目的 了解福建省部分地区寄生蜱中山羊无形体的流行情况及其遗传进化特征。方法 于2011—2024年在宁德市的柘荣县、周宁县、福安市、霞浦县和南平市的浦城县、邵武市共6个县（市）收集动物（鼠、山麂、犬、山羊、野兔、牛、野猪、猪）体表寄生蜱，经形态学和分子生物学鉴定后，提取蜱DNA，采用巢式PCR扩增山羊无形体柠檬酸合成酶基因（gltA）片段，PCR阳性产物测序后在美国国家生物技术信息中心（NCBI）进行BLAST初步比对。通过MEGA11软件比对后采用邻接法构建系统进化树。使用DNASP V6.0软件计算山羊无形体gltA基因序列遗传多样性指标，用Arlequinv3.5.2.2进行不同地区的序列分组并通过Popart v1.7绘制单倍型网络图。率的比较采用χ²检验和Fisher确切概率法，影响因素分析采用多因素logistic回归。结果 共收集并检测了650只蜱。不同宿主中，山麂体表寄生蜱山羊无形体感染率最高（19.11%，30/157），其次为牛体表寄生蜱（2/13），不同宿主寄生蜱的山羊无形体感染率差异有统计学意义（χ² = 59.64，P < 0.01）。检获的蜱主要以成蜱为主，其次为若蜱。若蜱感染率最高（15.38%，8/52），成蜱次之（4.88%，29/594），幼蜱（0/2）和卵（0/2）未检出，蜱不同发育期感染率差异有统计学意义（χ² = 9.15，P < 0.05）。雌、雄成蜱感染率分别为7.99%（27/338）、0.78%（2/256）（χ² = 16.29，P < 0.01）。宁德市柘荣县、周宁县、福安市、霞浦县蜱的山羊无形体感染率分别为5.68%（5/88）、11.06%（23/208）、0/7、0/7，南平市浦城县、邵武市感染率分别为2.69%（9/335）、0/5，不同地区间感染率差异有统计学意义（χ² = 15.74，P < 0.01）。夏季、秋季、冬季、春季蜱山羊无形体感染率分别为4.64%（7/151）、4.37%（9/206）、7.34%（21/286）、0/7（χ² = 2.86，P > 0.05）。650只蜱分属5属14种，山羊无形体总阳性率为5.69%（37/650）。在7个蜱种中检出山羊无形体，卵形硬蜱感染率最高（42.86%，12/28），福建省待定血蜱次之（31.58%，12/38），不同蜱种感染率差异有统计学意义（χ² = 83.16，P < 0.01）。多因素分析结果显示，与成蜱相比，若蜱感染山羊无形体的风险性显著增加（OR = 2.83，95% CI：1.15~6.94）。与宁德市相比，南平市感染风险性降低（OR = 0.20，95% CI：0.08~0.50）。BLAST结果显示，37条测序序列与山羊无形体参考序列（GenBank登录号：OQ847085.1）一致性最高，为97.88%~98.92%。系统进化树结果显示，本研究序列与青海省的山羊无形体亲缘关系最近。福建省部分地区山羊无形体序列共有15个单倍型（Hap），总体单倍型多样性指数为0.88，总体核苷酸多样性为0.009，Hap1~Hap3为优势单倍型。结论 福建省部分地区寄生蜱山羊无形体感染率较高，需加强蜱传病原体监测及防控。

Objective To investigate the prevalence and genetic evolutionary characteristics of Anaplasma capra in parasitic ticks in selected regions of Fujian Province. Methods Parasitic ticks were collected from domestic and wild animals (including murine, muntjacs, dogs, goats, hares, cattle, wild boars, and pigs) in Zherong County, Zhouning County, Fu’an City and Xiapu County of Ningde City and Pucheng County and Shaowu City of Nanping City from 2011 to 2024. Following morphological and molecular biological identification, genomic DNA was extracted from ticks and A. capra citratesynthase gene (gltA) gene was amplified using nested PCR assay. Positive PCR amplification products were sequenced and initially aligned by BLAST on National Center for Biotechnology Information (NCBI). Sequence alignment was performed using the software MEGA 11, and a phylogenetic tree was created using with the neighbor-joining method. Genetic diversity indices of A. capra gltA gene sequence were calculated using the software DnaSP 6.0, and a haplotype network was constructed using the software PopArt 1.7 after grouping sequences by region using the software Arlequin 3.5.2.2. Comparisons of proportions were done with chi-square test and Fisher’s exact test, and influencing factors were identified using a multivariate logistic regression model. Results A total of 650 ticks were tested, with the highest prevalence of A. capra infection on the muntjac body surface (19.11%, 30/157), followed by on cattle body surface 2/13, and there was a significant difference in the prevalence of A. capra infection in different hosts (χ² = 59.64, P < 0.01). The captured ticks were mainly adults, followed by nymphs. The highest prevalence of A. capra infection was detected in nymphs (15.38%, 8/52), followed by in adults (4.88%, 29/594), with no A. capra infection seen in larval ticks (0/2) or eggs (0/2), and there was no significant difference in the prevalence of A. capra infection in ticks at different developmental stages (χ² = 9.15, P < 0.05). The prevalence of A. capra infection was 7.99% (27/338) and 0.78% (2/256) in female and male adult ticks (χ² = 16.29, P < 0.01). The prevalence of A. capra infection was 5.86% (5/88) in ticks from Zherong County, 11.06% (23/208) in Zhouning County, 0/7 in Fu’an City and 0/7 in Xiapu County of Ningde City and 2.69% (9/335) in Pucheng County and 0/5 in Shaowu City of Nanping City, and there was no region-specific prevalence found (χ² = 15.74, P < 0.01). The prevalence of A. capra infection was 4.64% (7/151) in ticks sampled in summer, and 4.37% (9/206) in autumn, 7.34% (21/286) in winter, and no infection was detected in ticks sampled in spring (0/7) (χ² = 2.86, P > 0.05). Six hundred fifty ticks belonged to 14 species of 5 genera, and the overall prevalence of A. capra infection was 5.69% (37/650) in ticks. A. capra was detected in 7 tick species, with the highest prevalence in Ixodes ovatu (42.86%, 12/28), followed by in Haemaphysalis of unknown species in Fujian Province (31.58%, 12/38) (χ² = 83.16, P < 0.01). Multivariate analysis showed a significantly higher risk of A. capra infection in tick nymphs than in adult ticks (OR = 2.83, 95% CI: 1.15 to 6.94), and a lower risk of A. capra infection was seen in ticks from Nanping City than from Ningdu City (OR = 0.20, 95% CI: 0.08 to 0.50). BLAST analysis showed that the 37 sequences shared 97.88% to 98.92% identity with the A. capra reference sequence (GenBank accession number: OQ847085.1). Phylogenetic analysis revealed that the A. capra sequences from this study shared the closest relationship with sequences of A. capra from Qinghai Province. A total of 15 haplotypes were identified in sequences of A. capra from selected regions of Fujian Province, with overall haplotype diversity of 0.88 and nucleotide diversity of 0.009, and Hap1 to Hap3 were dominant haplotypes. Conclusion The prevalence of A. capra infection is high in parasitic ticks in selected regions of Fujian Province. Surveillance and management of tick-borne pathogens are recommended to be intensified.