RESUMEN
Aedes aegypti mosquitoes are the primary vectors of numerous viruses that impact human health. As manipulation of reproduction has been proposed to suppress mosquito populations, elucidation of biological processes that enable males and females to successfully reproduce is necessary. One essential process is female sperm storage in specialized structures called spermathecae. Aedes aegypti females typically mate once, requiring them to maintain sperm viably to fertilize eggs they lay over their lifetime. Spermathecal gene products are required for Drosophila sperm storage and sperm viability, and a spermathecal-derived heme peroxidase is required for long-term Anopheles gambiae fertility. Products of the Ae. aegypti spermathecae, and their response to mating, are largely unknown. Further, although female blood-feeding is essential for anautogenous mosquito reproduction, the transcriptional response to blood-ingestion remains undefined in any reproductive tissue. We conducted an RNAseq analysis of spermathecae from unfed virgins, mated only, and mated and blood-fed females at 6, 24, and 72 h post-mating and identified significant differentially expressed genes in each group at each timepoint. A blood-meal following mating induced a greater transcriptional response in the spermathecae than mating alone. This study provides the first view of elicited mRNA changes in the spermathecae by a blood-meal in mated females.
Asunto(s)
Aedes/fisiología , Sangre/parasitología , Mosquitos Vectores/fisiología , Espermatozoides/metabolismo , Animales , Conducta Alimentaria , Femenino , Masculino , Conducta Sexual Animal , Transcriptoma , Fiebre Amarilla/parasitologíaRESUMEN
The landscape's structure can play a relevant role in epidemic patterns of arboviruses, influencing factors such as abundance, movement, and dispersal ability in arthropod vectors and vertebrate hosts, besides promoting alterations in the rate of potential infectious contacts between these organisms. In the Americas, yellow fever (YF) exhibits only the sylvatic cycle, in which the virus circulates in sylvatic areas among non-human primates, being transmitted by mosquitoes of the Haemagogus and Sabethes genera. In this study, we investigate some aspects of the landscape in relation to diversity and abundance of culicid species associated with YF transmission. Studies were performed in the Cantareira State Park, a remnant of the Atlantic Forest located in Greater Metropolitan São Paulo, Brazil, where the YF virus circulated recently with dozens of deaths in howler monkeys (Alouatta guariba), in addition to reported human cases. Mosquito collections were carried out monthly from February 2015 to April 2017. Mosquitoes were collected from three sites using battery-powered aspirator (12-volt battery), CDC, and Shannon traps for adults, and suction samplers and entomological spoons in breeding sites to collect immature forms. 703 mosquitoes belonging to 12 species of the Aedini and Sabethini tribes were collected. Aedes scapularis and Psorophora ferox exhibited higher abundance, while Haemagogus leucocelaenus, the main vector of YF in São Paulo state, showed lower abundance in all sampled areas. The site with longer edge between forest area and anthropic area presented more richness and abundance of YF vector species, while the site with larger forest cover area and shorter edges between forest and anthropic areas exhibited an inverse pattern. Statistically significant differences were observed between the composition of potential YF vector species among the investigated sites. Although Hg. leucocelaenus occurred in all sampled sites, the different patterns of distribution and abundance of other mosquitoes such as Aedes scapularis and Psorophora ferox suggest that these species may be involved in the transmission of sylvatic YF in the study area.
Asunto(s)
Culicidae/fisiología , Mosquitos Vectores/fisiología , Fiebre Amarilla/epidemiología , Virus de la Fiebre Amarilla , Animales , Océano Atlántico , Brasil/epidemiología , Ciudades , Culicidae/clasificación , Culicidae/virología , Entomología , Bosques , Humanos , Mosquitos Vectores/clasificación , Mosquitos Vectores/virología , Fiebre Amarilla/parasitologíaRESUMEN
A young Danish sailor died from yellow fever in Barbados in 1887. The Shipmaster's letter to the family with a description of the course of the disease, which has been preserved, is presented here together with a photo of the sailor and a painting of the Danish sailing-ship.
Asunto(s)
Fiebre Amarilla/historia , Barbados , Dinamarca , Resultado Fatal , Historia del Siglo XIX , Humanos , Personal Militar , Fiebre Amarilla/parasitología , Fiebre Amarilla/patologíaRESUMEN
Following reports of two autochthonous cases of sylvatic yellow fever in the State of São Paulo, Brazil, in 2000, entomological surveys were conducted with the objective of verifying the occurrence of vector species in forest environments close to or associated with riparian areas located in the western and northwestern regions of the State. Culicidae were captured in 39 sites distributed in four regions. Haemagogus leucocelaenus and Aedes albopictus were the most abundant species and were captured in all the regions studied. H. leucocelaenus was the most abundant species in the municipalities of Santa Albertina and Ouroeste, where the two cases of sylvatic yellow fever had been reported. Mosquitoes from the janthinomys/capricornii group were only found at eight sites in the São José do Rio Preto region, while Sabethes chloropterus was found at one site in Ribeirão Preto. H. leucocelaenus showed its capacity to adapt to a secondary and degraded environment. Our results indicate a wide receptive area for yellow fever transmission in the State of São Paulo, with particular emphasis on the possibility of H. leucocelaenus being involved in the maintenance of this sylvatic focus of the disease.
Asunto(s)
Culicidae/clasificación , Ecosistema , Insectos Vectores/clasificación , Fiebre Amarilla/parasitología , Animales , Brasil , HumanosRESUMEN
Because the potential urban yellow fever (YF) mosquito vectors Aedes aegypti and Ae. albopictus are at historical highs in Brazil, both in terms of density and geographical range, we assessed the risk of an urban YF epidemic in Brazil. We evaluated and confirmed in a laboratory setting the vector competence of Brazilian Ae. aegypti for a currently circulating strain of YF virus, and investigated the potential for Brazilian Ae. albopictus to transmit YF.
Asunto(s)
Aedes/virología , Brotes de Enfermedades , Insectos Vectores/virología , Fiebre Amarilla/epidemiología , Virus de la Fiebre Amarilla/aislamiento & purificación , Animales , Brasil/epidemiología , Humanos , Medición de Riesgo , Fiebre Amarilla/parasitología , Fiebre Amarilla/transmisiónRESUMEN
A little modification was made on the classical Borel tube, used for rearing isolated females of mosquitoes. The first studies were realized with the main Yellow fever vector, Haemagogus janthinomys, in Brazil. The results are: a better survival, as far as 72 days, a greater number of eggs, up to 80, and a shorter trophogonic cycle of 7-8 days. So, one can imagine more easily further studies about the vertical transmission of the YF virus by this important neo-tropical mosquito.
Asunto(s)
Femenino , Animales , Animales de Laboratorio/crecimiento & desarrollo , Culicidae/crecimiento & desarrollo , Entomología , Insectos Vectores/crecimiento & desarrollo , Fiebre Amarilla/parasitologíaRESUMEN
A little modification was made on the classical Borel tube, used for rearing isolated females of mosquitoes. The first studies were realized with the main Yellow fever vector, Haemagogus janthinomys, in Brazil. The results are: a better survival, as far as 72 days, a greater number of eggs, up to 80, and a shorter trophogonic cycle of 7-8 days. So, one can imagine more easily further studies about the vertical transmission of the YF virus by this important neo-tropical mosquito.
Asunto(s)
Animales de Laboratorio/crecimiento & desarrollo , Culicidae/crecimiento & desarrollo , Entomología/métodos , Insectos Vectores/crecimiento & desarrollo , Animales , Femenino , Fiebre Amarilla/parasitologíaRESUMEN
Adult female populations of Haemagogus leucocelaenus (Dyar and Shannon), the sylvan vector of yellow fever, were monitored weekly during 1981-82 by human collectors on the ground at Point Gourde in Chaguaramas Forest, 16 km west of Port-of-Spain, Trinidad. Hg.leucocelaenus showed only diurnal landing activity, from 06.00 to 18.00 hours (sunrise to sunset, universal time), with a single peak of activity between 10.00 and 14.00 hours. Densities of Hg.leucocelaenus during the wet season (May-November) were about double the level recorded during the dry season (December-April). Monthly parous rates averaged 53.9 percent (range 25-90 percent) and some females were up to five pars. Retained eggs (range 2-6, mean 4/female) were found in the ovaries of 0.34 percent of landing females, all of which had stage 1 ovarian follicles for the next gonotrophic cycle. Therefore blood-feeding is not inhibited by egg retention. Hg.leucocelaenus vector potential is reappraised in the light of these findings (AU)
Asunto(s)
Culicidae/metabolismo , Trinidad y Tobago , Paridad , Historia Reproductiva , Estadística/tendencias , Ciclos de Actividad/fisiología , Trinidad y Tobago , Fiebre Amarilla/parasitologíaRESUMEN
This small monograph is more than simply a collection of papers about yellow fever, it is also an expression of the origins of the Caribbean Epidemiology Centre (CAREC). Although many early accounts recorded in these pages cannot be scientifically authenticated, research this century suggests a cyclic pattern of epizootics with occasional outbreaks of human disease. The natural cycle of the disease involves monkeys and mosquitoes but mysteries remain to be elucidated, such as where does the virus go between epizootics. Transovarial transmission among mosquitoes may be important, while other mammalian and insect species might also be involved. Such questions are raised in these pages