云南省腺鼠疫康复人群血清F1抗体流行病学调查

目的 了解云南省腺鼠疫康复人群血清F1抗体的水平分布和影响因素,为鼠疫防治提供理论依 据.方法 采用病例对照研究.以云南省1986-2005年的鼠疫监测资料为依据,设计调查表,确定调查地点和人群.采集云南省23个县的腺鼠疫康复人群血清248份作为病例组,采集7个县的有EV活菌疫苗接种史的健康人群血清295份作为人工免疫组,采集1个非疫区县的健康人群血清235份作为阴性对照组.用间接血凝试验进行检测.阳性判定标准为血清滴度≥1:20.结果 ①疫区F1抗体阳性率[22.10%(120/543)]与非疫区[0(0/235)]比较,差异有统计学意义(χ2=44.80,P<0.05).②病例组F1抗体阳性率为35.89%(89/248),抗体几何平均滴度(GMT)为1:84;人工免疫组阳性率为10.51%(31/295),GMT为1:34;阴性对照组235份均为阴性.病例组阳性率高于人工免疫组和阴性对照组,差异均有统计学意义(χ2值分别为50.41、103.39,P<0.0125);人工免疫组阳性率高于阴性对照组,差异有统计学意义(χ2=26.23,P<0.0125).③病例组间F1抗体阳性率在年龄、性别、民族、职业上的差异均无统计学意义(χ2值分别为1.88、2.01、5.46、0.04,P>0.05).④89名F1抗体阳性的腺鼠疫康复者发病时的血清滴度和康复后的滴度比较,差异无统计学意义(t=1.23,P>0.05).结论 ①云南省家鼠鼠疫疫源地人群鼠疫F1抗体阳性检出地均分布在疫区内,其地理分布与疫区分布相吻合.②自然感染鼠疫后.约有1/3的腺鼠疫康复人群能形成长期免疫,仍有2/3的人有再次感染的可能性,所形成的自然获得性免疫,其保护率和保护效果要好于接种EV活菌疫苗形成的人工获得性免疫.③人群感染鼠疫恢复后,F1抗体阳性检出率不受年龄、性别、民族、职业的影响.对于经过一定时间仍能检出F1抗体的部分腺鼠疫康复人群而言,时间的消长并不影响抗体滴度的变化,甚至能长期维持较高水平.

Serum epidemiological investigation of F1 antibody of population having healed from plague in Yunnan Province

Objective To provide theoretical and scientific evidences for plague control,through understanding the F1 antibody level distribution and affected factor of population having healed from plague from plague natural focus of Rat.flavipectus in Yunnan Province.Methods The places and population investigated were chosen according to plague surveillant data in Yunnan Province from 1986 to 2005,using caso-control study and quesfionary. All samples were detected by indirect hemagghtination(IHA),including 248 serum samples from population having heaIed from phsue in 23 counties as case group.295 senlm samples from healthy population inoculated with EV vaccine in 7 counties as artificial immunization group, and 235 serum samples from healthy population not inoculated it in a non-plagued foei county as negative comparison group,with the diagnosing standard for positive titor being not less than 1:20.Results(①The difference WSS statistically significant(X2=44.80,P<0.05)between plague and non-plagued foci with F1 antibody positive rates being 22.10%(120/543)and 0(0/235),respectively.② The F1 antibodv positive rate of case group,35.89%(89/248)and geometric mean titer(GMT)1:84,was higher than that of artiIicial immunization group,which was 10.51%(31/295)and with GMT 1:34,respectively,the difference being statistically significant(X2=50.41,P<0.0125);the positive rate of case group wgs hisher than the neganve comparison group,the difference being statistically significant(X2=103.39,P<0.0125):the posifive mte of artificial immunization group was higher than the negative comparison group,the difference being statisticallv significant(X2=26.23,P<0.0125).③The differences were not statistically significant in the F1 antibedy positive rates of case group for age,sex,nation and occupation(X2=1.88,2.01,5.46,0.04,P>0.05).④The difference was not statistically significant in 89 plague patients with positive F1 antibody at the time of onset and rehabilitation(t= 1.23,P>0.05).Conclusions ①Plague FI antibody in people distributes the sanle a8 the plague natural focus of Rat.flavipectus does in Yunnan Province.②For naturally infected plague patients,only 1/3 popuhtion get long- term immunity,and still 2/3 can be infected again.The protecting rate and effect of naturally acquired immunity due to infection of plague are better than amfieially acquired immunity from inoculation of EV vaccine.③For the population having healed from plague,the positive rotes of FI antibody are not affected by age,sex,nation and occupation,however for those whose plague F1 antibody is still positive after some time,the titer will remain or even increase.