Abstract:

Objective To understand the behavioral activities of the different wild animals as intermediate hosts for Echinococcus spp. in Shiqu County, and to explore their exposure risk in the transmission of Echinococcus spp., in order to provide scientific basis for prevention and control. Methods During 2018—2020, 12 observation sites were set up within a radius of 1 km from the settlements of Niga Town and Odoma Township in Shiqu County, at varied months, and in each observation site infrared-triggered cameras were used to record the ground activity of the intermediate host animals of Echinococcus spp. within the range of 6 m. The infrared cameras were installed on a telephone pole or fence at about 100 cm high for over 3 days to record a 10-s or 25-s video after each triggering. Animal samples were captured within the range of camera-recorded, identified for species, and underwent PCR amplification of cytochrome b gene (Cyt b) followed by double-stranded DNA sequencing. The sequences were compared by BLASTN in GenBank to identify the species. Results Video records were obtained from all 12 observation sites, with a total length of 743 minutes, and 59 small mammals were captured, of which those from 6 observation sites were identified to be Ochotona curzoniae of the order Lagomorpha, with sequence homology of > 99% to the Cyt b gene of O. curzoniae in the GenBank database (Accession No. FJ227464); animals from the other 6 observation sites were identified to be Neodon fuscus, with sequence homology of > 99% to the Cyt b gene of N. fuscus in the GenBank database (Accession No. KU214680, KU214681). At the 6 observation sites of O. curzoniae, the daytime ground activity started at 6 ∶ 46 and ended at 20 ∶ 41 with an activity peak at 9 ∶ 00, 12 ∶ 00, and 17 ∶ 00, the highest at 17 ∶ 00; the activities on the ground included grazing, running, watching, and burrowing, accounting for 45.8% (546/1 192), 33.6% (400/1 192), 16.9% (201/1 192), 2.9% (34/1 192), and 0.9% (11/1 192), respectively. At the 6 observation sites for N. fuscus, the ground activity started at 7 ∶ 18 and ended at 20 ∶ 14 with an activity peak at 9 ∶ 00, 12 ∶ 00, 14 ∶ 00 and 17 ∶ 00, the highest at 9 ∶ 00; the activities on the ground included running, grazing, watching, burrowing, playing, cleaning body, and collecting hay, accounting for 34.2% (131/383), 32.9% (126/383), 19.6% (75/383), 6.3% (24/383), 4.2% (16/383), 1.6% (6/383), and 1.3% (5/383), respectively. Conclusion There are certain differences in the daytime activity of different intermediate host animals of Echinococcus spp. The activity start time, ending time, activity frequency and activity status are different between O. curzoniae and N. fuscus. The O. curzoniae activity started earlier and ended later than N. fuscus. The O. curzoniae animals are more active throughout the day. The N. fuscus animals are more active in the morning than in the afternoon, while the O. curzoniae animals are more active in the afternoon. The N. fuscus animals are more vigilant toward outside than the O. curzoniae animals, which indicated that the O. curzoniae showed higher risk to expose into the predation range of the definitive hosts.

Key words: Shiqu County, Echinococcus spp., Echinococcosis, Infrared-triggered camera, Ochotona curzoniae, Neodon fuscus, Ground activity