Zoonotic helminths affecting the human eye

Abstract

Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE) may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis), food consumption (sparganosis, trichinellosis) and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis). Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs) or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber) causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment.Homines amplius oculis, quam auribus creduntSeneca Ep 6,5Men believe their eyes more than their ears

Parasites of edible land snails in Edo State, Nigeria

“…Further investigation on this is however required to clearly defi ne the role of these snails within the context of parasite development and disease transmission. In any case, human infection has been reported after the consumption of Alaria-infected host (Otranto and Eberhard, 2011 (Soliman, 2008). In this study, A. fulica harboured the widest range of parasites among the snail species collected; two of which are F. gigantica and S. mansoni.…”

Subconjunctival infestation with Setaria

“…Sporadic cases have been reported in Northern Europe and Poland (Melsom et al, 2011;Wesolowska et al, 2010). The nematode ophthalmic involvement in humans may be periorbital, subconjunctival or intraocular (Otranto et al, 2011). Most cases of subconjunctival infestations with nematodes described in the literature belong to the genus Dirofilaria (Melsom et al, 2011;Wesolowska et al, 2010;Khoramnia & Wegner, 2010).…”

“…Human ocular infestations with nematodes are rarely seen in Central and Eastern Europe, as they usually require higher outdoor temperatures for the development (Otranto et al, 2011). Sporadic cases have been reported in Northern Europe and Poland (Melsom et al, 2011;Wesolowska et al, 2010).…”

Thelazia Callipaeda and Eye Infections

“…Global warming and migration of vector -transient hosts of these parasites, completely changed the epizootic and epidemiological characteristics of vector-born zoonosis (1). Helminthic infections of the eye may result from a specific helminths tropism, such as the case with tropical species filaria Onchocerca volvulus, which infects about 17.7 million people, and is caused by infection of microfilariae which are migrating from the subcutaneous tissue to the eye and can cause iritis, keratitis, chorioretinitis, optic nerve atrophy (2). Loa loa, the tropical filaria too may also damage the eye.…”

“…Many ophthalmologists and general practitioners do not consider the possibility of this infection. Even if they diagnosed thelaziosis they did not publish those data, and it is very difficult to estimate the prevalence and incidence of this parasitic infections of the eye, because the data in the reference literature are scarce and mostly limited to individual case reports from various countries (2).…”