Subconjunctival Loa loa worm: first case report in Brazil / Verme subconjuntival da espécie Loa loa: primeiro caso no Brasil

We report the first case of ocular infestation by Loa loa in Brazil. Loiasis is caused by infestation with Loa loa, a filarial parasite originally found in the rainforests of western and central Africa. It is transmitted by the bite of the fly Chrysops and has been recently described in other places other than Africa, in African immigrants or travellers. Our case is a 33 year-old woman from Cameroon who was living in São Paulo, Brazil, for 5 years. She was asymptomatic until one morning she started feeling "something moving" in the left eye. Under topical anesthesia, on the slit lamp, a moving worm was removed from the subconjunctival space, which later was confirmed to be a male Loa loa adult specimen. Blood tests revealed microfilaraemia of 129 mf/mL. The patient was treated with 400 mg oral albendazole for 3 weeks and 60 mg prednisone. This report illustrates an unusual ocular disease, which is extremely rare outside of Africa, but easily diagnosed and treated. Ophthalmologists should be aware of it, in face of an increasingly globalized world.

Este é o primeiro relato na literatura nacional e internacional de infestação ocular por Loa loa no Brasil. A loíase é uma filariose causada pelo parasita Loa loa, encontrado nas florestas tropicais da África equatorial. A transmissão se dá pela picada do mosquito Chrysops e casos têm sido descritos em países não africanos, em imigrantes e viajantes. O presente caso trata-se de uma paciente de 33 anos natural de Camarões e residente em São Paulo, Brasil, há 5 anos. Até então assintomática, uma manhã sentiu algo "se mexendo" em seu olho esquerdo. Sob anestesia tópica, na lâmpada de fenda, um verme altamente móvel foi removido do espaço subconjuntival e enviado para identificação, que confirmou tratar-se de um espécime macho adulto de Loa loa. Testes sanguíneos revelaram microfilaremia de 129 mf/mL. A paciente foi tratada com albendazol 400 mg e prednisona 60 mg esquema regressivo por 3 semanas. Este relato ilustra uma doença excepcionalmente rara no Brasil, e praticamente desconhecida dos oftalmologistas em nosso país.

Subconjuctival Loa loa with Calabar Swelling

Loa loa is unique among the human filariae in that adult worms are occasionally visible during subconjuntival migration. A 29-yr-old African female student, living in Korea for the past 5 yr without ever visiting her home country, presented with acute eyelid swelling and a sensation of motion on the left eyeball. Her symptoms started one day earlier and became worse over time. Examination revealed a threadlike worm beneath the left upper bulbar conjunctiva with mild eyelid swelling as well as painless swelling of the right forearm. Upon exposure to slit-lamp illumination, a sudden movement of the worm toward the fornix was noted. After surgical extraction, parasitologic analysis confirmed the worm to be a female adult Loa loa with the vulva at the extreme anterior end. On blood smear, the microfilariae had characteristic features of Loa loa, including sheath and body nuclei up to the tip of the tail. The patient also showed eosinophilia (37%) measuring 4,100/microliter. She took ivermectin (200 microgram/kg) as a single dose and suffered from a mild fever and chills for one day. This patient, to the best of our knowledge, is the first case of subconjunctival loiasis with Calabar swelling in Korea.

A case of loiasis

The prevalence of Loa loa infections in non-endemic areas such as Korea is very low, even though it is quite common in the endemic regions of West and Central Africa. We describe a patient who presented with temporary localized edema (classical Calabar swellings) after travelling to Cameroon and in whom the diagnosis of loiasis was made by ELISA. This is the second reported case of loiasis in Korea. As international travel is becoming more frequent, Loa loa infection should be considered in the differential diagnosis for patients with eosinophilia and Calabar swellings in Korea.