on gastrointestinal pathogens is crucial to take measures to control infections in the future.

Multilocus Sequence Typing as a Useful Tool for the Study of the Genetic Diversity and Population Structure of Cryptosporidium Spp

One of the most important aquatic parasites in industrialized countries, Cryptosporidium spp., is a major cause of diarrheal disease in humans and animals worldwide. The contingent evolution of cryptosporidia with hosts, host adaptation, and geographic variation contributed to the creation of species subtypes, thereby shaping their population genetic structures. Multilocus typing tools for population genetic characterizations of transmission dynamics and delineation of mechanisms for the emergence of virulent subtypes have played an important role in improving our understanding of the transmission of this parasite. However, to better understand the significance of different subtypes with clinical disease manifestations and transmission risks, a large number of samples and preferably from different geographical areas need to be analyzed. This review provides an analysis of genetic variation through multilocus sequence typing, provides an overview of subtypes, typing gene markers for Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium muris and Cryptosporidium andersoni genotypes and an overview of the hosts of these parasites.

Molecular identification and genetic characteristics of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in human immunodeficiency virus/acquired immunodeficiency syndrome patients in Shanghai, China

BACKGROUND

Opportunistic infections are a ubiquitous complication in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients. Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are common opportunistic intestinal pathogens in humans. In China, despite the number of HIV/AIDS patients being extremely large, only a few studies have investigated opportunistic infections caused by intestinal pathogens in this patient population. The aims of this study were to elucidate the occurrence and genetic characteristics of Cryptosporidium spp., G. duodenalis, and E. bieneusi in HIV/AIDS patients.

METHODS

We collected fecal specimens from 155 HIV/AIDS patients (one from each patient). All of the specimens were examined for the presence of the pathogens by genotyping using polymerase chain reaction and sequencing of the small subunit ribosomal RNA gene for Cryptosporidium spp.; the triosephosphate isomerase, β-giardin and glutamate dehydrogenase genes for G. duodenalis; and the internal transcribed spacer region of the rRNA gene for E. bieneusi. The Cryptosporidium-positive specimens were further subtyped by polymerase chain reacion and sequencing of the 60-kDa glycoprotein gene.

RESULTS

Six (3.9%), three (1.9%), and eight (5.2%) HIV/AIDS patients were positive for Cryptosporidium spp., G. duodenalis, and E. bieneusi, respectively. No statistical differences were observed in occurrence rate between the groups by gender, clinical symptom (diarrhea), and CD4⁺ cell count. Four Cryptosporidium species were identified: Cryptosporidium hominis (n = 2), Cryptosporidium parvum (n = 1), Cryptosporidium meleagridis (n = 1), and Cryptosporidium andersoni (n = 2). Furthermore, two C. hominis subtypes (IeA12G3T3 and IaA28R4) were detected. Three G. duodenalis-positive specimens were successfully amplified and sequenced at the triosephosphate isomerase and β-giardin loci, which led to the identification of assemblages C and B, respectively. Seven genotypes (D, Type IV, EbpC, Peru11, EbpD, A, and I) were identified in E. bieneusi-positive specimens.

CONCLUSIONS

Our findings should increase awareness of AIDS-related opportunistic intestinal pathogens, and indicate the need for routine examination in clinical practice for the detection of Cryptosporidium spp., G. duodenalis, and E. bieneusi. Homology analyses of the three intestinal pathogens at the nucleotide and/or amino acid levels indicated their zoonotic potential.

Detection of unusual Cryptosporidium parvum subtype in patients with gastrointestinal cancer in Egypt

While the importance of cryptosporidiosis in immunocompromised persons is well known, the prevalence of Cryptosporidium spp. in cancer patients is not clear. The current study was designed to assess the occurrence and genetic characteristics of Cryptosporidium spp. in patients with gastrointestinal (GI) cancer in Egypt. Stool samples were collected from 100 patients with GI malignancies and 20 healthy individuals without any GI manifestations (control group). They were screened by microscopy and the immunochromatographic RIDA®QUICK Cryptosporidium kit. Subtyping of Cryptosporidium spp. was conducted by sequence analysis of the glycoprotein 60 (gp60) locus. Sociodemographic, environmental data and information on GI symptoms, cancer types, and clinical treatment were obtained via a questionnaire. By microscopy and RIDA®QUICK, only 7% (7/100) of GI cancer patients were positive for Cryptosporidium, compared with 40% (40/100) by gp60 nPCR. No positives were obtained from the control group. Male sex (P = 0.02) and younger age (P = 0.004) were major Cryptosporidium risk factors for infection. The occurrence of Cryptosporidium was also significantly more frequent (P = 0.003) in watery stool samples. Sequence analysis of the gp60 amplicons (~ 400 bp) identified a novel C. parvum subtype with nine TCA repeats and eleven ACATCA repeats. A formal subtype designation could not be made due to the short sequence length. More studies should be conducted to verify the common occurrence of this unusual C. parvum subtype and establish its genetic identity.

Circulating in Wild Small Mammals from Portugal

Cryptosporidium spp. and Giardia spp. are important diarrhea-causing protozoan parasites worldwide that exhibit broad host ranges. Wild small mammals can harbor host-adapted and potentially zoonotic species of both parasites. The aim of this study was to investigate Cryptosporidium spp. and Giardia spp. in wild rodents and shrews in Portugal, focusing on the protist's occurrence and genetic diversity. Molecular screening by PCR at the small subunit (SSU) rRNA gene locus of 290 fecal samples from wood mice (Apodemus sylvaticus), southwestern water voles (Arvicola sapidus), Cabrera's voles (Microtus cabrerae), Lusitanian pine voles (Microtus lusitanicus), Algerian mice (Mus spretus) and greater white-toothed shrews (Crocidura russula) in Northeast Portugal revealed the low occurrence of Cryptosporidium spp. (1%) and high occurrence of Giardia spp. (32.8%). The analysis revealed that "species" was the only significant factor associated with the increasing probability of Giardia spp. infection, with the highest prevalence reported in southwestern water voles and Lusitanian pine voles. Cryptosporidium and Giardia species determination at the SSU rRNA gene locus revealed C. muris and G. microti as the only circulating species, respectively. Subtyping of the glutamate dehydrogenase (gdh) and beta-giardin (bg) genes provided evidence of the high genetic diversity within the G. microti clade. This study suggests that rodent-adapted G. microti occurs to a large extent in cricetid hosts and supports the limited role of wild rodents and shrews as natural sources of human infections in Northeast Portugal regarding the investigated parasites. Moreover, this is the first record of G. microti in southwestern water voles, Lusitanian pine voles, Algerian mice, wood mice and Cabrera's voles and C. muris in Cabrera's voles. Finally, this study improves the database of sequences relevant for the sequence typing of G. microti strains and provides new insights about the epidemiology of Giardia spp. and Cryptosporidium spp. in wild rodents and shrews, two parasite genera of high importance for public and animal health.

Molecular identification of Cryptosporidium, Giardia, and Blastocystis from stray and household cats and cat owners in Tehran, Iran

Cryptosporidiosis, giardiasis, and blastocystosis are among the most important parasitic diseases common between humans and cats. In addition, there are concerns about the possible transmission of zoonotic parasites from infected cats to humans. Hence, we investigated the molecular epidemiology of Cryptosporidium spp., Giardia duodenalis, and Blastocystis sp. in stray and household cats and cat owners. Our study was performed on 132, 33, and 33 fecal samples of stray and household cats, as well as cat owners in Tehran, Iran. Cryptosporidium spp. was identified using a nested PCR targeting the small subunit ribosomal RNA gene (SSU rRNA) and sequencing the internal amplified fragments. Furthermore, to perform multilocus genotyping of G. duodenalis, the ß-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes were amplified to assess the DNA of G. duodenalis in the fecal samples of cats and cat owners. In addition, Blastocystis was detected by targeting the SSU rRNA gene, and the subtypes of Blastocystis were determined via the sequencing of amplicons. Cryptosporidium felis and Cryptosporidium canis were detected in seven stray cats (5.3%) and one household cat (3%). The bg gene of G. duodenalis was amplified and successfully sequenced in two (1.5%) stray cats and revealed assemblages F and B of G. duodenalis. Sequencing and phylogenic analysis of SSU rRNA gene nucleotide sequences of Blastocystis detected ST5 and ST10 in stray cats (1.5%), ST1 in household cats (9.1%), and ST1, ST2, ST3, and ST7 in owners (30.3%). The low prevalence of Cryptosporidium, Giardia and Blastocystis in cats and the presence of species/assemblages/subtypes with limited zoonotic potential indicate that cats had a minor role in their owners' infection in the investigated population. However, the presence of zoonotic protozoa in cats suggests the necessity of special attention to high-risk individuals during close contact with cats. Therefore, it is recommended that veterinarians, physicians, and urban managers plan to prevent, control, or treat these parasites to help the urban community live healthily alongside cats.

Soft tissue tuberculosis detected by next-generation sequencing: A case report and review of literature

BACKGROUND

Soft tissue tuberculosis is rare and insidious, with most patients presenting with a localized enlarged mass or swelling, which may be factors associated with delayed diagnosis and treatment. In recent years, next-generation sequencing has rapidly evolved and has been successfully applied to numerous areas of basic and clinical research. A literature search revealed that the use of next-generation sequencing in the diagnosis of soft tissue tuberculosis has been rarely reported.

CASE SUMMARY

A 44-year-old man presented with recurrent swelling and ulcers on the left thigh. Magnetic resonance imaging suggested a soft tissue abscess. The lesion was surgically removed and tissue biopsy and culture were performed; however, no organism growth was detected. Finally, Mycobacterium tuberculosis was confirmed as the pathogen responsible for infection through next-generation sequencing analysis of the surgical specimen. The patient received a standardized anti-tuberculosis treatment and showed clinical improvement. We also performed a literature review on soft tissue tuberculosis using studies published in the past 10 years.

CONCLUSION

This case highlights the importance of next-generation sequencing for the early diagnosis of soft tissue tuberculosis, which can provide guidance for clinical treatment and improve prognosis.

The Presence of Potentially Pathogenic Protozoa in Lettuce (Lactuca sativa) Sold in Markets in the Central Peruvian Andes

Peru is currently one of the world’s leading culinary destinations, whose world-renowned cuisine uses vegetables, mainly lettuce, as frequent ingredients. Vegetable consumption is promoted worldwide as a part of a healthy diet. However, vegetables, more frequently lettuce, have been implicated as a vehicle of infection for several foodborne parasites. This study aimed to determine the presence of potentially pathogenic parasites in lettuce marketed in the Central Andes of Peru. A total of 75 lettuce samples were collected from the two largest wholesale markets and the main open-air market in Jauja province, in the central Peruvian Andes. The province of provenance (coast vs. highlands), lettuce variety (“curly-leaf”, “iceberg”, and “butter”), and type of market were recorded. The samples were microscopically examined for detection of parasitic life forms using standard parasitological methods including direct slide smear, Lugol’s iodine staining, and Modified Ziehl−Neelsen staining. The overall positivity of parasitic contamination in lettuces was 45.3% (CI 95%: 34−56.6%). Cryptosporidium spp., Isospora belli, Giardia lamblia, Balantidium coli, and Entamoeba spp. were detected in twenty-six (34.7%), six (8%), four (5.3%), two (2.7%), and two (2.7%) lettuces, respectively. I. belli was found in a significantly (p < 0.01) lower proportion in the “butter” variety, and significantly (p < 0.05) higher contamination with G. lamblia was found in lettuce sold at the open-air market. B. coli, G. lamblia, and E. histolytica/E. dispar/E. moshkovskii were detected only in lettuce from the highlands (Tarma province). This study provides important data for health authorities to develop food safety programs. This information is also of interest to the international community because of the increased visibility that Peru has gained as a tourist destination.

Point of care diagnostics for Cryptosporidium: new and emerging technologies

PURPOSE OF REVIEW

Although Cryptosporidium detection and typing techniques have improved dramatically in recent years, relatively little research has been conducted on point of care (POC) detection and typing tools. Therefore, the main purpose of the present review is to summarize and evaluate recent and emerging POC diagnostic methods for Cryptosporidium spp.

RECENT FINDINGS

Microscopy techniques such as light-emitting diode fluorescence microscopy with auramine-phenol staining (LED-AP), still have utility for (POC) diagnostics but require fluorescent microscopes and along with immunological-based techniques, suffer from lack of specificity and sensitivity. Molecular detection and typing tools offer higher sensitivity, specificity and speciation, but are currently too expensive for routine POC diagnostics. Isothermal amplification methods such as loop-mediated isothermal amplification (LAMP) or recombinase polymerase amplification (RPA) including a commercially available LAMP kit have been developed for Cryptosporidium but are prone to false positives. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas diagnostic technologies (CRISPRDx) have recently been combined with isothermal amplification to increase its specificity and sensitivity for detection and typing. Other emerging technologies including amplification-free CRISPR detection methods are currently being developed for Cryptosporidium using a smartphone to read the results.

SUMMARY

Many challenges are still exist in the development of POC diagnostics for Cryptosporidium. The ideal POC tool would be able to concentrate the pathogen prior to detection and typing, which is complicated and research in this area is still very limited. In the short-term, CRISPR-powered isothermal amplification lateral flow tools offer the best opportunity for POC Cryptosporidium species and subtype detection, with a fully integrated autonomous biosensor for the long-term goal.

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.

Cryptosporidium parvum regulates HCT-8 cell autophagy to facilitate survival via inhibiting miR-26a and promoting miR-30a expression

BACKGROUND

Cryptosporidium parvum is an important zoonotic parasite, which not only causes economic losses in animal husbandry but also harms human health. Due to the lack of effective measures for prevention and treatment, it is important to understand the pathogenesis and survival mechanism of C. parvum. Autophagy is an important mechanism of host cells against parasite infection through key regulatory factors such as microRNAs and MAPK pathways. However, the regulatory effect of C. parvum on autophagy has not been reported. Here, we demonstrated that C. parvum manipulated autophagy through host cellular miR-26a, miR-30a, ERK signaling and P38 signaling for parasite survival.

METHODS

The expression of Beclin1, p62, LC3, ERK and P38 was detected using western blotting in HCT-8 cells infected with C. parvum as well as treated with miR-26a-mimic, miR-30a-mimic, miR-26a-mimic or miR-30a-inhibitor post C. parvum infection. The qPCR was used to detect the expression of miR-26a and miR-30a and the number of C. parvum in HCT-8 cells. Besides, the accumulation of autophagosomes was examined using immunofluorescence.

RESULTS

The expression of Beclin1 and p62 was increased, whereas LC3 expression was increased initially at 0-8 h but decreased at 12 h and then increased again in C. parvum-infected cells. C. parvum inhibited miR-26a-mimic-induced miR-26a but promoted miR-30a-mimic-induced miR-30a expression. Suppressing miR-30a resulted in increased expression of LC3 and Beclin1. However, upregulation of miR-26a reduced ERK/P38 phosphorylation, and inhibiting ERK/P38 signaling promoted Beclin1 and LC3 while reducing p62 expression. Treatment with miR-26a-mimic, autophagy inducer or ERK/P38 signaling inhibitors reduced but treatment with autophagy inhibitor or miR-30a-mimic increased parasite number.

CONCLUSIONS

The study found that C. parvum could regulate autophagy by inhibiting miR-26a and promoting miR-30a expression to facilitate the proliferation of parasites. These results revealed a new mechanism for the interaction of C. parvum with host cells.