山东省烟台市长角血蜱携带嗜吞噬细胞无形体调查研究

An investigation of Anaplasma phagocytophilum carried by Haemaphysalis longicornis in Yantai,Shandong Province,China

目的了解山东省烟台市长角血蜱携带嗜吞噬细胞无形体的情况,为烟台市防控人粒细胞无形体病、降低蜱危害提供相关科学依据。方法于2021年4-10月在烟台市牟平区、开发区、蓬莱区、海阳市、栖霞市、招远市、莱州市等地开展蜱监测,采用体表检蜱法和布旗法分别采集家畜体表的寄生蜱和野外环境中的游离蜱。采用巢式PCR法对采集的长角血蜱进行嗜吞噬细胞无形体检测,SPSS 22.0软件对不同组间阳性率进行χ2检验。结果共捕获1698只蜱,均为长角血蜱,其中寄生蜱1097只,游离蜱601只。将采集的913只寄生蜱与游离蜱按不同地区、不同来源和发育阶段及有无吸血进行分组,提取DNA,获得413份样本,共检出13份嗜吞噬细胞无形体核酸阳性样本,阳性检出率为3.15%,最小感染率1.42%;其中寄生蜱检测出11份阳性样本,包括2份犬源蜱样本和9份羊源蜱样本;游离蜱检测出2份阳性样本。寄生蜱阳性样本均为成蜱,游离蜱阳性样本中,1份为幼蜱,1份为成蜱;不同来源蜱样本阳性率的差异无统计学意义(χ^(2)=1.722,P=0.423)。开发区、莱州市寄生蜱中分别检出3份和6份阳性样本,蓬莱区游离蜱中检出1份阳性样本,招远市则在2份寄生蜱和1份游离蜱样本中检出阳性,不同市(区)之间蜱样本阳性率的差异有统计学意义(χ^(2)=11.468,P=0.038)。结论长角血蜱作为烟台市的优势蜱种,且多个市(区)不同来源的长角血蜱存在嗜吞噬细胞无形体感染,潜在致病风险较高,应加强蜱生态学监测及相关病原体检测,为人粒细胞无形体病防控提供科学依据。

Objective To investigate the prevalence of Anaplasma phagocytophilum in Haemaphysalis longicornis in Yantai,Shandong Province,China,so as to provide a scientific basis for the prevention and control of human granulocytic anaplasmosis and the dangers of ticks in Yantai.Methods Tick surveillance was carried out in Muping District,Yantai economic and technological development zone(development zone),Penglai District,Haiyang City,Qixia City,Zhaoyuan City,and Laizhou City of Yantai from April to October in 2021.On-host ticks were collected from domestic animals through body surface inspection and questing ticks in the field environment were collected using the flagging method.Nested PCR was used to detect A.phagocytophilum in H.longicornis specimens.SPSS 22.0 software was used to perform the Chi-square test to compare the positive rates of different groups.Results A total of 1698 ticks(1097 on-host ticks and 601 questing ticks)were captured,all belonging to H.longicornis.DNA was extracted from 913 ticks grouped by region,source,developmental stage,and whether they were engorged.Among the obtained 413 DNA samples,13 were positive for the nucleic acid of A.phagocytophilum,with a positive rate of 3.15%and a minimum infection rate of 1.42%;and of the 13 positive samples,11 were from adult on-host ticks(2 from dogs and 9 from sheep),and the other 2 were from questing ticks(1 from larvae and 1 from adults).There was no significant difference in the positive rates of ticks from different hosts(χ^(2)=1.722,P=0.423).By region,3 and 6 positive samples were detected in the on-host ticks in the development zone and Laizhou City,1 positive sample was detected in the free ticks in Penglai District,and 3 positive samples(2 from on-host ticks and 1 from free ticks)were detected in Zhaoyuan City.There was a significant difference in the positive rates of ticks from different regions(χ^(2)=11.468,P=0.038).Conclusions H.longicornis,the dominant tick species in Yantai,from different host sources in various districts/cities have an infection with A.phagocytophilum,indicating a high pathogenic risk from human granulocytic anaplasmosis.Tick surveillance and pathogen detection should be strengthened to inform the prevention and control of human granulocytic anaplasmosis.