Abstract: Objective　To investigate the prevalence of Schistosoma japonicum infections in wild rodents in schistosomiasis⁃endemic areas of China, so as to provide insights into formulation of technical guidelines for monitoring of and the precise control strategy for S. japonicum infections in wild rodents during the elimination phase. Methods　Two administrative villages where schistosomiasis was historically highly prevalent were selected each from Dongzhi County, Anhui Province, and Duchang County, Jiangxi Province as study villages. Wild rodents were captured from study villages with baited traps or cages at night in June and September, 2021. The number of rodents captured was recorded, and the rodent species was characterized based on morphological characteristics. Liver tissues were sampled from captured rodents for macroscopical observation of the presence of egg granulomas, and S. japonicum infection was detected simultaneously using liver tissue homogenate microscopy, examinations of mesenteric tissues for parasites, and modified Kato⁃Katz thick smear technique (Kato⁃Katz technique). A positive S. japonicum infection was defined as detection of S. japonicum eggs or adult worms by any of these methods. The rate of wild rodent capture and prevalence of S. japonicum infections in wild rodents were compared in different study villages and at different time periods, and the detection of S. japonicum infections in wild rodents was compared by different assays. Results The overall rate of wild rodent capture was 8.28% (237/2 861) in Dongzhi County, and the wild rodent capture rates were 9.24% (133/1 439) and 7.31% (104/1 422) in two study villages ([χ2] = 3.503, P = 0.061), and were 8.59% (121/1 409) and 7.99% (116/1 452) in June and September, 2021, respectively ([χ2] = 0.337, P = 0.561). The overall rate of wild rodent capture was 3.72% (77/2 072) in Duchang County, and the wild rodent capture rates were 6.91% (67/970) and 0.91% (10/1 102) in two study villages ([χ2] = 51.901, P < 0.001), and were 4.13% (39/945) and 3.37% (38/1 127) in June and September, 2021, respectively ([χ2] = 0.815, P = 0.365). Rattus norvegicus was the predominant rodent species captured in both counties, accounting for 70.04% (166/237) of all captured wild rodents in Dongzhi County and 88.31% (68/77) in Duchang County. No S. japonicum infection was detected in wild rodents captured in Duchang County. Nevertheless, the overall prevalence of S. japonicum infections was 51.05% (121/237) in wild rodents captured in Dongzhi County, with prevalence rates of 50.38% (67/133) and 51.92% (54/104) in two study villages ([χ2] = 0.098, P = 0.755), and 54.31% (63/116) and 47.93% (58/121) in September and June, 2021, respectively ([χ2] = 0.964, P = 0.326). Of 237 wild rodents captured in Dongzhi County, there were 140 (59.07%) rodents with visible hepatic egg granulomas, 117 (49.47%) tested positive for S. japonicum eggs by liver tissue homogenate microscopy, 34 (14.35%) tested positive for S. japonicum eggs with Kato⁃Katz technique; however, no adult S. japonicum worms were detected in mesenteric tissues. In addition, hepatic egg granulomas were found in all wild rodents tested positive for S. japonicum eggs with liver tissue homogenate microscopy.  Conclusions　The rate of wild rodent capture and prevalence of S. japonicum infection in wild rodents vary greatly in schistosomiasis⁃endemic areas of China, and the prevalence of S. japonicum infection is slightly higher in wild rodents captured in autumn than in summer. Liver tissue is recommended as the preferred sample for surveillance of S. japonicum infection in wild rodents, and a combination of macroscopical observation of hepatic egg granulomas and liver tissue homogenate microscopy may be a standard method for surveillance of S. japonicum infection in wild rodents.  

Key words: Schistosoma japonicum, Elimination, Wild rodent, Egg granuloma, Dongzhi County, Duchang County 

摘要： 目的　了解我国血吸虫病流行区野鼠血吸虫感染率，为制定消除阶段野鼠血吸虫感染监测技术规范以及精准防控策略提供依据。方法　在安徽省东至县和江西省都昌县各选择2个历史血吸虫病疫情较重的行政村作为调查村，分别于2021年6月和9月采用夹（笼）夜法捕捉野鼠，统计野鼠捕获数量，采用形态学方法鉴定鼠种。捕获的野鼠剖杀后，取野鼠肝脏，肉眼观察其表面是否有虫卵结节；随后采用肝脏组织匀浆镜检法、肠系膜组织血吸虫虫体检查法和改良加藤厚涂片（Kato⁃Katz）法对野鼠血吸虫感染情况进行平行检测，任一方法检出血吸虫虫卵或虫体则判定为血吸虫感染阳性。比较不同调查村、调查时间野鼠捕获率、血吸虫感染率及不同方法对野鼠血吸虫感染检出率的差异。结果　安徽省东至县野鼠捕获率为8.28%（237/2 861）；2个调查村野鼠捕获率分别为9.24%（133/1 439）和7.31%（104/1 422），差异无统计学意义（[χ2]  = 3.503，P = 0.061）；2021年6月和9月野鼠捕获率分别为8.59%（121/1 409）和7.99%（116/1 452），差异无统计学意义（[χ2] = 0.337，P = 0.561）。江西省都昌县野鼠捕获率为3.72%（77/2 072）；2个调查村野鼠捕获率分别为6.91%（67/970）和0.91%（10/1 102），差异有统计学意义（[χ2] = 51.901，P < 0.001)；2021年6月和9月野鼠捕获率分别为4.13%（39/945）和3.37%（38/1 127），差异无统计学意义（[χ2] = 0.815，P = 0.365)。两县捕获野鼠均以褐家鼠为主，其中东至县捕获褐家鼠占捕获野鼠总数的70.04%（166/237）、都昌县占88.31%（68/77）。都昌县捕获野鼠未发现血吸虫感染阳性野鼠。东至县捕获野鼠的血吸虫感染率为51.05%（121/237）；2个调查村野鼠血吸虫感染率分别为50.38%（67/133）和51.92%（54/104），差异无统计学意义（[χ2] = 0.098，P = 0.755）；2021年9月捕获的野鼠血吸虫感染率（54.31%，63/116）略高于6月（47.93%，58/121），差异无统计学意义（[χ2]  = 0.964，P = 0.326）。此外，在东至县捕获的237只野鼠中，140只（59.07%）发现肝脏虫卵结节、117只（49.47%）肝脏组织匀浆镜检发现血吸虫虫卵、34只（14.35%）粪便Kato⁃Katz法检出血吸虫虫卵，但肠系膜组织检查均未发现血吸虫虫体；所有肝脏组织匀浆镜检检出血吸虫虫卵的野鼠均发现存在肝脏虫卵结节。结论　我国不同血吸虫病流行区野鼠捕获率及野鼠血吸虫感染率差异较大，秋季捕获的野鼠血吸虫感染率略高于夏季。肝脏样本可作为野鼠血吸虫感染监测的首选样本，肝脏虫卵结节观察法结合肝脏组织匀浆镜检法可作为监测的标准方法。

关键词: 日本血吸虫, 消除, 野鼠, 虫卵肉芽肿, 东至县, 都昌县