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Anderson NK, Preininger D, Fuxjager MJ. Comment on 'Parasite defensive limb movements enhance acoustic signal attraction in male little torrent frogs'. eLife 2023; 12:e89134. [PMID: 37812202 PMCID: PMC10561974 DOI: 10.7554/elife.89134] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 09/12/2023] [Indexed: 10/10/2023] Open
Abstract
Zhao et al. recently reported results which, they claim, suggest that sexual selection produces the multimodal displays seen in little torrent frogs (Amolops torrentis) by co-opting limb movements that originally evolved to support parasite defense (Zhao et al., 2022). Here, we explain why we believe this conclusion to be premature.
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Affiliation(s)
- Nigel K Anderson
- Department of Ecology, Evolution, and Organismal Biology, Brown UniversityProvidenceUnited States
| | - Doris Preininger
- Department of Evolutionary Biology, University of ViennaViennaAustria
- Vienna ZooViennaAustria
| | - Matthew J Fuxjager
- Department of Ecology, Evolution, and Organismal Biology, Brown UniversityProvidenceUnited States
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2
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Navarro Mamani DA, Ramos Huere H, Vera Buendia R, Rojas M, Chunga WA, Valdez Gutierrez E, Vergara Abarca W, Rivera Gerónimo H, Altamiranda-Saavedra M. Would Climate Change Influence the Potential Distribution and Ecological Niche of Bluetongue Virus and Its Main Vector in Peru? Viruses 2023; 15:v15040892. [PMID: 37112872 PMCID: PMC10145190 DOI: 10.3390/v15040892] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023] Open
Abstract
Bluetongue virus (BTV) is an arbovirus that is transmitted between domestic and wild ruminants by Culicoides spp. Its worldwide distribution depends on competent vectors and suitable environmental ecosystems that are becoming affected by climate change. Therefore, we evaluated whether climate change would influence the potential distribution and ecological niche of BTV and Culicoides insignis in Peru. Here, we analyzed BTV (n = 145) and C. insignis (n = 22) occurrence records under two shared socioeconomic pathway scenarios (SSP126 and SSP585) with five primary general circulation models (GCMs) using the kuenm R package v.1.1.9. Then, we obtained binary presence–absence maps and represented the risk of transmission of BTV and niche overlapping. The niche model approach showed that north and east Peru presented suitability in the current climate scenario and they would have a decreased risk of BTV, whilst its vector would be stable and expand with high agreement for the five GCMs. In addition, its niche overlap showed that the two niches almost overlap at present and would completely overlap with one another in future climate scenarios. These findings might be used to determine the areas of highest priority for entomological and virological investigations and surveillance in order to control and prevent bluetongue infections in Peru.
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Affiliation(s)
- Dennis A. Navarro Mamani
- Laboratorio de Microbiología y Parasitología—Sección Virología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru
- Correspondence:
| | - Heydi Ramos Huere
- Laboratorio de Microbiología y Parasitología—Sección Virología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru
| | - Renzo Vera Buendia
- Laboratorio de Microbiología y Parasitología—Sección Virología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru
| | - Miguel Rojas
- Laboratorio de Inmunología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru
| | - Wilfredo Arque Chunga
- Laboratorio de Referencia Nacional de Metaxenicas y Zoonosis Bacterianas, Centro Nacional de Salud Pública, Instituto Nacional de Salud, Lima 15001, Peru
| | - Edgar Valdez Gutierrez
- Laboratorio de Sanidad Animal “M.V. Atilio Pacheco Pacheco”, Escuela Profesional de Zootecnia, Universidad Nacional San Antonio Abad del Cusco, Cusco 08681, Peru
| | - Walter Vergara Abarca
- Laboratorio de Sanidad Animal “M.V. Atilio Pacheco Pacheco”, Escuela Profesional de Zootecnia, Universidad Nacional San Antonio Abad del Cusco, Cusco 08681, Peru
| | - Hermelinda Rivera Gerónimo
- Laboratorio de Microbiología y Parasitología—Sección Virología, Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima 15001, Peru
| | - Mariano Altamiranda-Saavedra
- Grupo de Investigación Bioforense, Tecnológico de Antioquia Institución Universitaria, Medellín 050005, Colombia
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Grimaud Y, Tran A, Benkimoun S, Boucher F, Esnault O, Cêtre-Sossah C, Cardinale E, Garros C, Guis H. Spatio-temporal modelling of Culicoides Latreille (Diptera: Ceratopogonidae) populations on Reunion Island (Indian Ocean). Parasit Vectors 2021; 14:288. [PMID: 34044880 PMCID: PMC8161615 DOI: 10.1186/s13071-021-04780-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 05/11/2021] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Reunion Island regularly faces outbreaks of bluetongue and epizootic hemorrhagic diseases, two insect-borne orbiviral diseases of ruminants. Hematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) are the vectors of bluetongue (BTV) and epizootic hemorrhagic disease (EHDV) viruses. In a previous study, statistical models based on environmental and meteorological data were developed for the five Culicoides species present in the island to provide a better understanding of their ecology and predict their presence and abundance. The purpose of this study was to couple these statistical models with a Geographic Information System (GIS) to produce dynamic maps of the distribution of Culicoides throughout the island. METHODS Based on meteorological data from ground weather stations and satellite-derived environmental data, the abundance of each of the five Culicoides species was estimated for the 2214 husbandry locations on the island for the period ranging from February 2016 to June 2018. A large-scale Culicoides sampling campaign including 100 farms was carried out in March 2018 to validate the model. RESULTS According to the model predictions, no husbandry location was free of Culicoides throughout the study period. The five Culicoides species were present on average in 57.0% of the husbandry locations for C. bolitinos Meiswinkel, 40.7% for C. enderleini Cornet & Brunhes, 26.5% for C. grahamii Austen, 87.1% for C. imicola Kieffer and 91.8% for C. kibatiensis Goetghebuer. The models also showed high seasonal variations in their distribution. During the validation process, predictions were acceptable for C. bolitinos, C. enderleini and C. kibatiensis, with normalized root mean square errors (NRMSE) of 15.4%, 13.6% and 16.5%, respectively. The NRMSE was 27.4% for C. grahamii. For C. imicola, the NRMSE was acceptable (11.9%) considering all husbandry locations except in two specific areas, the Cirque de Salazie-an inner mountainous part of the island-and the sea edge, where the model overestimated its abundance. CONCLUSIONS Our model provides, for the first time to our knowledge, an operational tool to better understand and predict the distribution of Culicoides in Reunion Island. As it predicts a wide spatial distribution of the five Culicoides species throughout the year and taking into consideration their vector competence, our results suggest that BTV and EHDV can circulate continuously on the island. As further actions, our model could be coupled with an epidemiological model of BTV and EHDV transmission to improve risk assessment of Culicoides-borne diseases on the island.
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Affiliation(s)
- Yannick Grimaud
- GDS Réunion, 1 rue du Père Hauck, 97418 La Plaine des Cafres, La Réunion, France
- University of Reunion Island, 15 avenue René Cassin, Sainte-Clotilde, 97715 La Réunion, France
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
| | - Annelise Tran
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
- CIRAD, UMR TETIS, Sainte-Clotilde, 97490 La Réunion, France
- TETIS, University of Montpellier, AgroParisTech, CIRAD, CNRS, INRAE, Montpellier, France
| | - Samuel Benkimoun
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
- CIRAD, UMR TETIS, Sainte-Clotilde, 97490 La Réunion, France
- TETIS, University of Montpellier, AgroParisTech, CIRAD, CNRS, INRAE, Montpellier, France
| | - Floriane Boucher
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
| | - Olivier Esnault
- GDS Réunion, 1 rue du Père Hauck, 97418 La Plaine des Cafres, La Réunion, France
| | - Catherine Cêtre-Sossah
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
| | - Eric Cardinale
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
| | - Claire Garros
- CIRAD, UMR ASTRE, Sainte-Clotilde, 97490 La Réunion, France
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
| | - Hélène Guis
- ASTRE, University of Montpellier, CIRAD, INRAE, Montpellier, France
- CIRAD, UMR ASTRE, 101 Antananarivo, Madagascar
- Institut Pasteur of Madagascar, Epidemiology and Clinical Research Unit, Antananarivo, Madagascar
- FOFIFA DRZVP, Antananarivo, Madagascar
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Möhlmann TWR, Keeling MJ, Wennergren U, Favia G, Santman-Berends I, Takken W, Koenraadt CJM, Brand SPC. Biting midge dynamics and bluetongue transmission: a multiscale model linking catch data with climate and disease outbreaks. Sci Rep 2021; 11:1892. [PMID: 33479304 PMCID: PMC7820592 DOI: 10.1038/s41598-021-81096-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 04/16/2020] [Indexed: 01/29/2023] Open
Abstract
Bluetongue virus (BTV) serotype 8 has been circulating in Europe since a major outbreak occurred in 2006, causing economic losses to livestock farms. The unpredictability of the biting activity of midges that transmit BTV implies difficulty in computing accurate transmission models. This study uniquely integrates field collections of midges at a range of European latitudes (in Sweden, The Netherlands, and Italy), with a multi-scale modelling approach. We inferred the environmental factors that influence the dynamics of midge catching, and then directly linked predicted midge catches to BTV transmission dynamics. Catch predictions were linked to the observed prevalence amongst sentinel cattle during the 2007 BTV outbreak in The Netherlands using a dynamic transmission model. We were able to directly infer a scaling parameter between daily midge catch predictions and the true biting rate per cow per day. Compared to biting rate per cow per day the scaling parameter was around 50% of 24 h midge catches with traps. Extending the estimated biting rate across Europe, for different seasons and years, indicated that whilst intensity of transmission is expected to vary widely from herd to herd, around 95% of naïve herds in western Europe have been at risk of sustained transmission over the last 15 years.
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Affiliation(s)
- Tim W R Möhlmann
- Laboratory of Entomology, Wageningen University and Research, P. O. Box 16, 1700 AA, Wageningen, The Netherlands
- IFM Theory and Modelling, Linköping University, 581 83, Linköping, Sweden
| | - Matt J Keeling
- School of Life Sciences, University of Warwick, Coventry, UK
- Zeeman Institute, University of Warwick, Coventry, UK
- Mathematics Institute, University of Warwick, Coventry, UK
| | - Uno Wennergren
- IFM Theory and Modelling, Linköping University, 581 83, Linköping, Sweden
| | - Guido Favia
- School of Biosciences and Veterinary Medicine, University of Camerino, 62032, Camerino, Italy
| | | | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, P. O. Box 16, 1700 AA, Wageningen, The Netherlands
| | - Constantianus J M Koenraadt
- Laboratory of Entomology, Wageningen University and Research, P. O. Box 16, 1700 AA, Wageningen, The Netherlands
| | - Samuel P C Brand
- School of Life Sciences, University of Warwick, Coventry, UK.
- Zeeman Institute, University of Warwick, Coventry, UK.
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5
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Clark NJ, Drovetski SV, Voelker G. Robust geographical determinants of infection prevalence and a contrasting latitudinal diversity gradient for haemosporidian parasites in Western Palearctic birds. Mol Ecol 2020; 29:3131-3143. [PMID: 32652721 DOI: 10.1111/mec.15545] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/01/2020] [Accepted: 07/06/2020] [Indexed: 12/16/2022]
Abstract
Identifying robust environmental predictors of infection probability is central to forecasting and mitigating the ongoing impacts of climate change on vector-borne disease threats. We applied phylogenetic hierarchical models to a data set of 2,171 Western Palearctic individual birds from 47 species to determine how climate and landscape variation influence infection probability for three genera of haemosporidian blood parasites (Haemoproteus, Leucocytozoon, and Plasmodium). Our comparative models found compelling evidence that birds in areas with higher vegetation density (captured by the normalized difference vegetation index [NDVI]) had higher likelihoods of carrying parasite infection. Magnitudes of this relationship were remarkably similar across parasite genera considering that these parasites use different arthropod vectors and are widely presumed to be epidemiologically distinct. However, we also uncovered key differences among genera that highlighted complexities in their climate responses. In particular, prevalences of Haemoproteus and Plasmodium showed strong but contrasting relationships with winter temperatures, supporting mounting evidence that winter warming is a key environmental filter impacting the dynamics of host-parasite interactions. Parasite phylogenetic community diversities demonstrated a clear but contrasting latitudinal gradient, with Haemoproteus diversity increasing towards the equator and Leucocytozoon diversity increasing towards the poles. Haemoproteus diversity also increased in regions with higher vegetation density, supporting our evidence that summer vegetation density is important for structuring the distributions of these parasites. Ongoing variation in winter temperatures and vegetation characteristics will probably have far-reaching consequences for the transmission and spread of vector-borne diseases.
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Affiliation(s)
- Nicholas J Clark
- UQ Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Sergei V Drovetski
- US Geological Survey, Patuxent Wildlife Research Center, Beltsville, MD, USA
| | - Gary Voelker
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, USA
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6
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Grimaud Y, Guis H, Chiroleu F, Boucher F, Tran A, Rakotoarivony I, Duhayon M, Cêtre-Sossah C, Esnault O, Cardinale E, Garros C. Modelling temporal dynamics of Culicoides Latreille (Diptera: Ceratopogonidae) populations on Reunion Island (Indian Ocean), vectors of viruses of veterinary importance. Parasit Vectors 2019; 12:562. [PMID: 31775850 PMCID: PMC6880491 DOI: 10.1186/s13071-019-3812-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/15/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) to ruminants. To date, five species of Culicoides are recorded in Reunion Island in which the first two are proven vector species: Culicoides bolitinos, C. imicola, C. enderleini, C. grahamii and C. kibatiensis. Meteorological and environmental factors can severely constrain Culicoides populations and activities and thereby affect dispersion and intensity of transmission of Culicoides-borne viruses. The aim of this study was to describe and predict the temporal dynamics of all Culicoides species present in Reunion Island. METHODS Between 2016 and 2018, 55 biweekly Culicoides catches using Onderstepoort Veterinary Institute traps were set up in 11 sites. A hurdle model (i.e. a presence/absence model combined with an abundance model) was developed for each species in order to determine meteorological and environmental drivers of presence and abundance of Culicoides. RESULTS Abundance displayed very strong heterogeneity between sites. Average Culicoides catch per site per night ranged from 4 to 45,875 individuals. Culicoides imicola was dominant at low altitude and C. kibatiensis at high altitude. A marked seasonality was observed for the three other species with annual variations. Twelve groups of variables were tested. It was found that presence and/or abundance of all five Culicoides species were driven by common parameters: rain, temperature, vegetation index, forested environment and host density. Other parameters such as wind speed and farm building opening size governed abundance level of some species. In addition, Culicoides populations were also affected by meteorological parameters and/or vegetation index with different lags of time, suggesting an impact on immature stages. Taking into account all the parameters for the final hurdle model, the error rate by Normalized Root mean Square Error ranged from 4.4 to 8.5%. CONCLUSIONS To our knowledge, this is the first study to model Culicoides population dynamics in Reunion Island. In the absence of vaccination and vector control strategies, determining periods of high abundance of Culicoides is a crucial first step towards identifying periods at high risk of transmission for the two economically important viruses they transmit.
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Affiliation(s)
- Yannick Grimaud
- GDS Réunion, 1 rue du Père Hauck, 97418 La Plaine des Cafres, La Réunion France
- University of Reunion Island, 15 avenue René Cassin, 97715 Sainte-Clotilde, La Réunion France
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
| | - Hélène Guis
- CIRAD, UMR ASTRE, 101 Antananarivo, Madagascar
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
- Epidemiology and clinical research unit, Institut Pasteur of Madagascar, Antananarivo, Madagascar
- FOFIFA DRZVP, Antananarivo, Madagascar
| | | | - Floriane Boucher
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
| | - Annelise Tran
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR TETIS, 97490 Sainte-Clotilde, La Réunion France
- TETIS, University of Montpellier, Montpellier, France
| | - Ignace Rakotoarivony
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, 34398 Montpellier, France
| | - Maxime Duhayon
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, 34398 Montpellier, France
| | - Catherine Cêtre-Sossah
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
| | - Olivier Esnault
- GDS Réunion, 1 rue du Père Hauck, 97418 La Plaine des Cafres, La Réunion France
| | - Eric Cardinale
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
| | - Claire Garros
- CIRAD, UMR ASTRE, 97490 Sainte-Clotilde, La Réunion France
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
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7
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Diarra M, Fall M, Fall AG, Diop A, Lancelot R, Seck MT, Rakotoarivony I, Allène X, Bouyer J, Guis H. Spatial distribution modelling of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in Senegal. Parasit Vectors 2018; 11:341. [PMID: 29884209 PMCID: PMC5994048 DOI: 10.1186/s13071-018-2920-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 05/27/2018] [Indexed: 12/04/2022] Open
Abstract
Background In Senegal, the last epidemic of African horse sickness (AHS) occurred in 2007. The western part of the country (the Niayes area) concentrates modern farms with exotic horses of high value and was highly affected during the 2007 outbreak that has started in the area. Several studies were initiated in the Niayes area in order to better characterize Culicoides diversity, ecology and the impact of environmental and climatic data on dynamics of proven and suspected vectors. The aims of this study are to better understand the spatial distribution and diversity of Culicoides in Senegal and to map their abundance throughout the country. Methods Culicoides data were obtained through a nationwide trapping campaign organized in 2012. Two successive collection nights were carried out in 96 sites in 12 (of 14) regions of Senegal at the end of the rainy season (between September and October) using OVI (Onderstepoort Veterinary Institute) light traps. Three different modeling approaches were compared: the first consists in a spatial interpolation by ordinary kriging of Culicoides abundance data. The two others consist in analyzing the relation between Culicoides abundance and environmental and climatic data to model abundance and investigate the environmental suitability; and were carried out by implementing generalized linear models and random forest models. Results A total of 1,373,929 specimens of the genus Culicoides belonging to at least 32 different species were collected in 96 sites during the survey. According to the RF (random forest) models which provided better estimates of abundances than Generalized Linear Models (GLM) models, environmental and climatic variables that influence species abundance were identified. Culicoides imicola, C. enderleini and C. miombo were mostly driven by average rainfall and minimum and maximum normalized difference vegetation index. Abundance of C. oxystoma was mostly determined by average rainfall and day temperature. Culicoides bolitinos had a particular trend; the environmental and climatic variables above had a lesser impact on its abundance. RF model prediction maps for the first four species showed high abundance in southern Senegal and in the groundnut basin area, whereas C. bolitinos was present in southern Senegal, but in much lower abundance. Conclusions Environmental and climatic variables of importance that influence the spatial distribution of species abundance were identified. It is now crucial to evaluate the vector competence of major species and then combine the vector densities with densities of horses to quantify the risk of transmission of AHS virus across the country. Electronic supplementary material The online version of this article (10.1186/s13071-018-2920-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maryam Diarra
- InstitutSénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal. .,Université Gaston Berger, Laboratoire d'Etudes et de Recherches en Statistiques et Développement, Saint-Louis, Sénégal. .,Institut Pasteur de Dakar, G4 Biostatistique, Bioinformatique et Modélisation, Dakar, Sénégal.
| | - Moussa Fall
- InstitutSénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Assane Gueye Fall
- InstitutSénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Aliou Diop
- Université Gaston Berger, Laboratoire d'Etudes et de Recherches en Statistiques et Développement, Saint-Louis, Sénégal
| | - Renaud Lancelot
- CIRAD, ASTRE, Montpellier, France.,ASTRE, INRA, CIRAD, Univ Montpellier, Montpellier, France
| | - Momar Talla Seck
- InstitutSénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Ignace Rakotoarivony
- CIRAD, ASTRE, Montpellier, France.,ASTRE, INRA, CIRAD, Univ Montpellier, Montpellier, France
| | - Xavier Allène
- CIRAD, ASTRE, Montpellier, France.,ASTRE, INRA, CIRAD, Univ Montpellier, Montpellier, France
| | - Jérémy Bouyer
- InstitutSénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal.,CIRAD, ASTRE, Montpellier, France.,ASTRE, INRA, CIRAD, Univ Montpellier, Montpellier, France
| | - Hélène Guis
- CIRAD, ASTRE, Montpellier, France.,ASTRE, INRA, CIRAD, Univ Montpellier, Montpellier, France.,Cirad, ASTRE, Antananarivo, Madagascar.,Institut Pasteur, Epidemiology Unit, Antananarivo, Madagascar.,FOFIFA, DRZVP, Antananarivo, Madagascar
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8
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Jess S, Thompson GM, Clawson S, Forsythe IWN, Rea I, Gordon AW, Murchie AK. Surveillance of biting midges (Culicoides spp.) in Northern Ireland: influence of seasonality, surrounding habitat and livestock housing. MEDICAL AND VETERINARY ENTOMOLOGY 2018; 32:48-60. [PMID: 28842922 DOI: 10.1111/mve.12258] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/30/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
Biting midges, Culicoides spp. (Diptera: Ceratopogonidae), are important vectors of viral pathogens. Following the outbreak of bluetongue serotype 8 in Europe between 2006 and 2009, many Culicoides surveillance programmes were initiated to identify vector-active periods, in accordance with European Commission regulation 2007/1266/EC. This study utilized surveillance data from 4 years of continuous light-trapping at 14 sites in Northern Ireland. The number of captured Culicoides varied from none during the vector-free period (December-April) to more than 36 000 per night during peak activity in the summer. The Obsoletus group represented 75% of Culicoides collected and the Pulicaris group represented 21%. A total of 91% of Culicoides were female, of which 42% were parous. Abundance data, sex ratios and parous rates suggested that both the Obsoletus and Pulicaris groups underwent three generations/year. The Obsoletus group was associated with cattle-rearing habitats and woodland, the Impunctatus group was found in habitats related to sheep rearing and the Pulicaris group were associated with both cattle and sheep. Housing did not reduce incursion of female Obsoletus group Culicoides but it did for males and for the Pulicaris group Culicoides. The influence of housing was strongly affected by time of year, probably reflecting the presence of livestock indoors/outdoors.
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Affiliation(s)
- S Jess
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - G M Thompson
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
- School of Biological Sciences, Queen's University of Belfast, Belfast, Northern Ireland
| | - S Clawson
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - I W N Forsythe
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - I Rea
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - A W Gordon
- Finance and Corporate Affairs Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
| | - A K Murchie
- Sustainable Agri-Food Sciences Division, Agri-Food and Biosciences Institute, Belfast, Northern Ireland
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9
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Brand SPC, Keeling MJ. The impact of temperature changes on vector-borne disease transmission: Culicoides midges and bluetongue virus. J R Soc Interface 2017; 14:rsif.2016.0481. [PMID: 28298609 DOI: 10.1098/rsif.2016.0481] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 02/20/2017] [Indexed: 11/12/2022] Open
Abstract
It is a long recognized fact that climatic variations, especially temperature, affect the life history of biting insects. This is particularly important when considering vector-borne diseases, especially in temperate regions where climatic fluctuations are large. In general, it has been found that most biological processes occur at a faster rate at higher temperatures, although not all processes change in the same manner. This differential response to temperature, often considered as a trade-off between onward transmission and vector life expectancy, leads to the total transmission potential of an infected vector being maximized at intermediate temperatures. Here we go beyond the concept of a static optimal temperature, and mathematically model how realistic temperature variation impacts transmission dynamics. We use bluetongue virus (BTV), under UK temperatures and transmitted by Culicoides midges, as a well-studied example where temperature fluctuations play a major role. We first consider an optimal temperature profile that maximizes transmission, and show that this is characterized by a warm day to maximize biting followed by cooler weather to maximize vector life expectancy. This understanding can then be related to recorded representative temperature patterns for England, the UK region which has experienced BTV cases, allowing us to infer historical transmissibility of BTV, as well as using forecasts of climate change to predict future transmissibility. Our results show that when BTV first invaded northern Europe in 2006 the cumulative transmission intensity was higher than any point in the last 50 years, although with climate change such high risks are the expected norm by 2050. Such predictions would indicate that regular BTV epizootics should be expected in the UK in the future.
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Affiliation(s)
- Samuel P C Brand
- Zeeman Institute: SBIDER, University of Warwick, Coventry CV4 7AL, UK .,School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Matt J Keeling
- Zeeman Institute: SBIDER, University of Warwick, Coventry CV4 7AL, UK.,School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.,Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK
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10
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Abstract
The performance of different bluetongue control measures related to both vaccination and protection from bluetongue virus (BTV) vectors was assessed. By means of a mathematical model, it was concluded that when vaccination is applied on 95% of animals even for 3 years, bluetongue cannot be eradicated and is able to re‐emerge. Only after 5 years of vaccination, the infection may be close to the eradication levels. In the absence of vaccination, the disease can persist for several years, reaching an endemic condition with low level of prevalence of infection. Among the mechanisms for bluetongue persistence, the persistence in the wildlife, the transplacental transmission in the host, the duration of viraemia and the possible vertical transmission in vectors were assessed. The criteria of the current surveillance scheme in place in the EU for demonstration of the virus absence need revision, because it was highlighted that under the current surveillance policy bluetongue circulation might occur undetected. For the safe movement of animals, newborn ruminants from vaccinated mothers with neutralising antibodies can be considered protected against infection, although a protective titre threshold cannot be identified. The presence of colostral antibodies interferes with the vaccine immunisation in the newborn for more than 3 months after birth, whereas the minimum time after vaccination of animal to be considered immune can be up to 48 days. The knowledge about vectors ecology, mechanisms of over‐wintering and criteria for the seasonally vector‐free period was updated. Some Culicoides species are active throughout the year and an absolute vector‐free period may not exist at least in some areas in Europe. To date, there is no evidence that the use of insecticides and repellents reduce the transmission of BTV in the field, although this may reduce host/vector contact. By only using pour‐on insecticides, protection of animals is lower than the one provided by vector‐proof establishments. This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2017.EN-1182/full, http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2017.EN-1171/full
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11
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Özkan Ş, Vitali A, Lacetera N, Amon B, Bannink A, Bartley DJ, Blanco-Penedo I, de Haas Y, Dufrasne I, Elliott J, Eory V, Fox NJ, Garnsworthy PC, Gengler N, Hammami H, Kyriazakis I, Leclère D, Lessire F, Macleod M, Robinson TP, Ruete A, Sandars DL, Shrestha S, Stott AW, Twardy S, Vanrobays ML, Ahmadi BV, Weindl I, Wheelhouse N, Williams AG, Williams HW, Wilson AJ, Østergaard S, Kipling RP. Challenges and priorities for modelling livestock health and pathogens in the context of climate change. ENVIRONMENTAL RESEARCH 2016; 151:130-144. [PMID: 27475053 DOI: 10.1016/j.envres.2016.07.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 07/21/2016] [Accepted: 07/22/2016] [Indexed: 06/06/2023]
Abstract
Climate change has the potential to impair livestock health, with consequences for animal welfare, productivity, greenhouse gas emissions, and human livelihoods and health. Modelling has an important role in assessing the impacts of climate change on livestock systems and the efficacy of potential adaptation strategies, to support decision making for more efficient, resilient and sustainable production. However, a coherent set of challenges and research priorities for modelling livestock health and pathogens under climate change has not previously been available. To identify such challenges and priorities, researchers from across Europe were engaged in a horizon-scanning study, involving workshop and questionnaire based exercises and focussed literature reviews. Eighteen key challenges were identified and grouped into six categories based on subject-specific and capacity building requirements. Across a number of challenges, the need for inventories relating model types to different applications (e.g. the pathogen species, region, scale of focus and purpose to which they can be applied) was identified, in order to identify gaps in capability in relation to the impacts of climate change on animal health. The need for collaboration and learning across disciplines was highlighted in several challenges, e.g. to better understand and model complex ecological interactions between pathogens, vectors, wildlife hosts and livestock in the context of climate change. Collaboration between socio-economic and biophysical disciplines was seen as important for better engagement with stakeholders and for improved modelling of the costs and benefits of poor livestock health. The need for more comprehensive validation of empirical relationships, for harmonising terminology and measurements, and for building capacity for under-researched nations, systems and health problems indicated the importance of joined up approaches across nations. The challenges and priorities identified can help focus the development of modelling capacity and future research structures in this vital field. Well-funded networks capable of managing the long-term development of shared resources are required in order to create a cohesive modelling community equipped to tackle the complex challenges of climate change.
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Affiliation(s)
- Şeyda Özkan
- Department of Animal and Aquacultural Sciences, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences (NMBU), Post Box 5003, Ås 1430, Norway
| | - Andrea Vitali
- University of Tuscia, Department of Agriculture and Forestry Science (DAFNE), Via San Camillo De Lellis, snc, Viterbo 01100, Italy
| | - Nicola Lacetera
- University of Tuscia, Department of Agriculture and Forestry Science (DAFNE), Via San Camillo De Lellis, snc, Viterbo 01100, Italy
| | - Barbara Amon
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Max-Eyth-Allee 100, Potsdam 14469, Germany
| | - André Bannink
- Wageningen UR Livestock Research, P.O. Box 338, Wageningen 6700 AH, The Netherlands
| | - Dave J Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Isabel Blanco-Penedo
- Animal Welfare Subprogram, IRTA, Veinat de Sies s/n, Monells, Girona 17121, Spain
| | - Yvette de Haas
- Wageningen UR Livestock Research, P.O. Box 338, Wageningen 6700 AH, The Netherlands
| | - Isabelle Dufrasne
- Nutrition Unit, Animal Production Department, Veterinary Faculty, University of Liège, Boulevard de Colonster 20, Bât. B43, Liège 4000, Belgium
| | - John Elliott
- ADAS UK Ltd, 4205 Park Approach, Thorpe Park, Leeds LS15 8GB, UK
| | - Vera Eory
- Scotland's Rural College (SRUC), Peter Wilson Building, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, UK
| | - Naomi J Fox
- Scotland's Rural College (SRUC), Animal and Veterinary Sciences, Roslin Institute Building, Easter Bush, Midlothian EH25 9RG, UK
| | - Phil C Garnsworthy
- University of Nottingham, School of Biosciences, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Nicolas Gengler
- Agriculture, Bio-engineering and Chemistry Department, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés, 2, Gembloux B-5030, Belgium
| | - Hedi Hammami
- Agriculture, Bio-engineering and Chemistry Department, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés, 2, Gembloux B-5030, Belgium
| | - Ilias Kyriazakis
- School of Agriculture, Food and Rural Development, Newcastle University, King's Road, Newcastle upon Tyne NE1 7RU, UK
| | - David Leclère
- Ecosystems Services and Management program (ESM), International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, Laxenburg A-2361, Austria
| | - Françoise Lessire
- Nutrition Unit, Animal Production Department, Veterinary Faculty, University of Liège, Boulevard de Colonster 20, Bât. B43, Liège 4000, Belgium
| | - Michael Macleod
- Scotland's Rural College (SRUC), Peter Wilson Building, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, UK
| | - Timothy P Robinson
- Livestock Systems and Environment, International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Alejandro Ruete
- Department of Ecology, Swedish University of Agricultural Sciences, Ullsvägen 16, Uppsala 75007, Sweden
| | - Daniel L Sandars
- School of Energy, Environment and Agrifood, Cranfield University, Bedford MK43 0AL, UK
| | - Shailesh Shrestha
- Scotland's Rural College (SRUC), Peter Wilson Building, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, UK
| | - Alistair W Stott
- Scotland's Rural College (SRUC), Peter Wilson Building, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, UK
| | - Stanislaw Twardy
- Institute of Technology and Life Sciences at Falenty (P122) Malopolska Research Centre in Krakow, ul. Ulanow 21B, 31-450 Krakow, Poland
| | - Marie-Laure Vanrobays
- Agriculture, Bio-engineering and Chemistry Department, Gembloux Agro-Bio Tech, University of Liège, Passage des Déportés, 2, Gembloux B-5030, Belgium
| | - Bouda Vosough Ahmadi
- Scotland's Rural College (SRUC), Peter Wilson Building, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, UK
| | - Isabelle Weindl
- Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB), Max-Eyth-Allee 100, Potsdam 14469, Germany; Potsdam Institute for Climate Impact Research (PIK), PO Box 60 12 03, 14412 Potsdam, Germany
| | - Nick Wheelhouse
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Adrian G Williams
- School of Energy, Environment and Agrifood, Cranfield University, Bedford MK43 0AL, UK
| | - Hefin W Williams
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, 1st Floor, Stapledon Building, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EE, UK
| | | | - Søren Østergaard
- Department of Animal Science, Aarhus University, Tjele 8830, Denmark
| | - Richard P Kipling
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, 1st Floor, Stapledon Building, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EE, UK.
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12
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Robin M, Page P, Archer D, Baylis M. African horse sickness: The potential for an outbreak in disease-free regions and current disease control and elimination techniques. Equine Vet J 2016; 48:659-69. [PMID: 27292229 DOI: 10.1111/evj.12600] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 06/09/2016] [Indexed: 11/26/2022]
Abstract
African horse sickness (AHS) is an arboviral disease of equids transmitted by Culicoides biting midges. The virus is endemic in parts of sub-Saharan Africa and official AHS disease-free status can be obtained from the World Organization for Animal Health on fulfilment of a number of criteria. AHS is associated with case fatality rates of up to 95%, making an outbreak among naïve horses both a welfare and economic disaster. The worldwide distributions of similar vector-borne diseases (particularly bluetongue disease of ruminants) are changing rapidly, probably due to a combination of globalisation and climate change. There is extensive evidence that the requisite conditions for an AHS epizootic currently exist in disease-free countries. In particular, although the stringent regulations enforced upon competition horses make them extremely unlikely to redistribute the virus, there are great concerns over the effects of illegal equid movement. An outbreak of AHS in a disease free region would have catastrophic effects on equine welfare and industry, particularly for international events such as the Olympic Games. While many regions have contingency plans in place to manage an outbreak of AHS, further research is urgently required if the equine industry is to avoid or effectively contain an AHS epizootic in disease-free regions. This review describes the key aspects of AHS as a global issue and discusses the evidence supporting concerns that an epizootic may occur in AHS free countries, the planned government responses, and the roles and responsibilities of equine veterinarians.
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Affiliation(s)
- M Robin
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - P Page
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - D Archer
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - M Baylis
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, UK
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13
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Kluiters G, Pagès N, Carpenter S, Gardès L, Guis H, Baylis M, Garros C. Morphometric discrimination of two sympatric sibling species in the Palaearctic region, Culicoides obsoletus Meigen and C. scoticus Downes & Kettle (Diptera: Ceratopogonidae), vectors of bluetongue and Schmallenberg viruses. Parasit Vectors 2016; 9:262. [PMID: 27146157 PMCID: PMC4857416 DOI: 10.1186/s13071-016-1520-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 04/20/2016] [Indexed: 11/10/2022] Open
Abstract
Background Some Palaearctic biting midge species (subgenus Avaritia) have been implicated as vectors of bluetongue virus in northern Europe. Separation of two species (C. obsoletus and C. scoticus) is considered difficult morphologically and, often, these female specimens are grouped in entomological studies. However, species-specific identification is desirable to understand their life history characteristics, assess their roles in disease transmission or measure their abundance during arboviral outbreaks. This study aims to investigate whether morphometric identification techniques can be applied to female C. obsoletus and C. scoticus individuals trapped at different geographical regions and time periods during the vector season. Methods C. obsoletus and C. scoticus were collected using light-suction traps from the UK, France and Spain, with two geographical locations sampled per country. A total of 759 C. obsoletus/C. scoticus individuals were identified using a molecular assay based on the cytochrome c oxidase subunit I gene. Fifteen morphometric measurements were taken from the head, wings and abdomen of slide-mounted specimens, and ratios calculated between these measurements. Multivariate analyses explored whether a combination of morphometric variables could lead to accurate species identification. Finally, Culicoides spp. collected in France at the start, middle and end of the adult vector season were compared, to determine whether seasonal variation exists in any of the morphometric measurements. Results The principal component analyses revealed that abdominal characteristics: length and width of the smaller and larger spermathecae, and the length of the chitinous plates and width between them, are the most reliable morphometric characteristics to differentiate between the species. Seasonal variation in the size of each species was observed for head and wing measurements, but not abdominal measurements. Geographical variation in the size of Culicoides spp. was also observed and is likely to be related to temperature at the trapping sites, with smaller individuals trapped at more southern latitudes. Conclusions Our results suggest that female C. obsoletus and C. scoticus individuals can be separated under a stereomicroscope using abdominal measurements. Although we show the length and width of the spermathecae can be used to differentiate between the species, this can be time-consuming, so we recommend undertaking this using standardized subsampling of catches. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1520-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- G Kluiters
- Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group, Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TE, UK.
| | - N Pagès
- Centre de Recerca en Sanitat 26 Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona, Spain.,Present address: CIRAD, UMR CMAEE, F-97170, Petit-Bourg, Guadeloupe, France
| | - S Carpenter
- Vector-borne Viral Disease Programme, The Pirbright Institute, Woking, GU24 0NF, UK
| | - L Gardès
- Cirad, UMR15 CMAEE, F-34398, Montpellier, France.,INRA, UMR1309 CMAEE, F-34398, Montpellier, France
| | - H Guis
- Cirad, UMR15 CMAEE, F-34398, Montpellier, France.,INRA, UMR1309 CMAEE, F-34398, Montpellier, France
| | - M Baylis
- Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group, Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Neston, Cheshire, CH64 7TE, UK.,National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
| | - C Garros
- Cirad, UMR15 CMAEE, F-34398, Montpellier, France.,INRA, UMR1309 CMAEE, F-34398, Montpellier, France
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14
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Napp S, Allepuz A, Purse BV, Casal J, García-Bocanegra I, Burgin LE, Searle KR. Understanding Spatio-Temporal Variability in the Reproduction Ratio of the Bluetongue (BTV-1) Epidemic in Southern Spain (Andalusia) in 2007 Using Epidemic Trees. PLoS One 2016; 11:e0151151. [PMID: 26963397 PMCID: PMC4786328 DOI: 10.1371/journal.pone.0151151] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/23/2016] [Indexed: 11/21/2022] Open
Abstract
Andalusia (Southern Spain) is considered one of the main routes of introduction of bluetongue virus (BTV) into Europe, evidenced by a devastating epidemic caused by BTV-1 in 2007. Understanding the pattern and the drivers of BTV-1 spread in Andalusia is critical for effective detection and control of future epidemics. A long-standing metric for quantifying the behaviour of infectious diseases is the case-reproduction ratio (Rt), defined as the average number of secondary cases arising from a single infected case at time t (for t>0). Here we apply a method using epidemic trees to estimate the between-herd case reproduction ratio directly from epidemic data allowing the spatial and temporal variability in transmission to be described. We then relate this variability to predictors describing the hosts, vectors and the environment to better understand why the epidemic spread more quickly in some regions or periods. The Rt value for the BTV-1 epidemic in Andalusia peaked in July at 4.6, at the start of the epidemic, then decreased to 2.2 by August, dropped below 1 by September (0.8), and by October it had decreased to 0.02. BTV spread was the consequence of both local transmission within established disease foci and BTV expansion to distant new areas (i.e. new foci), which resulted in a high variability in BTV transmission, not only among different areas, but particularly through time, which suggests that general control measures applied at broad spatial scales are unlikely to be effective. This high variability through time was probably due to the impact of temperature on BTV transmission, as evidenced by a reduction in the value of Rt by 0.0041 for every unit increase (day) in the extrinsic incubation period (EIP), which is itself directly dependent on temperature. Moreover, within the range of values at which BTV-1 transmission occurred in Andalusia (20.6°C to 29.5°C) there was a positive correlation between temperature and Rt values, although the relationship was not linear, probably as a result of the complex relationship between temperature and the different parameters affecting BTV transmission. Rt values for BTV-1 in Andalusia fell below the threshold of 1 when temperatures dropped below 21°C, a much higher threshold than that reported in other BTV outbreaks, such as the BTV-8 epidemic in Northern Europe. This divergence may be explained by differences in the adaptation to temperature of the main vectors of the BTV-1 epidemic in Andalusia (Culicoides imicola) compared those of the BTV-8 epidemic in Northern Europe (Culicoides obsoletus). Importantly, we found that BTV transmission (Rt value) increased significantly in areas with higher densities of sheep. Our analysis also established that control of BTV-1 in Andalusia was complicated by the simultaneous establishment of several distant foci at the start of the epidemic, which may have been caused by several independent introductions of infected vectors from the North of Africa. We discuss the implications of these findings for BTV surveillance and control in this region of Europe.
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Affiliation(s)
- S. Napp
- Centre de Recerca en Sanitat Animal (CReSA)—Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- * E-mail:
| | - A. Allepuz
- Centre de Recerca en Sanitat Animal (CReSA)—Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain
| | - B. V. Purse
- Centre for Ecology and Hydrology, MacLean Bldg, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB, United Kingdom
| | - J. Casal
- Centre de Recerca en Sanitat Animal (CReSA)—Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Barcelona, Spain
| | - I. García-Bocanegra
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de Córdoba (UCO), Campus Universitario de Rabanales, 14071 Córdoba, Spain
| | - L. E. Burgin
- Met Office, FitzRoy Road, Exeter, Devon EX1 3PB United Kingdom
| | - K. R. Searle
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, United Kingdom
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15
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Diarra M, Fall M, Lancelot R, Diop A, Fall AG, Dicko A, Seck MT, Garros C, Allène X, Rakotoarivony I, Bakhoum MT, Bouyer J, Guis H. Modelling the Abundances of Two Major Culicoides (Diptera: Ceratopogonidae) Species in the Niayes Area of Senegal. PLoS One 2015; 10:e0131021. [PMID: 26121048 PMCID: PMC4487250 DOI: 10.1371/journal.pone.0131021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/26/2015] [Indexed: 11/19/2022] Open
Abstract
In Senegal, considerable mortality in the equine population and hence major economic losses were caused by the African horse sickness (AHS) epizootic in 2007. Culicoides oxystoma and Culicoides imicola, known or suspected of being vectors of bluetongue and AHS viruses are two predominant species in the vicinity of horses and are present all year-round in Niayes area, Senegal. The aim of this study was to better understand the environmental and climatic drivers of the dynamics of these two species. Culicoides collections were obtained using OVI (Onderstepoort Veterinary Institute) light traps at each of the 5 sites for three nights of consecutive collection per month over one year. Cross Correlation Map analysis was performed to determine the time-lags for which environmental variables and abundance data were the most correlated. C. oxystoma and C. imicola count data were highly variable and overdispersed. Despite modelling large Culicoides counts (over 220,000 Culicoides captured in 354 night-traps), using on-site climate measures, overdispersion persisted in Poisson, negative binomial, Poisson regression mixed-effect with random effect at the site of capture models. The only model able to take into account overdispersion was the Poisson regression mixed-effect model with nested random effects at the site and date of capture levels. According to this model, meteorological variables that contribute to explaining the dynamics of C. oxystoma and C. imicola abundances were: mean temperature and relative humidity of the capture day, mean humidity between 21 and 19 days prior a capture event, density of ruminants, percentage cover of water bodies within a 2 km radius and interaction between temperature and humidity for C. oxystoma; mean rainfall and NDVI of the capture day and percentage cover of water bodies for C. imicola. Other variables such as soil moisture, wind speed, degree days, land cover or landscape metrics could be tested to improve the models. Further work should also assess whether other trapping methods such as host-baited traps help reduce overdispersion.
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Affiliation(s)
- Maryam Diarra
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
- Université Gaston Berger, Laboratoire d’Etudes et de Recherches en Statistiques et Développement, Saint-Louis, Sénégal
- * E-mail:
| | - Moussa Fall
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Renaud Lancelot
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Aliou Diop
- Université Gaston Berger, Laboratoire d’Etudes et de Recherches en Statistiques et Développement, Saint-Louis, Sénégal
| | - Assane G. Fall
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Ahmadou Dicko
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Momar Talla Seck
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Claire Garros
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Xavier Allène
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Ignace Rakotoarivony
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Mame Thierno Bakhoum
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
| | - Jérémy Bouyer
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires, Dakar, Sénégal
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Hélène Guis
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France
- INRA, UMR1309 CMAEE, F-34398 Montpellier, France
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Hope A, Gubbins S, Sanders C, Denison E, Barber J, Stubbins F, Baylis M, Carpenter S. A comparison of commercial light-emitting diode baited suction traps for surveillance of Culicoides in northern Europe. Parasit Vectors 2015; 8:239. [PMID: 25896343 PMCID: PMC4415440 DOI: 10.1186/s13071-015-0846-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 04/08/2015] [Indexed: 11/13/2022] Open
Abstract
Background The response of Culicoides biting midges (Diptera: Ceratopogonidae) to artificial light sources has led to the use of light-suction traps in surveillance programmes. Recent integration of light emitting diodes (LED) in traps improves flexibility in trapping through reduced power requirements and also allows the wavelength of light used for trapping to be customized. This study investigates the responses of Culicoides to LED light-suction traps emitting different wavelengths of light to make recommendations for use in surveillance. Methods The abundance and diversity of Culicoides collected using commercially available traps fitted with Light Emitting Diode (LED) platforms emitting ultraviolet (UV) (390 nm wavelength), blue (430 nm), green (570 nm), yellow (590 nm), red (660 nm) or white light (425 nm – 750 nm with peaks at 450 nm and 580 nm) were compared. A Centre for Disease Control (CDC) UV light-suction trap was also included within the experimental design which was fitted with a 4 watt UV tube (320-420 nm). Generalised linear models with negative binomial error structure and log-link function were used to compare trap abundance according to LED colour, meteorological conditions and seasonality. Results The experiment was conducted over 49 nights with 42,766 Culicoides caught in 329 collections. Culicoides obsoletus Meigen and Culicoides scoticus Downes and Kettle responded indiscriminately to all wavelengths of LED used with the exception of red which was significantly less attractive. In contrast, Culicoides dewulfi Goetghebuer and Culicoides pulicaris Linnaeus were found in significantly greater numbers in the green LED trap than in the UV LED trap. The LED traps collected significantly fewer Culicoides than the standard CDC UV light-suction trap. Conclusions Catches of Culicoides were reduced in LED traps when compared to the standard CDC UV trap, however, their reduced power requirement and small size fulfils a requirement for trapping in logistically challenging areas or where many traps are deployed at a single site. Future work should combine light wavelengths to improve trapping sensitivity and potentially enable direct comparisons with collections from hosts, although this may ultimately require different forms of baits to be developed. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0846-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrew Hope
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - Simon Gubbins
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - Christopher Sanders
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - Eric Denison
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - James Barber
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - Francesca Stubbins
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
| | - Matthew Baylis
- Liverpool University Climate and Infectious Diseases of Animals (Lucinda) Group, University of Liverpool, Neston, Cheshire, United Kingdom. .,Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, United Kingdom.
| | - Simon Carpenter
- Vector-borne Viral Disease Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
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Kluiters G, Swales H, Baylis M. Local dispersal of palaearctic Culicoides biting midges estimated by mark-release-recapture. Parasit Vectors 2015; 8:86. [PMID: 25886488 PMCID: PMC4327803 DOI: 10.1186/s13071-015-0658-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/12/2015] [Indexed: 11/24/2022] Open
Abstract
Background Farm to farm movement of Culicoides midges is believed to play a critical role in the spread of bluetongue (BT), Schmallenberg and other midge-borne diseases. To help understand and predict the spread of diseases carried by midges, there is a need to determine their dispersal patterns, and to identify factors contributing to the direction taken and distance travelled. Methods The dispersal of Obsoletus Group members was studied on 19 farms around Bala, north Wales. Field-collected Culicoides were trapped in a black-light (OVI) trap and self-marked in the collecting vessel, using micronized fluorescent dust. Culicoides were released at a central farm and OVI traps set on 18 surrounding farms, at distances of 1 to 4 km. The study was repeated using six colours of fluorescent dust over an 18 day period. Results An estimated 61,062 (95% CI = 56,298-65,830) marked Culicoides were released during the study and 12 (0.02%) Culicoides were recaptured. Of the females recaptured, six were C. obsoletus/scoticus, two C. dewulfi, two C. pulicaris and one C. festivipennis. The male was C. obsoletus. Recaptures occurred 1–2.5 km from the release site, with greatest numbers at 2.5 km. Most recaptures were 2 nights post-release; none were more than 3 nights post-release. Two females were recovered at 1.5 km on the night of release and one male at 1 km two nights post-release. The mean distance travelled (MDT) for males was 1 km, females was 2.21 km, and all recaptured Culicoides was 2.15 km. Recaptures were made both downwind and upwind of the prevailing wind direction during the trapping periods, highlighting possible passive and active dispersal of Culicoides between farms. Conclusions This is the first study to demonstrate farm to farm movement of the main Palaearctic BT vector species, the Obsoletus Group. Such movement has disease control implications in terms of the vectoral movement of disease between farms. The results suggest that Culicoides control measures applied at an infected farm (trapping or killing Culicoides) will reduce risk of spread to neighbouring farms by lessening the number of Culicoides dispersing from that farm, as well as reducing transmission at the source farm itself.
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Affiliation(s)
- Georgette Kluiters
- Institute of Infection and Global Health, Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group, University of Liverpool, Leahurst Campus, Neston, Cheshire, UK.
| | - Harry Swales
- Institute of Infection and Global Health, Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group, University of Liverpool, Leahurst Campus, Neston, Cheshire, UK.
| | - Matthew Baylis
- Institute of Infection and Global Health, Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group, University of Liverpool, Leahurst Campus, Neston, Cheshire, UK. .,National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Neston, UK.
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18
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Validation of fluorescent dust marking of Culicoides biting midges and the design of a self-marking technique. Parasit Vectors 2015; 8:54. [PMID: 25623268 PMCID: PMC4322483 DOI: 10.1186/s13071-015-0657-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/12/2015] [Indexed: 11/21/2022] Open
Abstract
Background Investigation of insect flight patterns frequently involves the use of dispersal studies. A common method for studying insect dispersal is mark-release-recapture (MRR) techniques using wild-caught insects in their natural environment; however, this requires a suitable marker. At present, no studies have been performed to identify markers that are suitable for use in midges within the Obsoletus Group, and visible by eye or down a light microscope. Methods A series of 11 experiments were undertaken to determine the effectiveness of three colours of Brilliant General Purpose (BGP) fluorescent dusts in marking Culicoides midges. Three areas were focused on: 1) dust properties, 2) the effect on Culicoides, and 3) dust application in the field. Results All three dusts were insoluble in water, 10% washing-up liquid and 70% ethanol. They were visible down a microscope, with and without the use of a black light, and two were highly visible without the need for a microscope. The dusts remained adherent to the marked Culicoides for the duration of the experiments, did not transfer between marked and unmarked individuals or the environment, and remained adherent when the Culicoides were stored in an ethanol or water-based solution. The dusts had no effect on the mortality rate of the insects over the 48 hrs of the experiment. There were no significant differences between the recorded behaviours undertaken by undusted control Culicoides and the BGP fluorescent dusted Culicoides. Field-based marking of Culicoides can be achieved using a ‘self-marking’ technique, whereby the trapping vessel is pre-dusted with fluorescent dust prior to trapping the individuals to be marked. Conclusions This is the first study to identify BGP fluorescent dusts as markers for use with Obsoletus Group Culicoides. BGP fluorescent dusts provide a quick and effective method of marking and identifying Culicoides for both field and laboratory studies. The self-marking technique minimises the time needed to handle specimens prior to release.
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Environmental drivers of Culicoides phenology: how important is species-specific variation when determining disease policy? PLoS One 2014; 9:e111876. [PMID: 25386940 PMCID: PMC4227682 DOI: 10.1371/journal.pone.0111876] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/18/2014] [Indexed: 11/19/2022] Open
Abstract
Since 2006, arboviruses transmitted by Culicoides biting midges (Diptera: Ceratopogonidae) have caused significant disruption to ruminant production in northern Europe. The most serious incursions involved strains of bluetongue virus (BTV), which cause bluetongue (BT) disease. To control spread of BTV, movement of susceptible livestock is restricted with economic and animal welfare impacts. The timing of BTV transmission in temperate regions is partly determined by the seasonal presence of adult Culicoides females. Legislative measures therefore allow for the relaxation of ruminant movement restrictions during winter, when nightly light-suction trap catches of Culicoides fall below a threshold (the ‘seasonally vector free period’: SVFP). We analysed five years of time-series surveillance data from light-suction trapping in the UK to investigate whether significant inter-specific and yearly variation in adult phenology exists, and whether the SVFP is predictable from environmental factors. Because female vector Culicoides are not easily morphologically separated, inter-specific comparisons in phenology were drawn from male populations. We demonstrate significant inter-specific differences in Culicoides adult phenology with the season of Culicoides scoticus approximately eight weeks shorter than Culicoides obsoletus. Species-specific differences in the length of the SVFP were related to host density and local variation in landscape habitat. When the Avaritia Culicoides females were modelled as a group (as utilised in the SFVP), we were unable to detect links between environmental drivers and phenological metrics. We conclude that the current treatment of Avaritia Culicoides as a single group inhibits understanding of environmentally-driven spatial variation in species phenology and hinders the development of models for predicting the SVFP from environmental factors. Culicoides surveillance methods should be adapted to focus on concentrated assessments of species-specific abundance during the start and end of seasonal activity in temperate regions to facilitate refinement of ruminant movement restrictions thereby reducing the impact of Culicoides-borne arboviruses.
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Hartemink N, Vanwambeke SO, Purse BV, Gilbert M, Van Dyck H. Towards a resource-based habitat approach for spatial modelling of vector-borne disease risks. Biol Rev Camb Philos Soc 2014; 90:1151-62. [PMID: 25335785 DOI: 10.1111/brv.12149] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 09/18/2014] [Accepted: 09/25/2014] [Indexed: 11/30/2022]
Abstract
Given the veterinary and public health impact of vector-borne diseases, there is a clear need to assess the suitability of landscapes for the emergence and spread of these diseases. Current approaches for predicting disease risks neglect key features of the landscape as components of the functional habitat of vectors or hosts, and hence of the pathogen. Empirical-statistical methods do not explicitly incorporate biological mechanisms, whereas current mechanistic models are rarely spatially explicit; both methods ignore the way animals use the landscape (i.e. movement ecology). We argue that applying a functional concept for habitat, i.e. the resource-based habitat concept (RBHC), can solve these issues. The RBHC offers a framework to identify systematically the different ecological resources that are necessary for the completion of the transmission cycle and to relate these resources to (combinations of) landscape features and other environmental factors. The potential of the RBHC as a framework for identifying suitable habitats for vector-borne pathogens is explored and illustrated with the case of bluetongue virus, a midge-transmitted virus affecting ruminants. The concept facilitates the study of functional habitats of the interacting species (vectors as well as hosts) and provides new insight into spatial and temporal variation in transmission opportunities and exposure that ultimately determine disease risks. It may help to identify knowledge gaps and control options arising from changes in the spatial configuration of key resources across the landscape. The RBHC framework may act as a bridge between existing mechanistic and statistical modelling approaches.
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Affiliation(s)
- Nienke Hartemink
- Faculty of Veterinary Medicine, Department of Farm Animal Health, Utrecht University, Yalelaan 7, 3584 CL Utrecht, The Netherlands
| | - Sophie O Vanwambeke
- Georges Lemaître Centre for Earth and Climate Research (TECLIM), Earth and Life Institute, Université catholique de Louvain, Place Louis Pasteur 3 bte L4.03.07, B 1348, Louvain-la-Neuve, Belgium
| | - Bethan V Purse
- NERC Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Oxfordshire OX10 8BB, U.K
| | - Marius Gilbert
- Biological Control and Spatial Ecology, Université Libre de Bruxelles, ULB CP160/12, Avenue F. D. Roosevelt 50, 1050 Bruxelles, Belgium.,Fonds National de la Recherche Scientifique, F.R.S.-FNRS rue d'Egmont 5, B 1000 Brussels, Belgium
| | - Hans Van Dyck
- Behavioural Ecology and Conservation Group, Earth and Life Institute, Université catholique de Louvain, Croix du Sud 4-5 L7.07.04, B 1348, Louvain-la-Neuve, Belgium
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Scolamacchia F, VAN DEN Broek J, Meiswinkel R, Heesterbeek JAP, Elbers ARW. Principal climatic and edaphic determinants of Culicoides biting midge abundance during the 2007-2008 bluetongue epidemic in the Netherlands, based on OVI light trap data. MEDICAL AND VETERINARY ENTOMOLOGY 2014; 28:143-156. [PMID: 24148154 DOI: 10.1111/mve.12028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 06/02/2023]
Abstract
Palaearctic Culicoides midges (Diptera: Ceratopogonidae) represent a vital link in the northward advance of certain arboviral pathogens of livestock such as that caused by bluetongue virus. The effects of relevant ecological factors on weekly Culicoides vector abundances during the bluetongue virus serotype 8 epidemics in the Netherlands in 2007 and 2008 were quantified within a hurdle modelling framework. The relative role of meteorological parameters showed a broadly consistent association across species, with larger catches linked to temperature-related variables and lower wind speed. Moreover, vector abundance was found to be influenced by edaphic factors, likely related to species-specific breeding habitat preferences that differed markedly amongst some species. This is the first study on Culicoides vector species in the Netherlands identified during an entomological surveillance programme, in which an attempt is made to pinpoint the factors that influence midge abundance levels. In addition to providing key inputs into risk-mitigating tools for midge-borne pathogens and disease transmission models, the adoption of methods that explicitly address certain features of abundance datasets (frequent zero-count observations and over-dispersion) helped enhance the robustness of the ecological analysis.
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Affiliation(s)
- F Scolamacchia
- Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; Department of Epidemiology, Crisis Organization and Diagnostics, Central Veterinary Institute of Wageningen University, Lelystad, the Netherlands
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Diarra M, Fall M, Fall AG, Diop A, Seck MT, Garros C, Balenghien T, Allène X, Rakotoarivony I, Lancelot R, Mall I, Bakhoum MT, Dosum AM, Ndao M, Bouyer J, Guis H. Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal. Parasit Vectors 2014; 7:147. [PMID: 24690198 PMCID: PMC3973751 DOI: 10.1186/1756-3305-7-147] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 03/11/2014] [Indexed: 11/10/2022] Open
Abstract
Background The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site.
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Affiliation(s)
- Maryam Diarra
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l'Elevage et de Recherches Vétérinaires, Dakar, Sénégal.
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Robin M, Archer D, Garros C, Gardès L, Baylis M. The threat of midge-borne equine disease: investigation of Culicoides species on UK equine premises. Vet Rec 2014; 174:301. [PMID: 24508765 DOI: 10.1136/vr.102151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
There are concerns that outbreaks of exotic or novel vector-borne viral diseases will increasingly occur within northern Europe and the UK in the future. African horse sickness (AHS) is a viral disease of equids that is transmitted by Culicoides and is associated with up to 95 per cent mortality. AHS has never occurred in the UK; however, it has been suggested that appropriate Culicoides species and climatic conditions are present in northern Europe to support an outbreak. No data are currently available regarding the Culicoides species present on UK equine properties. This study demonstrates the presence of potential AHS virus vector Culicoides species on both urban and rural equine properties within the south-east UK. PCR analysis revealed that engorged members of these species contained equine DNA, proving a direct vector-host interaction. It is therefore possible that an AHS outbreak could occur in the UK if the virus were to be imported and, given the severe welfare and economic consequences of AHS, this would have devastating consequences to the naïve UK equine population.
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Affiliation(s)
- M Robin
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Chester High Road, Neston, Cheshire CH64 7TE
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The influence of the wind in the Schmallenberg virus outbreak in Europe. Sci Rep 2013; 3:3361. [PMID: 24285292 PMCID: PMC6506448 DOI: 10.1038/srep03361] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 11/11/2013] [Indexed: 11/30/2022] Open
Abstract
A model previously developed for the wind-borne spread by midges of bluetongue virus in NW Europe in 2006 is here modified and applied to the spread of Schmallenberg virus in 2011. The model estimates that pregnant animals were infected 113 days before producing malformed young, the commonest symptom of reported infection, and explains the spatial and temporal pattern of infection in 70% of the 3,487 affected farms, most of which were infected by midges arriving through downwind movement (62% of explained infections), or a mixture of downwind and random movements (38% of explained infections), during the period of day (1600–2100 h, i.e. dusk) when these insects are known to be most active. The main difference with Bluetongue is the higher rate of spread of SBV, which has important implications for disease control.
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Brugger K, Rubel F. Characterizing the species composition of European Culicoides vectors by means of the Köppen-Geiger climate classification. Parasit Vectors 2013; 6:333. [PMID: 24267276 PMCID: PMC4176262 DOI: 10.1186/1756-3305-6-333] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/19/2013] [Indexed: 11/13/2022] Open
Abstract
Background Biting midges of the genus Culicoides spp. (Diptera: Ceratopogonidae) are vectors for the Bluetongue virus, the African horse sickness virus and the recently emerged Schmallenberg virus. Here, species of the C. obsoletus complex, the C. pulicaris complex and C. imicola were considered. The objective was to compile a map of these Culicoides species and their relation to the popular climate classification defined by Wladimir Köppen and Rudolf Geiger to provide a quick view on the species composition in Europe. Findings Major parts of Central and Northern Europe are covered by a warm temperate fully humid climate, characterized by warm summers. For this so-called Cfb climate fractions of 89% C. obsoletus complex and 11% C. pulicaris complex were estimated. Further investigations comprise the continental climate Dfb (76% C. obsoletus, 24% C. pulicaris), the warm temperate climate with hot summers Cfa (35% C. obsoletus, 65% C. pulicaris), the warm temperate dry climate, characterized by warm summers Csb (38% C. obsoletus, 51% C. pulicaris, 11% C. imicola) and the warm temperate dry climate with hot summers Csa of the Mediterranean area (11% C. obsoletus, 12% C. pulicaris, 77% C. imicola). Conclusions A highly significant association coefficient of RV = 0.64 (Cramer’s V) confirms the correlation between Culicoides spp. and climate zones. Moreover, climate projections for the end of the century give an impression on expected changes in the European Culicoides spp. composition.
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Affiliation(s)
- Katharina Brugger
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria.
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