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Linthout C, Martins AD, de Wit M, Delecroix C, Abbo SR, Pijlman GP, Koenraadt CJM. The potential role of the Asian bush mosquito Aedes japonicus as spillover vector for West Nile virus in the Netherlands. Parasit Vectors 2024; 17:262. [PMID: 38886805 PMCID: PMC11181672 DOI: 10.1186/s13071-024-06279-5] [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: 01/22/2024] [Accepted: 04/13/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND In recent years the Asian bush mosquito Aedes japonicus has invaded Europe, including the Netherlands. This species is a known vector for a range of arboviruses, possibly including West Nile virus (WNV). As WNV emerged in the Netherlands in 2020, it is important to investigate the vectorial capacity of mosquito species present in the Netherlands to estimate the risk of future outbreaks and further spread of the virus. Therefore, this study evaluates the potential role of Ae. japonicus in WNV transmission and spillover from birds to dead-end hosts in the Netherlands. METHODS We conducted human landing collections in allotment gardens (Lelystad, the Netherlands) in June, August and September 2021 to study the diurnal and seasonal host-seeking behaviour of Ae. japonicus. Furthermore, their host preference in relation to birds using live chicken-baited traps was investigated. Vector competence of field-collected Ae. japonicus mosquitoes for two isolates of WNV at two different temperatures was determined. Based on the data generated from these studies, we developed a Susceptible-Exposed-Infectious-Recovered (SEIR) model to calculate the risk of WNV spillover from birds to humans via Ae. japonicus, under the condition that the virus is introduced and circulates in an enzootic cycle in a given area. RESULTS Our results show that Ae. japonicus mosquitoes are actively host seeking throughout the day, with peaks in activity in the morning and evening. Their abundance in August was higher than in June and September. For the host-preference experiment, we documented a small number of mosquitoes feeding on birds: only six blood-fed females were caught over 4 full days of sampling. Finally, our vector competence experiments with Ae. japonicus compared to its natural vector Culex pipiens showed a higher infection and transmission rate when infected with a local, Dutch, WNV isolate compared to a Greek isolate of the virus. Interestingly, we also found a small number of infected Cx. pipiens males with virus-positive leg and saliva samples. CONCLUSIONS Combining the field and laboratory derived data, our model predicts that Ae. japonicus could act as a spillover vector for WNV and could be responsible for a high initial invasion risk of WNV when present in large numbers.
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Affiliation(s)
- Charlotte Linthout
- Department of Entomology, Wageningen University & Research, Wageningen, the Netherlands.
| | - Afonso Dimas Martins
- Department of Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Mariken de Wit
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, the Netherlands
| | - Clara Delecroix
- Quantitative Veterinary Epidemiology, Wageningen University & Research, Wageningen, the Netherlands
- Department of Environmental Sciences, Wageningen University & Research, Wageningen, the Netherlands
| | - Sandra R Abbo
- Department of Virology, Wageningen University & Research, Wageningen, the Netherlands
| | - Gorben P Pijlman
- Department of Virology, Wageningen University & Research, Wageningen, the Netherlands
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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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Snyman J, Snyman LP, Buhler KJ, Villeneuve CA, Leighton PA, Jenkins EJ, Kumar A. California Serogroup Viruses in a Changing Canadian Arctic: A Review. Viruses 2023; 15:1242. [PMID: 37376542 DOI: 10.3390/v15061242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/24/2023] [Accepted: 05/18/2023] [Indexed: 06/29/2023] Open
Abstract
The Arctic is warming at four times the global rate, changing the diversity, activity and distribution of vectors and associated pathogens. While the Arctic is not often considered a hotbed of vector-borne diseases, Jamestown Canyon virus (JCV) and Snowshoe Hare virus (SSHV) are mosquito-borne zoonotic viruses of the California serogroup endemic to the Canadian North. The viruses are maintained by transovarial transmission in vectors and circulate among vertebrate hosts, both of which are not well characterized in Arctic regions. While most human infections are subclinical or mild, serious cases occur, and both JCV and SSHV have recently been identified as leading causes of arbovirus-associated neurological diseases in North America. Consequently, both viruses are currently recognised as neglected and emerging viruses of public health concern. This review aims to summarise previous findings in the region regarding the enzootic transmission cycle of both viruses. We identify key gaps and approaches needed to critically evaluate, detect, and model the effects of climate change on these uniquely northern viruses. Based on limited data, we predict that (1) these northern adapted viruses will increase their range northwards, but not lose range at their southern limits, (2) undergo more rapid amplification and amplified transmission in endemic regions for longer vector-biting seasons, (3) take advantage of northward shifts of hosts and vectors, and (4) increase bite rates following an increase in the availability of breeding sites, along with phenological synchrony between the reproduction cycle of theorized reservoirs (such as caribou calving) and mosquito emergence.
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Affiliation(s)
- Jumari Snyman
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Louwrens P Snyman
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Kayla J Buhler
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Carol-Anne Villeneuve
- Research Group on Epidemiology of Zoonoses and Public Health (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Patrick A Leighton
- Research Group on Epidemiology of Zoonoses and Public Health (GREZOSP), Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC J2S 2M2, Canada
| | - Emily J Jenkins
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Anil Kumar
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
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Stelder JJ, Mihalca AD, Olesen AS, Kjær LJ, Boklund AE, Rasmussen TB, Marinov M, Alexe V, Balmoş OM, Bødker R. Potential mosquito vector attraction to- and feeding preferences for pigs in Romanian backyard farms. Front Vet Sci 2023; 9:1046263. [PMID: 36686172 PMCID: PMC9846066 DOI: 10.3389/fvets.2022.1046263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/08/2022] [Indexed: 01/05/2023] Open
Abstract
Introduction Mosquitoes either biologically or mechanically transmit various vector-borne pathogens affecting pigs. Mosquito species display a wide variety of host preference, as well as host attraction and behaviours. Mosquito species attraction rates to- and feeding rates on pigs or other potential hosts, as well as the seasonal abundance of the mosquito species affects their pathogen transmission potential. Methods We caught mosquitoes in experimental cages containing pigs situated in Romanian backyard farms. The host species of blood meals were identified with PCR and sequencing. Results High feeding preferences for pigs were observed in Aedes vexans (90%), Anopheles maculipennis (80%) and Culiseta annulata (72.7%). However, due to a high abundance in the traps, Culex pipiens/torrentium were responsible for 37.9% of all mosquito bites on pigs in the Romanian backyards, despite low feeding rates on pigs in the cages (18.6%). We also found that other predominantly ornithophilic mosquito species, as well as mosquitoes that are already carrying a blood meal from a different (mammalian) host, were attracted to backyard pigs or their enclosure. Discussion These results indicate that viraemic blood carrying, for instance, African swine fever virus, West-Nile virus or Japanese encephalitis virus could be introduced to these backyard pig farms and therefore cause an infection, either through subsequent feeding, via ingestion by the pig or by environmental contamination.
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Affiliation(s)
- Jonno Jorn Stelder
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Copenhagen, Denmark,*Correspondence: Jonno Jorn Stelder ✉
| | - Andrei Daniel Mihalca
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - Ann Sofie Olesen
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
| | - Lene Jung Kjær
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Copenhagen, Denmark
| | - Anette Ella Boklund
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Copenhagen, Denmark
| | - Thomas Bruun Rasmussen
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
| | - Mihai Marinov
- Department of Biodiversity Conservation and Sustainable Use of Natural Resources, Danube Delta National Institute for Research and Development, Tulcea, Romania
| | - Vasile Alexe
- Department of Biodiversity Conservation and Sustainable Use of Natural Resources, Danube Delta National Institute for Research and Development, Tulcea, Romania
| | - Oana Maria Balmoş
- Department of Parasitology and Parasitic Diseases, University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca, Cluj-Napoca, Romania
| | - René Bødker
- Section for Animal Welfare and Disease Control, Department of Veterinary and Animal Sciences, Copenhagen University, Copenhagen, Denmark
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Autochthonous Transmission of West Nile Virus by a New Vector in Iran, Vector-Host Interaction Modeling and Virulence Gene Determinants. Viruses 2020; 12:v12121449. [PMID: 33339336 PMCID: PMC7766443 DOI: 10.3390/v12121449] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/27/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023] Open
Abstract
Using molecular techniques and bioinformatics tools, we studied the vector-host interactions and the molecular epidemiology of West Nile virus (WNV) in western Iran. Mosquitoes were collected during 2017 and 2018. DNA typing assays were used to study vector-host interactions. Mosquitoes were screened by RT-PCR for the genomes of five virus families. WNV-positive samples were fully sequenced and evolutionary tree and molecular architecture were constructed by Geneious software and SWISS-MODEL workspace, respectively. A total of 5028 mosquito specimens were collected and identified. The most prevalent species was Culex (Cx.) pipiens complex (57.3%). Analysis of the blood-feeding preferences of blood-fed mosquitoes revealed six mammalian and one bird species as hosts. One mosquito pool containing non-blood-fed Cx. theileri and one blood-fed Culex pipiens pipiens (Cpp.) biotype pipiens were positive for WNV. A phylogram indicated that the obtained WNV sequences belonged to lineage 2, subclade 2 g. Several amino acid substitutions suspected as virulence markers were observed in the Iranian WNV strains. The three-dimensional structural homology model of the E-protein identified hot spot domains known to facilitate virus invasion and neurotropism. The recent detection of WNV lineage 2 in mosquitoes from several regions of Iran in consecutive years suggests that the virus is established in the country.
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