Purpose
Of all myiasis cases reported (infestations of living tissue by the eggs or larvae of flies) 5% are ophthalmomyiasis (infestations in and around the eye). The authors analyze the literature and demonstrate the ability to graphically map cases of ophthalmomyiasis utilizing Google Earth by using free online tools for Geographic Information Systems (GIS). Our primary outcome is the number of reports that have sufficiently detailed geospatial data to construct a meta-analysis and to represent those cases on an interactive map.
Methods
A PubMed search identified a list of ophthalmomyiasis cases which was exported as an XML file. A free software program, pubmed2xl, was used to convert this XML file to a Microsoft Excel file. Only 188 articles comprising 569 cases had adequate geographic information to geocode the location data to yield a latitude and longitude (using a GoogleMapping.xlsm), as required by Google Earth. Finally a KML file was constructed utilizing a free tool, XLS2KML.xls, which could be opened within Google Earth.
Results
Of 409 published reports of ophthalmomyiasis on PubMed, 188 articles (46%) had sufficient geographic data to permit mapping, comprising 569 cases. The specific site affected is described as conjunctiva in 191 cases (33%), eyelid in 10 (2%), cornea in 1 (less than 1%), orbit in 25 (4%), ophthalmomyiasis interna in 30 (5%), ophthalmomyiasis externa in 140 (25%), unspecified in 158 (28%) and multiple sites in 14 (2%). There are 53 countries that reported cases, with the top being from Libya with 121 cases (21%), Italy with 69 (12%), and India with 62 (11%). Interestingly, of 25 orbital cases, 16 cases (64%) are related to orbital carcinoma. When the final KML file, derived from free online tools, is opened in Google Earth, any user can successfully view complete PubMed information on an interactive and customizable map, allowing further analysis of the intersection of disease and geography.
Conclusions
Our demonstration shows that GIS integration may be useful for the analysis of ophthalmomyiasis and can provide a novel user interface at minimum cost. However, the current reporting of geospatial data requires further standardization.
Keywords: 459 clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology •
463 clinical (human) or epidemiologic studies: prevalence/incidence •
473 computational modeling