Ocular Filariasis in US Residents, Returning Travelers, and Expatriates

Several factors acting in concert now place US residents, returning travelers, and expatriates at risks of contracting ocular filariasis including increasing seroprevalence rates of zoonotic filariasis, international travel bringing tourists to and expatriates from filariasis-endemic regions, and warming temperatures extending distribution ranges of arthropod vectors. To describe the epidemiology and outcomes of ocular filariasis and to recommend strategies for the diagnosis, management, and prevention of ocular filariasis, internet search engines were queried with the key words in order to examine case reports and series of ocular filariasis in the US and elsewhere. Descriptive epidemiological, morphological, and molecular evidence now support increasing cases of ocular filariasis in domestic and wild animals and humans, with most cases caused by filarial worms including Dirofilaria repens and other zoonotic Dirofilaria species and Onchocerca lupi and other zoonotic Onchocerca species. Clinicians should maintain early suspicion of ocular filariasis in US residents, returning travelers, and expatriates who complain of combinations of red eye, eye pain, foreign body sensation, reduced visual acuity, and migrating ocular worms, even without significant peripheral eosinophilia or microfilaremia. Microfilariae of Wuchereria bancrofti, Brugia malayi, and O. volvulus may traverse the eye, but can usually be treated medically. Mobile adult worms trapped in the subconjunctiva or anterior chamber should be removed by ophthalmologists to permit species identification, prevent posterior uveitis and iritis, and stop worm migration into the posterior chamber which could require lens removal and vitrectomy for worm extraction causing further eye damage.