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Lilja T, Lindström A, Hernández-Triana LM, Di Luca M, Lwande OW. European Culex pipiens Populations Carry Different Strains of Wolbachia pipientis. INSECTS 2024; 15:639. [PMID: 39336607 PMCID: PMC11432034 DOI: 10.3390/insects15090639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 08/20/2024] [Accepted: 08/22/2024] [Indexed: 09/30/2024]
Abstract
The mosquito Culex pipiens occurs in two ecotypes differing in their mating and overwintering behavior: pipiens mate in open environments and diapause, and molestus also mate in small spaces and is active throughout the year. Cx. pipiens carry Wolbachia endosymbionts of the wPip strain, but the frequency of infection differs between studied populations. Wolbachia infection affects the host reproductive success through cytoplasmic incompatibility. wPip Wolbachia is divided into five types, wPip I-V. The type of wPip carried varies among Cx. pipiens populations. In northern European locations different wPip types are found in the two ecotypes, whereas in southern locations, they often carry the same type, indicating differences in hybridization between ecotypes. In this study, Cx. pipiens specimens of both ecotypes were collected from Sweden and compared to specimens from Norway, England, Italy, and the Netherlands, as well as Cx. quinquefasciatus from Mali and Thailand. The abundance varied, but all specimens were infected by Wolbachia, while the tested specimens of other mosquito species were often uninfected. The wPip strains were determined through the sequence analysis of Wolbachia genes ank2 and pk1, showing that Cx. pipiens ecotypes in Scandinavia carry different wPip strains. The observed differences in wPip strains indicate that hybridization is not frequent and may contribute to barriers against hybridization of the ecotypes in Sweden and Norway.
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Affiliation(s)
- Tobias Lilja
- Department of Microbiology, Swedish Veterinary Agency, 751 89 Uppsala, Sweden
| | - Anders Lindström
- Department of Microbiology, Swedish Veterinary Agency, 751 89 Uppsala, Sweden
| | - Luis M Hernández-Triana
- Vector-Borne Diseases Research Group, Virology Department, Animal and Plant Health Agency (APHA), Addlestone KT15 3NB, UK
| | - Marco Di Luca
- Department of Infectious Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
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2
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Blom R, Krol L, Langezaal M, Schrama M, Trimbos KB, Wassenaar D, Koenraadt CJM. Blood-feeding patterns of Culex pipiens biotype pipiens and pipiens/molestus hybrids in relation to avian community composition in urban habitats. Parasit Vectors 2024; 17:95. [PMID: 38424573 PMCID: PMC10902945 DOI: 10.1186/s13071-024-06186-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 02/07/2024] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Culex pipiens sensu stricto (s.s.) is considered the primary vector of Usutu virus and West Nile virus, and consists of two morphologically identical but behaviourally distinct biotypes (Cx. pipiens biotype pipiens and Cx. pipiens biotype molestus) and their hybrids. Both biotypes are expected to differ in their feeding behaviour, and pipiens/molestus hybrids are presumed to display intermediate feeding behaviour. However, the evidence for distinct feeding patterns is scarce, and to date no studies have related differences in feeding patterns to differences in host abundance. METHODS Mosquitoes were collected using CO2-baited traps. We collected blood-engorged Cx. pipiens/torrentium specimens from 12 contrasting urban sites, namely six city parks and six residential areas. Blood engorged Cx. pipiens/torrentium mosquitoes were identified to the species and biotype/hybrid level via real-time polymerase chain reaction (PCR). We performed blood meal analysis via PCR and Sanger sequencing. Additionally, avian host communities were surveyed via vocal sounds and/or visual observation. RESULTS We selected 64 blood-engorged Cx. pipiens/torrentium mosquitoes of which we successfully determined the host origin of 55 specimens. Of these, 38 belonged to biotype pipiens, 14 were pipiens/molestus hybrids and the identity of three specimens could not be determined. No blood-engorged biotype molestus or Cx. torrentium specimens were collected. We observed no differences in feeding patterns between biotype pipiens and pipiens/molestus hybrids across different habitats. Avian community composition differed between city parks and residential areas, whereas overall avian abundance did not differ between the two habitat types. CONCLUSIONS Our results show the following: (1) Cx. pipiens s.s. feeding patterns did not differ between city parks and residential areas, regardless of whether individuals were identified as biotype pipiens or pipiens/molestus hybrids. (2) We detected differences in host availability between city parks and residential areas. (3) We show that in both urban habitat types, biotype pipiens and pipiens/molestus hybrids fed on both mammalian and avian hosts. This underscores the potential role in arbovirus transmission of biotype pipiens and pipiens/molestus hybrids.
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Affiliation(s)
- Rody Blom
- Laboratory of Entomology, Plant Sciences Group, Wageningen University & Research, Wageningen, The Netherlands.
| | - Louie Krol
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
- Deltares, Utrecht, The Netherlands
| | - Melissa Langezaal
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Maarten Schrama
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Krijn B Trimbos
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Daan Wassenaar
- Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands
| | - Constantianus J M Koenraadt
- Laboratory of Entomology, Plant Sciences Group, Wageningen University & Research, Wageningen, The Netherlands
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Madeira S, Bernardino R, Osório HC, Boinas F. Mosquito (Diptera: Culicidae) Fauna of a Zoological Park in an Urban Setting: Analysis of Culex pipiens s.l. and Their Biotypes. INSECTS 2024; 15:45. [PMID: 38249051 PMCID: PMC10816151 DOI: 10.3390/insects15010045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 12/30/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024]
Abstract
Mosquito-borne diseases (MBDs) are important emerging diseases that affect humans and animals. Zoological parks can work as early warning systems for the occurrence of MBDs. In this study, we characterized the mosquito fauna captured inside Lisbon Zoo from May 2018 to November 2019. An average of 2.4 mosquitos per trap/night were captured. Five mosquito species potentially causing MBDs, including Culex pipiens biotypes, were found in the zoo. The sympatric occurrence of Culex pipiens biotypes represents a risk factor for the epizootic transmission of West Nile virus and Usutu virus. The mosquito occurrence followed the expected seasonality, with the maximum densities during summer months. However, mosquito activity was detected in winter months in low numbers. The minimum temperature and the relative humidity (RH) on the day of capture showed a positive effect on Culex pipiens abundance. Contrary, the RH the week before capture and the average precipitation the week of capture had a negative effect. No invasive species were identified, nor have flaviviruses been detected in the mosquitoes. The implementation of biosecurity measures regarding the hygiene of the premises and the strict control of all the animals entering the zoo can justify the low prevalence of mosquitoes and the absence of flavivirus-infected mosquitoes.
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Affiliation(s)
- Sara Madeira
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisboa, Portugal;
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | | | - Hugo Costa Osório
- CEVDI—INSA—Centre for Vectors and Infectious Diseases Research, National Institute of Health Doutor Ricardo Jorge, 2965-575 Águas de Moura, Portugal;
- ISAMB—Instituto de Saúde Ambiental, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Fernando Boinas
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisboa, Portugal;
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
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Negri A, Pezzali G, Pitton S, Piazzoni M, Gabrieli P, Lazzaro F, Mastrantonio V, Porretta D, Lenardi C, Caccia S, Bandi C, Epis S. MosChito rafts as a promising biocontrol tool against larvae of the common house mosquito, Culex pipiens. PLoS One 2023; 18:e0295665. [PMID: 38096210 PMCID: PMC10721080 DOI: 10.1371/journal.pone.0295665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 11/28/2023] [Indexed: 12/17/2023] Open
Abstract
Mosquito control is of paramount importance, in particular, in light of the major environmental alterations associated with human activities, from climate change to the altered distribution of pathogens, including those transmitted by Arthropods. Here, we used the common house mosquito, Culex pipiens to test the efficacy of MosChito raft, a novel tool for mosquito larval control. MosChito raft is a floating hydrogel matrix, composed of chitosan, genipin and yeast cells, as bio-attractants, developed for the delivery of a Bacillus thuringiensis israeliensis (Bti)-based bioinsecticide to mosquito larvae. To this aim, larvae of Cx. pipiens were collected in field in Northern Italy and a novel colony of mosquito species (hereafter: Trescore strain) was established. MosChito rafts, containing the Bti-based formulation, were tested on Cx. pipiens larvae from the Trescore strain to determine the doses to be used in successive experiments. Thus, bioassays with MosChito rafts were carried out under semi-field conditions, both on larvae from the Trescore strain and on pools of larvae collected from the field, at different developmental stages. Our results showed that MosChito raft is effective against Cx. pipiens. In particular, the observed mortality was over 50% after two days exposure of the larvae to MosChito rafts, and over 70-80% at days three to four, in both laboratory and wild larvae. In conclusion, our results point to the MosChito raft as a promising tool for the eco-friendly control of a mosquito species that is not only a nuisance insect but is also an important vector of diseases affecting humans and animals.
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Affiliation(s)
- Agata Negri
- Department of Biosciences, University of Milan, Milan, Italy
- Pediatric Clinical Research Center “Romeo ed Enrica Invernizzi”, University of Milan, Milan, Italy
- Italian Malaria Network, Inter University Center for Malaria Research, University of Milan, Milan, Italy
| | - Giulia Pezzali
- Department of Biosciences, University of Milan, Milan, Italy
| | - Simone Pitton
- Department of Biosciences, University of Milan, Milan, Italy
| | - Marco Piazzoni
- Department of Physics, University of Milan, Milan, Italy
- Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Paolo Gabrieli
- Department of Biosciences, University of Milan, Milan, Italy
- Pediatric Clinical Research Center “Romeo ed Enrica Invernizzi”, University of Milan, Milan, Italy
- Italian Malaria Network, Inter University Center for Malaria Research, University of Milan, Milan, Italy
| | | | | | - Daniele Porretta
- Department of Environmental Biology, “La Sapienza” University of Rome, Rome, Italy
| | | | - Silvia Caccia
- Department of Biosciences, University of Milan, Milan, Italy
| | - Claudio Bandi
- Department of Biosciences, University of Milan, Milan, Italy
- Pediatric Clinical Research Center “Romeo ed Enrica Invernizzi”, University of Milan, Milan, Italy
- Italian Malaria Network, Inter University Center for Malaria Research, University of Milan, Milan, Italy
| | - Sara Epis
- Department of Biosciences, University of Milan, Milan, Italy
- Pediatric Clinical Research Center “Romeo ed Enrica Invernizzi”, University of Milan, Milan, Italy
- Italian Malaria Network, Inter University Center for Malaria Research, University of Milan, Milan, Italy
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Ferraguti M, Dimas Martins A, Artzy-Randrup Y. Quantifying the invasion risk of West Nile virus: Insights from a multi-vector and multi-host SEIR model. One Health 2023; 17:100638. [PMID: 38024254 PMCID: PMC10665159 DOI: 10.1016/j.onehlt.2023.100638] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
The invasion of vector-borne diseases depends on the type of specific features of the vector and hosts at play. Within the Culex pipiens complex, differences in ecology, biology, and vector competence can influence the risk of West Nile virus (WNV) outbreaks. To determine which life-history traits affect WNV invasion into susceptible communities the most, we constructed an epidemiological Susceptible-Exposed-Infectious-Recovered model with three vector (eco)types, Culex pipiens pipiens, Cx. pip. molestus, and their hybrids, and two vertebrate hosts, birds (as amplifying hosts) and humans (as dead-end hosts). We investigated how differences in feeding preferences and transmission rates influenced WNV transmission across different habitats and two seasons (Spring versus Summer), to investigate the impact of increasing mosquitoes on the WNV transmission risk. Our results showed that vector feeding preferences and the transmission rate between mosquitoes and birds were the parameters that most influenced WNV invasion risk. Even though our model did not predict WNV invasion across any of the studied environments, we found that natural habitats displayed the highest susceptibility to WNV invasion. Pipiens (eco)type acted as the primary vector in all habitats. Hybrids, contrary to common opinion, showed minimal involvement in WNV transmission. However, it is important to interpret our study results with caution due to the possibility of idealized spring and summer seasons being reflected in the field-collected data. Our study could be a tool to enhance current vector surveillance and control programs by targeting specific vector types in specific environments, especially in natural habitat, which are most responsive to environmental shifts. The joint approach based on epidemiological modelling based on field collected data can help to reduce wasted time and economic costs while maximizing the efficiency of local public health authorities.
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Affiliation(s)
- Martina Ferraguti
- Departamento de Biología de la Conservación y Cambio Global, Estación Biológica de Doñana (EBD), CSIC, C/Américo Vespucio, 26, E-41092 Seville, Spain
- Department of Theoretical and Computational Ecology (TCE), Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Afonso Dimas Martins
- Department of Population Health Sciences, Faculty of Veterinary Medicine, University of Utrecht, Yalelaan 7, 3584 CL Utrecht, the Netherlands
| | - Yael Artzy-Randrup
- Department of Theoretical and Computational Ecology (TCE), Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, the Netherlands
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Morphological and Molecular Characterization Using Genitalia and CoxI Barcode Sequence Analysis of Afrotropical Mosquitoes with Arbovirus Vector Potential. DIVERSITY 2022. [DOI: 10.3390/d14110940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Potential arboviral Afrotropical mosquito vectors are underrepresented in public databases of CoxI barcode sequences. Furthermore, available CoxI sequences for many species are often not associated with voucher specimens to match the corresponding fine morphological characterization of specimens. Hence, this study focused on the characterization of Culicine mosquitoes from South Africa, Mozambique, and Angola and their classification using a complementary approach including a morphological analysis of specimens’ genitalia and phylogenetic study based on the analysis of CoxI barcode sequences using maximum likelihood and Bayesian phylogenetic inference methods, alongside Median-Joining Network and PCOORD analyses. Overall, 800 mosquitoes (652 males and 148 females) from 67 species, were analyzed. Genitalia from 663 specimens allowed the identification of 55 species of 10 genera. A total of 247 CoxI partial gene sequences corresponding to 65 species were obtained, 11 of which (Aedes capensis, Ae. mucidus, Culex andersoni, Cx. telesilla, Cx. inconspicuosus, Eretmapodites subsimplicipes, Er. quinquevittatus, Ficalbia uniformis, Mimomyia hispida, Uranotaenia alboabdominalis, and Ur. mashonaensis) are, to the best of our knowledge, provided here for the first time. The presence of Cx. pipiens ecotypes molestus and pipiens and their hybrids, as well as Cx. infula, is newly reported in the Afrotropical region. The rates of correct sequence identification using BOLD and BLASTn (≥95% identity) were 64% and 53%, respectively. Phylogenetic analysis revealed that, except for subgenus Eumelanomyia of Culex, there was support for tribes Aedini, Culicini, Ficalbiini, and Mansoniini. A divergence >2% was observed in conspecific sequences, e.g., Aedeomyia africana, Ae. cumminsii, Ae. unilineatus, Ae. metallicus, Ae. furcifer, Ae. caballus, and Mansonia uniformis. Conversely, sequences from groups and species complexes, namely, Ae. simpsoni, Ae. mcintoshi, Cx. bitaeniorhynchus, Cx. simpsoni, and Cx. pipiens were insufficiently separated. A contribution has been made to the barcode library of Afrotropical mosquitoes with associated genitalia morphological identifications.
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7
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Abstract
The northern house mosquito Culex pipiens sensu stricto is one of the most important disease vector mosquitoes in temperate zones across the northern hemisphere, responsible for the emergence of West Nile Virus over the last two decades. It comprises two ecologically distinct forms - an aboveground form, pipiens, diapauses in winter and primarily bites birds, while a belowground form, molestus, thrives year-round in subways, basements and other human-made, belowground habitats, bites mammals, and can even lay eggs without a blood meal. The two forms hybridize in some but not all places, leading to a complex ecological mosaic that complicates predictions of vectorial capacity. Moreover, the origin of the belowground molestus is contentious, with iconic populations from the London Underground subway system being held up by evolutionary biologists as a preeminent example of rapid, in situ, urban adaptation and speciation. We review the recent and historical literature on the origin and ecology of this important mosquito and its enigmatic forms. A synthesis of genetic and ecological studies spanning 100+ years clarifies a striking latitudinal gradient - behaviorally divergent and reproductively isolated forms in northern Europe gradually break down into what appear to be well-mixed, intermediate populations in North Africa. Moreover, a continuous narrative thread dating back to the original description of form molestus in Egypt in 1775 refutes the popular idea that belowground mosquitoes in London evolved in situ from their aboveground counterparts. These enigmatic mosquitoes are more likely derived from populations in the Middle East, where human-biting and other adaptations to human environments may have evolved on the timescale of millennia rather than centuries. We outline several areas for future work and discuss the implications of these patterns for public health and for our understanding of urban adaptation in the Anthropocene.
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8
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Manoj RRS, Latrofa MS, Cavalera MA, Mendoza‐Roldan JA, Maia C, Otranto D. Molecular detection of zoonotic filarioids in Culex spp. from Portugal. MEDICAL AND VETERINARY ENTOMOLOGY 2021; 35:468-477. [PMID: 33948978 PMCID: PMC8453905 DOI: 10.1111/mve.12524] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/07/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
To investigate the role of dipterans in the transmission of Onchocerca lupi and other zoonotic filarioids, samples were collected from different sites in Algarve, southern Portugal, morphologically identified and molecularly tested for filarioids. Culex sp. (72.8%) represented the predominant genus followed by Culicoides sp. (11.8%), Ochlerotatus sp. (9.7%), Culiseta sp. (4.5%), Aedes sp. (0.9%) and Anopheles sp. (0.3%). Nineteen (2.8%) specimens scored positive for filarioids, with Culex pipiens quinquefasciatus (2%) positive for Dirofilaria immitis (1.4%), Dirofilaria repens, Acanthocheilonema reconditum, Onchocerca lupi, unidentified species of Filarioidea (0.2%, each) and Onchocercidae (0.6%). Additionally, Culiseta longiareolata (6.5%), Ochlerotatus caspius (3%) and Culex laticinctus (0.2%) scored positive for unidentified Onchocercidae, A. reconditum and for O. lupi, respectively. This is the first report of the occurrence of DNA of O. lupi, D. repens and A. reconditum in Culex spp. in Portugal. Information regarding the vectors and the pathogens they transmit may help to adopt proper prophylactic and control measures.
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Affiliation(s)
- R. R. S. Manoj
- Department of Veterinary MedicineUniversity of BariValenzanoItaly
| | - M. S. Latrofa
- Department of Veterinary MedicineUniversity of BariValenzanoItaly
| | - M. A. Cavalera
- Department of Veterinary MedicineUniversity of BariValenzanoItaly
| | | | - C. Maia
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT)Universidade NOVA de Lisboa, Rua da Junqueira, 100Lisbon, 1349‐008Portugal
| | - D. Otranto
- Department of Veterinary MedicineUniversity of BariValenzanoItaly
- Faculty of Veterinary SciencesBu‐Ali Sina UniversityHamedanIran
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9
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Epstein NR, Saez K, Polat A, Davis SR, Aardema ML. The urban-adapted underground mosquito Culex pipiens form molestus maintains exogenously influenceable circadian rhythms. J Exp Biol 2021; 224:268332. [PMID: 34027981 DOI: 10.1242/jeb.242231] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/12/2021] [Indexed: 01/01/2023]
Abstract
Genes known to affect circadian rhythms (i.e. 'clock genes') also influence the photoperiodic induction of overwintering reproductive diapause in the northern house mosquito, Culex pipiens f. pipiens. This suggests that molecular changes in one or more clock genes could contribute to the inability to diapause in a second form of this mosquito, Culex pipiens f. molestus. Temperate populations of Cx. pipiens f. molestus inhabit underground locations generally devoid of predictable photoperiods. For this reason, there could be limited fitness consequences if the hypothesized molecular changes to its clock genes also eliminated this mosquito's ability to regulate circadian rhythms in response to photoperiod variation. Here, we demonstrate that in contrast to this prediction, underground derived Cx. pipiens f. molestus retain exogenously influenceable circadian rhythms. Nonetheless, our genetic analyses indicate that the gene Helicase domino (dom) has a nine-nucleotide, in-frame deletion specific to Cx. pipiens f. molestus. Previous work has shown that splice variants in this gene differentially influence circadian behavior in Drosophila melanogaster. We also find derived, non-synonymous single nucleotide polymorphisms (SNPs) in eight genes that may also affect circadian rhythms and/or diapause induction in Cx. pipiens f. molestus. Finally, four putative circadian genes were found to have no quantifiable expression during any examined life stage, suggesting potential regulatory effects. Collectively, our findings indicate that the distinct, but molecularly interconnected life-history traits of diapause induction and circadian rhythms are decoupled in Cx. pipiens f. molestus and suggest this taxon may be a valuable tool for exploring exogenously influenced phenotypes in mosquitoes more broadly.
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Affiliation(s)
- Natalie R Epstein
- Department of Biology, Montclair State University, 1 Normal Avenue, Montclair, NJ 07043, USA
| | - Kevin Saez
- Department of Biology, Montclair State University, 1 Normal Avenue, Montclair, NJ 07043, USA
| | - Asya Polat
- Department of Biology, Montclair State University, 1 Normal Avenue, Montclair, NJ 07043, USA
| | - Steven R Davis
- Division of Invertebrate Zoology, American Museum of Natural History, 200 Central Park West New York, NY 10024-5102, USA
| | - Matthew L Aardema
- Department of Biology, Montclair State University, 1 Normal Avenue, Montclair, NJ 07043, USA.,Sackler Institute for Comparative Genomics , American Museum of Natural History, 200 Central Park West, New York, NY 10024-5102, USA
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Chagas CRF, Harl J, Valkiūnas G. Co-infections of Plasmodium relictum lineages pSGS1 and pGRW04 are readily distinguishable by broadly used PCR-based protocols, with remarks on global distribution of these malaria parasites. Acta Trop 2021; 217:105860. [PMID: 33587942 DOI: 10.1016/j.actatropica.2021.105860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 01/05/2021] [Accepted: 02/07/2021] [Indexed: 12/25/2022]
Abstract
Plasmodium relictum is the most common generalist avian malaria parasite, which was reported in over 300 bird species of different orders, particularly often in passerines. This malaria infection is often severe in non-accustomed avian hosts. Currently, five distinct cytochrome b gene lineages have been assigned to P. relictum, with the lineages pSGS1 and pGRW04 being the most common. Based on molecular screenings, the transmission of these two parasite lineages might occur in sympatry, particularly often in sub-Saharan Africa, but they also have been reported to have different areas of transmission globally, with the lineages pSGS1 and pGRW04 being of low (if at all) transmission in huge regions of Americas and Europe, respectively. It remains unclear why these lineages are more often reported in some geographical areas, even though their susceptible vertebrate hosts and vectors are present globally. Co-infections of malaria parasites and other haemosporidians belonging to different species and subgenera are prevalent and even predominate in many bird populations, however, PCR-based protocols using commonly used primers often do not read such co-infections. Because information about the sensitivity of these protocols to read co-infections of the lineages pSGS1 and pGRW04 is absent, this study aimed to unravel this issue experimentally. Blood samples of birds experimentally infected with the single parasite lineages pSGS1 and pGRW04 were used to prepare various combinations of mixes, which were tested by two PCR-based protocols, which have been often used in current avian malaria research. Single infections of the same lineages were used as controls. Careful examination of the sequence electropherograms showed the presence of clear double peaks on polymorphic sites, indicating co-infections. This experiment shows that the broadly used PCR-based protocols can readily distinguish co-infections of these parasite lineages. In other words, the available information about patterns of the geographical distribution of the P. relictum lineages pSGS1 and pGRW04 likely mirrors the existing epidemiological situation but is not a result of the bias due to preferable DNA amplification of one of these lineages during their possible co-infections. This calls for further ecological research aiming determination of factors associated with the transmission of the lineages pSGS1 and pGRW04 in different regions of the globe.
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11
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Dörge DD, Cunze S, Schleifenbaum H, Zaenker S, Klimpel S. An investigation of hibernating members from the Culex pipiens complex (Diptera, Culicidae) in subterranean habitats of central Germany. Sci Rep 2020; 10:10276. [PMID: 32581278 PMCID: PMC7314823 DOI: 10.1038/s41598-020-67422-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 06/03/2020] [Indexed: 01/05/2023] Open
Abstract
The Culex pipiens complex encompasses five species and subspecies of the genus Culex. Over time, a multitude of morphologically indistinguishable species has been assigned to this complex with several species being classified as important vectors for different diseases. Some species of this complex hibernate in subterranean habitats, and it has been proven that viruses can survive this phase of hibernation. However, studies focusing on the environmental requirements, ecology and spatial and temporal distribution patterns of mosquitos in underground habitats are sparse. Here, we investigate the main environmental factors and dependencies of Culex, considering the number of individuals and survival probabilities in underground habitats during the winter months. Methods. Since the State of Hesse, Germany harbors about 3500 to 4000 subterranean shelters ample availability of subterranean habitats there provides a good opportunity to conduct detailed investigations of the Culex pipiens complex. In this study, we identified a sample of 727 specimens of overwintering females within the Culex pipiens complex from 52 different underground sites collected over a period of 23 years using qPCR. A complete data set of samplings of hibernating mosquitos from 698 subterranean habitats in Central Germany over the same period was available to study the spatial and temporal patterns and the effect of temperature and precipitation conditions on these hibernating populations using a generalized linear model (GLM). Results. Our qPCR-results show, similar to aboveground studies of mosquitos, that Culex pipiens pipiens and Culex torrentium occur sympatrically. On the other hand, Culex pipiens molestus occurred very rarely. The GLM revealed no shifts in species composition over time, but different preferences for subterranean hibernacula, chemical effects on overwintering populations as well as effects of annual and seasonal mean temperature and precipitation during the active phase from March to November. Cx. p. pipiens and Cx. torrentium are the most common species within Hessian caves and other underground habitats during winter. They co-occur with different frequency without any patterns in species composition. Weather conditions influence the number of overwintering mosquitos during the activity phase. Depending on cave parameters, the number of mosquitos decreases during the winter months.
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Affiliation(s)
- Dorian D Dörge
- Institute for Ecology, Evolution and Diversity, Goethe-University, Max-von-Laue-Str. 13, 60439, Frankfurt/Main, Germany.
| | - Sarah Cunze
- Institute for Ecology, Evolution and Diversity, Goethe-University, Max-von-Laue-Str. 13, 60439, Frankfurt/Main, Germany
| | - Henrik Schleifenbaum
- Institute for Ecology, Evolution and Diversity, Goethe-University, Max-von-Laue-Str. 13, 60439, Frankfurt/Main, Germany
| | - Stefan Zaenker
- Hesse Federation for Cave and Karst Research, Königswarter Str. 2a, 36039, Fulda, Germany
| | - Sven Klimpel
- Institute for Ecology, Evolution and Diversity, Goethe-University, Max-von-Laue-Str. 13, 60439, Frankfurt/Main, Germany.,Senckenberg Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, 60325, Frankfurt/Main, Germany
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12
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Yurchenko AA, Masri RA, Khrabrova NV, Sibataev AK, Fritz ML, Sharakhova MV. Genomic differentiation and intercontinental population structure of mosquito vectors Culex pipiens pipiens and Culex pipiens molestus. Sci Rep 2020; 10:7504. [PMID: 32371903 PMCID: PMC7200692 DOI: 10.1038/s41598-020-63305-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
Understanding the population structure and mechanisms of taxa diversification is important for organisms responsible for the transmission of human diseases. Two vectors of West Nile virus, Culex pipiens pipiens and Cx. p. molestus, exhibit epidemiologically important behavioral and physiological differences, but the whole-genome divergence between them was unexplored. The goal of this study is to better understand the level of genomic differentiation and population structures of Cx. p. pipiens and Cx. p. molestus from different continents. We sequenced and compared the whole genomes of 40 individual mosquitoes from two locations in Eurasia and two in North America. Principal Component, ADMIXTURE, and neighbor joining analyses of the nuclear genomes identified two major intercontinental, monophyletic clusters of Cx. p. pipiens and Cx. p. molestus. The level of genomic differentiation between the subspecies was uniform along chromosomes. The ADMIXTURE analysis determined signatures of admixture in Cx. p. pipens populations but not in Cx. p. molestus populations. Comparison of mitochondrial genomes among the specimens showed a paraphyletic origin of the major haplogroups between the subspecies but a monophyletic structure between the continents. Thus, our study identified that Cx. p. molestus and Cx. p. pipiens represent different evolutionary units with monophyletic origin that have undergone incipient ecological speciation.
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Affiliation(s)
- Andrey A Yurchenko
- Department of Entomology and the Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, USA.,Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Kurchatov Genomics Center, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
| | - Reem A Masri
- Department of Entomology and the Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, USA
| | - Natalia V Khrabrova
- Laboratory of Ecology, Genetics, and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Anuarbek K Sibataev
- Laboratory of Ecology, Genetics, and Environment Protection, Tomsk State University, Tomsk, Russia
| | - Megan L Fritz
- Department of Entomology, University of Maryland, College Park, USA
| | - Maria V Sharakhova
- Department of Entomology and the Fralin Life Sciences Institute, Virginia Polytechnic and State University, Blacksburg, USA. .,Laboratory of Evolutionary Genomics of Insects, the Federal Research Center Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia. .,Laboratory of Ecology, Genetics, and Environment Protection, Tomsk State University, Tomsk, Russia.
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13
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Assaid N, Mousson L, Moutailler S, Arich S, Akarid K, Monier M, Beck C, Lecollinet S, Failloux AB, Sarih M. Evidence of circulation of West Nile virus in Culex pipiens mosquitoes and horses in Morocco. Acta Trop 2020; 205:105414. [PMID: 32088277 DOI: 10.1016/j.actatropica.2020.105414] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/19/2020] [Accepted: 02/19/2020] [Indexed: 01/05/2023]
Abstract
West Nile virus (WNV) is one of the most widely distributed mosquito-borne viruses in the world. In North Africa, it causes human cases of meningoencephalitis with fatalities in Algeria and in Tunisia, whereas only horses were affected in Morocco. The aims of this study were to detect WNV in mosquitoes and to determine seroprevalence of WNV in Moroccan horses by the detection of IgG antibodies. A total of 1455 mosquitoes belonging to four different species were grouped by collection site, date, and sex with 10 specimens per pool and tested for 38 arboviruses using a high-throughput chip based on the BioMark Dynamic array system. Out of 146 mosquito pools tested, one pool was positive for WNV. This positive pool was confirmed by real time RT-PCR. The serosurvey showed that 33.7% (31/92) of horses were positive for competitive enzyme-linked immunosorbent assay (cELISA) test. The flavivirus-sphere microsphere immnoassay (MIA) test, targeting three flaviviruses (WNV, Usutu virus (USUV) and Tick borne encephalitic virus (TBEV)) showed that 23 sera out of 31 were positive for WNV, two for USUV, two for USUV or WNV, and four for an undetermined flavivirus. Virus neutralization tests with USUV and WNV showed that 28 of 31 sera were positive for WNV and all sera were negative for USUV. This study reports, for the first time, the detection of WNV from Culex pipiens mosquitoes in Morocco and its circulation among horses. This highlights that the detection of arboviruses in mosquitoes could serve as an early warning signal of a viral activity to prevent future outbreaks in animals and humans.
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Affiliation(s)
- Najlaa Assaid
- Institut Pasteur du Maroc, Service de Parasitologie et des Maladies Vectorielles, Place Louis Pasteur, Casablanca 20360, Morocco; Molecular Genetics and Immunophysiopathology Research Team, Health and Environment Laboratory, Aïn Chock Faculty of Sciences, University of Hassan II Casablanca (UH2C), Casablanca, Morocco.
| | - Laurence Mousson
- Institut Pasteur, Department of Virology, Arboviruses and Insect Vectors, 25-28 rue du Docteur Roux, Paris 75724, France.
| | - Sara Moutailler
- UMR BIPAR, Animal Health Laboratory, INRAE, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, Maisons-Alfort, France.
| | - Soukaina Arich
- Institut Pasteur du Maroc, Service de Parasitologie et des Maladies Vectorielles, Place Louis Pasteur, Casablanca 20360, Morocco.
| | - Khadija Akarid
- Molecular Genetics and Immunophysiopathology Research Team, Health and Environment Laboratory, Aïn Chock Faculty of Sciences, University of Hassan II Casablanca (UH2C), Casablanca, Morocco.
| | - Maëlle Monier
- UMR1161 Virologie, INRAE, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, Maisons-Alfort, France.
| | - Cécile Beck
- UMR1161 Virologie, INRAE, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, Maisons-Alfort, France.
| | - Sylvie Lecollinet
- UMR1161 Virologie, INRAE, ANSES, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, Maisons-Alfort, France.
| | - Anna-Bella Failloux
- Institut Pasteur, Department of Virology, Arboviruses and Insect Vectors, 25-28 rue du Docteur Roux, Paris 75724, France.
| | - M'hammed Sarih
- Institut Pasteur du Maroc, Service de Parasitologie et des Maladies Vectorielles, Place Louis Pasteur, Casablanca 20360, Morocco.
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14
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Redmond SN, Sharma A, Sharakhov I, Tu Z, Sharakhova M, Neafsey DE. Linked-read sequencing identifies abundant microinversions and introgression in the arboviral vector Aedes aegypti. BMC Biol 2020; 18:26. [PMID: 32164699 PMCID: PMC7068900 DOI: 10.1186/s12915-020-0757-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 02/21/2020] [Indexed: 11/17/2022] Open
Abstract
Background Aedes aegypti is the principal mosquito vector of Zika, dengue, and yellow fever viruses. Two subspecies of Ae. aegypti exhibit phenotypic divergence with regard to habitat, host preference, and vectorial capacity. Chromosomal inversions have been shown to play a major role in adaptation and speciation in dipteran insects and would be of great utility for studies of Ae. aegypti. However, the large and highly repetitive genome of Ae. aegypti makes it difficult to detect inversions with paired-end short-read sequencing data, and polytene chromosome analysis does not provide sufficient resolution to detect chromosome banding patterns indicative of inversions. Results To characterize chromosomal diversity in this species, we have carried out deep Illumina sequencing of linked-read (10X Genomics) libraries in order to discover inversion loci as well as SNPs. We analyzed individuals from colonies representing the geographic limits of each subspecies, one contact zone between subspecies, and a closely related sister species. Despite genome-wide SNP divergence and abundant microinversions, we do not find any inversions occurring as fixed differences between subspecies. Many microinversions are found in regions that have introgressed and have captured genes that could impact behavior, such as a cluster of odorant-binding proteins that may play a role in host feeding preference. Conclusions Our study shows that inversions are abundant and widely shared among subspecies of Aedes aegypti and that introgression has occurred in regions of secondary contact. This library of 32 novel chromosomal inversions demonstrates the capacity for linked-read sequencing to identify previously intractable genomic rearrangements and provides a foundation for future population genetics studies in this species.
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Affiliation(s)
- Seth N Redmond
- Institute of Vector Borne Disease, Monash University, Melbourne, Australia. .,Harvard TH Chan School of Public Health, Boston, MA, USA.
| | - Atashi Sharma
- Fralin Life Science Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Igor Sharakhov
- Fralin Life Science Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Zhijian Tu
- Fralin Life Science Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Maria Sharakhova
- Fralin Life Science Institute, Virginia Polytechnic and State University, Blacksburg, VA, USA
| | - Daniel E Neafsey
- Harvard TH Chan School of Public Health, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
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15
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Cardo MV, Rubio A, Junges MT, Vezzani D, Carbajo AE. A rural-urban latitudinal study of the distributions of Culex quinquefasciatus and Culex pipiens bioforms in their southernmost sympatric fringe. MEDICAL AND VETERINARY ENTOMOLOGY 2020; 34:34-43. [PMID: 31411773 DOI: 10.1111/mve.12400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/10/2019] [Accepted: 07/28/2019] [Indexed: 06/10/2023]
Abstract
Mosquitoes grouped in the complex Culex pipiens L. (Diptera: Culicidae) are important vectors of medical and veterinary diseases. In the South American sympatric region, Cx. pipiens and Culex quinquefasciatus Say coexist and potentially hybridize. To identify key drivers of their geographical distribution, mosquito immatures were collected from flower vases of eight urban/rural cemetery pairs within a 5° latitudinal transect along Buenos Aires Province, Argentina. The specimens were identified by molecular methods and their relative proportion modelled as a function of environmental variables. At the beginning of the warm season, northern and southern cemeteries presented exclusively Cx. quinquefasciatus and Cx. pipiens, respectively, with different proportions of both at mid latitudes. By the end of the summer, Cx. quinquefasciatus was present throughout the study area, exclusively in 11 of the 16 cemeteries both rural and urban, whereas Cx. pipiens was predominant only in the southernmost pair. Mean annual temperature, photoperiod variability and time of the season were key drivers of their distributions. All specimens of Cx. pipiens were identified as form molestus and no hybrids were recognized. The reported distribution patterns and the potential absence of Cx. pipiens f. pipiens and hybrids are discussed, along with their implications in disease transmission.
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Affiliation(s)
- M V Cardo
- Ecología de Enfermedades Transmitidas por Vectores (2eTV), Instituto de Investigación e Ingeniería Ambiental, UNSAM, CONICET, San Martín, Prov. de Buenos Aires, Argentina
- Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA-CIC), Tandil, Prov. de Buenos Aires, Argentina
| | - A Rubio
- Ecología de Enfermedades Transmitidas por Vectores (2eTV), Instituto de Investigación e Ingeniería Ambiental, UNSAM, CONICET, San Martín, Prov. de Buenos Aires, Argentina
- Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA-CIC), Tandil, Prov. de Buenos Aires, Argentina
| | - M T Junges
- Ecología de Enfermedades Transmitidas por Vectores (2eTV), Instituto de Investigación e Ingeniería Ambiental, UNSAM, CONICET, San Martín, Prov. de Buenos Aires, Argentina
- Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA-CIC), Tandil, Prov. de Buenos Aires, Argentina
| | - D Vezzani
- Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA-CIC), Tandil, Prov. de Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - A E Carbajo
- Ecología de Enfermedades Transmitidas por Vectores (2eTV), Instituto de Investigación e Ingeniería Ambiental, UNSAM, CONICET, San Martín, Prov. de Buenos Aires, Argentina
- Instituto Multidisciplinario sobre Ecosistemas y Desarrollo Sustentable, Facultad de Ciencias Exactas, Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA-CIC), Tandil, Prov. de Buenos Aires, Argentina
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16
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Francuski L, Gojković N, Krtinić B, Milankov V. The diagnostic utility of sequence-based assays for the molecular delimitation of the epidemiologically relevant Culex pipiens pipiens taxa (Diptera: Culicidae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2019; 109:752-761. [PMID: 30968784 DOI: 10.1017/s0007485319000105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The northern house mosquito (Culex pipiens pipiens L.) is a vector of several important pathogens and comprises two epidemiologically distinct ecotypes (molestus Forskål and pipiens). The delimitation of its ecotypes is a crucial, yet controversial step in vector surveillance due to varying diagnostic values of different characters. Therefore, we reviewed the success of a diagnostic assay based on the mitochondrial cytochrome c oxidase subunit I locus (COI) by analyzing previously published sequences of molestus and pipiens sampled in different geographical areas. Next, by genotyping individuals from Northern Serbia at this locus, we additionally assessed whether genetic structure of urban and rural Cx. p. pipiens ecotypes corresponded to the admixture pattern. Finally, to account for the different susceptibility of genetic markers to introgression, we also analyzed genetic structuring based on the ribosomal internal transcribed spacer 2 (ITS2). No latitude-dependent differentiation of Cx. p. pipiens ecotypes was found at a global level, with the COI assay further failing to accurately identify molestus and pipiens ecotypes. Likewise, both individual- (BAPS) and population-based (analysis of molecular variance and FST estimates) methods showed no significant urban/rural genetic differentiation in Serbia, indicating unhindered gene flow between different Cx. p. pipiens habitat types. The findings challenge the previous instances of Cx. p. pipiens ecotype identification, while also spotlighting the vectorial capacity of their hybrid offspring.
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Affiliation(s)
- L Francuski
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
| | - N Gojković
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
| | - B Krtinić
- Ciklonizacija, Primorska 76, 21000 Novi Sad, Serbia
| | - V Milankov
- Department of Biology and Ecology, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 2, 21000 Novi Sad, Serbia
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17
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Hickner PV, Mori A, Rund SSC, Sheppard AD, Cunningham JM, Chadee DD, Duffield GE, Severson DW. QTL Determining Diel Flight Activity in Male Culex pipiens Mosquitoes. J Hered 2019; 110:310-320. [PMID: 30668763 PMCID: PMC6503456 DOI: 10.1093/jhered/esz003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/14/2019] [Indexed: 12/26/2022] Open
Abstract
Members of the Culex pipiens complex differ in physiological traits that facilitate their survival in diverse environments. Assortative mating within the complex occurs in some regions where autogenous (the ability to lay a batch of eggs without a blood meal) and anautogenous populations are sympatric, and differences in mating behaviors may be involved. For example, anautogenous populations mate in flight/swarms, while autogenous populations often mate at rest. Here, we characterized flight activity of males and found that anautogenous strain males were crepuscular, while autogenous strain males were crepuscular and nocturnal, with earlier activity onset times. We conducted quantitative trait locus (QTL) mapping to explore the genetic basis of circadian chronotype (crepuscular vs. crepuscular and nocturnal) and time of activity onset. One major-effect QTL was identified for chronotype, while 3 QTLs were identified for activity onset. The highest logarithm of the odds (LOD) score for the chronotype QTL coincides with a chromosome 3 marker that contains a 15-nucleotide indel within the coding region of the canonical clock gene, cryptochrome 2. Sequencing of this locus in 7 different strains showed that the C-terminus of CRY2 in the autogenous forms contain deletions not found in the anautogenous forms. Consequently, we monitored activity in constant darkness and found males from the anautogenous strain exhibited free running periods of ~24 h while those from the autogenous strain were ~22 h. This study provides novel insights into the genetic basis of flight behaviors that likely reflect adaptation to their distinct ecological niches.
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Affiliation(s)
- Paul V Hickner
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
| | - Akio Mori
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
| | - Samuel S C Rund
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, UK
| | - Aaron D Sheppard
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
| | - Joanne M Cunningham
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
| | - Dave D Chadee
- Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad, West Indies
| | - Giles E Duffield
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
| | - David W Severson
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN
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18
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Koenraadt CJM, Möhlmann TWR, Verhulst NO, Spitzen J, Vogels CBF. Effect of overwintering on survival and vector competence of the West Nile virus vector Culex pipiens. Parasit Vectors 2019; 12:147. [PMID: 30917854 PMCID: PMC6437999 DOI: 10.1186/s13071-019-3400-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 03/15/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND West Nile virus (WNV) is a mosquito-borne virus that is mainly transmitted among birds by Culex pipiens mosquitoes. The species Cx. pipiens consists of two biotypes named pipiens and molestus, which together can form hybrids. One of the major distinctions between the biotypes is their overwintering behaviour. Adults of biotype pipiens diapause during winter, whereas biotype molestus remains actively blood-feeding. Diapausing may affect survival and vector competence of biotype pipiens. The aims of this study were therefore to identify the biotype composition of diapausing Cx. pipiens mosquitoes, to quantify survival throughout the autumn and winter months, and to determine effects of overwintering on vector competence of emerging Cx. pipiens mosquitoes for WNV. METHODS Diapausing mosquitoes were collected at two typical overwintering locations in the Netherlands. A selection of Cx. pipiens mosquitoes was identified to biotype using real-time PCR. Survival of diapausing Cx. pipiens mosquitoes during autumn and winter was monitored by placing cages with either field-collected or laboratory-reared females in houses and sheds. Vector competence of field-collected (diapausing) and laboratory-reared (non-diapausing) Cx. pipiens mosquitoes was determined to gain insight in the effect of overwintering on WNV transmission. RESULTS The majority (92%) of diapausing Cx. pipiens females were identified as biotype pipiens. More than 70% of diapausing Cx. pipiens mosquitoes was able to survive for more than four months in sheds, whereas diapausing in houses resulted in 100% mortality in that same period. In contrast, non-diapausing Cx. pipiens biotype pipiens mosquitoes reared in the laboratory died within a week in both houses and sheds. Vector competence of Cx. pipiens mosquitoes that had diapaused during the autumn and winter months was comparable to non-diapausing laboratory-reared mosquitoes. CONCLUSIONS This study confirms that the majority of Cx. pipiens mosquitoes in their typical overwintering site belongs to the pipiens biotype. It shows that more than two-third of diapausing Cx. pipiens mosquitoes is able to survive winter under sheltered winter conditions. Finally, vector competence for WNV of mosquitoes that emerge from overwintering sites is not affected by their relatively old age.
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Affiliation(s)
- Constantianus J M Koenraadt
- Laboratory of Entomology, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands.
| | - Tim W R Möhlmann
- Laboratory of Entomology, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands
| | - Niels O Verhulst
- National Centre for Vector Entomology, Institute of Parasitology, Vetsuisse Faculty, University of Zürich, Winterthurerstrasse 266A, 8057, Zurich, Switzerland
| | - Jeroen Spitzen
- Laboratory of Entomology, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands
| | - Chantal B F Vogels
- Laboratory of Entomology, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, P.O. Box 208034, New Haven, CT, 06510, USA
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19
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Gomard Y, Cornuault J, Licciardi S, Lagadec E, Belqat B, Dsouli N, Mavingui P, Tortosa P. Evidence of multiple colonizations as a driver of black fly diversification in an oceanic island. PLoS One 2018; 13:e0202015. [PMID: 30096163 PMCID: PMC6086440 DOI: 10.1371/journal.pone.0202015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 07/26/2018] [Indexed: 11/19/2022] Open
Abstract
True oceanic islands typically host reduced species diversity together with high levels of endemism, which make these environmental set-ups ideal for the exploration of species diversification drivers. In the present study, we used black fly species (Diptera: Simuliidae) from Reunion Island as a model to highlight the main drivers of insect species diversification in this young and remote volcanic island located in the Southwestern Indian Ocean. Using local and regional (Comoros and Seychelles archipelagos) samples as well as specimens from continental Africa, we tested the likelihood of two distinct scenarios, i.e. multiple colonizations vs. in-situ diversification. For this, posterior odds were used to test whether species from Reunion did form a monophyletic group and we estimated divergence times between species. Three out of the four previously described Reunion black fly species could be sampled, namely Simulium ruficorne, Simulium borbonense and Simulium triplex. The phylogenies based on nuclear and mitochondrial markers showed that S. ruficorne and S. borbonense are the most closely related species. Interestingly, we report a probable mitochondrial introgression between these two species although they diverged almost six million years ago. Finally, we showed that the three Reunion species did not form a monophyletic group, and, combined with the molecular datation, the results indicated that Reunion black fly diversity resulted from multiple colonization events. Thus, multiple colonizations, rather than in-situ diversification, are likely responsible for an important part of black fly diversity found on this young Darwinian island.
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Affiliation(s)
- Yann Gomard
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), INSERM 1187, CNRS 9192, IRD 249, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- * E-mail:
| | - Josselin Cornuault
- Department of Biodiversity and Conservation, Real Jardín Botánico, RJB-CSIC, Madrid, Spain
| | - Séverine Licciardi
- CIRAD, UMR ASTRE, Sainte-Clotilde, La Réunion, France
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- Groupement d’Intérêt Public Cyclotron Reunion Océan Indien (GIP CYROI), Sainte-Clotilde, La Réunion, France
| | - Erwan Lagadec
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), INSERM 1187, CNRS 9192, IRD 249, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
| | - Boutaïna Belqat
- Department of Biology, Faculty of Sciences, University Abdelmalek Essaâdi, Tétouan, Morocco
| | - Najla Dsouli
- Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien (CRVOI), Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
| | - Patrick Mavingui
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), INSERM 1187, CNRS 9192, IRD 249, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
- Université de Lyon, Lyon, France; Université Lyon 1, Villeurbanne, France; CNRS, UMR 5557, Ecologie Microbienne, Villeurbanne, France; INRA, UMR1418, Villeurbanne, France
| | - Pablo Tortosa
- Université de La Réunion, UMR PIMIT (Processus Infectieux en Milieu Insulaire Tropical), INSERM 1187, CNRS 9192, IRD 249, Plateforme Technologique CYROI, Sainte-Clotilde, La Réunion, France
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20
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The Role of Culex pipiens L. (Diptera: Culicidae) in Virus Transmission in Europe. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15020389. [PMID: 29473903 PMCID: PMC5858458 DOI: 10.3390/ijerph15020389] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 11/17/2022]
Abstract
Over the past three decades, a range of mosquito-borne viruses that threaten public and veterinary health have emerged or re-emerged in Europe. Mosquito surveillance activities have highlighted the Culex pipiens species complex as being critical for the maintenance of a number of these viruses. This species complex contains morphologically similar forms that exhibit variation in phenotypes that can influence the probability of virus transmission. Critical amongst these is the choice of host on which to feed, with different forms showing different feeding preferences. This influences the ability of the mosquito to vector viruses and facilitate transmission of viruses to humans and domestic animals. Biases towards blood-feeding on avian or mammalian hosts have been demonstrated for different Cx. pipiens ecoforms and emerging evidence of hybrid populations across Europe adds another level of complexity to virus transmission. A range of molecular methods based on DNA have been developed to enable discrimination between morphologically indistinguishable forms, although this remains an active area of research. This review provides a comprehensive overview of developments in the understanding of the ecology, behaviour and genetics of Cx. pipiens in Europe, and how this influences arbovirus transmission.
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How often do mosquitoes bite humans in southern England? A standardised summer trial at four sites reveals spatial, temporal and site-related variation in biting rates. Parasit Vectors 2017; 10:420. [PMID: 28915829 PMCID: PMC5602952 DOI: 10.1186/s13071-017-2360-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 09/01/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND This field-based study examined the abundance and species complement of mosquitoes (Diptera: Culicidae) attracted to humans at four sites in the United Kingdom (UK). The study used a systematic approach to directly measure feeding by mosquitoes on humans at multiple sites and using multiple volunteers. Quantifying how frequently humans are bitten in the field by mosquitoes is a fundamental parameter in assessing arthropod-borne virus transmission. METHODS Human landing catches were conducted using a standardised protocol by multiple volunteers at four rural sites between July and August 2013. Collections commenced two hours prior to sunset and lasted for a total of four hours. To reduce bias occurring due to collection point or to the individual attractiveness of the volunteer to mosquitoes, each collection was divided into eight collection periods, with volunteers rotated by randomised Latin square design between four sampling points per site. While the aim was to collect mosquitoes prior to feeding, the source of blood meals from any engorged specimens was also identified by DNA barcoding. RESULTS Three of the four sites yielded human-biting mosquito populations for a total of 915 mosquitoes of fifteen species/species groups. Mosquito species composition and biting rates differed significantly between sites, with individual volunteers collecting between 0 and 89 mosquitoes (over 200 per hour) of up to six species per collection period. Coquillettidia richiardii (Ficalbi, 1889) was responsible for the highest recorded biting rates at any one site, reaching 161 bites per hour, whilst maximum biting rates of 55 bites per hour were recorded for Culex modestus (Ficalbi, 1889). Human-biting by Culex pipiens (L., 1758) form pipiens was also observed at two sites, but at much lower rates when compared to other species. CONCLUSIONS Several mosquito species are responsible for human nuisance biting pressure in southern England, although human exposure to biting may be largely limited to evening outdoor activities. This study indicates Cx. modestus can be a major human-biting species in the UK whilst Cx. pipiens f. pipiens may show greater opportunistic human-biting than indicated by earlier studies.
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Ciota AT. West Nile virus and its vectors. CURRENT OPINION IN INSECT SCIENCE 2017; 22:28-36. [PMID: 28805636 DOI: 10.1016/j.cois.2017.05.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/01/2017] [Indexed: 06/07/2023]
Abstract
West Nile virus (WNV Flaviviridae; Flavivrus) is the most geographically widespread arbovirus in the world and the leading cause of arboviral encephalitis globally. Worldwide, WNV is maintained in an enzootic cycle between primarily Culex spp. mosquitoes and birds, with human infection and disease resulting from enzootic spillover. Dynamic and complex intrinsic and extrinsic factors contribute to the temporal and spatial variability in WNV transmission. The most current information on the relative contribution of each of these factors is reviewed and a case to incorporate detailed and localized environmental and genetic data into predictive models is presented.
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Affiliation(s)
- Alexander T Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA.
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Beji M, Rhim A, Roiz D, Bouattour A. Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia. Parasit Vectors 2017; 10:327. [PMID: 28693560 PMCID: PMC5504560 DOI: 10.1186/s13071-017-2265-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/27/2017] [Indexed: 12/16/2022] Open
Abstract
Background The Culex pipiens complex (Diptera: Culicidae) includes the most widespread mosquito species in the world. Members of this complex are the primary enzootic and epidemic vectors of the West Nile virus (genus Flavivirus) in several countries. The two recognized forms of Cx. pipiens (Linnaeus, 1758) - pipiens and molestus- exhibit behavioral and physiological differences. Natural populations of Cx. pipiens were investigated in several sites in Tunisia to evaluate the ecophysiological and molecular characteristics of their forms. Results The analysis showed the sympatric presence of Cx. pipiens forms and hybrids in all studied sites. Of all the tested larvae of Cx. pipiens, 33.5% were identified as pipiens, 30.8% were identified as molestus, and 35.6% were identified as hybrids. The molestus and hybrid forms were positively correlated with urban habitats and belowground sites while the pipiens form was positively correlated with rural habitats and aboveground sites. Autogeny was expressed in all types of habitats and breeding sites. By contrast with the microsatellite CQ11, the two molecular markers, ace-2 and cytb, did not allow differentiation between the Cx. pipiens forms. Conclusions Our study shows the ubiquitous distribution and the plasticity of the different forms of Cx. pipiens in a wide range of ecological conditions. It suggests that the behavioral traits assigned to the forms of Cx. pipiens seem to be more flexible than previously assumed. Our analysis also proves that the microsatellite CQ11 remains an efficient tool for distinguishing between Cx. pipiens forms. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2265-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marwa Beji
- Université Tunis El Manar, Institut Pasteur de Tunis, Laboratoire d'Epidémiologie et de Microbiologie Vétérinaire LR11IPT03, Service d'Entomologie Médicale, 1002, Tunis-Belvédère, Tunisia
| | - Adel Rhim
- Université Tunis El Manar, Institut Pasteur de Tunis, Laboratoire d'Epidémiologie et de Microbiologie Vétérinaire LR11IPT03, Service d'Entomologie Médicale, 1002, Tunis-Belvédère, Tunisia
| | - David Roiz
- Infectious Diseases and Vectors: Ecology, Genetics, Evolution and Control, IRD (Institut de Recherche pour le Développement), Montpellier, France
| | - Ali Bouattour
- Université Tunis El Manar, Institut Pasteur de Tunis, Laboratoire d'Epidémiologie et de Microbiologie Vétérinaire LR11IPT03, Service d'Entomologie Médicale, 1002, Tunis-Belvédère, Tunisia.
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Bravo-Barriga D, Gomes B, Almeida APG, Serrano-Aguilera FJ, Pérez-Martín JE, Calero-Bernal R, Reina D, Frontera E, Pinto J. The mosquito fauna of the western region of Spain with emphasis on ecological factors and the characterization of Culex pipiens forms. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2017; 42:136-147. [PMID: 28504431 DOI: 10.1111/jvec.12248] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/17/2017] [Indexed: 06/07/2023]
Abstract
UNLABELLED This study updates the diversity, distribution, and seasonal trends of mosquitoes in a western region of Spain, assesses ecological determinants of Culex pipiens s.l., and determines form composition of Cx. pipiens s.s. POPULATIONS A total of 1,495 mosquitoes of 16 species was collected during 2012-2013, of which Cx. pipiens s.l. and Cx. theileri were the most abundant. Five new records for An. maculipennis s.s., Orthopodomyia pulcripalpis, Aedes (Ochlerotatus) punctor, Cx. europaeus, and Cx. modestus were found for this region. Cx. pipiens density varied across weather and habitat patterns, correlating positively with high temperatures and with a preference for urbanized areas and rural areas within a proximity of ovine farms. Moreover, molecular identification by CQ11FL was performed in 467 Cx. pipiens s.s., detecting both pipiens (66%) and molestus (8.4%) forms coexisting in different habitats (urban, peri-urban and rural) aboveground with a high degree of hybridization (25.7%). The abundance of Cx. pipiens in urban areas and farms, with the presence of hybrids, may increase their capacity to act as bridge vectors for the transmission of arboviral infections. These data will be helpful for further implementation of entomological programs focused on risk assessment for arboviruses or other mosquito-borne pathogens.
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Affiliation(s)
- Daniel Bravo-Barriga
- Parasitology and Parasitic Diseases, Animal Health Department, Veterinary Faculty, University of Extremadura, Caceres, Spain
| | - Bruno Gomes
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Unidade de Parasitologia Médica, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
| | - Antonio P G Almeida
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Unidade de Parasitologia Médica, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
- Center for Viral Zoonoses, Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Francisco J Serrano-Aguilera
- Parasitology and Parasitic Diseases, Animal Health Department, Veterinary Faculty, University of Extremadura, Caceres, Spain
| | - Juan E Pérez-Martín
- Parasitology and Parasitic Diseases, Animal Health Department, Veterinary Faculty, University of Extremadura, Caceres, Spain
| | - Rafael Calero-Bernal
- Parasitology Service National Centre for Microbiology, Carlos III Institute of Health, Majadahonda, Madrid, Spain
| | - David Reina
- Parasitology and Parasitic Diseases, Animal Health Department, Veterinary Faculty, University of Extremadura, Caceres, Spain
| | - Eva Frontera
- Parasitology and Parasitic Diseases, Animal Health Department, Veterinary Faculty, University of Extremadura, Caceres, Spain
| | - João Pinto
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Unidade de Parasitologia Médica, Rua da Junqueira 100, 1349-008 Lisboa, Portugal
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Laurito M, Ayala AM, Almirón WR, Gardenal CN. Molecular identification of two Culex (Culex) species of the neotropical region (Diptera: Culicidae). PLoS One 2017; 12:e0173052. [PMID: 28235083 PMCID: PMC5325596 DOI: 10.1371/journal.pone.0173052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/14/2017] [Indexed: 01/06/2023] Open
Abstract
Culex bidens and C. interfor, implicated in arbovirus transmission in Argentina, are sister species, only distinguishable by feature of the male genitalia; however, intermediate specimens of the species in sympatry have been found. Fourth-instar larvae and females of both species share apomorphic features, and this lack of clear distinction creates problems for specific identification. Geometric morphometric traits of these life stages also do not distinguish the species. The aim of the present study was to assess the taxonomic status of C. bidens and C. interfor using two mitochondrial genes and to determine the degree of their reproductive isolation using microsatellite loci. Sequences of the ND4 and COI genes were concatenated in a matrix of 993 nucleotides and used for phylogenetic and distance analyses. Bayesian and maximum parsimony inferences showed a well resolved and supported topology, enclosing sequences of individuals of C. bidens (0.83 BPP, 73 BSV) and C. interfor (0.98 BPP, 97 BSV) in a strong sister relationship. The mean K2P distance within C. bidens and C. interfor was 0.3% and 0.2%, respectively, and the interspecific variation was 2.3%. Bayesian clustering also showed two distinct mitochondrial lineages. All sequenced mosquitoes were successfully identified in accordance with the best close match algorithm. The low genetic distance values obtained indicate that the species diverged quite recently. Most morphologically intermediate specimens of C. bidens from Córdoba were heterozygous for the microsatellite locus GT51; the significant heterozygote excess observed suggests incomplete reproductive isolation. However, C. bidens and C. interfor should be considered good species: the ventral arm of the phallosome of the male genitalia and the ND4 and COI sequences are diagnostic characters.
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Affiliation(s)
- Magdalena Laurito
- Instituto de Investigaciones Biológicas y Tecnológicas (IIByT) CONICET-UNC. Centro de Investigaciones Entomológicas de Córdoba (CIEC)—Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ana M. Ayala
- Instituto de Diversidad y Ecología Animal (IDEA) CONICET -Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Walter R. Almirón
- Instituto de Investigaciones Biológicas y Tecnológicas (IIByT) CONICET-UNC. Centro de Investigaciones Entomológicas de Córdoba (CIEC)—Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Cristina N. Gardenal
- Instituto de Diversidad y Ecología Animal (IDEA) CONICET -Universidad Nacional de Córdoba, Córdoba, Argentina
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Hesson JC, Schäfer M, Lundström JO. First report on human-biting Culex pipiens in Sweden. Parasit Vectors 2016; 9:632. [PMID: 27927233 PMCID: PMC5142352 DOI: 10.1186/s13071-016-1925-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/01/2016] [Indexed: 11/10/2022] Open
Abstract
Culex mosquitoes are vectors of several bird-hosted arboviruses that cause outbreaks in Europe, such as Sindbis virus and West Nile virus. Recently, the human-biting form of Culex pipiens, Cx. pipiens biotype molestus, was found causing big nuisance in a housing cooperative in Gothenburg in southern Sweden, confirmed by molecular identification. This is the first report of human-biting Culex in Scandinavia, signalling increased risk of arbovirus infection in northern Europe.
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Affiliation(s)
- Jenny C Hesson
- Department of Medical Biochemistry and Microbiology (IMBIM), Zoonotic Science Center, Uppsala University, Uppsala, Sweden. .,Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.
| | - Martina Schäfer
- Swedish Biological Mosquito Control Project, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden
| | - Jan O Lundström
- Department of Medical Biochemistry and Microbiology (IMBIM), Zoonotic Science Center, Uppsala University, Uppsala, Sweden.,Swedish Biological Mosquito Control Project, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden
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Vogels CBF, Möhlmann TWR, Melsen D, Favia G, Wennergren U, Koenraadt CJM. Latitudinal Diversity of Culex pipiens Biotypes and Hybrids in Farm, Peri-Urban, and Wetland Habitats in Europe. PLoS One 2016; 11:e0166959. [PMID: 27870890 PMCID: PMC5117740 DOI: 10.1371/journal.pone.0166959] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 11/07/2016] [Indexed: 01/01/2023] Open
Abstract
Despite the presence of Culex (Cx.) pipiens mosquitoes and circulation of West Nile virus (WNV), WNV outbreaks have so far not occurred in northern Europe. The species Cx. pipiens consists of two morphologically identical biotypes, pipiens and molestus, which can form hybrids. Until now, population dynamic studies of Cx. pipiens have not differentiated between biotypes and hybrids at the European scale, nor have they used comparative surveillance approaches. We therefore aimed to elucidate the relative abundance of Cx. pipiens biotypes and hybrids in three habitat types at different latitudes across Europe, using two different surveillance traps. BG-Sentinel and Mosquito-Magnet Liberty Plus traps were placed in three habitat types (farms, peri-urban, wetlands), in three European countries (Sweden, The Netherlands, Italy). Collected Cx. pipiens mosquitoes were identified to biotype with real-time PCR. Both trap types collected equal ratios of the biotypes and their hybrids. From northern to southern latitudes there was a significant decrease of pipiens and an increase of molestus. Habitat types influenced the relative ratios of biotypes and hybrids, but results were not consistent across latitudes. Our results emphasize the need to differentiate Cx. pipiens to the biotype level, especially for proper future WNV risk assessments for Europe.
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Affiliation(s)
- Chantal B. F. Vogels
- Laboratory of Entomology, Wageningen University and Research centre, Wageningen, The Netherlands
- * E-mail:
| | - Tim W. R. Möhlmann
- Laboratory of Entomology, Wageningen University and Research centre, Wageningen, The Netherlands
- IFM Theory and Modelling, Linköping University, Linköping, Sweden
| | - Diede Melsen
- Laboratory of Entomology, Wageningen University and Research centre, Wageningen, The Netherlands
| | - Guido Favia
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Uno Wennergren
- IFM Theory and Modelling, Linköping University, Linköping, Sweden
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Amara Korba R, Alayat MS, Bouiba L, Boudrissa A, Bouslama Z, Boukraa S, Francis F, Failloux AB, Boubidi SC. Ecological differentiation of members of the Culex pipiens complex, potential vectors of West Nile virus and Rift Valley fever virus in Algeria. Parasit Vectors 2016; 9:455. [PMID: 27534938 PMCID: PMC4989528 DOI: 10.1186/s13071-016-1725-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 07/25/2016] [Indexed: 12/24/2022] Open
Abstract
Background We investigated the ecological differentiation of two members of the Culex pipiens complex, Cx. p. pipiens form pipiens and Cx. p. pipiens form molestus in three sites, El-Kala, M'Sila and Tinerkouk in Algeria. These two forms are the most widespread mosquito vectors in temperate regions exhibiting important behavioural and physiological differences. Nevertheless, this group of potential vectors has been poorly studied, particularly in North Africa. Methods Ten larval populations of Cx. p. pipiens were sampled from various above- and underground habitats in three zones representing the three bioclimatic regions in Algeria. The reproduction characteristics were also investigated in the laboratory to define the rates of autogeny and stenogamy. Identification of Cx. p. pipiens members present in Algeria was achieved using a molecular analysis with the microsatellite CQ11 locus. Results We detected larvae of Cx. p. pipiens in all areas suggesting that the species is a ubiquitous mosquito well adapted to various environments. To our knowledge, this study provides the first molecular evidence of the presence of the Cx. p. pipiens form molestus and hybrids (molestus/pipiens) in Algeria with a high proportion of molestus form (48.3 %) in comparison with hybrids (36.8 %) and pipiens form (14.9 %). Conclusions Some unexpected correlations between the proportion of forms pipiens, molestus and hybrids, and mosquito biological characteristics were observed suggesting some epigenetic effects controlling Cx. p. pipiens mating and reproduction. Consequences for pathogen transmission are discussed. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1725-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Raouf Amara Korba
- Laboratoire Ecologie des Systèmes Terrestres et Aquatiques, Département de Biologie, Faculté des Sciences, Université Badji Mokhtar, Annaba, Algérie. .,Institut Pasteur d'Alger, Unité d'Entomologie Médicale, Service d'Eco-épidémiologie parasitaire et génétique des populations, Alger, Algérie.
| | - Moufida Saoucen Alayat
- Laboratoire de Biologie Animale Appliquée, Faculté des Sciences, Département de Biologie, Université Badji Mokhtar, Annaba, Algérie
| | - Lazhari Bouiba
- Institut Pasteur d'Alger, Unité d'Entomologie Médicale, Service d'Eco-épidémiologie parasitaire et génétique des populations, Alger, Algérie
| | - Abdelkarim Boudrissa
- Institut Pasteur d'Alger, Unité d'Entomologie Médicale, Service d'Eco-épidémiologie parasitaire et génétique des populations, Alger, Algérie
| | - Zihad Bouslama
- Laboratoire Ecologie des Systèmes Terrestres et Aquatiques, Département de Biologie, Faculté des Sciences, Université Badji Mokhtar, Annaba, Algérie
| | - Slimane Boukraa
- Unit of Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés 2, 5030, Gembloux, Belgium
| | - Frederic Francis
- Unit of Functional and Evolutionary Entomology, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés 2, 5030, Gembloux, Belgium
| | - Anna-Bella Failloux
- Institut Pasteur, Department of Virology, Arboviruses and Insect Vectors, Paris, France
| | - Saïd Chaouki Boubidi
- Institut Pasteur d'Alger, Unité d'Entomologie Médicale, Service d'Eco-épidémiologie parasitaire et génétique des populations, Alger, Algérie
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Stepanović S, Kosovac A, Krstić O, Jović J, Toševski I. Morphology versus DNA barcoding: two sides of the same coin. A case study of Ceutorhynchus erysimi and C. contractus identification. INSECT SCIENCE 2016; 23:638-648. [PMID: 25726808 DOI: 10.1111/1744-7917.12212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 06/04/2023]
Abstract
Genotyping of 2 well-known weevil species from the genus Ceutorhynchus (Coleoptera: Curculionidae) distributed in west Palearctic, C. erysimi and C. contractus, revealed phenotype versus genotype inconsistencies in a set of 56 specimens (25 C. erysimi and 31 C. contractus) collected from 25 locations in Serbia and Montenegro. An analysis of the mitochondrial cytochrome oxidase subunit I gene (COI), widely used as a barcoding region, and a nuclear gene, elongation factor-1α (EF-1α), revealed stable genetic divergence among these species. The average uncorrected pairwise distances for the COI and EF-1α genes were 3.8%, and 1.3%, respectively, indicating 2 genetically well-segregated species. However, the genetic data were not congruent with the phenotypic characteristics of the studied specimens. In the first place, C. erysimi genotypes were attached to specimens with phenotypic characteristics of C. contractus. Species-specific PCR-RFLP assays for the barcoding gene COI were applied for the molecular identification of 101 additional specimens of both morphospecies (33 C. erysimi and 68 C. contractus) and were found to confirm this incongruity. The discrepancy between the genetic and morphological data raises the question of the accuracy of using a barcoding approach, as it may result in misleading conclusions about the taxonomic position of the studied organism. Additionally, the typological species concept shows considerable weakness when genetic data are not supported with phenotypic characteristics as in case of asymmetric introgression, which may cause certain problems, especially in applied studies such as biological control programs in which the biological properties of the studied organisms are the main focus.
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Affiliation(s)
- Svetlana Stepanović
- Faculty of Science, Institute of Biology and Ecology, University of Kragujevac, 34000, Kragujevac, Serbia
| | - Andrea Kosovac
- Department of Plant Pests, Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia
| | - Oliver Krstić
- Department of Plant Pests, Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia
| | - Jelena Jović
- Department of Plant Pests, Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia
| | - Ivo Toševski
- Department of Plant Pests, Institute for Plant Protection and Environment, Banatska 33, 11080, Zemun, Serbia
- CABI, 1 Rue des Grillons, 2800, Delémont, Switzerland
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Zittra C, Flechl E, Kothmayer M, Vitecek S, Rossiter H, Zechmeister T, Fuehrer HP. Ecological characterization and molecular differentiation of Culex pipiens complex taxa and Culex torrentium in eastern Austria. Parasit Vectors 2016; 9:197. [PMID: 27067139 PMCID: PMC4828795 DOI: 10.1186/s13071-016-1495-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/05/2016] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Culex pipiens complex taxa differ in behaviour, ecophysiology and epidemiologic importance. Despite their epidemiologic significance, information on genetic diversity, occurrence and seasonal and spatial distribution patterns of the Cx. pipiens complex is still insufficient. Assessment of seasonal and spatial distribution patterns of Culex pipiens forms and their congener Cx. torrentium is crucial for the understanding of their vector-pathogen dynamics. METHODS Female mosquitoes were trapped from April-October 2014 twice a month for a 24-h time period with BG-sentinel traps at 24 sampling sites in eastern Austria, using carbon dioxide as attractant. Ecological forms of Cx. pipiens s.l. and their hybrids were differentiated using the CQ11 locus, and Cx. pipiens forms and their congener Cx. torrentium using the ACE-2 gene. Differential exploitation of ecological niches by Cx. pipiens forms and Cx. torrentium was analysed using likelihood ratio tests. Possible effects of environmental parameters on these taxa were tested using PERMANOVA based on distance matrices and, if significant, were modelled in nMDS ordination space to estimate non-linear relationships. RESULTS For this study, 1476 Culex spp. were sampled. Culex pipiens f. pipiens representing 87.33 % of the total catch was most abundant, followed by hybrids of both forms (5.62 %), Cx. torrentium (3.79 %) and Cx. pipiens f. molestus (3.25 %). Differences in proportional abundances were found between land cover classes. Ecological parameters affecting seasonal and spatial distribution of these taxa in eastern Austria are precipitation duration, air temperature, sunlight and the interaction term of precipitation amount and the Danube water level, which can be interpreted as a proxy for breeding habitat availability. CONCLUSIONS The Cx. pipiens complex of eastern Austria comprises both ecologically different forms, the mainly ornithophilic form pipiens and the mainly mammalophilic and anthropophilic form molestus. Heterogeneous agricultural areas as areas of coexistence may serve as hybridization zones, resulting in potential bridge vectors between birds and humans. Occurrence, seasonal and spatial distribution patterns of the Cx. pipiens complex and Cx. torrentium and the presence of hybrids between both forms were quantified for the first time in Austria. These findings will improve the knowledge of their vector-pathogen dynamics in this country.
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Affiliation(s)
- Carina Zittra
- Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Eva Flechl
- Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Michael Kothmayer
- Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Simon Vitecek
- Department of Limnology and Bio-Oceanography, University of Vienna, Vienna, Austria
| | | | | | - Hans-Peter Fuehrer
- Department of Pathobiology, Institute of Parasitology, University of Veterinary Medicine Vienna, Vienna, Austria.
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Asgharian H, Chang PL, Lysenkov S, Scobeyeva VA, Reisen WK, Nuzhdin SV. Evolutionary genomics of Culex pipiens: global and local adaptations associated with climate, life-history traits and anthropogenic factors. Proc Biol Sci 2016; 282:rspb.2015.0728. [PMID: 26085592 PMCID: PMC4590483 DOI: 10.1098/rspb.2015.0728] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We present the first genome-wide study of recent evolution in Culex pipiens species complex focusing on the genomic extent, functional targets and likely causes of global and local adaptations. We resequenced pooled samples of six populations of C. pipiens and two populations of the outgroup Culex torrentium. We used principal component analysis to systematically study differential natural selection across populations and developed a phylogenetic scanning method to analyse admixture without haplotype data. We found evidence for the prominent role of geographical distribution in shaping population structure and specifying patterns of genomic selection. Multiple adaptive events, involving genes implicated with autogeny, diapause and insecticide resistance were limited to specific populations. We estimate that about 5–20% of the genes (including several histone genes) and almost half of the annotated pathways were undergoing selective sweeps in each population. The high occurrence of sweeps in non-genic regions and in chromatin remodelling genes indicated the adaptive importance of gene expression changes. We hypothesize that global adaptive processes in the C. pipiens complex are potentially associated with South to North range expansion, requiring adjustments in chromatin conformation. Strong local signature of adaptation and emergence of hybrid bridge vectors necessitate genomic assessment of populations before specifying control agents.
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Affiliation(s)
- Hosseinali Asgharian
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Peter L Chang
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA
| | - Sergey Lysenkov
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA Department of Evolution, Moscow State University, Moscow 119991, Russia
| | | | - William K Reisen
- Center for Vectorborne Diseases, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Sergey V Nuzhdin
- Program in Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA Department of Evolution, Moscow State University, Moscow 119991, Russia St. Petersburg State Polytechnical University, Sanct Petersburg, Russia
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Simonato M, Martinez-Sañudo I, Cavaletto G, Santoiemma G, Saltarin A, Mazzon L. High genetic diversity in the Culex pipiens complex from a West Nile Virus epidemic area in Southern Europe. Parasit Vectors 2016; 9:150. [PMID: 26979749 PMCID: PMC4791856 DOI: 10.1186/s13071-016-1429-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 03/05/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Culex pipiens complex includes the most widespread mosquito species in the world. Cx. pipiens is the primary vector of the West Nile Virus (WNV) in Europe and North America. Cases of WNV have been recorded in Italy since 1998. In particular, wet areas along the Po River are considered some of the most WNV affected areas in Italy. Here, we analyzed the genetic structure of ten Cx. pipiens populations collected in the last part of the Po River including the Delta area. METHODS We assessed the genetic variability of two mitochondrial markers, cytochrome oxidase 1 (COI) and 2 (COII), for a total of 1200 bp, and one nuclear marker, a fragment of acetylcholinesterase-2 (ace-2), 502 bp long. The effect of the landscape features was evaluated comparing haplotype and nucleotide diversity with the landscape composition. RESULTS The analysis showed a high genetic diversity in both COI and COII gene fragments mainly shared by the populations in the Delta area. The COI-COII network showed that the set of haplotypes found was grouped into three main supported lineages with the higher genetic variability gathered in two of the three lineages. By contrast, ace-2 fragment did not show the same differentiation, displaying alleles grouped in a single clade. Finally, a positive correlation between mitochondrial diversity and natural wetland areas was found. CONCLUSIONS The high mitochondrial genetic diversity found in Cx. pipiens populations from the Po River Delta contrasts with the low variability of inland populations. The different patterns of genetic diversity found comparing mitochondrial and nuclear markers could be explained by factors such as differences in effective population size between markers, sex biased dispersal or lower fitness of dispersing females. Moreover, the correlation between genetic diversity and wetland areas is consistent with ecosystem stability and lack of insecticide pressure characteristic of this habitat. The mtDNA polymorphism found in the Po River Delta is even more interesting due to possible linkages between the mitochondrial lineages and different biting behaviors of the mosquitoes influencing their vector ability of arboviral infections.
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Affiliation(s)
- Mauro Simonato
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Isabel Martinez-Sañudo
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Giacomo Cavaletto
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Giacomo Santoiemma
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Andrea Saltarin
- Istituto Tecnico Agrario "O. Munerati", Via Capello 10, 45010, Sant'Apollinare, RO, Italy
| | - Luca Mazzon
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Viale dell'Università 16, 35020, Legnaro, PD, Italy.
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Shaikevich EV, Vinogradova EB, Bouattour A, Gouveia de Almeida AP. Genetic diversity of Culex pipiens mosquitoes in distinct populations from Europe: contribution of Cx. quinquefasciatus in Mediterranean populations. Parasit Vectors 2016; 9:47. [PMID: 26818097 PMCID: PMC4730663 DOI: 10.1186/s13071-016-1333-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 01/20/2016] [Indexed: 12/28/2022] Open
Abstract
Background Mosquitoes of the Culex pipiens complex are cosmopolitan, and important vectors of neglected tropical diseases, such as arbovirosis and lymphatic filariasis. Among the complex taxa, Cx. pipiens (with two forms pipiens and molestus) and Cx. quinquefasciatus are the most ubiquitous mosquitoes in temperate and tropical regions respectively. Mosquitoes of this taxa lack of morphological differences between females, but have frank behavioral and physiological differences and have different trophic preferences that influence their vectorial status. Hybridization may change the vectorial capacity of these mosquitoes, increasing vector efficiency and medical importance of resulting hybrids. Methods Culex pipiens s.l. from 35 distinct populations were investigated by the study of mtDNA, symbiotic bacterium Wolbachia pipientis, nuclear DNA and flanking region of microsatellite CQ11 polymorphism using PCR with diagnostic primers, RFLP analysis and sequencing. Results Six different mitochondrial haplotypes were revealed by sequencing of the cytochrome oxidase subunit I (COI) gene and three different Wolbachia (wPip) groups were identified. A strong association was observed between COI haplotypes/groups, wPip groups and taxa; haplogroup A and infection with wPipII appear to be typical for Cx. pipiens form pipiens, haplotype D and infection with wPipIV for form molestus, while haplogroup E, characteristic of Cx. quinquefasciatus, were correlated with wPipI and found in Cx. pipiens sl. from coastal regions of Southern Europe and Mediterranean region. Analysis of microsatellite locus and nuclear DNA revealed hybrids between Cx. pipiens form pipiens and form molestus, as well as between Cx. pipiens and Cx. quinquefasciatus, in Mediterranean populations, as opposed to Northern Europe. Phylogenetic analysis of COI sequences yielded a tree topology that supported the RFLP analysis with significant bootstrap values for haplotype D and haplogroup E. Conclusions Molecular identification provides the first evidence of the presence of hybrids between Cx. quinquefasciatus and Cx. pipiens as well as cytoplasmic introgression of Cx. quinquefasciatus into Cx. pipiens as a result of hybridization events in coastal regions of Southern Europe and Mediterranean region. Together with observed hybrids between pipiens and molestus forms, these findings point to the presence of hybrids in these areas, with consequent higher potential for disease transmission. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1333-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elena V Shaikevich
- N.I. Vavilov Institute of General Genetics, ul. Gubkina 3, 119991, Moscow, Russia.
| | - Elena B Vinogradova
- Zoological Institute, Russian Academy of Sciences, University Embankment 1, 199034, St. Petersburg, Russia.
| | - Ali Bouattour
- Laboratoire d'Epidémiologie et de Microbiologie Vétérinaire, Service d'Entomologie Médicale, Institut Pasteur de Tunis- Tunis El Manar University, Tunis, Tunisia.
| | - António Paulo Gouveia de Almeida
- Global Health and Tropical Medicine, GHTM, Medical Parasitology Unit, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira 100, 1349-008, Lisbon, Portugal. .,Extraordinary professor at ZRU, Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
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Di Luca M, Toma L, Boccolini D, Severini F, La Rosa G, Minelli G, Bongiorno G, Montarsi F, Arnoldi D, Capelli G, Rizzoli A, Romi R. Ecological Distribution and CQ11 Genetic Structure of Culex pipiens Complex (Diptera: Culicidae) in Italy. PLoS One 2016; 11:e0146476. [PMID: 26741494 PMCID: PMC4712155 DOI: 10.1371/journal.pone.0146476] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/17/2015] [Indexed: 01/05/2023] Open
Abstract
Mosquitoes in the Culex pipiens complex are considered to be involved in the transmission of a range of pathogens, including West Nile virus (WNV). Although its taxonomic status is still debated, the complex includes species, both globally distributed or with a more limited distribution, morphologically similar and characterised by different physiological and behavioural traits, which affect their ability as vectors. In many European countries, Cx. pipiens and its sibling species Culex torrentium occur in sympatry, exhibiting similar bionomic and morphological characters, but only Cx. pipiens appears to play a vector role in WNV transmission. This species consists of two biotypes, pipiens and molestus, which can interbreed when in sympatry, and their hybrids can act as WNV-bridge vectors, due to intermediate ecological features. Considering the yearly WNV outbreaks since 2008 and given the morphological difficulties in recognising species and biotypes, our aim was to molecularly identify and characterised Cx. pipiens and Cx. torrentium in Italy, using recently developed molecular assays. Culex torrentium was not detected; as in other European countries, the pipiens and molestus biotypes were widely found in sympatry with hybrids in most environments. The UPGMA cluster analysis applied to CQ11 genotypic frequencies mainly revealed two groups of Cx. pipiens populations that differed in ecological features. The high propensity of the molestus biotype to exist in hypogean environments, where the habitat’s physical characteristics hinder and preclude the gene flow, was shown. These results confirmed the CQ11 assay as a reliable diagnostic method, consistent with the ecological and physiological aspects of the populations analysed. Since the assessment of the actual role of three biotypes in the WNV circulation remains a crucial point to be elucidated, this extensive molecular screening of Cx. pipiens populations can provide new insights into the ecology of the species and may give useful indications to plan and implement WNV surveillance activities in Italy.
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Affiliation(s)
- Marco Di Luca
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
- * E-mail:
| | - Luciano Toma
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Daniela Boccolini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Francesco Severini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Giuseppe La Rosa
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Giada Minelli
- National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Gioia Bongiorno
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
| | - Fabrizio Montarsi
- Laboratory of Parasitology - Istituto Zooprofilattico Sperimentale delle Venezie, viale dell’Università 10, 35020, Legnaro, Padua, Italy
| | - Daniele Arnoldi
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010, San Michele all'Adige, Trento, Italy
| | - Gioia Capelli
- Laboratory of Parasitology - Istituto Zooprofilattico Sperimentale delle Venezie, viale dell’Università 10, 35020, Legnaro, Padua, Italy
| | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, 38010, San Michele all'Adige, Trento, Italy
| | - Roberto Romi
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, viale Regina Elena, 299, 00161, Rome, Italy
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Vogels CB, van de Peppel LJ, van Vliet AJ, Westenberg M, Ibañez-Justicia A, Stroo A, Buijs JA, Visser TM, Koenraadt CJ. Winter Activity and Aboveground Hybridization Between the Two Biotypes of the West Nile Virus VectorCulex pipiens. Vector Borne Zoonotic Dis 2015; 15:619-26. [DOI: 10.1089/vbz.2015.1820] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Chantal B.F. Vogels
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
| | | | - Arnold J.H. van Vliet
- Environmental Systems Analysis Group, Wageningen University and Research Centre, Wageningen, The Netherlands
| | - Marcel Westenberg
- Dutch National Plant Protection Organization, Wageningen, The Netherlands
| | - Adolfo Ibañez-Justicia
- Centre for Monitoring of Vectors (CMV), National Reference Centre (NRC), Netherlands Food and Consumer Product Safety Authority (NVWA), Ministry of Economic Affairs, Wageningen, The Netherlands
| | - Arjan Stroo
- Centre for Monitoring of Vectors (CMV), National Reference Centre (NRC), Netherlands Food and Consumer Product Safety Authority (NVWA), Ministry of Economic Affairs, Wageningen, The Netherlands
| | - Jan A. Buijs
- Public Health Service Amsterdam, Amsterdam, The Netherlands
| | - Tessa M. Visser
- Laboratory of Entomology, Wageningen University and Research Centre, Wageningen, The Netherlands
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Fortuna C, Remoli ME, Di Luca M, Severini F, Toma L, Benedetti E, Bucci P, Montarsi F, Minelli G, Boccolini D, Romi R, Ciufolini MG. Experimental studies on comparison of the vector competence of four Italian Culex pipiens populations for West Nile virus. Parasit Vectors 2015; 8:463. [PMID: 26383834 PMCID: PMC4574231 DOI: 10.1186/s13071-015-1067-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 09/01/2015] [Indexed: 12/25/2022] Open
Abstract
Background West Nile virus (WNV) is a vector-borne disease responsible for causing epidemics in many areas of the world. The virus is maintained in nature by an enzootic bird-mosquito-bird cycle and occasionally transmitted to other hosts, such as equines and humans. Culex species, in particular the ubiquitous species Culex pipiens is thought to play a major vector role both in enzootic and epizootic maintenance and transmission of WNV. Introduced in Europe in recent years, since 2008 WNV has been stably circulating mainly in the Northeastern regions of Italy, although sporadic equine and/or human cases, as well as WNV infected Cx. pipiens pools, have been recorded in other Italian areas. The scope of our study was to evaluate the potential competence of some Italian populations of Cx. pipiens to transmit WNV and to assess their ability for vertical transmission of the virus. For this purpose four Italian populations, from different areas, were experimentally infected. Methods After the infectious blood meal, fed females were monitored for 32 days to determine the length of viral extrinsic incubation period. WNV titre of infected mosquitoes was evaluated both by quantitative Real Time PCR and viral titration by Plaque Forming Units/ml (PFU/mL) in VERO cells. Potential Infection, Dissemination, Transmission rates (IR, DR, TR) were assessed by detection of the virus in body, legs plus wings and saliva of the fed females, respectively. Results All tested populations were susceptible to the WNV infection. The viral presence in legs and wings demonstrated the ability of WNV to disseminate in the mosquitoes. Viral RNA was detected in the saliva of tested populations. No significant differences in TR values were observed among the four studied populations. The offspring of the Cx. pipiens infected females were WNV negative. Conclusions Our study addressed an important issue in the knowledge on the complex WNV-vector relationships in Italy, indicating that all Italian Cx. pipiens populations tested exhibited vector competence for WNV. Further studies should be performed in order to better clarify the role of other factors (vector density, climatic conditions, reservoir presence etc.) in order to predict where and when WNV outbreaks could occur.
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Affiliation(s)
- Claudia Fortuna
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Maria Elena Remoli
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Marco Di Luca
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Francesco Severini
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Luciano Toma
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Eleonora Benedetti
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Paola Bucci
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Fabrizio Montarsi
- Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, PD, Italy.
| | - Giada Minelli
- National Centre for Epidemiology, Surveillance and Health Promotion, Unit of Statistics Istituto Superiore di Sanità, Rome, Italy.
| | - Daniela Boccolini
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Roberto Romi
- Unit of Vector-borne Diseases and International Health, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
| | - Maria Grazia Ciufolini
- Unit of Viral diseases and attenuated vaccine, Department of Infectious, Parasitic and Immune-Mediated Diseases Istituto Superiore di Sanità, Rome, Italy.
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Gomes B, Wilding CS, Weetman D, Sousa CA, Novo MT, Savage HM, Almeida APG, Pinto J, Donnelly MJ. Limited genomic divergence between intraspecific forms of Culex pipiens under different ecological pressures. BMC Evol Biol 2015; 15:197. [PMID: 26377220 PMCID: PMC4573496 DOI: 10.1186/s12862-015-0477-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/03/2015] [Indexed: 01/01/2023] Open
Abstract
Background Divergent selection can be a major driver of ecological speciation. In insects of medical importance, understanding the speciation process is both of academic interest and public health importance. In the West Nile virus vector Culex pipiens, intraspecific pipiens and molestus forms vary in ecological and physiological traits. Populations of each form appear to share recent common ancestry but patterns of genetic differentiation across the genome remain unknown. Here, we undertook an AFLP genome scan on samples collected from both sympatric and allopatric populations from Europe and the USA to quantify the extent of genomic differentiation between the two forms. Results The forms were clearly differentiated but each exhibited major population sub-structuring between continents. Divergence between pipiens and molestus forms from USA was higher than in both inter- and intra-continental comparisons with European samples. The proportion of outlier loci between pipiens and molestus (≈3 %) was low but consistent in both continents, and similar to those observed between sibling species of other mosquito species which exhibit contemporary gene flow. Only two of the outlier loci were shared between inter-form comparisons made within Europe and USA. Conclusion This study supports the molestus and pipiens status as distinct evolutionary entities with low genomic divergence. The low number of shared divergent loci between continents suggests a relatively limited number of genomic regions determining key typological traits likely to be driving incipient speciation and/or adaptation of molestus to anthropogenic habitats. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0477-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bruno Gomes
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisbon, Portugal. .,Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Craig S Wilding
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK. .,School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, L3 3AF, UK.
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
| | - Carla A Sousa
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisbon, Portugal.
| | - Maria T Novo
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisbon, Portugal.
| | - Harry M Savage
- Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO, 80521, USA.
| | - António P G Almeida
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisbon, Portugal.
| | - João Pinto
- Global Health & Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisbon, Portugal.
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Krida G, Rhim A, Daaboub J, Failloux AB, Bouattour A. New evidence for the potential role of Culex pipiens mosquitoes in the transmission cycle of West Nile virus in Tunisia. MEDICAL AND VETERINARY ENTOMOLOGY 2015; 29:124-128. [PMID: 25586151 DOI: 10.1111/mve.12107] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 06/04/2023]
Abstract
Physiological and molecular characteristics of natural populations of Culex pipiens Linnaeus, 1758 (Diptera: Culicidae) were investigated to elucidate how this species is potentially involved in the transmission of West Nile virus in Tunisia. A total of 215 Cx. pipiens females from 11 breeding habitats were analysed in the laboratory to estimate autogeny and stenogamy rates. They were tested individually for the locus CQ11 to distinguish between the two Cx. pipiens forms, pipiens and molestus. All tested Cx. pipiens populations were stenogamous. Females from underground breeding sites were all autogeneous, whereas females from above-ground habitats were mostly anautogeneous. Of all the females tested, 59.7% were identified as pipiens, 22.4% as molestus, and 17.9% as hybrid pipiens/molestus. Furthermore, both Cx. pipiens forms and their hybrids were found to co-occur in sympatry in all sites. The results of this study represent the first evidence that both Cx. pipiens forms and their hybrids are present in Tunisia. Because hybrids able to act as bridge vectors are present in all studied habitats, Tunisia can be considered to have a high degree of receptivity for the establishment of West Nile virus zoonotic cycles.
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Affiliation(s)
- G Krida
- Département de Protection des Plantes et de Maladies Post-Récolte, Institut National Agronomique de Tunisie, University of Carthage, Tunis, Tunisia; Laboratoire d'Épidémiologie et de Microbiologie Vétérinaire, Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
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Valkiūnas G, Žiegytė R, Palinauskas V, Bernotienė R, Bukauskaitė D, Ilgūnas M, Dimitrov D, Iezhova TA. Complete sporogony of Plasmodium relictum (lineage pGRW4) in mosquitoes Culex pipiens pipiens, with implications on avian malaria epidemiology. Parasitol Res 2015; 114:3075-85. [PMID: 25958156 DOI: 10.1007/s00436-015-4510-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 04/29/2015] [Indexed: 01/03/2023]
Abstract
Plasmodium relictum (lineage pGRW4) causes malaria in birds and is actively transmitted in countries with warm climates and also temperate regions of the New World. In Europe, the lineage pGRW4 has been frequently reported in many species of Afrotropical migrants after their arrival from wintering grounds, but is rare in European resident birds. Obstacles for transmission of this parasite in Europe have not been identified. Culex quinquefasciatus is an effective vector of pGRW4 malaria, but this mosquito is absent from temperate regions of Eurasia. It remains unclear if the lineage pGRW4 completes sporogony in European species of mosquitoes. Here we compare the sporogonic development of P. relictum (pGRW4) in experimentally infected mosquitoes Culex pipiens pipiens form molestus, C. quinquefasciatus, and Ochlerotatus cantans. The pGRW4 parasite was isolated from a garden warbler Sylvia borin, multiplied, and used to infect laboratory-reared Culex spp. and wild-caught Ochlerotatus mosquitoes by allowing them to take blood meals on infected birds. The exposed females were maintained at a mean laboratory temperature of 19 °C, which ranged between 14 °C at night and 24 °C during daytime. They were dissected on intervals to study the development of sporogonic stages. Only ookinetes developed in O. cantans; sporogonic development was abortive. The parasite completed sporogony in both Culex species, with similar patterns of development, and sporozoites were reported in the salivary glands 16 days after infection. The presence of sporogonic stages of the lineage pGRW4 in mosquitoes was confirmed by PCR-based testing of (1) the sporozoites present in salivary glands and (2) the single oocysts, which were obtained by laser microdissection from infected mosquito midguts. This study shows that P. relictum (pGRW4) completes sporogony in C. p. pipiens at relatively low temperatures. We conclude that there are no restrictions for spreading this bird infection in Europe from the point of view of vector availability and temperature necessary for sporogony. Other factors should be considered and were discussed for the explanation of rare reports of this malaria parasite in Europe.
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Marcantonio M, Rizzoli A, Metz M, Rosà R, Marini G, Chadwick E, Neteler M. Identifying the environmental conditions favouring West Nile Virus outbreaks in Europe. PLoS One 2015; 10:e0121158. [PMID: 25803814 PMCID: PMC4372576 DOI: 10.1371/journal.pone.0121158] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/28/2015] [Indexed: 11/29/2022] Open
Abstract
West Nile Virus (WNV) is a globally important mosquito borne virus, with significant implications for human and animal health. The emergence and spread of new lineages, and increased pathogenicity, is the cause of escalating public health concern. Pinpointing the environmental conditions that favour WNV circulation and transmission to humans is challenging, due both to the complexity of its biological cycle, and the under-diagnosis and reporting of epidemiological data. Here, we used remote sensing and GIS to enable collation of multiple types of environmental data over a continental spatial scale, in order to model annual West Nile Fever (WNF) incidence across Europe and neighbouring countries. Multi-model selection and inference were used to gain a consensus from multiple linear mixed models. Climate and landscape were key predictors of WNF outbreaks (specifically, high precipitation in late winter/early spring, high summer temperatures, summer drought, occurrence of irrigated croplands and highly fragmented forests). Identification of the environmental conditions associated with WNF outbreaks is key to enabling public health bodies to properly focus surveillance and mitigation of West Nile virus impact, but more work needs to be done to enable accurate predictions of WNF risk.
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Affiliation(s)
- Matteo Marcantonio
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
- * E-mail:
| | - Annapaola Rizzoli
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Markus Metz
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Roberto Rosà
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Giovanni Marini
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
| | - Elizabeth Chadwick
- School of Bioscience, Cardiff University, Cardiff, Wales, United Kingdom
| | - Markus Neteler
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Italy
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Ferreira CAC, de Pinho Mixão V, Novo MTLM, Calado MMP, Gonçalves LAP, Belo SMD, de Almeida APG. First molecular identification of mosquito vectors of Dirofilaria immitis in continental Portugal. Parasit Vectors 2015; 8:139. [PMID: 25886610 PMCID: PMC4369802 DOI: 10.1186/s13071-015-0760-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/20/2015] [Indexed: 11/12/2022] Open
Abstract
Background Canine dirofilariasis due to Dirofilaria immitis is known to be endemic in continental Portugal. However, information about the transmitting mosquito species is still scarce, with only Culex theileri identified to date, albeit with L1-2, through dissection. This study was carried out to investigate the potential vectors of Dirofilaria spp. in continental Portugal. Methods Mosquitoes were collected in three distinct seasons (Summer, Autumn and Spring), 2011–2013, in three districts. CDC traps and indoor resting collections were carried out in the vicinity of kennels. Mosquitoes were kept under controlled conditions for 7 days to allow the development of larval stages of Dirofilaria spp.. DNA extraction was performed separately for both head+thorax and abdomen in order to differentiate infective and infected specimens, respectively, in pools, grouped according to the species and collection site (1–40 specimen parts/pool), and examined by PCR using pan-filarial specific primers. Mosquito densities were compared using non-parametric tests. Dirofilaria development units (DDU) were estimated. Results In total, 9156 female mosquitoes, from 11 different species, were captured. Mosquito densities varied among the 3 districts, according to capture method, and were generally higher in the second year of collections. From 5866 specimens screened by PCR, 23 head+thorax and 41 abdomens pools, corresponding to 54 mosquitoes were found positive for D. immitis DNA. These belonged to 5 species: Culex (Cux) theileri (estimated rate of infection (ERI)=0.71%), Cx. (Cux) pipiens f. pipiens and f. molestus (ERI=0.5%), Anopheles (Ano) maculipennis s.l. (ERI=3.12%), including An. (Ano) atroparvus, Aedes (Och) caspius (ERI=3.73%) and Ae. (Och) detritus s.l. (ERI=4.39%). All but Cx. pipiens, had at least one infective specimen. No D. repens infected specimens were found. Infection rates were: 3.21% in Coimbra, 1.22% in Setúbal and 0.54% in Santarém. DDU were at least 117/year in the study period. Conclusions Culex theileri, Cx. pipiens, An. maculipennis s.l. An. atroparvus, Ae.caspius and Ae. detritus s.l. were identified as potential vectors of D. immitis in three districts of Portugal, from Spring to Autumn, in 5 of the 6 collection dates in 2011–2013. Implications for transmission, in the context of climate changes, and need for prophylactic measures, are discussed.
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Affiliation(s)
- Cátia Alexandra Costa Ferreira
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal.
| | - Verónica de Pinho Mixão
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal.
| | - Maria Teresa Lourenço Marques Novo
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal.
| | - Maria Manuela Palmeiro Calado
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal.
| | - Luzia Augusta Pires Gonçalves
- International Public Health and Biostatistics Unit, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal. .,Centro de Estatística e Aplicações da Universidade de Lisboa, Faculdade de Ciências da Universidade de Lisboa, Bloco C6 - Piso 4, Campo Grande, 1749-016, Lisboa, Portugal.
| | - Silvana Maria Duarte Belo
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal.
| | - António Paulo Gouveia de Almeida
- Medical Parasitology Unit, Medical Parasitology & Microbiology Unit-UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008, Lisboa, Portugal. .,Zoonosis Research Unit, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
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Žiegytė R, Bernotienė R, Bukauskaitė D, Palinauskas V, Iezhova T, Valkiūnas G. Complete sporogony of Plasmodium relictum (lineages pSGS1 and pGRW11) in mosquito Culex pipiens pipiens form molestus, with implications to avian malaria epidemiology. J Parasitol 2015; 100:878-82. [PMID: 24979183 DOI: 10.1645/13-469.1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Plasmodium parasites (Plasmodiidae) cause malaria in many species of terrestrial vertebrates and are transmitted mainly by mosquitoes (Culicidae). Avian malaria is often caused by Plasmodium relictum , a cosmopolitan hemosporidian infection. Numerous genetic lineages of P. relictum have been described. However, it remains unclear if these lineages can be transmitted by Culex pipiens pipiens form molestus, which is widespread but has been insufficiently investigated as a possible vector of avian malaria. The aim of this study was to test experimentally if 2 common P. relictum lineages complete sporogony in the experimentally infected insects. The mosquitoes were cultivated under laboratory conditions. Unfed females were allowed to take blood meals on domestic canaries experimentally infected with the lineages pSGS1 and pGRW11 of P. relictum . These lineages are widespread and cause malaria in many species of birds. Infected female flies were examined for sporogonic development of each parasite lineage. Both exposed groups were maintained under the same laboratory conditions. Mosquitoes were dissected at intervals, and the midguts and salivary glands were prepared in order to detect sporogonic stages. Numerous ookinetes, oocysts, and sporozoites of both parasite lineages were observed. Polymerase chain reaction confirmed the presence of corresponding parasite lineages in the experimentally infected insects. Sporogonic stages of both lineages were morphologically similar and developed synchronously in this mosquito; however, the lineage pGRW11 developed a significantly greater number of oocysts than did the lineage pSGS1. This study shows that Culex p. pipiens f. molestus is susceptible to 2 widespread lineages of P. relictum and worth more attention in avian malaria epidemiology. We recommend C. p. pipiens f. molestus for experimental research of avian malaria parasites, principally because it willingly takes blood meals on birds and because it is easy to establish and maintain new colonies of this insect under laboratory conditions using wild-sampled eggs, larvae, or imago.
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Affiliation(s)
- Rita Žiegytė
- Institute of Ecology, Nature Research Centre, Akademijos 2, Vilnius 21, LT-08412, Lithuania
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Krtinić B, Ludoški J, Milankov V. Multi-character approach reveals a discordant pattern of phenotypic variation during ontogeny in Culex pipiens biotypes (Diptera: Culicidae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2015; 105:129-138. [PMID: 25424880 DOI: 10.1017/s0007485314000832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Culex (Culex) pipiens s.l. (Diptera: Culicidae) comprises two distinct biotypes, pipiens ('rural') and molestus ('urban'), both of which are thought to have differing capacities due to different host preferences. To better understand West Nile encephalitis epidemiology and improve risk assessment, local distinction between these forms is essential. This study assesses phenotypic variation at larval and adult stages of 'urban' and 'rural' biotypes of the species by complementary use of meristic, univariate and multivariate traits analyzed by traditional and geometric morphometrics. Third- and fourth-instar larvae from a broad area of the city of Novi Sad (Serbia) were collected and reared in the laboratory. After adult eclosion, the sex of each larva was recorded based on the sex of the corresponding adult. Examination of the association between variations of larval traits revealed contrasting variations regarding pecten spines vs. siphonal size and siphonal shape in the 'rural' biotype. Siphons of larvae collected in marshes and forest ecosystems outside urban areas were found to be the largest, but possessed the smallest number of pecten spines. In addition, statistically significant female-biased sexual dimorphism was observed in siphonal size, wing size and wing shape. Finally, we propose that an integrative approach is essential in delimitation of Cx. pipiens s.l. biotypes, since their differentiation was not possible based solely on larval and adult traits. Our findings shed light on the phenotypic plasticity important for population persistence in the changing environment of these medically important taxa.
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Affiliation(s)
- B Krtinić
- Ciklonizacija,Primorska 76,21000 Novi Sad,Serbia
| | - J Ludoški
- Department of Biology and Ecology,Faculty of Sciences,University of Novi Sad,Trg Dositeja Obradovića 2,21000 Novi Sad,Serbia
| | - V Milankov
- Department of Biology and Ecology,Faculty of Sciences,University of Novi Sad,Trg Dositeja Obradovića 2,21000 Novi Sad,Serbia
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Turell MJ, Dohm DJ, Fonseca DM. Comparison of the Potential for Different Genetic Forms in the Culex pipiens Complex in North America to Transmit Rift Valley Fever Virus. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2014; 30:253-259. [PMID: 25843130 DOI: 10.2987/14-6441r.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rift Valley fever virus (RVFV), a mosquito-borne virus, has been responsible for large outbreaks in Africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. Culex pipiens was implicated as the principal vector of the Egyptian outbreak in 1977 that affected about 200,000 people. In the northern USA, Cx. pipiens occurs both as a mix of forms pipiens and molestus (i.e., US Culex pipiens) as well as pure Cx. pipiens form molestus, the latter mostly in underground locations such as sewers and basements. In order to understand the potential risk of spread of RVFV in the USA, we compared their relative abilities to transmit RVFV in the laboratory. After feeding on hamsters with high viremias, >10(9) plaque-forming units (PFU)/ml, both US Cx. pipiens and Cx. pipiens form molestus were highly susceptible to infection (∼80%) and about 20% of each form developed a disseminated infection. In contrast, when fed on a hamster with a moderate viremia, 10(7.5) PFU/ml, US Cx. pipiens were significantly (P < 0.001) more susceptible (84%) than were the pure form molestus (47%). Similarly, dissemination rates were significantly (P = 0.0261) higher in US Cx. pipiens (34%) than they were in pure Cx. pipiens form molestus (10%). These results underscore differences in vector competence between genetic forms in the Cx. pipiens complex but also indicate that if RVFV were to arrive in the USA, competent vectors abound in the highly urbanized Northeast.
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Affiliation(s)
- Michael J Turell
- 2 Virology Division, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702-5011
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Angêlla AF, Salgueiro P, Gil LHS, Vicente JL, Pinto J, Ribolla PEM. Seasonal genetic partitioning in the neotropical malaria vector, Anopheles darlingi. Malar J 2014; 13:203. [PMID: 24885508 PMCID: PMC4059831 DOI: 10.1186/1475-2875-13-203] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/21/2014] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles darlingi is the main malaria mosquito vector in the Amazonia region. In spite of being considered a riverine, forest-dwelling species, this mosquito is becoming more abundant in peri-urban areas, increasing malaria risk. This has been associated with human-driven environmental changes such as deforestation. Methods Microsatellites were used to characterize A. darlingi from seven localities along the Madeira River, Rondônia (Brazil), collected in the early and late periods of the rainy season. Results Two genetically distinct subpopulations were detected: one (subpopulation A) was associated with the late rainfall period and seems to be ecologically closer to the typical forest A. darlingi; the other (subpopulation B) was associated with the early rainfall period and is probably more adapted to drier conditions by exploiting permanent anthropogenic breeding sites. Results suggest also a pattern of asymmetric introgression, with more subpopulation A alleles introgressed into subpopulation B. Both subpopulations (and admixed mosquitoes) presented similar malaria infection rates, highlighting the potential for perennial malaria transmission in the region. Conclusions The co-occurrence of two genetically distinct subpopulations of A. darlingi adapted to different periods of rainfall may promote a more perennial transmission of malaria throughout the year. These findings, in a context of strong environmental impact due to deforestation and dam construction, have serious implications for malaria epidemiology and control in the Amazonian region.
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Affiliation(s)
| | | | | | | | | | - Paulo E M Ribolla
- Departamento de Parasitologia, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Neto", Botucatu, SP, Brasil.
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Osório HC, Zé-Zé L, Amaro F, Nunes A, Alves MJ. Sympatric occurrence of Culex pipiens (Diptera, Culicidae) biotypes pipiens, molestus and their hybrids in Portugal, Western Europe: feeding patterns and habitat determinants. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:103-109. [PMID: 23786327 DOI: 10.1111/mve.12020] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 02/26/2013] [Accepted: 03/18/2013] [Indexed: 06/02/2023]
Abstract
Culex (Culex) pipiens (Diptera: Culicidae) has two recognized biotypes, pipiens and molestus, which differ in physiology and behaviour; this difference may influence vectorial capacity for West Nile virus (WNV). Our goal was first to determine the presence of Cx. pipiens populations in 31 locations in Portugal and to subsequently analyse their host-feeding preferences and habitat determinants. Molecular identification of Cx. pipiens forms and their hybrids was performed in 97 females; bloodmeal sources were identified in 59 engorged specimens. Overall, 61.9% of specimens were identified as Cx. pipiens f. pipiens, 20.6% as Cx. pipiens f. molestus, and 17.5% as hybrid forms. Culex pipiens f. pipiens fed preferentially on birds, and Cx. pipiens f. molestus on humans. Hybrid forms fed mostly on birds, but human bloodmeals were common. With reference to habitat, Cx. pipiens f. pipiens and hybrid forms were positively correlated with peri-urban habitats. Our results confirm the sympatric presence of different Cx. pipiens biotypes in 14 of the 31 locations studied. Peri-urban areas were a common habitat of all biotypes and may represent zones of hybridization. The feeding preferences and sympatric distribution of the Cx. pipiens biotypes observed in Portugal favour the epizootic circulation of WNV and the occurrence of disease outbreaks of WNV.
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Affiliation(s)
- H C Osório
- Centre for Vectors and Infectious Diseases Research Dr. Francisco Cambournac, National Health Institute Dr. Ricardo Jorge, Águas de Moura, Portugal
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Marka A, Diamantidis A, Papa A, Valiakos G, Chaintoutis SC, Doukas D, Tserkezou P, Giannakopoulos A, Papaspyropoulos K, Patsoula E, Badieritakis E, Baka A, Tseroni M, Pervanidou D, Papadopoulos NT, Koliopoulos G, Tontis D, Dovas CI, Billinis C, Tsakris A, Kremastinou J, Hadjichristodoulou C. West Nile virus state of the art report of MALWEST Project. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:6534-610. [PMID: 24317379 PMCID: PMC3881129 DOI: 10.3390/ijerph10126534] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 11/16/2022]
Abstract
During the last three years Greece is experiencing the emergence of West Nile virus (WNV) epidemics. Within this framework, an integrated surveillance and control programme (MALWEST project) with thirteen associate partners was launched aiming to investigate the disease and suggest appropriate interventions. One out of seven work packages of the project is dedicated to the State of the Art report for WNV. Three expert working groups on humans, animals and mosquitoes were established. Medical databases (PubMed, Scopus) were searched together with websites: e.g., WHO, CDC, ECDC. In total, 1,092 relevant articles were initially identified and 258 of them were finally included as references regarding the current knowledge about WNV, along with 36 additional sources (conference papers, reports, book chapters). The review is divided in three sections according to the fields of interest: (1) WNV in humans (epidemiology, molecular characteristics, transmission, diagnosis, treatment, prevention, surveillance); (2) WNV in animals (epidemiological and transmission characteristics concerning birds, horses, reptiles and other animal species) and (3) WNV in mosquitoes (control, surveillance). Finally, some examples of integrated surveillance programmes are presented. The introduction and establishment of the disease in Greece and other European countries further emphasizes the need for thorough research and broadening of our knowledge on this viral pathogen.
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Affiliation(s)
- Andriani Marka
- Department of Microbiology, Faculty of Medicine, University of Athens, Athens 11527, Greece; E-mail:
| | - Alexandros Diamantidis
- Laboratory of Entomology and Agricultural Zoology, School of Agricultural Sciences, University of Thessaly, Volos 38446, Greece; E-mails: (A.D.); (N.T.P.)
| | - Anna Papa
- National Reference Center for Arboviruses, Department of Microbiology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mail:
| | - George Valiakos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Serafeim C. Chaintoutis
- Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mails: (S.C.C.); (C.I.D.)
| | - Dimitrios Doukas
- Laboratory of Pathology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (D.D.); (D.T.)
| | - Persefoni Tserkezou
- Department of Microbiology, Faculty of Medicine, University of Athens, Athens 11527, Greece; E-mail:
| | - Alexios Giannakopoulos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Konstantinos Papaspyropoulos
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Eleni Patsoula
- Department of Parasitology, Entomology and Tropical Diseases, National School of Public Health, Athens 11521, Greece; E-mail:
| | - Evangelos Badieritakis
- Laboratory of Biological Control of Pesticides, Benaki Phytopathological Institute, Athens 14561, Greece; E-mails: (E.B.); (G.K.)
| | - Agoritsa Baka
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Maria Tseroni
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Danai Pervanidou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
| | - Nikos T. Papadopoulos
- Laboratory of Entomology and Agricultural Zoology, School of Agricultural Sciences, University of Thessaly, Volos 38446, Greece; E-mails: (A.D.); (N.T.P.)
| | - George Koliopoulos
- Laboratory of Biological Control of Pesticides, Benaki Phytopathological Institute, Athens 14561, Greece; E-mails: (E.B.); (G.K.)
| | - Dimitrios Tontis
- Laboratory of Pathology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (D.D.); (D.T.)
| | - Chrysostomos I. Dovas
- Laboratory of Microbiology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; E-mails: (S.C.C.); (C.I.D.)
| | - Charalambos Billinis
- Laboratory of Microbiology and Parasitology, Faculty of Veterinary Medicine, University of Thessaly, Karditsa 43100, Greece; E-mails: (G.V); (A.G.); (K.P.); (C.B.)
| | - Athanassios Tsakris
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +30-2410-565-007; Fax: +30-2410-565-051
| | - Jenny Kremastinou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens 15123, Greece; E-mails: (A.B.); (M.T.); (D.P.); (J.K.)
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Rona LDP, Carvalho-Pinto CJ, Peixoto AA. Evidence for the occurrence of two sympatric sibling species within the Anopheles (Kerteszia) cruzii complex in southeast Brazil and the detection of asymmetric introgression between them using a multilocus analysis. BMC Evol Biol 2013; 13:207. [PMID: 24063651 PMCID: PMC3850420 DOI: 10.1186/1471-2148-13-207] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 08/21/2013] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Anopheles (Kerteszia) cruzii (Diptera: Culicidae) is a primary vector of human and simian malaria parasites in southern and southeastern Brazil. Earlier studies using chromosome inversions, isoenzymes and a number of molecular markers have suggested that An. cruzii is a species complex. RESULTS In this study, a multilocus approach using six loci, three circadian clock genes and three encoding ribosomal proteins, was carried out to investigate in more detail the genetic differentiation between the An. cruzii populations from Florianópolis-Santa Catarina (southern Brazil) and Itatiaia-Rio de Janeiro States (southeastern Brazil). The analyses were performed first comparing Florianópolis and Itatiaia, and then comparing the two putative sympatric incipient species from Itatiaia (Itatiaia A and Itatiaia B). The analysis revealed high FST values between Florianópolis and Itatiaia (considering Itatiaia A and B together) and also between the sympatric Itatiaia A and Itatiaia B, irrespective of their function. Also, using the IM program, no strong indication of migration was found between Florianópolis and Itatiaia (considering Itatiaia A and B together) using all loci together, but between Itatiaia A and Itatiaia B, the results show evidence of migration only in the direction of Itatiaia B. CONCLUSIONS The results of the multilocus analysis indicate that Florianópolis and Itatiaia represent different species of the An. cruzii complex that diverged around 0.6 Mya, and also that the Itatiaia sample is composed of two sympatric incipient species A and B, which diverged around 0.2 Mya. Asymmetric introgression was found between the latter two species despite strong divergence in some loci.
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Affiliation(s)
- Luísa D P Rona
- Universidade Federal do Rio de Janeiro, Polo de Xerém, Estrada de Xerém 27, Duque de Caxias 25245-390, RJ, Brazil.
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First nationwide surveillance of Culex pipiens complex and Culex torrentium mosquitoes demonstrated the presence of Culex pipiens biotype pipiens/molestus hybrids in Germany. PLoS One 2013; 8:e71832. [PMID: 24039724 PMCID: PMC3770594 DOI: 10.1371/journal.pone.0071832] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 07/03/2013] [Indexed: 11/19/2022] Open
Abstract
Mosquitoes and other arthropods may transmit medically important pathogens, in particular viruses such as West Nile virus. The presence of suitable hosts and competent vectors for those zoonotic viruses is essential for an enzootic transmission, which is a prerequisite for epidemics. To establish reliable risk projections, it is an urgent need for an exact identification of mosquito species, which is especially challenging in the case of sibling species, such as Culex. pipiens pipiens biotypes pipiens and molestus. To facilitate detection of different Culex pipiens forms and their hybrids we established a multiplex real-time PCR. Culex pipiens samples were obtained by egg raft collection and rearing until imago stage or adult sampling using CO2 baited traps and gravid traps. In total, we tested more than 16,500 samples collected all over Germany in the years 2011 and 2012. The predominant species in Germany are Culex pipiens pipiens biotype pipiens and Culex. torrentium, but we also detected Culex pipiens pipiens biotype molestus and hybrids of the two pipiens biotypes at sites where both species occur sympatrically. This report of a potentially important bridge vector for West Nile virus might have major impact in the risk projections for West Nile virus in Germany.
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Dumas E, Atyame CM, Milesi P, Fonseca DM, Shaikevich EV, Unal S, Makoundou P, Weill M, Duron O. Population structure of Wolbachia and cytoplasmic introgression in a complex of mosquito species. BMC Evol Biol 2013; 13:181. [PMID: 24006922 PMCID: PMC3846486 DOI: 10.1186/1471-2148-13-181] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/28/2013] [Indexed: 12/31/2022] Open
Abstract
Background The maternally inherited bacterium Wolbachia often acts as a subtle parasite that manipulates insect reproduction, resulting potentially in reproductive isolation between host populations. Whilst distinct Wolbachia strains are documented in a group of evolutionarily closely related mosquitoes known as the Culex pipiens complex, their impact on mosquito population genetics remains unclear. To this aim, we developed a PCR-RFLP test that discriminates the five known Wolbachia groups found in this host complex. We further examined the Wolbachia genetic diversity, the variability in the coinherited host mitochondria and their partitioning among members of the Cx. pipiens complex, in order to assess the impact of Wolbachia on host population structure. Results There was a strong association between Wolbachia and mitochondrial haplotypes indicating a stable co-transmission in mosquito populations. Despite evidence that members of the Cx. pipiens complex are genetically distinct on the basis of nuclear DNA, the association of Wolbachia and mtDNA with members of the Cx. pipiens complex were limited. The Wolbachia wPip-I group, by far the most common, was associated with divergent Cx. pipiens members, including Cx. quinquefasciatus, Cx. pipiens pipiens form pipiens and Cx. pipiens pipiens form molestus. Four other wPip groups were also found in mosquito populations and all were shared between diverse Cx. pipiens members. Conclusion This data overall supports the hypothesis that wPip infections, and their allied mitochondria, are associated with regular transfers between Cx. pipiens members rather than specific host associations. Overall, this is suggestive of a recent and likely ongoing cytoplasmic introgression through hybridization events across the Cx. pipiens complex.
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Affiliation(s)
- Emilie Dumas
- Institut des Sciences de l'Evolution, UMR5554 CNRS, Université Montpellier 2, 34095 Montpellier cedex 05, France.
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