Seasonal variation of ticks in Yantai,Shandong Province,China:A study based on the circular distribution method
Objective To investigate the seasonal variation of on-host and questing ticks in Yantai,Shandong Province,China,so as to provide a scientific basis for the control planning development and the control and prevention of ticks and tick-borne diseases.Methods From March to October in 2021-2023,questing ticks were collected in the wild by the tick drag-flag method in nine districts (cities) of Yantai,and on-host ticks on the body surface of domesticated animals (cattle,sheep,and dog) were collected by tick detection method.The monthly distribution data of ticks in 2021-2023 were obtained and analyzed with the circular distribution method for the peak days and peak periods of questing ticks in different habitats and on-host ticks in different host animals.Results The γ values of questing ticks in various habitats and on-host ticks in various hosts in Yantai ranged from 0.594 to 0.908 (P<0.05),showing obvious seasonality.The peak period of seasonal variation in questing ticks appeared from May 18 to September 13,with the peak day on July 16,and that in on-host ticks appeared from May 14 to August 28,with the peak day on July 6.The peak periods of seasonal variation in questing ticks from rural external environment rural areas and scenic areas appeared from May 19 to September 15 and May 17 to July 21,with the peak days on July 17 and June 18,respectively,and those in on-host ticks on the body surface of cattle,sheep,dogs (rural areas),and dogs (urban areas) appeared from August 24 to October 14,May 13 to August 26,May 18 to September 8,and June 1 to July 31,with the peak days on September 19,July 5,July 14,and July 1,respectively.Conclusions Questing and on-host ticks in Yantai show a seasonal distribution.The seasonal characteristics of questing and on-host ticks should be fully considered in the control of ticks,with targeted control measures being taken.According to the changes in tick density,personal protection should be done to minimize exposure,and scientific tick extermination should be carried out to reduce the incidence of tick-borne diseases.
Circular distribution methodSeasonalityTickQuesting tickOn-host ticks