Imported Loa loa filariasis: three cases and a review of cases reported in non-endemic countries in the past 25 years

Abstract

The aim of this study was to highlight the increasing chance of Western physicians encountering patients (both immigrants and expatriates/travelers) seeking help for loiasis. Methods: We describe three cases of imported loiasis observed at two hospitals in Italy and France, and present a review of all previously published cases in the medical literature in the last 25 years . The search was performed using PubMed and Scopus databases using the terms ''Loa loa'' AND ''loiasis''. Results: We reviewed 101 cases of imported loiasis of which 61 (60.4%) were reported from Europe and 31 (30.7%) from the USA. Seventy-five percent of infestations were acquired in three countries: Cameroon, Nigeria, and Gabon. Overall, peripheral blood microfilariae were detected in 61.4% of patients, eosinophilia in 82.1%, eye worm migration in 53.5%, and Calabar swellings in 41.6%. However, Calabar swellings and eosinophilia were more common among expatriates/travelers, whereas African immigrants were more likely to have microfilaremia. Eye worm migration was observed in a similar proportion in the two groups. Only 35 patients (including the three described here) underwent clinical follow-up for a median period of 10.5 months (range 1-84 months); clinical relapse occurred in three of these patients and persistence or reappearance of blood microfilaria in another two. Conclusions: Due to increasing travel and the migration of people from the endemic countries of West Africa to Europe and the USA, we speculate on the possible emergence of loiasis. Western physicians should be aware of the typical (eye worm migration and Calabar swellings) as well as unusual clinical presentations.

Aetiologies of creeping eruption: 78 cases

“…The patient with loiasis did not present with either the typical ‘eye worm migration’ or with Calabar oedema, but with a creeping eruption of the eyelid. She did not have positive microfilaraemia, in contrast with other imported cases . As previously described, the disease appeared decades after return .…”

“…As previously described, the disease appeared decades after return . Moreover, after treatment with diethylcarbamazine, the patient presented a paradoxical adverse reaction …”

Eosinophilia in Infectious Diseases

“…However, microfilariae are not often detected in the blood in these patients [87, 88]. The minimum latency period appears to be 4-6 months [88], but it may take years [89] following infection for symptoms to develop. In the visitor and expatriate, Calabar swellings (migratory angioedema) on the limbs and/or face are the most common symptoms.…”

“…Other symptoms commonly seen are pruritus and urticaria [88]. Eosinophilia is essentially universal in non-endemic patients, typically marked (average is 3,000-4,000/μL) [86, 87, 89] and may mediate some of the pathologic findings in this infection.…”

Chronic symptomatic and microfilaremic loiasis in a returned traveller

“…Migration of adults across the eye manifests as a foreign body sensation; a worm moving across the conjunctiva may be noted in about 50% of cases. 3 Clinical features differ between patients who live in endemic regions and those who were born outside but travel to endemic regions. 4 Our patient's case is notable because, although symptomatic disease is more common among shortterm travellers, the presence of microfilaremia is more consistently seen in patients from endemic areas who often show no symptoms.…”