Enhancement of Aedes albopictus collections by ovitrap and sticky adult trap

Abstract Background: In the last decades, Aedes albopictus has become an increasing public health threat in tropical as well as in more recently invaded temperate areas due to its capacity to transmit several human arboviruses, among which Dengue, Chikungunya and Zika. Enhancing the efficiency of currently used collection approaches, such as ovitraps and sticky traps, is desirable for optimal monitoring of the species abundance, for assessment of the risk of arbovirus transmission and for the optimisation of control activities. Findings: Two sets of 4 × 4 Latin-square experiments were carried out in Tirana (Albania) to test whether modifications in ovitrap shape and size and in oviposition substrate would increase collections of Ae. albopictus eggs and whether hay-infusion would increase adult catches by sticky trap. Generalized Linear Mixed Models with negative binomial error distribution were carried out to analyse the data. Cylindrical ovitraps lined with germination paper yielded significantly higher egg catches than those exploiting either the (commonly used) wooden paddles or floating polystyrene blocks as oviposition substrates. No difference was observed between cylindrical and conical shaped ovitraps. Ovitraps and sticky traps baited with hay infusion yielded significantly higher egg and adult catches than un-baited ones. A significant relationship between ovitrap and sticky trap catches was observed both in the absence and in the presence of attractants, with ovitrap catches increasing more than sticky trap catches at increasing adult female densities. Conclusions: This study provides grounds for optimisation of ovitraps and sticky traps as monitoring tools for Ae. albopictus by (i) supporting use of germination paper as most appropriate oviposition substrate; (ii) suggesting the possible use of stackable conical ovitraps for large scale monitoring; (iii) confirming the use of hay-infusion to increase egg catches in ovitraps, and showing that hay-infusion also significant increases adult catches by sticky traps

Forecasting the spatial and seasonal dynamic of Aedes albopictus oviposition activity in Albania and Balkan countries

The increasing spread of the Asian tiger mosquito, Aedes albopictus, in Europe and US raises public health concern due to the species competence to transmit several exotic human arboviruses, among which dengue, chikungunya and Zika, and urges the development of suitable modeling approach to forecast the spatial and temporal distribution of the mosquito. Here we developed a dynamical species distribution modeling approach forecasting Ae. albopictus eggs abundance at high spatial (0.01 degree WGS84) and temporal (weekly) resolution over 10 Balkan countries, using temperature times series of Modis data products and altitude as input predictors. The model was satisfactorily calibrated and validated over Albania based observed eggs abundance data weekly monitored during three years. For a given week of the year, eggs abundance was mainly predicted by the number of eggs and the mean temperature recorded in the preceding weeks. That is, results are in agreement with the biological cycle of the mosquito, reflecting the effect temperature on eggs spawning, maturation and hatching. The model, seeded by initial egg values derived from a second model, was then used to forecast the spatial and temporal distribution of eggs abundance over the selected Balkan countries, weekly in 2011, 2012 and 2013. The present study is a baseline to develop an easy-handling forecasting model able to provide information useful for promoting active surveillance and possibly prevention of Ae. albopictus colonization in presently non-infested areas in the Balkans as well as in other temperate regions

Genetic and microbial diversity of the invasive mosquito vector species <i>Culex tritaeniorhynchus</i> across its extensive inter-continental geographic range

AbstractCulex (Cx.) tritaeniorhynchus is a mosquito species with an extensive and expanding inter-continental geographic distribution, currently reported in over 50 countries, across Asia, Africa, the Middle East, Europe and now Australia. It is an important vector of medical and veterinary concern, capable of transmitting multiple arboviruses which cause significant morbidity and mortality in human and animal populations. In regions endemic for Japanese encephalitis virus (JEV) in Asia, Cx. tritaeniorhynchus is considered the major vector and this species has also been shown to contribute to the transmission of several other significant zoonotic arboviruses, including Rift Valley fever virus and West Nile virus.Significant variation in vectorial capacity can occur between different vector populations. Obtaining knowledge of a species from across its geographic range is crucial to understanding its significance for pathogen transmission across diverse environments and localities. Vectorial capacity can be influenced by factors including the mosquito genetic background, composition of the microbiota associated with the mosquito and the co-infection of human or animal pathogens. In addition to enhancing information on vector surveillance and potential risks for pathogen transmission, determining the genetic and microbial diversity of distinct populations of a vector species is also critical for the development and application of effective control strategies.In this study, multiple geographically dispersed populations of Cx. tritaeniorhynchus from countries within Europe, Africa, Eurasia and Asia were sampled. Molecular analysis demonstrated a high level of genetic and microbial diversity within and between populations, including genetic divergence in the mosquito CO1 gene, as well as diverse microbiomes identified by 16S rRNA gene amplicon sequencing. Evidence for the detection of the endosymbiotic bacteria Wolbachia in some populations was confirmed using Wolbachia-specific PCR detection and sequencing of Wolbachia MLST genes; in addition to PCR-based detection of insect-specific viruses. Laboratory vector competence showed Cx. tritaeniorhynchus from a Greek population are likely to be competent vectors of JEV. This study expands understanding of the diversity of Cx. tritaeniorhynchus across its inter-continental range, highlights the need for a greater focus on this invasive vector species and helps to inform potential future directions for development of vector control strategies.</jats:p

Altitudinal Variations In Wing Morphology Of Aedes Albopictus (Diptera, Culicidae) In Albania, The Region Where It Was First Recorded In Europe

The rapid spread and settlement of Aedes albopictus mosquitoes across at least 28 countries in Europe, as well as several countries in Asia Minor, the Middle East and Africa, has made it one of the most invasive species of all time. Even though the biology of Ae. albopictus in its native tropical environment has been documented for a long time, the biology and ecology of this species in newly colonized temperate environments remain poorly known despite its important role as a vector for about twenty arboviruses. In this context, the main goals of this work were to investigate Ae. albopictus phenotypic variations at a local scale in Albania, the country where Ae. albopictus was first recorded in Europe, and to determine if its phenotypes could be affected by altitude. Analysis of Ae. albopictus wing phenotypes was performed using a geometric morphometric approach. We observed shape and size variations among altitudinal populations of Ae. albopictus. Differences of wing phenotypes were highlighted between altitude groups for male and female mosquitoes. The phenotypic variations observed in Ae. albopictus between altitudinal groups indicated these populations are exposed to environmental and ecological pressures. These results suggest the presence of phenotypic plasticity in this species.PubMedWo

Detection of Leishmania infantum and a Novel Phlebovirus (Balkan Virus) from Sand Flies in Albania

WOS: 000390243200012PubMed ID: 27788062Objective: To organize entomological campaigns to trap sand flies in selected regions of Albania and to test them for the presence of existing or new phleboviruses and for leishmania DNA. Methods: Sand flies were collected in 14 locations from May to October 2014 using three different types of traps. Pools with a maximum of 30 individuals were prepared according to gender, trapping site, and trapping date; they were tested for the presence of (1) phlebovirus RNA with three different PCR systems (2) and Leishmania DNA using two different real-time PCR assays. Results: A total of 972 sand flies (568 females, 404 males) were aliquoted to 55 pools. Three pools (in two different regions) were positive for Leishmania infantum. Two pools (Kruje region) were positive for phlebovirus RNA and a 575-nucleotide (nt) colinearized sequence of a novel virus most closely related to but clearly distinct from Tehran virus (16% and 3% divergence at nt and amino acid levels). Next generation sequencing analysis indicated that this virus might be transmitted by either Phlebotomus neglectus, Phlebotomus tobbi, or both vectors. Conclusions: Visceral leishmaniasis has been clinically recognized in Albania for at least 80 years; however, this is the first time that L. infantum, detected by molecular means, has been reported in sand flies in Albania. At the outset of this study, only Adria virus (Salehabad species) was recognized in Albania. A novel virus, Balkan virus, was identified and genetic analysis revealed that it belongs to the Sandfly fever Naples virus group containing human pathogens.EUEuropean Union (EU) [FP7-261504 EDENext]; European UnionEuropean Union (EU) [653316]; Fondation Infectiopole Sud, Marseille, FranceThis work was supported through funds received from (1) the EU grant FP7-261504 EDENext and this article is catalogued by the EDENext Steering Committee as EDENext449 (www.edenext.eu), (2) the European Virus Archive goes Global (EVAg) project in the European Union's Horizon 2020 research and innovation program under grant agreement No 653316 (http://global.european-virus-archive.com). N. A. was supported by a PhD funding from Fondation Infectiopole Sud, Marseille, France. The work of R.N. Charrel was carried out under the framework of the EurNegVec (TD1303) COST Action

The current status of phlebotomine sand flies in Albania and incrimination of Phlebotomus neglectus (Diptera, Psychodidae) as the main vector of Leishmania infantum.

The incidence of visceral leishmaniasis (VL) in Albania is higher than in other countries of southern Europe, however the role of local sand fly species in the transmission of Leishmania infantum was not addressed conclusively. In 2006, a country-wide collection of sand flies performed in 14 sites selected based on recent occurrence of VL cases showed that Phlebotomus neglectus was by far the most prevalent species (95.6%). Furthermore, 15% of pools made from 422 P. neglectus females tested positive for Leishmania sp. genomic DNA. In the same year, Culicoides trapping was performed for bluetongue disease surveillance in 91 sites of southern Albania, targeting livestock farms regardless recent occurrence of VL in the surveyed areas. In 35 sites where sand flies were collected along with midges, Phlebotomus perfiliewi was the most prevalent among the Phlebotomus species identified, however search for leishmanial DNA in females of this species was unsuccessful. In 2011, sand flies were trapped in 4 sites of north Albania characterized by high VL incidence, and females were dissected to search for Leishmania infections. Both P. neglectus and P. tobbi were collected at high densities. Two positive specimens were detected from a sample of 64 P. neglectus trapped in one site (3.1%). Parasites were successfully cultured from one specimen and characterized as belonging to Leishmania infantum zymodeme MON-1, the only zymodeme so far identified as the agent of human and canine leishmaniasis in the country. Altogether our studies indicate that P. neglectus is the main leishmaniasis vector in Albania

Prevalence and sand fly species identified by county and district in the 2006 country-wide study targeting VL endemic sites (Study 1).

<p>Prevalence and sand fly species identified by county and district in the 2006 country-wide study targeting VL endemic sites (Study 1).</p

<i>Leishmania</i> infections detected in wild-caught sand flies in sites of Lezhë district, September 2011 (Study 3).

<p><i>Leishmania</i> infections detected in wild-caught sand flies in sites of Lezhë district, September 2011 (Study 3).</p

Albanian <i>Leishmania</i> isolates identified from 1988 through 2012 by MultiLocus Enzyme Electrophoresis (MLEE) or PCR-restriction fragments length polymorphism of ribosomal internal transcribed spacer-1 (ITS-1 PCR-RFLP).

<p>Albanian <i>Leishmania</i> isolates identified from 1988 through 2012 by MultiLocus Enzyme Electrophoresis (MLEE) or PCR-restriction fragments length polymorphism of ribosomal internal transcribed spacer-1 (ITS-1 PCR-RFLP).</p

Molecular detection and characterization of <i>Leishmania</i> from wild-caught sand flies in Albania.

<p><b>(A)</b> Nested-PCR targeting a <i>Leishmania</i> sp. small-subunit ribosomal DNA sequence. Lane C₁-: uninfected reared sand fly DNA; lane C₂-: PCR Master Mix with no DNA; lanes 2, 4, 5, 7, 8, 10, 11: positive <i>P</i>. <i>neglectus</i> pools; lane 13: positive <i>P</i>. <i>tobbi</i> pool; lanes 1, 3, 6, 9, 12, 14: negative <i>P</i>. <i>perfiliewi</i> pools; lane C₁+: <i>L</i>. <i>infantum</i> promastigotes DNA; C₂+: <i>L</i>. <i>infantum</i> promastigotes DNA mixed with uninfected reared sand fly DNA; lane M: 100 base pair ladder (Promega). <b>(B)</b> ITS-1 n-PCR-RFLP for <i>Leishmania</i> species characterization. Lane M: 100 base pair ladder (Promega); lane 1: <i>Leishmania</i> isolate from Albanian <i>P</i>. <i>neglectus</i> (IMJN/AL/2011/MJN2-ISS3056); lane 2: <i>L</i>. <i>infantum</i> (human isolate from Albania, MHOM/AL/2006/ISS2840); lane 3: <i>L</i>. <i>infantum</i> (dog isolate from Albania, MCAN/AL/2006/ISS2841); lane 4: WHO reference strain for <i>L</i>. <i>infantum</i> (MHOM/TN/1980/IPT-1).</p