RESUMEN
The Atlantic Forest Biome (AFB) creates an ideal environment for the proliferation of vector mosquitoes, such as Haemagogus and Sabethes species, which transmit the Yellow Fever virus (YFV) to both human and non-human primates (NHP) (particularly Alouatta sp. and Callithrix sp.). From 2016 to 2020, 748 fatal cases of YF in humans and 1,763 in NHPs were reported in this biome, following several years free from the disease. This underscores the imminent risk posed by the YFV. In this study, we examined the spatiotemporal distribution patterns of YF cases in both NHPs and humans across the entire AFB during the outbreak period, using a generalized linear mixed regression model (GLMM) at the municipal level. Our analysis examined factors associated with the spread of YFV, including environmental characteristics, climate conditions, human vaccination coverage, and the presence of two additional YFV-affected NHP species. The occurrence of epizootics has been directly associated with natural forest formations and the presence of species within the Callithrix genus. Additionally, epizootics have been shown to be directly associated with human prevalence. Furthermore, human prevalence showed an inverse correlation with urban areas, temporary croplands, and savannah and grassland areas. Further analyses using Moran's Index to incorporate the neighborhoods of municipalities with cases in each studied host revealed additional variables, such as altitude, which showed a positive correlation. Additionally, the occurrence of the disease in both hosts exhibited a spatio-temporal distribution pattern. To effectively mitigate the spread of the virus, it is necessary to proactively expand vaccination coverage, refine NHP surveillance strategies, and enhance entomological surveillance in both natural and modified environments.
Asunto(s)
Bosques , Mosquitos Vectores , Fiebre Amarilla , Virus de la Fiebre Amarilla , Fiebre Amarilla/epidemiología , Fiebre Amarilla/transmisión , Animales , Humanos , Brasil/epidemiología , Mosquitos Vectores/virología , Clima , Brotes de Enfermedades , EcosistemaRESUMEN
Aedes mosquito-borne viruses (ABVs) place a substantial strain on public health resources in the Americas. Vector control of Aedes mosquitoes is an important public health strategy to decrease or prevent spread of ABVs. The ongoing Targeted Indoor Residual Spraying (TIRS) trial is an NIH-sponsored clinical trial to study the efficacy of a novel, proactive vector control technique to prevent dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) infections in the endemic city of Merida, Yucatan, Mexico. The primary outcome of the trial is laboratory-confirmed ABV infections in neighborhood clusters. Despite the difficulties caused by the COVID-19 pandemic, by early 2021 the TIRS trial completed enrollment of 4,792 children aged 2-15 years in 50 neighborhood clusters which were allocated to control or intervention arms via a covariate-constrained randomization algorithm. Here, we describe the makeup and ABV seroprevalence of participants and mosquito population characteristics in both arms before TIRS administration. Baseline surveys showed similar distribution of age, sex, and socio-economic factors between the arms. Serum samples from 1,399 children were tested by commercially available ELISAs for presence of anti-ABV antibodies. We found that 45.1% of children were seropositive for one or more flaviviruses and 24.0% were seropositive for CHIKV. Of the flavivirus-positive participants, most were positive for ZIKV-neutralizing antibodies by focus reduction neutralization testing which indicated a higher proportion of participants with previous ZIKV than DENV infections within the cohort. Both study arms had statistically similar seroprevalence for all viruses tested, similar socio-demographic compositions, similar levels of Ae. aegypti infestation, and similar observed mosquito susceptibility to insecticides. These findings describe a population with a high rate of previous exposure to ZIKV and lower titers of neutralizing antibodies against DENV serotypes, suggesting susceptibility to future outbreaks of flaviviruses is possible, but proactive vector control may mitigate these risks.
Asunto(s)
Aedes , Dengue , Insecticidas , Control de Mosquitos , Mosquitos Vectores , Humanos , Niño , Aedes/virología , Animales , México/epidemiología , Adolescente , Preescolar , Femenino , Control de Mosquitos/métodos , Masculino , Mosquitos Vectores/virología , Dengue/epidemiología , Dengue/prevención & control , Dengue/virología , Estudios Seroepidemiológicos , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/prevención & control , Virus Zika/inmunología , Virus Zika/aislamiento & purificación , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/prevención & control , Virus del Dengue/inmunología , Virus del Dengue/aislamiento & purificación , Virus Chikungunya/inmunologíaRESUMEN
Advances in diagnostic techniques coupled with ongoing environmental changes have resulted in intensified surveillance and monitoring of arbovirus circulation in the Amazon. This increased effort has resulted in increased detection of insect-specific viruses among hematophagous arthropods collected in the field. This study aimed to document the first isolation of Agua Salud alphavirus in mosquitoes collected within the Brazilian Amazon. Arthropods belonging to the family Culicidae were collected within a forest fragment located in the Environmental Protection Area of the metropolitan region of Belem. Subsequently, these specimens were meticulously identified to the species level. Afterward, the collected batches were macerated, and the resulting supernatant was then inoculated into C6/36 and Vero cell cultures to facilitate viral isolation. The presence of arboviruses within the inoculated cell cultures was determined through indirect immunofluorescence analysis. Furthermore, positive supernatant samples underwent nucleotide sequencing to precisely identify the viral strains present. Notably, a batch containing Culex (Melanoconion) mosquitoes was identified to be positive for the genus Alphavirus via indirect immunofluorescence. This study is the first report on insect-specific alphavirus isolation in Brazil and the first-ever description of Agua Salud alphavirus isolation within Amazon Forest remnants.
Asunto(s)
Alphavirus , Culex , Animales , Alphavirus/aislamiento & purificación , Alphavirus/genética , Alphavirus/clasificación , Brasil , Células Vero , Chlorocebus aethiops , Culex/virología , Mosquitos Vectores/virología , Filogenia , Arbovirus/aislamiento & purificación , Arbovirus/genética , Arbovirus/clasificaciónRESUMEN
BACKGROUND: Dengue is a vector-borne viral infection caused by the dengue virus transmitted to humans primarily by Aedes aegypti. The year 2024 has been a historic year for dengue in Brazil, with the highest number of probable cases ever registered. Herein, we analyze the temporal trend and spatio-temporal dynamics of dengue cases in Brazil during the first nine epidemiological weeks (EW) of 2024. METHODS: This is an ecological study, including all probable cases of dengue in Brazil during the period, carried out in two steps: time series analysis to assess the temporal trend and spatial analysis to identify high-risk clusters. RESULTS: 1,345,801 probable cases of dengue were reported. The regions with the highest increasing trend were the Northeast with an average epidemiologic week percent change (AEPC) of 52.4 (95% CI: 45.5-59.7; p < 0.001) and the South with 35.9 (95% CI: 27.7-44.5; p < 0.001). There was a statistically significant increasing trend in all states, except Acre (AEPC = -4.1; 95% CI: -16.3-10; p = 0.55), Amapá (AEPC = 1.3; 95% CI: -16.2-22.3; p = 0.9) and Espírito Santo (AEPC = 8.9; 95% CI: -15.7-40.6; p = 0.5). The retrospective space-time analysis showed a cluster within the Northeast, Central-West and Southeast regions, with a radius of 515.3 km, in which 1,267 municipalities and 525,324 of the cases were concentrated (RR = 6.3; p < 0.001). Regarding the spatial variation of the temporal trend, 21 risk areas were found, all of them located in Southeast or Central-West states. The area with the highest relative risk was Minas Gerais state, where 5,748 cases were concentrated (RR = 8.1; p < 0.001). Finally, a purely spatial analysis revealed 25 clusters, the one with the highest relative risk being composed of two municipalities in Acre (RR = 6.9; p < 0.001). CONCLUSIONS: We described a detailed temporal-spatial analysis of dengue cases in the first EWs of 2024 in Brazil, which were mainly concentrated in the Southeast and Central-West regions. Overall, it is recommended that governments adopt public policies to control the the vector population in high-risk areas, as well as to prevent the spread of dengue fever to other areas of Brazil.
Asunto(s)
Aedes , Dengue , Epidemias , Análisis Espacio-Temporal , Brasil/epidemiología , Dengue/epidemiología , Dengue/transmisión , Humanos , Epidemias/estadística & datos numéricos , Aedes/virología , Animales , Toma de Decisiones , Mosquitos Vectores/virología , Virus del DengueRESUMEN
The genus Flavivirus (Family: Flaviviridae) comprises arboviruses with the capacity to infect humans and animals. It also integrates insect-specific viruses. This study aimed to identify Flavivirus in mosquitoes captured in 17 municipalities in Yucatan State, Mexico. The mosquitoes were caught in households from November 2021 to May 2022. A total of 4,321 adult mosquitoes from five species were caught. The most abundant were Culex quinquefasciatus (n = 3,563) and Aedes aegypti (n = 734). For molecular investigations, 600 female mosquitoes were split into groups of 10, mostly for species and site location. Reverse transcriptase polymerase chain reaction (RT-PCR) amplified a region of the NS5 gene to find the Flavivirus ribonucleic acids (RNA). A total of 24 pools that were positive for Flavivirus were detected in Ae. aegypti specimens and subsequently subjected to sequencing using the Sanger method. A total of 12 sequences matched the established quality criteria and were subsequently employed for sequence homology analysis. We found that one sequence corresponded to the Zika virus (ZIKV), and 11 sequences had sequence similarity with Phlebotomus-associated flavivirus (PAFV), an insect-specific virus (ISF). In conclusion, we found ZIKV in the Merida municipality, Yucatan State, which suggests that the virus is silently circulating. Phlebotomus-associated flavivirus is distributed in five municipalities in Yucatan State, Mexico. Future studies could focus on isolating this virus and studying its biological role within Ae. aegypti.
Asunto(s)
Culicidae , Flavivirus , Mosquitos Vectores , Animales , México , Flavivirus/genética , Flavivirus/aislamiento & purificación , Flavivirus/clasificación , Mosquitos Vectores/virología , Femenino , Culicidae/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , ARN Viral/genética , ARN Viral/análisis , Culex/virologíaRESUMEN
Studies on animal virome have mainly concentrated on chordates and medically significant invertebrates, often overlooking sylvatic mosquitoes, constituting a major part of mosquito species diversity. Despite their potential role in arbovirus transmission, the viromes of sylvatic mosquitoes remain largely unexplored. These mosquitoes may also harbor insect-specific viruses (ISVs), affecting arboviral transmission dynamics. The Cerrado biome, known for rapid deforestation and its status as a biodiversity hotspot, offers an ideal setting for investigating mosquito viromes due to potential zoonotic spillover risks from land use changes. This study aimed to characterize the viromes of sylvatic mosquitoes collected from various locations within Minas Gerais state, Brazil. The total RNA was extracted from mosquito pools of Psorophora albipes, Sabethes albiprivus, Sa. chloropterus, Psorophora ferox, and Coquillettidia venezuelensis species, followed by high-throughput sequencing (HTS). Bioinformatic analysis included quality control, contig assembly, and viral detection. Sequencing data analysis revealed 11 near-complete viral genomes (new viruses are indicated with asterisks) across seven viral families and one unassigned genus. These included: Xinmoviridae (Ferox mosquito mononega-like virus* and Albipes mosquito Gordis-like virus*), Phasmaviridae (Sabethes albiprivus phasmavirus*), Lispiviridae (Pedras lispivirus variant MG), Iflaviridae (Sabethes albiprivus iflavivirus*), Virgaviridae (Buriti virga-like virus variant MG and Sabethes albiprivus virgavirus 1*), Flaviviridae (Psorophora ferox flavivirus*), Mesoniviridae (Alphamesonivirus cavallyense variant MG), and the genus Negevirus (Biggie virus variant MG virus and Coquillettidia venezuelensis negevirus*). Moreover, the presence of ISVs and potential novel arboviruses underscores the need for ongoing surveillance and control strategies to mitigate the risk of emerging infectious diseases.
Asunto(s)
Infecciones por Arbovirus , Arbovirus , Culicidae , Mosquitos Vectores , Filogenia , Viroma , Animales , Brasil , Arbovirus/genética , Arbovirus/clasificación , Arbovirus/aislamiento & purificación , Viroma/genética , Culicidae/virología , Infecciones por Arbovirus/transmisión , Infecciones por Arbovirus/virología , Mosquitos Vectores/virología , Genoma Viral , Secuenciación de Nucleótidos de Alto Rendimiento , Virus de Insectos/genética , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificaciónRESUMEN
According to the IPCC, by the year 2100, rises in global temperature could reach up to 5 °C above current averages. On a planet-wide scale, this is one of the effects of climate changes that could have repercussions on the biological cycle of Aedes aegypti, the main arbovirus vector in urban environments and a transmitter of the arboviruses that cause dengue, Zika, chikungunya and urban yellow fever. The objective of this study was to evaluate morphological changes in Ae. aegypti eggs and embryos maintained in a climate change simulator. For this, specimens obtained from an insectarium were kept in four chambers that simulated the range of environmental scenarios predicted by the IPCC for the year 2100. The eggs obtained from each room were collected and transported to the laboratory for morphometric and morphological analysis, using confocal and scanning microscopy. Aedes aegypti eggs (n=20) were used to obtain the following variables: total width, total length, length-width ratio and diameter of the micropylar disc. Additionally, 20 embryos were used to obtain the data on head capsule length, width and length-width ratio. The data were subjected to a normality test and the means of each variable were compared using ANOVA and Tukey's post-hoc test, considering (p ≤ 0.05). A significant reduction (p < 0.05) was observed mainly in the mean lengths under the current-extreme scenario (587.5 and 553.6 µm, respectively), as well as in the widths under the current-mild scenario (171 and 158.4 µm, respectively). The length of the cephalic capsule was also affected, showing significant differences in the means under the current-intermediate scenario (189.5 and 208.5 µm, respectively), as well as in the widths between the current-intermediate scenarios (173.7 and 194.9 µm, respectively). The results suggest significant changes in the morphometry of Ae. aegypti eggs and embryos as a result of the climatic influences to which the adults were subjected, which may have an impact on vector population density and, consequently, on arbovirus dynamics in urban environments.
Asunto(s)
Aedes , Cambio Climático , Óvulo , Animales , Aedes/anatomía & histología , Aedes/crecimiento & desarrollo , Aedes/virología , Aedes/fisiología , Brasil , Mosquitos Vectores/anatomía & histología , Mosquitos Vectores/crecimiento & desarrollo , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Embrión no MamíferoRESUMEN
Fragmented landscapes in Mexico, characterized by a mix of agricultural, urban, and native vegetation cover, presents unique ecological characteristics that shape the mosquito community composition and mosquito-borne diseases. The extent to which landscape influences mosquito populations and mosquito-borne diseases is still poorly understood. This work assessed the effect of landscape metrics -agriculture, urban, and native vegetation cover- on mosquito diversity and arbovirus presence in fragmented tropical deciduous forests in Central Mexico during 2021. Among the 21 mosquito species across six genera we identified, Culex quinquefasciatus was the most prevalent species, followed by Aedes aegypti, Ae. albopictus, and Ae. epactius. Notably, areas with denser native vegetation cover displayed higher mosquito species richness, which could have an impact on phenomena such as the dilution effect. Zika and dengue virus were detected in 85% of captured species, with first reports of DENV in several Aedes species and ZIKV in multiple Aedes and Culex species. These findings underscore the necessity of expanding arbovirus surveillance beyond Ae. aegypti and advocate for a deeper understanding of vector ecology in fragmented landscapes to adequately address public health strategies.
Asunto(s)
Arbovirus , Biodiversidad , Culicidae , Mosquitos Vectores , Animales , Arbovirus/aislamiento & purificación , Arbovirus/clasificación , México/epidemiología , Mosquitos Vectores/virología , Mosquitos Vectores/clasificación , Culicidae/virología , Culicidae/clasificación , Agricultura , Aedes/virología , Aedes/clasificación , Ciudades , Virus Zika/aislamiento & purificación , Virus Zika/genética , EcosistemaRESUMEN
Using Illumina NextSeq sequencing and bioinformatics, we identified and characterized thirty-three viral sequences of unsegmented and multipartite viral families in Aedes spp., Culex sp. and Anopheles darlingi female mosquito pools from Porto São Luiz and Pirizal, Alto Pantanal. Seventeen sequences belong to unsegmented viral families, twelve represent putative novel insect-specific viruses (ISVs) within families Chuviridae (3/33; partial genomes) and coding-complete sequences of Xinmoviridae (1/33), Rhabdoviridae (2/33) and Metaviridae (6/33); and five coding-complete sequences of already-known ISVs. Notably, two putative novel rhabdoviruses, Corixo rhabdovirus 1 and 2, were phylogenetically related to Coxipo dielmovirus, but separated from other Alpharhabdovirinae genera, sharing Anopheles spp. as host. Regarding multipartite families, sixteen segments of different putative novel viruses were identified (13 coding-complete segments) within Durnavirales (4/33), Elliovirales (1/33), Hareavirales (3/33) and Reovirales (8/33) orders. Overall, this study describes twenty-eight (28/33) putative novel ISVs and five (5/33) already described viruses using metagenomics approach.
Asunto(s)
Aedes , Anopheles , Culex , Genoma Viral , Filogenia , Viroma , Animales , Brasil , Femenino , Anopheles/virología , Viroma/genética , Aedes/virología , Culex/virología , Mosquitos Vectores/virología , Secuenciación de Nucleótidos de Alto Rendimiento , Virus de Insectos/genética , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificaciónRESUMEN
Mosquitoes can transmit several pathogenic viruses to humans, but their natural viral community is also composed of a myriad of other viruses such as insect-specific viruses (ISVs) and those that infect symbiotic microorganisms. Besides a growing number of studies investigating the mosquito virome, the majority are focused on few urban species, and relatively little is known about the virome of sylvatic mosquitoes, particularly in high biodiverse biomes such as the Brazilian biomes. Here, we characterized the RNA virome of 10 sylvatic mosquito species from Atlantic forest remains at a sylvatic-urban interface in Northeast Brazil employing a metatranscriptomic approach. A total of 16 viral families were detected. The phylogenetic reconstructions of 14 viral families revealed that the majority of the sequences are putative ISVs. The phylogenetic positioning and, in most cases, the association with a high RNA-dependent RNA polymerase amino acid divergence from other known viruses suggests that the viruses characterized here represent at least 34 new viral species. Therefore, the sylvatic mosquito viral community is predominantly composed of highly divergent viruses highlighting the limited knowledge we still have about the natural virome of mosquitoes in general. Moreover, we found that none of the viruses recovered were shared between the species investigated, and only one showed high identity to a virus detected in a mosquito sampled in Peru, South America. These findings add further in-depth understanding about the interactions and coevolution between mosquitoes and viruses in natural environments. IMPORTANCE: Mosquitoes are medically important insects as they transmit pathogenic viruses to humans and animals during blood feeding. However, their natural microbiota is also composed of a diverse set of viruses that cause no harm to the insect and other hosts, such as insect-specific viruses. In this study, we characterized the RNA virome of sylvatic mosquitoes from Northeast Brazil using unbiased metatranscriptomic sequencing and in-depth bioinformatic approaches. Our analysis revealed that these mosquitoes species harbor a diverse set of highly divergent viruses, and the majority comprises new viral species. Our findings revealed many new virus lineages characterized for the first time broadening our understanding about the natural interaction between mosquitoes and viruses. Finally, it also provided several complete genomes that warrant further assessment for mosquito and vertebrate host pathogenicity and their potential interference with pathogenic arboviruses.
Asunto(s)
Culicidae , Filogenia , Viroma , Animales , Brasil , Viroma/genética , Culicidae/virología , Mosquitos Vectores/virología , Genoma Viral , ARN Viral/genética , Virus de Insectos/genética , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificación , Virus ARN/genética , Virus ARN/clasificación , Virus ARN/aislamiento & purificaciónRESUMEN
BACKGROUND: Dengue, Zika, and chikungunya, whose viruses are transmitted mainly by Aedes aegypti, significantly impact human health worldwide. Despite the recent development of promising vaccines against the dengue virus, controlling these arbovirus diseases still depends on mosquito surveillance and control. Nonetheless, several studies have shown that these measures are not sufficiently effective or ineffective. Identifying higher-risk areas in a municipality and directing control efforts towards them could improve it. One tool for this is the premise condition index (PCI); however, its measure requires visiting all buildings. We propose a novel approach capable of predicting the PCI based on facade street-level images, which we call PCINet. METHODOLOGY: Our study was conducted in Campinas, a one million-inhabitant city in São Paulo, Brazil. We surveyed 200 blocks, visited their buildings, and measured the three traditional PCI components (building and backyard conditions and shading), the facade conditions (taking pictures of them), and other characteristics. We trained a deep neural network with the pictures taken, creating a computational model that can predict buildings' conditions based on the view of their facades. We evaluated PCINet in a scenario emulating a real large-scale situation, where the model could be deployed to automatically monitor four regions of Campinas to identify risk areas. PRINCIPAL FINDINGS: PCINet produced reasonable results in differentiating the facade condition into three levels, and it is a scalable strategy to triage large areas. The entire process can be automated through data collection from facade data sources and inferences through PCINet. The facade conditions correlated highly with the building and backyard conditions and reasonably well with shading and backyard conditions. The use of street-level images and PCINet could help to optimize Ae. aegypti surveillance and control, reducing the number of in-person visits necessary to identify buildings, blocks, and neighborhoods at higher risk from mosquito and arbovirus diseases.
Asunto(s)
Aedes , Dengue , Mosquitos Vectores , Aedes/virología , Aedes/fisiología , Animales , Brasil/epidemiología , Humanos , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Dengue/prevención & control , Dengue/epidemiología , Dengue/transmisión , Ciudades , Control de Mosquitos/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/transmisiónRESUMEN
The genus Flavivirus comprises approximately 80 different viruses. Phylogenetic relationships among its members indicate a clear ecological separation between those viruses transmitted by mosquitoes, ticks, with no known vector, and insect-specific Flaviviruses. The diversity and phylogenetic relationships among insect-specific flaviviruses circulating in the central and northern regions of Argentina were studied by performing molecular detection and characterization of the NS5 protein gene in mosquitoes collected in Córdoba, Chaco and Tucumán provinces. Overall, 68 out of 1776 pools were positive. CxFV, KRV and CFAV circulate in the 3 studied provinces. Several mosquito species (Aedes aegypti, Culex bidens, Cx. dolosus, Cx. interfor, Cx. quinquefasciatus, Cx. saltanensis, Haemagogus spegazzini) were found infected. A wide circulation of CxFV was observed in the central-northern region of Argentina. CxFV strains detected in our study clustered with strains circulating in Santa Fe and Buenos Aires provinces (Argentina), and other countries such as Indonesia, Mexico, Uganda and Taiwan. The presence of these viruses in mosquitoes could play an important role from the public health perspective, because it has been shown that previous CxFV infection can increase or block the infection of the mosquito by other pathogenic flaviviruses.
Asunto(s)
Culicidae , Flavivirus , Mosquitos Vectores , Filogenia , Animales , Argentina , Flavivirus/clasificación , Flavivirus/genética , Flavivirus/aislamiento & purificación , Culicidae/virología , Culicidae/clasificación , Mosquitos Vectores/virología , Mosquitos Vectores/clasificaciónRESUMEN
Chikungunya virus (Togaviridae, Alphavirus; CHIKV) is a mosquito-borne global health threat. The main urban vector of CHIKV is the Aedes aegypti mosquito, which is found throughout Brazil. Therefore, it is important to carry out laboratory tests to assist in the virus's diagnosis and surveillance. Most molecular biology methodologies use nucleic acid extraction as the first step and require quality RNA for their execution. In this context, four RNA extraction protocols were evaluated in Ae. aegypti experimentally infected with CHIKV. Six pools were tested in triplicates (n = 18), each containing 1, 5, 10, 20, 30, or 40 mosquitoes per pool (72 tests). Four commercial kits were compared: QIAamp®, Maxwell®, PureLink®, and PureLink® with TRIzol®. The QIAamp® and PureLink® with TRIzol® kits had greater sensitivity. Two negative correlations were observed: as the number of mosquitoes per pool increases, the Ct value decreases, with a higher viral load. Significant differences were found when comparing the purity and concentration of RNA. The QIAamp® protocol performed better when it came to lower Ct values and higher RNA purity and concentration. These results may provide help in CHIKV entomovirological surveillance planning.
Asunto(s)
Aedes , Fiebre Chikungunya , Virus Chikungunya , Mosquitos Vectores , ARN Viral , Virus Chikungunya/aislamiento & purificación , Virus Chikungunya/genética , Aedes/virología , Animales , ARN Viral/aislamiento & purificación , ARN Viral/genética , Mosquitos Vectores/virología , Fiebre Chikungunya/virología , Fiebre Chikungunya/diagnóstico , Carga Viral/métodosRESUMEN
The Orthoflavivirus ilheusense (ILHV) is an arbovirus that was first isolated in Brazil in 1944 during an epidemiologic investigation of yellow fever. Is a member of the Flaviviridae family and it belongs to the antigenic complex of the Ntaya virus group. Psorophora ferox is the primary vector of ILHV and this study presents the isolation and phylogenetic analysis of ILHV in a pool of Ps. ferox collected in the state of Goiás in 2021. Viral isolation tests were performed on Vero cells and C6/36 clones. The indirect immunofluorescence test (IFI) was used to confirm the positivity of the sample. The positive sample underwent RT-qPCR, sequencing, and phylogenetic analysis. This is the first report of ILHV circulation in this municipality and presented close relationship between this isolate and another ILHV isolate collected in the city of Belém (PA).
Asunto(s)
Culicidae , Filogenia , Animales , Brasil , Células Vero , Culicidae/virología , Chlorocebus aethiops , Flavivirus/genética , Flavivirus/aislamiento & purificación , Flavivirus/clasificación , Mosquitos Vectores/virologíaRESUMEN
Zika, a viral disease transmitted to humans by Aedes mosquitoes, emerged in the Americas in 2015, causing large-scale epidemics. Colombia alone reported over 72,000 Zika cases between 2015 and 2016. Using national surveillance data from 1121 municipalities over 70 weeks, we identified sociodemographic and environmental factors associated with Zika's emergence, re-emergence, persistence, and transmission intensity in Colombia. We fitted a zero-state Markov-switching model under the Bayesian framework, assuming Zika switched between periods of presence and absence according to spatially and temporally varying probabilities of emergence/re-emergence (from absence to presence) and persistence (from presence to presence). These probabilities were assumed to follow a series of mixed multiple logistic regressions. When Zika was present, assuming that the cases follow a negative binomial distribution, we estimated the transmission intensity rate. Our results indicate that Zika emerged/re-emerged sooner and that transmission was intensified in municipalities that were more densely populated, at lower altitudes and/or with less vegetation cover. Warmer temperatures and less weekly-accumulated rain were also associated with Zika emergence. Zika cases persisted for longer in more densely populated areas with more cases reported in the previous week. Overall, population density, elevation, and temperature were identified as the main contributors to the first Zika epidemic in Colombia. We also estimated the probability of Zika presence by municipality and week, and the results suggest that the disease circulated undetected by the surveillance system on many occasions. Our results offer insights into priority areas for public health interventions against emerging and re-emerging Aedes-borne diseases.
Asunto(s)
Aedes , Cadenas de Markov , Infección por el Virus Zika , Virus Zika , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/epidemiología , Colombia/epidemiología , Humanos , Animales , Aedes/virología , Teorema de Bayes , Mosquitos Vectores/virología , Brotes de EnfermedadesRESUMEN
Zika (ZIKV) and chikungunya (CHIKV) are arboviruses that cause infections in humans and can cause clinical complications, representing a worldwide public health problem. Aedes aegypti is the primary vector of these pathogens and Culex quinquefasciatus may be a potential ZIKV vector. This study aimed to evaluate fecundity, fertility, survival, longevity, and blood feeding activity in Ae. aegypti after exposure to ZIKV and CHIKV and, in Cx. quinquefasciatus exposed to ZIKV. Three colonies were evaluated: AeCamp (Ae. aegypti-field), RecL (Ae. aegypti-laboratory) and CqSLab (Cx. quinquefasciatus-laboratory). Seven to 10 days-old females from these colonies were exposed to artificial blood feeding with CHIKV or ZIKV. CHIKV caused reduction in fecundity and fertility in AeCamp and reduction in survival and fertility in RecL. ZIKV impacted survival in RecL, fertility in AeCamp and, fecundity and fertility in CqSLab. Both viruses had no effect on blood feeding activity. These results show that CHIKV produces a higher biological cost in Ae. aegypti, compared to ZIKV, and ZIKV differently alters the biological performance in colonies of Ae. aegypti and Cx. quinquefasciatus. These results provide a better understanding over the processes of virus-vector interaction and can shed light on the complexity of arbovirus transmission.
Asunto(s)
Aedes , Virus Chikungunya , Culex , Fertilidad , Mosquitos Vectores , Infección por el Virus Zika , Virus Zika , Animales , Aedes/virología , Aedes/fisiología , Virus Chikungunya/fisiología , Virus Chikungunya/patogenicidad , Virus Zika/fisiología , Virus Zika/patogenicidad , Culex/virología , Culex/fisiología , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Femenino , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/virología , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Conducta Alimentaria/fisiología , Humanos , LongevidadRESUMEN
In the Americas, wild yellow fever (WYF) is an infectious disease that is highly lethal for some non-human primate species and non-vaccinated people. Specifically, in the Brazilian Atlantic Forest, Haemagogus leucocelaenus and Haemagogus janthinomys mosquitoes act as the major vectors. Despite transmission risk being related to vector densities, little is known about how landscape structure affects vector abundance and movement. To fill these gaps, we used vector abundance data and a model-selection approach to assess how landscape structure affects vector abundance, aiming to identify connecting elements for virus dispersion in the state of São Paulo, Brazil. Our findings show that Hg. leucocelaenus and Hg. janthinomys abundances, in highly degraded and fragmented landscapes, are mainly affected by increases in forest cover at scales of 2.0 and 2.5 km, respectively. Fragmented landscapes provide ecological corridors for vector dispersion, which, along with high vector abundance, promotes the creation of risk areas for WYF virus spread, especially along the border with Minas Gerais state, the upper edges of the Serra do Mar, in the Serra da Cantareira, and in areas of the metropolitan regions of São Paulo and Campinas.
Asunto(s)
Mosquitos Vectores , Fiebre Amarilla , Brasil , Animales , Fiebre Amarilla/transmisión , Mosquitos Vectores/virología , Ecosistema , Clima Tropical , Virus de la Fiebre Amarilla , Densidad de Población , Culicidae/virología , Culicidae/fisiologíaRESUMEN
BACKGROUND: Dengue (DENV) transmission is endemic throughout coastal Ecuador, showing heterogeneous incidence patterns in association with fine-scale variation in Aedes aegypti vector populations and other factors. Here, we investigated the impact of micro-climate and neighbourhood-level variation in urbanization on Aedes abundance, resting behaviour and associations with dengue incidence in two endemic areas. METHODOLOGY/PRINCIPAL FINDINGS: Aedes aegypti were collected in Quinindé and Portoviejo, two urban cantons with hyperendemic dengue transmission in coastal Ecuador. Aedes vectors were sampled in and around houses within urban and peri-urban neighbourhoods at four time periods. We tested for variation in vector abundance and resting behaviour in relation to neighbourhood urbanization level and microclimatic factors. Aedes abundance increased towards the end of the rainy season, was significantly higher in Portoviejo than in Quinindé, and in urban than in peri-urban neighbourhoods. Aedes vectors were more likely to rest inside houses in Portoviejo but had similar abundance in indoor and outdoor resting collections in Quinindé. Over the study period, DENV incidence was lower in Quinindé than in Portoviejo. Relationships between weekly Ae. aegypti abundance and DENV incidence were highly variable between trapping methods; with positive associations being detected only between BG-sentinel and outdoor Prokopack collections. CONCLUSIONS/SIGNIFICANCE: Aedes aegypti abundance was significantly higher in urban than peri-urban neighbourhoods, and their resting behaviour varied between study sites. This fine-scale spatial heterogeneity in Ae. aegypti abundance and behaviour could generate site-specific variation in human exposure and the effectiveness of indoor-based interventions. The trap-dependent nature of associations between Aedes abundance and local DENV incidence indicates further work is needed to identify robust entomological indicators of infection risk.
Asunto(s)
Aedes , Dengue , Mosquitos Vectores , Animales , Aedes/virología , Aedes/fisiología , Ecuador/epidemiología , Dengue/transmisión , Dengue/epidemiología , Incidencia , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Humanos , Femenino , Estaciones del AñoRESUMEN
The incidence of chikungunya has dramatically surged worldwide in recent decades, imposing an expanding burden on public health. In recent years, South America, particularly Brazil, has experienced outbreaks that have ravaged populations following the rapid dissemination of the chikungunya virus (CHIKV), which was first detected in 2014. The primary vector for CHIKV transmission is the urban mosquito species Aedes aegypti, which is highly prevalent throughout Brazil. However, the impact of the locally circulating CHIKV genotypes and specific combinations of local mosquito populations on vector competence remains unexplored. Here, we experimentally analyzed and compared the infectivity and transmissibility of the CHIKV-ECSA lineage recently isolated in Brazil among four Ae. aegypti populations collected from different regions of the country. When exposed to CHIKV-infected AG129 mice for blood feeding, all the mosquito populations displayed high infection rates and dissemination efficiency. Furthermore, we observed that all the populations were highly efficient in transmitting CHIKV to a vertebrate host (naïve AG129 mice) as early as eight days post-infection. These results demonstrate the high capacity of Brazilian Ae. aegypti populations to transmit the locally circulating CHIKV-ECSA lineage. This observation could help to explain the high prevalence of the CHIKV-ECSA lineage over the Asian lineage, which was also detected in Brazil in 2014. However, further studies comparing both lineages are necessary to gain a better understanding of the vector's importance in the epidemiology of CHIKV in the Americas.
Asunto(s)
Aedes , Fiebre Chikungunya , Virus Chikungunya , Mosquitos Vectores , Animales , Aedes/virología , Virus Chikungunya/genética , Virus Chikungunya/clasificación , Virus Chikungunya/fisiología , Virus Chikungunya/aislamiento & purificación , Brasil/epidemiología , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Fiebre Chikungunya/epidemiología , Ratones , Mosquitos Vectores/virología , Genotipo , Femenino , FilogeniaRESUMEN
Mosquitoes of vectorial importance represent a ubiquitous and constant threat of potentially devastating arboviral outbreaks. Our ability to predict such outcomes is still restricted. To answer this, we have used an extensive data collection of 23 vector and 233 non-vector mosquito species distributed throughout the Mexican territory and linked them to social and environmental factors. Our aim was to predict vector and non-vector mosquitoes' distribution and species richness based on socioeconomic and environmental data. We found that lack of health services, human population variation, ecological degradation, and urban-rural categorization contributed significantly to explain the distribution of vector mosquitoes. mosquitoes. This phenomenon is probably attributed to the degradation of natural ecosystems as it creates favorable conditions for the proliferation of vector mosquitoes. The richness of vector mosquitoes was similarly explained by most of these variables as well as altitude. As for non-vector mosquitoes, social marginalization, ecological degradation, anthropogenic impact, and altitude explain species richness and distribution. These findings illustrate the complex interaction of environmental and socioeconomic factors behind the distribution of mosquitoes, and the potential for arboviral disease outbreaks. Areas with human populations at highest risk for mosquito-borne diseases should be primary targets for vector control.