Factores asociados con malaria y arboviriasis en pacientes con síndrome febril importado: estudio de cohortes retrospectivo / Factors associated with malaria and arboviral disease in patients with imported febrile syndrome: a retrospective cohort study

Objetivos: Definir variables predictoras de malaria y arboviriasis en pacientes que consultan por síndrome febril tras la vuelta de un viaje a zonas tropicales/subtropicales. Método: Estudio de cohortes retrospectivo. Se incluyeron variables demográficas, epidemiológicas, clínicas, analíticas y el diagnóstico final clínico y microbiológico. Se realizó un análisis multivariante y se calcularon los índices de exactitud diagnóstica (sensibilidad, especificidad, valores predictivos) y cocientes de probabilidad de la combinación de dichas variables. Resultados: Se incluyeron 291 pacientes con síndrome febril, 108 tenían malaria (37,1%), 28 arboviriasis (9,6%) y 155 otras causas de fiebre (53,3%). En el análisis multivariante, los pacientes con síndrome febril con más riesgo de padecer malaria fueron los que procedían de África subsahariana [odds ratio ajustado (ORa): 45,85; IC 95%: 9,45-222,49], eran inmigrantes que visitan a familiares y amigos (VFA) (ORa = 3,55; IC 95%: 1,21-10,46), presentaban cifras de plaquetas < 150.000/mm3 (ORa = 16,47; IC 95%: 5,46-49,70) o cefalea (ORa = 10,62; IC 95%: 3,20-35,28). La combinación de estas cuatro variables tiene un cociente de probabilidad positivo (CPP) de 23,72 (IC 95%: 5,76-97,62). Los pacientes con síndrome febril que tienen más riesgo de padecer arboviriasis eran los que procedían de Centroamérica y Sudamérica (OR = 5,07; IC 95%: 1,73-14,92), presentaban exantema (OR = 5,10; IC 95%: 1,72-17,02) o artromialgias (OR = 14,50; IC 95%: 3,05-68,80). La combinación de estas tres variables tiene un CPP de 20,66 (IC 95%: 7,74-55,21). Conclusiones: Los pacientes con síndrome febril que tienen más riesgo de padecer malaria son los que procedían de África subsahariana, eran VFA, presentaban cifras de plaquetas < 150.000/μl o cefalea, y tenían mayor riesgo de padecer arboviriasis si procedían de Centroamérica y Sudamérica, presentaban exantema o artromialgias. (AU)

Objective: To identify predictors of malaria and arboviral disease in patients with febrile syndrome who seek care after traveling from tropical or subtropical locations. Methods: Observational retrospective cohort study. We collected demographic, epidemiologic, and clinical data; laboratory findings; and the clinical and final microbiologic diagnoses. Multivariate analysis was used to calculate indices of diagnostic accuracy (sensitivity, specificity, and predictive values) and coefficients of probability of combinations of variables. Results: Data for 291 patients with febrile syndrome were included; 108 had malaria (37.1%), 28 had an arboviral disease (9.6%), and 155 had other causes of fever (53.3%). Multivariate analysis showed patients most likely to have malaria were those from sub-Saharan Africa, adjusted odds ratio (aOR) of 45.85 (95% CI, 9.45-222.49); immigrants who returned to visit friends and relatives (VFR), aOR of 3.55 (95% CI, 1.21-10.46); or had platelet concentrations <150 000/mm3, aORa of 16.47 (95% CI, 5.46-49.70) or headache, aOR of 10.62 (95% CI, 3.20-35.28). The combination of these 4 variables gave a positive probability coefficient (PPC) of 23.72 (95% CI, 5.76-97.62). Patients with febrile syndrome most likely to have an arboviral disease were those from Central or South America, OR 5.07 (95% CI, 1.73-14.92), and those who had exanthems, OR 5.10 (95% CI, 1.72-17.02) or joint pain, OR 14.50 (95% CI, 3.05-68.80). The combination of these 3 variables gave a PPC of 20.66 (95% CI, 7.74-55.21). Conclusions: Patients with febrile syndrome with the greatest probability of having malaria are those from sub-Saharan Africa, those who are VFR, and those with platelet concentrations under 150.000/μL or headache. Arboviral disease wasmore likely in patients from Central and South America who had exanthems or joint pain. (AU)

Arboviruses and symbiotic viruses cooperatively hijack insect sperm-specific proteins for paternal transmission.

Arboviruses and symbiotic viruses can be paternally transmitted by male insects to their offspring for long-term viral persistence in nature, but the mechanism remains largely unknown. Here, we identify the sperm-specific serpin protein HongrES1 of leafhopper Recilia dorsalis as a mediator of paternal transmission of the reovirus Rice gall dwarf virus (RGDV) and a previously undescribed symbiotic virus of the Virgaviridae family, Recilia dorsalis filamentous virus (RdFV). We show that HongrES1 mediates the direct binding of virions to leafhopper sperm surfaces and subsequent paternal transmission via interaction with both viral capsid proteins. Direct interaction of viral capsid proteins mediates simultaneously invasion of two viruses into male reproductive organs. Moreover, arbovirus activates HongrES1 expression to suppress the conversion of prophenoloxidase to active phenoloxidase, potentially producing a mild antiviral melanization defense. Paternal virus transmission scarcely affects offspring fitness. These findings provide insights into how different viruses cooperatively hijack insect sperm-specific proteins for paternal transmission without disturbing sperm functions.

Genetic characterization of the rare Bruconha virus (Bunyavirales: Orthobunyavirus) isolated in Vale do Ribeira (Atlantic Forest biome), Southeastern Brazil.

Brazil is a great source of arbovirus diversity, mainly in the Amazon region. However, other biomes, especially the Atlantic Forest, may also be a hotspot for emerging viruses, including Bunyaviruses (Negarnaviricota: Bunyavirales). For instance, Vale do Ribeira, located in the Southeastern region, has been widely studied for virus surveillance, where Flavivirus, Alphavirus and Bunyaviruses were isolated during the last decades, including Bruconha virus (BRCV), a member of Orthobunyavirus genus Group C, in 1976. Recently, a new isolate of BRCV named Span321532 was obtained from an adult sentinel mouse placed in Iguape city in 2011, and a full-length genome was generated with nucleotide differences ranging between 1.5%, 5.3% and 5% (L, M and S segments, respectively) from the prototype isolated 35 years earlier. In addition, each segment placed BRCV into different clusters, showing the high variety within Bunyavirales. Although no evidence for reassortants was detected, this finding reiterates the need for new surveillance and genomic studies in the area considering the high mutation rates of arbovirus, and also to identify the hosts capable of supporting the continuous circulation of Orthobunyavirus.

Quantifying heterogeneities in arbovirus transmission: Description of the rationale and methodology for a prospective longitudinal study of dengue and Zika virus transmission in Iquitos, Peru (2014-2019).

Current knowledge of dengue virus (DENV) transmission provides only a partial understanding of a complex and dynamic system yielding a public health track record that has more failures than successes. An important part of the problem is that the foundation for contemporary interventions includes a series of longstanding, but untested, assumptions based on a relatively small portion of the human population; i.e., people who are convenient to study because they manifest clinically apparent disease. Approaching dengue from the perspective of people with overt illness has produced an extensive body of useful literature. It has not, however, fully embraced heterogeneities in virus transmission dynamics that are increasingly recognized as key information still missing in the struggle to control the most important insect-transmitted viral infection of humans. Only in the last 20 years have there been significant efforts to carry out comprehensive longitudinal dengue studies. This manuscript provides the rationale and comprehensive, integrated description of the methodology for a five-year longitudinal cohort study based in the tropical city of Iquitos, in the heart of the Peruvian Amazon. Primary data collection for this study was completed in 2019. Although some manuscripts have been published to date, our principal objective here is to support subsequent publications by describing in detail the structure, methodology, and significance of a specific research program. Our project was designed to study people across the entire continuum of disease, with the ultimate goal of quantifying heterogeneities in human variables that affect DENV transmission dynamics and prevention. Because our study design is applicable to other Aedes transmitted viruses, we used it to gain insights into Zika virus (ZIKV) transmission when during the project period ZIKV was introduced and circulated in Iquitos. Our prospective contact cluster investigation design was initiated by detecttion of a person with a symptomatic DENV infection and then followed that person's immediate contacts. This allowed us to monitor individuals at high risk of DENV infection, including people with clinically inapparent and mild infections that are otherwise difficult to detect. We aimed to fill knowledge gaps by defining the contribution to DENV transmission dynamics of (1) the understudied majority of DENV-infected people with inapparent and mild infections and (2) epidemiological, entomological, and socio-behavioral sources of heterogeneity. By accounting for factors underlying variation in each person's contribution to transmission we sought to better determine the type and extent of effort needed to better prevent virus transmission and disease.

The Aedes aegypti peritrophic matrix controls arbovirus vector competence through HPx1, a heme-induced peroxidase.

Aedes aegypti mosquitoes are the main vectors of arboviruses. The peritrophic matrix (PM) is an extracellular layer that surrounds the blood bolus. It acts as an immune barrier that prevents direct contact of bacteria with midgut epithelial cells during blood digestion. Here, we describe a heme-dependent peroxidase, hereafter referred to as heme peroxidase 1 (HPx1). HPx1 promotes PM assembly and antioxidant ability, modulating vector competence. Mechanistically, the heme presence in a blood meal induces HPx1 transcriptional activation mediated by the E75 transcription factor. HPx1 knockdown increases midgut reactive oxygen species (ROS) production by the DUOX NADPH oxidase. Elevated ROS levels reduce microbiota growth while enhancing epithelial mitosis, a response to tissue damage. However, simultaneous HPx1 and DUOX silencing was not able to rescue bacterial population growth, as explained by increased expression of antimicrobial peptides (AMPs), which occurred only after double knockdown. This result revealed hierarchical activation of ROS and AMPs to control microbiota. HPx1 knockdown produced a 100-fold decrease in Zika and dengue 2 midgut infection, demonstrating the essential role of the mosquito PM in the modulation of arbovirus vector competence. Our data show that the PM connects blood digestion to midgut immunological sensing of the microbiota and viral infections.

Dengue, chikungunya, and Zika virus infections in Latin America and the Caribbean: a systematic review

[ABSTRACT]. Objectives. To characterize the distribution profile of dengue, chikungunya, and Zika virus infections in Latin America and the Caribbean and to identify possible factors associated with the risk of dissemination and severity of these arboviruses. Methods. The protocol of this review was registered on the PROSPERO platform. Searches were carried out in the following databases: Virtual Health Library, MEDLINE/PubMed, and Embase. The search terms were: Zika virus, Zika virus infection, dengue, dengue virus, chikungunya virus, chikungunya fever, epidemiology, observational study, Latin America, and Caribbean region. Studies that addressed the distribution of these arboviruses and the risk factors associated with dengue, Zika virus disease, and chikungunya, published between January 2000 and August 2020 in English, Portuguese, and Spanish, were included. Results. Of 95 studies included, 70 identified risk factors, clinical manifestations, and outcomes for arbovirus infections and 25 described complications and/or deaths. The highest frequency of confirmed cases was for dengue. Brazil reported most cases of the three arboviruses in the period analyzed. Environmental and socio- economic factors facilitated the proliferation and adaptation of vectors, and host-related factors were reported to aggravate dengue. Most deaths were due to chikungunya, Zika virus disease caused most neurological alterations, and dengue resulted in greater morbidity leading to more frequent hospitalization. Conclusions. The review provides a broad view of the three arboviruses and the intrinsic aspects of infections, and highlights the factors that influence the spread of these viruses in the populations studied.

[RESUMEN]. Objetivos. Caracterizar el perfil de distribución de infecciones por dengue, chikungunya y el virus de Zika en América Latina y el Caribe, y determinar posibles factores relacionados con el riesgo de propagación y gravedad de estas arbovirosis. Métodos. Se registró el protocolo de esta revisión en la plataforma PROSPERO. Se realizaron búsquedas en las siguientes bases de datos: Virtual Health Library, MEDLINE/PubMed y Embase. Los términos de búsqueda fueron: “zika virus” [virus del Zika], “zika virus infection” [infección por el virus del Zika], “dengue”, “den- gue virus” [virus del dengue], “chikungunya virus” [virus del chikunguña], “chikungunya fever” [fiebre de chikunguña], “epidemiology” [epidemiología], “observational study” [estudio observacional], “Latin America” [América Latina] y “Caribbean región” [Caribe]. Se incluyeron estudios que abordaban la distribución de estas arbovirosis y los factores de riesgo asociados con el dengue, la enfermedad por el virus del Zika y el chikunguña, publicados entre enero del 2000 y agosto del 2020 en español, inglés y portugués. Resultados. De los 95 estudios incluidos, 70 establecieron factores de riesgo, manifestaciones clínicas y resultados de las infecciones por arbovirus y 25 describieron complicaciones o muertes. La mayor frecuen- cia de casos confirmados fue del dengue. Brasil notificó la mayoría de los casos de infección por los tres arbovirus en el período analizado. Los factores ambientales y socioeconómicos facilitaron la proliferación y adaptación de los vectores, y se notificó que los factores relacionados con el huésped agravaban el dengue. El chikunguña causó la mayor parte de las muertes, la enfermedad por el virus del Zika causó la mayor parte de las alteraciones neurológicas y el dengue fue responsable de una mayor morbilidad, lo que llevó a una hospitalización más frecuente. Conclusiones. Esta revisión ofrece un panorama de las tres arbovirosis y de los aspectos intrínsecos de las infecciones, y pone de relieve los factores que influyen en la propagación de estos virus en las poblaciones estudiadas.

[RESUMO]. Objetivos. Descrever a distribuição das arboviroses causadas pelo vírus da dengue, zika e chikungunya na América Latina e no Caribe e identificar possíveis fatores associados ao potencial de disseminação e à grav- idade dessas infecções. Métodos. O protocolo desta revisão sistemática foi registado na plataforma PROSPERO. Foram realizadas buscas nas bases de dados Biblioteca Virtual em Saúde, MEDLINE/PubMed e Embase. Os termos de busca foram: vírus zika, infecção pelo vírus zika, dengue, vírus da dengue, vírus chikungunya, febre chikungunya, epidemiologia, estudo observacional, América Latina e região do Caribe. Foram selecionados estudos publicados em inglês, português e espanhol, entre janeiro de 2000 e agosto de 2020, que tratavam da dis- tribuição desses arbovírus e de fatores de risco associados à dengue, à infecção pelo vírus zika e à febre chikungunya. Resultados. Dos 95 estudos selecionados, 70 descreveram fatores de risco, manifestações clínicas e des- fechos das arboviroses e 25 destacaram as complicações e/ou mortes. Houve uma maior taxa de casos confirmados de dengue. O Brasil foi o país onde se registrou a maioria dos casos dessas três arboviroses no período analisado. Fatores ambientais e socioeconômicos facilitaram a proliferação e a adaptação dos vetores dos arbovírus e fatores próprios do hospedeiro são determinantes na gravidade da dengue. As mortes ocorreram principalmente nos casos de febre chikungunya, as manifestações neurológicas foram mais comuns na infecção pelo vírus zika e a dengue resultou em maior morbidade e internação hospitalar. Conclusões. Esta revisão sistemática oferece um panorama destas três arboviroses e de suas peculiari- dades destacando os fatores que influenciam a disseminação destes arbovírus nas populações estudadas.

Arboviruses in Mammals in the Neotropics: A Systematic Review to Strengthen Epidemiological Monitoring Strategies and Conservation Medicine.

Arthropod-borne viruses (arboviruses) are a diverse group of ribonucleic acid (RNA) viruses, with the exception of African swine fever virus, that are transmitted by hematophagous arthropods to a vertebrate host. They are the important cause of many diseases due to their ability to spread in different environments and their diversity of vectors. Currently, there is no information on the geographical distribution of the diseases because the routes of transmission and the mammals (wild or domestic) that act as potential hosts are poorly documented or unknown. We conducted a systematic review from 1967 to 2021 to identify the diversity of arboviruses, the areas, and taxonomic groups that have been monitored, the prevalence of positive records, and the associated risk factors. We identified forty-three arboviruses in nine mammalian orders distributed in eleven countries. In Brazil, the order primates harbor the highest number of arbovirus records. The three most recorded arboviruses were Venezuelan equine encephalitis, Saint Louis encephalitis and West Nile virus. Serum is the most used sample to obtain arbovirus records. Deforestation is identified as the main risk factor for arbovirus transmission between different species and environments (an odds ratio of 1.46 with a 95% confidence interval: 1.34-1.59). The results show an increase in the sampling effort over the years in the neotropical region. Despite the importance of arboviruses for public health, little is known about the interaction of arboviruses, their hosts, and vectors, as some countries and mammalian orders have not yet been monitored. Long-term and constant monitoring allows focusing research on the analysis of the interrelationships and characteristics of each component animal, human, and their environment to understand the dynamics of the diseases and guide epidemiological surveillance and vector control programs. The biodiversity of the Neotropics should be considered to support epidemiological monitoring strategies.

Spatiotemporal distribution of vector mosquito species and areas at risk for arbovirus transmission in Maricopa County, Arizona.

Mosquito-borne diseases are a major global public health concern and mosquito surveillance systems are essential for the implementation of effective mosquito control strategies. The objective of our study is to determine the spatiotemporal distribution of vector mosquito species in Maricopa County, AZ from 2011 to 2021, and to identify the hotspot areas for West Nile virus (WNV) and St. Louis Encephalitis virus (SLEV) transmission in 2021. The Maricopa County Mosquito Control surveillance system utilizes BG-Sentinel and EVS-CDC traps throughout the entire urban and suburban areas of the county. We estimated specific mosquito species relative abundance per unit area using the Kernel density estimator in ArcGIS 10.2. We calculated the distance between all traps in the surveillance system and created a 4 km buffer radius around each trap to calculate the extent to which each trap deviated from the mean number of Culex quinquefasciatus and Culex tarsalis collected in 2021. Our results show that vector mosquito species are widely distributed and abundant in the urban areas of Maricopa County. A total of 691,170Cx. quinquefasciatus, 542,733 Cx. tarsalis, and 292,305 Aedes aegypti were collected from 2011 to 2022. The relative abundance of Ae. aegypti was highly seasonal peaking in the third and fourth quarters of the year. Culex quinquefasciatus, on the other hand, was abundant throughout the year with several regions consistently yielding high numbers of mosquitoes. Culex tarsalis was abundant but it only reached high numbers in well-defined areas near irrigated landscapes. We also detected high levels of heterogeneity in the risk of WNV and SLEV transmission to humans disregarding traps geographical proximity. The well-defined species-specific spatiotemporal and geographical patterns found in this study can be used to inform vector control operations.

Diel activity patterns of vector mosquito species in the urban environment: Implications for vector control strategies.

Mathematical models have been widely used to study the population dynamics of mosquitoes as well as to test and validate the effectiveness of arbovirus outbreak responses and mosquito control strategies. The objective of this study is to assess the diel activity of mosquitoes in Miami-Dade, Florida, and Brownsville, Texas, the most affected areas during the Zika outbreak in 2016-2017, and to evaluate the effectiveness of simulated adulticide treatments on local mosquito populations. To assess variations in the diel activity patterns, mosquitoes were collected hourly for 96 hours once a month from May through November 2019 in Miami-Dade County, Florida, and Brownsville, Texas. We then performed a PERMANOVA followed by a SIMPER analysis to assess whether the abundance and species richness significantly varies at different hours of the day. Finally, we used a mathematical model to simulate the population dynamics of 5 mosquito vector species and evaluate the effectiveness of the simulated adulticide applications. A total of 14,502 mosquitoes comprising 17 species were collected in Brownsville and 10,948 mosquitoes comprising 19 species were collected in Miami-Dade County. Aedes aegypti was the most common mosquito species collected every hour in both cities and peaking in abundance in the morning and the evening. Our modeling results indicate that the effectiveness of adulticide applications varied greatly depending on the hour of the treatment. In both study locations, 9 PM was the best time for adulticide applications targeting all mosquito vector species; mornings/afternoons (9 AM- 5 PM) yielded low effectiveness, especially for Culex species, while at night (12 AM- 6 AM) the effectiveness was particularly low for Aedes species. Our results indicate that the timing of adulticide spraying interventions should be carefully considered by local authorities based on the ecology of the target mosquito species in the focus area.

Mosquito vector competence for dengue is modulated by insect-specific viruses.

Aedes aegypti and A. albopictus mosquitoes are the main vectors for dengue virus (DENV) and other arboviruses, including Zika virus (ZIKV). Understanding the factors that affect transmission of arboviruses from mosquitoes to humans is a priority because it could inform public health and targeted interventions. Reasoning that interactions among viruses in the vector insect might affect transmission, we analysed the viromes of 815 urban Aedes mosquitoes collected from 12 countries worldwide. Two mosquito-specific viruses, Phasi Charoen-like virus (PCLV) and Humaita Tubiacanga virus (HTV), were the most abundant in A. aegypti worldwide. Spatiotemporal analyses of virus circulation in an endemic urban area revealed a 200% increase in chances of having DENV in wild A. aegypti mosquitoes when both HTV and PCLV were present. Using a mouse model in the laboratory, we showed that the presence of HTV and PCLV increased the ability of mosquitoes to transmit DENV and ZIKV to a vertebrate host. By transcriptomic analysis, we found that in DENV-infected mosquitoes, HTV and PCLV block the downregulation of histone H4, which we identify as an important proviral host factor in vivo.

Culex Y Virus: A Native Virus of Culex Species Characterized In Vivo.

Mosquitoes are vectors of various pathogens that cause diseases in humans and animals. To prevent the outbreak of mosquito-borne diseases, it is essential to control vector populations, as treatment or vaccination for mosquito-borne diseases are often unavailable. Insect-specific viruses (ISVs) have previously been described as being potentially helpful against arboviral disease outbreaks. In this study, we present the first in vivo characterization of the ISV Culex Y virus (CYV). CYV was first isolated from free-living Culex pipiens mosquitoes in 2010; then, it was found in several mosquito cell lines in a further study in 2018. For mammalian cells, we were able to confirm that CYV does not replicate as it was previously described. Additionally, we found that CYV does not replicate in honey bees or locusts. However, we detected replication in the Culex pipiens biotype molestus, Aedes albopictus, and Drosophila melanogaster, thus indicating dipteran specificity. We detected significantly higher mortality in Culex pipiens biotype molestus males and Drosophila melanogaster, but not in Aedes albopictus and female Culex pipiens biotype molestus. CYV could not be transmitted transovarially to offspring, but we detected venereal transmission as well as CYV in mosquitos' saliva, indicating that an oral route of infection would also be possible. CYV's dipteran specificity, transmission routes, and killing effect with respect to Culex males may be used as powerful tools with which to destabilize arbovirus vector populations in the future.

Seasonal changes in the diversity, host preferences and infectivity of mosquitoes in two arbovirus-endemic regions of Costa Rica.

BACKGROUND: Mosquitoes are vectors of various arboviruses belonging to the genera Alphavirus and Flavivirus, and Costa Rica is endemic to several of them. The aim of this study was to describe and analyze the community structure of such vectors in Costa Rica. METHODS: Sampling was performed in two different coastal locations of Costa Rica with evidence of arboviral activity during rainy and dry seasons. Encephalitis vector surveillance traps, CDC female gravid traps and ovitraps were used. Detection of several arboviruses by Pan-Alpha and Pan-Flavi PCR was attempted. Blood meals were also identified. The Normalized Difference Vegetation Index (NDVI) was estimated for each area during the rainy and dry seasons. The Chao2 values for abundance and Shannon index for species diversity were also estimated. RESULTS: A total of 1802 adult mosquitoes belonging to 55 species were captured, among which Culex quinquefasciatus was the most caught species. The differences in NDVI were higher between seasons and between regions, yielding lower Chao-Sørensen similarity index values. Venezuelan equine encephalitis virus, West Nile virus and Madariaga virus were not detected at all, and dengue virus and Zika virus were detected in two separate Cx. quinquefasciatus specimens. The primary blood-meal sources were chickens (60%) and humans (27.5%). Both sampled areas were found to have different seasonal dynamics and population turnover, as reflected in the Chao2 species richness estimation values and Shannon diversity index. CONCLUSION: Seasonal patterns in mosquito community dynamics in coastal areas of Costa Rica have strong differences despite a geographical proximity. The NDVI influences mosquito diversity at the regional scale more than at the local scale. However, year-long continuous sampling is required to better understand local dynamics.

Linking mathematical models and trap data to infer the proliferation, abundance, and control of Aedes aegypti.

Aedes aegypti is one of the most dominant mosquito species in the urban areas of Miami-Dade County, Florida, and is responsible for the local arbovirus transmissions. Since August 2016, mosquito traps have been placed throughout the county to improve surveillance and guide mosquito control and arbovirus outbreak response. In this paper, we develop a deterministic mosquito population model, estimate model parameters by using local entomological and temperature data, and use the model to calibrate the mosquito trap data from 2017 to 2019. We further use the model to compare the Ae. aegypti population and evaluate the impact of rainfall intensity in different urban built environments. Our results show that rainfall affects the breeding sites and the abundance of Ae. aegypti more significantly in tourist areas than in residential places. In addition, we apply the model to quantitatively assess the effectiveness of vector control strategies in Miami-Dade County.

The investigation of Culicoides (Diptera: Ceratopogonidae) species and Bluetongue virus and Schmallenberg virus in Northwest Türkiye.

Culicoides biting midges (Diptera: Ceratopogonidae) act as mechanical and biological vectors of arboviruses and are crucial in the global spread of these viruses. This study investigated the diversity of distribution of Culicoides species and the presence of Bluetongue virus (BTV) and Schmallenberg virus (SBV) in Tekirdag province in Northwest Türkiye. The fourteen Culicoides species, such as Culicoides newsteadi, Culicoides schultzei, Culicoides nubeculosus comp., Culicoides punctatus, Culicoides circumscriptus, Culicoides obsoletus comp., Culicoides gejgelensis, Culicoides festivipennis, Culicoides longipennis, Culicoides spp., Culicoides pulicaris, Culicoides picturatus, Culicoides odiatus, Culicoides kurensis, and Culicoides flavipulicaris, were detected. Culicoides newsteadi, C. odiatus, and C. pulicaris were the most abundant species. Phylogenetic analyses of Culicoides species' ITS-1 gene region were performed. A pool of C. festivipennis was positive for SBV RNA, while the BTV genomic materials was not found in the qPCR analysis. This is the first report of the presence/detection of SBV in Culicoides species in Türkiye. The survey of bioecological and epizootiological aspects of vector species is essential in implementing effective control measures for arboviral infections.

Aedes albopictus (Skuse) dispersion in Havana City, Cuba, 1995-2018.

Various arboviruses are transmitted to humans by mosquitoes, particularly Aedes aegypti and Aedes albopictus, two invasive and frequently sympatric species. The objective of this study was to evaluate the dispersion and the behavior of Ae. albopictus in relation to houses and its association with other mosquitoes in the province of Havana, Cuba. All water-containing deposits in the houses or vacant lots in urban and peri­urban municipalities of the province of Havana were sampled during the two study periods: 1995-1999 and 2010-2018. The following patterns in the presence of Ae. albopictus in the study area were observed: a persistent absence of Ae. albopictus in one of the municipalities; a rapid dispersion in the second period, staring from the absence of vector in the first period, in tow other municipalities; and a sustained decrease in the dispersion of Ae.albopictus in two other municipalities. The peripheral municipalities noted the highest presence of Ae. albopictus, but few associations with other mosquitoes. However, overall, we found an increase in this association when comparing the period 2010-2018 with the first period. Ae. albopictus was present in 8% (2016) to 21.5% (2013) inside the houses with an average of 15%, which evidences an initial domiciliation of the species. The results obtained in this work show an initiation of domiciliation of Ae. albopictus in the urban area of the province of Havana. This is important to alert the National Control Program to strengthen the entomological monitoring of Ae. albopictus, and not only Ae. aegypti. The follow-up of this domiciliation is important to guide control efforts, knowing its role as a vector of different arboviruses.

A Brief History of the Discovery of RNA-Mediated Antiviral Immune Defenses in Vector Mosquitos.

Arthropod-borne viruses (arboviruses) persist in a natural cycle that includes infections of humans or other vertebrates and transmission between vertebrates by infected arthropods, most commonly mosquitos. Arboviruses can cause serious, sometimes fatal diseases in humans and other vertebrates but cause little pathology in their mosquito vectors. Knowledge of the interactions between mosquito vectors and the arboviruses that they transmit is an important facet of developing schemes to control transmission. Mosquito innate immune responses to virus infection modulate virus replication in the vector, and understanding the components and mechanisms of the immune response could lead to improved methods for interrupting the transmission cycle. The most important aspect of mosquito antiviral defense is the exogenous small interfering RNA (exo-siRNA) pathway, one arm of the RNA interference (RNAi) silencing response. Our research as well as that of many other groups over the past 25 years to define this pathway are reviewed here. A more recently recognized but less well-understood RNA-mediated mosquito defense against arbovirus infections, the PIWI-interacting RNA (piRNA) pathway, is also described.

Anopheles stephensi in Africa: vector control opportunities for cobreeding An. stephensi and Aedes arbovirus vectors.

Anopheles stephensi is an urban malaria vector native in some Asian countries and recently emerged in Africa as an invasive vector competent in transmitting Plasmodium falciparum and P. vivax. The coexistence of An. stephensi and Aedes arboviral vectors offers an optimal opportunity for successful integrated vector management with limited resources.

Risque de transmission de certains arbovirus à travers le don de sang à Bamako / Risk of transmission of certain arbovirus through blood donation in the city of Bamako

Introduction. Au Mali, le dépistage de certains virus tels que la dengue, Zika et la fièvre de la vallée du Rift n'est pas systématique au centre national de transfusion sanguine (CNTS). Le risque peut être considérable en raison de leurs courtes périodes de virémie asymptomatique dans la population dont l'incidence est variable et parfois extrêmement élevée. Cette étude avait pour objectif d'explorer la possibilité de transmission de certains arbovirus à travers le don de sang au CNTS de Bamako. Méthodes. Il s'agissait d'une étude transversale, de juillet 2019 à juin 2020 à Bamako. Au total deux cents (200) donneurs de sang du CNTS ont été inclus. Les examens ont été réalisés au Centre d'Infectiologie Charles Mérieux (CICM) de Bamako avec le dépistage du génome des virus responsables de la Dengue, de la fièvre de la Vallée du Rift, et du Zika à l'aide de la technique de la RT-PCR en temps réel. Le Test de Dépistage Rapide (TDR) a été utilisé pour la détection des anticorps IgG et IgM spécifiques de la Dengue. Résultats. Le sexe masculin représente 84% (168/200). Le TDR a détecté 4,5% (9/200) de Dengue IgG positifs et aucun cas de Dengue IgM positif. La technique de RT-PCR n'a détecté aucun des trois virus. Conclusion. Cette étude prouve que le risque de transmission de certains arbovirus à travers le don de sang existe, mais il semble être minime au CNTS de Bamako

Background. In Mali, screening for certain viruses such as dengue, Zika, and Rift Valley fever is not systematic at the national blood transfusion center (CNTS). The risk can be considerable due to their short periods of asymptomatic viremia in the population with variable and sometimes extremely high incidence. The objective of this study was to explore the possibility of transmission of certain arboviruses through blood donation at the CNTS of Bamako. Methods. This was a cross-sectional study, from July 2019 to June 2020 in Bamako. A total of two hundred (200) blood donors from the CNTS were included. The examinations were performed at the Centre d'Infectiologie Charles Mérieux (CICM) in Bamako with the screening of the genome of viruses responsible for Dengue, Rift Valley fever, and Zika using the real-time RT-PCR technique. The Rapid Screening Test (RST) was used for the detection of Dengue-specific IgG and IgM antibodies. Results. Male sex represented 84% (168/200). The RDT detected 4.5% (9/200) of IgG positive Dengue and no IgM positive Dengue cases. The RT-PCR technique did not detect any of the three viruses. Conclusion. This study proves that the risk of transmission of certain arboviruses through blood donation exists, but it seems to be minimal at the CNTS of Bamako.

Early Genomic Surveillance and Phylogeographic Analysis of Getah Virus, a Reemerging Arbovirus, in Livestock in China.

Getah virus (GETV) mainly causes disease in livestock and may pose an epidemic risk due to its expanding host range and the potential of long-distance dispersal through animal trade. Here, we used metagenomic next-generation sequencing (mNGS) to identify GETV as the pathogen responsible for reemerging swine disease in China and subsequently estimated key epidemiological parameters using phylodynamic and spatially-explicit phylogeographic approaches. The GETV isolates were able to replicate in a variety of cell lines, including human cells, and showed high pathogenicity in a mouse model, suggesting the potential for more mammal hosts. We obtained 16 complete genomes and 79 E2 gene sequences from viral strains collected in China from 2016 to 2021 through large-scale surveillance among livestock, pets, and mosquitoes. Our phylogenetic analysis revealed that three major GETV lineages are responsible for the current epidemic in livestock in China. We identified three potential positively selected sites and mutations of interest in E2, which may impact the transmissibility and pathogenicity of the virus. Phylodynamic inference of the GETV demographic dynamics identified an association between livestock meat consumption and the evolution of viral genetic diversity. Finally, phylogeographic reconstruction of GETV dispersal indicated that the sampled lineages have preferentially circulated within areas associated with relatively higher mean annual temperature and pig population density. Our results highlight the importance of continuous surveillance of GETV among livestock in southern Chinese regions associated with relatively high temperatures. IMPORTANCE Although livestock is known to be the primary reservoir of Getah virus (GETV) in Asian countries, where identification is largely based on serology, the evolutionary history and spatial epidemiology of GETV in these regions remain largely unknown. Through our sequencing efforts, we provided robust support for lineage delineation of GETV and identified three major lineages that are responsible for the current epidemic in livestock in China. We further analyzed genomic and epidemiological data to reconstruct the recent demographic and dispersal history of GETV in domestic animals in China and to explore the impact of environmental factors on its genetic diversity and its diffusion. Notably, except for livestock meat consumption, other pig-related factors such as the evolution of live pig transport and pork production do not show a significant association with the evolution of viral genetic diversity, pointing out that further studies should investigate the potential contribution of other host species to the GETV outbreak. Our analysis of GETV demonstrates the need for wider animal species surveillance and provides a baseline for future studies of the molecular epidemiology and early warning of emerging arboviruses in China.

Anopheles albimanus is a Potential Alphavirus Vector in the Americas.

Despite its ecological flexibility and geographical co-occurrence with human pathogens, little is known about the ability of Anopheles albimanus to transmit arboviruses. To address this gap, we challenged An. albimanus females with four alphaviruses and one flavivirus and monitored the progression of infections. We found this species is an efficient vector of the alphaviruses Mayaro virus, O'nyong-nyong virus, and Sindbis virus, although the latter two do not currently exist in its habitat range. An. albimanus was able to become infected with Chikungunya virus, but virus dissemination was rare (indicating the presence of a midgut escape barrier), and no mosquito transmitted. Mayaro virus rapidly established disseminated infections in An. albimanus females and was detected in the saliva of a substantial proportion of infected mosquitoes. Consistent with previous work in other anophelines, we find that An. albimanus is refractory to infection with flaviviruses, a phenotype that did not depend on midgut-specific barriers. Our work demonstrates that An. albimanus may be a vector of neglected emerging human pathogens and adds to recent evidence that anophelines are competent vectors for diverse arboviruses.