ABSTRACT
Objective To understand the level and distribution of antibody F1 against plague in population of Ningxia natural plague foci in 2007 and 2008. Methods Seven hundred and eighteen blood samples were collected in five major cities and counties of natural plague foci, and 475 blood samples were collected in nonplague area as control group. Conventional indirect hemagglutination, colloidal gold test, and enzyme-linked immunoassay were employed to test the antibody. If the result was tested positive by more than two methods used then the result was defined as positive. Antibody titer that did not reach the positive standard was defined as suspected samples. Results A total of 718 serum samples were tested, the results showed that 9 samples were positive (antibody titer was 1:16 - 1:64), the positive rate was 1.25%(9/718), suspected samples was 28, the detection rate was 3.90%(28/718). Four hundred and seventy-five serum samples in the non-plague area were all negative by the three methods. There was a significant difference of antibody F1 positive rate between residents in historical epidemic area and history nonepidemic area(χ2 = 4.44, P< 0.05). There was no statistical significance of the positive rate[1.25%(9/718), 1.25%(9/718),2.51%(18/718)]among the three methods used(χ2 = 1.91, P> 0.05). Conclusion There still exists a certain proportion of Fl antibody positive people in Ningxia natural plague foci, and these people are distributed in areas where several animal plague prevalent in recent years.