Intraocular Parasitic Infections

A parasite is a living organism that receives some of its basic nutritional requirements through intimate contact with another living organism. When the parasite reaches the eye, ocular complications occur due to mechanical, immunologic, or allergic reactions. When an ophthalmologist detects a parasite in the eye, it is often difficult to identify the exact organism. Lack of methodological uniformity in management of ocular parasitosis emphasizes the need for standardization, including construction of a management algorithm. Knowledge on immunoreactivity in systemic parasitology has grown remarkably, but translational research from bench to bedside needs to be improved. Newer molecular diagnostic techniques are essential for ophthalmic application. Many parasitic worms are developing resistance to available drugs, necessitating discovery of the next generation of anti-parasitic agents. The aim of this review is to understand the existing literature on ocular parasitosis, to highlight diagnostic and therapeutic advances, and to analyze the management algorithm on ocular parasitosis.     

Bilateral Ocular Myiasis Interna Caused by Botfly (Oestrus ovis): A Case Report

The sheep nasal botfly Oestrus ovis is the commonest of several species of dipteran fly whose larvae are obligatory parasites in the nasal cavities and frontal sinuses of sheep but may cause infestation (myiasis) in man, commonly as external infestations and rarely, involves inner coat of the eye (Ocular myiasis interna). We report an imported case of Bilateral Ocular myiasis interna in an Indian boy.     

食用醋或酱油对旋毛虫肌幼虫感染性和生殖力的影响

目的观察食用醋或酱油对旋毛虫肌幼虫感染性和生殖力的影响。方法140只雄性昆明小鼠随机均分为14组,分别喂饲经食用醋(总酸浓度4.5%,pH3.05)、食用酱油(含19.3%NaCl)和生理盐水浸泡不同时间的含有300条旋毛虫肌幼虫的小鼠肌肉(重约0.02g),于喂饲后第7天和第42天每组各剖杀5只小鼠,分别观察肠道成虫、肌幼虫的数量和生殖力指数(RCI)。结果小鼠喂饲经食用醋处理3、6、12和24h的旋毛虫肌幼虫后,其肠道成虫数分别为77、41、0和0条,RCI分别为52.48、18.45、0和0,均显著低于生理盐水对照组肠道成虫数(分别为121、121、116和101条)和RCI(分别为159.10、124.56、73.63和42.17)(P0.05)。小鼠喂饲经食用酱油处理12、24、36和48h的旋毛虫肌幼虫后,肠道成虫数(分别为79、39、3和0条)和RCI(分别为48.75、20.80、1.87和0)亦均明显低于对照组(116、101、95和89条,73.63、42.17、21.53和4.13)(P0.05)。感染小鼠的肠道成虫数和RCI均随醋或酱油处理时间的延长而降低(P0.05)。结论含旋毛虫肌幼虫的肌肉经食用醋或酱油处理后,肌幼虫的感染力和生殖力均明显下降。     

Posterior Internal Ophthalmomyiasis: Identification of a Surgically Removed Cuterebra Larva by Scanning Electron Microscopy

The clinical presentation of an 11-year-old boy with unilateral posterior internal ophthalmomyiasis is described. Ophthalmoscopy of the affected eye in this individual disclosed characteristic subretinal depigmented linear tracks and a larva within the vitreous. The intravitreal larva was retrieved successfully by pars plana vitrectomy and identified as the first instar of Cuterebra sp. (rodent botfly) by scanning electron microscopy. This was done by examining the external features of the larva by scanning electron microscopy and comparing them to scanning electron micrographs that were prepared on other first instar larvae of flies known to be implicated in internal ophthalmomyiasis. The study demonstrates the usefulness of scanning electron microscopy for taxonomic identification of fly larvae. Since even a small fragment of these organisms may contain characteristic features of external morphology, scanning electron microscopy may be useful in cases where the specimen is damaged or incomplete.     

Orofacial myiasis of the gingiva and nasal cavity: a report of two cases and general review

Background: Infestation of the orofacial region with live maggots is a distressing condition and many clinicians are not aware of the existence of such an entity. Usually the condition affects individuals who are debilitated, mentally challenged, and physically not able to attend to their personal needs because of lack of psychomotor coordination. Methods: This article describes two cases of orofacial myiasis reported at a rural dental school in India. Removal of the live maggots, supportive treatment, management of the cases, and morphologic features of maggots are described. Results: Both the patients belonged to a low socioeconomic group and were physically and mentally challenged. Maggot removal improved the patients’ pain and distress, and entomologic study identified the maggots as belonging to Chrysomya bezziana. Conclusions: Oral myiasis is more prevalent than commonly believed to be and an astute practitioner should be aware of such maggots in the mouth, in cases of oral and maxillofacial trauma and in vulnerable categories of patients. These patients are not physically or mentally endowed to ward off flies or complain about worms burrowing their way into oral wounds. Occurrences of such cases are rare in developed countries and reflect the lack of special care for the vulnerable group of patients belonging to certain geographic areas.     

旋毛虫成囊前期幼虫排泄分泌抗原的研究进展

在旋毛虫感染过程中,成囊前期幼虫（PEL）是旋毛虫侵入宿主肌肉的侵入期。旋毛虫PEL比成囊期幼虫（EL）在宿主体内约早2周出现。成囊前期幼虫抗原（PELA）对旋毛虫病的早期免疫学诊断具有较高的敏感性。而旋毛虫排泄分泌抗原具双重免疫功能,即有良好的抗原性和免疫原性。因此,本文就旋毛虫成囊前期幼虫ES抗原研究进展做一综述。     

HCV CE2融合蛋白在家蚕培养细胞、蚕幼虫中的表达及其初步应用

目的:高效表达HCV CE2融合蛋白并进行初步应用. 方法:将2a型HCV全长CE2基因的cDNA重组于质粒pBacPAK8,构建重组转移载体pBacPAK-CE2,与经线性化修饰的家蚕核型多角体病毒(BmNPV)DNA共转染家蚕培养细胞株,构建重组病毒. 双酶切及PCR鉴定重组病毒基因组中目的片段的表达. 重组病毒感染BmN细胞株及五龄家蚕幼虫后,SDS-PAGE分析细胞培养上清、细胞抽提物及幼虫体液样品中,HCV CE2融合蛋白的特异性条带. 并用间接ELISA法初步检测表达产物的生物活性. 结果:双酶切及PCR鉴定重组病毒基因组含有约1.6 kb的目的片段,重组病毒感染后的BmN细胞培养上清、细胞抽提物及幼虫体液样品中,均可见一Mr约90×103的特异性条带;用间接ELISA检测证明表达产物具有较好的免疫原性. 结论:HCV CE2融合基因在家蚕培养细胞及蚕幼虫中获得了高效表达,并具有生物活性,为进一步进行疫苗的研究及临床诊断试剂的开发奠定基础.     

A rare case of cutaneous larva migrans due to Gnathostoma sp

A 28-year-old lady presented with recurrent erythematous skin lesions in different parts of the body for 3 months. There were several episodes of worm coming out of the lesions. Examination of the worms in the parasitology laboratory revealed it to be a larva of Gnathostoma sp. She was advised treatment with Albendazole for 21 days, and there was no recurrence of lesions.