Atmospheric nitrogen deposition promotes carbon loss from peat bogs

Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with important, but still unknown, effects on their C balance. Here we present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from approximately 0.2 to 2 g.m(-2).yr(-1). We found that enhanced decomposition rates for material accumulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decomposition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains about whether decay-resistant Sphagnum will continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.     

2016年长江中下游长江委水文机构工作区钉螺分布调查

目的掌握长江中下游长江水利委员会（长江委）所属水文机构工作区钉螺分布状况,为评估水文工作人员血 吸虫感染风险和制订防治对策提供科学依据。方法对上述水文机构工作区域的可疑环境采用系统抽样结合环境抽样 法进行查螺,对所得数据进行统计分析。结果共调查了17个水文机构的19处工作现场,查出9个水文机构的10处工 作现场有钉螺孳生。有螺面积查出比例达38.81%,活螺框出现率为3.08%,平均活螺密度为0.07只/0.1 m2,其中所处中 游的水文机构工作区的平均活螺密度和活螺框出现率最高。结论长江中下游长江委所属部分水文机构工作区域有不 同程度的钉螺孳生,水文工作人员面临血吸虫感染风险。     

Impact of environmental change and schistosomiasis transmission in the middle reaches of the Yangtze River following the Three Gorges construction project

With the construction of the Three Gorges high dam on the Yangtze River in China in mind, a serious of ecological environmental factors that might affect the transmission of Schistosoma japonicum in Jian Han Plain were investigated by means of data collection, field surveys and observation in Hubei Province. Several ecological factors including water level of the Yangtze River; riparian water table, annual rainfall and yearly evaporation were investigated in relation to the prevalence of schistosomiasis. The results suggest that after the dam construction, middle water level flows (ie between flood flows and dry-weather flows) will persist in the flood season due to a rise in the water table. The investigation indicated that snail distribution and human schistosomiasis prevalence differed significantly between years which had typically high, middle and low typical water levels in the Yangzte. Moreover, the prevalence of the disease showed a significant linear regression relationship with density of snail intermediate hosts, water table, annual rainfall, yearly evaporation and ground altitude in the survey area. Systematic and careful monitoring and surveillance is necessary to investigate the impact of the environmental changes brought about by the dam construction on schistosomiasis transmission.     

武夷山中段闽江流域淡水蟹类种群及并殖吸虫感染调查

目的　调查武夷山中段闽江流域并殖吸虫中间宿主蟹类种群及其感染情况,为寄生虫病防治研究和寄生虫资源库样本扩充提供基础资料。方法　2020年11月—2021年4月,在武夷山山脉沙溪和富屯溪闽江水系的建宁县及其周边宁化、邵武、将乐、顺昌县开展调查,选择居民区附近山涧水沟采集溪蟹标本。根据雄蟹第一腹肢末节形态特征进行蟹种鉴定,采用直接压片法、双筛法检测捕获的溪蟹并殖吸虫感染。分离并殖吸虫囊蚴,根据囊蚴大小、囊壁厚薄和排泄囊及肠管形态鉴定囊蚴种类,并计算溪蟹囊蚴感染率、感染度和感染指数。结果　建宁县及周边闽江流域6条水系存在将乐华溪蟹、福建华溪蟹、黎川华南溪蟹、林氏华南溪蟹、沈氏华南溪蟹、平肢华南溪蟹、恩氏博特溪蟹等7种溪蟹分布,在蟹体内检出卫氏并殖吸虫、斯氏并殖吸虫和三平正并殖吸虫囊蚴,并殖吸虫囊蚴感染率为43.6%（125/287）。将乐华溪蟹卫氏并殖吸虫、三平正并殖吸虫、斯氏并殖吸虫囊蚴感染率分别为57.1%（48/84）、26.2%（22/84）、61.8%（21/34）;福建华溪蟹卫氏并殖吸虫、三平正并殖吸虫囊蚴感染率分别为52.6%（51/97）和30.9%（30/97）;黎川华南溪蟹卫氏并殖吸虫囊蚴感染率为6.9%（5/72）,此为该蟹卫氏并殖吸虫感染首次记录。建宁县调查点溪蟹多为卫氏并殖吸虫和三平正并殖吸虫囊蚴混合感染,并殖吸虫感染率为70.4%（76/108）,平均每只感染溪蟹检出囊蚴15.3个、平均每克溪蟹检出囊蚴1.9个,囊蚴感染指数为20.5。建宁县周边调查点溪蟹体内检出卫氏并殖吸虫、三平正并殖吸虫和斯氏并殖吸虫囊蚴,溪蟹并殖吸虫囊蚴感染率为52.3%（56/107）,平均每只感染溪蟹检出囊蚴9.8个、平均每克溪蟹检出囊蚴0.9个,囊蚴感染指数为4.6。结论　建宁县及周边闽江流域蟹类种群资源丰富,且并殖吸虫囊蚴感染率高,为高度感染风险的并殖吸虫病自然疫源地。     

南水北调中线引江济汉工程对血吸虫病传播风险评估及干预措施

目的评价南水北调中线引江济汉水利工程可能对血吸虫病传播造成的风险,提出工程建设中控制血吸虫病传播的干预措施。方法搜集工程建设相关资料,调查工程区3个县(市、区)近年血吸虫病疫情,并在工程取水口现场开展漂浮物观测实验与船只携带钉螺现场调查。结果在引江济汉水利工程区存在引水、输水、供水及航运等引起钉螺扩散的4大风险因素。针对这些风险因素,提出了渠道硬化、增设沉螺池和拦漂网或筛孔墙、规范有螺区的取土处理、以及加强工程区监测等减少血吸虫病传播风险的防治对策和措施。结论虽然引江济汉工程建设存在可能引起或增加血吸虫病传播的风险因素,但只要在工程建设中采取相应的干预措施,可将风险降到最低限度。     

Occurrence of Hirudinea in the lakes Nisko and Urad with special reference to Piscicola geometra (L.)]

By the method of hand fishing 1886 leeches from 13 species were obtained, but by the net 3422 fishes with 798 specimens of P. geometra and 16 H. marginata were caught. P. geometra was classified as the eudominant and eurozooic. In dark phase of day the intensity and extensity of infection was higher than in the afternoon and morning hours.     

Piscicola brylinskae, a new leech species from the Netherlands (Hirudinea: Piscicolidae)

Piscicola brylinskae n. sp. is described from the lake Vechten in the village of Bunnik (Prov. Utrecht), The Netherlands. The characteristic features of this leeches allow to conclude that this species is a member of the subfamily Piscicolinae, probably a parasite of fish.     

Bionomics studies of Mansonia mosquitoes inhabiting the peat swamp forest

The present study was conducted in the years 2000-2002 to determine the bionomics of Mansonia mosquitoes, vectors of nocturnally subperiodic Brugia malayi, inhabiting the peat swamp forest, "Phru Toh Daeng", Narathiwat Province, Thailand. Fifty-four species of mosquitoes belonging to 12 genera were added, for the first time, to the list of animal fauna in the peat swamp forest. Mansonia mosquitoes were the most abundant (60-70%) by all collection methods and occurred throughout the year with a high biting density (10.5-57.8 bites per person-hour). Ma. bonneae was most prevalent (47.5%) and fed on a variety of animal hosts, including domestic cats, cows, monkeys, and man with a maximum biting density of 24.3 bites per person-hour in October. The infective bites were found for the first time in Ma. annulata collected at Ban Toh Daeng (13 00-14 00 hours) and also Ma. bonneae at forest shade (16 00-17 00 hours) and in a village (20 00-21 00 hours) with rates of 0.6, 1.1 and 1.0%, respectively. The biting activities of these two species occurred in both the day and night time, with two lower peaks at 10 00 hours (18.5 bites per person-hour) and 13 00-15 00 (8.5-10.0 bites per person-hour) hours, but the highest peak was 19 00-21 00 hours (31.5-33.0 bites per person-hour) The biting activity patterns corresponded with the periodicity found in man and domestic cats and may play an important role in either transmission or maintenance of the filarial parasites in the peat swamp forest. The relative role of Ma. bonneae and Ma. uniformis in different environmental settings (primary swamp forest and open swamp) on the transmission of nocturnally subperiodic B. malayi merits further study.     

四所中学初中生结核菌素反应性调查

目的了解当地初中生结核菌素反应状况。方法选医院驻地怀来县4所中学5153名初一年级学生进行标准化PPD试验调查，并对学生年龄、性别、居住来源及结核病流行特点进行调查分析。结果80.2%的学生集中在13～14岁组，来源于农村者占57.6%，≥5mm总阳性反应率23.1%，≥15mm为7.4%。2219名无卡痕学生PPD反应在≥5mm，≥10mm，≥15mm和≥20mm分别为16.0%、10.9%、5.9%和2.9%，有卡痕学生结素反应性明显高于无卡痕者；有结核接触史和既往史学生的结素反应均高于无结核接触史和既往史者。结论把初中新入学学生作为当地结素试验对象，建议将≥15mm结素反应者列为预防性治疗对象,以减少结核病发生。     

The role of eye-like spots of parasitic leeches (Hirudinea, Piscicolidae) in searching for fish-hosts

Piscicola geometra (L.), Piscicola respirans Troschel, 1850, and Caspiobdella fadejewi (Epshtein, 1968) find their hosts (fishes) by reacting to their shadow. Eye-like spots whose number ranges from 8 to 16 depending on a species, located on the posterior sucker are the main receptors perceiving the decrease in light intensity and thus enabling an immedaite reaction to the host's shadow. They are distributed on the perimeter of the sucker, are absent only from the section that is constantly shaded by the leech body. Experiments with a simulated shadow reveled considerable differences in the threshold light doses between the studied species: P. geometra - 12 lux, P. resprans - 4 lux and C. fadejewi - 2.5 lux. Below these values the leeches do not perceive the decrease in light intensity and do not make host-searching movements. The smallest decreases in light intensity, at which the leeches still make host-searching movement, are: P. geometra - 5 lux, P. resprans - 2 lux, and C. fadejewi- 1.5 lux. In case of P. respirans and C. fadejewi such small decreases in light intensity (2 - 1.5 lux) may be caused only by small fishes which, according to the results of the experiment, should not be infested. This is confirmed by field observations - small fishes are mostly free from parasites. Large fishes (casting a large shadow) have much more numerous leeches.