Objective:To study echinococcosis in the population and canine Echinococcus infection in Yushu City, Qinghai Province, and to explore the current epidemic situation and main transmission species of Echinococcus. Methods:In June 2023, a multi-stage sampling method was used to select 2 villages each in Shanglaxiu Township and Longbao Town, Yushu City, Qinghai Province. Each village included at least 100 permanent residents who had lived locally for at least 1 year and were 2 years old or older as the survey subjects. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum antibodies against Echinococcus larvae in the population, and B-mode ultrasound was used for abdominal organ scanning. Meanwhile, on the main roads of Shanglaxiu Township and Longbao Town, canine feces were collected in designated areas at intervals. ELISA was used to detect the antigen of canine fecal Echinococcus, and PCR was used to detect the types of parasites ( Echinococcus multilocularis, Echinococcus granulosus and Echinococcus shiquicus). Results:A total of 511 residents were investigated in Yushu City, and the positive rate of serum Echinococcus larvae antibodies in the population was 26.22% (134/511), and the detection rate of echinococcosis B-mode ultrasound was 1.37% (7/511). Among them, the detection rates of B-mode ultrasound for cystic echinococcosis (CE) and alveolar echinococcosis (AE) were 1.17% (6/511) and 0.20% (1/511), respectively. The positive rate of Echinococcus antigen in 543 canine feces detected by ELISA was 12.89% (70/543). PCR was used to test 497 canine feces, and the detection rate of Echinococcus was 3.02% (15/497). Among them, the detection rate of Echinococcus multilocularis was higher than that of Echinococcus granulosus [2.82% (14/497) vs 0.20% (1/497)], and the difference was statistically significant (χ 2 = 11.44, P < 0.001). No Echinococcus shiquicus was detected. Conclusions:The positive rates of Echinococcus larvae antibodies in the population and canine Echinococcus antigen in Yushu City, Qinghai Province are both relatively high. There is a mixed epidemic of CE and AE, with Echinococcus multilocularis being the main species.

Objective:To study echinococcosis in the population and canine Echinococcus infection in Yushu City, Qinghai Province, and to explore the current epidemic situation and main transmission species of Echinococcus. Methods:In June 2023, a multi-stage sampling method was used to select 2 villages each in Shanglaxiu Township and Longbao Town, Yushu City, Qinghai Province. Each village included at least 100 permanent residents who had lived locally for at least 1 year and were 2 years old or older as the survey subjects. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum antibodies against Echinococcus larvae in the population, and B-mode ultrasound was used for abdominal organ scanning. Meanwhile, on the main roads of Shanglaxiu Township and Longbao Town, canine feces were collected in designated areas at intervals. ELISA was used to detect the antigen of canine fecal Echinococcus, and PCR was used to detect the types of parasites ( Echinococcus multilocularis, Echinococcus granulosus and Echinococcus shiquicus). Results:A total of 511 residents were investigated in Yushu City, and the positive rate of serum Echinococcus larvae antibodies in the population was 26.22% (134/511), and the detection rate of echinococcosis B-mode ultrasound was 1.37% (7/511). Among them, the detection rates of B-mode ultrasound for cystic echinococcosis (CE) and alveolar echinococcosis (AE) were 1.17% (6/511) and 0.20% (1/511), respectively. The positive rate of Echinococcus antigen in 543 canine feces detected by ELISA was 12.89% (70/543). PCR was used to test 497 canine feces, and the detection rate of Echinococcus was 3.02% (15/497). Among them, the detection rate of Echinococcus multilocularis was higher than that of Echinococcus granulosus [2.82% (14/497) vs 0.20% (1/497)], and the difference was statistically significant (χ 2 = 11.44, P < 0.001). No Echinococcus shiquicus was detected. Conclusions:The positive rates of Echinococcus larvae antibodies in the population and canine Echinococcus antigen in Yushu City, Qinghai Province are both relatively high. There is a mixed epidemic of CE and AE, with Echinococcus multilocularis being the main species.

Objective To investigate the prevalence of Echinococcus infections in small rodents around human residential areas in Yushu City, Qinghai Province in 2023, so as to provide insights into precision echinococcosis control. Methods One or two quadrats, each measuring 50 m × 50 m, were randomly assigned in Shanglaxiu Township and Longbao Township, Yushu City, Qinghai Province on June 2023, respectively, and 300 plate-type mouse traps, each measuring 12.0 cm × 6.5 cm, were assigned in each quadrat. Small rodents were captured during the period between 10 : 00 and 18 : 00 each day for 4 days. Then, all captured small rodents were identified and dissected, and liver specimens with suspected Echinococcus infections were subjected to pathological examinations. The Echinococcus cytochrome c oxidase 1 (cox1) gene was amplified using PCR assay, and the sequence of the amplified product was aligned to that was recorded in the GenBank to characterize the parasite species. In addition, a phylogenetic tree of Echinococcus was generated based on the cox1 gene sequence using the neighbor-joining method. Results A total of 236 small rodents were captured in Shanglaxiu and Longbao townships, Yushu City, including 65 Qinghai voles and 51 plateau pikas in Shanglaxiu Township, and 62 Qinghai voles and 58 plateau pikas in Longbao Township, and there was no significant difference in the constituent ratio of small rodents between the two townships (χ² = 0.294, P > 0.05). Seven plateau pikas and 12 Qinghai voles were suspected to be infected with Echinococcus by dissection, and pathological examinations showed unclear structure of hepatic lobules and disordered hepatocyte arrangement in livers of small rodents suspected of Echinococcus infections. PCR assay identified E. shiquicus DNA in 7 Qinghai voles, which were all captured from Shanglaxiu Township. Phylogenetic analysis showed that the cox1 gene sequence of Echinococcus in small rodents was highly homologous to the E. shiquicus cox1 gene sequence reported previously. Conclusion Plateau pika and Qinghai vole were predominant small rodents around human residential areas in Yushu City, Qinghai Province in 2023, and E. shiquicus infection was detected in Qinghai voles.