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The Orthobunyavirus oropoucheense species encompasses a group of arthropod‐borne zoonotic viruses transmitted by biting midges to animals including humans. Several large‐scale human outbreaks caused by the prototype member of this species, Oropouche virus (OROV) have been documented since the 1970s and were primarily confined to the Amazon basin. However, since 2022, more widespread OROV outbreaks have been unfolding in Brazil and across South America, with cases exported to Cuba, Italy, Spain, USA and Germany. In Brazil, the virus has reached and established communitary transmission in all geographic areas of the country. We isolated, characterized the cytopathic effect and recovered the full genome of two OROV isolates from the 2022–24 outbreak detected in patients from the Pernambuco state. Phylogenetic data supports a direct introduction from the Amazonas state, the epicenter of the epidemics in the country. As case counts accumulate in the state mounting evidence is supporting the establishiment of sustained transmission chains. Continued studies are critical to understand the transmission cycle in this region, including the most important vectors and reservoirs, to appropriately deploy control measures. [ABSTRACT FROM AUTHOR]

Ticks can transmit many pathogens, including arboviruses, to their vertebrate hosts. Arboviruses must overcome or evade defense mechanisms during their passage from the tick gut to the hemolymph, salivary glands, and the feeding site in the host skin. This review summarizes current knowledge of defense mechanisms in specific tick tissues and at the feeding site in the host skin. We discuss the possible roles of these defense mechanisms in viral infection and transmission. The responses of tick salivary proteins to arbovirus infection are also discussed. This review provides information that may help accelerate research on virus–tick interactions. [ABSTRACT FROM AUTHOR]

Insects are the host or vector of diverse viruses including those that infect vertebrates, plants, and fungi. Insect viruses reside inside their insect hosts and are vertically transmitted from parent to offspring. The insect virus–host relationship is intricate, as these viruses can impact various aspects of insect biology, such as development, reproduction, sex ratios, and immunity. Arthropod‐borne viruses (arboviruses) that cause substantial global health or agricultural problems can also be vertically transmitted to insect vector progeny. Multiple infections with insect viruses and arboviruses are common in nature. Such coinfections involve complex interactions, including synergism, dependence, and antagonism. Recent studies have shed light on the influence of insect viruses on the competence of insect vectors for arboviruses. In this review, we focus on the biological effects of insect viruses on the transmission of arboviruses by insects. We also discuss the potential mechanisms by which insect viruses affect the ability of hosts to transmit arboviruses, as well as potential strategies for disease control through manipulation of insect viruses. Analyses of the interactions among insect vectors, insect viruses and arboviruses will provide new opportunities for development of innovative strategies to control arbovirus transmission. [ABSTRACT FROM AUTHOR]

The World Health Organization classified Crimean–Congo hemorrhagic fever (CCHF) as a high‐priority infectious disease and emphasized the performance of research studies and product development against it. Little information is available about the immune response due to natural CCHF virus (CCHFV) infection in humans. Here, we investigated the persistence of IgG and neutralizing antibodies in serum samples collected from 61 Iranian CCHF survivors with various time points after recovery (<12, 12−60, and >60 months after disease). The ELISA results showed IgG seropositivity in all samples while a pseudotyped based neutralization assay findings revealed the presence of neutralizing antibody in 29 samples (46.77%). For both IgG and neutralizing antibodies, a decreasing trend of titer was observed with the increase in the time after recovery. Not only the mean titer of IgG (772.80 U/mL) was higher than mean neutralizing antibody (25.64) but also the IgG persistence was longer. In conclusion, our findings provide valuable information about the long‐term persistence of humoral immune response in CCHF survivors indicating that IgG antibody can be detected at least 8 years after recovery and low titers of neutralizing antibody can be detected in CCHF survivors. [ABSTRACT FROM AUTHOR]

The increase of environmental temperature due to current global warming is not only favouring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which the effects of developmental temperatures extend across developmental stages and their inter‐stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector, to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome and Wolbachia prevalence in laboratory‐reared populations originally collected from either temperate or tropical regions. We show that hatchability, larval and pupal viability and developmental speed are strongly influenced by temperature, and these effects extend to wing length, body mass, longevity and content of water, protein and lipids in adults in a population‐specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Wolbachia density was generally lower in adult mosquitoes reared at 18°C than at other tested temperatures, and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450 and heat shock proteins) in mosquitoes reared at both 18 and 32°C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32°C, and the absence of isomorphy in the relationship between developmental stages and temperature in the laboratory population deriving from larvae collected in northern Italy. Altogether, these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact. [ABSTRACT FROM AUTHOR]

Arthropod‐borne viruses (arboviruses) count among emerging infections, which represent a major challenge for transfusion safety worldwide. To assess the risk of arboviruses‐transmission by transfusion (ATT), we performed a survey to evaluate the potential threat for transfusion safety. Samples were retrospectively and randomly collected from donors who donated during the peak of dengue incidence in Cordoba (years: 2016 and 2019–2022). A cost‐efficient strategy for molecular screening was implemented with a nucleic acid test (NAT) configured with Flavivirus and Alphavirus‐universal degenerated primers targeting conserved gene regions. Besides, we evaluated the neutralizing antibody (NAb) prevalence by plaque reduction neutralization test (PRNT). A total of 1438 samples were collected. Among the NAT‐screened samples, one resulted positive for Flavivirus detection. Subsequent sequencing of the PCR product revealed Saint Louis Encephalitis Virus (SLEV) infection (GeneBank accession number OR236721). NAb prevalence was 2.95% for anti‐Dengue, 9.94% anti‐SLEV, 1.09% anti‐West Nile Virus, and 0% anti‐Chikungunya. One of the NAb‐positive samples also resulted positive for IgM against SLEV but negative by ARN detection. This is the first haemovigilance study developed in Argentina that evaluates the potential risk of ATT and the first research to determine the prevalence of NAb against Flavivirus through PNRT to avoid possible cross‐reactions between Ab against Flavivirus. Herein, the finding of one SLEV‐viremic donor and the detection of anti‐SLEV IgM in a different donor demonstrated a potential threat for transfusion safety and emphasized the need for increased vigilance and proactive measures to ensure the safety of blood supplies. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is the most significant arbovirus in the United States in terms of both morbidity and mortality. West Nile exists in a complex transmission cycle between avian hosts and the arthropod vector, Culex spp. mosquitoes. Human spillover events occur when humans are bitten by an infected mosquito and predicting these rates of infection and therefore the risk to humans may be associated with fluctuations in environmental conditions. In this study, we evaluate the hydrological and meteorological drivers associated with mosquito biology and viral development to determine if these associations can be used to forecast seasonal mosquito infection rates with WNV in the Coachella Valley of California. We developed and tested a spatially resolved ensemble forecast model of the WNV mosquito infection rate in the Coachella Valley using 17 years of mosquito surveillance data and North American Land Data Assimilation System‐2 environmental data. Our multi‐model inference system indicated that the combination of a cooler and dryer winter, followed by a wetter and warmer spring, and a cooler than normal summer was most predictive of the prevalence of West Nile positive mosquitoes in the Coachella Valley. The ability to make accurate early season predictions of West Nile risk has the potential to allow local abatement districts and public health entities to implement early season interventions such as targeted adulticiding and public health messaging before human transmission occurs. Such early and targeted interventions could better mitigate the risk of WNV to humans. Plain Language Summary: West Nile virus (WNV) is the most significant arbovirus in the United States and is transmitted seasonally by mosquitoes. Humans are most at risk when they are in close proximity to infected mosquitoes. Predicting the risk to humans is not straightforward. In this study, we use deviations in climate associated with mosquito biology and viral development to forecast seasonal West Nile risk in the Coachella Valley of California. We developed a statistical model of WNV transmission in the Coachella Valley using 17 years of mosquito surveillance data and environmental data. Our model indicated that the combination of a cooler and dryer winter followed by a wetter and warmer spring and a cooler than normal summer was the combination of environmental events most associated with West Nile positive mosquitoes in the Coachella Valley. The ability to make accurate early season predictions of West Nile risk could assist local public health entities implement early season interventions to better mitigate the risk of WNV to humans in the Coachella Valley. Key Points: Environmentally informed West Nile virus (WNV) forecast modelOur forecast shows that a dry, cool winter, followed by a wet, warm spring, and a cool summer promotes WNVEarly season forecasts are a potential decision tool to inform public health and mosquito abatement intervention [ABSTRACT FROM AUTHOR]

Background: Brazil has a high prevalence of arboviruses, especially Dengue (DENV), Zika (ZKV), and Chikungunya (CHKV). Objectives: To study the risk of DENV, ZKV, and CHKV transmission by blood components in the haematopoietic stem cell transplantation (HSCT) population. Methods: Prospective cohort of HSCT recipients and donors performed at the Hospital das Clinicas da FMUSP, São Paulo‐Brazil. Patients were evaluated by serology and RT‐PCR for DENV, ZKV, and CHKV pre‐transplantation and once a week until neutrophil grafting. In positive cases (positive RT‐PCR and/or serology conversion), an investigation was carried out on the blood components that the patient received to evaluate the possibility of it being transfusion transmitted. Results: A total of 93 patients were included during the study period. The mean age was 52 years with a predominance of males (56.9%). We considered five (5.3%) DENV cases positive by seroconversion in our study. One patient had IgM seroconversion and the other four presented IgG seroconversion to DENV. In the investigation of the blood components, 145 individual samples were analysed. None of the investigated blood components showed a positive RT‐PCR. Conclusion: We observed a low prevalence of DENV, ZKV, and CHKV in HSCT donors and recipients by serology and RT‐PCR, and no case of blood transfusion transmission by RT‐PCR. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) primarily infects birds and mosquitoes but has also caused over 2,000 human deaths, and >50,000 reported human cases in the United States. Expected numbers of WNV neuroinvasive cases for the present were described for the Northeastern United States, using a negative binomial model. Changes in temperature‐based suitability for WNV due to climate change were examined for the next decade using a temperature‐trait model. WNV suitability was generally expected to increase over the next decade due to changes in temperature, but the changes in suitability were generally small. Many, but not all, populous counties in the northeast are already near peak suitability. Several years in a row of low case numbers is consistent with a negative binomial, and should not be interpreted as a change in disease dynamics. Public health budgets need to be prepared for the expected infrequent years with higher‐than‐average cases. Low‐population counties that have not yet had a case are expected to have similar probabilities of having a new case as nearby low‐population counties with cases, as these absences are consistent with a single statistical distribution and random chance. Plain Language Summary: West Nile virus (WNV) is a virus spread to humans by mosquitoes that had previously bitten an infected animal, usually a bird. We described the chance of one human case over the next one or next 5 years, and the chance of five human cases in any single year over the next 5 years. These chances were broadly similar, and highlight known locations with high numbers of cases of WNV. We also looked at how WNV suitability is expected to change in the near future due to climate change using established methods. We found that suitability for West Nile is expected to increase over most of the northeast, but decrease in some locations. Some locations identified as suitable based on temperature have had relatively few cases. Key Points: Small increases in temperature‐based suitability for West Nile virus (WNV) are expected over most of the northeastern US in the next decadeYears with high and low cases are consistent with the same underlying statistical distributionTemperature‐based suitability for WNV in some of the most populous counties is expected to decrease under climate change [ABSTRACT FROM AUTHOR]

Aedes‐transmitted arboviruses have spread globally due to the spread of Aedes aegypti and Aedes albopictus. Its distribution is associated with human and physical geography. However, these factors have not been quantified in Cameroon. Therefore, the aim was to develop an Ae. albopictus geo‐referenced database to examine the risk factors associated with the vector distribution in Cameroon. Data on the Ae. albopictus presence and absence were collated and mapped from studies in published scientific literature between 2000 and 2020. Publicly available earth observation data were used to assess human geography, land use and climate risk factors related to the vector distribution. A logistic binomial regression was conducted to identify the significant risk factors associated with Ae. albopictus distribution. In total, 111 data points were collated (presence = 87; absence = 24). Different data collection methods and sites hindered the spatiotemporal analysis. An increase of one wet month in a year increased the odds of Ae. albopictus presence by 5.6 times. One unit of peri‐urban area increased the odds by 1.3 times. Using publicly available demographic and environmental data to better understand the key determinants of mosquito distributions may facilitate appropriately targeted public health messages and vector control strategies. [ABSTRACT FROM AUTHOR]

Emerging and endemic mosquito‐borne viruses can be difficult to detect and monitor because they often cause asymptomatic infections in human or vertebrate animals or cause nonspecific febrile illness with a short recovery waiting period. Some of these pathogens circulate into complex cryptic cycles involving several animal species as reservoir or amplifying hosts. Detection of cases in vertebrate hosts can be complemented by entomological surveillance, but this method is not adapted to low infection rates in mosquito populations that typically occur in low or nonendemic areas. We identified West Nile virus circulation in Camargue, a wetland area in South of France, using a cost‐effective xenomonitoring method based on the molecular detection of virus in excreta from trapped mosquitoes. We also succeeded at identifying the mosquito species community on several sampling sites, together with the vertebrate hosts on which they fed prior to being captured using amplicon‐based metabarcoding on mosquito excreta without processing any mosquitoes. Mosquito excreta‐based virus surveillance can complement standard surveillance methods because it is cost‐effective and does not require personnel with a strong background in entomology. This strategy can also be used to noninvasively explore the ecological network underlying arbovirus circulation. [ABSTRACT FROM AUTHOR]

The response to recent dengue outbreaks in Burkina Faso was insecticide‐based, despite poor knowledge of the vector population's susceptibility to the insecticides used. Here, we report on the susceptibility to the main insecticide classes and identify important underlying mechanisms in Aedes aegypti populations in Ouagadougou and Banfora, in 2019 and 2020. Wild Ae. aegypti were tested as adults in WHO bioassays and then screened in real time melting curve qPCR analyses to genotype the F1534C, V1016I, and V410L Aedes kdr mutations. Ae. aegypti showed moderate resistance to 0.1% bendiocarb (80–95% survival post‐exposure), 0.8% Malathion (60–100%), 0.21% pirimiphos‐methyl (75% – 97%), and high resistance to 0.03% deltamethrin (20–70%). PBO pre‐exposure partially restored pyrethroid susceptibility. Genotyping detected high frequency of 1534C allele (0.92) and moderate 1016I (0.1–0.32). The V410L mutation was detected in Burkina Faso for the first time (frequency 0.1–0.36). Mosquitoes surviving 4 h exposure to 0.03% deltamethrin had significantly higher frequencies of the F1534C mutation than dead mosquitoes (0.70 vs. 0.96, p < 0.0001) and mosquitoes surviving 2 ‐ 4 h exposure had a significantly reduced life span. Ae. aegypti from Burkina Faso are resistant to multiple insecticide classes with multiple mechanisms involved, demonstrating the essential role of insecticide resistance monitoring within national dengue control programmes. [ABSTRACT FROM AUTHOR]

The dengue virus nonstructural protein 1 (NS1) is a secreted virulence factor that modulates complement, activates immune cells and alters endothelial barriers. The molecular basis of these events remains incompletely understood. Here we describe a functional high affinity complex formed between NS1 and human high‐density lipoproteins (HDL). Collapse of the soluble NS1 hexamer upon binding to the lipoprotein particle leads to the anchoring of amphipathic NS1 dimeric subunits into the HDL outer layer. The stable complex can be visualized by electron microscopy as a spherical HDL with rod‐shaped NS1 dimers protruding from the surface. We further show that the assembly of NS1‐HDL complexes triggers the production of pro‐inflammatory cytokines in human primary macrophages while NS1 or HDL alone do not. Finally, we detect NS1 in complex with HDL and low‐density lipoprotein (LDL) particles in the plasma of hospitalized dengue patients and observe NS1‐apolipoprotein E‐positive complexes accumulating overtime. The functional reprogramming of endogenous lipoprotein particles by NS1 as a means to exacerbate systemic inflammation during viral infection provides a new paradigm in dengue pathogenesis. Synopsis: The dengue virus NS1 protein forms stable complexes with high‐density lipoprotein (HDL) and low‐density lipoprotein particles, which are detectable in the plasma of severe dengue patients. NS1‐HDL complexes trigger pro‐inflammatory signals in human primary macrophages. DENV NS1 binds human HDL and LDL particles to form stable complexes.Hexameric NS1 fuses with the surface of HDL and disassembles into dimeric rods.NS1‐HDL complexes induce the production of cytokines in human primary macrophages.NS1 forms high molecular weight complexes with apolipoproteins in DENV‐infected patients. [ABSTRACT FROM AUTHOR]

Objective: Evaluate the infectivity of Alphavirus Chikungunya and Mayaro in blood products in plaque forming units (UFP/ml). Background: Arboviruses are responsible for sporadic diseases or epidemics which cause serious public health issues. Due to the high number of asymptomatic infections and high viremia, blood donors may pass on these viruses by transfusion. Methods/Materials: This study used blood bags that would be discarded after evaluation and certification of the absence of infections. The blood products obtained by centrifuging a unit of whole blood were called blood components. All blood bags were infected with viable viruses (previously quantified) compatible with Chikungunya and Mayaro viremia. Results: Blood bags inoculated with both Chikungunya and Mayaro viruses were able to keep infective viruses during the processing of blood products (red blood cell concentrate, platelet concentrate and fresh frozen plasma) and also after the recommended storage for each component, which may infect individuals transfused with those. Conclusion: The results indicate that in order to prevent infections by Mayaro and Chikungunya viruses in blood products it is necessary to stimulate the development and use of diagnostic tests for these pathogens in donated blood. [ABSTRACT FROM AUTHOR]

Due to the concurrent prevalence and increasing risk of coinfection of the clinically important Arboviruses, timely and accurate differential diagnosis is important for clinical management and the epidemiological investigation. A two‐tube multiplex real‐time reverse transcription‐polymerase chain reaction (RT‐PCR) assay for the simultaneous detection of Zika virus (ZIKV), chikungunya virus (CHIKV), dengue virus (DENV), yellow fever virus (YFV), West Nile virus (WNV), and Japanese encephalitis virus (JEV) was developed and optimized with high specificity and sensitivity. The detection limit for all the six viruses could reach as low as five genome equivalent copies and 2.8 × 10−3 tissue culture infectious doses (TCID50) for ZIKV, YFV, CHIKV and 2.8 × 10−2 TCID50 for JEV per reaction, with high accuracy and precision (R2 > 0.99). The coefficient of variation of intra‐assay and inter‐assay for our quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR) assay was low, and the obtained positive rates ad Ct values of this assay were comparable with singleplex commercial kits. Moreover, the multiplex qRT‐PCR assay was able to detect possible co‐infections without competitive inhibition of target viral genomes. In conclusion, our rapid, sensitive, cost‐effective multiplex qRT‐PCR will be of great use for differential diagnosis in a clinical setting and epidemiological investigation during surveillance. Highlights: •A two‐tube multiplex quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR) assay for the simultaneous detection of Zika virus, chikungunya virus, dengue virus, yellow fever virus, West Nile virus, and Japanese encephalitis virus was developed and optimized with high specificity and sensitivity.•The multiplex qRT‐PCR assay was able to detect possible coinfections without competitive inhibition of target viral genomes.•This assay will be of great use for the differential diagnosis in clinical setting and epidemiological investigation during surveillance. [ABSTRACT FROM AUTHOR]

The newly established virus family Phenuiviridae in Bunyavirales harbors viruses infecting three kingdoms of host organisms (animals, plants, and fungi), which is rare in known virus families. Many phenuiviruses are arboviruses and replicate in two distinct hosts (e.g., insects and humans or rice). Multiple phenuivirid species, such as Dabie bandavirus, Rift Valley fever phlebovirus, and Rice stripe tenuivirus, are highly pathogenic to humans, animals, or plants. They impose heavy global burdens on human health, livestock industry, and agriculture and are research hotspots. In recent years the taxonomy of Phenuiviridae has been expanded greatly, and research on phenuiviruses has made significant progress. With these advances, this review drew a novel panorama regarding the biomedical significance, distribution, morphology, genomics, taxonomy, evolution, replication, transmission, pathogenesis, and control of phenuiviruses, to aid researchers in various fields to recognize this highly adaptive and important virus family and conduct relevant risk analysis. Key Points/Highlights: 1.This review draws a novel panorama for the virus family Phenuiviridae.2.Phenuiviridae has importance in the health of humans, animals, and plants.3.Structures, functions, and evolution of phenuivirid genes were reviewed.4.Pathogenesis, epidemiology, and control of phenuiviruses were reviewed. [ABSTRACT FROM AUTHOR]

Objective: Causes of acute febrile illness (AFI) often remain undetermined in developing countries, due to overlap of symptoms and limited available diagnostics. We aimed to assess the aetiology of AFI in adults in a referral hospital in northwest Ethiopia. Methods: While all participants were tested for malaria by rapid diagnostic test (RDT), microscopy was only done on physician's request. Dengue virus (DENV) infections were detected using an RDT and ELISAs and dengue, yellow fever and chikungunya cases were identified by PCR. Bacterial aetiologies were investigated using blood culture and PCR. Results: The aetiology of acute infection was identified for 20.5% of 200 patients enrolled. Eleven percent tested positive for Plasmodium, while microscopy was only requested for half of the identified malaria cases. For 4.0% of the Plasmodium‐infected patients, an acute or past DENV (co‐)infection was detected. We found 7.5% acute and 13.0% past DENV – all serotype 3 – infections. Bacterial infections were observed in 4.5% of the patients. Conclusion: Malaria is still a considerable aetiology of AFI and dengue is underrecognised. There are areas where both diseases occur concomitantly, and the DENV‐3 serotype presumably spreads from Sudan to northern Ethiopia. As only 20.5% of the aetiologies were identified, a broader testing platform is required. [ABSTRACT FROM AUTHOR]

We describe the circulation of Saint Louis encephalitis virus (SLEV) in two Brazilian States during outbreaks of Dengue and Zika viruses. We detected the virus in a patient from Araraquara, State of São Paulo, and in patients and in a mosquito pool of Culex quinquefasciatus from Sinop, State of Mato Grosso. Phylogenetic analysis grouped samples from this study within genotype V, which are closely related to other strains that previously circulated in other parts of the country. Genotype V seems to have established circulation in Brazil. Highlights: During epidemics of DENV and ZIKV, we detected SLEV in human and mosquito samples from two different Brazilian States;SLEV detected in our samples belong to Genotype V of the virus;The detection of SLEV was only possible because there were active arbovirus surveillance protocols in both areas; [ABSTRACT FROM AUTHOR]

The distribution of disease vectors such as mosquitoes is changing. Climate change, invasions and vector control strategies all alter the distribution and abundance of mosquitoes. When disease vectors undergo a range shift, so do disease burdens. Predicting such shifts is a priority to adequately prepare for disease control. Accurate predictions of distributional changes depend on how factors such as temperature and competition affect mosquito life‐history traits, particularly body size and reproduction. Direct estimates of both body size and reproduction in mosquitoes are logistically challenging and time‐consuming, so the field has long relied upon linear (isometric) conversions between wing length (a convenient proxy of size) and reproductive output. These linear transformations underlie most models projecting species' distributions and competitive interactions between native and invasive disease vectors. Using a series of meta‐analyses, we show that the relationship between wing length and fecundity are nonlinear (hyperallometric) for most mosquito species. We show that whilst most models ignore reproductive hyperallometry (with respect to wing length), doing so introduces systematic biases into estimates of population growth. In particular, failing to account for reproductive hyperallometry overestimates the effects of temperature and underestimates the effects of competition. Assuming isometry also increases the potential to misestimate the efficacy of vector control strategies by underestimating the contribution of larger females in population replenishment. Finally, failing to account for reproductive hyperallometry and variation in body size can lead to qualitative errors via the counter‐intuitive effects of Jensen's inequality. For example, if mean sizes decrease, but variance increases, then reproductive outputs may actually increase. We suggest that future disease vector models incorporate hyperallometric relationships to more accurately predict changes in mosquito distribution in response to global change. [ABSTRACT FROM AUTHOR]

Viremia in the vertebrate host is a major determinant of arboviral reservoir competency, transmission efficiency, and disease severity. However, immune mechanisms that control arboviral viremia are poorly defined. Here, we identify critical roles for the scavenger receptor MARCO in controlling viremia during arthritogenic alphavirus infections in mice. Following subcutaneous inoculation, arthritogenic alphavirus particles drain via the lymph and are rapidly captured by MARCO+ lymphatic endothelial cells (LECs) in the draining lymph node (dLN), limiting viral spread to the bloodstream. Upon reaching the bloodstream, alphavirus particles are cleared from the circulation by MARCO‐expressing Kupffer cells in the liver, limiting viremia and further viral dissemination. MARCO‐mediated accumulation of alphavirus particles in the draining lymph node and liver is an important host defense mechanism as viremia and viral tissue burdens are elevated in MARCO−/− mice and disease is more severe. In contrast to prior studies implicating a key role for lymph node macrophages in limiting viral dissemination, these findings exemplify a previously unrecognized arbovirus‐scavenging role for lymphatic endothelial cells and improve our mechanistic understanding of viremia control during arthritogenic alphavirus infection. Synopsis: Lymphatic endothelial cells (LECs) in the draining lymph node and Kupffer cells (KCs) in liver sinusoids limit alphavirus dissemination to tissues and the development of viremia, which are essential for arbovirus pathogenicity and transmission, via the scavenger receptor MARCO. The draining lymph node (dLN) impedes viremia and viral dissemination via the scavenger receptor MARCO during arthritogenic alphavirus infections.MARCO+ lymphatic endothelial cells (LECs) in the dLN capture and internalize arthritogenic alphavirus particles to limit viral dissemination to the blood.Kupffer cells in the liver capture circulating alphavirus particles that breach the lymph node barrier to access the bloodstream, providing a second line of MARCO‐dependent defense.MARCO−/− mice have an increased magnitude and duration of viremia, enhanced viral dissemination, and more severe disease outcomes. [ABSTRACT FROM AUTHOR]

The effects of climate change on infectious diseases are a topic of considerable interest and discussion. We studied West Nile virus (WNV) in New York (NY) and Connecticut (CT) using a Weather Research and Forecasting (WRF) model climate change scenario, which allows us to examine the effects of climate change and variability on WNV risk at county level. We chose WNV because it is well studied, has caused over 50,000 reported human cases, and over 2200 deaths in the United States. The ecological impacts have been substantial (e.g., millions of avian deaths), and economic impacts include livestock deaths, morbidity, and healthcare‐related expenses. We trained two Random Forest models with observational climate data and human cases to predict future levels of WNV based on future weather conditions. The Regional Model used present‐day data from NY and CT, whereas the Analog Model was fit for states most closely matching the predicted future conditions in the region. Separately, we predicted changes to mosquito‐based WNV risk using a trait‐based thermal biology approach (Mosquito Model). The WRF model produced control simulations (present day) and pseudo‐global warming simulations (future). The Regional and Analog Models predicted an overall increase in human cases of WNV under future warming. However, the Analog Model did not predict as strong of an increase in the number of human cases as the Regional Model, and predicted a decrease in cases in some counties that currently experience high numbers of WNV cases. The Mosquito Model also predicted a decrease in risk in current high‐risk areas, with an overall reduction in the population‐weighted relative risk (but an increase in area‐weighted risk). The Mosquito Model supports the Analog Model as making more realistic predictions than the Regional Model. All three models predicted a geographic increase in WNV cases across NY and CT. [ABSTRACT FROM AUTHOR]

BACKGROUND: Dragonfly and damselfly larvae have been considered as possible biocontrol agents against young instars of mosquito vectors in urban environments. Yet our knowledge about adult odonate predation against mosquito adults is scarce. We quantified daily and annual predation rates, consumption rates and prey preferences of adult Hetaerina vulnerata male damselflies in an urban park. A focus on predation of mosquito species was provided, quantified their arbovirus (dengue, chikungunya and Zika) infection rates and biting activity. RESULTS: Foraging times of H. vulnerata overlapped with those of the maximum activity of hematophagous mosquitoes. The most consumed preys were Diptera and Hymenoptera and, in lower quantities, Hemiptera, Coleoptera, Trichoptera, Psocoptera and Neuroptera. Of note, 7% of the diet was represented by hematophagous dipterans, with 2.4% being Aedes aegypti and Aedes albopictus. Prey abundance in the diet coincided with that of the same species in the environment. The arboviral infection rate (dengue, chikungunya and Zika) was 1.6% for A. aegypti and A. albopictus. The total biting rate of these mosquito vectors was 16 bites per person per day, while the annual rate of infectious bites was 93.4. CONCLUSION: Although 2.4% for both Aedes species seems a low consumption, considering the presence of 12 odonate species at the park, it can be argued that adult odonates may play a relevant role as mosquito vector regulators, therefore impacting the spread of mosquito‐borne diseases. Our study outlines the need for further research on the topic of the possible role of adult odonates for mosquito biocontrol. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Aedes mosquitoes (Diptera: Culicidae), principle vectors of several arboviruses, typically lay eggs in man‐made water‐filled containers located near human dwellings. Given the widespread emergence of insecticide resistance, stable and biofriendly alternatives for mosquito larviciding are needed. Laboratory studies have demonstrated that inactivated yeast interfering RNA tablets targeting key larval developmental genes can be used to facilitate effective larvicidal activity while also promoting selective gravid female oviposition behaviour. Here we examined the efficacy of transferring this technology toward development of lure‐and‐kill ovitraps targeting Aedes aegypti (L.) and Aedes albopictus (Skuse) female mosquitoes. Insectary, simulated field and semi‐field experiments demonstrated that two mosquito‐specific yeast interfering RNA pesticides induce high levels of mortality among larvae of both species in treated large volume containers. Small‐scale field trials conducted in Trinidad, West Indies demonstrated that large volume ovitrap containers baited with inactivated yeast tablets lure significantly more gravid females than traps containing only water and were highly attractive to both A. aegypti and A. albopictus females. These studies indicate that development of biorational yeast interfering RNA‐baited ovitraps may represent a new tool for control of Aedes mosquitoes, including deployment in existing lure‐and‐kill ovitrap technologies or traditional container larviciding programs. [ABSTRACT FROM AUTHOR]

Herein, we describe a unique case of concomitant angioinvasive pulmonary aspergillosis due to Aspergillus fumigatus and yellow fever in a free‐ranging howler monkey (Alouatta sp). Lung samples were negative for influenza viruses A and B. [ABSTRACT FROM AUTHOR]

Culicoides Latreille (Diptera: Ceratopogonidae) transmit arboviruses affecting wild and domestic ruminants such as bluetongue (BTV) and Schmallenberg virus (SBV). The sub‐adult development and lifespan of Culicoides obsoletus s.s. (Meigen), Culicoides circumscriptus Kieffer and Culicoides paolae Boorman were examined at three different temperatures under laboratory conditions. Insects were collected from field between spring and autumn 2015 in two livestock farms located in Majorca (Spain). Gravid females were held individually at 18, 25 or 30 °C. Low temperatures increased the adult lifespan, time to oviposit and rate of development, whereas high temperatures increased the number of eggs, successful pupation and adult emergence as well as the larvae growth rate. The results showed that C. obsoletus s.s. have optimum development at 18 °C, whereas the optimal rearing temperature for C. circumscriptus and C. paolae was under warmer conditions of 25–30 °C. Variations in temperature/humidity and assays with different materials and substrates for oviposition should be considered in future studies. Understanding the requirements of the different species of Culicoides optimizing the results should be of special interest for predicting environmental change effects on these species, in addition to determining the rearing conditions for candidate Culicoides vectors. [ABSTRACT FROM AUTHOR]

Ticks are the primary vector of arboviruses in temperate climates worldwide. They are both the vector of these pathogens to humans and an integral component of the viral sylvatic cycle. Understanding the tick‐pathogen interaction provides information about the natural maintenance of these pathogens and informs the development of countermeasures against human infection. In this review, we discuss currently available information on tick‐viral interactions within the broader scope of general tick immunology. While the tick immune response to several pathogens has been studied extensively, minimal work centres on responses to viral infection. This is largely due to the high pathogenicity of tick‐borne viruses; this necessitates high‐containment laboratories or low‐pathogenicity substitute viruses. This has biased most research towards tick‐borne flaviviruses. More work is required to fully understand the role of tick‐virus interaction in sylvatic cycling and transmission of diverse tick‐borne viruses. [ABSTRACT FROM AUTHOR]

Landscape change is one of the foremost drivers of the emergence of infectious diseases. Exploring demographic, household and environmental conditions under which infectious diseases occur may inform strategies to prevent disease emergence in human populations. We collected blood samples from 523 humans and explore factors for arbovirus emergence in Bahia, Brazil. The overall arbovirus seroprevalence was 65.2%, with the genus Flavivirus most prevalent (64.4%). Based on monotypic reactions, the population had contact with five arbovirus: Dengue 3, Ilheus, Oropouche, Caraparu and Eastern equine encephalitis virus. To our knowledge, this is the first study reporting exposure to Oropouche, Caraparu and Eastern equine encephalitis virus in human populations in Bahia, Northeast of Brazil. The best model fit demonstrated that household and environmental variables were more predictive of the risk of arbovirus exposure than demographic variables. The presence of forest and free‐living monkeys in the areas close to the communities had a protective effect for the human population (i.e. lower seroprevalence). The dilution effect is considered as one explanation for this finding. These results highlight the important ecological role of wildlife‐friendly agriculture. [ABSTRACT FROM AUTHOR]

Experiments and models suggest that climate affects mosquito‐borne disease transmission. However, disease transmission involves complex nonlinear interactions between climate and population dynamics, which makes detecting climate drivers at the population level challenging. By analysing incidence data, estimated susceptible population size, and climate data with methods based on nonlinear time series analysis (collectively referred to as empirical dynamic modelling), we identified drivers and their interactive effects on dengue dynamics in San Juan, Puerto Rico. Climatic forcing arose only when susceptible availability was high: temperature and rainfall had net positive and negative effects respectively. By capturing mechanistic, nonlinear and context‐dependent effects of population susceptibility, temperature and rainfall on dengue transmission empirically, our model improves forecast skill over recent, state‐of‐the‐art models for dengue incidence. Together, these results provide empirical evidence that the interdependence of host population susceptibility and climate drives dengue dynamics in a nonlinear and complex, yet predictable way. [ABSTRACT FROM AUTHOR]

Mosquitoes are effective vectors of disease‐causing organisms, and some species are duly very well‐studied organisms. Little fundamental biology is known for a large proportion of mosquito taxa, especially in the Afrotropics, including mosquitoes preferring herpetofauna as blood hosts. Since mosquitoes are effective vectors of pathogens, mosquitoes using herpetofauna as hosts require some scientific scrutiny, especially in light of the global decline of reptiles and amphibians. Beyond taxonomic studies, very little is known about pathogens, indigenous or alien, circulating among the Afrotropical herpetofauna. Hepatozoon spp., arguably the best studied vector‐borne pathogens affecting herpetofauna in the region, are used to illustrate this neglect and discussed in light of conservation. Apart from conservation, complex arbovirus disease dynamics warrant a renewed interest in rarely collected mosquito species, including species using herpetofauna as blood hosts. Finally, the literature pertaining to herpetophilic mosquitoes in the Afrotropics is reviewed and compared to that generated elsewhere, and taxa of interest are discussed including references to other haematophagous dipterans feeding on herpetofauna in the region. [ABSTRACT FROM AUTHOR]

Objective: In Brazil, the most common method of controlling outbreaks of arbovirus is by the use of chemical sprays, which kill the insect vector, Aedes aegypti. The main objective of this study was to evaluate the resistance of Ae. aegypti to the insecticide, malathion, in situ. The location of this study was the municipality of Foz do Iguaçu, in the state of Paraná, Brazil. Methods: Ultra‐low‐volume (ULV) fogging equipment was used, by vehicle, to apply the insecticide in situ, and mosquito populations after treatment were compared with those of control areas. The resistance of strains collected from the municipality was compared to the Rockefeller strain under laboratory conditions. Results: We found 220 adult female specimens and 7423 eggs of Ae. aegypti in the areas subjected to UBV treatment, whereas 245 adult females and 10 557 eggs were found in the control areas. The UBV treatment area showed no significant difference compared to the control area, for all the indices. Mortality of the Rockefeller colony varied more quickly when there were slight variations in malathion concentration than the Foz do Iguaçu population. [ABSTRACT FROM AUTHOR]

Background and objectives: French Polynesia, where dengue virus (DENV) has been present for a long time, experienced two successive outbreaks of Zika (ZIKV) and chikungunya viruses (CHIKV) between 2013 and 2015. To avoid the transmission of these viruses by transfusion, nucleic acid testing (NAT) has been in place for DENV since 2013 and for ZIKV and CHIKV during epidemics. The objective was to compare the estimated risk of viraemic blood donation with NAT results and to discuss the impact on the prevention of transfusion‐related infectious risk. Materials and methods: The average risks of viraemic blood donation were estimated per year for DENV, and during the epidemic periods for ZIKV and CHIKV, using the Biggerstaff and Petersen model based on the incidence rate, the mean length of viraemia and the frequency of asymptomatic infection. The estimated risks were compared with the number of viraemic blood donations detected by NAT. Results: According to the different assumptions, risks estimates ranged from 11·2 to 53·1/100 000 donations for DENV, 746 to 1924/100 000 for ZIKV and 1083 /100 000 for CHIKV. When compared to the number of donations collected during the study periods, these estimates match NAT results (5 blood donors reactive for DENV, 42 for ZIKV and 34 for CHIKV). Conclusion: The risks of viraemic blood donation were related to the viral incidence in the general population and concordant with NAT results. These findings suggest that the screening may be optimized by a targeted NAT implementation based on incidence data. [ABSTRACT FROM AUTHOR]

Jamestown Canyon virus (JtCV) is an arbovirus and a member of the California serogroup. To our knowledge, all the cases of JtCV have been reported in immunocompetent patients since it was first detected in 1997. We report a case of JtCV encephalitis in a solid organ transplant patient. A 48‐year‐old woman from Wisconsin had multiple hospital admissions for symptoms of progressive confusion, visual hallucinations, and inability to perform self‐care. Initial evaluation was significant for lymphocytes in cerebrospinal fluid (CSF), and multiple infectious and metabolic causes were excluded. Further investigation found JtCV IgM in serum, and CSF. The patient's clinical course was compatible with JtCV encephalitis, and she was treated with ribavirin in addition to reduction of her immunosuppressive medications. She showed gradual and significant improvement in her mental and functional status. JtCV can cause a variety of symptoms that range from a flu‐like syndrome to encephalitis. There have been an increased number of reported cases in recent years which is attributed to increased physician awareness and the availability of laboratory testing. Optimal treatment is still not known. [ABSTRACT FROM AUTHOR]

Objectives: In Brazil, the National Policy for Dengue Control seeks to incorporate the lessons of national and international experience in dengue control, emphasising the need for health education activities. The objective of this study was to evaluate and compare knowledge, attitudes and behaviours related to the prevention of arboviruses before and after a two-month educational intervention using a learning platform on mobile devices.Methods: This quasi-experimental study corresponds to the first phase of the project 'Impact of mobile learning in the prevention and management of complications caused by arboviruses (Zika, Dengue, Chikungunya) - ZIKAMOB', sponsored as part of the British Council Newton Fund.Results: Thirty of the 93 participants were first-year undergraduate university students (36.7% male), and 63 were police officers (84.1% male). The pattern of attitudes and behaviour was very similar in both groups before the intervention. The students changed their attitudes and behaviour (P = 0.032) in relation to their engagements in actions for the prevention of arboviral diseases and several other activities related to house inspections and precautions with water tanks (P < 0.01). However, recycling and surveillance activities were not as effective in changing behaviour. Female participants showed more motivation to participate in preventive activities, but living alone and working were barriers to participation. Individuals who already perform selective waste collection and are cultivating gardens demonstrated both a positive attitude and a positive behaviour towards actions for the prevention of arboviral diseases.Conclusion: Mobile learning and behaviour change theories might be successful as the basis for school-based and community-based interventions to avoid arboviruses. These outcomes need to be confirmed in broader future studies. [ABSTRACT FROM AUTHOR]

Mosquito‐borne diseases cause a major burden of disease worldwide. The vital rates of these ectothermic vectors and parasites respond strongly and nonlinearly to temperature and therefore to climate change. Here, we review how trait‐based approaches can synthesise and mechanistically predict the temperature dependence of transmission across vectors, pathogens, and environments. We present 11 pathogens transmitted by 15 different mosquito species – including globally important diseases like malaria, dengue, and Zika – synthesised from previously published studies. Transmission varied strongly and unimodally with temperature, peaking at 23–29ºC and declining to zero below 9–23ºC and above 32–38ºC. Different traits restricted transmission at low versus high temperatures, and temperature effects on transmission varied by both mosquito and parasite species. Temperate pathogens exhibit broader thermal ranges and cooler thermal minima and optima than tropical pathogens. Among tropical pathogens, malaria and Ross River virus had lower thermal optima (25–26ºC) while dengue and Zika viruses had the highest (29ºC) thermal optima. We expect warming to increase transmission below thermal optima but decrease transmission above optima. Key directions for future work include linking mechanistic models to field transmission, combining temperature effects with control measures, incorporating trait variation and temperature variation, and investigating climate adaptation and migration. [ABSTRACT FROM AUTHOR]

Vertical transmission to progeny ensures the maintenance of arboviruses in their natural vectors. This mechanism is largely reported for dengue virus (DENV) and yellow fever virus (YFV). Few studies have addressed this mechanism for Zika virus (ZIKV), Mayaro virus (MAYV) and other arboviruses. The present study investigated the natural infection rate by arboviruses in 4490 Aedes (Stegomyia) aegypti and 296 Aedes (Stegomyia) albopictus (Diptera: Culicidae) reared from eggs collected with ovitraps in Cuiabá, Mato Grosso State, from February to July, 2017. After viral RNA extraction and reverse transcriptase‐polymerase chain reaction protocols for 10 flaviviruses and five alphaviruses, nucleotide sequencing and three passages in C6/36 cells, eight pools of Ae. aegypti positive for DENV‐4 genotype II, seven for ZIKV Asian genotype and two for MAYV genotype L were found. In addition, two Ae. albopictus pools were positive for DENV‐4 genotype II and two were positive for ZIKV Asian genotype. Infection was confirmed by viral isolation in all positive pools for DENV‐4 and for MAYV and in eight of nine for ZIKV. This mechanism may contribute to the spread of arboviruses during epidemics and also to their maintenance in natural vectors during interepidemic periods. [ABSTRACT FROM AUTHOR]

A promising strategy for reducing the transmission of dengue and other arboviral human diseases by Aedes aegypti mosquito vector populations involves field introductions of the endosymbiotic bacteria Wolbachia. Wolbachia infections inhibit viral transmission by the mosquito, and can spread between mosquito hosts to reach high frequencies in the vector population. Wolbachia spreads by maternal transmission, and spread dynamics can be variable and highly dependent on natural mosquito population dynamics, population structure and fitness components.We develop a mathematical model of an A. aegypti metapopulation that incorporates empirically validated relationships describing density‐dependent mosquito fitness components. We assume that density dependent relationships differ across subpopulations, and construct heterogeneous landscapes for which model‐predicted patterns of variation in mosquito abundance and demography approximate those observed in field populations. We then simulate Wolbachia release strategies similar to that used in field trials.We show that our model can produce rates of spatial spread of Wolbachia similar to those observed following field releases.We then investigate how different types of spatio‐temporal variation in mosquito habitat, as well as different fitness costs incurred by Wolbachia on the mosquito host, influence predicted spread rates. We find that fitness costs reduce spread rates more strongly when the habitat landscape varies temporally due to stochastic and seasonal processes.Synthesis and applications: Our empirically based modelling approach represents effects of environmental heterogeneity on the spatial spread of Wolbachia. The models can assist in interpreting observed spread patterns following field releases and in designing suitable release strategies for targeting spatially heterogeneous vector populations. Our empirically based modelling approach represents effects of environmental heterogeneity on the spatial spread of Wolbachia. The models can assist in interpreting observed spread patterns following field releases and in designing suitable release strategies for targeting spatially heterogeneous vector populations. [ABSTRACT FROM AUTHOR]

Surveillance of adult Culicoides biting midge flight activity is used as an applied ecological method to guide the management of arbovirus incursions on livestock production in Europe and Australia.To date the impact of changes in the phenology of adult vector activity on arbovirus transmission has not been defined. We investigated this at two sites in the UK, identifying 150,000 Culicoides biting midges taken from 2867 collections over a nearly 40 year timescale.Whilst we recorded no change in seasonal activity at one site, shifts in first adult appearance and last adult appearance increased the seasonal activity period of Culicoides species at the other site by 40 days over the time period.Lengthening of the adult activity season was driven by an increase in abundance of Culicoides and correlated with local increases in temperature and precipitation. This diversity in responses poses significant challenges for predicting future transmission and overwintering risk.Policy implications. Our analysis not only shows a dramatic and consistent increase in the adult active period of Culicoides biting midges, but also that this varies significantly between sites. This suggests broad‐scale analyses alone are insufficient to understand the potential impacts of changes in climate on arbovirus vector populations. Understanding the impact of climate change on adult Culicoides seasonality and transmission of arboviruses requires the context of changes in a range of other local ecological drivers. [ABSTRACT FROM AUTHOR]

The incidence of arbovirus infections has increased dramatically in recent decades, affecting hundreds of millions of people each year. The Togaviridae family includes the chikungunya virus (CHIKV), which is typically transmitted by Aedes mosquitoes and causes a wide range of symptoms from flu‐like fever to severe arthralgia. Although conventional diagnostic tests can provide early diagnosis of CHIKV infections, access to these tests is often limited in developing countries. Consequently, there is an urgent need to develop efficient, affordable, simple, rapid, and robust diagnostic tools that can be used in point‐of‐care settings. Early diagnosis is crucial to improve patient management and to reduce the risk of complications. A glass‐fiber laser‐cut microfluidic device (paper‐based analytical device [PAD]) was designed and evaluated in a proof of principle context, for the analysis of 30 µL of patient serum. Biological raw materials used for the functionalization of the PAD were first screened by MAC‐ELISA (IgM capture enzyme‐linked immunosorbent assay) for CHIKV Immunoglobulin M (IgM) capture and then evaluated on the PAD using various human samples. Compared with viral lysate traditionally used for chikungunya (CHIK) serology, CHIKV pseudo‐particles (PPs) have proven to be powerful antigens for specific IgM capture. The PAD was able to detect CHIKV IgM in human sera in less than 10 minutes. Results obtained in patient sera showed a sensitivity of 70.6% and a specificity of around 98%. The PAD showed few cross‐reactions with other tropical viral diseases. The PAD could help health workers in the early diagnosis of tropical diseases such as CHIK, which require specific management protocols in at‐risk populations. [ABSTRACT FROM AUTHOR]

Since at least 2015, a major Zika virus epidemic has impacted the Americas and the Caribbean. There is an ongoing risk of Aedes mosquito‐borne transmission in more than 90 countries and territories worldwide. In these areas, as well as in places that are not experiencing active outbreaks, workers in a variety of jobs may be exposed to the virus. In addition to outdoor workers in places with ongoing, vector‐borne transmission who may be exposed when bitten by Zika‐infected mosquitoes, biomedical researchers studying the virus and health care workers and staff in clinical laboratories may encounter blood and infectious body fluids from infected individuals, including travelers from Zika virus‐affected areas. Because of potentially serious health outcomes, including reproductive effects, sometimes associated with Zika, the Occupational Safety and Health Administration and National Institute for Occupational Safety and Health previously issued guidance to help US employers protect workers from exposure to the virus on the job. This commentary summarizes the details of these recommendations and explains their rationale, which is important to understand when adapting and implementing workplace controls to prevent occupational Zika virus exposures and infections at individual worksites. The industrial hygiene hierarchy of controls, including elimination and substitution, engineering controls, administrative controls, and safe work practices, and personal protective equipment, serves as a framework for infection prevention practices for at‐risk workers discussed here. [ABSTRACT FROM AUTHOR]

Simbu serogroup are arbo‐ viruses which are mainly transmitted by Culicoides. Two members of the Simbu serogroup, Akabane and Shuni viruses, have been isolated from congenitally malformed ruminants in Israel. A recent serosurvey revealed that Israeli ruminants have been exposed to several additional Simbu viruses, including Shamonda and Sathuperi that seems to be circulating in Israel. In April 2017, an apparently healthy one‐month‐old male calf was transferred to the Kimron Veterinary Institute. A few days later, the calf was reported to be slow to respond to its surroundings and was not able to feed on its own. Blindness was observed upon clinical examination. RNA of the small, medium and large segments of Simbu serogroup viruses were amplified and sequenced from the testis tissues and from the Cerebrospinal fluid (CSF). During post‐mortem examination, hydranencephaly was defined. Phylogenetic analysis of all three segments of Simbu serogroup viruses showed that the sequences detected in the Israeli calf were virtually identical to Peaton virus (PEAV). PEAV was also detected in two pools of Culicoides imicola trapped at two different locations in Israel. This is the first genomic detection of PEAV outside Australia and Japan. These results are of epidemiological significance, as they demonstrate that PEAV is circulating in Israel and affects cattle. Consequently, these results are also of relevance to a potential spread of Simbu serogroup viruses into Europe. Genomic fragments of Peaton virus were detected in a calf exhibiting micro‐hydranenchepaly and in two pools of Culicides imicola in Israel. This is the first genomic detection of this virus outside Australia and Japan. Our results are of relevance to the potential spread of Simbu viruses into Europe. [ABSTRACT FROM AUTHOR]

Objective: To study the distribution of vertical transmission of dengue viruses in field-collected Aedes aegypti larvae in the municipality of Arroyo Naranjo in Havana, Cuba.Methods: Aedes aegypti larvae and pupae were collected monthly between September 2013 and July 2014 in the seven Municipal Health Areas of Arroyo Naranjo. Pools formed of 30-55 larvae were examined through PCR and sequencing to detect the presence of each serotype.Results: We analysed 111 pools of larvae and pupae (4102 individuals) of which 37 tested positive for at least one DENV. More than one DENV type was observed in 10 of the 37 positive pools. Infected pools were detected every month, except in January, suggesting a sustained circulation of DENV in the vector populations. DENV-1 and DENV-3 were the most frequent and dispersed, though all four DENV types were detected. Nucleotide sequencing from positive pools confirmed RT-PCR results for DENV-1 (genotype V), DENV-3 (genotype III) and DENV-4 (genotype II). DENV-2 was detected by RT-PCR but could not be confirmed by nucleotide sequencing.Conclusion: Our study of the distribution of natural vertical transmission of dengue virus types highlights extrinsic virus activity patterns in the area and could be used as a new surveillance tool. [ABSTRACT FROM AUTHOR]

Antibody detection against selected potentially zoonotic vector-borne alphaviruses and flaviviruses was conducted on sera from bats from all six parishes in Grenada, West Indies. Sera were tested for (i) antibodies to flaviviruses West Nile virus, St. Louis encephalitis virus, Ilhéus virus, Bussuquara virus (BSQV), Rio Bravo virus and all four serotypes of dengue virus (DENV) by plaque reduction neutralization test (PRNT); (ii) antibodies to alphaviruses western equine encephalitis virus, Venezuelan equine encephalitis virus and eastern equine encephalitis virus by epitope-blocking enzyme-linked immunosorbent assay (ELISA); and (iii) antibodies to the alphavirus chikungunya (CHIKV) by PRNT. Two species of fruit bats were sampled, Artibeus jamaicensis and Artibeus lituratus, all roosting in or within 1,000 m of human settlements. Fifteen (36%) of the 42 bats tested for neutralizing antibodies to CHIKV were positive. The CHIKV-seropositive bats lived in localities spanning five of the six parishes. All 43 bats tested for epitope-blocking ELISA antibody to the other alphaviruses were negative, except one positive for Venezuelan equine encephalitis virus. All 50 bats tested for neutralizing antibody to flaviviruses were negative, except one that had a BSQV PRNT80 titre of 20. The CHIKV serology results indicate that bats living close to and within human settlements were exposed to CHIKV in multiple locations. Importantly, bats for this study were trapped a year after the introduction and peak of the human CHIKV epidemic in Grenada. Thus, our data indicate that bats were exposed to CHIKV possibly during a time of marked decline in human cases. [ABSTRACT FROM AUTHOR]

Summary: Equine populations worldwide are at increasing risk of infection by viruses transmitted by biting arthropods, including mosquitoes, biting midges (Culicoides), sandflies and ticks. These include the flaviviruses (Japanese encephalitis, West Nile and Murray Valley encephalitis), alphaviruses (eastern, western and Venezuelan encephalitis) and the orbiviruses (African horse sickness and equine encephalosis). This review provides an overview of the challenges faced in the surveillance, prevention and control of the major equine arboviruses, particularly in the context of these viruses emerging in new regions of the world. [ABSTRACT FROM AUTHOR]

Abstract: The epidemic of Zika in the Western hemisphere has led to intense investigations of all species important in the transmission of Zika virus (ZikV), including putative mosquito vectors. Although evidence points to Stegomyia (= Aedes) (Diptera: Culicidae) mosquitoes as the primary vectors in nature among humans, there remains the possibility that other common mosquito species may be implicated in the rapid spread of the virus. Herein, field‐caught Culex quinquefasciatus (Diptera: Culicidae) collected during June 2016 in different neighbourhoods in San Juan, Puerto Rico were examined for the presence of natural infection with ZikV. Stegomyia aegypti (= Aedes aegypti) from the same locations were also analysed. None of the Cx. quinquefasciatus tested showed natural infection for ZikV, whereas S. aegypti tested positive at seven sites. The present results suggest that Cx. quinquefasciatus was not involved in the transmission of ZikV in San Juan, Puerto Rico in 2016. [ABSTRACT FROM AUTHOR]

Summary: A serosurvey for Tahyna virus (TAHV), a mosquito‐borne California encephalitis orthobunyavirus (Peribunyaviridae) endemic to Europe, was performed to estimate the activity of TAHV on a broad geographic scale. Sera from wild boar (Sus scrofa), roe deer (Capreolus capreolus) and red deer (Cervus elaphus) were collected from Austria, Hungary and Romania. Samples were tested for neutralizing antibodies against TAHV using a virus microneutralization assay. The results demonstrate that TAHV transmission to mammals is widespread in Europe, particularly in the wild boar population where the mean rate of seroconversion is 15.2%. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Control of the container‐inhabiting mosquito, Aedes albopictus, is difficult using conventional methods due to its selection of cryptic peri‐domestic habitats. We evaluated whether autodissemination stations can deliver sufficient pyriproxyfen to sentinel containers to produce significant pupal mortality in different habitats such as competing oviposition sites, peri‐domestic habitats, junkyards and tire piles. We also tested how far the pesticide could be transferred over a 200‐m range. RESULTS: Autodissemination stations performed effectively for 8–12 weeks under field conditions. Pupal mortality was reduced in sentinel cups with high‐competing oviposition habitats (5 versus 20) in isolated plots; however, similar results were not seen in residential areas. Increasing the number of stations per plot (from 1 to 4) enhanced the efficacy. Peri‐domestic habitat trials showed the highest pupal mortality (50.4%) and site contamination with pyriproxyfen (82.2%) among the trials. Autodissemination stations were able to contaminate habitats in a junkyard (50.0%) and tire piles (40.2%). Pyriproxyfen was detected in sentinel cups up to 200 m from stations. Detection of pyriproxyfen by residue analysis (0.005–0.741 µg L−1) in field samples confirmed the transfer of the insect growth regulator. CONCLUSION: Autodissemination stations have shown promising potential as a novel pest management tool against container mosquitoes in field trials in different habitats confronted by mosquito control personnel. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Summary: Since the 1980s, a comprehensive field and laboratory investigation has been conducted throughout China, and a total of 29 virus species belonging to 7 families and 13 genera were identified through virological, morphological, and immunological methods, as well as whole‐genome sequencing and molecular genetic analyses. Most of the virus isolates belong to 9 genera in the families Flaviviridae, Bunyaviridae, Togaviridae, and Reoviridae. Among them, 4 genera (Orthobunyavirus, Bunyavirus, Phlebovirus, and Nairovirus) belong to the family Bunyaviridae and 3 genera (Seadonavirus, Orbivirus, and Cypovirus) belong to the family Reoviridae. Analyses of the relationships between viruses and human/animal diseases indicated that Japanese encephalitis virus, dengue virus, severe fever with thrombocytopenia syndrome virus, tick‐borne encephalitis virus, Crimean‐Congo hemorrhagic fever virus, West Nile virus, and Tahyna virus can cause human and animal infections and disease epidemics in China. This review systematically introduces the current status of the diversity and geographical distribution of arboviruses and vectors in China. In addition, our results provide strong technical support for the prevention and control of arboviral diseases, the treatment of epidemics, and the early warning and prediction of diseases, and so they are significant for the control and prevention of arboviral diseases in Asia and around the world. [ABSTRACT FROM AUTHOR]

By serving as vectors of transmission, insects play a key role in the infection cycle of many plant viruses. Viruses use sophisticated transmission strategies to overcome the spatial barrier separating plants and the impediment imposed by the plant cell wall. Interactions among insect vectors, viruses, and host plants mediate transmission by integrating all organizational levels, from molecules to populations. Best-examined on the molecular scale are two basic transmission modes wherein virus-vector interactions have been well characterized. Whereas association of virus particles with specific sites in the vector's mouthparts or in alimentary tract regions immediately posterior to them is required for noncirculative transmission, the cycle of particles through the vector body is necessary for circulative transmission. Virus transmission is also determined by interactions that are associated with changes in vector feeding behaviors and with alterations in plant host's morphology and/or metabolism that favor the attraction or deterrence of vectors. A recent concept in virus-host-vector interactions proposes that when vectors land on infected plants, vector elicitors and effectors 'inform' the plants of the confluence of interacting entities and trigger signaling pathways and plant defenses. Simultaneously, the plant responses may also influence virus acquisition and inoculation by vectors. Overall, a picture is emerging where transmission depends on multilayered virus-vector-host interactions that define the route of a virus through the vector, and on the manipulation of the host and the vector. These interactions guarantee virus propagation until one or more of the interactants undergo changes through evolution or are halted by environmental interventions. [ABSTRACT FROM AUTHOR]

The effective population size ( N e) is a fundamental parameter in population genetics that determines the relative strength of selection and random genetic drift, the effect of migration, levels of inbreeding, and linkage disequilibrium. In many cases where it has been estimated in animals, N e is on the order of 10%-20% of the census size. In this study, we use 12 microsatellite markers and 14,888 single nucleotide polymorphisms ( SNPs) to empirically estimate N e in Aedes aegypti, the major vector of yellow fever, dengue, chikungunya, and Zika viruses. We used the method of temporal sampling to estimate N e on a global dataset made up of 46 samples of Ae. aegypti that included multiple time points from 17 widely distributed geographic localities. Our N e estimates for Ae. aegypti fell within a broad range (~25-3,000) and averaged between 400 and 600 across all localities and time points sampled. Adult census size (Nc) estimates for this species range between one and five thousand, so the N e/ N c ratio is about the same as for most animals. These N e values are lower than estimates available for other insects and have important implications for the design of genetic control strategies to reduce the impact of this species of mosquito on human health. [ABSTRACT FROM AUTHOR]

In Europe, West Nile virus ( WNV) outbreaks have been limited to southern and central European countries. However, competent mosquito vectors and susceptible bird hosts are present in northern Europe. Differences in temperature and vector competence of mosquito populations may explain the absence of WNV outbreaks in northern Europe. The aim of the present study was to directly compare vector competence of northern and southern European Culex pipiens ( Cx. p.) pipiens mosquitoes for WNV across a gradient of temperatures. WNV infection and transmission rates were determined for two Cx. p . pipiens populations originating from The Netherlands and Italy, respectively. Mosquitoes were orally exposed by providing an infectious bloodmeal, or by injecting WNV (lineage 2) in the thorax, followed by 14-day incubation at 18, 23, or 28 °C. No differences in infection or transmission rates were found between the Cx. p. pipiens populations with both infection methods, but WNV transmission rates were significantly higher at temperatures above 18 °C. The absence of WNV outbreaks in northern Europe cannot be explained by differences in vector competence between Cx. p. pipiens populations originating from northern and southern Europe. This study suggests that low temperature is a key limiting factor for WNV transmission. [ABSTRACT FROM AUTHOR]