ABSTRACT
Objective To investigate the prevalence of Echinococcus infection in small mammals in Shiqu County, Sichuan Province from 2015 to 2020, so as to provide insights into echinococcosis control in Shiqu County. Methods One setting with frequent activity of small mammals was sampled as the survey site from each of 9 townships where human alveolar echinococcosis was hyperendemic, in Shiqu County, Sichuan Province from 2015 to 2020. Two quadrats measuring 50 m × 50 m were assigned in each survey site during the period between July and August from 2015 to 2020 to capture all small mammals in quadrats, and the species of small mammals were identified by morphological characteristics. All captured small mammals were dissected in the field and Echinococcus infection was identified by visual examinations. The affected organs of Echinococcus-infected small mammals were collected, and Echinococcus infection was detected using PCR assay, with Echinococcus species characterized. The prevalence of Echinococcus infection was calculated in small mammals, and the trends in the prevalence of Echinococcus infection were analyzed during the period from 2015 to 2020. In addition, the prevalence of Echinococcus infection was compared in small mammals using visual examinations and PCR assay. Results A total of 2 692 small mammals were captured in the survey sites of Shiqu County from 2015 to 2020, and morphology characterized 1 360 Microtus fuscus (50.52%) and 1 332 Plateau pika (49.48%). The prevalence rates of Echinococcus infection were 35.63%, 19.16%, 21.41%, 8.40%, 7.68% and 4.44% by visual examinations and 18.96%, 5.36%, 5.61%, 4.58%, 3.30% and 0.37% by PCR assay in small mammals in Shiqu County from 2015 to 2020, both showing a tendency towards a decline year by year (χ2 = 215.024 and 117.045, both P values < 0.001). The prevalence of Echinococcus infection was significantly higher in small mammals by visual examinations than by PCR assay during the period from 2015 to 2020 except in 2018 (χ2= 33.597, 21.815, 51.373, 17.268 and 9.537, all P values < 0.01). PCR assay detected a reduction in the prevalence of E. multilocularis infection from 10.21% to 0.37% and a reduction in the prevalence of E. shiquicus infection from 8.75% to 0 in small mammals in Shiqu County from 2015 to 2020, both appearing a tendency towards a decline year by year (χ2 = 117.045 and 43.436, both P values < 0.001). In addition, the prevalence of E. multilocularis and E. shiquicus infections reduced from 15.19% to 0.45% and from 8.23% to 0 in M. fuscus, and the prevalence of E. multilocularis and E. shiquicus infections reduced from 7.76% to 0 and from 9.01% to 0 in P. pika in Shiqu County from 2015 to 2020. Conclusions M. fuscus and P. pika were dominant species of small mammals in Shiqu County, Sichuan Province from 2015 to 2020, and E. multilocularis infection was mainly found in M. fuscus and E. shiquicus infection mainly found in P. pika. The prevalence of Echinococcus infection appeared a tendency towards a decline in both M. fuscus and P. pika year by year during the period from 2015 to 2020.
ABSTRACT
Objective To analyzed the variant information on the indices regarding fleas from natural foci of Microtus plague in Sichuan epidemic area during 2000 to 2008.Methods Statistical and analytical methods were used on the surveillance data regarding Microtus fuscus plague.Results There were 19 flea species identified and the share of Callopsylla sparsilis was 62.79 percent while the share of Amphipsylla tuta tuta was 30.90 percent on Microtus fuscus plague.The infection rate of fleas and the flea index were the highest in October and the lowest in December and March.Species as Callopsylla sparsilis,Amphipsylla tuta tuta and Rhadinopsylla dahurica vicina could naturally infect the Yersinia pestis.Conclusion Microtus fuscus plague could become epidemic when animals and flea species were infected.We should emphasis on plague monitoring program so as to prevent the occurrence of the disease.
ABSTRACT
Objective To analyze the epidemic tendency of Microtus fascus plague during 2000-2008 in Sichuan province. Methods To investigate the plague each year according to "overall Plan of the Plague in the Whole Nation" and "Surveillance Program of Sichuan Province Plague". Results There were plague epidemic from 2000 to 2008, with the average density as 312.41/ha. 42.57% of the Microtus fuscus were infected by body Fleas. The Fleas Index was 0.88 and the Index for nest Fleas of Microtas fuscus was 55.89. Six kinds of animals were infected by not only the Microtus fuscus but also herd-dog, sand fox, Tibetan sheep, domestic cats and Cricetulus longicaulatus as well. The positive rate of live Microtus fuscus was 0.32% but 22.99% in the dead Microtus fuscus. The overall positive rate on serological test was 6.70%. There were 4 Sections, 11 species and 19 kinds Fleas identified and carrying 3 kinds of fleas, Callopsylla sparsilis, Amphipsylla tntua tutua and Rhadinopsylla dahurica vicina, with the overall infection rate as 0.054%. Conclusion Plague among Microtus fuscus showed a continuous epidemic in Sichuan province during 2000-2008.