Intraocular Parasitic Infections

Parasitic Eye Diseases: Nuances in Rapid Identification and Advanced Microscopy

AIM

To study parasitic eye diseases in a tertiary institute of North-east India by live examination of parasites, rapid staining, and scanning electron microscopy (SEM).

METHODS

A 12-year retrospective analysis was performed and all patients diagnosed with ocular parasitic diseases were identified. Examination under a compound microscope, fluorescein staining, and scanning electron microscopy were done.

RESULTS

A total of 160 ocular parasitosis cases were identified.     The cases for which rapid staining and SEM studies were done included Cysticercosis (n = 18, 11.25%), Hydatidosis (n = 5, 3.13%), Dirofilariasis (n = 5, 3.13%), Thelaziasis (n = 3, 1.87%), and Gnathostomiasis (n = 2, 1.25%). Live examination was performed in 11 cases (6.63%) and 8 cases (4.82%) underwent scanning electron microscopy. .

CONCLUSION

Fluorescein staining for identification of parasites and SEM study helped in detailing microscopic and ultrastructural findings.

Case report: an unusual unilateral pterygium - a secondary pterygium caused by parasitosis in the scleral fistula

BACKGROUND

Ocular parasitosis can cause eye damage, which contribute to eye symptoms such as burning, itching and even blindness. It is uncommon to see the parasitosis lying in the sclera layer, neither it causing pterygium. Here, we present an unusual case of a secondary pterygium caused by intrascleral worm.

CASE PRESENTATION

A 52-year-old women complained about discomfort in right eye for 6 years. Slit-lamp examination indicated a thickened triangular layers of conjunctiva extending from the nasal edge to the cornea. The diagnosis was pterygium in the right eye. To our surprise, after scleral of nasal side exposed, we could see a tiny fistula right in the sclera which lied right under the pterygium, with an alive and motile worm inside. An intrascleral fistula was noted. Then the worm was removed by forceps from the fistula, which was creamy white, thread-like and 1 cm long.

DISCUSSION AND CONCLUSIONS

As far as we known, it is the first case of an intrascleral worm hidden beneath the conjunctiva which caused the secondary pterygium. It is hard to know the etiology of the secondary pterygium which caused by parasitosis in the scleral fistula untill excision surgery. It is hard to imagine the worm was living in the sclera of the patient for a long-time.

Aqueous humor cytokines and cellular profiles in pediatric ocular granulomas caused by theTrematode Fluke Procerovum sp

Background: Children from coastal areas of South India develop granulomatous eye disease after swimming in their village ponds, the causative organism being trematode Procerovum.Aim: To understand the pathogenesis by analyzing the cellular profile, cytokines, and chemokines of aqueous fluid.Methods: This was a prospective study over 1 year on pediatric patients with ocular granuloma caused by a Trematode Fluke Procerovum sp. Granuloma was aspirated along with 100 µl volume of aqueous humor. Immunohistochemical analysis of granuloma was performed. Bio-Plex Pro™ Human Cytokine 17-plex Assay (M5000031YV) was used to measure cytokine and chemokines.Results: The immunohistochemistry revealed predominantly eosinophils, followed by macrophages (CD68+) and T - lymphocytes (CD4+). Both T-helper (Th) 1 and 2 mediated cytokines and chemokine levels were significantly high. As the disease duration increased, direct Th1 response reduced and was replaced by IL-12 and IL-17 mediated secondary Th1 response.Conclusion: Procerovum associated granulomatous disease is immunologically characterized by Th1 and Th2 cell-mediated responses. A balance between both arms maintains the eyes between granulomatous inflammation and healing by fibrosis.

Irreversible Ocular Lesions in a Dog With Angiostrongylus Vasorum Infection

This report describes a 10-month-old dog with a sudden loss of vision and severe dyspnoea. The ocular examination revealed bilateral panuveitis, lens subluxation, secondary glaucoma, and retinal detachment. In addition, the ocular ultrasound showed in the vitreous body of the right eye, a small doubled-lined foreign body compatible with an intraocular parasite. Radiographs of the thorax revealed an increased opacity with mixed lung pattern (alveolar and bronchial) and thoracic ultrasonography showed several subpleural nodules. The presence of Angiostrongylus vasorum first stage larvae was confirmed with 324 larvae per gram of feces and an antigen test for the parasite (AngioDetect, IDEXX) also yielded a positive result. The severe and irreversible ocular lesions described in this case enhanced the complexity of the clinical picture of canine angiostrongylosis. Infection with the parasite should be included in the list of differential diagnoses for ocular uveitis to avoid potentially serious complications related to a missed or delayed diagnosis.

Update on pathology of ocular parasitic disease

Parasites are a group of eukaryotic organisms that may be free-living or form a symbiotic or parasitic relationship with the hosts. Consisting of over 800,000 recognized species, parasites may be unicellular (Protozoa) or multicellular (helminths and arthropods). The association of parasites with human population started long before the emergence of civilization. Parasitic zoonotic diseases are prevalent worldwide including India. Appropriate epidemiological data are lacking on existing zoonotic parasitic diseases, and newer diseases are emerging in our scenario. Systemic diseases such as cysticercosis, paragonimiasis, hydatidosis, and toxoplasmosis are fairly common. Acquired Toxoplasma infections are rising in immune-deficient individuals. Amongst the ocular parasitic diseases, various protozoas such as Cystoidea, trematodes, tissue flagellates, sporozoas etc. affect humans in general and eyes in particular, in different parts of the world. These zoonoses seem to be a real health related problem globally. Recent intensification of research throughout the world has led to specialization in biological fields, creating a conducive situation for researchers interested in this subject. The basics of parasitology lie in morphology, pathology, and with recent updates in molecular parasitology, the scope has extended further. The current review is to address the recent update in ophthalmic parasites with special reference to pathology and give a glimpse of further research in this field.

Ocular Gnathostomiasis in Brazil: A Case Report

Gnathostomiasis is a parasitic disease caused by nematode larvae ingestion of 15 known species of the genus Gnathostoma (one of the Gnathostomatidae family members). This parasite uses freshwater fish as a host and can infect - through the consumption of raw fish or their viscera - other animals such as dogs, cats, chickens, pigs, and humans. This parasitic disease, with humans acting as hosts, has been known since 1945 (India), and ocular complications have been known since 2004 (intravitreal; also described in India). Latin American countries, especially Mexico and Peru, have reported cases of the disease since 1970. The first dermatological case was reported in Brazil in 2009 (the individual had acquired the disease in Peru). This article describes the first reported ophthalmic case of the disease in Brazil and refers to a male patient, 30 years old, living in the municipality of Juruá, Amazonas State. The disease evolved within 30 days through a fistulized tumor in the inner corner of the lower eyelid. Following excision, the anatomical and histopathological examination revealed the presence of a different parasite species from other previously known genera.

Imported intraocular gnathostomiasis with subretinal tracks confirmed by western blot assay

We report a case of intraocular gnathostomiasis diagnosed by western blot assay in a patient with subretinal tracks. A 15-year-old male patient complained of blurred vision in the right eye, lasting for 2 weeks. Eight months earlier, he had traveled to Vietnam for 1 week and ate raw wild boar meat and lobster. His best-corrected visual acuity was 20/20 in both eyes and anterior chamber examination revealed no abnormalities. Fundus examination showed subretinal tracks in the right eye. Fluorescein angiography and indocyanine green angiography showed linear hyperfluorescence of the subretinal lesion observed on fundus in the right eye. Ultrasound examination revealed no abnormalities. Blood tests indicated mild eosinophilia (7.5%), and there was no abnormality found by systemic examinations. Two years later, the patient visited our department again for ophthalmologic evaluation. Visual acuity remained 20/20 in both eyes and the subretinal tracks in the right eye had not changed since the previous examination. Serologic examination was performed to provide a more accurate diagnosis, and the patient's serum reacted strongly to the Gnathostoma nipponicum antigen by western blot assay, which led to a diagnosis of intraocular gnathostomiasis. This is the first reported case of intraocular gnathostomiasis with subretinal tracks confirmed serologically using western blot in Korea.