Epidemiological Investigation Of Latent Tuberculosis Infection Among Key Populations In Rural Communities And Evaluation Of New Infection Detection Techniques

Background:Tuberculosis is a major public health threat that seriously threatens human health.It is estimated that nearly a quarter of the world’s population is infected with mycobacterium tuberculosis and remain in a state of latent infection for a long time,and 5%-10%of the latently infected people may develop active tuberculosis in their lifetime.Carrying out tuberculosis preventive treatment for high-risk populations with latent tuberculosis infection is one of the important means to achieve the strategic goal of ending the tuberculosis epidemic.However,at present,the burden of latent tuberculosis infection and its epidemic characteristics of key populations in rural communities in China have yet to be clarified,and it is urgent to establish a suitable and localized technical system for the detection and preventive intervention of latent tuberculosis infection.Methods:Based on the project "Immune Intervention Research on Latent Tuberculosis Infection among Key Populations in Rural Communities",this study carried out an epidemiological investigation of latent tuberculosis infection among key populations(middle-aged and elderly people aged 50-70 years,patients with diabetes mellitus)in rural communities in China,and obtained the burden and epidemic characteristics of latent tuberculosis infection in the target population,as well as the applicability evaluation of new latent tuberculosis infection detection technology,will provide data reference for further development of latent tuberculosis infection detection of key populations and community intervention in the future.On the basis of signed informed consent,the basic demographic information of the participants was first collected by questionnaire survey and routine physical examination.Chest imaging examination and questioning of suspicious symptoms were performed for each participant.Three sputum samples were collected from suspected tuberculosis patients or those with suspicious symptoms of tuberculosis for sputum smear,sputum culture and Gene-Xpert testing to rule out active tuberculosis.Use the interferon gamma release assay(IGRA)to obtain the burden of latent tuberculosis infection in the target population.The mycobacterium tuberculosis antigenbased skin test(TBST)was carried out,and the performance evaluation was carried out with the IGRA results as a reference,and the factors affecting the consistency of the two results were analyzed.Results:1)Epidemiological investigation of latent tuberculosis infection in middle-aged and elderly populations in rural communities and evaluation of new infection detection techniques.A total of 383 middle-aged and elderly people aged 50-70 years were included,and no active tuberculosis cases were found.The prevalence of latent tuberculosis infection based on IGRA results was 20.10%(77/383).In this key population,the positive rate of TBST(48 hours)was 11.75%(45/383),the consistency rate between TBST(48 hours)and IGRA results was 90.58%(346/382),and the Kappa coefficient was 0.65(95%CI:0.550.76).The results of multivariate logistic regression analysis showed that those with a history of smoking and close contact with tuberculosis had a higher risk of latent tuberculosis infection,with adjusted odds ratios of 4.33(95%CI:1.78-10.53)and 3.52(95%CI:1.08-11.45),respectively.2)Epidemiological investigation of latent tuberculosis infection in patients with diabetes mellitus in rural communities and evaluation of new infection detection techniques.A total of 468 patients with diabetes mellitus aged 18-65 years were included,among whom no active tuberculosis cases were found,and the prevalence of latent tuberculosis infection based on IGRA results was 15.38%(72/468).The positive rate of TBST was 10.68%(50/468),the consistency rate between TBST and IGRA results was 91.03%(426/468),and the Kappa coefficient was 0.61(95%CI:0.500.71).Repeated testing after a three-month interval,the positive rate of TBST was 15.84%(64/404),the consistency rate between TBST and the first IGRA detection results was 94.06%(380/404),and the Kappa coefficient was 0.77(95%CI:0.68-0.86).Conclusions:The study obtained the prevalence of latent tuberculosis infection based on IGRA results in middle-aged and elderly people and patients with diabetes mellitus.TBST and IGRA showed relatively good consistency in the study target population.It was found that the boosting effect of the skin test could improve the positive rate of TBST and the consistency with the results of IGRA.