An outbreak of trematode-induced granulomas of the conjunctiva☆
Received 31 July 2000; accepted 6 March 2001.
Abstract
Purpose
To describe the epidemiologic, clinical, and histopathologic features of trematode granulomas of the conjunctiva, eyelid, and anterior chamber in pediatric patients.
Design
Prospective noncomparative case series.
Participants
Forty-one children from a southern Indian village with conjunctival granulomas.
Methods
The village of Sellananthal was selected for a field visit after analysis of earlier hospital-based allergic conjunctival granuloma cases. Children with ocular diseases were examined, and histories of exposure to assumed risk factors and clinical findings were evaluated. Selected patients were brought to the base hospital for excisional biopsy. Serial sections obtained from the excised nodules were examined for the presence of a parasite.
Main outcome measures
Histopathologic examination of excised conjunctival lesions or response of lesions to local medical therapy.
Results
In this year-long prospective study, 41 children (16 years or younger; 38 boys and 3 girls) with clinical features of allergic conjunctival granulomas were examined. Thirty-four patients were from a single village located in the southern Indian state of Tamil Nadu; the remaining 7 were from various parts of the same state. All children swam in their village’s freshwater pond. Twenty patients with nodules less than 5 mm in diameter received medical treatment; 13 with larger nodules underwent surgical excision of the lesions. Nine of these 13 cases revealed a zonal granulomatous inflammation admixed with eosinophilic leukocytes; 4 of these 9 displayed fragments of the tegument and internal structures of a trematode and Splendore-Hoeppli phenomenon. The remaining 4 of the 13 cases revealed nongranulomatous inflammation made up of lymphocytes, histiocytes, and eosinophils. Eight patients refused surgical treatment.
Conclusions
In southern India, one cause of allergic conjunctival granulomas in children seems to be trematode infection. The clustering of cases in a single village and exposure to a village freshwater pond indicate the need for an epidemiologic investigation and study of the parasite’s life cycle. Sporadic cases from other parts of the state with similar histories of exposure to their local pond or river water suggest a widespread distribution of the etiologic agent.
2Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, Washington, USA
3Doheny Eye Institute and the Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
Reprint requests to Narsing A. Rao, MD, Doheny Eye Institute, 1450 San Pablo Street, DVRC-211, Los Angeles, CA 90033
☆ Supported in part by core grant EY03040, National Eye Institute, Bethesda, Maryland.
ABSTRACT