RESUMEN
BACKGROUND: Ochlerotatus scapularis is a potential vector of filarias and arboviruses in the Neotropics. This species was once typically associated with sylvatic environments; however, cases of synanthropy and urbanization of this species have been increasingly reported in southeast Brazil. Despite the medical relevance of Oc. scapularis, its populational variability is not yet known. To our knowledge, this is the first report describing the morphological and genetic variabilities of this species. METHODS: Population samples were characterized using the cytochrome oxidase subunit I (COI) mitochondrial gene and wing geometrics. Adult mosquitoes were collected from five sampling sites from remnants of the Atlantic forest embedded in the urban or rural areas of southeast Brazil. RESULTS: In the 130 individuals analyzed, 46 COI haplotypes were detected. Haplotype diversity was high and ranged from 0.66 to 0.97. Six haplotypes were present in 61% of the individuals, whereas the remaining haplotypes were less frequent (39%). Wing shape was also highly polymorphic. Differentiation of populations across sampling sites according to genetic distances (Fst = -0.009 to 0.060) and morphological distances (Qst = 0.47) indicated that populations were not identical. No correlations were noted for phenetic and genetic diversities (p = 0.19) or for genetic or phenetic distances with geographical distances (p = 0.2 and p = 0.18, respectively). CONCLUSIONS: Our study results suggest that Oc. scapularis has a rich genetic patrimony, even though its habitat is fragmented. Implications of such genetic richness with respect to vectorial competence, plasticity, and ability to exploit urbanized areas need to be further investigated.
Asunto(s)
Variación Genética , Insectos Vectores , Ochlerotatus/anatomía & histología , Ochlerotatus/genética , Animales , Infecciones por Arbovirus/transmisión , Brasil , Ecosistema , Complejo IV de Transporte de Electrones/genética , Femenino , Filariasis/transmisión , Genética de Población , Genotipo , Proteínas Mitocondriales/genética , Ochlerotatus/clasificación , Fenotipo , Alas de Animales/anatomía & histologíaRESUMEN
In Nature, no individual can live in isolation; hence, living organisms are forced to interact with each other. This necessity has led many organisms to establish heterogeneous relations to enhance their ability to adapt to the environment, thus acquiring evolutionary advantages. These relationships are sometimes so intense, that on the long term the organisms may lose their individual identity. An example of these associations is the endosymbiotic ones, where eukaryote organisms generally harbor different prokaryote organisms. The endosymbiotic bacterium Wolbachia pipientis is a species described by Hertig and Wolbach in 1924. This microorganism can be isolated in a large variety of eukaryote organisms, with which it maintains different links. Until now, this species has only been described with 11 serogroups numbered from A to K within the Wolbachia genus. This work is intended to illustrate the relationship of Wolbachia pipientis with human pathogenic filaria and with arthropods, as well as to describe the implications of this bacterium in the treatment of filariasis. Finally, this work tries to describe recent studies that have targeted the use of artificially-created Wolbachia pipientis virulent strains that, once inoculated in infectious diseases-transmitting vectors, develop negative effects within them in order to, in this way, erradicate mosquito-transmitted infectious diseases for which no treatment is available at the moment or the prevention of its transmissibility has not been achieved.
En la naturaleza ningún individuo puede vivir de forma aislada, de tal forma que los organismos vivos se ven obligados a interactuar unos con otros. Esta necesidad ha llevado a que diferentes organismos establezcan relaciones heterogéneas para mejorar su capacidad de adaptación al medio, obteniendo así ventajas evolutivas. Estas relaciones a veces son tan intensas que a la larga los organismos pueden perder su identidad individual. Un ejemplo de estas asociaciones son las endosimbióticas, en las cuales generalmente organismos eucariotas albergan a diferentes organismos procariotas. La bacteria endosimbiótica Wolbachia pipientis es una especie descrita en 1924 por Hertig y Wolbach. Este microorganismo se puede aislar en gran variedad de organismos eucariotas, con los que mantiene diferentes vínculos. Hasta el momento solo se ha descrito esta especie con 11 serogrupos enumerados de la A a la K dentro del género Wolbachia. En este trabajo se pretende ilustrar la relación de Wolbachia pipientis con las filarias patógenas humanas y con los artrópodos, así como describir las implicaciones de esta bacteria en el tratamiento de las filariasis. Finalmente, se pretende exponer los estudios recientes que han apuntado el uso de cepas virulentas de Wolbachia pipientis creadas artificialmente que una vez inoculadas en los vectores transmisores de enfermedades desarrollan efectos negativos en estos, para de esa forma lograr la erradicación de enfermedades infecciosas transmitidas por mosquitos para las cuales de momento no existe tratamiento o no se ha logrado impedir su transmisibilidad.
Asunto(s)
Artrópodos/microbiología , Filariasis/prevención & control , Nematodos/microbiología , Simbiosis , Wolbachia , Animales , Filariasis/microbiología , Filariasis/transmisión , HumanosRESUMEN
This study assesses the ecological factors associated with microfilariae prevalence in wild populations of endangered flightless cormorants (Phalacrocorax harrisi) and Galápagos penguins (Spheniscus mendiculus). Prevalence values were tested for correlation with a large number of environmental variables, as modeled from weather station data and measured by satellite-borne sensors. Predictions were made based on the expected effects of climatic and landscape variables on sustained populations of arthropod vectors required for transmission of microfilariae. In general, findings were consistent with predictions in both cormorants and penguins; prevalence correlated positively with temperature, precipitation, and vegetation density, and negatively with measures of environmental variability. Resulting correlates were used to derive predictive distributions of prevalence values in cormorants throughout the archipelago. Evidence is presented implicating the mosquito Aedes taeniorhynchus as a likely vector. Knowledge of environmental variables that predict risk of disease transmission by arthropod vectors may be useful in control measures should novel pathogens be introduced to the ecosystem.
Asunto(s)
Enfermedades de las Aves/epidemiología , Filariasis/veterinaria , Filarioidea/aislamiento & purificación , Spheniscidae/parasitología , Aedes/parasitología , Animales , Enfermedades de las Aves/parasitología , Enfermedades de las Aves/transmisión , Aves , Ecuador/epidemiología , Filariasis/epidemiología , Filariasis/transmisión , Filarioidea/clasificación , Filarioidea/genética , Insectos Vectores/parasitología , Microfilarias/aislamiento & purificación , PrevalenciaRESUMEN
This work describes the occurrence of the helminth Stephanofilaria spp in ulcerative nodular dermatitis in humans. The ulcers observed presented a variety of sizes and some years of existence. It is believed that the presence of this parasite, which affects several domestic and wild animal species, may harm human health through lesions produced in venous and lymphatic vessels that reduce blood circulation and retard the healing process. The cycle of this parasite in humans is also described.
Asunto(s)
Filariasis/parasitología , Filarioidea , Enfermedades Cutáneas Parasitarias/parasitología , Úlcera Cutánea/parasitología , Adulto , Animales , Femenino , Filariasis/patología , Filariasis/transmisión , Filarioidea/clasificación , Filarioidea/fisiología , Humanos , Recién Nacido , Persona de Mediana Edad , Enfermedades Cutáneas Parasitarias/patología , Enfermedades Cutáneas Parasitarias/transmisión , Úlcera Cutánea/patologíaRESUMEN
Descreve-se aqui o encontro do helminto Stephanofilaria spp., em dermatite nodular ulcerativa em seres humanos, sendo as ulceras pesquisadas de dimensões variadas e com alguns anos de existência. Acredita-se que, a presença desse parasita, que afeta diversas espécies de animais domésticos e silvestres, possa agravar o quadro com as lesões produzidas nos vasos venosos e linfáticos, reduzindo a circulação, retardando a cicatrização. O ciclo deste parasita no ser humano, também é descrito.
This work describes the occurrence of the helminth Stephanofilaria spp in ulcerative nodular dermatitis in humans. The ulcers observed presented a variety of sizes and some years of existence. It is believed that the presence of this parasite, which affects several domestic and wild animal species, may harm human health through lesions produced in venous and lymphatic vessels that reduce blood circulation and retard the healing process. The cycle of this parasite in humans is also described.
Asunto(s)
Humanos , Animales , Femenino , Recién Nacido , Adulto , Persona de Mediana Edad , Filarioidea , Filariasis/parasitología , Enfermedades Cutáneas Parasitarias/parasitología , Úlcera Cutánea/parasitología , Filariasis/patología , Filariasis/transmisión , Filarioidea/clasificación , Filarioidea/fisiología , Enfermedades Cutáneas Parasitarias/patología , Enfermedades Cutáneas Parasitarias/transmisión , Úlcera Cutánea/patologíaRESUMEN
The infective larva of Litomosoides yutajensis Guerrero et al., 2003, a parasite of the bat Pteronotus pamellii, is described; it is distinct from congeneric infective larvae by the absence of caudal lappets. The life cycles of five other species of Litomosoides are known; three are parasites of rodents, one of a marsupial and one of a bat. As with these species, the experimental vector of L. yutoajensis used was the macronyssid mite Ornithonyssus bacoti. In nature, the main vectors are probably other macronyssids but transmission by O. bacoti, with its large host-range, could account for the characteristic host-switchings in the evolution of Litomosoides. Unlike the murine model L. sigmodontis Chandler, 1931, L. yutajensis is devoid of the endosymbiontic bacteria Wolbachia and may be of great interest.
Asunto(s)
Quirópteros/parasitología , Filariasis/veterinaria , Filarioidea/clasificación , Estadios del Ciclo de Vida , Animales , Vectores Arácnidos/parasitología , Femenino , Filariasis/parasitología , Filariasis/transmisión , Filarioidea/anatomía & histología , Filarioidea/crecimiento & desarrollo , Interacciones Huésped-Parásitos , Larva , Masculino , Ácaros/parasitología , Filogenia , Especificidad de la Especie , VenezuelaAsunto(s)
Humanos , Masculino , Femenino , Filariasis/diagnóstico , Filariasis/prevención & control , Filariasis/transmisiónAsunto(s)
Masculino , Femenino , Humanos , Filariasis/diagnóstico , Filariasis/prevención & control , Filariasis/transmisiónRESUMEN
Lymphatic filariasis and malaria are endemic in Guyana, South America. To determine the prevalence of concomitant infections, we conducted a 1-year survey of febrile patients attending the malaria (day) and filariasis (night) clinics in Georgetown. In all, 1278 thick blood smears were collected; 769 for filariasis, of which 103 were positive for Wucheria bancrofti, and three for both W. bancrofti and malaria parasites; and 509 for malaria, 21 of which tested positive for malaria and 17 for both malaria and filariasis. The age groups and sex of the infected persons with malaria and W. bancrofti are descibed. These results suggest that the incidence of concomitant infections in Guyana may be quite low but efforts should be made to reduce the disease burden in Georgetown, Guyana (AU)
Asunto(s)
Gatos , Perros , Humanos , Malaria/prevención & control , Malaria/epidemiología , Malaria/parasitología , Plasmodium malariae/parasitología , Malaria Vivax/parasitología , Malaria Falciparum/parasitología , Guyana , Síntomas Concomitantes , Infecciones , Prevalencia , Filariasis/parasitología , Filariasis/transmisión , Filariasis/diagnósticoRESUMEN
The efficacy of Bacillus sphaericus 2362 against Culex quinquefasciatus was tested in 1991-94 in a major Brazilian endemic zone for bancroftian filariasis. Continuous selection pressure against the mosquito population was sustained for 18 months through treatment of 2500 potential breeding sites occurring within a 5.7-km2 urban area in the Metropolitan Region of Recife. The impact of this control intervention was evaluated by comparing entomological indices with those from an untreated area. Application of the larvicide kept the Cx. quinquefasciatus population density significantly lower when compared to the untreated area, despite some operational difficulties. Adult densities remained lower for at least 5 months after spraying ceased. Pre-trial microfilaria rates from the untreated and operational area were 13.1% and 7.2%, respectively. A 60% reduction in human exposure to infective bites was recorded as a consequence of this vector population control.
Asunto(s)
Culex/parasitología , Filariasis/prevención & control , Control Biológico de Vectores/métodos , Animales , Brasil/epidemiología , Vectores de Enfermedades , Filariasis/parasitología , Filariasis/transmisión , Humanos , Control de Mosquitos/métodos , Estaciones del Año , Resultado del Tratamiento , Salud UrbanaAsunto(s)
Enfermedades de la Conjuntiva/parasitología , Filariasis/transmisión , Wuchereria bancrofti , Animales , Niño , Femenino , Haití , HumanosRESUMEN
A study was conducted to determine the susceptibility of local strains of Culex quinquefasciatus and Aedes aegypti to infection with the strain of Wuchereria bancrofti that occurs in Maceió, State of Alagoas, Brazil. Cx. quinquefasciatus blood fed simultaneously on the same microfilariae carrier ingested more blood and 2-3x more microfilariae than Ae. aegypti. Survival rates of both species of insects living for 21 days after blood feeding on microfilaraemic patients were not significantly different from the survival rates of mosquitoes that blood fed on amicrofilaraemic individuals. W. bancrofti parasites underwent normal development in Cx. quinquefasciatus, with third stage larvae first being recorded on the 11th day post infection, and their numbers increasing thereafter. Development of filariae in Ae. aegypti did not proceed beyond the first larval stage, and there was a progressively increasing number of non-viable larvae with the passage of time. It is concluded that Ae. aegypti is not involved in the transmission of W. bancrofti in Maceió.
Asunto(s)
Animales , Aedes/parasitología , Culex/parasitología , Wuchereria bancrofti/patogenicidad , Brasil/epidemiología , Filariasis/transmisiónRESUMEN
Females of laboratory-reared Culex quinquefasciatus were allowed to take blood meals on individuals with low (1-100 microfilariae/ml of peripheral blood), moderate (101-500 microfilariae/ml), and high (> 500 microfilariae/ml) microfilaremia. The mosquitoes ingested 1.39-3.80 microl of blood and infective third-stage (L3) larvae were first recorded 13-14 days after the infecting blood meal. The number of microfilariae ingested by mosquitoes was proportional to the density of microfilariae in the peripheral blood of the human subjects, but with a concentration factor of up to 6.5 times the expected number. Survival of mosquitoes was not influenced by the density of microfilariae in the peripheral blood of infected individuals. Infectivity indices were proportional to microfilaremia in human subjects. The number of L3 larvae/female (intensity of infection) was not influenced by individual microfilaremia. The highest vector efficiency and the best experimental infection index were recorded in mosquitoes that blood fed on individuals with moderate microfilaremia. The results are discussed in relation to the transmission on Bancroftian filariasis in the study area.
Asunto(s)
Culex/parasitología , Filariasis/parasitología , Insectos Vectores/parasitología , Parasitemia/parasitología , Wuchereria bancrofti/fisiología , Adolescente , Adulto , Animales , Brasil , Femenino , Filariasis/sangre , Filariasis/transmisión , Humanos , Microfilarias/crecimiento & desarrollo , Microfilarias/fisiología , Parasitemia/sangre , Parasitemia/transmisión , Wuchereria bancrofti/crecimiento & desarrolloRESUMEN
The objective of this study was to identify biological and social risk factors for the occurrence of microfilaraemia in a population of 1464 children of both sexes aged 5-14 years, living in two highly endemic areas of Recife a city in the northeast of Brazil. A survey was performed from December 1990 to July 1991 and the microfilaraemia was examined by the thick-drop technique using 45 microliters of peripheral blood. Information was obtained about use of bednet, length of time living in area and number of occupants per household. Risk was quantified by the crude and adjusted Odds Ratio. The 95 per cent confidence interval, Likelihood Ratio Statistics, and P value were used to test the statistical significance. An association was established between microfilaraemia in children and adolescents, and age, number of individuals per household, the presence of microfilaraemic adults in the household, length of time living in the area, and bednet use. Maternal microfilaraemia was not found to be a risk factor for the occurrence of microfilaraemia in offspring. These results allow the identification of children with a greater risk of microfilaraemia. In addition, these findings highlight the role of the household environment in the transmission process.
Asunto(s)
Enfermedades Endémicas/estadística & datos numéricos , Filariasis/epidemiología , Wuchereria bancrofti/aislamiento & purificación , Adolescente , Adulto , Distribución por Edad , Animales , Brasil/epidemiología , Niño , Preescolar , Intervalos de Confianza , Transmisión de Enfermedad Infecciosa , Femenino , Filariasis/diagnóstico , Filariasis/transmisión , Encuestas Epidemiológicas , Humanos , Incidencia , Funciones de Verosimilitud , Masculino , Análisis Multivariante , Oportunidad Relativa , Factores de Riesgo , Población Rural , Distribución por SexoRESUMEN
Foi feita revisäo dos estudos sobre a distribuiçäo geográfica e prevalência da filariose linfática bancroftiana no Brasil. Entre 1951 a 1958 foram realizados inquéritos hemoscópicos e entomológicos no país, sendo a transmissäo autóctone comprovada em apenas 11 Municípios: Ponta Grossa (SC), 14,5 por cento; Belém (PA), 9,8 por cento; Barra de Laguna (SC), 9,4 por cento; Recife (PE), 6,9 por cento; Castro Alves (BA), 5,9 por cento; Florianópolis (SC), 1,4 por cento; Säo Luís (MA), 0,6 por cento; Salvador (BA), 0,4 por cento; Maceió (AL), 0,3 por cento; Manaus (AM), 0,2 por cento e Porto Alegre (RS), 0,1 por cento. A distribuiçaö da parasitose era urbana e focal, principamente em cidades litorânes. As açöes de controle implementadas levaram a uma precíavel queda nas taxas de microfilarêmicos sendo consideradas, a partir de entäo, áreas endemicas para Filariose linfática no Brasil somente as cidades de Belém e Recife. Estudos recentes mostram a transmissäo ativa de parasitose, com prevalências superiores às detectadas no passado, em Maceió, cujo foco era considerado extinto, e em Recife. O conhecimento da situaçäo atual de bancroftose no Brasil é de fundamental importância para a implementaçäo de açöes de controle da endemia envolvendo o Ministério da Saúde e órgäo de saúde pública.
Asunto(s)
Características de la Residencia , Filariasis Linfática/epidemiología , Filariasis/transmisiónRESUMEN
We examined the periodicity and intravascular distribution of Wuchereria bancrofti microfilariae (mf) and determined the effect of these parasite properties on the accuracy of blood filming and filtration methods for diagnosis of bancroftian filariasis in the endemic area of Recife, Brazil. Microfilariae in both venous and capillary blood exhibited a nocturnal periodicity pattern with a relatively high amplitude. Overall, capillary blood contained approximately 1.25 times the number of mf present at the same time in the same volume of venous blood. However, the ratio of mf present in capillary and venous blood varied over a 24-hour period, so that the fewest mf were present in the capillary bed of the skin at the time when biting activity of the local Culex vector is the lowest. Twenty or 60 microliters blood films did not reliably detect carriers with fewer than 100 or 60 mf/ml venous blood, respectively, and were thus inadequate for the identification of low density mf carriers. In contrast, all carriers with > 1 mf/20 or 60 microliters blood smear at night could be identified during daytime hours by filtration of 1 micromilligram venous blood.
Asunto(s)
Recolección de Muestras de Sangre/métodos , Culex , Filariasis/sangre , Filariasis/parasitología , Insectos Vectores , Periodicidad , Wuchereria bancrofti , Animales , Brasil , Capilares , Culex/fisiología , Conducta Alimentaria , Filariasis/transmisión , Humanos , Insectos Vectores/fisiología , Microfilarias/fisiología , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Factores de Tiempo , VenasRESUMEN
Several bacterial and parasite transfusion-transmitted diseases have been described in the medical literature. This review deals with the main bacterial (Syphilis, Lyme disease, Gram positive and Gram negative agents), parasite (Chagas disease, malaria, leishmaniasis, toxoplasmosis and babesiosis) and rickettsial diseases that are carried by blood products. Preventional aspects (e.g. storage, screening tests, use of leukocyte-depleted components), diagnosis, geographical distribution and the incidence of these transfusional hazards are also discussed.
Asunto(s)
Infecciones Bacterianas/transmisión , Transfusión de Componentes Sanguíneos/efectos adversos , Enfermedades Parasitarias/transmisión , Babesiosis/transmisión , Infecciones Bacterianas/prevención & control , Donantes de Sangre , Filariasis/transmisión , Humanos , Leishmaniasis/transmisión , Enfermedad de Lyme/transmisión , Malaria/transmisión , Enfermedades Parasitarias/prevención & control , Sífilis/transmisión , Toxoplasmosis/transmisión , Tripanosomiasis/transmisiónRESUMEN
La transfusión de sangre y sus componentes, indicada de manera sensata y precisa, es de enorme ayuda terapéutica, pero también conlleva riesgos, por lo cual debe realizarse un control estricto en la selección de donadores, en la recolección, conservación y transporte de la sangre. Las infecciones son uno de los riesgos de la transfusión sanguínea; en el presente trabajo nos referimos específicamente a los parásitos que pueden ser transmitidos por esta vía y la manera de evitarlo
Asunto(s)
Bancos de Sangre/normas , Donantes de Sangre/clasificación , Enfermedad de Chagas/transmisión , Cloroquina/administración & dosificación , Ensayo de Inmunoadsorción Enzimática , Filariasis/transmisión , Control de Infecciones , Leishmaniasis Visceral/transmisión , Malaria/transmisión , Toxoplasmosis/transmisión , Transfusión SanguíneaRESUMEN
A Filariose bancroftiana esta se disseminado em areas humanas de regioes endemicas como no Recife, nordeste do Brasil, onde se constitui em um problema de microfilaremia e doenca filareal em duas areas urbanas do Recife, estudando sua associacao com caracteristicas individuais e variaveis realacionadas ao contacto com valores. O inquerito parasitologico foi realizado atraves de um censo "porta-a-porta" e a pesquisa de microfilarias foi efetuada pela tecnica da gota espessa utilizando 45µ de sangue capilar entre 20:00 e 24:00 horas...
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Adolescente , Adulto , Persona de Mediana Edad , Filariasis/epidemiología , Vectores de Enfermedades/clasificación , Wuchereria bancrofti/aislamiento & purificación , Brasil , Filariasis/transmisión , Encuestas Epidemiológicas , Factores de Riesgo , UrbanizaciónRESUMEN
Integrated control measures against Culex quinquefasciastus have been implemented in a pilot urban area in Recife, Brazil. About 3,000 breeding sites found within the operational area were responsible for very high mosquito densities recorded during the pretrial period. Physical control measures have been applied to cess pits before starting a series of 37 treatments of the other sites with Bacillus sphaericus strain 2362, over 27 months. In spite of the difficulties due to environmental conditions, very significant reductions in preimaginal population of C. quinquefasciatus were achieved and, as a consequence, low adult mosquito densities were maintained for a relatively long period of time. Entomological and environmental data gathered in this pilot project can contribute to design an integrated mosquito control program in Recife city.