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No evidence for the persistence of Schmallenberg virus in overwintering mosquitoes
Scholte, E.J. ; Mars, M.H. ; Braks, M. ; Hartog, W. den; Ibanez-Justicia, A. ; Koopmans, M. ; Koenraadt, C.J.M. ; Vries, A. de; Reusken, C. - \ 2014
Medical and Veterinary Entomology 28 (2014)1. - ISSN 0269-283X - p. 110 - 115.
culex-pipiens diptera - simbu-group - culicoides-brevitarsis - genus orthobunyavirus - buttonwillow virus - ingwavuma virus - oropouche virus - sathuperi-virus - shamonda-virus - akabane virus
In 2011, Schmallenberg virus (SBV), a novel member of the Simbu serogroup, genus Orthobunyavirus, was identified as the causative agent of a disease in ruminants in Europe. Based on the current knowledge on arthropods involved in the transmission of Simbu group viruses, a role of both midges and mosquitoes in the SBV transmission cycle cannot be excluded beforehand. The persistence of SBV in mosquitoes overwintering at SBV-affected farms in the Netherlands was investigated. No evidence for the presence of SBV in 868 hibernating mosquitoes (Culex, Anopheles, and Culiseta spp., collected from January to March 2012) was found. This suggests that mosquitoes do not play an important role, if any, in the persistence of SBV during the winter months in northwestern Europe.
Prevalence of Coxiella Burnetii in Ticks After a Large Outbreak of Q Fever
Sprong, H. ; Tijsse-Klasen, E. ; Langelaar, M. ; Bruin, A. de; Fonville, M. ; Gassner, F. ; Takken, W. ; Wieren, S.E. van; Nijhof, A. ; Jongejan, F. ; Maassen, C.B.M. ; Scholte, E.J. ; Hovius, J.W. ; Emil Hovius, K. ; Spitalska, E. ; Duynhoven, Y.T. van - \ 2012
Zoonoses and Public Health 59 (2012)1. - ISSN 1863-1959 - p. 69 - 75.
ixodes-ricinus ticks - netherlands - slovakia - infection - animals - transmission - pathogens - anaplasma - borrelia - agent
Q fever has emerged as an important human and veterinary public health problem in the Netherlands with major outbreaks in three consecutive years. Goat farms are probably the prime source from which Coxiella burnetii have spread throughout the environment, infecting people living in the vicinity. Coxiella burnetii infection not only spilled over from animal husbandry to humans but could also have spread to neighbouring wildlife and pets forming novel reservoirs and consequently posing another and lingering threat to humans, companion animals and livestock. In these cases, transmission routes other than airborne spread of contaminated aerosols may become significant. Therefore, the role of ticks in the transmission of Coxiella burnetii in the current situation was investigated. A total of 1891 questing Ixodes ricinus ticks and 1086 ticks feeding on pets, wildlife and livestock were tested by a recently developed multiplex Q-PCR. All ticks were negative, except for a few ticks feeding on a herd of recently vaccinated sheep. Coxiella-positive ticks were not detected after resampling this particular herd three months later. Based on these data we conclude that the current risk of acquiring Q fever from questing ticks in the Netherlands is negligible. However, for future risk assessments, it might be relevant to sample more ticks in the vicinity of previously C. burnetii infected goat farms and to assess whether C. burnetii can be transmitted transovarially and transstadially in I. ricinus ticks.
Het toenemend belang van infectieziekten die worden overgebracht door vectoren
Scholte, E.J. ; Reusken, C.B.E.M. ; Takken, W. ; Jongejan, F. ; Giessen, J.W.B. van der - \ 2009
Infectieziekten bulletin 19 (2009)9. - ISSN 0925-711X - p. 311 - 316.
ziekten overgebracht door vectoren - infectieziekten - geleedpotigen - ziekten overgebracht door teken - ingevoerde infecties - klimaatverandering - zoönosen - ziekten overgebracht door muskieten - volksgezondheid - vector-borne diseases - infectious diseases - arthropods - tickborne diseases - imported infections - climatic change - zoonoses - mosquito-borne diseases - public health
Dit artikel gaat over de voor Nederland belangrijkste arthropodenvectoren (geleedpotigen, in dit artikel voornamelijk muggen en teken) en de door hen overgebrachte infectieziekten. Daarnaast wordt de rol van landschappelijke aanpassingen, klimaatverandering, intensiever internationaal reizigers- en handelsverkeer en veranderend gedrag met betrekking tot recreatie beschreven. Tenslotte wordt de verdere kennisbehoefte aangegeven
The hidden passenger of Lucky bamboo: Do imported Aedes albopictus mosquitoes cause Dengue virus transmission in the Netherlands?
Hofhuis, A. ; Reimerink, J. ; Reusken, C. ; Scholte, E.J. ; Boer, A. de; Takken, W. ; Koopmans, M.P.G. - \ 2009
Vector-Borne and Zoonotic Diseases 9 (2009)2. - ISSN 1530-3667 - p. 217 - 220.
Since 2005, Aedes albopictus mosquitoes have been detected in companies in the Netherlands that import ornamental plants from China. To assess the risks of dengue transmission, a study was carried out in 48 persons who are professionally exposed to these mosquitoes. No evidence for non-travel-related flavivirus infections was found
Accidental importation of the mosquito Aedes albopictus into the Netherlands: a survey of mosquito distribution and the presence of dengue virus
Scholte, E.J. ; Dijkstra, E. ; Blok, H. ; Vries, A. de; Takken, W. ; Hofhuis, A. ; Koopmans, M.P.G. ; Boer, A. de; Reusken, C.B.E.M. - \ 2008
Medical and Veterinary Entomology 22 (2008)4. - ISSN 0269-283X - p. 352 - 358.
stegomyia albopictus - primers - skuse
In the summer of 2005, the Asian tiger mosquito, Aedes albopictus (Skuse) (Diptera: Culicidae) was found for the first time in the Netherlands. It was collected on the premises of several horticultural companies that import the ornamental plant Dracaena sanderiana (Sparagalus: Dracaenaceae [Agavaceae]), known as Lucky bamboo, from southern China, an area endemic for this mosquito species and for arboviruses transmitted by this vector. Here we report the results of a 1-year survey of the distribution and vector status of Ae. albopictus in Lucky bamboo nurseries in the Netherlands (July 2006-June 2007). As it had been established previously that the presence of this species was linked to the import of Lucky bamboo, the survey was conducted only on sites owned by relevant import companies. In total, 569 adult Ae. albopictus were collected with mosquito traps from 15 of the 17 (88%) glasshouses used by Lucky bamboo importers, none of which were found to be infected with dengue virus. On two occasions there was evidence that Ae. albopictus had escaped from the glasshouses, but, overall, there was no evidence that a population had become established in the greenhouses or elsewhere.
The phenology and population dynamics of Culicoides spp. in different ecosystems in the Netherlands
Takken, W. ; Verhulst, N.O. ; Scholte, E.J. ; Jacobs, F.H.H. ; Jongema, Y. ; Lammeren, R.J.A. van - \ 2008
Preventive Veterinary Medicine 87 (2008)1-2. - ISSN 0167-5877 - p. 41 - 54.
bluetongue virus vector - obsoletus diptera - imicola diptera - tsetse-flies - south-africa - ceratopogonidae - europe - identification - transmission - glossinidae
The Netherlands has enjoyed a relatively free state of vector-borne diseases of economic importance for more than one century. Emerging infectious diseases may change this situation, threatening the health of humans, domestic livestock and wildlife. In order to be prepared for the potential outbreak of vector-borne diseases, a study was undertaken to investigate the distribution and seasonal dynamics of candidate vectors of infectious diseases with emphasis on bluetongue vectors (Culicoides spp.). The study focused primarily on the relationship between characteristic ecosystems suitable for bluetongue vectors and climate, as well as on the phenology and population dynamics of these vectors. Twelve locations were selected, distributed over four distinct habitats: a wetland area, three riverine systems, four peat land areas and four livestock farms. Culicoides populations were sampled continuously using CO2-baited counterflow traps from July 2005 until August 2006, with an interruption from November 2005 to March 2006. All vectors were identified to species level. Meteorological and environmental data were collected at each location. Culicoides species were found in all four different habitat types studied. Wetland areas and peat bogs were rich in Culicoides spp. The taxonomic groups Culicoides obsoletus (Meigen) and Culicoides pulicaris (Linnaeus) were strongly associated with farms. Eighty-eight percent of all Culicoides consisted of the taxon C. obsoletus/Culicoides scoticus. On the livestock farms, 3% of Culicoides existed of the alleged bluetongue vector Culicoides dewulfi Goetghebuer. Culicoides impunctatus Goetghebuer was strongly associated with wetland and peat bog. Many Culicoides species were found until late in the phenological season and their activity was strongly associated with climate throughout the year. High annual variations in population dynamics were observed within the same study areas, which were probably caused by annual variations in environmental conditions. The study demonstrates that candidate vectors of bluetongue virus are present in natural and livestock-farm habitats in the Netherlands, distributed widely across the country. Under favourable climatic conditions, following virus introduction, bluetongue can spread among livestock (cattle, sheep and goats), depending on the nature of the viral serotype. The question now arises whether the virus can survive the winter conditions in north-western Europe and whether measures can be taken that effectively halt further spread of the disease.
African water storage pots for the delivery of the Entomopathogenic fungus Metarhizium anisopliae to the Malaria vectors Anopheles gambiae s.s. and Anopheles funestus
Farenhorst, M. ; Farina, D. ; Scholte, E.J. ; Takken, W. ; Hunt, R.H. ; Coetzee, M. ; Knols, B.G.J. - \ 2008
American Journal of Tropical Medicine and Hygiene 78 (2008)6. - ISSN 0002-9637 - p. 910 - 916.
western kenya - mosquitos - transmission - infection - complex
We studied the use of African water storage pots for point source application of Metarhizium anisopliae against the malaria vectors Anopheles gambiae s.s. and An. funestus. Clay pots were shown to be attractive resting sites for male and female An. gambiae s.s. and were not repellent after impregnation with fungus. M. anisopliae was highly infective and virulent after spray application inside pots. At a dosage of 4 x 1010 conidia/m2, an average of 95 ± 1.2% of An. gambiae s.s. obtained a fungal infection. A lower dosage of 1 x 1010 conidia/m2 infected an average of 91.5 ± 0.6% of An. gambiae s.s. and 91.8 ± 1.2% of An. funestus mosquitoes. Fungal infection significantly reduced mosquito longevity, as shown by differences between survival curves and LT50 values. These pots are suitable for application of entomopathogenic fungi against malaria vectors and their potential for sustainable field implementation is discussed.
Advies ter bestrijding van Aedes albopictus in kassen in Nederland
Scholte, E.J. ; Takken, W. - \ 2007
Wageningen : Plantenziektenkundige Dienst - 1
culicidae - aedes albopictus - larven - kassen - bestrijdingsmethoden - pesticiden - nederland - glastuinbouw - larvae - greenhouses - control methods - pesticides - netherlands - greenhouse horticulture
Adviezen ter bestrijding van de larven van de tijgermug Aedes albopictus en adulten die voorkomen in de kassen van tuinbouwbedrijven die de zgn. Lucky bamboo (dracaena sanderiana) importeren
Occurrence and distribution of Aedes albopictus (Skuse) in the Netherlands; survey 2006-2007 : report
Scholte, E.J. ; Takken, W. - \ 2007
Wageningen : Department of Entomology, Dutch Plant Protection Service - 16
culicidae - aedes albopictus - populaties - distributie - dracaena sanderiana - import - ondernemingen - tellingen - nederland - populations - distribution - imports - enterprises - censuses - netherlands
In the summer of 2005, the Asian tigermosquito (Aedes albopictus) was found for the first time in the Netherlands. It was intercepted in several horticultural companies that import the ornamental plant Lucky bamboo from southern China, an endemic area for this mosquito species. The current report describes the results from a one-year survey that was carried out to study the distribution of Aedes albopictus in the Netherlands (July 2006-June 2007). Since the presence of this species is directly linked to the continuous import of Lucky bamboo the focus of the survey was aimed at these companies
Infection of adult Aedes aegypti and Ae. albopictus mosquitoes with the entomopathogenic fungus Metarhizium anisopliae
Scholte, E.J. ; Takken, W. ; Knols, B.G.J. - \ 2007
Acta Tropica 102 (2007)3. - ISSN 0001-706X - p. 151 - 158.
insecticide resistance - culex-quinquefasciatus - anopheles-gambiae - disease-control - dengue - malaria - diptera - deltamethrin - transmission - populations
This study describes a laboratory investigation on the use of the insect-pathogenic fungus Metarhizium anisopliae against adult Aedes aegypti and Ae. albopictus mosquitoes. At a dosage of 1.6 × 1010 conidia/m2, applied on material that served as a mosquito resting site, an average of 87.1 ± 2.65% of Ae. aegypti and 89.3 ± 2.2% of Ae. albopictus became infected with the fungus. The life span of fungus-contaminated mosquitoes of both species was significantly reduced compared to uninfected mosquitoes. LT50-values of fungus-contaminated mosquitoes ranged between 3.1 ± 0.2 days (male Ae. aegypti) and 4.1 ± 0.3 days (female Ae. aegypti). LT50-values of uncontaminated mosquitoes ranged from 17.7 ± 0.4 days (female Ae. albopictus) to 19.7 ± 0.6 days (male Ae. albopictus). These results indicate that both mosquito species are highly susceptible to infection with this entomopathogen. Requirements for developing and incorporating this biological control method into current strategies to control major diseases vectored by these species, such as dengue fever, are discussed.
The Asian tiger mosquito (Aedes albopictus) in the Netherlands: should we worry?
Scholte, E.J. ; Dijkstra, E. ; Ruijs, H. ; Jacobs, F. ; Takken, W. ; Hofhuis, A. ; Reusken, C. ; Koopmans, M. ; Boer, A. de - \ 2007
Proceedings of the Netherlands Entomological Society meeting 18 (2007). - ISSN 1874-9542 - p. 131 - 135.
|Distribution and dynamics of arthropod vectors of zoonotic disease in the Netherlands in relation to risk of disease transmission
Takken, W. ; Verhulst, N.O. ; Scholte, E.J. ; Jacobs, F.H.H. ; Jongema, Y. ; Lammeren, R.J.A. van; Bergsma, A.R. ; Klok, T.C. ; Roermund, H.J.W. van; Koeijer, A.A. de; Borgsteede, F.H.M. - \ 2007
Wageningen : Wageningen University - 59 p.
|How to select non-target arthropods for GM environmental risk assessment?
Dicke, M. ; Scholte, E.J. - \ 2006
In: 1st Meeting of European Advisory Committees on Biosafety in the field of deliberate release of GMOs, Amsterdam 19-20 January 2006 Amsterdam : - p. 13 - 13.
Infection of the malaria mosquito Anopheles gambiae with the entomopathogenic fungus Metarhizium anisopliae reduces blood feeding and fecundity
Scholte, E.J. ; Knols, B.G.J. ; Takken, W. - \ 2006
Journal of Invertebrate Pathology 91 (2006)1. - ISSN 0022-2011 - p. 43 - 49.
schistocerca-gregaria - desert locust - destruxins - reduction - flavoviride - consumption - longevity - culicidae - pathogen - survival
The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent against adult African malaria vectors. In addition to causing significant mortality, this pathogen is known to cause reductions in feeding and fecundity in a range of insects. In the present study we investigated whether infection with M. anisopliae affected blood feeding and fecundity of adult female malaria vectors Anopheles gambiae Giles sensu stricto. Mosquitoes were contaminated with either a low or a moderately high dose of oil-formulated conidia of M. anisopliae, and offered a single human blood meal 48, 72, or 96 h later to assess feeding propensity and individual blood meal size. In a second experiment, individual fungus-infected females were offered a blood meal every third day (to a total of 8 gonotrophic cycles), and allowed to oviposit after each cycle in order to quantify feeding propensity and fecundity. Infected females took smaller blood meals and displayed reduced feeding propensity. It was found that mosquitoes, inoculated with a moderately high dose of fungal conidia, exhibited reduced appetite related to increasing fungal growth. Of the fungus-infected females, the proportion of mosquitoes taking the second blood meal was reduced with 51%. This was further reduced to 35.3% by the 4th blood meal. During 8 feeding opportunities, the average number of blood meals taken by uninfected females was 4.39, against 3.40 (low dose), and 2.07 (high dose) blood meals for the fungus-infected females. Moreover, infected females produced fewer eggs per gonotrophic cycle and had a lower life-time fecundity. Epidemiological models show that both blood feeding and fecundity are among the most important factors affecting the likelihood of a mosquito transmitting malaria, which suggests that this fungus may have potential as biocontrol agent for vector-borne disease control
A study on avoidance and repellency of the African malaria vector Anopheles gambiae upon exposure to the entomopathogenic fungus Metarhizium anisopliae
Scholte, E.J. ; Knols, B.G.J. ; Takken, W. - \ 2005
Proceedings of the Netherlands Entomological Society meeting 16 (2005). - ISSN 1874-9542 - p. 131 - 138.
An entomopathogenic fungus for control of adult African malaria mosquitoes
Scholte, E.J. ; Ng'habi, K.R.N. ; Kihonda, J. ; Takken, W. ; Paaijmans, K.P. ; Abdulla, S. ; Killeen, G.F. ; Knols, B.G.J. - \ 2005
Science 308 (2005)5728. - ISSN 0036-8075 - p. 1641 - 1642.
insecticide-treated nets - south-africa
Biological control of malaria mosquitoes in Africa has rarely been used in vector control programs. Recent developments in this field show that certain fungi are virulent to adult Anopheles mosquitoes. Practical delivery of an entomopathogenic fungus that infected and killed adult Anopheles gambiae, Africa's main malaria vector, was achieved in rural African village houses. An entomological inoculation rate model suggests that implementation of this vector control method, even at the observed moderate coverage during a field study in Tanzania, would significantly reduce malaria transmission intensity
|Selection of non-target organisms for laboratory tests of transgenic crops
Scholte, E.J. ; Dicke, M. - \ 2005
In: Ecological Impact of Genetically Modified Organisms, IOBC/WPRS working group on GMOS in Int. Plant Production, Lleida, Catalonia, Spain, 1-3-2005 Lleida, Catalonia, Spain : IOBC/WPRS - p. 35 - 35.
|Effects of insect-resistant transgenic crops on non-target arthropods: first step in pre-market risk assessment studies
Scholte, E.J. ; Dicke, M. - \ 2005
Bilthoven : Commissie Genetische Modificatie
Letter to the Editor: Benefits and risks in malaria control - Response
Thomas, M.B. ; Blanford, S. ; Jenkins, N.E. ; Killeen, G.F. ; Knols, B.G.J. ; Read, A.F. ; Scholte, E.J. ; Takken, W. - \ 2005
Science 310 (2005)5745. - ISSN 0036-8075 - p. 49 - 51.
Autodissemination of the entomopathogenic fungus Metarhizium anisopliae amongst adults of the malaria vector anopheles gambiae s.s.
Scholte, E.J. ; Knols, B.G.J. ; Takken, W. - \ 2004
Malaria Journal 3 (2004). - ISSN 1475-2875 - 6 p.
popillia-japonica coleoptera - insecticide resistance - beauveria-bassiana - japanese-beetle - pheromone trap - infection - diptera - africa - entomophthorales - yponomeutidae
Background - The entomopathogenic fungus Metarhizium anisopliae is being considered as a biocontrol agent for adult African malaria vectors. In the laboratory, work was carried out to assess whether horizontal transmission of the pathogen can take place during copulation, as this would enhance the impact of the fungus on target populations when compared with insecticides. Methods - Virgin female Anopheles gambiae sensu stricto were exposed to conidia whilst resting on fungus-impregnated paper. These females were then placed together for one hour with uncontaminated males in proportions of either 1:1 or 1:10 shortly before the onset of mating activity. Results - Males that had acquired fungal infection after mating indicate that passive transfer of the pathogen from infected females does occur, with mean male infection rates between 10.7 ± 3.2% and 33.3 ± 3.8%. The infections caused by horizontal transmission did not result in overall differences in survival between males from test and control groups, but in one of the three experiments the infected males had significantly shorter life spans than uninfected males (P <0.05). Conclusion - This study shows that autodissemination of fungal inoculum between An. gambiae s.s. mosquitoes during mating activity is possible under laboratory conditions. Field studies are required next, to assess the extent to which this phenomenon may augment the primary contamination pathway (i.e. direct contact with fungus-impregnated targets) of vector populations in the field.