Genetic Diversity of Cryptosporidium in Bactrian Camels (Camelus bactrianus) in Xinjiang, Northwestern China

Genetic diversity of Cryptosporidium species from diarrhoeic ungulates in the United Arab Emirates

Cryptosporidiosis has previously been reported in animals, humans, and water sources in the United Arab Emirates (UAE). However, most reports were only to the genus level, or generically identified as cryptosporidiosis. We aimed to investigate the genetic diversity of Cryptosporidium species occurring in diarrhetic ungulates which were brought to the Central Veterinary Research Laboratory (CVRL) in Dubai. Using a combination of microscopic and molecular methods, we identified five species of Cryptosporidium occurring among ungulates in the UAE, namely C. parvum, C. hominis, C. xiaoi, C. meleagridis, and C. equi. Cryptosporidium parvum was the most prevalent species in our samples. Furthermore, we identified subtypes of C. parvum and C. hominis, which are involved in both human and animal cryptosporidiosis. This is also the first reported occurrence of Cryptosporidium spp. in the Arabian Tahr, to our knowledge. Since the animals examined were all in contact with humans, the possibility of zoonotic spread is possible. Our study correlates with previous reports in the region, building upon the identification of Cryptosporidium sp. However, there is a need to further investigate the endemic populations of Cryptosporidium, including more hosts, sampling asymptomatic animals, and location data.

Cryptosporidium occultus in disguise

As data accumulate in GenBank, the difficulties of delineating species of Cryptosporidium based on nuclear small subunit ribosomal RNA (ssu rRNA) gene information alone becomes increasingly evident. Here, we summarize currently available evidence suggesting that several ssu rDNA sequences primarily referred to as Cryptosporidium suis (some of them from non-suid hosts) should be considered Cryptosporidium occultus.

Molecular characterization of Cryptosporidium spp. in Bactrian camels (Camelus bactrianus) from Yili Kazak Autonomous Prefecture of Xinjiang, China

Introduction

Cryptosporidium spp. is a significant zoonotic parasite. The prevalence and infection characteristics of Cryptosporidium spp. in Bactrian camels in Yili Kazak Autonomous Prefecture have yet to be fully understood. Thus, the molecular epidemiology of cryptosporidiosis in camels was investigated in this region.

Methods

A total of 1,455 fecal samples were collected from 6 counties in three regions (Altay, Tacheng, and Yili) in Yili Prefecture. Nested PCR targeting the small subunit ribosomal RNA (ssu rRNA) gene was used to identify the species or genotypes of Cryptosporidium infection in camels. For C. parvum positive samples, the subtypes were identified using the 60-kDa glycoprotein (gp60) gene.

Results and discussion

The overall infection rate was 8.7% (126/1,455), ranging from 5.6% to 11.7% in different regions, and 4.2% to 15.8% in different counties. A significant difference was observed amongst the counties (p < 0.001). Three species were detected, namely C. andersoni (65.1%, 82/126), C. parvum (34.1%, 43/126), and C. occultus (0.8%, 1/126). Three C. parvum subtypes, If-like-A15G2 (n = 29), IIdA15G1 (n = 4), and IIdA19G1(n = 1) were detected, with If-like-A15G2 being the most prevalent subtype. Camels aged 3-12 months exhibited the highest infection rate (11.4%, 44/387), with no significant difference among age groups (p > 0.05). C. parvum was predominant in camels under 3 months, while C. andersoni prevailed in camels over 3 months. There was an extremely significant difference observed among seasons (p < 0.001), summer had the highest infection rates (16.9%, 61/360). This study collected nearly 1,500 samples and, for the first time, investigated Cryptosporidium spp. infection in camels based on different age groups and seasons. All three Cryptosporidiumspecies identified were zoonotic, posing a potential threat to human health and requiring close attention.

Molecular detection of Cryptosporidium in Alpine musk deer (Moschus chrysogaster) in Gansu Province, Northwest China

Cryptosporidium spp. are protozoa commonly found in domestic and wild animals. Limited information is available on Cryptosporidium in deer worldwide. In this study, 201 fecal samples were collected from Alpine musk deer on three farms in Gansu Province, China. Detection and subtyping of Cryptosporidium were performed by PCR and sequence analysis of the SSU rRNA and gp60 genes. The prevalence of Cryptosporidium infection in Alpine musk deer was 3.9% (8/201), with infection rates of 1.0% (1/100), 2.8% (1/36), and 9.2% (6/65) in three different farms. All positive samples for Cryptosporidium were from adult deer. Two Cryptosporidium species were identified, including C. parvum (n = 2) and C. xiaoi (n = 6). The C. parvum isolates were subtyped as IIdA15G1, while the C. xiaoi isolates were subtyped as XXIIIa (n = 2) and XXIIIg (n = 4). The IIdA15G1 subtype of C. parvum was found for the first time in deer. These results provide important insights into the identity and human infectious potential of Cryptosporidium in farmed Alpine musk deer.

Critters and contamination: Zoonotic protozoans in urban rodents and water quality

Rodents represent the single largest group within mammals and host a diverse array of zoonotic pathogens. Urbanisation impacts wild mammals, including rodents, leading to habitat loss but also providing new resources. Urban-adapted (synanthropic) rodents, such as the brown rat (R. norvegicus), black rat (R. rattus), and house mouse (Mus musculus), have long successfully adapted to living close to humans and are known carriers of zoonotic pathogens. Two important enteric, zoonotic protozoan parasites, carried by rodents, include Cryptosporidium and Giardia. Their environmental stages (oocysts/cysts), released in faeces, can contaminate surface and wastewaters, are resistant to common drinking water disinfectants and can cause water-borne related gastritis outbreaks. At least 48 species of Cryptosporidium have been described, with C. hominis and C. parvum responsible for the majority of human infections, while Giardia duodenalis assemblages A and B are the main human-infectious assemblages. Molecular characterisation is crucial to assess the public health risk linked to rodent-related water contamination due to morphological overlap between species. This review explores the global molecular diversity of these parasites in rodents, with a focus on evaluating the zoonotic risk from contamination of water and wasterwater with Cryptosporidium and Giardia oocysts/cysts from synanthropic rodents. Analysis indicates that while zoonotic Cryptosporidium and Giardia are prevalent in farmed and pet rodents, host-specific Cryptosporidium and Giardia species dominate in urban adapted rodents, and therefore the risks posed by these rodents in the transmission of zoonotic Cryptosporidium and Giardia are relatively low. Many knowledge gaps remain however, and therefore understanding the intricate dynamics of these parasites in rodent populations is essential for managing their impact on human health and water quality. This knowledge can inform strategies to reduce disease transmission and ensure safe drinking water in urban and peri‑urban areas.

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.

Detection and molecular characterization of Cryptosporidium spp. in pet hairless guinea pigs (Cavia Porcellus) from China

Cryptosporidium spp. are common protozoan parasites that can infect humans and animals worldwide. Recently, the hairless guinea pigs (also called Skinny pigs) were introduced into China as pets. However, Cryptosporidium species and their prevalence in these exotic animals were not studied. In this study, fecal samples were collected from a total of 324 hairless guinea pigs from a pet market and four breeding facilities in four provinces of China. The infection rate of Cryptosporidium was 6.8% (22/324). Three Cryptosporidium species were identified, including Cryptosporidium homai (n = 16), Cryptosporidium wrairi (n = 5), and Cryptosporidium hominis plus C. homai (n = 1). Sequence analysis of the small subunit (SSU) rRNA gene showed that the C. hominis isolate was a C. hominis variant, which mostly infects equine animals. However, the identification of C. hominis was not supported by the analysis of other genetic loci. The C. hominis isolate was characterized as C. homai at both 70-kDa heat shock protein (hsp70) and actin genes, indicating a mixed infection. At the 60-kDa glycoprotein (gp60) gene, subtyping of the C. hominis isolate was not successful. Five C. wrairi isolates were identified as subtype VIIaA13T1, which was previously reported in a guinea pig in the USA. The Cryptosporidium spp. identified in this study have no or low zoonotic potential.

Emergence of zoonotic Cryptosporidium parvum in China

Zoonotic cryptosporidiosis is a major public health problem in industrialized nations; in those countries it is caused mainly by Cryptosporidium parvum IIa subtypes that are prevalent in dairy calves. Because of the short history of intensive animal farming in China, strains of C. parvum are found only on some dairy farms in this country and are the IId subtypes. However, the prevalence of C. parvum is increasing rapidly, with IIa subtypes recently detected in a few grazing animals, and both IIa and IId subtypes are emerging in humans. As animal farming intensifies, China may follow in the footsteps of industrialized nations where zoonotic cryptosporidiosis is rampant. One Health and biosecurity measures are urgently needed to slow down the dispersal of autochthonous IId subtypes and imported IIa subtypes.

Molecular identification and biological characterization of Cryptosporidium muris from camels (Camelus bactrianus) in China

BACKGROUND

Cryptosporidium is an opportunistic pathogen that infects a wide variety of vertebrates. The aim of the present study was to characterize Cryptosporidium spp. isolates from Bactrian camels and to foster further understanding of the biological characteristics of the pathogen.

METHODS

Fecal specimens were collected from two 4-year-old Bactrian camels resident at the Kaifeng City Zoo in China and examined for Cryptosporidium. Fecal specimens were screened using the floatation method, and then genomic DNA was extracted from the oocysts and identified by nested-PCR amplification of the small subunit ribosomal RNA (SSU rRNA) gene, the actin gene and the Cryptosporidium oocyst wall-protein (COWP) gene. Subtype analysis was performed based on four minisatellite (MS) loci (MS1, MS2, MS3 and MS16) that were aligned and phylogenetically analyzed to determine the species and subtype of Cryptosporidium. We then established a BALB/c mice infection model and further verified the results through clinical status, pattern of oocyst excretion and histological examination.

RESULTS

Cryptosporidium oocyst isolates from the two Bactrian camels had an average (± standard deviation) size of 7.49 ± 0.13 × 5.70 ± 0.10 μm (n = 50). The sequencing and phylogenetic analysis confirmed the species as C. muris. Multilocus sequence typing analysis indicated that the subtypes were M13, M4, M1 and M5. Following the inoculation of BALB/c mice, we found that the prepatent period and number of oocysts per gram increased with increasing infective dose. Oocysts were first detected in the feces of BALB/c mice at 7-8 days post-infection (dpi), with levels peaking twice thereafter, at 15-16 dpi and 19-20 dpi. Histology and scanning electron microscopy studies showed that the stomach contained gastric pits filled with Cryptosporidium that adhered to the surface of gastric mucosa gland epithelial cells, causing the latter to deform, swell and become disordered.

CONCLUSIONS

The findings of this study indicated that oocysts isolated from Bactrian camels were from C. muris. This is the first report of C. muris isolated from camels in China. More epidemiological data are needed to understand the prevalence and transmission of C. muris in camels in different geographic areas.

Small ruminants and zoonotic cryptosporidiosis

Sheep and goats are commonly infected with three Cryptosporidium species, including Cryptosporidium parvum, Cryptosporidium ubiquitum, and Cryptosporidium xiaoi, which differ from each in prevalence, geographic distribution, and public health importance. While C. parvum appears to be a dominant species in small ruminants in European countries, its occurrence in most African, Asian, and American countries appear to be limited. As a result, zoonotic infections due to contact with lambs and goat kids are common in European countries, leading to frequent reports of outbreaks of cryptosporidiosis on petting farms. In contrast, C. xiaoi is the dominant species elsewhere, and mostly does not infect humans. While C. ubiquitum is another zoonotic species, it occurs in sheep and goats at much lower frequency. Host adaptation appears to be present in both C. parvum and C. ubiquitum, consisting of several subtype families with different host preference. The host-adapted nature of C. parvum and C. ubiquitum has allowed the use of subtyping tools in tracking infection sources. This has led to the identification of geographic differences in the importance of small ruminants in epidemiology of human cryptosporidiosis. These tools have also been used effectively in linking zoonotic transmission of C. parvum between outbreak cases and the suspected animals. Further studies should be directly elucidating the reasons for differences in the distribution and public health importance of major Cryptosporidium species in sheep and goats.