Interna Caused
Human myiasis caused by bot fl ies of nonhuman animals is rare but may be increasing. The treatment of choice is laser photocoagulation or vitrectomy with larva removal and intraocular steroids. Ophthalmomyiasis caused by Hypoderma spp. should be recognized as a potentially reversible cause of visio...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.306.4416 http://wwwnc.cdc.gov/eid/article/14/1/pdfs/07-0163.pdf |
| Summary: | Human myiasis caused by bot fl ies of nonhuman animals is rare but may be increasing. The treatment of choice is laser photocoagulation or vitrectomy with larva removal and intraocular steroids. Ophthalmomyiasis caused by Hypoderma spp. should be recognized as a potentially reversible cause of vision loss. Ophthalmomyiasis interna is invasion of the globe by larvae of any species of oestrid flies; ophthalmomyiasis externa involves only the external ocular structures (1). Dermatobia hominis, endemic to tropical or subtropical areas, and Oestrus ovis (sheep bot fly) cause most cases of ophthalmomyiasis (2). Both typically cause ophthalmomyiasis externa (2). Only 2 bot flies inhabit Nearctic circumpolar regions: the Caribou bot fly (Hypoderma tarandi) and the Caribou nasal bot fly (Cephenemyia trompe), a nonhuman pathogen (2). H. tarandi is a nonbiting fly whose obligate endoparasitic larvae typically affect caribou throughout their circumpolar range (2,3). From late June to early September. the fly lays eggs directly on the guard hairs of the caribou (2,3). Once deposited, eggs hatch into larvae that penetrate skin (3). They move subcutaneously to reach the animal’s dorsal region, where they cut breathing holes and are encased within granulomatous cysts, termed warbles. There they develop for 9–11 months; in May or June of the following year, they leave the animal and pupate on the ground (3). Mated adult females are capable of long flights (≈900 km) in search of suitable hosts (3). Infestations by H. tarandi in humans are rare but are likely underreported (4). Related species, H. bovis and H. lineatum, inhabit various regions of North America, Europe, and Asia and have also been implicated in human disease (2,5). A third species that affects cattle and yaks in China (H. sinense) is also responsible for human infestations (2). The pathophysiology of human ophthalmomyiasis |
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