Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.132
Filtrar
1.
Artículo en Inglés | MEDLINE | ID: mdl-32491144

RESUMEN

Eleven lactating women were inadvertently vaccinated with 17DD yellow fever vaccine in a small city of Sao Paulo State, Brazil. Their infants were being exclusively breast-fed and the breastfeeding was interrupted for 10 days. Serum and breastmilk were collected from the vaccinated mothers and tested for the presence of genomic RNA of the vaccine strain 8, 10 and 15 days after vaccination. Viral RNA was not detected in any of the serum and human milk samples tested and the infants remained asymptomatic. Our result strengthens the effectineness of stopping breastfeeding for 10 days after the inadvertent yellow fever vaccination of lactating women.


Asunto(s)
Lactancia Materna/efectos adversos , Leche Humana/virología , Vacuna contra la Fiebre Amarilla/efectos adversos , Fiebre Amarilla/prevención & control , Virus de la Fiebre Amarilla/inmunología , Anticuerpos Antivirales/sangre , Antígenos Virales/sangre , Brasil , Femenino , Humanos , Recién Nacido , ARN Viral/sangre , Fiebre Amarilla/transmisión , Vacuna contra la Fiebre Amarilla/administración & dosificación
3.
Mem Inst Oswaldo Cruz ; 115: e190437, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32428083

RESUMEN

BACKGROUND Aedes aegypti and Aedes albopictus are the most important arbovirus vectors in the world. OBJECTIVES This study aimed to investigate and compare the infestation pattern of these species in a neighbourhood of Recife, Brazil, endemic for arboviruses in 2005 (T1) and 2013 (T2). METHODS Infestation, distribution and relative abundance of these sympatric species were recorded by egg collection using a network of 59 sentinel ovitraps (s-ovt) at fixed sampling stations for 12 months in T1 and T2. FINDINGS A permanent occupation pattern was detected which was characterised by the presence of egg-laying females of one or both species with a high ovitrap positivity index (94.3 to 100%) throughout both years analysed. In terms of abundance, the total of eggs collected was lower (p < 0.005) in T2 (146,153) than in T1 (281,103), although ovitraps still displayed a high index of positivity. The spatial distribution showed the presence of both species in 65.1% of the 148 s-ovt assessed, while a smaller number of traps exclusively contained Ae. aegypti (22%) or Ae. albopictus (13.2%) eggs. MAIN CONCLUSIONS Our comparative analysis demonstrated the robustness of the spatial occupation and permanence of Ae. aegypti and Ae. albopictus populations in this endemic urban area.


Asunto(s)
Aedes/clasificación , Mosquitos Vectores/clasificación , Aedes/fisiología , Distribución Animal , Animales , Infecciones por Arbovirus/epidemiología , Infecciones por Arbovirus/transmisión , Brasil/epidemiología , Enfermedades Endémicas , Femenino , Masculino , Mosquitos Vectores/fisiología , Oviposición , Densidad de Población , Estaciones del Año
4.
PLoS Negl Trop Dis ; 14(5): e0008320, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32392224

RESUMEN

BACKGROUND: The global spread of Aedes albopictus has exposed new geographical areas to the risk of dengue and chikungunya virus transmission. Several autochthonous transmission events have occurred in recent decades in Southern Europe and many indicators suggest that it will become more frequent in this region in the future. Environmental, socioeconomic and climatic factors are generally considered to trigger the emergence of these viruses. Accordingly, a greater knowledge of the determinants of this emergence in a European context is necessary to develop adapted surveillance and control strategies, and public health interventions. METHODOLOGY/PRINCIPAL FINDINGS: Using French surveillance data collected from between 2010 and 2018 in areas of Southern France where Ae. albopictus is already established, we assessed factors associated with the autochthonous transmission of dengue and chikungunya. Cases leading to autochthonous transmission were compared with those without subsequent transmission using binomial regression. We identified a long reporting delay (≥ 21 days) of imported cases to local health authorities as the main driver for autochthonous transmission of dengue and chikungunya in Southern France. The presence of wooded areas around the cases' place of residence and the accumulation of heat during the season also increased the risk of autochthonous arbovirus transmission. CONCLUSIONS: Our findings could inform policy-makers when developing strategies to the emerging threats of dengue and chikungunya in Southern Europe and can be extrapolated in this area to other viruses such as Zika and yellow fever, which share the same vector. Furthermore, our results allow a more accurate characterization of the environments most at risk, and highlight the importance of implementing surveillance systems which ensure the timely reporting and of imported cases and swift interventions.


Asunto(s)
Aedes/crecimiento & desarrollo , Fiebre Chikungunya/transmisión , Dengue/transmisión , Transmisión de Enfermedad Infecciosa , Mosquitos Vectores/crecimiento & desarrollo , Animales , Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Femenino , Francia/epidemiología , Humanos , Masculino
5.
PLoS Negl Trop Dis ; 14(5): e0008250, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32401756

RESUMEN

BACKGROUND: The French overseas Territory of the Wallis and Futuna Islands has been affected by several dengue epidemics. Aedes polynesiensis is the main mosquito vector described in this territory. Other Aedes species have been reported, but recent entomological data are missing to infer the presence of other potential arbovirus vectors and to assess the entomological risk factors for transmission of arboviral diseases. METHODOLOGY/ PRINCIPAL FINDINGS: An entomological prospective study was conducted on the three main islands of the territory to determine the presence and distribution of Aedes spp. Larvae, pupae and adult mosquitoes were collected from 54 sampling points in different environments, with a final sampling of 3747 immature stages and 606 adults. The main identified breeding sites were described. Ae. polynesiensis was found in every sampled site in peridomestic and wild habitats. Ae. aegypti was only found on the island of Wallis in peridomestic environments with a limited distribution. Two other Aedes species endemic to the Pacific were recorded, Aedes oceanicus and Aedes futunae. To evaluate the ability of local Ae. polynesiensis to transmit the chikungunya virus (CHIKV), two field populations were analyzed for vector competence using experimental oral exposure of females to CHIKV and infection, dissemination and transmission assays. Results showed that both populations of Ae. polynesiensis were competent for CHIKV (30% at 7 days post-infection). CONCLUSIONS/SIGNIFICANCE: This study showed the ubiquitous distribution and abundance of Ae. polynesiensis on the three islands and demonstrated that local populations were able to transmit CHIKV. Combined with the presence and expansion of Ae. aegypti on the main island of Wallis, these data highlight the risk of transmission of arboviral diseases in the territory of Wallis and Futuna and provide relevant information for entomological surveillance and vector control programs.


Asunto(s)
Aedes/crecimiento & desarrollo , Fiebre Chikungunya/transmisión , Transmisión de Enfermedad Infecciosa , Ecosistema , Mosquitos Vectores/crecimiento & desarrollo , Animales , Femenino , Polinesia , Estudios Prospectivos , Medición de Riesgo , Encuestas y Cuestionarios
6.
PLoS Negl Trop Dis ; 14(5): e0007504, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32392222

RESUMEN

In South East Asia, dengue epidemics have increased in size and geographical distribution in recent years. We examined the spatiotemporal distribution and epidemiological characteristics of reported dengue cases in the predominantly rural state of Sabah, in Malaysian Borneo-an area where sylvatic and urban circulation of pathogens are known to intersect. Using a public health data set of routinely notified dengue cases in Sabah between 2010 and 2016, we described demographic and entomological risk factors, both before and after a 2014 change in the clinical case definition for the disease. Annual dengue incidence rates were spatially variable over the 7-year study period from 2010-2016 (state-wide mean annual incidence of 21 cases/100,000 people; range 5-42/100,000), but were highest in rural localities in the western districts of the state (Kuala Penyu, Nabawan, Tenom and Kota Marudu). Eastern districts exhibited lower overall dengue rates, although a high proportion of severe (haemorrhagic) dengue cases (44%) were focused in Sandakan and Tawau. Dengue incidence was highest for those aged between 10 and 29 years (24/100,000), and was slightly higher for males compared to females. Available vector surveillance data indicated that during large outbreaks in 2015 and 2016 the mosquito Aedes albopictus was more prevalent in both urban and rural households (House Index of 64%) than Ae. aegypti (15%). Demographic patterns remained unchanged both before and after the dengue case definition was changed; however, in the years following the change, reported case numbers increased substantially. Overall, these findings suggest that dengue outbreaks in Sabah are increasing in both urban and rural settings. Future studies to better understand the drivers of risk in specific age groups, genders and geographic locations, and to test the potential role of Ae. albopictus in transmission, may help target dengue prevention and control efforts.


Asunto(s)
Dengue/epidemiología , Adolescente , Adulto , Aedes/fisiología , Aedes/virología , Distribución por Edad , Animales , Niño , Preescolar , Dengue/mortalidad , Dengue/transmisión , Dengue/virología , Virus del Dengue/fisiología , Femenino , Humanos , Incidencia , Lactante , Malasia/epidemiología , Masculino , Persona de Mediana Edad , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Adulto Joven
7.
Parasit Vectors ; 13(1): 188, 2020 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-32276649

RESUMEN

BACKGROUND: Vector-borne diseases are a major public health concern and cause significant morbidity and mortality. Zika virus (ZIKV) is the etiologic agent of a massive outbreak in the Americas that originated in Brazil in 2015 and shows a strong association with congenital ZIKV syndrome in newborns. Cache Valley virus (CVV) is a bunyavirus that causes mild to severe illness in humans and ruminants. In this study, we investigated the vector competence of Virginia mosquitoes for ZIKV and CVV to explore their abilities to contribute to potential outbreaks. METHODS: To determine vector competence, mosquitoes were fed a blood meal comprised of defibrinated sheep blood and virus. The presence of midgut or salivary gland barriers to ZIKV infection were determined by intrathoracic inoculation vs oral infection. After 14-days post-exposure, individual mosquitoes were separated into bodies, legs and wings, and saliva expectorant. Virus presence was detected by plaque assay to determine midgut infection, dissemination, and transmission rates. RESULTS: Transmission rates for Ae. albopictus orally infected (24%) and intrathoracically inoculated (63%) with ZIKV was similar to Ae. aegypti (48% and 71%, respectively). Transmission rates of ZIKV in Ae. japonicus were low, and showed evidence of a midgut infection barrier demonstrated by low midgut infection and dissemination rates from oral infection (3%), but increased transmission rates after intrathoracic inoculation (19%). Aedes triseriatus was unable to transmit ZIKV following oral infection or intrathoracic inoculation. CVV transmission was dose-dependent where mosquitoes fed high titer (ht) virus blood meals developed higher rates of midgut infection, dissemination, and transmission compared to low titer (lt) virus blood meals. CVV was detected in the saliva of Ae. albopictus (ht: 68%, lt: 24%), Ae. triseriatus (ht: 52%, lt: 7%), Ae. japonicus (ht: 22%, lt: 0%) and Ae. aegypti (ht: 10%; lt: 7%). Culex pipiens and Cx. restuans were not competent for ZIKV or CVV. CONCLUSIONS: This laboratory transmission study provided further understanding of potential ZIKV and CVV transmission cycles with Aedes mosquitoes from Virginia. The ability for these mosquitoes to transmit ZIKV and CVV make them a public health concern and suggest targeted control programs by mosquito and vector abatement districts.


Asunto(s)
Virus Bunyamwera/aislamiento & purificación , Mosquitos Vectores/virología , Virus Zika/aislamiento & purificación , Aedes/virología , Animales , Bioensayo , Sangre/virología , Infecciones por Bunyaviridae/transmisión , Culex/virología , Vectores de Enfermedades , Humanos , Intestinos/virología , Saliva/virología , Estados Unidos , Carga Viral , Virginia , Infección por el Virus Zika/transmisión
8.
Parasit Vectors ; 13(1): 197, 2020 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-32299496

RESUMEN

BACKGROUND: Larval indices such as the house index (HI), Breteau index (BI) and container index (CI) are widely used to interpret arbovirus vector density in surveillance programmes. However, the use of such data as an alarm signal is rarely considered consciously when planning programmes. The present study aims to investigate the spatial distribution pattern of the infestation of Aedes aegypti, considering the data available in the Ae. aegypti Infestation Index Rapid Survey (LIRAa) for the city of Campina Grande, Paraíba State in Brazil. METHODS: The global and local Moran's indices were used in spatial analysis to measure the effects of spatial dependencies between neighbourhoods, using secondary data related to HI and BI gathered from surveillance service. RESULTS: Our analysis shows that there is a predominance of high rates of mosquito infestation, placing Campina Grande at a near-constant risk of arbovirus outbreaks and epidemics. A highly significant Moran's index value (P < 0.001) was observed, indicating a positive spatial dependency between the neighbourhoods in Campina Grande. Using the Moran mapping and LISA mapping, the autocorrelation patterns of Ae. aegypti infestation rates among neighbourhoods have revealed hotpots that should be considered a priority to preventive actions of the entomological surveillance services. Predominance of high infestation rates and clearer relationships of these between neighbourhoods were observed between the months of May and July, the period with the highest rainfall in the city. CONCLUSIONS: This analysis is an innovative strategy capable of providing detailed information on infestation locations to the relevant public health authorities, which will enable a more efficient allocation of resources, particularly for arbovirus prevention.


Asunto(s)
Aedes , Control de Mosquitos , Mosquitos Vectores , Densidad de Población , Análisis Espacial , Aedes/fisiología , Aedes/virología , Animales , Infecciones por Arbovirus/prevención & control , Infecciones por Arbovirus/transmisión , Brasil/epidemiología , Ecosistema , Modelos Teóricos , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Estaciones del Año , Urbanización
9.
Viruses ; 12(4)2020 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-32316394

RESUMEN

Mosquito-borne viruses are emerging or re-emerging globally, afflicting millions of people around the world. Aedes aegypti, the yellow fever mosquito, is the principal vector of dengue, Zika, and chikungunya viruses, and has well-established populations across tropical and subtropical urban areas of the Americas, including the southern United States. While intense arboviral epidemics have occurred in Mexico and further south in the Americas, local transmission in the United States has been minimal. Here, we study Ae. aegypti and Culex quinquefasciatus host feeding patterns and vertebrate host communities in residential environments of South Texas to identify host-utilization relative to availability. Only 31% of Ae. aegypti blood meals were derived from humans, while 50% were from dogs and 19% from other wild and domestic animals. In Cx. quinquefasciatus, 67% of blood meals were derived from chicken, 22% came from dogs, 9% from various wild avian species, and 2% from other mammals including one human, one cat, and one pig. We developed a model for the reproductive number, R0, for Zika virus (ZIKV) in South Texas relative to northern Mexico using human disease data from Tamaulipas, Mexico. We show that ZIKV R0 in South Texas communities could be greater than one if the risk of human exposure to Ae. aegypti bites in these communities is at least 60% that of Northern Mexico communities. The high utilization of non-human vertebrates and low risk of human exposure in South Texas diminishes the outbreak potential for human-amplified urban arboviruses transmitted by Ae. aegypti.

10.
PLoS Negl Trop Dis ; 14(4): e0007518, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32287269

RESUMEN

Newly emerging or re-emerging arthropod-borne viruses (arboviruses) are important causes of human morbidity and mortality worldwide. Arboviruses such as Dengue (DENV), Zika (ZIKV), Chikungunya (CHIKV), and West Nile virus (WNV) have undergone extensive geographic expansion in the tropical and sub-tropical regions of the world. In the Americas the main vectors of DENV, ZIKV, and CHIKV are mosquito species adapted to urban environments, namely Aedes aegypti and Aedes albopictus, whereas the main vector of WNV is Culex quinquefasciatus. Given the widespread distribution in the Americas and high permissiveness to arbovirus infection, these mosquito species may play a key role in the epidemiology of other arboviruses normally associated with sylvatic vectors. Here, we test this hypothesis by determining the vector competence of Ae. aegypti, Ae. albopictus, and Cx. quinquefasciatus to Mayaro (MAYV) virus, a sylvatic arbovirus transmitted mainly by Haemagogus janthinomys that has been causing an increasing number of outbreaks in South America, namely in Brazil. Using field mosquitoes from Brazil, female mosquitoes were experimentally infected, and their competence for infection and transmission rates of MAYV was evaluated. We found consistent infection rate for MAYV in Ae. aegypti (57.5%) and Ae. albopictus (61.6%), whereas very low rates were obtained for Cx. quinquefasciatus (2.5%). Concordantly, we observed high potential transmission ability in Ae. aegypti and Ae. albopictus (69.5% and 71.1% respectively), in contrast to Cx. quinquefasciatus, which could not transmit the MAYV. Notably, we found that very low quantities of virus present in the saliva (undetectable by RT-qPCR) were sufficiently virulent to guarantee transmission. Although Ae. aegypti and Ae. albopictus mosquitoes are not the main vectors for MAYV, our studies suggest that these mosquitoes could play a significant role in the transmission of this arbovirus, since both species showed significant vector competence for MAYV (Genotype D), under laboratory conditions.


Asunto(s)
Aedes/virología , Infecciones por Alphavirus/virología , Alphavirus/aislamiento & purificación , Culex/virología , Transmisión de Enfermedad Infecciosa , Alphavirus/genética , Alphavirus/crecimiento & desarrollo , Infecciones por Alphavirus/transmisión , Animales , Brasil , Femenino , Reacción en Cadena en Tiempo Real de la Polimerasa , Saliva/virología , Carga Viral
11.
PLoS One ; 15(4): e0230910, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32236146

RESUMEN

Several sites, Z-7L, Z-5 and Z-14, in Sibu district, Sarawak, Malaysia, experienced intense dengue transmission in 2014 that continued into 2015. A pilot study with Bacillus thuringiensis israelensis (Bti) to control Aedes aegypti (L.) and Ae. albopictus (Skuse) was evaluated in Z-7L, a densely populated site of 12 ha. Bti treatments were conducted weekly from epidemiology week (EW) 24/2015 for 4 weeks, followed by fortnight treatments for 2 months, in addition to the routine control activities. Bti was directly introduced into potable containers and the outdoor artificial and natural containers were treated via a wide area spray application method using a backpack mister. Aedes indices significantly reduced during the treatment and post treatment phases, compared to the control site, Z-5 (p<0.05). A 51 fold reduction in the incidence rate per 100,000 population (IR) was observed, with one case in 25 weeks (EW 29-52). In Z-5 and Z-14, control sites, a 6 fold reduction in the IR was observed from EW 29-52. However, almost every week there were dengue cases in Z-14 and until EW 44 in Z-5. In 2016, dengue cases resurfaced in Z-7L from EW 4. Intensive routine control activities were conducted, but the IR continued to escalate. The wide area Bti spray misting of the outdoor containers was then included from EW 27 on fortnight intervals. A 6 fold reduction in IR was observed in the Bti treatment phase (EW 32-52) with no successive weekly cases after EW 37. However, in the control sites, there were dengue cases throughout the year from EW 1-52, particularly in Z-14. We feel that the wide area Bti spray application method is an integral component in the control program, in conjunction with other control measures carried out, to suppress the vector population in outdoor cryptic containers and to interrupt the disease transmission.


Asunto(s)
Bacillus thuringiensis , Agentes de Control Biológico , Dengue , Mosquitos Vectores , Aedes/microbiología , Aedes/virología , Animales , Dengue/epidemiología , Dengue/transmisión , Reservorios de Enfermedades/virología , Vectores de Enfermedades , Insecticidas , Larva/microbiología , Larva/virología , Malasia/epidemiología , Control de Mosquitos/métodos , Mosquitos Vectores/microbiología , Mosquitos Vectores/virología , Proyectos Piloto , Prevalencia
12.
PLoS Negl Trop Dis ; 14(4): e0008217, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32282830

RESUMEN

BACKGROUND: The Asian bush mosquito Aedes japonicus is invading Europe and was first discovered in Lelystad, the Netherlands in 2013, where it has established a permanent population. In this study, we investigated the vector competence of Ae. japonicus from the Netherlands for the emerging Zika virus (ZIKV) and zoonotic Usutu virus (USUV). ZIKV causes severe congenital microcephaly and Guillain-Barré syndrome in humans. USUV is closely related to West Nile virus, has recently spread throughout Europe and is causing mass mortality of birds. USUV infection in humans can result in clinical manifestations ranging from mild disease to severe neurological impairments. METHODOLOGY/PRINCIPAL FINDINGS: In our study, field-collected Ae. japonicus females received an infectious blood meal with ZIKV or USUV by droplet feeding. After 14 days at 28°C, 3% of the ZIKV-blood fed mosquitoes and 13% of the USUV-blood fed mosquitoes showed virus-positive saliva, indicating that Ae. japonicus can transmit both viruses. To investigate the effect of the mosquito midgut barrier on virus transmission, female mosquitoes were intrathoracically injected with ZIKV or USUV. Of the injected mosquitoes, 96% (ZIKV) and 88% (USUV) showed virus-positive saliva after 14 days at 28°C. This indicates that ZIKV and USUV can efficiently replicate in Ae. japonicus but that a strong midgut barrier is normally restricting virus dissemination. Small RNA deep sequencing of orally infected mosquitoes confirmed active replication of ZIKV and USUV, as demonstrated by potent small interfering RNA responses against both viruses. Additionally, de novo small RNA assembly revealed the presence of a novel narnavirus in Ae. japonicus. CONCLUSIONS/SIGNIFICANCE: Given that Ae. japonicus can experimentally transmit arthropod-borne viruses (arboviruses) like ZIKV and USUV and is currently expanding its territories, we should consider this mosquito as a potential vector for arboviral diseases in Europe.


Asunto(s)
Aedes/virología , Infecciones por Flavivirus/transmisión , Mosquitos Vectores/virología , Infección por el Virus Zika/transmisión , Animales , Femenino , Flavivirus , Humanos , Microcefalia/virología , Países Bajos , Saliva/virología , Temperatura , Virus Zika
13.
PLoS Negl Trop Dis ; 14(4): e0008219, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32298261

RESUMEN

Aedes aegypti is the primary vector of dengue, chikungunya, Zika, and urban yellow fever. Insecticides are often the most effective tools to rapidly decrease the density of vector populations, especially during arbovirus disease outbreaks. However, the intense use of insecticides, particularly pyrethroids, has selected for resistant mosquito populations worldwide. Mutations in the voltage gated sodium channel (NaV) are among the principal mechanisms of resistance to pyrethroids and DDT, also known as "knockdown resistance," kdr. Here we report studies on the origin and dispersion of kdr haplotypes in samples of Ae. aegypti from its worldwide distribution. We amplified the IIS6 and IIIS6 NaV segments from pools of Ae. aegypti populations from 15 countries, in South and North America, Africa, Asia, Pacific, and Australia. The amplicons were barcoded and sequenced using NGS Ion Torrent. Output data were filtered and analyzed using the bioinformatic pipeline Seekdeep to determine frequencies of the IIS6 and IIIS6 haplotypes per population. Phylogenetic relationships among the haplotypes were used to infer whether the kdr mutations have a single or multiple origin. We found 26 and 18 haplotypes, respectively for the IIS6 and IIIS6 segments, among which were the known kdr mutations 989P, 1011M, 1016I and 1016G (IIS6), 1520I, and 1534C (IIIS6). The highest diversity of haplotypes was found in African samples. Kdr mutations 1011M and 1016I were found only in American and African populations, 989P + 1016G and 1520I + 1534C in Asia, while 1534C was present in samples from all continents, except Australia. Based primarily on the intron sequence, IIS6 haplotypes were subdivided into two well-defined clades (A and B). Subsequent phasing of the IIS6 + IIIS6 haplotypes indicates two distinct origins for the 1534C kdr mutation. These results provide evidence of kdr mutations arising de novo at specific locations within the Ae. aegypti geographic distribution. In addition, our results suggest that the 1534C kdr mutation had at least two independent origins. We can thus conclude that insecticide selection pressure with DDT and more recently with pyrethroids is selecting for independent convergent mutations in NaV.


Asunto(s)
Aedes/efectos de los fármacos , Aedes/genética , Genes de Insecto , Resistencia a los Insecticidas/genética , Mutación , Aedes/virología , África , Alelos , Animales , Asia , Australia , Fiebre Chikungunya/prevención & control , Fiebre Chikungunya/transmisión , ADN/genética , Dengue/prevención & control , Dengue/transmisión , Frecuencia de los Genes , Genotipo , Insecticidas , Mosquitos Vectores/genética , Mosquitos Vectores/virología , América del Norte , Piretrinas , Fiebre Amarilla/prevención & control , Fiebre Amarilla/transmisión , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/transmisión
14.
PLoS Negl Trop Dis ; 14(4): e0008209, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32310960

RESUMEN

Dengue, a vector-borne disease spread by Aedes mosquitoes, is a global threat. In the absence of an efficacious dengue vaccine, vector control is the key intervention tool in Singapore. A good understanding of vector habitats is essential to formulate operational strategies. We examined the distribution, long-term trend and seasonality of Aedes data collected during regulatory inspections in residences and public areas from 2008 to 2017. We also studied the seasonality of climate factors to understand their influence on the detection of Aedes-positive containers. The most frequently reported Aedes-positive containers were domestic containers, drains, discarded receptacles, ornamental containers, flower pot plates/trays, plants, gully traps, canvas/plastic sheet, bins, ground puddle, inspection chambers and roof tops/gutters. We found more Ae. aegypti and Ae. albopictus-positive containers per inspection in residences and public areas, respectively. The seasonality of Ae. aegypti-positive containers in residences and public areas coincided with that of mean temperature. However, the seasonality of Ae. albopictus-positive containers lagged by one month compared to that of mean temperature. Our study demonstrates the seasonal fluctuations of Aedes-positive containers in an urban environment. Understanding the distribution and seasonality of Aedes breeding helps to facilitate resource planning and community awareness to moderate dengue transmission.


Asunto(s)
Aedes/crecimiento & desarrollo , Aedes/virología , Distribución Animal , Ambiente , Estaciones del Año , Aedes/clasificación , Animales , Dengue/transmisión , Virus del Dengue/aislamiento & purificación , Virus del Dengue/fisiología , Vivienda , Larva/virología , Mosquitos Vectores/virología , Pupa/virología , Singapur
15.
Am J Trop Med Hyg ; 102(5): 964-970, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32228777

RESUMEN

Two confirmed human cases of Zika virus (ZIKV) were reported in the district of Miri, Sarawak, in 2016. Following that, a mosquito-based ZIKV surveillance study was conducted within 200-m radius from the case houses. Mosquito surveillance was conducted using five different methods, that is, biogents sentinel mosquito (BG) sentinel trap, modified sticky ovitrap, resting catch, larval surveillance, and conventional ovitrap. A total of 527 and 390 mosquito samples were obtained from the case houses in two localities, namely, Kampung Lopeng and Taman Shang Ri La, Miri, Sarawak, respectively. All mosquitoes collected were identified, which consisted of 11 species. Aedes albopictus, both the adult and larval stages, was the dominant species. Resting catch method obtained the highest number of adult mosquitoes (67%), whereas ovitrap showed the highest catch for larval mosquitoes (84%). Zika virus was detected in both adults and larvae of Ae. albopictus together with adults of Culex gelidus, and Culex quinquefasciatus using the real-time reverse transcriptase polymerase chain reaction (PCR) technique. It was noteworthy that Ae. albopictus positive with ZIKV were caught and obtained from four types of collection method. By contrast, Cx. gelidus and Culex quinquefasciatus adults collected from sticky ovitraps were also found positive with ZIKV. This study reveals vital information regarding the potential vectors of ZIKV and the possibility of transovarian transmission of the virus in Malaysia. These findings will be essentials for vector control program managers to devise preparedness and contingency plans of prevention and control of the arboviral disease.


Asunto(s)
Culicidae/virología , Mosquitos Vectores/virología , Infección por el Virus Zika/epidemiología , Aedes/virología , Animales , Culex/virología , Femenino , Humanos , Malasia/epidemiología , Masculino , Vigilancia de la Población , Reacción en Cadena en Tiempo Real de la Polimerasa , Infección por el Virus Zika/etiología , Infección por el Virus Zika/transmisión
16.
Rev Soc Bras Med Trop ; 53: e20190504, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32267458

RESUMEN

INTRODUCTION: The study of the landscape ecology, biological microhabitat, and epidemiological implications for the distribution of the main vectors Aedes aegypti and Aedes albopictus contribute to the prevention and control actions regarding the diseases they transmit. METHODS: This study sought to assess data on positive properties of the vector control program activities from 1998 to 2010. An entomological survey was also carried out on a sample of buildings collecting larvae and pupae from containers between October and April (spring / summer) from 2002 to 2005. We assessed the physico-chemical data of the water in 20% of positive containers. The vegetation and urbanization were assessed with the aid of satellite images and microenvironments were classified as urbanized, woods, and shrubs. The data were analyzed using statistical and geoprocessing software. RESULTS: Ae. aegypti and Ae. albopictus colonized all types of microhabitats and microenvironments, predominantly in the urbanized area, in isolation and in coexistence. The microhabitat of Ae. aegypti showed a temperature gradient greater than that of Ae. albopictus, and there was an association with urbanized areas for the first species and wooded areas for the last species. CONCLUSIONS: Landscape ecology and intra-urban differences favor different microclimates, which contribute to the coexistence of species in the urban environment in an area close to the forest, raising the risk of other arbovirus infections in urban areas. The ecological niche should be considered for Ae. albopictus. Entomological and virologic monitoring are suggested as arbovirus surveillance actions in urban infested centers near preserved forests.


Asunto(s)
Aedes/fisiología , Ecosistema , Mosquitos Vectores/fisiología , Aedes/clasificación , Distribución Animal , Animales , Infecciones por Arbovirus/transmisión , Brasil , Mosquitos Vectores/clasificación , Densidad de Población , Estaciones del Año , Análisis Espacial , Población Urbana
17.
PLoS One ; 15(4): e0232192, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32343725

RESUMEN

The introduction of exotic disease vectors into a new habitat can drastically change the local epidemiological situation. During 2012-2015, larvae and an adult of the yellow-fever mosquito, Aedes aegypti, were captured alive at two international airports serving the Greater Tokyo Area, Japan. Because this species does not naturally distribute in this country, those mosquitoes were considered to be introduced from overseas via air-transportation. To infer the places of origin of those mosquitoes, we genotyped the 12 microsatellite loci for which the most comprehensive population genetic reference is currently available. Although clustering by Bayesian and multivariate methods both suggested that all those mosquitoes captured at the airports in Japan belonged to the Asia/Pacific populations, they were not clustered into a single cluster. Moreover, there was variation in mitochondrial cytochrome oxidase I gene (CoxI) haplotypes among mosquitoes collected in different incidents of discovery which indicated the existence of multiple maternal origins. We conclude there is little evidence to support the overwintering of Ae. aegypti at the airports; nevertheless, special attention is still needed to prevent the invasion of this prominent arbovirus vector.


Asunto(s)
Aedes/genética , Aeropuertos , Mosquitos Vectores/genética , Aedes/clasificación , Aedes/virología , Animales , Infecciones por Arbovirus/transmisión , Infecciones por Arbovirus/virología , Arbovirus/aislamiento & purificación , Arbovirus/patogenicidad , Teorema de Bayes , Ecosistema , Complejo IV de Transporte de Electrones/genética , Genes de Insecto , Genes Mitocondriales , Variación Genética , Genética de Población , Genotipo , Haplotipos , Humanos , Proteínas de Insectos/genética , Repeticiones de Microsatélite , Mosquitos Vectores/clasificación , Mosquitos Vectores/virología , Tokio
18.
PLoS Comput Biol ; 16(4): e1007743, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-32310958

RESUMEN

Recent years have seen rising incidence of dengue and large outbreaks of Zika and chikungunya, which are all caused by viruses transmitted by Aedes aegypti mosquitoes. In most settings, the primary intervention against Aedes-transmitted viruses is vector control, such as indoor, ultra-low volume (ULV) spraying. Targeted indoor residual spraying (TIRS) has the potential to more effectively impact Aedes-borne diseases, but its implementation requires careful planning and evaluation. The optimal time to deploy these interventions and their relative epidemiological effects are, however, not well understood. We used an agent-based model of dengue virus transmission calibrated to data from Iquitos, Peru to assess the epidemiological effects of these interventions under differing strategies for deploying them. Specifically, we compared strategies where spray application was initiated when incidence rose above a threshold based on incidence in recent years to strategies where spraying occurred at the same time(s) each year. In the absence of spraying, the model predicted 361,000 infections [inter-quartile range (IQR): 347,000-383,000] in the period 2000-2010. The ULV strategy with the fewest median infections was spraying twice yearly, in March and October, which led to a median of 172,000 infections [IQR: 158,000-183,000], a 52% reduction from baseline. Compared to spraying once yearly in September, the best threshold-based strategy utilizing ULV had fewer median infections (254,000 vs. 261,000), but required more spraying (351 vs. 274 days). For TIRS, the best strategy was threshold-based, which led to the fewest infections of all strategies tested (9,900; [IQR: 8,720-11,400], a 94% reduction), and required fewer days spraying than the equivalent ULV strategy (280). Although spraying twice each year is likely to avert the most infections, our results indicate that a threshold-based strategy can become an alternative to better balance the translation of spraying effort into impact, particularly if used with a residual insecticide.


Asunto(s)
Biología Computacional/métodos , Dengue/prevención & control , Control de Mosquitos/métodos , Aedes/fisiología , Animales , Simulación por Computador , Dengue/epidemiología , Dengue/transmisión , Brotes de Enfermedades , Humanos , Incidencia , Insecticidas , Modelos Teóricos , Mosquitos Vectores , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/transmisión
19.
Epidemiol Infect ; 148: e72, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32234110

RESUMEN

From 1971 to 2012, in New York State, years with human Eastern equine encephalitis (EEE) were more strongly associated with the presence of Aedes canadensis, Coquillettidia perturbans and Culiseta melanura mosquitoes infected with the EEE virus (Fisher's exact test, one-sided P = 0.005, 0.03, 0.03) than with Culiseta morsitans, Aedes vexans, Culex pipiens-restuans, Anopheles quadrimaculatus or Anopheles punctipennis (P = 0.05, 0.40, 0.33, 1.00, 1.00). The estimated relative risk of a case in a year in which the virus was detected vs. not detected was 14.67 for Ae. canadensis, 6.38 for Cq. perturbans and 5.50 for Cs. morsitans. In all 5 years with a case, Cs. melanura with the virus was detected. In no year was there a case in the absence of Cs. melanura with the virus. There were 18 years with no case in the presence of Cs. melanura with the virus. Such observations may identify the time of increased risk, and when the methods may be used to prevent or reduce exposure to vector mosquito species in this geographic region.


Asunto(s)
Culicidae/virología , Virus de la Encefalitis Equina del Este , Encefalomielitis Equina Oriental , Mosquitos Vectores/virología , Aedes/virología , Animales , Encefalomielitis Equina Oriental/epidemiología , Encefalomielitis Equina Oriental/transmisión , Encefalomielitis Equina Oriental/virología , Humanos , New York , Análisis Espacio-Temporal
20.
PLoS Negl Trop Dis ; 14(3): e0008163, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32203510

RESUMEN

Zika virus (ZIKV) is a Flavivirus (Flaviviridae) transmitted to humans mainly by the bite of an infected Aedes mosquitoes. Aedes aegypti is the primary epidemic vector of ZIKV and Ae. albopictus, the secondary one. However, the epidemiological role of both Aedes species in Central Africa where Ae. albopictus was recently introduced is poorly characterized. Field-collected strains of Ae. aegypti and Ae. albopictus from different ecological settings in Central Africa were experimentally infected with a ZIKV strain isolated in West Africa. Mosquitoes were analysed at 14- and 21-days post-exposure. Both Ae. aegypti and Ae. albopictus were able to transmit ZIKV but with higher overall transmission efficiency for Ae. aegypti (57.9%) compared to Ae. albopictus (41.5%). In addition, disseminated infection and transmission rates for both Ae. aegypti and Ae. albopictus varied significantly according to the location where they were sampled from. We conclude that both Ae. aegypti and Ae. albopictus are able to transmit ZIKV and may intervene as active Zika vectors in Central Africa. These findings could contribute to a better understanding of the epidemiological transmission of ZIKV in Central Africa and develop suitable strategy to prevent major ZIKV outbreaks in this region.


Asunto(s)
Aedes/virología , Mosquitos Vectores/virología , Infección por el Virus Zika/virología , Virus Zika/aislamiento & purificación , Aedes/clasificación , África Central , Animales , Susceptibilidad a Enfermedades , Femenino , Mapeo Geográfico , Mosquitos Vectores/clasificación , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/transmisión
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA