Publications by authors named "Jeroen Spitzen"
In temperate regions, female Culex pipiens biotype pipiens mosquitoes undergo diapause in winter. Diapausing biotype pipiens mosquitoes are potentially important winter reservoirs for mosquito-borne viruses, such as West Nile virus (WNV), Usutu virus (USUV), and Sindbis virus (SINV). Mosquitoes in diapause have not taken a bloodmeal prior to winter.
View Article and Find Full Text PDFBackground: Glass membrane feeders are used in malaria research for artificial blood feeding. This study investigates the use of Hemotek membrane feeders as a standardized alternative feeding system.
Methods: Hemotek feeders were compared with glass feeders by assessing mosquito feeding rate, imbibed blood meal volume and Plasmodium falciparum infection intensity on mosquito guts.
Article Synopsis
- Genomic analyses in temperate Europe show that mosquito-borne viruses can persist over winter, but the mechanisms behind this survival are still unclear.
- This study investigated whether diapausing mosquitoes in the Netherlands could harbor West Nile virus (WNV), Usutu virus (USUV), and Sindbis virus (SINV) during winter outbreaks.
- Despite collecting 4200 mosquitoes and conducting extensive virus screening, no evidence of virus persistence was found, suggesting the need for further research on other potential ways these viruses survive winter.
Collecting blood-fed mosquitoes to monitor pathogen presence or to gather information on the host blood meal is often challenging. Fermenting molasses can be used to produce carbon dioxide to attract host-seeking mosquitoes, however, earlier work indicated that it may also attract blood-fed mosquitoes in the field. In the current study, these field results were validated in an experimental setting using a large cage setup with Anopheles coluzzii (Diptera, Culicidae).
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- Flying insects like mosquitoes have developed skills to dodge threats, particularly useful for blood-feeding species to avoid being swatted.
- The study focused on how flight unpredictability and maneuverability affect the escape abilities of two mosquito species, Aedes aegypti (day-active) and Anopheles coluzzii (night-active), under different lighting conditions.
- Findings reveal that each species increases their escape performance in their natural feeding light: Anopheles rely on erratic flight at night, while Aedes improve their maneuverability in overcast daylight, providing insights for better mosquito control strategies.
Article Synopsis
- Mosquitoes use various cues like CO and human-mimicking odors to find hosts for blood meals, leading to the development of traps that employ these cues for monitoring and potential vector control.
- The study focused on enhancing trap performance by incorporating short-range host cues (heat and humidity) into a new trap called the M-Tego and analyzing their effects on mosquito flight behavior and capture rates.
- Results showed that the M-Tego, when providing heat and humidity, significantly increased mosquito captures, nearly doubling the rate compared to traditional traps, as mosquitoes were more attracted and spent more time near the enhanced trap.
Article Synopsis
- The study investigates the effects of sublethal doses of the larvicide Bacillus thuringiensis var. israelensis (Bti) on the development and behavior of adult Anopheles coluzzii mosquitoes after larvae exposure.
- It was found that larvae exposed to lower concentrations of Bti for 48 hours resulted in shorter adult lifespans and larger body sizes compared to unexposed control mosquitoes.
- There were no significant changes in the oviposition rates (egg-laying) of the female mosquitoes, indicating mixed effects on reproduction despite the influence on longevity and size.
Article Synopsis
- Mosquito oviposition behavior is influenced by chemical cues produced by larvae of Anopheles gambiae, with first instar larvae attracting gravid females, while fourth instar larvae deter them.
- Four key chemicals affecting oviposition were identified: dimethyldisulfide (DMDS), dimethyltrisulfide (DMTS), nonane, and 2,4-pentanedione (2,4-PD), where DMDS and DMTS were linked to egg retention and deterrence, and nonane and 2,4-PD showed mixed results.
- Laboratory and semi-field studies indicated that DMDS and DMTS deterred oviposition, whereas nonane and 2,4-PD
Article Synopsis
- - Female mosquitoes, particularly Anopheles coluzzii, use various cues to choose the best oviposition sites for laying eggs, with the presence of larvae playing a crucial role in this decision-making process.
- - Lower developmental stage larvae positively influence the decision to lay eggs, while higher stages can deter this choice, especially when larval visibility and density come into play.
- - The impact of larvae on oviposition is largely guided by olfactory cues, indicating that live larvae release chemicals affecting female reproductive success; however, water conditioned by larvae alone does not have the same effect.
Article Synopsis
- West Nile virus (WNV) is primarily transmitted by Culex pipiens mosquitoes, which have two biotypes: pipiens (diapausing in winter) and molestus (actively feeding in winter).
- A study identified that 92% of the diapausing Cx. pipiens were biotype pipiens, with over 70% of these surviving more than four months in sheds, while none survived in houses.
- Both diapausing and non-diapausing Cx. pipiens showed comparable vector competence for WNV, indicating that overwintering does not negatively impact their ability to transmit the virus.
Article Synopsis
- Host-seeking mosquitoes use various sensory cues to locate blood hosts and evade detection, which aids in the development of odour-baited traps for monitoring disease-carrying mosquitoes.
- This study focused on the close-range flight behavior of female malaria mosquitoes near an odour-baited trap, analyzing over 2500 flight tracks in both hanging and standing orientations.
- Findings revealed two distinct flight behaviors when approaching the trap: mosquitoes tended to fly downwards when approaching and quickly accelerated upwards when near, influencing their capture dynamics and providing insights for enhancing trap effectiveness in vector control.
Article Synopsis
- Most malaria infections occur indoors when mosquitoes enter through open structures like eaves and windows, making house modifications, like closing eaves, an effective strategy to reduce their entry and complement other prevention methods, such as insecticide-treated bed nets.! -
- A study conducted in southern Malawi tested 25 houses modified with different eave closure statuses (fully closed, partially closed, and open) over 25 nights, sampling mosquitoes using CDC light traps to assess the impact on mosquito entry rates.! -
- Results showed that houses with fully open eaves had 14 times more malaria-carrying mosquitoes than those with fully closed eaves, and even partially closed eaves allowed significantly more mosquitoes inside, highlighting the importance of complete e
The health impact of mosquito-borne diseases causes a huge burden on human societies. Recent vector control campaigns have resulted in promising declines in incidence and prevalence of these diseases, notably malaria, but resistance to insecticides and drugs are on the rise, threatening to overturn these gains. Moreover, several vector-borne diseases have re-emerged, requiring prompt and effective response measures.
View Article and Find Full Text PDFInsecticide-treated nets are currently a major tool to reduce malaria transmission. Their level of repellency affects contact of the mosquito with the net, but may also influence the mosquito's entry into the house. The response of host-seeking malaria mosquitoes approaching the eave of an experimental house was recorded within a large screen house.
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- A study investigated how malaria mosquitoes, specifically Anopheles gambiae, enter houses, focusing on their flight behavior and approach to eaves using 3D visualizations.
- The research was conducted in a semi-field setting in western Kenya, where mosquitoes' responses to an attractive synthetic odour blend and CO2 were analyzed.
- Results showed that while most mosquitoes approached at eave level and within a 180-degree arc, more than half did not enter immediately and spent significant time close to the eave before eventually passing through.
Article Synopsis
- The study investigated how both insecticide-resistant and susceptible malaria mosquitoes behave when approaching deltamethrin-treated nets using a wind tunnel approach.
- It found no significant differences in response times or spatial distribution between resistant and susceptible mosquitoes, indicating similar initial behaviors when nearing the nets.
- However, resistant mosquitoes tended to stay farther away from the treated nets, and the nets that were effective in laboratory settings caused less mortality when tested in the wind tunnel, suggesting the need for improved methods to assess the effectiveness of insecticidal nets.
Article Synopsis
- Female mosquitoes, specifically Anopheles gambiae, rely on human odor and heat to navigate towards their blood hosts, exhibiting unique flight behaviors under different stimuli conditions.* -
- In experiments, wind alone resulted in straight flight paths, while human odor caused more complex and longer flight patterns; combining odor with heat intensified these effects, leading to higher flight speeds and increased landings.* -
- Understanding these flight behaviors can enhance mosquito trapping systems by optimizing odor release locations and incorporating heat sources to improve effectiveness in capturing malaria-carrying mosquitoes.*
Article Synopsis
- Many parasites, like the baculovirus AcMNPV, can change the behavior of their hosts, which in this case are Spodoptera exigua larvae, to help spread themselves.
- Researchers found that the virus causes hyperactive behavior in the larvae, and identified a specific viral protein, the ptp gene, as crucial for this effect.
- Their findings suggest that this manipulation is not just a one-off but an evolutionarily conserved tactic among similar viruses, providing insights into how these viruses influence insect behavior.
Article Synopsis
- The study examines the effectiveness of carbon dioxide (CO2) produced by fermenting yeast as an alternative to industrial CO2 in attracting the malaria-carrying mosquito species Anopheles gambiae in various trapping setups.
- Experiments showed that traps using yeast-produced CO2 attracted significantly more mosquitoes than unbaited traps and even more than traps using industrial CO2, particularly when paired with human odors.
- Implementing traps with yeast-produced CO2 reduced the number of mosquitoes entering homes, suggesting a practical application for controlling mosquito populations in areas prone to malaria.
Article Synopsis
- A study in The Netherlands examined how large herbivores (cattle) affect the number of Ixodes ricinus ticks and their Borrelia infections in woodland areas with oak and pine trees, either grazed or ungrazed.
- The findings showed that ungrazed woodlands had significantly more ticks, with higher Borrelia infection rates in nymphs found in oak compared to pine habitats.
- The presence of cattle reduced the tick population and rodent density, but did not influence Borrelia infections, suggesting potential management strategies for woodland reserves and Lyme disease risks.
Article Synopsis
- - The study examined how chemical cues, specifically human and synthetic odor blends, affect blood-feeding mosquitoes' attraction in The Gambia using various traps.
- - MM-X traps were tested with a range of odor blends, including mixtures with and without carbon dioxide (CO2), revealing that synthetic odors often lured more mosquitoes than human odors.
- - The most successful odor blend contained ammonia, L-lactic acid, and CO2, significantly increasing mosquito attraction and suggesting better methods for mosquito surveillance and control.