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Groschupp S, Kampen H, Werner D. Winter activity of Culicoides (Diptera: Ceratopogonidae) inside and outside stables in Germany. MEDICAL AND VETERINARY ENTOMOLOGY 2024. [PMID: 39187966 DOI: 10.1111/mve.12756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 08/07/2024] [Indexed: 08/28/2024]
Abstract
Culicoides biting midge species (Diptera: Ceratopogonidae) of the Obsoletus Group and the Pulicaris Complex are considered the major vectors of bluetongue and Schmallenberg viruses in Europe. Overwintering strategies of these arboviruses are controversially discussed, with the ongoing activity of vector species and a non-disrupted transmission cycle during winter being a plausible explanation. Although data on Culicoides winter activity are relatively scant, a seasonal vector-free period (SVFP), during which adult Culicoides are not or hardly active, is questionable. To determine winter activity and define SVFPs according to the EU Commission Regulation No 1266/2007, adult Culicoides were trapped weekly with UV-light traps from October to April 2019/2020 and 2020/2021 inside and outside stables on 16 farms throughout Germany. Temperature measurements were taken regularly at each trapping site since the temperature is a known driver of biting midge activity. In 960 indoor and outdoor catches, 32,377 Culicoides were trapped, with 90.9% of them belonging to the Obsoletus Group, 6.1% to the Pulicaris Complex and 3.0% to 'other Culicoides' according to morphological identification. The majority (61.3%) of Culicoides were trapped indoors, with substantial numbers of specimens collected from October to December, in March and in April, and only a few or no specimens in January and February. Obsoletus Group biting midges were active indoors for almost the entire winter. Outdoors, Culicoides numbers decreased from October to December, few or no specimens were caught from January to March, and high numbers were captured in April. Of the collected Culicoides, 2028 were blood-fed, of which 94.6% were trapped in the stables. The indoor SVFP, although calculated for blood-fed instead of parous females, lasted for almost 4 months (late November until mid-March) in winter 2019/2020 and 2 months (January and February) in winter 2020/2021. The outdoor SVFPs covered almost the entire study period in both winters, with slight differences between the onsets and the ends. The Culicoides activity significantly depended on temperature. Specimens of the Obsoletus Group were caught at an average temperature of 7.4°C (minimum 0.3°C) and of the Pulicaris Complex at an average temperature of 10.3°C (minimum 1.2°C). These temperatures were reached inside the stables over more extended periods than outside. The average indoor temperatures were 1.2 K higher than the average outdoor temperatures, although absolute temperature differences of up to 9.0 K were recorded. Based on Culicoides activity, the results of the present study indicate an almost continuous potential for virus transmission in winter within livestock houses.
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Affiliation(s)
- Sarah Groschupp
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Helge Kampen
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Infectology, Greifswald, Germany
| | - Doreen Werner
- Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
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Mestre F, Pereira AL, Araújo MB. Climate correlates of bluetongue incidence in southern Portugal. MEDICAL AND VETERINARY ENTOMOLOGY 2024. [PMID: 39031652 DOI: 10.1111/mve.12738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 06/10/2024] [Indexed: 07/22/2024]
Abstract
Model forecasts of the spatiotemporal occurrence dynamics of diseases are necessary and can help understand and thus manage future disease outbreaks. In our study, we used ecological niche modelling to assess the impact of climate on the vector suitability for bluetongue disease, a disease affecting livestock production with important economic consequences. Specifically, we investigated the relationship between the occurrence of bluetongue outbreaks and the environmental suitability of each of the four vector species studied. We found that the main vector for bluetongue disease, Culicoides imicola, a typically tropical and subtropical species, was a strong predictor for disease outbreak occurrence in a region of southern Portugal from 2004 to 2021. The results highlight the importance of understanding the climatic factors that might influence vector presence to help manage infectious disease impacts. When diseases impact economically relevant species, the impacts go beyond mortality and have important economic consequences.
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Affiliation(s)
- Frederico Mestre
- 'Rui Nabeiro' Biodiversity Chair-Mediterranean Institute for Agriculture, Environment and Development (MED) & Global Change and Sustainability Institute, Institute for Advanced Studies and Research (CHANGE), Universidade de Évora, Évora, Portugal
| | | | - Miguel B Araújo
- 'Rui Nabeiro' Biodiversity Chair-Mediterranean Institute for Agriculture, Environment and Development (MED) & Global Change and Sustainability Institute, Institute for Advanced Studies and Research (CHANGE), Universidade de Évora, Évora, Portugal
- Department of Biogeography and Global Change, National Museum of Natural Sciences, CSIC, Madrid, Spain
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Žiegytė R, Palinauskas V, Bernotienė R. Natural Vector of Avian Haemoproteus asymmetricus Parasite and Factors Altering the Spread of Infection. INSECTS 2023; 14:926. [PMID: 38132599 PMCID: PMC10743420 DOI: 10.3390/insects14120926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/22/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023]
Abstract
Avian haemosporidians (Apicomplexa, Haemosporida) are widespread blood protists, often causing severe haemosporidiosis, pathology, or even mortality in their hosts. Migrant birds regularly bring various haemosporidian parasites from wintering grounds to European breeding areas. Some haemosporidian parasites are prevalent in breeding sites and complete their life cycles in temperate climate zones and can be transmitted, but others do not. The factors altering the spread of these haemosporidians are not fully understood. Culicoides biting midges (Diptera: Ceratopogonidae) play an important role in the transmission of worldwide distributed avian haemosporidian parasites belonging to the genus Haemoproteus, but this information is particularly scarce and insufficient. The key factors limiting the spread of these pathogens in temperate climate zones, which we suspect and aim to study, are the absence of susceptible vectors and the ecological isolation of birds from vectors during the breeding period when transmission occurs. The primary objective of this study was to evaluate how the habitats of biting midges and bird breeding sites influence parasite transmission while also seeking to expand our understanding of the natural vectors for these parasites. Biting midges were collected using UV traps on the Curonian Spit, Lithuania, in different habitats, such as woodland and reeds, from May to September. Parous Culicoides females were identified, dissected, and investigated for the presence of Haemoproteus parasites using both microscopy and PCR-based tools. Among the dissected 1135 parous Culicoides females, the sporozoites of Haemoproteus asymmetricus (genetic lineage hTUPHI01) have been detected for the first time in the salivary glands of Culicoides festivipennis. The sporozoites of four Haemoproteus lineages were detected in Culicoides segnis, C. festivipennis, and Culicoides kibunensis biting midges. PCR-based screening showed that the females of seven Culicoides species were naturally infected with Haemoproteus parasites. The DNA of the parasite of owls, Haemoproteus syrnii (hSTAL2), was detected for the first time in Culicoides punctatus. The highest abundance of collected Culicoides females was in June, but the highest prevalence of Haemoproteus parasites in biting midges was in July. The abundance of Culicoides was higher in the woodland compared with reeds during the season. The acquired findings indicate the varied abundance and diversity of biting midges throughout the season and across distinct habitats. This variability could potentially impact the transmission of Haemoproteus parasites among birds with diverse breeding site ecologies. These outcomes hold the potential to enhance our understanding of the epizootiology of Haemoproteus infections within temperate climatic zones.
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Affiliation(s)
- Rita Žiegytė
- Nature Research Centre, Akademijos 2, 08412 Vilnius, Lithuania;
| | | | - Rasa Bernotienė
- Nature Research Centre, Akademijos 2, 08412 Vilnius, Lithuania;
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Osborne CJ, Cohnstaedt LW, Silver KS. Outlook on RNAi-Based Strategies for Controlling Culicoides Biting Midges. Pathogens 2023; 12:1251. [PMID: 37887767 PMCID: PMC10610143 DOI: 10.3390/pathogens12101251] [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: 09/14/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/28/2023] Open
Abstract
Culicoides are small biting midges with the capacity to transmit important livestock pathogens around much of the world, and their impacts on animal welfare are likely to expand. Hemorrhagic diseases resulting from Culicoides-vectored viruses, for example, can lead to millions of dollars in economic damages for producers. Chemical insecticides can reduce Culicoides abundance but may not suppress population numbers enough to prevent pathogen transmission. These insecticides can also cause negative effects on non-target organisms and ecosystems. RNA interference (RNAi) is a cellular regulatory mechanism that degrades mRNA and suppresses gene expression. Studies have examined the utility of this mechanism for insect pest control, and with it, have described the hurdles towards producing, optimizing, and applying these RNAi-based products. These methods hold promise for being highly specific and environmentally benign when compared to chemical insecticides and are more transient than engineering transgenic insects. Given the lack of available control options for Culicoides, RNAi-based products could be an option to treat large areas with minimal environmental impact. In this study, we describe the state of current Culicoides control methods, successes and hurdles towards using RNAi for pest control, and the necessary research required to bring an RNAi-based control method to fruition for Culicoides midges.
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Affiliation(s)
- Cameron J. Osborne
- Department of Entomology, College of Agriculture, Kansas State University, Manhattan, KS 66506, USA;
| | - Lee W. Cohnstaedt
- Foreign Arthropod-Borne Animal Diseases Research Unit, National Bio- and Agro-Defense Facility, Agricultural Research Service, United Stated Department of Agriculture, Manhattan, KS 66502, USA
| | - Kristopher S. Silver
- Department of Entomology, College of Agriculture, Kansas State University, Manhattan, KS 66506, USA;
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Groschupp S, Kampen H, Werner D. Occurrence of putative Culicoides biting midge vectors (Diptera: Ceratopogonidae) inside and outside barns in Germany and factors influencing their activity. Parasit Vectors 2023; 16:307. [PMID: 37653421 PMCID: PMC10472570 DOI: 10.1186/s13071-023-05920-z] [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: 05/23/2023] [Accepted: 08/09/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUND After several years without bluetongue disease, a ruminant illness caused by Culicoides-borne bluetongue virus (BTV), two new autochthonous cases were reported in 2018 in Germany. By contrast, Schmallenberg virus (SBV), another Culicoides-borne virus pathogenic to ruminants, has continuously circulated in Germany since its first emergence in 2011. The disease outbreaks have triggered numerous studies on the biology of the Culicoides vectors, but many ecological details are still obscure. METHODS Culicoides biting midge species were collected with UV-light traps on 10 farms in Germany, with one trap inside and one trap outside barns on each of the farms. Traps were run once a week for 24 h from January to December 2019. Collected biting midges were morphologically identified, counted and statistically evaluated, with a focus on the Obsoletus Group and the Pulicaris Complex of the ceratopogonid genus Culicoides, which are believed to contain the major virus vectors. Temperature and relative humidity recorded at each trap were linked to the quantity of caught Culicoides. Correlations between relative Culicoides abundance and presence of livestock or type of husbandry were also investigated. RESULTS A total of 38,886 Culicoides biting midges were trapped, with most of them belonging to the Obsoletus Group (51.0%) and the Pulicaris Complex (38.8%). The majority of captured specimens were collected in traps inside the barns. Obsoletus Group individuals were caught from late January to the last week of December while Pulicaris Complex individuals were captured from the end of March to early December. The lowest average temperatures at which members of the two groups were collected were 10.7 °C and 12.8 °C, respectively. While temperature had a statistically significant effect on the activity of both the Obsoletus Group and the Pulicaris Complex, relative humidity only significantly affected the activity of the latter. The presence of livestock significantly influenced the number of captured Obsoletus Group, but not of Pulicaris Complex specimens. Inside the barns, no statistical difference was found between numbers of caught Obsoletus Group and Pulicaris Complex specimens in livestock holdings with deep litter and manure scraper or slatted floor husbandry systems. CONCLUSIONS The almost year-round presence of Obsoletus Group biting midges and the demonstrated high relative abundance of other potential Culicoides vector species inside barns suggest a high risk of indoor virus transmission to ruminants should BTV or SBV circulate locally. Appropriate structural, organisational and vector control measures to reduce biting midge exposure should be implemented.
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Affiliation(s)
- Sarah Groschupp
- Research Area 2 “Landscape Use and Governance”, Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374 Müncheberg, Germany
| | - Helge Kampen
- Friedrich-Loeffler-Institut–Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald, Germany
| | - Doreen Werner
- Research Area 2 “Landscape Use and Governance”, Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374 Müncheberg, Germany
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Stokes JE, Carpenter S, Sanders C, Gubbins S. Emergence dynamics of adult Culicoides biting midges at two farms in south-east England. Parasit Vectors 2022; 15:251. [PMID: 35820957 PMCID: PMC9277857 DOI: 10.1186/s13071-022-05370-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/01/2022] [Indexed: 11/24/2022] Open
Abstract
Background Culicoides biting midges (Diptera: Ceratopogonidae) are biological vectors of livestock arboviruses that cause diseases with significant economic, social and welfare impacts. Within temperate regions, livestock movement during arbovirus outbreaks can be facilitated by declaring a ‘seasonal vector-free period’ (SVFP) during winter when adult Culicoides are not active. In this study we carry out long-term monitoring of Culicoides adult emergence from larval development habitats at two farms in the UK to validate current definitions of the SVFP and to provide novel bionomic data for known vector species. Methods Standard emergence traps were used to collect emerging adult Culicoides from dung heaps at two cattle farms in the south-east of England from June to November 2016 and March 2017 to May 2018. Culicoides were morphologically identified to species or complex level and count data were analysed using a simple population dynamic model for pre-adult Culicoides that included meteorological components. Results More than 96,000 Culicoides were identified from 267 emergence trapping events across 2 years, revealing clear evidence of bivoltinism from peaks of male populations of Culicoidesobsoletus emerging from dung heaps. This pattern was also reflected in the emergence of adult female Obsoletus complex populations, which dominated the collections (64.4% of total catch) and emerged throughout the adult active period. Adult male C. obsoletus were observed emerging earlier than females (protandry) and emergence of both sexes occurred throughout the year. Culicoides chiopterus and Culicoides scoticus were also identified in spring emergence collections, providing the first evidence for the overwintering of larvae in dung heaps for these species. Conclusions This study demonstrates continual and highly variable rates of emergence of Culicoides throughout the year. A lack of evidence for mass emergence in spring along with the ability to observe male generations highlights the need for complementary surveillance techniques in addition to light-trap data when investigating seasonality and phenology. Evidence was found of other vector species, C. chiopterus and C. scoticus, utilising cattle dung heaps as an overwintering habitat, further highlighting the importance of these habitats on farms. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05370-z.
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Affiliation(s)
- Jessica Eleanor Stokes
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK. .,ProScience Ltd, Gloucestershire, GL11 5SD, UK.
| | - Simon Carpenter
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK
| | | | - Simon Gubbins
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK
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