Nurdan Ozer

Genetic and phenotypic variation of the malaria vector Anopheles atroparvus in southern Europe.

BackgroundThere is a growing concern that global climate change will affect the potential for pathogen transmission by insect species that are vectors of human diseases. One of these species is the former European malaria vector, Anopheles atroparvus. Levels of population differentiation of An. atroparvus from southern Europe were characterized as a first attempt to elucidate patterns of population structure of this former malaria vector. Results are discussed in light of a hypothetical situation of re-establishment of malaria transmission.MethodsGenetic and phenotypic variation was analysed in nine mosquito samples collected from five European countries, using eight microsatellite loci and geometric morphometrics on 21 wing landmarks.ResultsLevels of genetic diversity were comparable to those reported for tropical malaria vectors. Low levels of genetic (0.004 <FST<0.086) and phenotypic differentiation were detected among An. atroparvus populations spanning over 3,000 km distance. Genetic differentiation (0.202 <FST<0.299) was higher between the sibling species An. atroparvus and Anopheles maculipennis s.s. Differentiation between sibling species was not so evident at the phenotype level.ConclusionsLevels of population differentiation within An. atroparvus were low and not correlated with geographic distance or with putative physical barriers to gene flow (Alps and Pyrenées). While these results may suggest considerable levels of gene flow, other explanations such as the effect of historical population perturbations can also be hypothesized.

New molecular data shed light on the global phylogeny and species limits of the Rhipicephalus sanguineus complex.

The Rhipicephalus sanguineus complex is a group of closely related tick species distributed all around the world. In this study, using mitochondrial 16S ribosomal DNA, new specimens of R sanguineus sensu lato from Turkey and Rhipicephalus camicasi from Kenya, were evaluated together with available sequences of this complex in GenBank. Our objectives were to delimit the complex, re-evaluate its global phylogeny and develop a reconstruction of its biogeographic history. Given Turkeys geographical location and its neighboring status within Africa, Asia and Europe, molecular information of R. sanguineus s.l. species from this region could have important implications both on a regional and global scale. Phylogenetic trees obtained with three methods (Bayesian, Maximum Likelihood and Maximum Parsimony) were highly similar and consensus trees gave the same branching patterns and similar node support values. A total of four different clades with up to 9 Operational Taxonomic Units formed strong monophyletic groups. Biogeographic reconstructions demonstrated the importance of populations in Middle East (Turkey) in the spread of the group from Europe to Africa and Asia. Data supported previous conclusions on the existence of two species of R. sanguineus s.l. in South America and the strong molecular similarity between R. camicasi and the so-called tropical lineage of R. sanguineus s.l. These results point to the need of a re-evaluation of most specimens designated as R. sanguineus s.l. in East Europe, Middle East, Africa and Asia after an adequate re-description of this taxon.

Species distribution and detection of Crimean Congo Hemorrhagic Fever Virus (CCHFV) in field-collected ticks in Ankara Province, Central Anatolia, Turkey

Ticks may act as vectors for a number of infectious diseases including Crimean Congo Hemorrhagic Fever (CCHF). The causative agent is Crimean Congo Hemorrhagic Fever Virus (CCHFV), a member of Bunyaviridae, causing extensive ecchymosis, visceral bleeding and hepatic dysfunction with a high fatality rate in the affected individuals. CCHF was initially recognized in Turkey in 2002 and the current number of reported cases exceeds 4,400. This study was conducted to confirm the presence of tick species established as potential CCHFV vectors and investigate CCHFV activity in ticks at Ankara province, Turkey’s second most-densely populated province, where CCHF cases were demonstrated. A total of 1,196 adult ticks, collected from various animals and vegetation in 12 sites located in 5 counties of Ankara during April–July 2010 were identified to species level. Twenty-two tick pools from county K2 were also evaluated for the presence of CCHFV RNA via a one-step real-time RT-PCR assay and reactive results were further confirmed by an in house nested RT-PCR assay. Nine tick species were identified: Rhipicephalus bursa (44.9%), R. sanguineus (18.9%), R. turanicus (18.1%), Haemaphysalis parva (8.3%), Hyalomma marginatum marginatum (5.4%), H. aegyptium (1.4%), H. anatolicum excavatum (1.3%), Hae. punctata (0.3%) and Dermacentor marginatus (0.2%). A total of five tick pools (22.7%) were reactive in real-time and nested RT-PCR assays. The pools included R. bursa, H. m. marginatum and Hae. parva ticks, collected from mammal hosts from two villages in one county. This is the first documentation of CCHFV activity in ticks from Ankara province, which indicates requirement for detailed surveillance to predict high risk zones in the region.

Food preference of Sancassania polyphyllae (Acari: Acaridae): living entomopathogenic nematodes or insect tissues?

Abstract Sancassania polyphyllae (Acari: Acaridae) adult female mites will feed on insect cadavers and infective juveniles (IJs) of entomopathogenic nematodes. Our objective was to determine whether S. polyphyllae has a food preference when offered a choice between tissues of Polyphylla fullo (Coleoptera: Scarabaeidae) or Galleria mellonella (Lepidoptera: Pyralidae), or IJs of Steinernema feltiae (Rhabditida: Steinernematidae) or IJs of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae). When offered a choice between no food and one of the different food sources, P. fullo, G. mellonella or S. feltiae IJs, S. polyphyllae had a significant preference for food sources compared to no food. When it was offered either no food or H. bacteriophora, there was no significant difference in the mite distribution. When offered two different food choices, P. fullo or G. mellonella, P. fullo or S. feltiae, and P. fullo or H. bacteriophora, the mite showed significant preferences for P. fullo larvae. In S. feltiae vs. G. mellonella and S. feltiae vs. H. bacteriophora experiments, S. polyphyllae showed significant a preference for S. feltiae. In three-choice experiments, S. polyphyllae had a preference for P. fullo, followed by S. feltiae, G. mellonella and H. bacteriophora, respectively. Our data confirm, in part, our hypothesis that when offered different food choices, this mite species prefers tissues of its phoretic host, P. fullo over lepidopteran host tissues or living IJs. Based on these laboratory data, H. bacteriophora should be used as a biological control agent against P. fullo over a Steinernema species.

West Nile virus studies in the Sanliurfa Province of Turkey

ABSTRACT We attempted to isolate West Nile virus from mosquitoes collected in the field for the first time in Turkey. A total of 6, 457 mosquito specimens from Culex pipiens Linnaeus, Ochlerotatus caspius (Pallas) and Aedes spp. species were included in this study. Culex pipiens samples made up 56% of the total species, O. caspius 24% and Aedes spp 20%. There were no positive results after studying mosquito samples using Real-time PCR, VecTest, and Vero cell culture. In serological tests of 181 human serum samples, 29 (16%) were found to be West Nile positive. On the basis of these results, we intend to collect more mosquito samples especially from those areas from which positive serum samples were obtained.

Generic amplification and next generation sequencing reveal Crimean-Congo hemorrhagic fever virus AP92-like strain and distinct tick phleboviruses in Anatolia, Turkey

BackgroundTicks are involved with the transmission of several viruses with significant health impact. As incidences of tick-borne viral infections are rising, several novel and divergent tick- associated viruses have recently been documented to exist and circulate worldwide. This study was performed as a cross-sectional screening for all major tick-borne viruses in several regions in Turkey. Next generation sequencing (NGS) was employed for virus genome characterization. Ticks were collected at 43 locations in 14 provinces across the Aegean, Thrace, Mediterranean, Black Sea, central, southern and eastern regions of Anatolia during 2014–2016. Following morphological identification, ticks were pooled and analysed via generic nucleic acid amplification of the viruses belonging to the genera Flavivirus, Nairovirus and Phlebovirus of the families Flaviviridae and Bunyaviridae, followed by sequencing and NGS in selected specimens.ResultsA total of 814 specimens, comprising 13 tick species, were collected and evaluated in 187 pools. Nairovirus and phlebovirus assays were positive in 6 (3.2%) and 48 (25.6%) pools. All nairovirus sequences were closely-related to the Crimean-Congo hemorrhagic fever virus (CCHFV) strain AP92 and formed a phylogenetically distinct cluster among related strains. Major portions of the CCHFV genomic segments were obtained via NGS. Phlebovirus sequencing revealed several tick-associated virus clades, including previously-characterized Antigone, Lesvos, KarMa and Bole tick viruses, as well as a novel clade. A wider host range for tick-associated virus strains has been observed. NGS provided near-complete sequences of the L genomic segments of Antigone and KarMa clades, as well as Antigone partial S segment. Co- infections of CCHFV and KarMa or novel phlebovirus clades were detected in 2.1% of the specimens.ConclusionsWidespread circulation of various tick-associated phlebovirus clades were documented for the first time in Anatolia. Genomes of CCHFV AP92 strains were identified in previously unexplored locations. NGS provided the most detailed genomic characterization of the Antigone and KarMa viruses to date. The epidemiological and health-related consequences must be elucidated.

Bionomics of the entomopathogenic nematode, Steinernema weiseri (Rhabditida: Steinernematidae)

This study describes some important bio-ecological properties of Steinernema weiseri, a recently isolated entomopathogenic nematode species in Turkey. The effects of temperature on the infectivity and development of S. weiseri were determined at 5, 8, 10, 15, 20, 25 and 30°C. The greatest and the fastest mortality of Galleria mellonella larvae was observed at 20 and 25°C (ca 2 days) and the slowest at 5°C in 11.5 days. The emergence time of the new generation of infective juveniles (IJ) from the host cadaver was shortest at 20 and 25°C (ca 9 days) and the longest at 8°C (ca 40 days). No progeny were observed at 5 and 30°C. At the tested temperatures, the lowest number of new generation IJ was obtained at 8 and 10°C and the highest at 15 and 20°C. The life cycle, determined at 23-24°C under laboratory conditions using G. mellonella as a host, took 9 days to complete. Our study suggests that the Turkish isolate of S. weiseri is adapted to cold temperatures. Steinernema weiseri has a wide host range and infects and develops well in larvae of Agrotis sp., Ceratitis capitata, Cydia splendana, Synanthedon vespiformis and Hoplocampa flava, but it infects and develops poorly in Polyphylla fullo. Larval stages of C. cossus were divided into four groups based on the diameter of their head capsules. Steinernema weiseri developed well in larval stages in Group 1 (the smallest head capsule) and Group 2 of Cossus cossus but, interestingly, very low infection and nematode development occurred in the Group 3 and Group 4 larval stage of C. cossus. No nematode infection was observed in Gryllotalpa gryllotalpa either.