RESUMEN
BACKGROUND: Tungiasis, an ectoparasitosis caused by the female sand flea Tunga penetrans, is an important health problem in many impoverished communities in the tropics. Sand flea disease is associated with a broad spectrum of clinical pathology and severe sequels are frequent. Treatment options are limited. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the effectiveness of the intermittent application of the plant-based repellent Zanzarin to reduce infestation intensity and tungiasis-associated morbidity in a resource-poor community in Brazil, characterized by a very high attack rate. The study population was randomized into three cohorts. Initially, during a period of four weeks, the repellent was applied twice daily to the feet of all cohort members. This reduced the number of embedded sandfleas to 0 in 98% of the participants. Thereafter members of cohort A applied the repellent every second week twice daily for one week, members of cohort B every fourth week for one week, and members of cohort C served as controls. Infestation intensity and tungiasis-associated morbidity were monitored during five months. The intermittent application of Zanzarin for one week every second week significantly reduced infestation intensity from a median 4 lesions (IQR 1-9) during the whole transmission season. In contrast, in cohort B (application of the repellent every fourth week) the infestation intensity remained twice as high (median 8 lesions, IQR 9-16; pâ=â0.0035), and in the control cohort C 3.5 times as high (median 14 lesions; IQR 7-26; pâ=â0.004 during the transmission season). Tungiasis-related acute pathology remained very low in cohort A (median severity score 2; IQR 1-4) as compared to cohort B (median severity score 5; IQR 3-7; p<0.001), and control cohort C (median severity score 6.5; IQR 4-8; p<0.001). CONCLUSIONS/SIGNIFICANCE: Our study shows that in a setting with intense transmission, tungiasis-associated morbidity can be minimized through the intermittent application of a plant-based repellent.
Asunto(s)
Control de Enfermedades Transmisibles , Repelentes de Insectos/administración & dosificación , Preparaciones de Plantas/administración & dosificación , Tunga/efectos de los fármacos , Tungiasis/prevención & control , Adolescente , Adulto , Aloe/química , Animales , Brasil/epidemiología , Niño , Preescolar , Cocos/química , Estudios de Cohortes , Infestaciones Ectoparasitarias/epidemiología , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Aceites de Plantas/administración & dosificación , Pobreza , Tungiasis/tratamiento farmacológico , Tungiasis/economía , Tungiasis/parasitología , Adulto JovenRESUMEN
Tungiasis, caused by the sand flea Tunga penetrans, is a health problem in many impoverished communities in Latin America, the Caribbean, and sub-Saharan Africa. Sand flea disease is associated with a broad spectrum of clinical and histological pathology. The factors determining the disease burden in endemic communities are not well understood, and severity of clinical pathology has never been assessed quantitatively. Thus, two severity scores were developed: one for acute disease and one for chronic sequels. These scores were evaluated in a cohort of 70 severely infested patients living in a shantytown in Fortaleza, a capital city in Northeast Brazil. Patients were examined during a period of 25 days and followed-up after a twice daily application of a plant-based repellent to prevent reinfestation. The severity score for acute disease symptoms significantly correlated with the infestation rate and the number of embedded fleas. It turned zero when reinfestation was prevented. The score for chronic disease also significantly correlated with the infestation rate. Tungiasis is associated with considerable acute and chronic morbidity. The degree of acute morbidity is directly related to the number of embedded sand fleas. When transmission is interrupted, the chronic morbidity reflects the infestation rates individuals have experienced in the past.
Asunto(s)
Infestaciones Ectoparasitarias/patología , Enfermedades del Pie/parasitología , Mordeduras y Picaduras de Insectos/patología , Siphonaptera/fisiología , Adolescente , Animales , Niño , Preescolar , Infestaciones Ectoparasitarias/prevención & control , Femenino , Pie/patología , Enfermedades del Pie/patología , Humanos , Repelentes de Insectos/uso terapéuticoRESUMEN
Tungiasis is a parasitic skin disease prevalent in impoverished populations in the tropics and associated with considerable morbidity. Treatment options are limited and prophylaxis has never been attempted. We assessed the effectiveness of a plant-based repellent to prevent infestation with Tunga penetrans and sand flea disease in an urban squatter settlement in Fortaleza, Northeast Brazil. Two cohorts were formed. One cohort started with the intervention while another served as control. The plant-based repellent Zanzarin was applied twice daily on the skin of the feet. After 4 weeks and a wash-out-phase of another 2 weeks, cross-over was performed. Study members were examined twice per week for the presence of newly embedded sand fleas. The number of viable and dead sand fleas and the total number of sand flea lesions were determined. Sentinel rats were used to assess local transmission dynamics. Outcome measures were the number of newly embedded sand fleas per individual per day, number of sand flea lesions per individual according to the stage, as well as type and degree of clinical pathology. Zanzarin applied twice daily on the feet reduced the number of newly embedded fleas by 92% (interquartile range 81-100%), the total number of lesions by 87% (81-98%) and reversed tungiasis-associated clinical pathology almost completely. In conclusion, in a setting in which tungiasis is an important health threat, the daily application of a plant-based repellent prevented the infestation with T. penetrans and sand flea disease.
Asunto(s)
Infestaciones Ectoparasitarias/prevención & control , Mordeduras y Picaduras de Insectos/prevención & control , Repelentes de Insectos/administración & dosificación , Ácido Pantoténico/análogos & derivados , Aceites de Plantas/administración & dosificación , Siphonaptera/crecimiento & desarrollo , Administración Tópica , Adolescente , Adulto , Anciano , Animales , Brasil , Niño , Preescolar , Estudios de Cohortes , Estudios Cruzados , Combinación de Medicamentos , Femenino , Enfermedades del Pie/parasitología , Enfermedades del Pie/prevención & control , Humanos , Lactante , Repelentes de Insectos/farmacología , Masculino , Persona de Mediana Edad , Ácido Pantoténico/administración & dosificación , Ácido Pantoténico/farmacología , Aceites de Plantas/farmacología , Ratas , Ratas Wistar , Clase Social , Población UrbanaRESUMEN
Tungiasis is a parasitic skin disease widespread in resource-poor urban and rural communities in Brazil. Inhabitants of an urban slum in Northeast Brazil were examined for the presence of tungiasis lesions and followed-up twice a week for a period of three weeks. Each time the number, stages, and topographic localization of lesions were recorded on a documentation sheet. The infestation rate (number of newly embedded sand fleas per individual and day) remained stable during the observation period. The infestation rate was significantly related to the intensity of infestation (total number of lesions present) (rho = 0.70, p < 0.0001) and the proportion of viable lesions (rho = 0.28, p < 0.0001). The results indicate that in an endemic area the infestation intensity and the proportion of viable lesions can be used as a proxy to assess the exposure of individuals at risk for tungiasis. Persistently high infestation rates during the transmission season favour the use of prevention measures against invading sand fleas (such as a repellent) rather than a drug to kill already embedded parasites.
Asunto(s)
Infestaciones Ectoparasitarias/epidemiología , Siphonaptera , Adolescente , Adulto , Animales , Brasil/epidemiología , Niño , Preescolar , Infestaciones Ectoparasitarias/parasitología , Enfermedades Endémicas , Femenino , Humanos , Lactante , Masculino , Densidad de Población , Pobreza , Índice de Severidad de la EnfermedadRESUMEN
Tungiasis is a parasitic skin disease widespread in resource-poor urban and rural communities in Brazil. Inhabitants of an urban slum in Northeast Brazil were examined for the presence of tungiasis lesions and followed-up twice a week for a period of three weeks. Each time the number, stages, and topographic localization of lesions were recorded on a documentation sheet. The infestation rate (number of newly embedded sand fleas per individual and day) remained stable during the observation period. The infestation rate was significantly related to the intensity of infestation (total number of lesions present) (rho = 0.70, p < 0.0001) and the proportion of viable lesions (rho = 0.28, p < 0.0001). The results indicate that in an endemic area the infestation intensity and the proportion of viable lesions can be used as a proxy to assess the exposure of individuals at risk for tungiasis. Persistently high infestation rates during the transmission season favour the use of prevention measures against invading sand fleas (such as a repellent) rather than a drug to kill already embedded parasites.