West Nile Virus Cases Research Articles

Early detection of West Nile Virus mosquitoes and cases in Frisco and Dallas in 2019 using DNA &RNA testing and Climatic prediction with Math lab followed by Descriptive statistical analysis using R-programming

West Nile Virus is a mosquito borne disease that is initially caused in continental US that leads to neurological disease and death. There exists no vaccine or particular antiviral treatment for WNV.The mosquitoes become infected when they bite the infected birds. WNV is confined to the family Flaviviridae containing single stranded positive RNA with 11kb length. The purpose of this paper is to study WNV human cases and WNV positive mosquito traps in Frisco 75035 from Sep-Oct 2019. Also, the paper aims in explaining the current CDC data on WNV cases in detail using descriptive computer statistical analysis method. The data describes the current 2019 WNV neuro cases, WNV non-neuro cases, Death and presumptive viremic blood donors. According to (DSHS, 2019), there is no WNV cases reported yet in Frisco 2019 and one positive WNV case in Dallas county. According to CDC (2019), out of total 777, 98 were presumptive viremic blood donors, 504 was neuro-invasive cases, 273 were non-neuro-invasive cases, and 39 death was reported. Arizona and Colorado have the highest number of WNV Neuro invasive and Non-neuro-invasive cases of 132 and 60. This summary statistics reveals Neuro invasive cases have higher mean of 11.45 to non-neuro-invasive with 6.205. On the T-test it reveals at 95 % confidence level (P=0.007681) a significant difference in total cases versus the presumptive blood donors. It also represents more positive relationship on the scatter plots. According to Texas Department of state Health and Human Services (2019), reported human cases of reportable West Nile Disease of 19; out of which West Nile encephalitis is 15 and West Nile fever is 4. This shows that in Texas there is a drastic reduction of West Nile disease cases reported in 2019 related to good surveillance plans. This review summarizes descriptive statistical analysis of 2019 WNV cases which has shown a new increase in Presumptive viremic blood donors which is the hall mark of this review. Finally, the paper has completed a climatic niche prediction model using Math lab computer software for the future prediction of WNV positive mosquitoes using climatic conditions like high temperature, low temperature, humidity, rainfall, and precipitation.

Characterisation of the cerebrospinal fluid of horses with West Nile virus neuroinvasive disease.

West Nile virus (WNV) is a zoonotic arbovirus transmitted by mosquitoes between wild birds (natural hosts) and other vertebrates. Horses and humans are incidental, dead-end hosts, but can develop severe neurological disorders. Owing to the close contact of cerebrospinal fluid (CSF) with the extracellular fluid of the brain, the analysis of CSF composition can reflect central nervous system (CNS) impairments enabling the diagnosis and understanding of various neurodegenerative CNS disorders. Our objective was to compare the findings from the CSF samples of horses with neuroinvasive WNV infection with those of healthy controls. We compared findings from fifteen CSF samples of 13 horses with acute WNV encephalomyelitis with those of 20 healthy controls. Protein, particular enzymes and ions, glucose and lactate showed abnormal levels in a significant number of WNV cases. None of the six horses with elevated glucose concentrations survived. Rather neutrophilic than mononuclear pleocytosis was identified with WNV infection. Neutrophils probably play a role in the development of inflammatory response and brain damage. Although elevated glucose levels reliably predicted the outcome, they might be the consequence of increased plasma levels and reflect general stress rather than CNS pathophysiology. The CSF findings of WNV encephalomyelitis patients are non-specific and variable but facilitate the differential diagnosis.

A Comparison of Adult Mosquito Trapping Methods to Assess Potential West Nile Virus Mosquito Vectors in Greece during the Onset of the 2018 Transmission Season.

West Nile virus (WNV) threatens the health of humans and equines worldwide. Culex (Cx.) pipiens complex mosquitoes are major vectors but numerous other species have been implicated. Due to variations in blood-feeding behaviour, Cx. pipiens biotypes and hybrids influence transmission, from enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and equines. In this study, mosquitoes were collected in May–June 2018 during the early period of the transmission season from two regional units of Greece, where WNV cases had been reported in the previous four years (Palaio Faliro and Argolida). A total of 1062 mosquitoes were collected with Biogents Sentinel 2 traps collecting both a greater number of all mosquito species and the Cx. pipiens complex than CDC miniature light traps or Heavy Duty EVS traps. Molecular identification confirmed additional species including Aedes albopictus. The proportion of Cx. pipiens biotypes in Palaio Faliro was 54.5% pipiens, 20.0% molestus and 25.5% hybrids. In Argolida, the collection comprised 68.1% pipiens biotype, 8.3% molestus biotype and 23.6% hybrids. Screening resulted in WNV detection in three females of the pipiens biotype and in one hybrid. As hybrids play a role in spill-over transmission, these findings highlight the importance of entomological surveillance programs incorporating molecular xenomonitoring as an early warning before human cases at the onset of the transmission season.

The drivers of West Nile virus human illness in the Chicago, Illinois, USA area: Fine scale dynamic effects of weather, mosquito infection, social, and biological conditions.

West Nile virus (WNV) has consistently been reported to be associated with human cases of illness in the region near Chicago, Illinois. However, the number of reported cases of human illness varies across years, with intermittent outbreaks. Several dynamic factors, including temperature, rainfall, and infection status of vector mosquito populations, are responsible for much of these observed variations. However, local landscape structure and human demographic characteristics also play a key role. The geographic and temporal scales used to analyze such complex data affect the observed associations. Here, we used spatial and statistical modeling approaches to investigate the factors that drive the outcome of WNV human illness on fine temporal and spatial scales. Our approach included multi-level modeling of long-term weekly data from 2005 to 2016, with weekly measures of mosquito infection, human illness and weather combined with more stable landscape and demographic factors on the geographical scale of 1000m hexagons. We found that hot weather conditions, warm winters, and higher MIR in earlier weeks increased the probability of an area of having a WNV human case. Higher population and the proportion of urban light intensity in an area also increased the probability of observing a WNV human case. A higher proportion of open water sources, percentage of grass land, deciduous forests, and housing built post 1990 decreased the probability of having a WNV case. Additionally, we found that cumulative positive mosquito pools up to 31 weeks can strongly predict the total annual human WNV cases in the Chicago region. This study helped us to improve our understanding of the fine-scale drivers of spatiotemporal variability of human WNV cases.

Evaluation of a West Nile virus risk-assessment tool used at a local health unit

In Ontario, public health units collect surveillance data on vector-borne diseases (VBD) to determine emerging trends and develop VBD management strategies. Risk-assessment tools that are simple and easily applied can provide public health practitioners with objective evaluations of the risk of West Nile virus (WNV) activity in their jurisdiction. This study was conducted to evaluate an existing WNV risk-assessment tool used by a public health unit in southern Ontario. The purpose of this study was to: (i) describe the trends for WNV in mosquito and human cases in the Region of Peel, Ontario, Canada, and (ii) investigate the ability of the risk-assessment tool to predict positive human cases and positive mosquito traps in the following weeks. Data were collected from 2011 to 2016 and analysed using simple descriptive statistics and Fisher’s exact tests. This study found the tool includes variables that are not significant in predicting WNV activity in the following weeks. The current tool should be revised to remove variables that are not significant in predicting risk and add additional variables that have been shown to be effective predictors in other studies, such as rainfall and human WNV cases in the previous year.

Fever, Myalgia, and Headache Progressing to Confusion: A Case of Neuroinvasive West Nile Virus in the Older Adult

Fever, Myalgia, and Headache Progressing to Confusion: A Case of Neuroinvasive West Nile Virus in the Older Adult

Can local risk of West Nile virus infection be predicted from previous cases? A descriptive study in Quebec, 2011-2016.

This study aimed at (1) describing the local risk of West Nile virus (WNV) infection in humans based on previous case reports and (2) investigating the spatial clustering of cases in the five most affected administrative regions of Quebec, Canada, for the 2011-2016 period. Human WNV cases declared to the Ministry of Health and Social Services of Quebec(Ministère de la santé et des services sociaux, MSSS) were retrieved. Incidence risk by age and sex was calculated for the study period. The yearly and monthly occurrence of cases in geographical units (GUs) was described and the probability of observing cases in a GU with cases reported in the previous year or month was assessed. Moran's I was used to assess global clustering across the study area. Spatial clusters were identified by the Kulldorff scan statistic. A total of 261 WNV cases were declared to the MSSS between 2011 and 2016 in the study area. Overall, a low percentage of GU with cases reported had additional cases reported over the next month or year. Global spatial clustering was weak but statistically significant (p < 0.05) for 2012 and 2015. For these two years, spatial clusters of high-risk GUs were identified. Results underline the challenge of predicting the distribution of WNV incidence risk in Quebec based on previous occurrence of human cases. Ongoing research with high spatial resolution entomological data is still necessary to understand the spatial distribution of risk at a local scale.

Locally temperature - driven mathematical model of West Nile virus spread in Germany

West Nile virus (WNV) is an arthropod-borne virus (arbovirus) transmitted by the bites of infected mosquitoes. WNV can also infect horses and humans, where it may cause serious illness and can be fatal. Birds are the natural reservoir, and humans, equines and probably other mammals are dead-end hosts. In 2018, WNV occurred for the first time in Germany, affecting birds and horses. Seroconversion of an exposed veterinarian has also been reported. It is therefore of importance to evaluate the circumstances, under which WNV may establish in Germany as a whole or in particular favourable regions.In our current work, we formulate a dynamic model to describe the spreading process of West Nile virus in the presence of migratory birds. To investigate the possible role of migratory birds in the dissemination of WNV in Germany, we include the recurring presence of migratory birds through a mechanistic ordinary differential equations (ODE) model system. We also perform a sensitivity analysis of the infection curves. Seasonal impacts are also taken into consideration. As result, we present an analytical expression for the basic reproduction number R0. We find that after introducing WNV into Germany, R0 will be above the critical value in many regions of the country. Furthermore, we observe that in the south of Germany, the disease reoccurs in the following season after the introduction. We include a potential distribution map associated with WNV cases in Germany to illustrate our findings in a spatial scale.

West Nile virus activity in United States blood donors and optimizing detection strategies: 2014-2018.

Rare transfusion-transmitted West Nile virus (WNV) cases usually occur due to gaps in testing involving converting to more sensitive nucleic acid testing (NAT) formats (referred to as triggering). Using data from 2014 to 2018, we investigated a strategy used to increase detection early in the triggering period and reviewed its yield as the individual donation (ID)-NAT geographic area was decreased. Mini-pool-NAT transitioned to ID-NAT following triggering based on one WNV NAT-reactive donation (having an elevated signal, repeat reactive, or in an area with WNV ongoing activity). ID-NAT-triggered geographic areas included an entire state (2014-2017) or collections within a 50-mile radius of the triggering donor's residential zip code (2018). During the MP- to ID-NAT transition, donation samples were retrieved and tested by ID-NAT for those with results not yet released (referred to as in-process testing). Reactive sample confirmation was performed by repeat NAT of an independent sample or antibody testing. ID-NAT included 3.2 million donations of more than 25 million tested year-round, resulting in 684 confirmed positives; all confirmed-positive donations occurred from June to December (0.64/10,000). Overall, 52% (358/684) required ID-NAT for detection, including 68 (19%) antibody negatives. Ten of 19 (53%) identified in-process were ID-NAT-only detectable, including four antibody negatives, or approximately 1 per year (2.8% of ID-NAT-only detectable). With reduced triggering geography, 12 of 19 (63%) were not identified (including 6/10 ID-NAT-only detectable, and 2/4 ID-NAT-only detectable/antibody negative). WNV NAT's utility is between June-December; however, abandoning testing outside of this time may increase risk. While in-process testing identified approximately one ID-NAT-only detectable (antibody-negative) donation per year, reducing the geographic triggered area decreased its effectiveness.

Entomological Data and Detection of West Nile Virus in Mosquitoes in Greece (2014-2016), Before Disease Re-Emergence in 2017.

West Nile virus (WNV) cases were seasonally recorded in humans and animals in Greece, from 2010 to 2014, and circulation of the virus was detected in different Regional Units of the country. Small scale entomological surveillance activities were carried out by several regions and regional units in Greece, during 2014-2016, with the participation of subcontractors for the vector control programs aiming to record presence/absence of mosquito species, and monitor and control mosquito populations. Mosquito traps were placed in rural and urban sites; specimens were collected, morphologically characterized, and pooled by date of collection, location, and species types. Mosquito pools containing Culex pipiens, Aedes caspius, and Aedes albopictus were examined for the presence of WNV and positive pools were detected in different areas of the country. Sequencing of a selected number of amplicons revealed WNV lineage 2 partial NS5 gene sequences. In this study, we present data on the mosquito species composition in the areas of study and WNV detection from several parts of Greece, in 6, 11, and 26 mosquito pools corresponding to the years 2014, 2015, and 2016, respectively. A total of 15 WNV human infections were reported to the public health authorities of the country in 2014, whereas no human cases were detected for 2015-2016. Taking into consideration the complex epidemiological profile of WNV and unforeseen changes in its circulation, re-emergence of WNV human cases in Greece was possible and expected, thus rendering surveillance activities imperative.

West Nile virus infections in France, July to November 2018

Abstract In July 2018, one autochthonous case of West Nile virus (WNV) infection was identified in Nice, Provence-Alpes-Côte d’Azur (Paca). We investigated to determine the potential place of infection and the extent of viral circulation in the area, in order to guide control and preventive measures. In affected areas, we raised awareness of health professionals on WNV infections, substance of human origin safety relied on nucleic acid testing for WNV and on deferral of blood donors indicating minimum one night of stay in the areas for 28 days. Equine, wild bird and entomologic surveillance activities were reinforced. The human arboviruses national reference laboratory (NRL) retrospectively tested samples from hospitalized individuals from June 1st with meningitis and encephalitis around Nice. We tested negative suspected autochthonous cases of chikungunya and dengue infections notified since July in Paca and presenting WNV compatible symptoms. Measures were adapted along identification of additional cases. We identified 27 autochthonous cases, with onset of symptoms between July 7th and November 12th: 24 in Paca, 2 in Corsica and 1 in Occitanie. Seven cases presented neuroinvasives symptoms, 18 flu-like symptoms and 2 were asymptomatic. One blood donation and 2 organs tested positive for WNV. The animal NRL identified 13 equine cases (1 in Paca, 5 in Corsica and 7 in Occitanie) and 4 infected raptors with nervous symptoms (3 in Paca and 1 in Corsica). Genomic characterization of the virus identified a strain belonging to the lineage 2 among 2 raptors. No virus was found in mosquitoes captured in affected areas. Since 2000, six episodes of WNV transmission were reported in France but none with this extent. For the first time, the lineage 2, circulating in Italy and other European countries, was isolated in France which might be changing epidemiological situation. Therefore, surveillance activities should be revised in order to promptly secure blood products. Key messages We describe the most important episode of West Nile Virus transmission identified in humans in France. In 2018, West Nile virus lineage 2 was isolated for the first time in France which might change the epidemiological situation in the country.

Environmental and Sociological Factors Associated with the Incidence of West Nile Virus Cases in the Northern San Joaquin Valley of California, 2011-2015.

Environmental and socioeconomic risk factors associated with the incidence of human West Nile virus (WNV) cases were investigated in the Northern San Joaquin Valley region of California, a largely rural area. The study included human WNV cases from the years 2011 to 2015 in the three-county area of San Joaquin, Stanislaus, and Merced Counties, and used census tracts as the unit of analysis. Environmental factors included temperature, precipitation, and WNV-positive mosquito pools. Socioeconomic variables included age, housing age, housing foreclosures, median income, and ethnicity. Chi-square independence tests were used to examine whether each variable was associated with the incidence of WNV cases using data from the three counties combined. In addition, negative binomial regression revealed that the environmental factors of temperature and precipitation were the strongest predictors of the incidence of human WNV cases, while the socioeconomic factor of ethnicity was a significant predictor as well, and is a factor to consider in prevention efforts. Source reduction of mosquito breeding sites and targeted prevention and education remain key in reducing the risk associated with WNV.

Recent rapid changes in the spatio-temporal distribution of West Nile Neuro-invasive Disease in Italy.

In Italy, the first human case of West Nile Virus (WNV) infection was reported in 2008 and, since then, the number of cases has been steadily increasing. In this study, we describe the temporal and spatial pattern of WNV infection risk among humans in Italy, focusing on the human cases of West Nile Neuro-invasive Disease (WNND) observed between 2008 and 2017. Incidence rates are estimated for each year and province under study. The incidence temporal trend is estimated using Poisson regression, and a spatio-temporal cluster detection analysis is performed to detect high-risk areas. In total, 231 WNND cases were notified in Italy between 2008 and 2017. The annual incidence rates increased during the study period (annual percentage change: 11.7%; 95%CI: -0.9%; 26.1%). A geographical spread of the disease was observed during the study period throughout Northern Italy, with an increasing number of affected provinces. Provinces close to the Po River (the main river in the north of Italy) and the Oristano province (in the Sardinia Island) experienced the highest incidence rates during the study period. Our study shows a gradual, but rapid spread of WNND across Northern Italy from east to west and suggests the hypothesis that provinces close to Po River might present ecological and climatic conditions favourable to the virus circulation.

Economic Burden of West Nile Virus Disease, Quebec, Canada, 2012-2013.

The economic burden of West Nile virus (WNV) infection is not known for Canada. We sought to describe the direct and indirect costs of WNV infection in the province of Quebec, Canada, up to 2 years after onset of signs and symptoms. We conducted a retrospective cohort study that included WNV cases reported during 2012 and 2013. For 90 persons infected with WNV, persons with encephalitis accounted for the largest proportion of total cost: a median cost of $21,332 per patient compared with $8,124 for West Nile meningitis (p = 0.0004) and $192 for West Nile fever (p<0.0001). When results were extrapolated to all reported WNV patients, the estimated total cost for 124 symptomatic cases was ≈$1.7 million for 2012 and that for 31 symptomatic cases was ≈$430,000 for 2013. Our study provides information for the government to make informed decisions regarding public health policies and infectious diseases prevention and control programs.

Clinical Spectrum of West Nile Virus Neuroinvasive Disease.

West Nile virus (WNV) is the most common arbovirus infection in the United States. The diagnosis requires consideration of not only a broad spectrum of presenting symptoms, ranging from a mild febrile illness to severe encephalitis and acute flaccid paralysis, but also public health risk factors and seasonality. There is no approved targeted therapy for WNV, so treatment relies on supportive care, management of neurologic sequelae and airway, treatment of other systems including the eye, and aggressive rehabilitation. Here, we describe a series of 3 cases of WNV encountered in September 2018 at one institution. First, we describe a case of WNV encephalitis with worsened dyskinesias and a relatively good recovery. Second, we describe a severe WNV encephalitis with overlying motor neuron involvement with a poor outcome. Finally, we describe a case of a WNV meningitis with significant bilateral chorioretinitis, an underappreciated complication of WNV infections. Through these cases, we review the epidemiology of WNV, risk factors for infection, the neurologic sequalae and long-term outcomes, and the importance of recognizing ocular involvement to prevent ophthalmologic complications.

Extraordinary increase in West Nile virus cases and first confirmed human Usutu virus infection in Hungary, 2018.

BackgroundDuring the 2018 WNV transmission season, similarly to other endemic areas in Europe, a large number of human West Nile virus (WNV) infections were reported in Hungary.AimsWe summarise the epidemiological and laboratory findings of the 2018 transmission season and expand experiences in flavivirus differential diagnostics.MethodsEvery patient with clinical suspicion of acute WNV infection was in parallel tested for WNV, tick-borne encephalitis virus and Usutu virus (USUV) by serological methods. Sera, whole blood and urine samples were also tested for the presence of viral nucleic acid.ResultsUntil the end of December 2018, 215 locally acquired and 10 imported human WNV infections were notified in Hungary. All reported cases were symptomatic; most of them exhibited neurological symptoms. In a large proportion of tested individuals, whole blood was the most appropriate sample type for viral nucleic acid detection, but because whole blood samples were not always available, testing of urine samples also extended diagnostic possibilities. In addition, the first human USUV infection was confirmed in 2018 in a patient with aseptic meningitis. Serological cross-reactions with WNV in different serological assays were experienced, but subsequent molecular biological testing and sequence analysis identified Europe lineage 2 USUV infection.ConclusionCareful interpretation and simultaneous application of different laboratory methods are necessary to avoid misdiagnosis of human USUV cases. Expansion of the laboratory-confirmed case definition criteria for detection of viral RNA in any clinical specimens to include urine samples could increase diagnostic sensitivity.

Phenotypic insecticide resistance in arbovirus mosquito vectors in Catalonia and its capital Barcelona (Spain).

A range of mosquito species that belong to the Culicidae family are responsible for the worldwide transmission of infectious arboviral diseases such as dengue fever, Zika, West Nile fever and Chikungunya fever. Spain is at risk of arbovirus outbreaks, as various arboviral diseases are frequently introduced and it has established competent vector populations. Autochthonous human cases of West Nile virus have been reported infrequently since 2004, and since October 2018 three autochthonous human case of dengue fever have been confirmed. In response to an outbreak of any arboviral disease, space spraying or fogging will be implemented to control adult mosquito populations. To ensure adulticiding is cost-effective, the insecticide susceptibility status of vectors throughout Catalonia, an autonomous region in north-eastern Spain, was assessed through standardized WHO tube and CDC bottle bioassays. All Culex pipiens populations tested were resistant to at least one of the pyrethroids tested, whereas Aedes albopictus populations were susceptible to all pyrethroids tested. More detailed studies on the Cx. pipiens populations from the Barcelona area (the capital and largest city of Catalonia) revealed resistance to all four classes of public health insecticides available (pyrethroids, carbamates, organophosphates and organochlorides). All Ae. albopictus populations were susceptible to those classes, except for one of the tests performed with pirimiphos-methyl (an organophosphate). Pyrethroids are currently the first line chemical class to be used in space spray operations in response to an outbreak of an arboviral disease. While pyrethroids can be effective in reducing Ae. albopictus populations, this class may not be effective to control Cx. pipiens populations.

West Nile Virus Seroprevalence Among Blood Donors in Hungary.

Background and Objectives: West Nile virus (WNV) is one of the most important viral zoonotic infections in Hungary; however, no transfusion-transmitted WNV infections have been confirmed so far. In 2016, the number of clinical cases of WNV reported was 44, but the seasonal WNV screening of whole-blood donors has not yet been implemented. Our aims were to assess the WNV RNA reactivity and the prevalence of WNV-specific antibodies in the samples of blood donors collected in 2016. Materials and Methods: WNV RNA with Cobas TaqScreen and anti-WNV antibody determination from plasma samples of 2112 donors was performed. Cross-reactivity to tick-borne encephalitis virus was excluded. WNV neutralization test was used for the confirmation of anti-WNV IgG reactive results, and the presence of anti-WNV IgM antibodies was also determined. Results: None of the samples showed WNV RNA reactivity. The total weighted anti-WNV IgG prevalence was 2.34% (95% confidence interval 1.65-3.03), and in addition, three donors were found to be IgM positive. There was a comparable tendency between the data of WNV seroprevalence and cumulative incidence in six out of seven statistical regions in Hungary. Conclusion: Our results show a comparable data with publications that estimated the WNV seroprevalence in some other European endemic areas. As protective measures, both the 30-day deferral of blood donors who spent at least 24 h in WNV-exposed areas and the exclusion of affected Hungarian territories from blood donation are enforced by the Hungarian National Blood Transfusion Service. Our study is the first comprehensive serological survey to obtain actual data about WNV seroprevalence in the Hungarian human population.

Surveillance on Arboviral Infections in Georgia by using One Health Approach

ObjectiveIdentify cases of West Nile virus in Black Sea region of Georgia through active surveillance.IntroductionArbovirus infections are causing enormous global burden, while their geographic distribution expands and affects new regions and areas. West Nile virus (WNV), one of the most important pathogens among arboviruses, was historically associated with causing mild febrile illness, however, after the outbreak occurred in the North America, which caused more severe illness, it has received wider recognition. It is believed that the disease can reemerge after a hiatus of several years, and affect new territories, which has happened in 2018 in Greece, with 31 dead among 271 infections by the end of September. In Georgia, there is a lack of clinical suspicion on WNV because of the low awareness among medical society, and the existent passive surveillance system seems to be improved.MethodsIn order to assess the situation in Georgia, medical histories and Electronic Integrated Disease Surveillance System (EIDSS) database was studied, and active surveillance has been conducted with the following case selection criteria: residence - Black Sea region; diagnosis - fever of unknown origin (FUO). Enzyme-linked immunosorbent assay (ELISA) was performed. Mosquitoes were obtained by using light traps and aspirators, and are now being studied. Medical personnel was trained on using WNV case definition.ResultsThree laboratory positive cases were identified from 36 suspected cases. Two of them were males (66%). Age distribution – 28-35 y.o. All three cases resided in the city of Batumi in the Adjara region. A total of 572 mosquitoes were obtained. According to preliminary analysis, the species include: Culex pipiens, Aedes albopictus, A. aegypti, A. caspius, A. geniculatus, Anopheles claviger.ConclusionsThe preliminary data suggests that the burden of WNV in Georgia should be studied with more in-depth approaches and with just passive surveillance activities. It is very important to establish coordinated rapid efforts for disease identification by physicians and veterinarians; and to provide better harmonization of diagnostic tools and integrated national surveillance system. Disease transmission risk needs to be assessed for adequate planning of preventive measures. At this stage, no animals were studied, however, in order to fulfill the One Health approach, we are planning to study horses in the near future.

Culex torrentium: A Potent Vector for the Transmission of West Nile Virus in Central Europe.

The continuous circulation of West Nile virus (WNV) in Central, South and East Europe and its recent detection in several dead birds and two horses in Germany highlights the need for information on WNV vector competence of mosquitoes from Central Europe. Therefore, three common Culex species (Culex pipiens biotype pipiens, Culex pipiens biotype molestus and Culex torrentium) from Germany were orally infected with WNV and kept at 18 °C, 21 °C, 24 °C or 27 °C for 14 or 21 days post infection (dpi). Thereafter viable WNV was present in the saliva in all tested taxa, but only at incubation temperatures of 24 °C or 27 °C and predominantly at the extended incubation period of 21 dpi. Highest transmission efficiency rates of 17 % (24 °C) and 24% (27 °C) were found for Cx. torrentium. Culex p. pipiens and Cx. p. molestus showed low transmission efficiencies with a maximum of only 3%. Consequently, temperatures above 21 °C support transmission of WNV, which matches the predominant distribution of human WNV cases around the Mediterranean Sea and in South-East Europe. Culex torrentium has been identified as a potent vector for WNV in Central and Northern Europe, which highlights the need for surveillance of mosquito-borne viruses north of the Alps.