Rongsheng Mi

Background: Cystic echinococcosis (CE) remains a significant zoonotic burden in the pastoral regions of China. Yili Prefecture in Xinjiang is a high-risk area, yet comprehensive data are lacking on the prevalence and molecular characteristics of Echinococcus granulosus in its primary intermediate host, sheep. Methods: From 2020 to 2024, a total of 2700 sheep livers were visually inspected for hydatid cysts infection at one randomly selected slaughterhouse in each of the nine counties of Yili Prefecture. Ninety cyst-positive samples were subjected to morphological examination and molecular genotyping by amplifying and sequencing the nad2 gene. Results: The overall prevalence of E. granulosus was 22.0% (594/2700). County-level prevalence ranged from 18.3% (Zhaosu County) to 25.7% (Huocheng County), with no significant differences observed among the counties (p > 0.05) except between Huocheng and Zhaosu. Temporally, the annual prevalence fluctuated between 20.2% and 24.2% without a consistent downward trend. Genotyping revealed that the G1 genotype was overwhelmingly dominant (95.2%, 79/83), with a minor circulation of the G3 genotype (4.8%, 4/83). Fourteen haplotypes were identified; Hap1 was the central and predominant haplotype (47.0%, 39/83), found in all counties. Network analysis suggested a recent population expansion of the parasite. Conclusion: This five-year surveillance study reveals a persistently high prevalence and complex genetic diversity of E. granulosus in sheep in Yili Prefecture. The dominance of the zoonotic G1 genotype indicates a substantial public health threat. Our findings provide crucial data for contributing to the development of local control strategies. However, the specific reasons for the high infection rate in sheep remain unclear, as this study did not include examinations of definitive hosts or environmental samples; this gap should be addressed in future research.

Toxoplasma gondii is an obligate intracellular opportunistic protozoan parasite. T. gondii invasion disturbs the balance between reactive oxygen species (ROS) production and antioxidant capacity in the host, triggering the oxidative stress response. Thioredoxin reductase (TR) of T. gondii helps to escape ROS-induced damage in the host, whereas T. gondii rhoptry protein 16 (ROP16) downregulates host innate immunity to suppress excessive inflammation and inhibit ROS production. However, whether TR and ROP16 synergistically promote resistance to ROS-induced damage remains unclear. Here, we used the CRISPR/Cas9 technology to successfully obtain a double TR and ROP16 gene knockout T. gondii strain. The double deletion of TR and ROP16 in T. gondii weakened its growth ability in vitro and decreased its virulence in vivo. Moreover, the double deletion of TR and ROP16 resulted in a lower antioxidant capacity, higher degree of lipid oxidation, and elevated ROS levels in the parasite and host cells. Interestingly, the deletion of the TR and ROP16 genes in T. gondii synergistically increased IL-12 levels, which triggered host cells to produce more ROS to resist T. gondii infection. These results show that TR and ROP16 in T. gondii play a synergistic role, facilitating resistance to ROS damage incurred by host immune cells through different pathways.

Echinococcosis is a worldwide disease endemic to the western region of China. In 2023, echinococcosis was detected in one of 27 wild boars (Sus scrofa) in Yili Prefecture, Xinjiang, northwestern China. Histopathological staining and full sequence mitochondrial (mt) analysis were used to determine the infection genotype. Echinococcus granulosus was detected in the wild boar liver, and the cystic lesion characteristics indicated the E. granulosus genotype (G1). This case is the first confirmation of wild boar serving as a transmitter for the G1 genotype of E. granulosus within China. These findings suggest that surveillance is needed to assess the risk of E. granulosus sensu lato transmission to humans and wild animals.

Hen eggs are one of the most popular foods worldwide, and their safety is critical. Employing 16S rRNA full-length sequencing is an effective way to identify microorganisms on or in eggs. Here, hen eggs collected from poultry farms over four seasons, as well as from markets in Shanghai, were analyzed with third-generation sequencing. Firmicutes (44.46%) and Proteobacteria (35.78%) were the two dominant phyla, and Staphylococcus, Acinetobacter, Aerococcus, Psychrobacter, and Lactobacillus were the dominant genera. The dominant genera on the eggshell surfaces from the farms varied with the seasons, and the highest contamination of Staphylococcus (32.93%) was seen in the eggs collected during the summer. For the market samples, Pseudomonas was the most abundant in content, with Staphylococcus being the most-often genera found on the eggshell surfaces. Moreover, several potential pathogenic bacteria including Riemerella anatipestifer (species), Klebsiella (genus), and Escherichia/shigella (genus) were detected in the samples. The results revealed the impacts of weather on the microbiota deposited on an eggshell’s surface, as well as the impacts due to the differences between the contents and the surface. The results can help disinfect eggs and guide antibiotic selection.

Enterocytozoon bieneusi is reported to be a common microsporidian of humans and animals in various countries. However, scarce information on E. bieneusi has been recorded in cats ( Felis catus ) and dogs ( Canis familiaris ) in China. As such, we undertook molecular epidemiological investigation of E. bieneusi in cats and dogs in Shanghai, China. A total of 359 genomic DNAs were extracted from individual faecal samples from cats ( n = 59) and dogs ( n = 300), and then tested using a nested PCR-based sequencing approach employing internal transcribed spacer (ITS) of nuclear ribosomal DNA as the genetic marker. Enterocytozoon bieneusi was detected in 34 of all 359 (9.5%) faecal samples from cats (32.2%; 19/59) and dogs (5.0%; 15/300), including 24 stray cats and dogs (22.6%; 24/106), as well as ten household/raised cats and dogs (4.0%; 10/253). Correlation analyses revealed that E. bieneusi positive rates were significantly associated with stray cats and dogs ( P < 0.05). The analysis of ITS sequence data revealed the presentation of five known genotypes CD7, CHN-HD2, D, PtEb IX and Type IV and two novel genotypes D-like1 and PtEb IX-like1. Zoonotic genotype D was the predominant type with percentage of 61.8 (21/34). Phylogenetic analysis of ITS sequence data sets showed that genotypes D, D-like1 and Type IV clustered within Group 1, showing zoonotic potential. The others were assigned into Group 10 with host specificity. These findings suggested that cats and dogs in Shanghai harbor zoonotic genotype D of E. bieneusi and may have a significant risk for zoonotic transmission. Further insight into the epidemiology of E. bieneusi in animals, water and the environment from other areas in China will be important to have an informed position on the public health significance of microsporidiosis caused by this microbe.

Cystic echinococcosis (CE), caused by the metacestode Echinococcus granulosus sensu stricto (s.s.), is an important zoonotic parasite, endemic in the Altai region of China. It is a serious human health risk and causes livestock losses. To evaluate the prevalence, genetic variation, and population structure of CE, 2898 sheep and 703 cattle were examined from October 2019 to mid-February 2020 in the Altai region (Altai, Habahe, Fuhai, and Buerjin). Sheep had an infection rate of 4.52% (131/2898) and cattle had an infection rate of 4.84% (34/703). In total, 180 cyst isolates were obtained, including 131 sheep, 34 cattle, and 15 from CE human patients. The cysts were investigated using mitochondrial cytochrome C oxidase subunit 1 (cox1). Polymerase Chain Reaction (PCR) results showed that, among the two genotypes of E. granulosus s.s., there were 22 different haplotypes (Haps). Phylogenetic analysis and parsimony network indicated that seventeen (77.27%) Haps belonged to the sheep strain (G1 genotype) and five Haps (22.73%) belonged to the buffalo strain (G3 genotype). Hap3 was the most common haplotype (65.00%, 112/180), which belongs to the G1 genotype. Hap18–Hap22 were found in human samples, indicating that sheep and cattle reservoirs of human CE. Molecular diversity indices revealed the high levels of haplotype diversity and relatively low levels of nucleotide diversity. Tajima’s D and Fu’s Fs tests displayed that the Altai population had a significant deviation from neutrality. Based on pairwise fixation index (Fst) values, a low level of genetic differentiation was found between the populations of E. granulosus s.s. isolated from different regions. The present survey findings represent an epidemiological survey of CE in the Altai region where there were two genotypes simultaneously and will provide more information on the genetic structure of E. granulosus s.s. within this region.

Toxoplasma gondii can infect all mammals, including humans, and can cause serious public health problems and economic losses. Pork is considered an important source of infection for humans, and seroepidemiological surveys are used to assess the level of infection in pig herds. To understand the current seroprevalence and potential risk factors of T. gondii in pigs in Chongqing, a total of 1221 serum samples collected from seven slaughterhouses in five districts from 2015 to 2019 were analyzed for antibodies against the protozoan by enzyme-linked immunosorbent assay. The overall seropositive rate for T. gondii antibodies in Chongqing was 11.1%. The rate varied among the different districts (9.8–15.2%), slaughterhouses (8.0–18.4%), seasons (8.1–14.6%), and years (6.3–14.7%). These results suggest that the season and year were potential risk factors for T. gondii infection in pigs of Chongqing. The study provides prevalence and risk factor data that may help manage livestock and human infections in downstream areas. The Clinical Trial Registration number was SV-20150605-01.