Detection of West Nile virus and tick-borne encephalitis virus in birds in Slovakia, using a universal primer set.

West Nile virus (WNV) is a mosquito-borne neurotropic pathogen that presents a major public health concern. Information on WNV prevalence and circulation in Slovakia is insufficient. Oral and cloacal swabs and bird brain samples were tested for flavivirus RNA by RT-PCR using newly designed generic primers. The species designation was confirmed by sequencing. WNV was detected in swab and brain samples, whereas one brain sample was positive for tick-borne encephalitis virus (TBEV). The WNV sequences clustered with lineages 1 and 2. These results confirm the circulation of WNV in birds in Slovakia and emphasize the risk of infection of humans and horses.

Potential mosquito (Diptera:Culicidae) vector of Dirofilaria repens and Dirofilaria immitis in urban areas of Eastern Slovakia.

This paper follows the study from 2013 focused on the molecular screening of mosquitoes as vectors of Dirofilaria spp. which provided the information on Aedes vexans as a potential vector of Dirofilaria repens in Slovakia. Current entomological and molecular research indicates that Ae. vexans can participate also in the transmission of Dirofilaria immitis within the region. Using the standard PCR method, we examined 10,500 mosquitoes (Ae. vexans, Ae. rossicus, Anopheles maculipennis s.l., Ochlerotatus sticticus, Ochlerotatus cantans, Ochlerotatus caspius, Culex pipiens/Culex torrentium, Coquillettidia richiardii), collected using CO2-baited traps at six locations in the Eastern Slovakia. Out of 105 pools, 6 pools of mosquitoes Ae. vexans were positive for D. repens DNA (minimum infective rate in Ae. vexas was 6:6.900, i.e. 0.8 per 1.000 mosquitoes), within which 4 were concurrently positive for D. immitis (minimum infective rate in Ae. vexans was 4:6.900 i.e. 0.5 per 1.000 mosquitoes).

Zoonotic Dirofilaria repens (Nematoda: Filarioidea) in Aedes vexans mosquitoes, Czech Republic.

The surveillance of vectors for arthropod-borne pathogens is nowadays an important tool in surveillance programmes throughout Europe. Whereas many studies have been performed to screen arthropods for viruses or bacterial pathogens, only limited information is available concerning the geographical distribution and vector range of pathogenic filariae in Central Europe. To consider the prevalence of filarial parasites in mosquito vectors, we performed a molecular survey of mosquitoes for filarial DNA. Mosquito collection was conducted at six study sites in the South Moravian region (Czech Republic) close to the borders with Slovakia and Austria from 2009 to 2011. Molecular screening of mosquitoes was conducted using conventional PCR with primers designed to amplify the mitochondrial cytochromoxidase subunit I gene as well as the partial 5.8S ribosomal RNA gene. A total of 13,222 mosquitoes belonging to six species were captured and distributed into 237 pools with different numbers of individuals. Overall, four pools were positive for Dirofilaria repens (a minimum infection rate 0.03%) at two study sites (both natural and urban). Another filarial parasite detected during a study into Aedes vexans mosquitoes revealed the closest homology to Setaria spp. We detected specific D. repens DNA in Ae. vexans mosquitoes for the first time in the Czech Republic and confirmed the circulation of Dirofilaria spp. in a natural focus of infection providing an epidemiological link between autochthonous canine cases and mosquito vectors in the area studied.

First record of Aedes albopictus in Slovakia.

During a routine inspection of the mosquito fauna in the Kosická Basin (Eastern Slovakia), in one of the monitored locations we have caught 4 females of the invasive mosquito Aedes albopictus, using the CO2 baited CDC traps. Occurrence of this particular mosquito has already been reported in many European countries; in Slovakia, however, this is the first finding ever. The finding of Ae. albopictus extends the list of the mosquito fauna in Slovakia to 50 species and Slovakia thus ranks among other 20 European countries where this mosquito was observed. The presence of Ae. albopictus increased the probability of transmission of canine and human dirofilariosis in urban environment.

Dirofilaria repens microfilariae in Aedes vexans mosquitoes in Slovakia.

In this study, we screened field-caught mosquitoes for presence of Dirofilaria spp. by using a polymerase chain reaction (PCR) assay. Potential occurrence of Dirofilaria repens and Dirofilaria immitis microfilariae was examined in 3,600 mosquitoes of eight species (Aedes vexans, Aedes cinereus, Aedes rossicus, Culex pipiens, Culiseta annulata, Ochlerotatus sticticus, Ochlerotatus cantans and Ochlerotatus caspius) collected from five locations in two districts (Kosice and Trebisov) of Eastern Slovakia, endemic region of canine dirofilariasis. Collection of mosquitoes was performed between May and August 2012 in premises known to be inhabited by Dirofilaria-infected dogs. PCR assays were performed on 72 pools, each pool containing 50 mosquitoes of the same species, collected on the same location. Each pool was examined separately for the presence of D. immitis and D. repens, respectively. A positive finding of D. repens was recorded in one pool of A. vexans mosquitoes collected in Kosické Olsany village. Minimum infection rate in A. vexans was 1:1,750, i.e. 0.57 per 1,000 mosquitoes. The identity of D. repens was confirmed by direct sequencing of PCR product which has shown 100% homology with sequence attributed to D. repens (GenBank accession number AJ271614). This study represents the first molecular evidence of D. repens microfilariae in mosquitoes in Slovakia and highlights a need for better surveillance of zoonotic dirofilariasis in central Europe.