Analysis on the survey data of the vulnerable population with epidemic hemorrhagic fever virus infection in Tianjin City

Objective The present study was conducted to affirm the vulnerable population with epidemic hemorrhagic fever vires infection (latent or obvious infection) in Tianjin City in 2005 in order to take relative measures to prevent and control the disease．Methods In this study，the se-lected vulnerable population with epidemic hemorrhagic fever included wastes purchasing persons，population around the epidemic spots，food-cooking workers and peasants．The control group was made up of researchers．According to the primary surveillance results (The positive rate of IgG an-tibody of EHF virus was 0.72％) of the population around epidemic spots in 2004，it was con-firmed that the sample size in each kind of population was not less than 140 samples (One posi-tive person was found at least．)．After the serum of each kind of population was collected，the specific IgG antibody of EHF virus in the serum was detected by Indirect Fluorescent Antibody test (IFA)．Then chi-square test was adopted to make statistical analysis．Results 14 cases with positive IgG antibody were found among the 546 key people，and the latent infection rate was 2.56％．But the latent infection rate of the wastes purchasing persons was 7.50％，which had sta-tistical significance of the difference comparing to that (0.79％) of the control group(researchers)(X2=5.473，PX2=O.544,P>0.05).The cases with latent infection among the vulnerable population had no difference of ages and sexes．Conclusion In Tianjin city，the wastes purchasing persons were the vulnerable population who were easy to infect epidemic hemorrhagic fever，and the population around the epidemic spots，food—cooking persons，and peasants belonged to the general population．