Sir,We report the case of a 24-year-old man, born in the coastal area of Gabon, who had migrated to France and presented to our department with the sensation of something wiggling over the right eyeball. He gave history of transient painful itchy red swellings on wrists, headache with redness in the eyes, and edema of the periorbicular soft tissues in the past 3 years. When first seen, an opaque wriggled motile thin and undulated worm was directly observed in the superotemporal subconjunctival space. The parasite was successfully extracted with toothed forceps [Figure 1]. Its morphological features were most consistent with the Loa loa species. Peripheral blood smear drawn around noontime was positive with microfilarial load at 3500 ml–1. To first decrease this high microfilarial load, the patient was treated with 2 weekly doses of ivermectin 200 μg/kg associated with 0.5 mg/kg/day corticosteroids and antihistaminic for 10 days. Three months later, although the patient became fully asymptomatic, the microfilarial load was still positive at 600 ml–1. He did not return for definitive cure with diethylcarbamazine.
Figure 1
Extraction of one adult Loa loa worm after conjunctival incision (snapshot from video)
Extraction of one adult Loa loa worm after conjunctival incision (snapshot from video)Loa loa worm is a human subcutaneous filarial nematode transmitted by a day-biting forest-dwelling fly of the genus Chrysops. Adult Loa loa worms migrate actively throughout the subcutaneous and collective body tissues. They are most conspicuous and irritating when passing beneath the conjunctiva of the eye. Calabar swellings are localized, tense, inflammatory pruritic subcutaneous edema seen in joints of extremities, lasting for 1–3 days. They represent areas of angioedema resulting from a host response to allergens released by the maturating worm and its metabolic products.[1] Definitive diagnosis is made either by identification of the adult worm in the subcutaneous tissue, the subconjunctiva, or sclera of the eye or by finding microfilariae in the blood from samples drawn around noontime. Microfilariae have diurnal periodicity and are found circulating in the peripheral blood during the day while staying in the vascular parts of the lungs at night. Nowadays, loiasis treatment remains difficult and not definitely codified. On this behalf, the regimen option definitely needs to be directly linked to microfilaremia level to ensure drug tolerance beyond the objective of complete eradication of the worm. The originality of our case is based on this emerging concept. Although treatment options depend on clinical presentation and occurrence of high (2000–8000 ml–1) or very high (>8000 ml–1) microfilaremia,[1] surgical removal of an adult worm from subconjunctiva is a minor curative procedure. Ivermectin has become the most antiparasitic agent used worldwide but can lead to residual microfilarial load when given in the management of loiasis.[2] High microfilarial loads should be decreased by a course of ivermectin, a prolonged administration of albendazole, or cytapheresis sessions to prevent occurrence of serious adverse events, including fatal encephalopathy induced by dying microfilariae.[3] Cytapheresis is helpful in decreasing very high microfilarial loads up to 75%.[4] Diethylcarbamazine kills both microfilariae and adult worms but has more side effects. Ivermectin and diethylcarbamazine should be given with steroid and antihistamine courses to decrease the risk of severe side reactions.
Figure 1