Specific detection of Angiostrongylus cantonensis in the snail Achatina fulica using a loop-mediated isothermal amplification (LAMP) assay

Angiostrongylus cantonensis, a rat lungworm, can cause eosinophilic meningitis and angiostrongyliasis in humans following ingestion of contaminated foods or intermediate/paratenic hosts with infective larvae. The snail Achatina fulica is one of the important intermediate hosts of A. cantonensis and is commonly eaten by humans in some countries. In the present study, we developed a loop-mediated isothermal amplification (LAMP) method for the specific detection of A. cantonensis in Ac. fulica. Primers for LAMP were designed based on the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA (rDNA) of A. cantonensis. Specificity tests showed that only the products of A. cantonensis were detected when DNA samples of A. cantonensis and the heterologous control samples Anisakis simplex s.s, Trichuris trichiura, Toxocara canis, Trichinella spiralis and Ascaris lumbricoides were amplified by LAMP. Sensitivity evaluation indicated that the LAMP assay is 10 times more sensitive than the conventional polymerase chain reaction (PCR) assay. The established LAMP assay is rapid, inexpensive and easy to be performed. It can be used in clinical applications for rapid and sensitive detection of A. cantonensis in snails, which has implications for the effective control of angiostrongyliasis.     

褐云玛瑙螺中枢内支配大触角肌肉神经元的分布

实验用荧光素Ｂｂ逆行追踪方法，研究了褐云玛瑙螺支配大触角肌肉活动的神经元在中枢的分布，结果表明，Ｂｂ标记神经元大多分布于同侧脑节，少量分布于侧脑节，同侧口球节，足节和侧节，Ｂｂ标记神经元大多为中小型神经元，个别属于大型神经元。     

中国大陆首例广州管圆线虫病区流行病学的调查

本文报告1984年10月在广东省徐闻县友好农场首例广州管圆线虫病区进行的流行病学调查。家鼠、褐云玛瑙螺、足襞蛞蝓、黑眶蟾蜍的感染率分别为28.57%(4/14)、33.83%(158/467)、29.19%(54/185)、4.76%(2/42)。并对徐闻县地理概况和人群进行了调查(生活习惯、卫生习惯、病史回顾、血涂片检查末梢血液嗜酸性粒细胞)。对于人群感染不多的原因,作者从感染途径(皮肤感染)、感染方式(食螺方式)进行了探讨。本调查资料为当地群众防治本病提供资料。     

褐云玛瑙螺(Achatina fulica Ferussac)中枢神经系统儿茶酚胺类神经元的分布

本文用乙醛酸诱发荧光组化法对褐云玛瑙螺中枢神经系统儿茶酚胺类神经元分布进行了观察。数百个儿茶酚胺类神经元对称性地分布于左、右口球神经节、脑神经节和足神经节内,而它们的轴突纤维则广泛分布于中枢神经系统所有的神经节内。这些儿茶酚胺类神经元大多为小型神经元,胞体直径10～24μm,少数为中、大型神经元,胞体直径40～60μm。     

Neuroeffector Connections of Giant Multimodal Neurons in the African Snail <Emphasis Type="Italic">Achatina Fulica</Emphasis>

A new method of making preparations was used to analyse the neuroeffector connections of the paired giant neurons of the African snail Achatina fulica. These neurons were found to induce postsynaptic potentials in the muscles of the mantle, heart, the wall of the pulmonary cavity, and the muscular elements of the renal complex, the pericardium, the sexual apparatus, the walls of the cerebral arteries, the filaments of the columellar muscles, the wall of the abdomen, and the tentacle retractor muscles. Rhythmic neuron activity led to the development of marked facilitation and long-term potentiation of synaptic potentials. The possible significance of the multiple neuroeffector connections of giant neurons is discussed.Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 90, No. 2, pp. 169–180, February, 2004.     

广州大学城广州管圆线虫疫源地调查

目的捕捉广州大学城褐云玛瑙螺(Achatina fulica)检查广州管圆线虫(Angiostrongylus cantonensis)第Ⅲ期幼虫的感染情况。方法采集大学城10所高校生活区和教学区褐云玛瑙螺,人工消化酶消化分离第Ⅲ期幼虫,计算感染率和感染度并与广州其他地区进行比较。结果除广东外语外贸大学、华南理工大学2个校园内未捕捉到褐云玛瑙螺外,其他8所高校均发现有褐云玛瑙螺;广州大学城广州管圆线虫总体感染率为11.8%(76/642),平均感染度为872条/螺,阳性螺中最高15725条,最低17条;中山大学校园内感染率和感染度比其他校园高,分别为22.0%(56/255),1007条/螺。结论广州大学城广州管圆线虫感染率低于广州其他地区。     

Expansion of Achatina fulica in Brazil and potential increased risk for angiostrongyliasis

The explosive introduction of the snail Achatina fulica in Brazil illustrates the current concern with global changes favouring dissemination of infectious diseases. The mollusc is an important host for Angiostrongylus cantonensis, which occurs in Asia and the Pacific Islands and is a causative agent for eosinophilic meningoencephalitis. In the Americas there is another metastrongylid worm, An. costaricensis, that causes abdominal disease and may also be transmitted by Ac. fulica. Although both infections may occur in focal outbreaks and with low morbidity, very severe complicated clinical courses pose a challenge for diagnosis and treatment. Data on abdominal angiostrongyliasis are briefly reviewed.     

Pharmacological activities of a new glycosaminoglycan,acharan sulfate isolated from the giant African snail Achatina fulica

Acharan sulfate (AS) is a glycosaminoglycan (GAG) prepared from the giant African snail, Achatina fulica. In this study, some biological activities of AS were evaluated on the basis of structural similarities to heparin/heparan sulfate and the biological functions of GAGs. We demonstrated that it exhibited strong immunostimulating activities as measured by carbon clearance test in mice and in vivo phagocytosis. It also exhibited a significant hypoglycemic activity in epinephrine (EP)-induced hyperglycemia as well as antifatigue effects by weight-loaded forced swimming test. And it showed hypolipidemic activities in cholesterol-rich mixture induced hyperlipidemia in rats. The above results indicate that AS has diverse biological activities and suggest therapeutically important target molecules.     

海南省广州管圆线虫中间宿主感染现状调查

目的 了解海南省广州管圆线虫中间宿主感染现状,为继续开展防治工作提供科学依据.方法 2018-2019年,按海南省的地理方位和水系分布,抽取与2006年一致的5个调查点,采集广州管圆线虫中间宿主螺蛳,以"肺检法"结合"匀浆法"检测中间宿主并查找广州管圆线虫幼虫.结果 2018-2019年,在5个调查点共检测野外采集螺蛳...     

广州市番禺地区褐云玛瑙螺和福寿螺广州管圆线虫感染情况调查

目的了解广州市番禺地区褐云玛瑙螺和福寿螺广州管圆线虫感染情况。方法用人工胃液消化法对采集到的褐云玛瑙螺和福寿螺进行处理,镜下观察和计数广州管圆线虫第3期幼虫,比较不同地区、不同螺种的感染率和感染度;将螺体内检获的幼虫感染健康SD大鼠并解剖,以验证之前的检查结果。结果共检测褐云玛瑙螺367只,福寿螺357只,其中褐云玛瑙螺广州管圆线虫感染率为22.62%,阳性螺感染度为57.00条/螺;福寿螺感染率为3.08%,阳性螺感染度为1.64条/螺。大岗、石碁、化龙、榄核4镇和南沙区褐云玛瑙螺广州管圆线虫感染率分别为13.33%、15.00%、20.93%、73.68%和8.41%,福寿螺感染率分别为5.88%、2.88%、1.89%、0%和3.96%。结论番禺地区褐云玛瑙螺和福寿螺均存在广州管圆线虫感染,且以褐云玛瑙螺感染较为严重。不同调查区域间螺的感染情况亦存在一定差异。