Time filter

Source Type

Maciel-de-Freitas R.,Laboratorio Of Transmissores Of Hematozoarios | Aguiar R.,Servico de Jornalismo e Comunicacao | Bruno R.V.,Laboratorio Of Biologia Molecular Of Insetos | Guimaraes M.C.,Institute Comunicacao e Informacao Cientifica e Tecnologica | And 5 more authors.
Memorias do Instituto Oswaldo Cruz | Year: 2012

In this opinion paper, we discuss the potential and challenges of using the symbiont Wolbachia to block mosquito transmitted diseases such as dengue, malaria and chikungunya in Latin America.


Monteiro de Barros F.S.,Federal University of Pernambuco | Honorio N.A.,Laboratorio Of Transmissores Of Hematozoarios
Journal of Vector Ecology | Year: 2011

Malaria has reemerged in tropical regions with rapid population growth and deforestation. The dynamics of malaria transmission in agricultural settlements of the Amazon have been poorly defined. We studied the spatial distribution of malaria incidence in Roraima, Brazil, using multi regression analysis on 12 parameters that described social, housing, and behavioral variables. Malaria cases were associated with the proximity of Anopheles darlingi breeding sites, the main vector in these areas. During the dry season, transmission was enhanced near a temporary river. Cases occurred throughout the year near fish-farming dams. Epidemiological models derived from urban or riverine malaria are probably inadequate for describing disease transmission in agricultural settlements, where cases are clustered near breeding sites, while the majority of the population remains unaffected. Identification of these areas, associated with residual insecticide spraying or surveillance, may considerably decrease the costs of control efforts. © 2011 The Society for Vector Ecology.


PubMed | Secretaria de Vigilancia em Saude, Laboratorio Of Fisiologia E Controle Of Artropodes Vetores, Institute Pesquisas Cientificas e Tecnologicas do Estado do Amapa IEPA, Programa de Computacao Cientifica and 2 more.
Type: Comparative Study | Journal: PLoS neglected tropical diseases | Year: 2015

The mosquito Aedes aegypti, vector of dengue, chikungunya and yellow fever viruses, is an important target of vector control programs in tropical countries. Most mosquito surveillance programs are still based on the traditional household larval surveys, despite the availability of new trapping devices. We report the results of a multicentric entomological survey using four types of traps, besides the larval survey, to compare the entomological indices generated by these different surveillance tools in terms of their sensitivity to detect mosquito density variation.The study was conducted in five mid-sized cities, representing variations of tropical climate regimens. Surveillance schemes using traps for adults (BG-Sentinel, Adultrap and MosquiTRAP) or eggs (ovitraps) were applied monthly to three 1 km(2) areas per city. Simultaneously, larval surveys were performed. Trap positivity and density indices in each area were calculated and regressed against meteorological variables to characterize the seasonal pattern of mosquito infestation in all cities, as measured by each of the four traps.The House Index was consistently low in most cities, with median always 0. Traps rarely produced null indices, pointing to their greater sensitivity in detecting the presence of Ae. aegypti in comparison to the larval survey. Trap positivity indices tend to plateau at high mosquito densities. Despite this, both indices, positivity and density, agreed on the seasonality of mosquito abundance in all cities. Mosquito seasonality associated preferentially with temperature than with precipitation even in areas where temperature variation is small.All investigated traps performed better than the House Index in measuring the seasonal variation in mosquito abundance and should be considered as complements or alternatives to larval surveys. Choice between traps should further consider differences of cost and ease-of-use.


Lima-Camara T.N.,Programa de Computacao Cientifica | Codeco C.T.,Programa de Computacao Cientifica | Honorio N.A.,Laboratorio Of Transmissores Of Hematozoarios | Bruno R.V.,Instituto Oswaldo Cruz Fiocruz | And 2 more authors.
Memórias do Instituto Oswaldo Cruz | Year: 2013

Dengue is one of the world's most important mosquito-borne diseases and is usually transmitted by one of two vector species: Aedes aegypti or Aedes albopictus . These two diurnal mosquitoes are frequently found coexisting in similar habitats, enabling interactions between adults, such as cross-mating. The objective of this study was to assess cross-mating between Ae. aegypti females and Ae. albopictus males under artificial conditions and evaluate the locomotor activity of Ae. aegypti virgin females injected with male accessory gland (MAG) homogenates to infer the physiological and behavioural responses to interspecific mating. After seven days of exposure, 3.3-16% of Ae. aegypti females mated with Ae. albopictus males. Virgin Ae. aegypti females injected with conspecific and heterospecific MAGs showed a general decrease in locomotor activity compared to controls and were refractory to mating with conspecific males. The reduction in diurnal locomotor activity induced by injections of conspecific or heterospecific MAGs is consistent with regulation of female reproductive activities by male substances, which are capable of sterilising female Ae. aegypti through satyrisation by Ae. albopictus.


PubMed | Secretaria de Vigilancia em Saude, Laboratorio Of Biologia Molecular Of Flavivirus, Programa de Computacao Cientifica, Laboratorio Of Fisiologia E Controle Of Artropodes Vetores and 2 more.
Type: | Journal: Memorias do Instituto Oswaldo Cruz | Year: 2014

Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities. When the same samples were inspected in the field and in the laboratory, large differences were noted in the total number of mosquitoes recorded and in the number of specimens identified as Ae. aegypti by both procedures. Although field identification has the potential to speed vector surveillance, these results point to uncertainties in the evaluated protocol.


PubMed | Secretaria de Vigilancia em Saude, Laboratorio Of Biologia Molecular Of Flavivirus, Programa de Computacao Cientifica, Laboratorio Of Fisiologia E Controle Of Artropodes Vetores and 2 more.
Type: Journal Article | Journal: Memorias do Instituto Oswaldo Cruz | Year: 2014

Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities. When the same samples were inspected in the field and in the laboratory, large differences were noted in the total number of mosquitoes recorded and in the number of specimens identified as Ae. aegypti by both procedures. Although field identification has the potential to speed vector surveillance, these results point to uncertainties in the evaluated protocol.


Codeco C.T.,Programa de Computacao Cientifica | Lima A.W.S.,Laboratorio Of Fisiologia E Controle Of Artropodes Vetores | Araujo S.C.,Laboratorio Of Fisiologia E Controle Of Artropodes Vetores | Lima J.B.P.,Laboratorio Of Fisiologia E Controle Of Artropodes Vetores | And 6 more authors.
PLoS Neglected Tropical Diseases | Year: 2015

The mosquito Aedes aegypti, vector of dengue, chikungunya and yellow fever viruses, is an important target of vector control programs in tropical countries. Most mosquito surveillance programs are still based on the traditional household larval surveys, despite the availability of new trapping devices. We report the results of a multicentric entomological survey using four types of traps, besides the larval survey, to compare the entomological indices generated by these different surveillance tools in terms of their sensitivity to detect mosquito density variation. The study was conducted in five mid-sized cities, representing variations of tropical climate regimens. Surveillance schemes using traps for adults (BG-Sentinel, Adultrap and MosquiTRAP) or eggs (ovitraps) were applied monthly to three 1 km2 areas per city. Simultaneously, larval surveys were performed. Trap positivity and density indices in each area were calculated and regressed against meteorological variables to characterize the seasonal pattern of mosquito infestation in all cities, as measured by each of the four traps. The House Index was consistently low in most cities, with median always 0. Traps rarely produced null indices, pointing to their greater sensitivity in detecting the presence of Ae. aegypti in comparison to the larval survey. Trap positivity indices tend to plateau at high mosquito densities. Despite this, both indices, positivity and density, agreed on the seasonality of mosquito abundance in all cities. Mosquito seasonality associated preferentially with temperature than with precipitation even in areas where temperature variation is small. All investigated traps performed better than the House Index in measuring the seasonal variation in mosquito abundance and should be considered as complements or alternatives to larval surveys. Choice between traps should further consider differences of cost and ease-of-use. © 2015 Codeço et al.


Maciel-de-Freitas R.,Laboratorio Of Transmissores Of Hematozoarios | Sylvestre G.,Laboratorio Of Transmissores Of Hematozoarios | Gandini M.,Laboratorio Of Imunologia Viral | Koella J.C.,University of Neuchatel
PLoS ONE | Year: 2013

Background:Dengue virus (DENV) is transmitted by Aedes aegypti, a species that lives in close association with human dwellings. The behavior of DENV-infected mosquitoes needs further investigation, especially regarding the potential influence of DENV on mosquito biting motivation and avidity.Methodology/Principal findings:We orally challenged 4-5 day-old Ae. aegypti females with a low passage DENV serotype -2 (DENV-2) to test whether the virus influences motivation to feed (the likelihood that a mosquito obtains a blood-meal and the size of its blood meal) and avidity (the likelihood to re-feed after an interrupted first blood-meal). To assay motivation, we offered mosquitoes an anesthetized mouse for 2, 3, 4 or 5 minutes 7 or 14 days after the initial blood meals and measured the time they started feeding. 60.5% of the unexposed mosquitoes fed on the mouse, but only 40.5% of the positive ones did. Exposed but negative mosquitoes behaved similarly to unexposed ones (55.0% feeding). Thus DENV-2 infection decreased the mosquitoes' motivation to feed. To assay avidity, we offered the same mosquitoes a mouse two hours after the first round of feeding, and we measured the time at which they started probing. The exposed (positive or negative) mosquitoes were more likely to re-feed than the unexposed ones and, in particular, the size of the previous blood-meal that kept mosquitoes from re-feeding was larger in the exposed than in the unexposed mosquitoes. Thus, DENV-2 infection increased mosquito avidity.Conclusions/Significance:DENV-2 significantly decreased the mosquitoes' motivation to feed, but increased their avidity (even after taking account the amount of blood previously imbibed). As these are important components of transmission, we expect that the changes of the blood-feeding behaviour impact the vectorial capacity Ae. aegypti for dengue. © 2013 Maciel-de-Freitas et al.


PubMed | Escola Nacional de Saude Publica, Programa de Computacao Cientifica, Institute Pesquisas Clinicas Evandro Chagas, Laboratorio Of Transmissores Of Hematozoarios and 2 more.
Type: | Journal: Infection ecology & epidemiology | Year: 2014

The potential influence of high-vector-density environments where people are supposedly more exposed to mosquito bites may have a relation to the clinical severity of dengue fever, an association that has been poorly discussed in the literature.This study aimed at analyzing the association between anthropic environmental factors, particularly those related to the conditions of domicile and peridomicile, and the occurrence of severe dengue cases during the 2008 epidemic in the state of Rio de Janeiro.We conducted a retrospective case-control study with a sample of 88 severe patients aged 2-18. They were selected through chart review in four childrens tertiary care centers. The 367 controls were neighbors of the cases, paired by age. Data were collected through interviews and systematic assessment of house conditions as well as peridomicile area conditions, and they were later analyzed by conditional logistic regression.The presence of three or more high-volume capacity containers, which were without a lid or were inadequately sealed (water tanks, wells, cisterns, cement tanks, and pools), was significantly more frequent in households with severe cases when compared with households of controls (OR=1.6; CI 95%=1.36-20.01; p=0.015).The presence of such larger reservoirs that could potentially produce more adult forms of the vector is consistent with a situation where people are more exposed to mosquito bites, and consequently are more prone to have multiple infections over a short period of time.The emergence of severe dengue cases in a high-transmission context underpins the importance of constant vigilance and interventions in those types of reservoirs, which result from precarious household structures and irregular water supply services.


PubMed | Laboratorio Of Transmissores Of Hematozoarios and Programa de Computacao Cientifica
Type: Journal Article | Journal: Annals of the Entomological Society of America | Year: 2016

Water accumulating in the axils of bromeliads provides habitat for numerous invertebrates, frequently among them, immature mosquitoes. To evaluate mosquito richness in bromeliads and the relationship between mosquito presence and biotic and abiotic variables, we performed a study in the Parque Nacional do Itatiaia, Rio de Janeiro, Brazil. Mosquitoes of genus

Loading Laboratorio Of Transmissores Of Hematozoarios collaborators
Loading Laboratorio Of Transmissores Of Hematozoarios collaborators