Investigation Of Sheep Infected With Ticks In Shanshan County And Analysis Of Anti Tick Effect Of Recombinant Cathepsin L Immunization

Ixodes are ectoparasite that transmits various diseases after biting humans and livestock.Hosts bitten by infected ticks can develop symptoms such as wound infection,dermatitis,and abscesses.Ticks transmit pathogens that impact both human and animal health that lead to huge economic losses.Although the application of chemical drugs to control ticks has many shortcomings.However,it is still the main means of the prevention and control of ticks.Therefore,anti-tick vaccines seems to be the most effective environmentally approach to controlling ticks.In this study,we selected five villages from Shanshan County,in Xinjiang as study sites.andcollect ticks from sheep surface and natural environment in this area,then carried outthe morphological identification of ticks followed bystatistical analysis according to the sampling location.Next,sheep were immunized with(r Has CPL)to detect the antibody titer,in the same time,the anti-Hyalomma asiaticum protection test was carried out.Our study lays the foundation for the prevention and control of ticks in spring in Shanshan County and the application of Has CPL.(1)To understand the genera and distribution of ticks in Shanshan County in spring,From March to May in 2021,30 sheep were randomly selected from each village,150 in total.Collection of tick samples,1392 and 1007 ticks collected from the body surface of 150 sheep and the natural environment,respectively.A stereo microscope was used to morphologically identified tick species,count the status,and categorize infested rates of ticks on sheep.Our results showed that there are 5 species of ticks were found,which belong to the 3 genera from Ixodida and Argasidae.They were Hyalomma asiaticum,Hyalomma anatolicum,Rhipicephalus sanguineous,Rhipicephalus turanicus of the Ixodida,and Ornithodoros lahorensis of the Argasidae.Among them,the tick infection rate and tick index of sheep were the highest in May,were 68.66% and843,respectively,It is suggested that the peak of the spring tick epidemic in Shanshan County is in May.There are also differences between villages,among them,the epidemic in Village Kagetuoer is more serious.a total of 1 326 animals were collected,accounting for 55.27%.A total of 1392 ticks were collected on the surface of sheep,most of which were Hyalomma asiaticum(48.99%),All ticks collected from the environment were Hyalomma asiaticum,explained that Hyalomma asiaticum is the local dominant tick species.(2)Based on the investigation of tick distribution in Shanshan County,we chosed Hyalomma asiaticum as the study object,using r Has CPL as a candidate antigen for an anti-tick vaccine,the immune protective anti-tick test was carried out on local sheep in Shanshan county.After emulsifying purified r Has CPL with aluminum adjuvant,took sheep as a model,multipoint immunization(0.5m L/One)was performed subcutaneously on the neck of sheep.7,14,21,28,35,42,52,70,and 78 days after immunization,blood was collected from sheep jugular vein to isolate serum,the serum antibody level of sheep was detected by ELISA,Western blot was used to detect the serum reactivity of r Has CPL.On the 25 th day after the third immunization,infect Hyalomma asiaticum through the sheep ear,observe the anti-tick effect.The results showed that there were no stress response in sheep after immune with r Has CPL.ELISA results showed that On the 21 th day after the two immunization,antibody levels reached the highest level(1:2 5600),until day 42,Then antibody levels began to decline slowly.Western blot results showed that sheep polyclonal antibody serum can react specifically with r Has CPL.After infection Hyalomma asiaticum,the infested rates of 65% and engorge rate of 30.61% in the immune group were significantly lower than 75.83% and 75.47% in the control group;The mortality rate of the immune group was(24.17%)higher than that of the control group(13.33%).There were significant differences in Engorge weight,egg weight,and Egg incubation rate between the immune group and the control group(P<0.05).The results showed that,after immunizing sheep with r Has CPL,sheep produced specific anti r Has CPL antigen serum,the immune effect was 63.13%,these results indicate that r Has CPL has a certain protective effect on sheep.