Case Report: A Human Case of Onchocerca lupi Mimicking Nodular Scleritis.

We report a case of human ocular onchocerciasis by zoonotic Onchocerca lupi presenting as nodular scleritis. Molecular analyses were used to confirm diagnosis at species level. In addition to few existing reports of human infection by O. lupi in Turkey, this case further suggests that the pathogen might be more common than previously reported, thus requiring further attention and investigations.

First report of Onchocerca lupi from Israel and confirmation of two genotypes circulating among canine, feline and human hosts.

Onchocerca lupi is a parasitic filarioid and the causative agent of canine ocular onchocercosis, a zoonotic disease of domestic dogs with sporadic reports in humans. A 13-year-old dog with no travel history outside of Israel was presented to an ophthalmology veterinary clinic in Israel with severe right ocular and periocular disease. After surgical exploration, thin helminths were removed from the dorsal sclera of the eye and identified as Onchocerca lupi by polymerase chain reaction according to the cytochrome c oxidase subunit I (cox1), reduced nicotinamide adenine dinucleotide dehydrogenase subunit 5 (nad5) and 12S rRNA genes. Phylogenetic trees and haplotype networks of the cox1 and nad5 genes confirmed the circulation of two genotypes: genotype 1 with worms from dogs, cats and humans from both the Old and New Worlds, and genotype 2 with specimens from Portugal and Spain. The Israeli sequences clustered in genotype 1 and were identical to O. lupi from the USA. Evidence of two genotypes separated geographically sheds light on the phylogeography and evolution of this zoonotic pathogen, and suggests a diverse pathology observed in different regions of the world.

Ocular zoonotic onchocerca infection in a resident of Oregon.

A long, slender filarial nematode was removed from the left anterior chamber of a resident of Oregon after several days of pain and blurred vision. The worm was identified as an Onchocerca, but it could not be further identified. This worm is the third zoonotic Onchocerca removed from the anterior chamber and the second case reported from the United States. Cases of zoonotic onchocerciasis continue to garner attention, and those cases affecting the eye are of particular interest.

A rare case of ocular onchocerciasis in India.

Onchocerca volvulus is a spirurid nematode that mainly affects the rural poor of Sub-Saharan Africa, Yemen and parts of Central and South Africa. River blindness, caused by Onchocerca volvulus, is considered to be the second commonest infectious cause of blindness worldwide. We report a rare case of ocular onchocerciasis where a live adult worm was extracted from the eye of a patient from a nonendemic region. The worm was identified as Onchocerca volvulus based on morphological features. The patient was treated with Ivermectin (0.2 mg/kg). At six months follow-up she had complete remission of symptoms.

A case of canine ocular onchocercosis in Portugal.

Onchocercosis is a newly recognized disease in dogs that has been reported with higher frequency in Europe and in the United States. We report a case of a 3-year-old male mongrel stray dog from the Algarve region (South Portugal) who had a retrobulbar granuloma containing a filaroid nematode of the genus Onchocerca. A gravid adult female parasite was embedded in a granulomatous inflammation adjacent to the sclera beyond the retina. The parasite was 191 to 267 mum in diameter (mean = 225 mum), surrounded by a cuticule and owing a uterus that was filled with small unsheated microfilariae. The cuticule consisted of two separated layers in longitudinal sections. The external layer had cuticular ridges and the internal layer contained striations. Sequencing of the COI and ND5 mitochondrial genes confirmed the identity of this parasite as Onchocerca lupi. Furthermore, the first sequence of the 12S mitochondrial gene is reported in this study.

Zoonotic intravitreal Onchocerca in Hungary.

OBJECTIVE: To report the case of a 65-year-old male patient from western Hungary who presented with rapidly progressive peripheral visual field (VF) loss and the sensation of an actively moving object in his central VF. DESIGN: Interventional case report. METHOD/INTERVENTION: A live nematode was removed from the anterior vitreous cavity by pars plana vitrectomy. RESULTS: The worm was successfully removed surgically, and the patient had an uneventful recovery. The nematode was identified as an immature filaria, most likely a member of the genus Onchocerca. CONCLUSIONS: Only 3 previous reports exist of human infection of the eye caused by zoonotic Onchocerca, 2 involving the subconjunctiva and 1 the cornea. Although rare, zoonotic onchocercal infection of the eye must be considered a differential diagnostic entity even in temperate climates.

Canine onchocercosis in Greece: report of further 20 cases and molecular characterization of the parasite and its Wolbachia endosymbiont.

Recently, sporadic cases of subconjunctival Onchocerca infection have been reported in dogs in Greece and Hungary. Herein we report further cases from Greece and the results of the molecular analysis of Onchocerca sp. removed from Greek dogs and its Wolbachia endosymbionts. Twenty dogs of various breeds, 1-11 years of age with subconjunctival onchocercosis (4 cases each in right or left eye, 12 cases in both eyes) were presented having similar manifestations. Periorbital swelling, exophthalmos, lacrimation, discharge, photophobia, conjunctival congestion, corneal edema, protrusion of the nictitating membrane, and subconjunctival granuloma or cyst formation were the most important clinical signs. After surgical excision of the periocular masses containing the worms, all animals recovered fully from onchocercosis. Based on the similarities of the clinical picture of the Greek and Hungarian cases, the similar morphology of the Greek and Hungarian isolates, and the identical sequences of the cytochrome oxidase gene of the filarial parasites and that of the 16S ribosomal RNA gene from their Wolbachia endosymbionts, the Onchocerca sp. isolated from dogs in Greece and Hungary appears to belong to the same species.

Ocular Onchocerca infections in two dogs in western United States.

Two dogs, one from California and one from Arizona, were found to have aberrant infections caused by filarial nematodes of the genus Onchocerca. In both cases, the parasites are localized in or near the eye. In one case the worm was located in the cornea and was surgically removed. In the second case, a very marked granulomatous reaction was induced in the retrobulbar space, mimicking an abscess. This eye was enucleated. The worms in both instances were female, and were gravid, i.e. contained microfilariae in utero, indicating that a male worm(s) had been present and mating had occurred. The exact identity of the species of Onchocerca responsible cannot be determined, although the features observed are most like Onchocerca lienalis of cattle. These cases represent the fourth and fifth such cases reported from the US, and are especially interesting because of the unusual location of the worms, the small number of recognized cases, and the similarity to a recent zoonotic human infection.

Zoonotic Onchocerca (Nematoda:Filarioidea) in the cornea of a Colorado resident.

OBJECTIVE: A female patient, resident in the state of Colorado, presented with iritis of the right eye. Slit-lamp examination showed the presence of a thin, threadlike worm entwined in the cornea. The patient was taken to surgery for removal of the parasite. DESIGN: A case report. INTERVENTION: A 3-mm-long supertemporal incision was made in the cornea and further dissected until the worm could be grasped and removed by gentle traction. RESULTS: The worm, a filarial nematode, was identified as a member of the genus Onchocerca, most likely Onchocerca cervicalis, a natural parasite of horses. The patient had an uneventful recovery, and 1 week after surgery, her visual acuity, intraocular pressure, and corneal edema were all resolving. CONCLUSION: In the United States and elsewhere, most cases of zoonotic filarial infection involving the eye are caused by Dirofilaria or Dipetalonema-like worms. However, the current case was caused by a species of Onchocerca. This is the first case of zoonotic Onchocerca from the eye to be reported, only the second case of zoonotic Onchocerca in the United States, and the seventh case worldwide. The worm was removed surgically, and the patient had an uneventful recovery.