West Nile virus (WNV) is a flavivirus transmitted by mosquitoes. Birds are the reservoir for the virus; humans, horses and other mammals are dead-end hosts. Infections caused by WNV in humans can vary from asymptomatic infections to West Nile fever (WNF) or West Nile neuroinvasive disease (WNND). In 1995, a serosurvey was performed in Slovenia on forest workers, and WNV specific IgG antibodies were confirmed in 6.8% of the screened samples, indicating that WNV is circulating in Slovenia. No human disease cases were detected in Slovenia until 2013, when the first case of WNV infection was confirmed in a retrospective study in a 79-year old man with meningitis. In 2018, three patients with WNND were confirmed by laboratory tests, with detection of IgM antibodies in the cerebrospinal fluid of the patients. In one of the patients, WNV RNA was detected in the urine sample. In 2017, 2018 and 2019, a mosquito study was performed in Slovenia. Mosquitoes were sampled on 14 control locations and 35 additional locations in 2019. No WNV was detected in mosquitoes in 2017 and 2019, but we confirmed the virus in a pool of Culex sp. mosquitoes in 2018. The virus was successfully isolated, and complete genome sequence was acquired. The whole genome of the WNV was also sequenced from the patient's urine sample. The whole genome sequences of the WNV virus detected in Slovenian patient and mosquito indicate the virus most likely spread from the north, because of the geographic proximity andbecause the sequences cluster with the Austrian and Hungarian sequences. A sentinel study was performed on dog sera samples, and we were able to confirm IgG antibodies in 1.8% and 4.3% of the samples in 2017 and 2018, respectively. Though Slovenia is not a highly endemic country for WNV, we have established that the virus circulates in Slovenia.
COBISS.SI-ID: 22975235
Autochthonous transmissions of mosquito-borne diseases were described in close proximity to Slovenia where the knowledge of mosquito species and the viruses they transmit remains very scarce. Therefore we aimed to assess the burden mosquitoes bring to the local community and to test mosquitoes for the presence of the selected zoonotic arboviruses, i. e. Dengue (DENV), West Nile (WNV) and Chikungunya (CHIKV). A pilot mosquito monitoring was conducted in 2012 within two municipalities based on adult mosquito trapping. Altogether 2007 adult mosquitoes were caught. Females of Aedes albopictus and Culex pipiens represented the majority of the total mosquito catch. In sites with more households and nearby greenery, catches of Ae. albopictus were more abundant. Highest numbers of Cx. pipiens females were caught close to a nature reserve, where many bird species stop during their migrations. Trapping results are consistent with both species’ feeding behaviour. Female mosquitoes were grouped into 58 pools according to species, location and date of catch. Real time RT-PCRs for WNV, DENV and CHIKV were performed, but no arboviral genomes were detected in any of the tested mosquito pools. However, amplicons were obtained in three pools when using generic RT-PCR markers for flaviviruses. The viruses detected were propagated and isolated in mosquito cell line C3/36 and identified with sequencing as mosquito-only flaviviruses (MOFs). The important contributions of this study are a successful first isolation of MOFs and confirmation of the presence of the invasive mosquito Ae. albopictus in Slovenia.
COBISS.SI-ID: 1540808132
In Slovenia, two invasive mosquito species are present, Aedes albopictus (Skuse, 1895) (Diptera: Culicidae) and Aedes japonicus (Theobald, 1901) (Diptera: Culicidae). In this study, we examined their actual distribution and suitable habitats for new colonizations. Data from survey of species presence in 2013 and 2015, bioclimatic variables and altitude were used for the construction of predictive maps. We produced various models in Maxent software and tested two bioclimatic variable sets, WorldClim and CHELSA. For the variable selection of Ae. albopictus modelling we used statistical and expert knowledge-based approach, whereas for Ae. j. japonicus we used only a statistically based approach. The best performing models for both species were chosen according to AIC scorebased evaluation. In 2 yr of sampling, Ae. albopictus was largely confined to the western half of Slovenia, whereas Ae. j. japonicus spread significantly and can be considered as an established species in a large part of the country. Comparison of models with WorldClim and CHELSA variables for both species showed models with CHELSA variables as a better tool for prediction. Finally, we validated the models performance in predicting distribution of species according to collected field data. Our study confirms that both species are co-occurring and are sympatric in a large part of the country area. The tested models could be used for future prevention of invasive mosquitoes spreading in other countries with similar bioclimatic conditions.
COBISS.SI-ID: 1539710404
Viral and parasitic diseases transmitted by mosquitos and sand flies have always existed in Europe, but their spread and incidence became known only with larger outbreaks, when appropriate laboratory diagnostic and identification methods were developed. In order to identify the prevalence of pathogens, as well as their vectors, many countries have begun to develop surveillance systems. In 2017, we began to monitor vectors of emerging microorganisms in Slovenia. In 2017 and 2018, mosquitoes and phlebotomine sand flies were sampled at different locations in Slovenia. In 2017, the pilot year, we sampled 199 mosquitoes and 10 phlebotomine sand flies. Favourable environmental conditions and an expanded sampling area enabled us to sample 3054 mosquitoes and 506 sand flies in 2018. Vectors were grouped into pools of up to 20 animals and analysed for the presence of pathogens with molecular methods and attempts to isolate the virus. In 2018, we demonstrated the presence of the West Nile virus and the Usutu virus for the first time in mosquitoes in Slovenia. We also managed to isolate the Usutu virus from a pool of mosquitoes. We confirmed several bunyaviruses in mosquito groups, namely, 15 pools of mosquitoes carried orthobunyaviruses and 11 groups of mosquitoes were infected with phleboviruses. In one group of sand flies we confirmed a phlebovirus. To accurately define the risk posed by microorganisms transmitted by vectors, we will continue the study next year, thus ensuring a sufficient number of examined samples and increasing the reliability of both vector and pathogen surveillance in Slovenia.
COBISS.SI-ID: 34064345
The first record of Aedes koreicus was made in a village Lovrenc na Dravskem polju, south-eastern part of country. The discovery of Ae. koreicus in various continental European countries motivated us to revise samples of the collected Ae. japonicus japonicus. We found Ae. koreicus in samples from 2013 where the larvae were misidentified as Ae. j. japonicus. The species was identified morphologically and molecularly. The first discovery of Ae. koreicus advocates an urgent need for a nation-wide mosquito surveillance programme.
COBISS.SI-ID: 18057305