Occurrence and genetic characterization of Enterocytozoon bieneusi in pet dogs in Yunnan Province, China.

Enterocytozoon bieneusi is the most common microsporidian species in humans and can affect over 200 animal species. Considering possible increasing risk of human E. bieneusi infection due to close contact with pet dogs and identification of zoonotic E. bieneusi genotypes, 589 fresh fecal specimens of pet dogs were collected from Yunnan Province, China to determine the occurrence of E. bieneusi, characterize dog-derived E. bieneusi isolates, and assess their zoonotic potential at the genotype level. Enterocytozoon bieneusi was identified and genotyped by PCR and sequencing of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene. Twenty-nine specimens (4.9%) were positive. A statistical difference was observed in occurrence rates of E. bieneusi in pet dogs among 11 sampling sites by Fisher's exact test. Fifteen genotypes were identified and all of them phylogenetically belonged to zoonotic group 1, including four known genotypes (EbpC, D, Peru 8, and Henan-III) and 11 novel genotypes. Genotype Henan-III was reported in dogs for the first time. The finding of known genotypes found previously in humans and novel genotypes falling into zoonotic group 1 indicates that dogs may play a role in the transmission of E. bieneusi to humans in the investigated areas.

Title: Occurrence et caractérisation génétique d'Enterocytozoon bieneusi chez les chiens de compagnie dans la province du Yunnan, Chine. Abstract: Enterocytozoon bieneusi est l'espèce de microsporidies la plus répandue chez l'homme et peut affecter plus de 200 espèces animales. Compte tenu du risque accru possible d'infection humaine à E. bieneusi en raison d'un contact étroit avec des chiens de compagnie et de l'identification de génotypes zoonotiques d'E. bieneusi, 589 échantillons fécaux frais de chiens de compagnie ont été collectés dans la province du Yunnan, en Chine, pour déterminer la présence d'E. bieneusi, caractériser les isolats obtenus de chiens, et évaluer leur potentiel zoonotique au niveau du génotype. Enterocytozoon bieneusi a été identifié et génotypé par PCR et séquençage de la région d'espacement transcrit interne (ITS) du gène de l'ARN ribosomal (ARNr). Vingt-neuf échantillons (4,9%) étaient positifs. Une différence statistique a été observée dans les taux de présence d'E. bieneusi chez les chiens de compagnie parmi 11 sites d'échantillonnage par le test exact de Fisher. Quinze génotypes ont été identifiés et tous appartenaient phylogénétiquement au groupe zoonotique 1, dont quatre génotypes connus (EbpC, D, Peru 8 et Henan-III) et 11 nouveaux génotypes. Le génotype Henan-III est signalé pour la première fois chez le chien. La découverte de génotypes connus précédemment trouvés chez l'homme et de nouveaux génotypes appartenant au groupe zoonotique 1 indique que les chiens peuvent jouer un rôle dans la transmission d'E. bieneusi aux humains dans les zones étudiées.

Epidemiological survey of cystic echinococcosis in southwest China: From the Qinghai-Tibet plateau to the area of Yunnan.

BACKGROUND: Echinococcosis is prevalent in 9 provinces in Western and Northern China. An epidemiological survey of echinococcosis in 2012 and 2016 showed cases of echinococcosis in Yunnan Province. AIM: To understand the spatial distribution and epidemiological characteristics of echinococcosis in Yunnan for the prevention and control of echinococcosis and to reduce the risk of infection in Yunnan Province. METHODS: Based on the China Information System for Disease Control and Prevention (CISDCP), echinococcosis cases reported from 36 hospitals and 34 Centers for Disease Control were investigated and epidemiologically analyzed from 2021 to 2022. The exclusion criteria included suspected cases, same case only counted once and cases not from Yunnan. A total of 705 cases were investigated, of which 397 cases were suitable for statistical analysis. In these 397 cases, epidemiological investigation was tracked in 187 cases. All data were inputted using double entry in the Excel database, with error correction by double-entry comparison. The data on echinococcosis cases in Yunnan Province were analyzed by ArcGIS 10.1 software to generate a density map of echinococcosis distribution. All statistical analyses were conducted using SPSS 17.0, including the chi-square test, linear regression test and logistic univariate and multivariate regression analyses. RESULTS: A total of 397 cases were found in 89 counties in Yunnan Province. The number of cases in the top three prefectures were Dali (38.1%), Diqing (10.1%), and Kunming (8.3%), and the top five counties were Jianchuan (9.1%), Shangri La (8.3%), Eryuan (7. 6%), Heqing (6.9%), and Dali Districts (5.0%). There were significant differences between the different areas. The case reporting rate by CISDCP (33.8%) was low; the first case was reported by CISDCP in 2002, and the highest number of cases was 50 (2017). Confirmed and clinical cases accounted for 62.5% and 37.5%, respectively. However, 90.9% of the cases of hydatid disease were reported by the hospital system, and only 9.1% of the cases of hydatid disease were found in the community through active screening. The difference between the two methods of case detection was statistically significant. Most of the cases of echinococcosis were found in farmers/herdsmen (75.1%) and students (9.1%). In addition, Han (43.6%) and Bai (26.2%) had a higher incidence of infection than other nationalities, and the liver (87.7%) and lung (6.8%) were the most common sites of cyst formation. Among the analyzed cases, 187 were epidemiologically analyzed and the clinical symptoms were not obvious in the early stage in 47.1% of cases. The results of logistic regression analysis showed that the age group, education level, presence of dogs in the family (either previously or currently), and handwashing (occasionally or not) were factors related to echinococcosis infection. 55.6% of cases were in endemic areas, and 44.4% of cases were in non-endemic areas. Among 83 cases in non-endemic areas, only 4 cases had been to endemic areas and had a history of living, working, travelling, or hunting in echinococcosis epidemic areas. CONCLUSION: Cases of echinococcosis were reported throughout the entire Yunnan province, with the majority distributed in Western Yunnan, suggesting that echinococcosis control should be strengthened in this area. We suggest that an epidemiological investigation should be carried out in the future, based on the clues from newly discovered cases in hospitals or from the CISDCP. The newly discovered cases in the hospital provided clues to comprehensively determine the location of cases and where epidemic spot investigation should be conducted.