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

Investigation of Cryptosporidium spp. and Enterocytozoon bieneusi in free-ranged livestock on the southeastern Qinghai-Xizang Plateau, China

BACKGROUND

Cryptosporidium spp. and Enterocytozoon bieneusi are zoonotic pathogens with global distribution, infecting humans and various livestock. For yaks, Tibetan sheep and horses, the traditional grazing models still hold a main position. After these animals become infected, it not only hinders the development of animal husbandry but also increases the risk of Cryptosporidium spp. and E. bieneusi transmission between livestock and herdsmen.

METHODS

In the present study, a total of 750 fecal samples were collected from yaks, Tibetan sheep and horses in Shiqu County, Sichuan Province, from July to August 2023, and were analyzed by nested Polymerase chain reaction (PCR) amplification of the small subunit ribosomal RNA (SSU rRNA) gene of Cryptosporidium spp. and internal transcribed spacer (ITS) gene of E. bieneusi.

RESULTS

The prevalence of Cryptosporidium spp., and E. bieneusi were 2.1% (16/750) and 1.5% (11/750), respectively. Mixed infections of Cryptosporidium spp. and E. bieneusi were detected in two samples. Among these positive fecal samples, one Cryptosporidium species (Cryptosporidium suis) was identified in the yaks (n = 11), Tibetan sheep (n = 1), and horses (n = 4). Three E. bieneusi genotypes, including a known genotype BEB4 and two novel ones SQY1 and SQY2, were identified in the yaks (n = 7), while in Tibetan sheep (n = 4) only the known genotype BEB4 was detected. The novel genotype SQY1 was grouped into the human-pathogenic Group 1, and the known genotype BEB4 and the novel genotype SQY2 were grouped into Group 2. Enterocytozoon bieneusi was not detected in horses.

CONCLUSIONS

Cryptosporidium suis was identified in yaks and horses while zoonotic E. bieneusi genotype BEB4 in Tibetan sheep for the first time, expanding their host ranges. These findings suggested that yaks, Tibetan sheep and horses could act as potential sources of human Cryptosporidium spp. and E. bieneusi infections, implying that the presence of zoonotic species/genotypes could pose a threat to public health.

Cross-species transmission of Cryptosporidium in wild rodents from the southern region of Zhejiang Province of China and its possible impact on public health

Wild rodents serve as reservoirs for Cryptosporidium and are overpopulated globally. However, genetic data regarding Cryptosporidium in these animals from China are limited. Here, we have determined the prevalence and genetic characteristics of Cryptosporidium among 370 wild rodents captured from three distinct locations in the southern region of Zhejiang Province, China. Fresh feces were collected from the rectum of each rodent, and DNA was extracted from them. The rodent species was identified by PCR amplifying the vertebrate cytochrome b gene. Cryptosporidium was detected by PCR amplification and amplicon sequencing the small subunit of ribosomal RNA gene. Positive samples of C. viatorum and C. parvum were further subtyped by analyzing the 60-kDa glycoprotein gene. A positive Cryptosporidium result was found in 7% (26/370) of samples, involving five rodent species: Apodemus agrarius (36), Niviventer niviventer (75), Rattus losea (18), R. norvegicus (155), and R. tanezumi (86). Their respective Cryptosporidium positive rates were 8.3%, 5.3%, 11.1%, 7.1%, and 7.0%. Sequence analysis confirmed the presence of three Cryptosporidium species: C. parvum (4), C. viatorum (1), and C. muris (1), and two genotypes: Cryptosporidium rat genotype IV (16) and C. mortiferum-like (4). Additionally, two subtypes of C. parvum (IIdA15G1 and IIpA19) and one subtype of C. viatorum (XVdA3) were detected. These results demonstrate that various wild rodent species in Zhejiang were concurrently infected with rodent-adapted and zoonotic species/genotypes of Cryptosporidium, indicating that these rodents can play a role in maintaining and dispersing this parasite into the environment and other hosts, including humans.

Molecular detection and genetic variability of Cryptosporidium spp. in wild Asian house shrews (Suncus murinus) from southern Zhejiang province, China

Shrews play a crucial role as repositories for diverse pathogens linked to zoonotic infectious diseases. However, the genetic information regarding Cryptosporidium in Chinese shrews remains unexplored. The objectives of this study were twofold: to determine the occurrence rate of Cryptosporidium spp. in wild shrews residing in the southern part of Zhejiang Province, China, and to investigate their genetic characteristics. A total of 282 wild shrews were captured between April and October of 2023. The detection of Cryptosporidium in fecal samples, collected from each animal's rectum, was performed using PCR and sequencing of the partial small subunit of ribosomal RNA (SSU rRNA) gene. The 60-kDa glycoprotein (gp60) gene was utilized to further subtype the positive samples of C. viatorum and C. parvum. All animals were identified as Suncus murinus, and a positive result for Cryptosporidium was obtained in 14.2 % (40/282) of the samples. The following species and genotypes were identified: C. ratti (n = 19), C. parvum (n = 2), C. viatorum (n = 1), Cryptosporidium rat genotype IV (n = 13), and Cryptosporidium skunk genotype (n = 5). Furthermore, the subtypes IIdA15G1 and XVdA3 were detected within C. parvum and C. viatorum, respectively. Molecular evidence indicates that S. murinus is concurrently infected with rodent-adapted and zoonotic species/genotypes, actively contributing to the dissemination of cryptosporidiosis.

Prevalence and potential risk factors for Cryptosporidium spp. infection in horses from Egypt

Cryptosporidium is an intestinal protozoan that cause diarrhea in livestock all over the world and have zoonotic importance. The present study aimed to determine the prevalence of Cryptosporidium spp. in horses in Egypt and evaluate the associated risk factors. A total of 420 fecal samples were collected from three governorates (Giza, Kafr ElSheikh and Qalyubia) and examined microscopically using Ziehl-Neelsen staining method. The overall prevalence of Cryptosporidium spp. was 29% and Kafr ElSheikh governorate had the highest rate in comparison to other areas. The prevalence of Cryptosporidium spp. in examined horses had significant association with sex, age, type of management, absence of bedding and presence of dogs. The higher prevalence rate was observed in females (32.2%), age group less than two years (43.2%), mixed (grazing and stable) horses (36.1%), animals had history of diarrhea (33%), absence of bedding (35.1%) and contact with dogs (35.7%). These findings give baseline data for further research. It is necessary to establish control strategy for Cryptosporidium spp. infection in order to lower the risk of infection in animals and human.

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

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

Cryptosporidium equi n. sp. (Apicomplexa: Cryptosporidiidae): biological and genetic characterisations

The horse genotype is one of three common Cryptosporidium spp. in equine animals and has been identified in some human cases. The species status of Cryptosporidium horse genotype remains unclear due to the lack of extensive morphological, biological, and genetic data. In the present study, we have conducted biological and whole genome sequence analyses of an isolate of the genotype from hedgehogs and proposed to name it Cryptosporidium equi n. sp. to reflect its common occurrence in equine animals. Oocysts of C. equi measured 5.12 ± 0.36 μm × 4.46 ± 0.21 μm with a shape index of 1.15 ± 0.08 (n = 50). Cryptosporidium equi was infectious to 3-week-old four-toed hedgehogs (Atelerix albiventris) and mice, with a prepatent period of 2-9 days and a patent period of 30-40 days in hedgehogs. It was not infectious to rats and rabbits. Phylogenetic analyses of small subunit rRNA, 70 kDa heat shock protein, actin, 60 kDa glycoprotein and 100 other orthologous genes revealed that C. equi is genetically distinct from other known Cryptosporidium species and genotypes. The sequence identity between C. equi and Cryptosporidium parvum genomes is 97.9%. Compared with C. parvum, C. equi has lost two MEDLE genes and one insulinase-like protease gene and gained one SKSR gene. In addition, 60 genes have highly divergent sequences (sequence differences ≥ 5.0%), including those encoding mucin-like glycoproteins, insulinase-like peptidases, and MEDLE and SKSR proteins. The genetic uniqueness of C. equi supports its increasing host range and the naming of it as a valid Cryptosporidium species. This is the first known use of whole genome sequence data in delineating new Cryptosporidium species.