BUSCADOR RECOLECTA

Mosquitoes are the deadliest animals in the world. Their ability to carry and spread diseases to humans causes millions of deaths every year. Due to the lack of efficient vaccines, the control of mosquito-borne diseases primarily relies on the management of the vector. Traditional control methods are insufficient to control mosquito populations. The sterile insect technique (SIT) is an additional control method that can be combined with other control tactics to suppress specific mosquito populations. The SIT requires the mass-rearing and release of sterile males with the aim to induce sterility in the wild female population. Samples collected from the environment for laboratory colonization, as well as the released males, should be free from mosquito-borne viruses (MBV). Therefore, efficient detection methods with defined detection limits for MBV are required. Although a one-step reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) method was developed to detect arboviruses in human and mosquito samples, its detection limit in mosquito samples has yet to be defined. We evaluated the detection sensitivity of one step RT-qPCR for targeted arboviruses in large mosquito pools, using pools of non-infected mosquitoes of various sizes (165, 320 and 1600 mosquitoes) containing one infected mosquito body with defined virus titers of chikungunya virus (CHIKV), usutu virus (USUV), West Nile virus (WNV) and Zika virus (ZIKV). CHIK, USUV, ZIKV, and WNV virus were detected in all tested pools using the RT-qPCR assay. Moreover, in the largest mosquito pools (1600 mosquitoes), RT-qPCR was able to detect the targeted viruses using different total RNA quantities (10, 1 and 0.1 ng per reaction) as a template. Correlating the virus titer with the total RNA quantity allowed the prediction of the maximum number of mosquitoes per pool in which the RT-qPCR can theoretically detect the virus infection. Mosquito-borne viruses can be reliably detected by RT-qPCR assay in pools of mosquitoes exceeding 1000 specimens. This will represent an important step to expand pathogen-free colonies for mass-rearing sterile males for programmes that have a SIT component by reducing the time and the manpower needed to conduct this quality control process.

A 2-year longitudinal study of enzyme-linked immunosorbent assay (ELISA) antibodies against Phlebotomus perniciosus and Phlebotomus papatasi (Diptera: Psychodidae) sandfly saliva was performed in 32 Beagle dogs treated preventively with an imidacloprid-permethrin topical insecticide in an endemic area in Spain. Dogs were grouped into three sandfly exposure groups according to the time of inclusion in the study. Assays analysed immunoglobulin G (IgG) against salivary gland homogenates (SGH) of both species and recombinant P. papatasi rSP32 and P. perniciosus rSP03B proteins in serum. The dogs were participating in a Leishmania infantum (Kinetoplastida: Trypanosomatidae) vaccine trial and were experimentally infected with the parasite in the second year. No dog acquired natural L. infantum infections during the first year, but most developed anti-saliva antibodies, and median log-transformed optical densities (LODs) were seasonal, mimicking those of local sandflies. This indicates that the repellent efficacy of the insecticide used is below 100%. Multi-level modelling of LODs revealed variability among dogs, autocorrelation and differences according to the salivary antigen and the dog's age. However, dog seroprevalence, estimated using pre-exposure LODs as cut-offs, was relatively low. This, and the fact that dogs did not become naturally infected with L. infantum, would support the efficacy and usefulness of this imidacloprid-permethrin topical insecticide in canine leishmaniasis control., The project was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) (grants Pr. Ref. AGL2013-46981-R, RTC-2016-50005-1, SAF2016-81003-R and SAF2016-80998-R), the Instituto de Salud Carlos III within the Network of Tropical Diseases Research RICET (RD16/0027/0016 and RD16/0027/0005) and (FEDER). The authors of this paper are members of and receive support from COST Action TD1303 (European Network for Neglected Vectors and Vector-Borne Infections), INFRAVEC 2 (Research Infrastructures for the Control of Vector-Borne Diseases, H2020, no. 731060) and VectorNet, a European network for sharing data on the geographic distribution of arthropod vectors transmitting human and animal disease agents (contract OC/EFSA/AHAW/2013/02-FWC1) funded by the European Food Safety Authority (EFSA) and the European Centre for Disease Prevention and Control (ECDC). TS and PV were supported by Ministry of Education, Youth and Sport of the Czech Republic (MSMT) (project OPVVV 16-019/0000759) and Charles University (Research Centre UNCE 204072)., Peer reviewed

Aedes albopictus mosquitoes have been experimentally demonstrated to be a competent vector for Zika virus (ZIKV) in different countries, but there are still some gaps related to the importance of Ae. albopictus in ZIKV transmission. Recent studies on Spanish Ae. albopictus populations showed controversial results for ZIKV transmission and no studies have been performed yet to detect infectious ZIKV in saliva of progeny of infected female mosquitoes. Herein, the horizontal transmission (HT) and vertical transmission (VT) of ZIKV in field-collected Ae. albopictus mosquitoes from Spain were evaluated for ZIKV strains (African I and Asian lineages) to better estimate the risk of ZIKV transmission by Ae. albopictus. The two field-collected Ae. albopictus populations assayed were infected by all tested ZIKV strains, however differences in terms of vector competence were detected depending on strain-population combination. Moreover, a higher susceptibility to the African I lineage strain than to the Asian lineage strain was observed in both mosquito populations. On the other hand, VT was demonstrated for both ZIKV lineages, detecting the virus in both males and females of the progeny of infected females, although importantly ZIKV dissemination and transmission were not detected in the infected females from the offspring. The results of the present study demonstrate that Spanish Ae. albopictus populations could sustain virus transmission in case of ZIKV introduction, but VT would play a poor role in the ZIKV epidemiology. Overall, our results provide helpful information to health authorities to establish efficient surveillance and vector control programmes for ZIKV., This work was supported by H2020 Research Infrastructures [grant number Infravec2, no. 731060]; Horizon 2020 Framework Programme [grant number ZIKAlliance, no. 734548]; Agència de Gestió d'Ajuts Universitaris i de Recerca.

[Description of methods used for collection/generation of data] We collected birds infected by Plasmodium cathemerium and Plasmodium relictum and uninfected birds. We collected mosquito larvae that were raised in the lab. Adult mosquitoes were divided in 3 groups allowed them to feed overnight on a P. relictum-infected bird, a P. cathemerium-infected bird and an uninfected control bird. For transcriptome analyses, we processed mosquitoes at three time points after exposure, 24 hours post-infection (hpi), 10 days post-infection (dpi) and 21 dpi. At each time point, we created pools of 5 mosquitoes of each infection status capturing the mosquitoes alive and immediately transferring them to dry ice. We preserved the mosquitoes at -80ºC until RNA extractions were carried out. We collected a total of 36 samples including controls (4 pools x 3 time points x 3 conditions). We extracted RNA and DNA from pools of 5 mosquitoes using TRIzol® (Invitrogen, Carlsbad, CA, USA) followed by column purification using RNeasy mini kit® (QIAGEN, Hilden, Germany). RNA samples were submitted to the Polo d’Innovazione di Genomica, Genetica e Biologia, Siena (Italy) where library preparation and sequencing were carried out., [Methods for processing the data] Illumina sequencing and RNAseq pipeline available with the published paper., Metadata describing the experimental conditions of an RNA seq experiment that aims to analyse the differential gene expression of Culex pipiens when exposed to either Plasmodium relictum or Plasmodium cathemerium. The data includes the information of the corresponding project published at the European Nucleotide Archive (https://www.ebi.ac.uk/ena/browser/view/PRJEB41609), sample IDs and the links to the generated fasta files., This publication was supported by the project Research Infrastructures for the control of vector-borne diseases (Infravec2), which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 731060., Peer reviewed