2015—2020年山西省阳泉市犬源型内脏利什曼病疫情调查

Prevalence of mountain-zoonotic type visceral leishmaniasis in Yangquan City of Shanxi Province from 2015 to 2020

目的 分析2015—2020年山西省阳泉市犬源型内脏利什曼病(mountain-type zoonotic visceral leishmaniasis, MTZVL)疫情,为当地制订内脏利什曼病防控策略提供科学依据。方法 收集2015—2020年阳泉市MT-ZVL病例特征并进行描述性统计分析;建立Joinpoint回归模型,通过计算年度变化百分比(annual percent change, APC)分析2015—2020年阳泉市MT-ZVL发病趋势变化。收集2020年阳泉市白蛉监测数据及犬利什曼原虫感染率调查数据,计算各县(区)白蛉密度和犬血清抗利什曼原虫抗体阳性率,并应用直线相关法分析其与人群MT-ZVL发病率间的相关性。结果 2015—2020年山西省阳泉市累计报告MT-ZVL病例162例,年均发病率1.9/10万,逐年报告病例数分别为4、7、16、27、33例和75例,呈快速上升态势(APC=72.79%,t=11.10,P <0.01)。阳泉市下辖5个县(区)均有MT-ZVL病例报告,病例主要分布于郊区(35.2%,57/162)和平定县(33.3%,54/162),年龄以≥15岁(71.6%,116/162)和0~2岁(22.2%,36/162)为主,职业以农民(37.4%,61/162)和散居儿童(24.5%,40/162)为主。2020年5—9月,阳泉市中华白蛉平均密度为6.3只/(灯·夜),其中郊区最高[12.6只/(灯·夜)]、盂县最低[1.1只/(灯·夜)],各县(区)中华白蛉平均密度差异有统计学意义(H=17.282,P <0.01)。全市家犬血清抗利什曼原虫抗体阳性率为7.4%(2 996/40 573),其中郊区最高(16.6%,1 444/8 677)、盂县最低(2.3%,266/11 501),各县(区)家犬血清抗利什曼原虫抗体阳性率差异有统计学意义(χ~2=1 753.74,P <0.01);流浪犬血清抗利什曼原虫抗体阳性率20.0%(159/794),高于家犬(χ~2=176.63,P <0.01)。白蛉密度、家犬血清抗利什曼原虫抗体阳性率和人群MT-ZVL发病率间均存在相关性(r=0.832~0.870,P均<0.05)。结论 2015—2020年山西省阳泉市MT-ZVL疫情呈快速上升趋势,亟需采取系统干预措施。

ObjectiveTo investigate the prevalence of mountain-type zoonotic visceral leishmaniasis(MT-ZVL) in Yangquan City, Shanxi Province from 2015 to 2020, so as to provide the scientific evidence for formulating the MT-ZVL control strategy.MethodsThe epidemiological data pertaining to MT-ZVL cases in Yangquan City from 2015 to 2020 were collected and descriptively analyzed. A Joinpoint regression model was created to analyze the trend in the MT-ZVL incidence in Yangquan City from 2015 to 2020 using annual percent change(APC). The sandflies surveillance data and the prevalence of Leishmania infections in dogs were collected in Yangquan City in 2020, and the regional distribution of sandflies density and sero-prevalence of Leishmania infections in dogs were calculated. In addition, the associations of sandflies density and sero-prevalence of Leishmania infections in dogs with the incidence of human MT-ZVL were examined using the linear correlation analysis.ResultsA total of 162 MT-ZVL cases were reported in Yangquan City, Shanxi Province from 2015 to 2020, with annual mean incidence of1.9/105, and there were 4, 7, 16, 27, 33 cases and 75 cases with MT-ZVL reported from 2015 to 2020, appearing a tendency towards a rapid rise(APC = 72.79%, t = 11.10, P < 0.01). MT-ZVL cases were reported across the five counties(districts) of Yangquan City, and the cases predominantly occurred in Jiaoqu District(35.2%, 57/162) and Pingding County(33.3%, 54/162).MT-ZVL cases were predominantly detected in residents at ages of 15 years and older(71.6%, 116/162) and at ages of 0 to 2years(22.2%, 36/162), with farmers(37.4%, 61/162) and diaspora children(24.5%, 40/162) as predominant occupations. The mean density of Phlebotomus chinensis was 6.3 sandflies per trap per night in Yangquan City from during the period from May to September, 2020, with the highest density observed in Jiaoqu District(12.6 sandflies per trap per night) and the lowest in Yuxian County(1.1 sandflies per trap per night), and there was a region-specific mean density of Ph. chinensis in Yangquan City(H =17.282, P < 0.01). The sero-prevalence of serum anti-Leishmania antibody was 7.4%(2 996/40 573) in domestic dogs in Yangquan City, with the highest sero-prevalence seen in Jiaoqu District(16.6%, 1 444/8 677), and the lowest in Yuxian County(2.3%, 266/11 501), and there was a region-specific sero-prevalence rate of anti-Leishmania antibody in domestic dogs in Yangquan City(χ~2= 1 753.74, P < 0.01). The sero-prevalence of anti-Leishmania antibody was significantly higher in stray dogs(20.0%, 159/794) than in domestic dogs(χ~2= 176.63, P < 0.01). In addition, there were significant associations among the sandflies density, sero-prevalence of anti-Leishmania antibody in domestic dogs and the incidence of human MT-ZVL(r = 0.832 to0.870, all P values < 0.05).ConclusionThe prevalence of MT-ZVL appeared a tendency towards a rapid rise in Yangquan City from 2015 to 2020, and systematic interventions are urgently needed for MT-ZVL control.