RESUMEN
Alphavirus infections are transmitted by mosquitoes, but the mode of transmission for Mycobacterium ulcerans, which causes Buruli ulcer, is contested. Using notification data for Victoria, Australia, during 2017-2022, adjusted for incubation period, we show close alignment between alphavirus and Buruli ulcer seasons, supporting the hypothesis of mosquito transmission of M. ulcerans.
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Infecciones por Alphavirus , Úlcera de Buruli , Mosquitos Vectores , Mycobacterium ulcerans , Úlcera de Buruli/transmisión , Úlcera de Buruli/epidemiología , Úlcera de Buruli/microbiología , Mycobacterium ulcerans/aislamiento & purificación , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/epidemiología , Humanos , Animales , Victoria/epidemiología , Mosquitos Vectores/microbiología , Mosquitos Vectores/virología , Alphavirus/aislamiento & purificación , Culicidae/microbiología , Culicidae/virología , Notificación de EnfermedadesRESUMEN
BACKGROUND: Mayaro virus (MAYV) is an emerging alphavirus, primarily transmitted by the mosquito Haemagogus janthinomys in Central and South America. However, recent studies have shown that Aedes aegypti, Aedes albopictus and various Anopheles mosquitoes can also transmit the virus under laboratory conditions. MAYV causes sporadic outbreaks across the South American region, particularly in areas near forests. Recently, cases have been reported in European and North American travelers returning from endemic areas, raising concerns about potential introductions into new regions. This study aims to assess the vector competence of three potential vectors for MAYV present in Europe. METHODS: Aedes albopictus from Italy, Anopheles atroparvus from Spain and Culex pipiens biotype molestus from Belgium were exposed to MAYV and maintained under controlled environmental conditions. Saliva was collected through a salivation assay at 7 and 14 days post-infection (dpi), followed by vector dissection. Viral titers were determined using focus forming assays, and infection rates, dissemination rates, and transmission efficiency were calculated. RESULTS: Results indicate that Ae. albopictus and An. atroparvus from Italy and Spain, respectively, are competent vectors for MAYV, with transmission possible starting from 7 dpi under laboratory conditions. In contrast, Cx. pipiens bioform molestus was unable to support MAYV infection, indicating its inability to contribute to the transmission cycle. CONCLUSIONS: In the event of accidental MAYV introduction in European territories, autochthonous outbreaks could potentially be sustained by two European species: Ae. albopictus and An. atroparvus. Entomological surveillance should also consider certain Anopheles species when monitoring MAYV transmission.
Asunto(s)
Aedes , Infecciones por Alphavirus , Alphavirus , Culex , Mosquitos Vectores , Animales , Aedes/virología , Mosquitos Vectores/virología , Alphavirus/fisiología , Alphavirus/aislamiento & purificación , Culex/virología , Europa (Continente) , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Saliva/virología , Anopheles/virología , España , Italia , Femenino , BélgicaAsunto(s)
Infecciones por Alphavirus , Virus del Río Ross , Humanos , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/epidemiología , Infecciones por Alphavirus/virología , Virus del Río Ross/aislamiento & purificación , Queensland/epidemiología , Animales , Mosquitos Vectores/virología , Culicidae/virologíaRESUMEN
Mayaro virus (MAYV; Alphavirus: Togaviridae) is an emerging pathogen in Latin America, causing fever and polyarthritis. Sporadic outbreaks of MAYV have occurred in the region, with reported human cases being imported to Europe and North America. Although primarily a risk for those residing in the Amazon basin's tropical forests, recent reports highlight that urbanization would increase the risk of MAYV transmission in Latin America. Urban emergence depends on human susceptibility and the ability of mosquitos like Aedes aegypti (Linnaeus, 1762) (Diptera: Culicidae) to transmit MAYV. Despite the absence of active MAYV transmission in Argentine, the risk of introduction is substantial due to human movement and the presence of Ae. aegypti in the region. This study aimed to evaluate the susceptibility of different Argentine Ae. aegypti populations to MAYV genotype L (MAYV-L) using dose-response assays and determine barriers to virus infection, dissemination and transmission. Immature mosquito stages were collected in Buenos Aires, Córdoba and Rosario cities. Female Ae. aegypti (F2) were orally infected by feeding on five concentrations of MAYV-L, ranging from 1.0 to 6.0 log10 PFU/mL. Abdomens, legs and saliva were analysed using viral plaque assays. Results revealed that MAYV-L between infection and dissemination were associated with viral doses rather than the population origin. Infection rates varied between 3% and 65%, with a 50% infectious dose >5.5 log10 PFU/mL. Dissemination occurred at 39%, with a 50% dissemination dose of ~6.0 log10 PFU/mL. Dissemination among infected mosquitoes ranged from 60% to 86%, and transmission from disseminated mosquitoes ranged from 11% to 20%. Argentine Ae. aegypti populations exhibited a need for higher viral doses of MAYV-L than those typically found in humans to become infected. In addition, only a small proportion of infected mosquitoes were capable of transmitting the virus. Understanding MAYV transmission in urban areas is crucial for public health interventions.
Asunto(s)
Aedes , Alphavirus , Mosquitos Vectores , Animales , Aedes/virología , Aedes/fisiología , Argentina , Mosquitos Vectores/virología , Mosquitos Vectores/fisiología , Alphavirus/fisiología , Femenino , Infecciones por Alphavirus/transmisión , Larva/virología , Larva/crecimiento & desarrolloRESUMEN
Improving our understanding of Mayaro virus (MAYV) ecology is critical to guide surveillance and risk assessment. We conducted a PRISMA-adherent systematic review of the published and grey literature to identify potential arthropod vectors and non-human animal reservoirs of MAYV. We searched PubMed/MEDLINE, Embase, Web of Science, SciELO and grey-literature sources including PAHO databases and dissertation repositories. Studies were included if they assessed MAYV virological/immunological measured occurrence in field-caught, domestic, or sentinel animals or in field-caught arthropods. We conducted an animal seroprevalence meta-analysis using a random effects model. We compiled granular georeferenced maps of non-human MAYV occurrence and graded the quality of the studies using a customized framework. Overall, 57 studies were eligible out of 1523 screened, published between the years 1961 and 2020. Seventeen studies reported MAYV positivity in wild mammals, birds, or reptiles and five studies reported MAYV positivity in domestic animals. MAYV positivity was reported in 12 orders of wild-caught vertebrates, most frequently in the orders Charadriiformes and Primate. Sixteen studies detected MAYV in wild-caught mosquito genera including Haemagogus, Aedes, Culex, Psorophora, Coquillettidia, and Sabethes. Vertebrate animals or arthropods with MAYV were detected in Brazil, Panama, Peru, French Guiana, Colombia, Trinidad, Venezuela, Argentina, and Paraguay. Among non-human vertebrates, the Primate order had the highest pooled seroprevalence at 13.1% (95% CI: 4.3-25.1%). From the three most studied primate genera we found the highest seroprevalence was in Alouatta (32.2%, 95% CI: 0.0-79.2%), followed by Callithrix (17.8%, 95% CI: 8.6-28.5%), and Cebus/Sapajus (3.7%, 95% CI: 0.0-11.1%). We further found that MAYV occurs in a wide range of vectors beyond Haemagogus spp. The quality of evidence behind these findings was variable and prompts calls for standardization of reporting of arbovirus occurrence. These findings support further risk emergence prediction, guide field surveillance efforts, and prompt further in-vivo studies to better define the ecological drivers of MAYV maintenance and potential for emergence.
Asunto(s)
Infecciones por Alphavirus/veterinaria , Infecciones por Alphavirus/virología , Alphavirus/fisiología , Vectores Artrópodos/virología , Reservorios de Enfermedades/virología , Mosquitos Vectores/virología , Alphavirus/genética , Infecciones por Alphavirus/transmisión , Animales , Vectores Artrópodos/fisiología , Aves/virología , Humanos , Mamíferos/virología , Mosquitos Vectores/fisiología , Primates/virología , Reptiles/virologíaRESUMEN
Viral disease poses a major barrier to sustainable aquaculture, with outbreaks causing large economic losses and growing concerns for fish welfare. Genomic epidemiology can support disease control by providing rapid inferences on viral evolution and disease transmission. In this study, genomic epidemiology was used to investigate salmonid alphavirus (SAV), the causative agent of pancreas disease (PD) in Atlantic salmon. Our aim was to reconstruct SAV subtype-2 (SAV2) diversity and transmission dynamics in recent Norwegian aquaculture, including the origin of SAV2 in regions where this subtype is not tolerated under current legislation. Using nanopore sequencing, we captured ~90% of the SAV2 genome for n = 68 field isolates from 10 aquaculture production regions sampled between 2018 and 2020. Using time-calibrated phylogenetics, we infer that, following its introduction to Norway around 2010, SAV2 split into two clades (SAV2a and 2b) around 2013. While co-present at the same sites near the boundary of Møre og Romsdal and Trøndelag, SAV2a and 2b were generally detected in non-overlapping locations at more Southern and Northern latitudes, respectively. We provide evidence for recent SAV2 transmission over large distances, revealing a strong connection between Møre og Romsdal and SAV2 detected in 2019/20 in Rogaland. We also demonstrate separate introductions of SAV2a and 2b outside the SAV2 zone in Sognefjorden (Vestland), connected to samples from Møre og Romsdal and Trøndelag, respectively, and a likely 100 km Northward transmission of SAV2b within Trøndelag. Finally, we recovered genomes of SAV2a and SAV3 co-infecting single fish in Rogaland, involving novel SAV3 lineages that diverged from previously characterized strains >25 years ago. Overall, this study demonstrates useful applications of genomic epidemiology for tracking viral disease spread in aquaculture.
Asunto(s)
Infecciones por Alphavirus/veterinaria , Alphavirus/genética , Enfermedades de los Peces/transmisión , Salmonidae/virología , Alphavirus/clasificación , Infecciones por Alphavirus/transmisión , Animales , Acuicultura , Variación Genética , Genoma Viral , FilogeografíaRESUMEN
Mayaro virus (MAYV) is a neglected arthropod-borne virus found in the Americas. MAYV infection results in Mayaro fever, a non-lethal debilitating disease characterized by a strong inflammatory response affecting the joints and muscles. MAYV was once considered endemic to forested areas in Brazil but has managed to adapt and spread to urban regions using new vectors, such as Aedes aegypti, and has the potential to cause serious epidemics in the future. Currently, there are no vaccines or specific treatments against MAYV. In this study, the antiviral activity of a series of synthetic cyclic ketones were evaluated for the first time against MAYV. Twenty-four compounds were screened in a cell viability assay, and eight were selected for further evaluation. Effective concentration (EC50) and selectivity index (SI) were calculated and compound 9-(5-(4-chlorophenyl]furan-2-yl)-3,6-dimethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2))-dione (9) (EC50 = 21.5 µmol·L-1, SI = 15.8) was selected for mechanism of action assays. The substance was able to reduce viral activity by approximately 70% in both pre-treatment and post-treatment assays.
Asunto(s)
Infecciones por Alphavirus/virología , Alphavirus/efectos de los fármacos , Antivirales/farmacología , Cetonas/farmacología , Aedes/virología , Alphavirus/fisiología , Infecciones por Alphavirus/tratamiento farmacológico , Infecciones por Alphavirus/transmisión , Animales , Antivirales/química , Brasil , Evaluación Preclínica de Medicamentos , Humanos , Cetonas/química , Mosquitos Vectores/virologíaRESUMEN
Salmon pancreas disease virus (SPDV) has been affecting the salmon farming industry for over 30 years, but despite the substantial amount of studies, there are still a number of recognized knowledge gaps, for example in the transmission of the virus. In this work, an ultrastructural morphological approach was used to describe observations after infection by SPDV of an ex vivo cardiac model generated from Atlantic salmon embryos. The observations in this study and those available on previous ultrastructural work on SPDV are compared and contrasted with the current knowledge on terrestrial mammalian and insect alphaviral replication cycles, which is deeper than that of SPDV both morphologically and mechanistically. Despite their limitations, morphological descriptions remain an excellent way to generate novel hypotheses, and this has been the aim of this work. This study has used a target host, ex vivo model and resulted in some previously undescribed features, including filopodial membrane projections, cytoplasmic stress granules or putative intracytoplasmic budding. The latter suggests a new hypothesis that warrants further mechanistic research: SPDV in salmon may have retained the capacity for non-cytolytic (persistent) infections by intracellular budding, similar to that noted in arthropod vectors of other alphaviruses. In the notable absence of a known intermediate host for SPDV, the presence of this pattern suggests that both cytopathic and persistent infections may coexist in the same host. It is our hope that the ultrastructural comparison presented here stimulates new research that brings the knowledge on SPDV replication cycle up to a similar level to that of terrestrial alphaviruses.
Asunto(s)
Infecciones por Alphavirus/veterinaria , Alphavirus/fisiología , Replicación Viral/fisiología , Alphavirus/ultraestructura , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Animales , Enfermedades de los Peces/virología , Interacciones Huésped-Patógeno , Microscopía Electrónica , Salmo salar , Técnicas de Cultivo de TejidosRESUMEN
Identifying the key vector and host species that drive the transmission of zoonotic pathogens is notoriously difficult but critical for disease control. We present a nested approach for quantifying the importance of host and vectors that integrates species' physiological competence with their ecological traits. We apply this framework to a medically important arbovirus, Ross River virus (RRV), in Brisbane, Australia. We find that vertebrate hosts with high physiological competence are not the most important for community transmission; interactions between hosts and vectors largely underpin the importance of host species. For vectors, physiological competence is highly important. Our results identify primary and secondary vectors of RRV and suggest two potential transmission cycles in Brisbane: an enzootic cycle involving birds and an urban cycle involving humans. The framework accounts for uncertainty from each fitted statistical model in estimates of species' contributions to transmission and has has direct application to other zoonotic pathogens.
Asunto(s)
Infecciones por Alphavirus/virología , Aves/virología , Culicidae/virología , Reservorios de Enfermedades/virología , Vectores de Enfermedades , Virus del Río Ross/patogenicidad , Zoonosis Virales , Infecciones por Alphavirus/transmisión , Animales , Interacciones Huésped-Patógeno , Humanos , Modelos Biológicos , Queensland , VirulenciaRESUMEN
Mayaro virus (MAYV), which causes mayaro fever, is endemic to limited regions of South America that may expand due to the possible involvement of Aedes spp. mosquitoes in its transmission. Its effective control will require the accurate identification of infected individuals, which has been restricted to nucleic acid-based tests due to similarities with other emerging members of the Alphavirus genus of the Togaviridae family; both in structure and clinical symptoms. Serological tests have a more significant potential to expand testing at a reasonable cost, and their performance primarily reflects that of the antigen utilized to capture pathogen-specific antibodies. Here, we describe the assembly of a synthetic gene encoding multiple copies of antigenic determinants mapped from the nsP1, nsP2, E1, and E2 proteins of MAYV that readily expressed as a stable chimeric protein in bacteria. Its serological performance as the target in ELISAs revealed a high accuracy for detecting anti-MAYV IgM antibodies. No cross-reactivity was observed with serum from seropositive individuals for dengue, chikungunya, yellow fever, Zika, and other infectious diseases as well as healthy individuals. Our data suggest that this bioengineered antigen could be used to develop high-performance serological tests for MAYV infections.
Asunto(s)
Infecciones por Alphavirus/diagnóstico , Alphavirus/inmunología , Epítopos/inmunología , Infecciones por Togaviridae/diagnóstico , Aedes/virología , Alphavirus/patogenicidad , Infecciones por Alphavirus/inmunología , Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Animales , Ensayo de Inmunoadsorción Enzimática , Epítopos/genética , Epítopos/ultraestructura , Femenino , Genes Sintéticos/genética , Genes Sintéticos/inmunología , Humanos , Inmunoglobulina M/inmunología , Masculino , Pruebas Serológicas , América del Sur/epidemiología , Togaviridae/aislamiento & purificación , Togaviridae/patogenicidad , Infecciones por Togaviridae/inmunología , Infecciones por Togaviridae/transmisión , Infecciones por Togaviridae/virologíaRESUMEN
We describe the impact of COVID-19 mitigation measures on mosquito-borne diseases in Queensland, Australia, during the first half of 2020. Implementation of restrictions coincided with an atypical late season outbreak of Ross River virus (RRV) characterized by a peak in notifications in April (1173) and May (955) which were greater than 3-fold the mean observed for the previous four years. We propose that limitations on human movement likely resulted in the majority of RRV infections being acquired at or near the place of residence, and that an increase in outdoor activities, such as gardening and bushwalking in the local household vicinity, increased risk of exposure to RRV-infected mosquitoes. In contrast, the precipitous decline in international passenger flights led to a reduction in the number of imported dengue and malaria cases of over 70% and 60%, respectively, compared with the previous five years. This substantial reduction in flights also reduced a risk pathway for importation of exotic mosquitoes, but the risk posed by importation via sea cargo was not affected. Overall, the emergence of COVID-19 has had a varied impact on mosquito-borne disease epidemiology in Queensland, but the need for mosquito surveillance and control, together with encouragement of personal protective measures, remains unchanged.
Asunto(s)
COVID-19/prevención & control , Brotes de Enfermedades/prevención & control , Vigilancia de la Población , Enfermedades Transmitidas por Vectores/epidemiología , Infecciones por Alphavirus/epidemiología , Infecciones por Alphavirus/transmisión , Animales , COVID-19/epidemiología , Control de Enfermedades Transmisibles/métodos , Control de Enfermedades Transmisibles/estadística & datos numéricos , Culicidae/virología , Brotes de Enfermedades/estadística & datos numéricos , Humanos , Movimiento , Queensland/epidemiología , Viaje , Enfermedades Transmitidas por Vectores/prevención & control , Enfermedades Transmitidas por Vectores/transmisiónRESUMEN
BACKGROUND: Statistical models are regularly used in the forecasting and surveillance of infectious diseases to guide public health. Variable selection assists in determining factors associated with disease transmission, however, often overlooked in this process is the evaluation and suitability of the statistical model used in forecasting disease transmission and outbreaks. Here we aim to evaluate several modelling methods to optimise predictive modelling of Ross River virus (RRV) disease notifications and outbreaks in epidemiological important regions of Victoria and Western Australia. METHODOLOGY/PRINCIPAL FINDINGS: We developed several statistical methods using meteorological and RRV surveillance data from July 2000 until June 2018 in Victoria and from July 1991 until June 2018 in Western Australia. Models were developed for 11 Local Government Areas (LGAs) in Victoria and seven LGAs in Western Australia. We found generalised additive models and generalised boosted regression models, and generalised additive models and negative binomial models to be the best fit models when predicting RRV outbreaks and notifications, respectively. No association was found with a model's ability to predict RRV notifications in LGAs with greater RRV activity, or for outbreak predictions to have a higher accuracy in LGAs with greater RRV notifications. Moreover, we assessed the use of factor analysis to generate independent variables used in predictive modelling. In the majority of LGAs, this method did not result in better model predictive performance. CONCLUSIONS/SIGNIFICANCE: We demonstrate that models which are developed and used for predicting disease notifications may not be suitable for predicting disease outbreaks, or vice versa. Furthermore, poor predictive performance in modelling disease transmissions may be the result of inappropriate model selection methods. Our findings provide approaches and methods to facilitate the selection of the best fit statistical model for predicting mosquito-borne disease notifications and outbreaks used for disease surveillance.
Asunto(s)
Infecciones por Alphavirus/epidemiología , Modelos Estadísticos , Virus del Río Ross , Infecciones por Alphavirus/transmisión , Brotes de Enfermedades , Humanos , Conceptos MeteorológicosRESUMEN
Koala populations in many areas of Australia have declined sharply in response to habitat loss, disease and the effects of climate change. Koalas may face further morbidity from endemic mosquito-borne viruses, but the impact of such viruses is currently unknown. Few seroprevalence studies in the wild exist and little is known of the determinants of exposure. Here, we exploited a large, spatially and temporally explicit koala survey to define the intensity of Ross River Virus (RRV) exposure in koalas residing in urban coastal environments in southeast Queensland, Australia. We demonstrate that RRV exposure in koalas is much higher (> 80%) than reported in other sero-surveys and that exposure is uniform across the urban coastal landscape. Uniformity in exposure is related to the presence of the major RRV mosquito vector, Culex annulirostris, and similarities in animal movement, tree use, and age-dependent increases in exposure risk. Elevated exposure ultimately appears to result from the confinement of remaining coastal koala habitat to the edges of permanent wetlands unsuitable for urban development and which produce large numbers of competent mosquito vectors. The results further illustrate that koalas and other RRV-susceptible vertebrates may serve as useful sentinels of human urban exposure in endemic areas.
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Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Phascolarctidae/virología , Virus del Río Ross/patogenicidad , Animales , Culex/virología , Ecosistema , Humanos , Mosquitos Vectores/virología , Queensland , Estudios Seroepidemiológicos , HumedalesRESUMEN
Alphaviruses such as chikungunya and western equine encephalitis viruses are important human pathogens transmitted by mosquitoes that have recently caused large epidemic and epizootic outbreaks. The epidemic potential of alphaviruses is often related to enhanced mosquito transmission. Tissue barriers and antiviral responses impose bottlenecks to viral populations in mosquitoes. Substitutions in the envelope proteins and the presence of repeated sequence elements (RSEs) in the 3'UTR of epidemic viruses were proposed to be specifically associated to efficient replication in mosquito vectors. Here, we discuss the molecular mechanisms that originated RSEs, the evolutionary forces that shape the 3'UTR of alphaviruses, and the significance of RSEs for mosquito transmission. Finally, the presence of RSEs in the 3'UTR of viral genomes appears as evolutionary trait associated to mosquito adaptation and emerges as a common feature among viruses from the alphavirus and flavivirus genera.
Asunto(s)
Infecciones por Alphavirus/transmisión , Virus Chikungunya/genética , Virus de la Encefalitis Equina del Oeste/genética , Infecciones por Flavivirus/transmisión , Flavivirus/genética , Genoma Viral , Proteínas del Envoltorio Viral/genética , Regiones no Traducidas 3' , Infecciones por Alphavirus/virología , Animales , Virus Chikungunya/clasificación , Virus Chikungunya/patogenicidad , Culicidae/virología , Virus de la Encefalitis Equina del Oeste/clasificación , Virus de la Encefalitis Equina del Oeste/patogenicidad , Flavivirus/clasificación , Flavivirus/patogenicidad , Infecciones por Flavivirus/virología , Regulación de la Expresión Génica , Humanos , Repeticiones de Microsatélite , Mosquitos Vectores/virología , Filogenia , Transducción de Señal , Proteínas del Envoltorio Viral/metabolismo , Replicación ViralRESUMEN
BACKGROUND: Mayaro virus (MAYV; Alphavirus, Togaviridae) is an emerging pathogen endemic in South American countries. The increase in intercontinental travel and tourism-based forest excursions has resulted in an increase in MAYV spread, with imported cases observed in Europe and North America. Intriguingly, no local transmission of MAYV has been reported outside South America, despite the presence of potential vectors. METHODS: We assessed the vector competence of Aedes albopictus from New York and Anopheles quadrimaculatus for MAYV. RESULTS: The results show that Ae. albopictus from New York and An. quadrimaculatus are competent vectors for MAYV. However, Ae. albopictus was more susceptible to infection. Transmission rates increased with time for both species, with rates of 37.16 and 64.44% for Ae. albopictus, and of 25.15 and 48.44% for An. quadrimaculatus, respectively, at 7 and 14 days post-infection. CONCLUSIONS: Our results suggest there is a risk of further MAYV spread throughout the Americas and autochthonous transmission in the USA. Preventive measures, such as mosquito surveillance of MAYV, will be essential for early detection.
Asunto(s)
Aedes/virología , Infecciones por Alphavirus/transmisión , Alphavirus , Anopheles/virología , Mosquitos Vectores/virología , Animales , Humanos , New York , Saliva/virología , Estados UnidosRESUMEN
A crucial, but unresolved question concerning mosquito-borne virus transmission is how these viruses can remain endemic in regions where the transmission is halted for long periods of time, due to mosquito inactivity in, e.g., winter. In northern Europe, Sindbis virus (SINV) (genus alphavirus, Togaviridae) is transmitted among birds by Culex mosquitoes during the summer, with occasional symptomatic infections occurring in humans. In winter 2018-19, we sampled hibernating Culex spp females in a SINV endemic region in Sweden and assessed them individually for SINV infection status, blood-feeding status, and species. The results showed that 35 out of the 767 collected mosquitoes were infected by SINV, i.e., an infection rate of 4.6%. The vast majority of the collected mosquitoes had not previously blood-fed (98.4%) and were of the species Cx. pipiens (99.5%). This is the first study of SINV overwintering, and it concludes that SINV can be commonly found in the hibernating Cx. pipiens population in an endemic region in Sweden, and that these mosquitoes become infected through other means besides blood-feeding. Further studies on mosquito ecology and viral interactions are needed to elucidate the mechanisms of the persistence of these viruses over winter.
Asunto(s)
Infecciones por Alphavirus/epidemiología , Infecciones por Alphavirus/virología , Culex/virología , Mosquitos Vectores/virología , Virus Sindbis/fisiología , Infecciones por Alphavirus/transmisión , Animales , Vigilancia en Salud Pública , ARN Viral , Estaciones del Año , Suecia/epidemiologíaRESUMEN
RNA of Kyzylagach virus (KYZV), a Sindbis-like mosquito-borne alphavirus from Western equine encephalitis virus complex, was detected in four pools (out of 221 pools examined), encompassing 10,784 female Culex modestus mosquitoes collected at a fishpond in south Moravia, Czech Republic, with a minimum infection rate of 0.04%. This alphavirus was never detected in Central Europe before.
Asunto(s)
Infecciones por Alphavirus/transmisión , Infecciones por Alphavirus/virología , Culicidae/virología , Mosquitos Vectores/virología , Virus Sindbis , Animales , Europa (Continente)/epidemiología , FemeninoRESUMEN
BACKGROUND: Ross River virus (RRV) is responsible for the most common vector-borne disease of humans reported in Australia. The virus circulates in enzootic cycles between multiple species of mosquitoes, wildlife reservoir hosts and humans. Public health concern about RRV is increasing due to rising incidence rates in Australian urban centres, along with increased circulation in Pacific Island countries. Australia experienced its largest recorded outbreak of 9544 cases in 2015, with the majority reported from south east Queensland (SEQ). This study examined potential links between disease patterns and transmission pathways of RRV. METHODS: The spatial and temporal distribution of notified RRV cases, and associated epidemiological features in SEQ, were analysed for the period 2001-2016. This included fine-scale analysis of disease patterns across the suburbs of the capital city of Brisbane, and those of 8 adjacent Local Government Areas, and host spot analyses to identify locations with significantly high incidence. RESULTS: The mean annual incidence rate for the region was 41/100,000 with a consistent seasonal peak in cases between February and May. The highest RRV incidence was in adults aged from 30 to 64 years (mean incidence rate: 59/100,000), and females had higher incidence rates than males (mean incidence rates: 44/100,000 and 34/100,000, respectively). Spatial patterns of disease were heterogeneous between years, and there was a wide distribution of disease across both urban and rural areas of SEQ. Overall, the highest incidence rates were reported from predominantly rural suburbs to the north of Brisbane City, with significant hot spots located in peri-urban suburbs where residential, agricultural and conserved natural land use types intersect. CONCLUSIONS: Although RRV is endemic across all of SEQ, transmission is most concentrated in areas where urban and peri-urban environments intersect. The drivers of RRV transmission across rural-urban landscapes should be prioritised for further investigation, including identification of specific vectors and hosts that mediate human spillover.
Asunto(s)
Infecciones por Alphavirus/epidemiología , Virus del Río Ross , Adulto , Infecciones por Alphavirus/transmisión , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Queensland/epidemiología , Salud Rural , Salud UrbanaRESUMEN
BACKGROUND: Mayaro virus (Togaviridae) is an endemic arbovirus of the Americas with epidemiological similarities with the agents of other more prominent diseases such as dengue (Flaviviridae), Zika (Flaviviridae), and chikungunya (Togaviridae). It is naturally transmitted in a sylvatic/rural cycle by Haemagogus spp., but, potentially, it could be incorporated and transmitted in an urban cycle by Aedes aegypti, a vector widely disseminated in the Americas. METHODS: The Mayaro arbovirus dynamics was simulated mathematically in the colombian population in the eight biogeographical provinces, bearing in mind the vector's population movement between provinces through passive transport via truck cargo. The parameters involved in the virus epidemiological dynamics, as well as the vital rates of Ae. aegypti in each of the biogeographical provinces were obtained from the literature. These data were included in a meta-population model in differential equations, represented by a model structured by age for the dynamic population of Ae. aegypti combined with an epidemiological SEI/SEIR-type model. In addition, the model was incorporated with a term of migration to represent the connectivity between the biogeographical provinces. RESULTS: The vital rates and the development cycle of Ae. aegypti varied between provinces, having greater biological potential between 23 °C and 28 °C in provinces of Imerí, biogeographical Chocó, and Magdalena, with respect to the North-Andean Moorland (9.33-21.38 °C). Magdalena and Maracaibo had the highest flow of land cargo. The results of the simulations indicate that Magdalena, Imerí, and biogeographical Chocó would be the most affected regarding the number of cases of people infected by Mayaro virus over time. CONCLUSIONS: The temperature in each of the provinces influences the local population dynamics of Ae. aegypti and passive migration via transport of land cargo plays an important role on how the Mayaro virus would be disseminated in the human population. Once this arbovirus begins an urban cycle, the most-affected departments would be Antioquia, Santander, Norte de Santander, Cesar (Provinces of Magdalena), and Valle del Cauca, and Chocó (biogeographical province of Chocó), which is why vector control programmes must aim their efforts at these departments and include some type of vector control to the transport of land cargo to avoid a future Mayaro epidemic.