RESUMEN
Risk models derived from environmental data have been widely shown to be effective in delineating geographical areas of risk because they are intuitively easy to understand. We present a new method based on distances, which allows the modelling of continuous and non-continuous random variables through distance-based spatial generalised linear mixed models. The parameters are estimated using Markov chain Monte Carlo maximum likelihood, which is a feasible and a useful technique. The proposed method depends on a detrending step built from continuous or categorical explanatory variables, or a mixture among them, by using an appropriate Euclidean distance. The method is illustrated through the analysis of the variation in the prevalence of Loa loa among a sample of village residents in Cameroon, where the explanatory variables included elevation, together with maximum normalised-difference vegetation index and the standard deviation of normalised-difference vegetation index calculated from repeated satellite scans over time.
Asunto(s)
Modelos Lineales , Animales , Camerún/epidemiología , Humanos , Funciones de Verosimilitud , Loa , Loiasis/epidemiología , Loiasis/parasitología , Cadenas de Markov , Método de Montecarlo , Prevalencia , RiesgoRESUMEN
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.
Asunto(s)
Enfermedades de la Conjuntiva/parasitología , Infecciones Parasitarias del Ojo/parasitología , Loa/aislamiento & purificación , Loiasis/parasitología , Adulto , Animales , Brasil , Enfermedades de la Conjuntiva/diagnóstico , Infecciones Parasitarias del Ojo/diagnóstico , Femenino , Humanos , Loiasis/diagnósticoRESUMEN
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.