Next generation sequencing improves the resolution of detecting mixed host blood meal sources in field collected arboviral mosquito vectors.

Accurate knowledge of blood meal hosts of different mosquito species is critical for identifying potential vectors and establishing the risk of pathogen transmission. We compared the performance of Miseq next generation sequencing approach relative to conventional Sanger sequencing approach in identification of mosquito blood meals using genetic markers targeting the 12S rRNA and cytochrome oxidase I (COI) genes. We analysed the blood meals of three mosquito vector species (Aedes aegypti, Aedes simpsoni s.l. and Culex pipiens s.l.) collected outdoors, and compared the frequency of single- versus multiple-blood feeding. Single host blood meals were mostly recovered for Sanger-based sequencing of the mitochondrial 12S rRNA gene, whereas Miseq sequencing employing this marker and the COI marker detected both single and multiple blood meal hosts in individual mosquitoes. Multiple blood meals (two or more hosts) which mostly included humans were detected in 19%-22.7% of Ae. aegypti samples. Most single host blood meals for this mosquito species were from humans (47.7%-57.1%) and dogs (9.1%-19.0%), with livestock, reptile and rodent hosts collectively accounting for 4.7%-28.9% of single host blood meals. The frequency of two or more host blood meals in Ae. simpsoni s.l. was 26.3%-45.5% mostly including humans, while single host blood meals were predominantly from humans (31.8%-47.4%) with representation of rodent, reptile and livestock blood meals (18.2%-68.2%). Single host blood meals from Cx. pipiens s.l. were mostly from humans (27.0%-39.4%) and cows (11.5%-27.36%). Multiple blood meal hosts that mostly included humans occurred in 21.2%-24.4% of Cx. pipiens s.l. samples. Estimated human blood indices ranged from 53%-76% for Ae. aegypti, 32%-82% for Ae. simpsoni s.l. and 26%-61% for Cx. pipiens s.l. and were consistently lower for Sanger-based sequencing approach compared to Miseq-based sequencing approach. These findings demonstrate that Miseq sequencing approach is superior to Sanger sequencing approach as it can reliably identify mixed host blood meals in a single mosquito, improving our ability to understand the transmission dynamics of mosquito-borne pathogens.

Vector competence of Swedish Culex pipiens mosquitoes for Japanese encephalitis virus.

BACKGROUND: Japanese encephalitis virus (JEV) is an emerging mosquito-borne Orthoflavivirus that poses a significant public health risk in many temperate and tropical regions in Asia. Since the climate in some endemic countries is similar to temperate climates observed in Europe, understanding the role of specific mosquito species in the transmission of JEV is essential for predicting and effectively controlling the potential for the introduction and establishment of JEV in Europe. METHODS: This study aimed to investigate the vector competence of colonized Culex pipiens biotype molestus mosquitoes for JEV. The mosquitoes were initially collected from the field in southern Sweden. The mosquitoes were offered a blood meal containing the Nakayama strain of JEV (genotype III), and infection rates, dissemination rates, and transmission rates were evaluated at 14, 21, and 28 days post-feeding. RESULTS: The study revealed that colonized Swedish Cx. pipiens are susceptible to JEV infection, with a stable infection rate of around 10% at all timepoints. However, the virus was only detected in the legs of one mosquito at 21 days post-feeding, and no mosquito saliva contained JEV. CONCLUSIONS: Overall, this research shows that Swedish Cx. pipiens can become infected with JEV, and emphasizes the importance of further understanding of the thresholds and barriers for JEV dissemination in mosquitoes.

Long-term neurological and neurocognitive impairments after tick-borne encephalitis in Lithuania - a prospective study.

BACKGROUND: The aim of this study was to characterise long-term neurological and neurocognitive sequelae after tick-borne encephalitis (TBE) in adults. METHODS: 98 prospective consecutive TBE patients, classified by disease severity, were included. Immediate outcomes were evaluated with Glasgow Outcome Scale (GOS) and Rankin Scale (RS). After 6 and 18 months, long-term disability was evaluated using Modified Rankin Scale (MRS) and neurocognitive assessment was performed with Matrics Consensus Cognitive Battery (MCCB), measuring processing speed, attention/vigilance, working memory, verbal learning, visual learning, reasoning/problem solving and social cognition. The MCCB results were compared to healthy age, gender and education-matched controls. RESULTS: Mild, moderate, and severe TBE was diagnosed in 53.1%, 38.8%, and 8.2% of cases, respectively. At discharge, 25.5% of the patients had major or moderate impairments (GOS) and various levels of disability in 34.7% (RS). Up to 18 months from the onset of TBE, over 20% remained with slight to moderate disability (MRS). GOS, RS and MRS scores correlated with disease severity. At 6 months after the onset, TBE patients scored significantly lower than controls in processing speed, verbal, and visual learning. Two latter domains were significantly more impaired in patients with mild TBE. Patients aged 18-39 performed significantly worse in attention/vigilance and working memory, whereas aged 60+ in verbal learning. A year later, significant improvement was observed in six of seven cognitive domains. CONCLUSIONS: Long-term neurological sequelae persist in a substantial proportion of TBE patients with significant impairment in several cognitive domains, especially in younger patients and even after mild TBE.

Vertical transmission of chikungunya virus: a worldwide concern.

The Chikungunya Virus (CHIKV) already has endemic circulation in about 100 countries and the number of infected patients increases every year, due to the effectiveness of the vector and human universal susceptibility to infection. The virus can also be transmitted from mother to child, more frequently intrapartum. About 50 % of neonates with CHIKV symptoms will have neurodevelopmental delay. It is therefore an infection of worldwide concern with a great impact on people's quality of life. The objective of this work is to describe two cases of confirmed vertical transmission by chikungunya virus, one of them with intrauterine infection and death of the neonate. Neonates with vertical chikungunya infection may present with clinical sepsis in the first few days of life, which is why this is a very important diagnosis, especially during outbreaks of the infection.

Uncertainties Surrounding Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex.

Background: Madariaga virus (MADV), a member of the eastern equine encephalitis virus (EEEV) complex, circulates in Latin America and exhibits distinct evolutionary and ecological features compared to the North American EEEV. While published data have shed light on MADV ecology, several key aspects remain unknown. Methods: In this study, we compiled data on virus isolation, vector competence, and animal serology collected over six decades in Latin America to identify critical knowledge gaps on MADV transmission and ecology. Results: Specific vertebrate animals serving as amplifying hosts and the mosquito species acting as enzootic and epizootic vectors have not yet been identified. Other aspects that remain unclear are the virus current geographic distribution, the role of equines as hosts in epizootic cycles, and the full impact of MADV on human health in endemic regions. Conclusions: The numerous knowledge gaps surrounding MADV, its widespread distribution in Latin America, and its potential to cause severe disease in animals and humans emphasize the urgent need for increased research efforts, heightened awareness, and intensified surveillance towards this potential emerging threat.

Risk of infection with arboviruses in a healthy population in Pakistan based on seroprevalence.

Infectious diseases caused by arboviruses are a public health concern in Pakistan. However, the studies on data prevalence and threats posed by arboviruses are limited. This study investigated the seroprevalence of arboviruses in a healthy population in Pakistan, including severe fever with thrombocytopenia syndrome virus (SFTSV), Crimean-Congo hemorrhagic fever virus (CCHFV), Tamdy virus (TAMV), and Karshi virus (KSIV) based on a newly established luciferase immunoprecipitation system (LIPS) assays, and Zika virus (ZIKV) by enzyme-linked immunosorbent assays (ELISA). Neutralizing activities against these arboviruses were further examined from the antibody positive samples. The results showed that the seroprevalence of SFTSV, CCHFV, TAMV, KSIV, and ZIKV was 17.37%, 7.58%, 4.41%, 1.10%, and 6.48%, respectively, and neutralizing to SFTSV (1.79%), CCHFV (2.62%), and ZIKV (0.69%) were identified, as well as to the SFTSV-related Guertu virus (GTV, 0.83%). Risk factors associated with the incidence of exposure and levels of antibody response were analyzed. Moreover, co-exposure to different arboviruses was demonstrated, as thirty-seven individuals were having antibodies against multiple viruses and thirteen showed neutralizing activity. Males, individuals aged ≤40 years, and outdoor workers had high risk of exposure to arboviruses. All these results reveal the substantial risks of infection with arboviruses in Pakistan, and indicate the threat from co-exposure to multiple arboviruses. The findings raise the need for further epidemiologic investigation in expanded regions and populations and the necessity to improve health surveillance in Pakistan.

Fever and Rash.

Infectious causes of fever and rash pose a diagnostic challenge for the emergency provider. It is often difficult to discern rashes associated with rapidly progressive and life-threatening infections from benign exanthems, which comprise the majority of rashes seen in the emergency department. Physicians must also consider serious noninfectious causes of fever and rash. A correct diagnosis depends on an exhaustive history and head-to-toe skin examination as most emergent causes of fever and rash remain clinical diagnoses. A provisional diagnosis and immediate treatment with antimicrobials and supportive care are usually required prior to the return of confirmatory laboratory testing.

Prevalence of arboviruses in sickle cell disease patients from two different regions of Brazil, the North and Northeast

Sickle Cell Disease (SCD) is a hereditary disease characterized by extravascular and intravascular hemolysis and clinical variability, from mild pain to potentially life-threatening. Arboviruses include mainly Zika (ZIKV), Chikungunya (CHKV), and Dengue (DENV) virus, and are considered a public and social health problem. The present cross-sectional observational study aimed to investigate the prevalence of arbovirus infection in SCD patients from two Brazilian cities, Salvador and Manaus located in Bahia and Amazonas states respectively. A total of 409 individuals with SCD were included in the study, and 307 (75.06 %) patients tested positive for DENV-IgG, 161 (39.36 %) for ZIKV-IgG, and 60 (14.67 %) for CHIKV-IgG. Only one individual was positive for DENV-NS1 and another for DENV-IgM, both from Salvador. No individuals had positive serology for ZIKV-IgM or CHIKV-IgM. Arbovirus positivity by IgG testing revealed that the SCD group presented high frequencies in both cities. Interestingly, these differences were only statistically significant for ZIKV-IgG (p = 0.023) and CHIKV-IgG (p = 0.005) among SCD patients from Manaus. The reshaping of arbovirus from its natural habitat by humans due to disorderly urban expansion and the ease of international Mobility has been responsible for facilitating the spread of vector-borne infectious diseases in humans. We found the need for further studies on arboviruses in this population to elucidate the real association and impact, especially in acute infection. We hope that this study will contribute to improvements in the personalized clinical follow-up of SCD patients, identifying the influence of arbovirus infection in severe disease manifestations.

Local Economic Conditions Affect Aedes albopictus Management.

Invasive mosquitoes are an emerging public health issue, as many species are competent vectors for pathogens. We assessed how multiple environmental and socio-economic factors affected the engagement of municipalities in Italy (n = 7679) in actions against Aedes albopictus, an invasive mosquito affecting human health and well-being, between 2000 and 2020. We collected information about mosquito control from official documents and municipal websites and modeled the role played by multiple environmental and socioeconomic factors characterizing each municipality through the random forest algorithm. Municipalities are more prone to manage A. albopictus if more urbanized, in lowlands and with long infestation periods. Moreover, these variables are more predictive of management in municipalities with a high median income and thus more economic resources. Only 25.5% of Italian municipalities approved regulations for managing A. albopictus, and very few of them were in Southern Italy, the most deprived area of the country. Our findings indicate that local economic conditions moderate the effect of other drivers of mosquito control and ultimately can lead to better management of A. albopictus. If the management of invasive mosquitoes, or other forms of global change, is subjected to local economic conditions, economic inequalities will jeopardize the success of large-scale policies, also raising issues of environmental and climate justice.

Arbovirus - a threat to transfusion safety in Spain: a narrative review. / Arbovirus como amenaza para la seguridad transfusional en España: revisión narrativa.

Arboviruses represent a threat to transfusion safety for several reasons: the presence of vectors and the notification of autochthonous cases in our region, the recent increase in the number of cases transmitted through blood and/or blood component transfusion, the high prevalence rates of RNA of the main arboviruses in asymptomatic blood donors, and their ability to survive processing and storage in the different blood components. In an epidemic outbreak caused by an arbovirus in our region, transfusion centres can apply different measures: reactive measures, related to donor selection or arbovirus screening, and proactive measures, such as pathogen inactivation methods. The study of the epidemiology of the main arboviruses and understanding the effectiveness of the different measures that we can adopt are essential to ensure that our blood components remain safe.

Novel chikungunya and dengue vaccines-travel medicine applications.

Recent epidemics of dengue and chikungunya have highlighted the urgent need for vaccines to reduce the risk of infection in travellers. Given challenges tracking chikungunya outbreaks in real-time and the widespread resurgence of dengue, broader indications for the use of the new chikungunya and dengue vaccines should be considered.

Phagocyte-expressed glycosaminoglycans promote capture of alphaviruses from the blood circulation in a host species-specific manner.

The magnitude and duration of vertebrate viremia are critical determinants of arbovirus transmission, geographic spread, and disease severity-yet, mechanisms determining arbovirus viremia levels are poorly defined. Previous studies have drawn associations between in vitro virion-glycosaminoglycan (GAG) interactions and in vivo clearance kinetics of virions from blood circulation. From these observations, it is commonly hypothesized that GAG-binding virions are rapidly removed from circulation due to ubiquitous expression of GAGs by vascular endothelial cells, thereby limiting viremia. Using an in vivo model for viremia, we compared the vascular clearance of low and enhanced GAG-binding viral variants of chikungunya, eastern- (EEEV), and Venezuelan- (VEEV) equine encephalitis viruses. We find GAG-binding virions are more quickly removed from circulation than their non-GAG-binding variant; however individual clearance kinetics vary between GAG-binding viruses, from swift (VEEV) to slow removal from circulation (EEEV). Remarkably, we find phagocytes are required for efficient vascular clearance of some enhanced GAG-binding virions. Moreover, transient depletion of vascular heparan sulfate impedes vascular clearance of only some GAG-binding viral variants and in a phagocyte-dependent manner, implying phagocytes can mediate vascular GAG-virion interactions. Finally, in direct contrast to mice, we find enhanced GAG-binding EEEV is resistant to vascular clearance in avian hosts, suggesting the existence of species-specificity in virion-GAG interactions. In summary, these data support a role for GAG-mediated clearance of some viral particles from the blood circulation, illuminate the potential of blood-contacting phagocytes as a site for GAG-virion binding, and suggest a role for species-specific GAG structures in arbovirus ecology.

Persistence of IgG and neutralizing antibodies in Crimean-Congo hemorrhagic fever survivors.

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.

Ilheus Virus (ILHV) Resistance in Culex quinquefasciatus from the Northern Region of Brazil.

BACKGROUND: Orthoflavivirus ilheusense (ILHV) is a member of the Flaviviridae family. It was first isolated in 1944 from pools of Aedes serratus and Psorophora ferox mosquitoes; however, it has also been detected in species of the genus Culex, such as Cx. portesi and Cx. coronator. The objective of this study was to examine the vector competence of Cx. quinquefasciatus mosquitoes to ILHV infection and the subsequent transmission of the virus through their saliva during feeding on blood. METHODS: F1 generation females of Cx. quinquefasciatus (Ananindeua/PA) were orally infected with goose blood infected with strain BeH7445, and body, head and saliva samples were analyzed at 7, 14, and 21 dpi using the techniques of virus isolation in cells and indirect immunofluorescence. RESULTS: The presence of ILHV was not detected in the body and head samples of Cx. quinquefasciatus females at any of the three dpi's analyzed, indicating that the lineage of mosquitoes analyzed was resistant to ILHV. CONCLUSIONS: According to the results obtained in this study, the species Cx. quinquefasciatus proved resistant to ILHV, regardless of the virus titers to which it was exposed, which suggests the possibility that this species does not act as a vector in the ILHV transmission cycle.

Detection and quantification of natural Wolbachia in Aedes aegypti in Metropolitan Manila, Philippines using locally designed primers.

Background: The Philippines bears health and economic burden caused by high dengue cases annually. Presently, the Philippines still lack an effective and sustainable vector management. The use of Wolbachia, a maternally transmitted bacterium, that mitigate arbovirus transmission has been recommended. Cytoplasmic incompatibility and viral blocking, two characteristics that make Wolbachia suitable for vector control, depend on infection prevalence and density. There are no current Wolbachia release programs in the Philippines, and studies regarding the safety of this intervention. Here, we screened for Wolbachia in Aedes aegypti collected from Metropolitan Manila, Philippines. We designed location-specific primers for qPCR to test whether this improved Wolbachia detection in Ae. aegypti. We explored if host sex and Wolbachia strain could be potential factors affecting Wolbachia density. Methods: Ae. aegypti mosquitoes (n=429) were screened for natural Wolbachia by taqman qPCR using location-specific Wolbachia surface protein primers (wspAAML) and known 16S rRNA primers. Samples positive for wspAAML (n=267) were processed for Sanger sequencing. We constructed a phylogenetic tree using IQ-TREE 2 to further characterize Wolbachia present in the Philippine Ae. aegypti. We then compared Wolbachia densities between Wolbachia groups and host sex. Statistical analyses were done using GraphPad Prism 9.0. Results: Wolbachia prevalence for 16S rRNA (40%) and wspAAML (62%) markers were high. Wolbachia relative densities for 16S rRNA ranged from -3.84 to 2.71 and wspAAML from -4.02 to 1.81. Densities were higher in male than female mosquitoes. Wolbachia strains detected in Ae. aegypti clustered into supergroup B. Some 54% (123/226) of these sequences clustered under a group referred to here as "wAegML," that belongs to the supergroup B, which had a significantly lower density than wAegB/wAlbB, and wAlbA strains. Conclusion: Location-specific primers improved detection of natural Wolbachia in Ae. aegypti and allowed for relative quantification. Wolbachia density is relatively low, and differed between host sexes and Wolbachia strains. An economical way of confirming sporadic or transient Wolbachia in Ae. aegypti is necessary while considering host sex and bacterial strain.

A brief description of the epidemiology of dengue in Dili, Timor-Leste, 2018-2022.

Abstract: Dengue virus (DENV) infection causes 390 million infections per year and 40,000 deaths globally. It is endemic in many countries in Asia, Africa, the Americas, the Caribbean, and Oceania. Dengue is endemic in Timor-Leste year-round, but peak transmission occurs during the rainy season. We briefly describe the epidemiology of DENV in the Municipality of Dili between 2018 and 2022. There were 6,234 cases notified, with a mean annual incidence rate of 330 cases per 100,000 population. There were 55 deaths (case fatality rate 0.9%). The peak annual incidence (3,904 cases) occurred in 2022 after an outbreak was declared in January of that year; this outbreak included 760 cases of dengue haemorrhagic fever and 35 deaths. The number of outbreak cases requiring hospital treatment exceeded the usual capacity, but facilities established for coronavirus disease 2019 (COVID-19) isolation and treatment were repurposed to meet this demand. Existing strategies of vector control, minimising breeding sites and promoting early presentation for treatment should continue, as should the utilisation of surveillance systems and treatment facilities established during the COVID-19 pandemic. However, dengue incidence remains high, and other dengue control strategies-including the deployment of Wolbachia-infected mosquitoes-should be considered in Timor-Leste.

The first confirmed outbreak of chikungunya reported in Timor-Leste, 2024.

Abstract: Timor-Leste is a mountainous, half-island nation with a population of 1.3 million, which shares a land border with Indonesia and is 550 km from Darwin, Australia. Since independence in 2002, Timor-Leste has achieved significant development; however, high levels of poverty remain. Chikungunya virus (CHIKV) is endemic in over 100 countries in Africa, Asia, Europe and in the Americas. It is transmitted by the bite of infected Aedes aegypti or Ae. albopictus mosquitoes, which are present in Timor-Leste and which contribute to annual rainy-season dengue virus (DENV) outbreaks. Symptomatic people typically suffer from acute onset of fever, usually accompanied by severe arthritis or arthralgia. Joint pain can be debilitating for several days, and may sometimes last for weeks, months or years. Unlike DENV infection which has significant mortality, most people recover completely. Between 2002 and 2023, there were 26 cases of CHIKV notified in Australia who acquired their infection in Timor-Leste; however, laboratory testing capability for CHIKV in Timor-Leste only became available in 2021 using polymerase chain reaction (PCR). The first locally diagnosed case was notified in November 2023. In January 2024, an outbreak of CHIKV was recognised in Timor-Leste for the first time, with 195 outbreak cases reported during 1-31 January 2024; all were PCR positive. There were no cases hospitalised, and no deaths. The median age of cases was 17 years (range 1-76 years); 51% were males. Cases were reported across the country; most (88/195) were from Dili, although the highest incidence was seen in the neighbouring municipality of Ermera (monthly incidence rate of 58.8 cases per 100,000 population). This first reported outbreak of CHIKV in Timor-Leste highlights the need for improved mosquito-borne illness control and response strategies, including minimising breeding sites and promoting early presentation for treatment and differential diagnosis from DENV, and consideration of the deployment of Wolbachia-infected mosquitoes, particularly as they have shown to reduce the transmission of CHIKV, DENV and Zika virus, all of which pose threats in Timor-Leste.

Cell fusing agent virus rarely transmits vertically in artificially infected laboratory-colonized Aedes aegypti mosquitoes.

BACKGROUND: Vertical transmission (VT) of arboviruses (arthropod-borne viruses) can serve as an essential link in the transmission cycle during adverse environmental conditions. The extent of VT among mosquito-borne arboviruses can vary significantly among different virus families and even among different viruses within the same genus. For example, orthobunyaviruses exhibit a higher VT rate than orthoflaviviruses and alphaviruses. Mosquitoes are also the natural hosts of a large number of insect-specific viruses (ISV) that belong to several virus families, including Bunyaviridae, Flaviviridae, and Togaviridae. Cell fusing agent virus (CFAV), an insect-specific orthoflavivirus, displays higher VT rates than other dual-host orthoflaviviruses, such as Zika and dengue viruses. High VT rates require establishment of stabilized infections in the germinal tissues of female vectors. To delve deeper into understanding the mechanisms governing these differences in VT rates and the establishment of stabilized infections, the ovary infection patterns and VT of Zika virus (ZIKV) and CFAV were compared. METHODS: Laboratory colonized Aedes aegypti females were infected with either ZIKV or CFAV by intrathoracic injection. Ovary infection patterns were monitored by in situ hybridization using virus-specific probes, and VT was determined by detecting the presence of the virus among the progeny, using a reverse-transcription quantitative polymerase chain reaction (PCR) assay. RESULTS: Both ZIKV and CFAV infect mosquito ovaries after intrathoracic injection. Infections then become widespread following a non-infectious blood meal. VT rates of ZIKV are similar to previously reported results (3.33%). CFAV, on the contrary transmits vertically very rarely. VT was not observed in the first gonotrophic cycle following intrathoracic injection, and only rarely in the second gonotrophic cycle. VT of CFAV is mosquito population independent, since similar results were obtained with Aedes aegypti collected from two different geographic locations. CONCLUSIONS: Although CFAV infects mosquito ovaries, the occurrence of VT remains infrequent in artificially infected Ae. aegypti, despite the observation of high VT rates in field-collected mosquitoes. These results suggest that infections of insect-specific viruses are stabilized in mosquitoes by some as yet unidentified mechanisms.

The High Capacity of Brazilian Aedes aegypti Populations to Transmit a Locally Circulating Lineage of Chikungunya Virus.

The incidence of chikungunya has dramatically surged worldwide in recent decades, imposing an expanding burden on public health. In recent years, South America, particularly Brazil, has experienced outbreaks that have ravaged populations following the rapid dissemination of the chikungunya virus (CHIKV), which was first detected in 2014. The primary vector for CHIKV transmission is the urban mosquito species Aedes aegypti, which is highly prevalent throughout Brazil. However, the impact of the locally circulating CHIKV genotypes and specific combinations of local mosquito populations on vector competence remains unexplored. Here, we experimentally analyzed and compared the infectivity and transmissibility of the CHIKV-ECSA lineage recently isolated in Brazil among four Ae. aegypti populations collected from different regions of the country. When exposed to CHIKV-infected AG129 mice for blood feeding, all the mosquito populations displayed high infection rates and dissemination efficiency. Furthermore, we observed that all the populations were highly efficient in transmitting CHIKV to a vertebrate host (naïve AG129 mice) as early as eight days post-infection. These results demonstrate the high capacity of Brazilian Ae. aegypti populations to transmit the locally circulating CHIKV-ECSA lineage. This observation could help to explain the high prevalence of the CHIKV-ECSA lineage over the Asian lineage, which was also detected in Brazil in 2014. However, further studies comparing both lineages are necessary to gain a better understanding of the vector's importance in the epidemiology of CHIKV in the Americas.

Epidemiologic Survey of Crimean-Congo Hemorrhagic Fever Virus in Suids, Spain.

We conducted a cross-sectional study in wild boar and extensively managed Iberian pig populations in a hotspot area of Crimean-Congo hemorrhagic fever virus (CCHFV) in Spain. We tested for antibodies against CCHFV by using 2 ELISAs in parallel. We assessed the presence of CCHFV RNA by means of reverse transcription quantitative PCR protocol, which detects all genotypes. A total of 113 (21.8%) of 518 suids sampled showed antibodies against CCHFV by ELISA. By species, 106 (39.7%) of 267 wild boars and 7 (2.8%) of 251 Iberian pigs analyzed were seropositive. Of the 231 Iberian pigs and 231 wild boars analyzed, none tested positive for CCHFV RNA. These findings indicate high CCHFV exposure in wild boar populations in endemic areas and confirm the susceptibility of extensively reared pigs to CCHFV, even though they may only play a limited role in the enzootic cycle.