Device and method for the spatial control of insects

Abstract

The invention relates to a repellent device the spatial control of disease vectors such as mosquitoes, which utilises a combination of powered airflow and centrifugal force to efficiently vaporize and discharge active VOCs into the air. A kit of parts of preparing said device and methods for controlling insects by discharging active VOCs into the air are also provided.

Description

[0001] Device and Method for the Spatial Control of Insects

[0002] The present invention relates to an active, i.e. powered, spatial insect control device and methods for controlling or repelling insects, in particular disease vectors such as mosquitoes, via the use of such a device, wherein said device functions by vaporizing and discharging insecticidal and / or insect repellent volatile organic compounds (VOCs) into the air.

[0003] Background of the Invention

[0004] Mosquito-borne diseases (including malaria, dengue fever, chikungunya, Zika, Japanese encephalitis, West Nile and yellow fever) remain major killers worldwide and their associated treatment costs and morbidity affect work, schooling and adversely affects productivity and learning, contributing to continuing poverty.

[0005] Over 240 million cases of malaria occur each year resulting in over 600,000 deaths (in 2021 ). From about 1995 to 2015, malaria cases halved mainly due to three widespread interventions: Insecticide Treated bed-Nets (ITN’s); Indoor Residual Spraying (IRS) and Intermittent Preventative Treatment (IPT). Over 95% of infections and deaths from malaria occur in Sub-Saharan Africa.

[0006] Active mains powered spatial vector-control dispensers are commonly used in urban areas. These use heat to evaporate an insecticide dissolved in a light oil. Two variants are common either heating a small pad soaked in the chemical or using a heated wick to draw the chemicals from a glass refill bottle. Drawing only 3-5W of power, the units are inexpensive to operate, and provide excellent prophylactic prevention against mosquito bites in rooms. They are also designed or sold as general insecticides protecting against a variety of insects especially those which bite humans. They thus can protect against a variety of insect-borne diseases depending on the targeted species, the chemicals used, and the spatial concentrations of active chemicals achieved in normal or intended use.

[0007] However, about 80% of sub-Saharan Africans live in rural areas. Of these, less than 70% have any access to electricity and grid extension to these villages and dwelling remains prohibitively expensive. A fast-growing method of off-grid electrification is via Solar Home Systems (SHSs) providing light, cell phone charging, radios, TV (in larger systems) etc. The smallest common systems use 20W solar panels, and will typically power 4 high-efficiency LED bulbs. Although an inverter could be used to power a mains-powered active vector-control dispenser, the use of such a device overnight would use up all the power in such a SHS system.

[0008] This invention seeks, therefore, to significantly reduce the power consumption of an active spatial vector-control dispenser (by a factor of 20-100) making it possible to be used with SHSs or a very small (~5W) dedicated solar panel and this provide a new cost-effective malaria prevention intervention to be used alongside or to displace current interventions in off-grid settings. A key consideration in the design of any such device is to ensure that the concentrations of the active chemical in a room environment attain high enough levels to be sufficiently efficacious, whilst remaining well below any levels likely to cause harm to humans. All this has to be carried out by a device which is both low cost to purchase and operate (i.e. with low-cost refills) and can be powered by a small inexpensive solar panel.

[0009] A further emerging problem in the prevention and treatment of malaria is the emergence of mosquito resistance to insecticides, potentially reducing the effectiveness or rendering ineffective some or all of the current interventions in the years to come. It is an object of the invention to incorporate adaptations to insect repellent methods and active spatial repellent devices to slow, reduce or prevent the onset of insecticide resistance in mosquito and / or other disease vectors which could otherwise reduce the future efficacy of such devices.

[0010] Different forms of resistance are reported in the literature:

[0011] 1. Behavioural whereby mosquitoes change their behaviours (by selection). Examples might be feeding more or less on animals vs humans; changing feeding times to early evening when humans are not protected under bed nets;

[0012] 2. Target site insensitivity, where a mutation in the insecticide target site renders it less susceptible to its action;

[0013] 3. Reduced penetration, where changes to the cuticle can prevent access of the insecticide to the target site; 4. Metabolic, whereby the mosquitoes build resistance to the insecticide through changes in or upregulation of the enzymes that degrade them;

[0014] Anticipating the possible failure of current control tools due to resistance, new types of bed nets and new insecticides have been developed. For example, researchers from LSHTM have tested a ‘resistance breaking’ mosquito net for its efficacy in a trial involving 15,000 children in Tanzania. As a direct consequence of the trial, WHO revised its recommendations on bed nets in September 2017, giving an interim policy recommendation to piperonyl butoxide (PBO) bed nets as a new class of bed nets1. These bed nets used permethrin as the active ingredient but also incorporated a second chemical - PBO, a chemical that inhibits the oxidase enzymes that would otherwise metabolise the insecticide in resistant strains. This means the pyrethroid on the bed net remains potent against mosquitoes and remains effective in reducing malaria in areas where this mechanism of resistance is prevalent.

[0015] Although this description primarily discusses malaria as the disease of initial impact and mosquito control in more general terms, the invention may also be applicable to the control of mosquito species that transmit pathogens causing other diseases, or indeed to the control of other insects in general, including where the biting of the insects does not carry significant disease risk, but where the insects and their bites are a nuisance.

[0016] We herein disclose an alternative, active spatial insect-control device that is particularly suitable for use in off-grid (rural settings), to reduce or prevent insect bites, especially mosquito bites, and hence help to reduce the burden and impact of mosquito-borne diseases.

[0017] It is a further objective of the invention to future proof active spatial insect control devices and methods for controlling or repelling insects, in particular disease vectors such as mosquitoes, by providing adaptations that incorporate mechanisms to prevent or restrict the emergence of resistance.

[0018] 1https: / / www.lshtm.ac.uk / newsevents / news / 2019 / resistance-breaking-mosquito-net-provides-children-greater-protection-against Statements of Invention

[0019] The present invention, in its various aspects, is as set out in the accompanying claims.

[0020] According to a first aspect of the invention an active spatial insect vector control (repellent) device is provided that incorporates a high efficiency motor-powered fan into a small, palm-sized casing and a source of active VOC compounds.

[0021] In particular, the invention provides an insect control device, said device comprising: a. a chambered structure comprising at least one vent configured to permit airflow between the interior and exterior of said chambered structure; b. a rotatable fan disposed within said chambered structure; c. a volatile organic chemical (VOC) retainer disposed within said chambered structure in a position between said at least one vent and said fan; d. a rotational drive part connected to and configured to rotate, independently or concurrently, said VOC retainer and said fan; e. a power source configured to provide power to said rotational drive part; and, optionally, f. control electronics configured to control the timing and / or speed of rotation of said rotational drive part, said VOC retainer and said fan, wherein said VOC retainer comprises, or is configured to contain, an insect repellent or insecticidal composition comprising one or more active VOC compounds, and wherein the size of the VOC retainer and the rotational speed of the rotational drive part are selected such that, upon controlled rotation of said rotational drive part, said VOC retainer is subject to relative centrifugal force (RCF) of from about 25 g to about 75 g, and preferably from about 40 g to about 60 g.

[0022] As used herein, and as would be readily understood by the skilled reader, the term ‘active VOC compound’ refers to any volatile organic chemical that, at concentrations deliverable by the device of the invention, has an adverse impact on insects, in particular disease vectors such as mosquitoes, in terms of their ability to land on and / or bite a human subject. The active chemical could for example be an insecticide increasing the mortality or morbidity of the insect, or it could be an insect repellent. As used herein, the term ‘relative centrifugal force’ is an index that indicates the strength of the centrifugal force exerted on the rotating VOC retainer, and has a numerical value represented by

[0023] RCF (g) = 1.18x10'5x r x s2wherein r represents the radius of the rotating VOC retainer (cm), and s is the speed of revolution (revolutions per minute).

[0024] Advantageously, the present invention provides a device in which the efficiency of vaporization and discharging of active VOC(s) is increased by enhancing airflow by the combined rotation of the VOC retainer and associated fan. Specifically, controlling rotation of the VOC retainer such that it is subject to relative centrifugal force (RCF) of from about 25 g to about 75 g, and preferably from about 40 g to about 60 g enables concentrations of the active VOCs in a room environment to attain high enough levels (> about 1.5 ng / litre) to be sufficiently efficacious, whilst remaining well below any levels likely to cause harm to humans and whilst drawing a very low power (< about 0.5 W, and preferably < about 0.2 W). Therefore, the device is suitable for use in conjunction with small Solar Home Systems or lanterns or a small- low-cost (dedicated) solar panel.

[0025] For example, the device of the present invention is preferably capable of discharging a sufficient quantity of said one or more insect repellent or insecticidal VOC (e.g. transfluthrin) into the air such that, after 60 minutes of continuous operation in a closed room of approximately 55 cubic meters, the concentration of said insect repellent or insecticidal VOC(s), measured at a distance of 2 metres from the device, is at least about 1 .5 ng / l, preferably at least about 3 ng / l, and most preferably at least about 6 ng / l. Likewise, other VOCs can be discharged into the air at a concentration at or above the air concentration that correlates to a greater than 90 percent reduction in biting in a free-flight room clinical trial or any other concentrations as set by the WHO recommendations (e.g. as proposed or recommended by the Vector- Control Advisory Group VCAG working under the auspices of the WHO). In preferred examples, the device disperses active VOC(s) in an amount such that the air concentration, measured at a distance of 2 metres from the device in a closed room of approximately 55 cubic meters, reaches at least double the concentration needed to achieve a 90% reduction in biting. Preferably, the device is a mosquito control device. As used herein, the term “mosquito” refers to an insect which is a member of the family Culicidae. This includes the subfamilies Anophelinae and Culicinae', and thereby species of the genera Aedeomyia, Aedes, Anopheles, Armigeres, Ayurakitia, Borachinda, Coquillettidia, Culex, Culiseta, Deinocerites, Eretmapodites, Ficalbia, Galindomyia, Haemagogus, Heizmannia, Hodgesia, Isostomyia, Johnbelkinia, Kimia, Limatus, Lutzia, Malaya, Mansonia, Maorigoeldia, Mimomyia, Onirion, Opifex, Orthopodomyia, Psorophora, Runchomyia, Sabethes, Shannoniana, Topomyia, Toxorhynchites or Trichoprosopon.

[0026] In preferred embodiments, the device comprises at least one vent that is moveable between a first or open position that permits airflow between the interior and exterior of said chambered structure, and a second or closed position that prevents or restricts airflow between the interior and exterior of said chambered structure. In particularly preferred embodiments, the device is configured such that the rotational drive part is switched on, and so rotation of the VOC retainer and fan commences, upon moving the said at least one vent into the first or open position.

[0027] In preferred embodiments the interior of the chambered structure comprises vanes or airflow passages that are configured to provide increased air flow speed in or around said VOC retainer upon rotation of said rotational drive part. Such an arrangement advantageously increases the efficiency of VOC release to the air.

[0028] Preferably, the device comprises a chambered structure formed from at least two releasably engageable outer parts. These can be separated to gain access to the inside of the chambered structure in order to, e.g., replace or refill the VOC retainer.

[0029] In a preferred arrangement, the VOC retainer is releasably connected to said rotational drive part via a mounting point so as to permit removal from, and replacement within, said chambered structure. This enables the removal and replacement of the VOC retainer at the end of its useful life.

[0030] In some embodiments, the VOC retainer is in the form of a simple fluid reservoir or receptacle. Alternatively, the VOC retainer is in the form of an absorbent disc so that the insect repellent or insecticidal composition is held in place by surface tension, or a form of physical or chemical sorption. In such embodiments, the absorbent disc is preferably formed from one or more biodegradable materials, in particular biodegradable fibrous materials including but not limited to cotton, bamboo or other plant or animal-based fibre, for ease of recycling.

[0031] However, in order to give structure to the absorbent disc, it may further comprise one or more (non-biodegradable) plastic fibres. However, in such embodiments, said plastic fibres are preferably present in an amount less than about 50%, more preferably less than about 30%, more preferably less than about 15%, and still more preferably less than about 10% of the (dry) weight of said absorbent disc. For the avoidance of doubt, the (dry) weight refers total weight of the absorbent disc prior to the addition of any insect repellent or insecticidal compositions comprising one or more active VOC compounds.

[0032] In particularly preferred embodiments, the absorbent disc is composed entirely of biodegradable fibrous materials. Further, the disc is preferably manufactured in a way that does not impair the natural decomposition of disc at the end of its usable life. The disc may be uniform in section to simplify manufacture or it may have structures, ribbing, different thicknesses or additional holes to enhance, optimise and / or otherwise control VOC release. Alternatively or additionally, the surface to volume thickness may be optimised to maintain a relatively constant concentration of VOC(s) released into the surrounding air, whilst ensuring that the disc continues to discharge insect repellent or insecticidal VOCs into the air during multiple nights of use, preferably at least 7 days, more preferably at least 14 days, still more preferably at least 1 month and more preferably at least 3 months.

[0033] Preferably, the VOC retainer has a diameter of from about 20mm to about 30mm, and preferably from about 22 mm to about 28 mm and / or the rotational drive part is configured to rotate the VOC retainer at a speed of from about 500 rpm to about 5000 rpm, and preferably from about 1000 rpm to about 2000 rpm. Alternatively or additionally, the VOC retainer preferably has a depth of from about 1 mm to about 20 mm, and more preferably from about 2 mm to about 10 mm. In an exemplary example, the VOC retainer has a diameter of about 27 mm and a depth of about 5 mm.

[0034] In preferred embodiments, the VOC retainer comprises an insect repellent or insecticidal composition comprising one or more active VOC compounds selected from botanical extracts and / or pyrethroid compounds. Preferably, said pyrethroid compounds are selected from: permethrin; transfluthrin; metafluthrin; allethrin, e.g. D-Cis / Trans allethrin; prallethrin, e.g. 1 R-trans prallethrin; meperfluthrin; and combinations thereof. Preferred botanical extracts are selected from: citronella; cassia; cedar; lavender; eucalyptus; neem tree oil; and combinations thereof.

[0035] In particularly preferred embodiments, the insect repellent composition comprises one or more VOC compounds that are pyrethroid compounds, and in one such preferred embodiment, the insect repellent composition comprises two or more, and more preferably three or more, pyrethroid compounds, wherein said pyrethroid compounds are preferably selected from metafluthrin, D-cis / trans allethrin, and 1 R- trans pralletrhin.

[0036] In alternative exemplary embodiments, the insect repellent composition comprises transfluthrin.

[0037] In some embodiments, the insect repellent or insecticidal composition further comprises one or more insecticidal synergist or effector compounds. As the skilled person will readily appreciate, such compounds do not possess any significant insecticidal or insect repellent activity, but upon combination, increase the effectiveness of insect repellent or insecticidal active VOC compounds such as pyrethrins and / or maintain insecticidal or insect repellent activity of such VOC compounds by inhibiting one or more resistance pathways from developing. Preferred synergist compounds are selected from piperonyl butoxide (PBO), piperonyl sulfoxide, sesamex, S,S,S,-tributylphosphorotrithioate (DEF), diethyl maleate (DEM), triphenyl phosphate (TPP), verapamil, ethacrinic acid and combinations thereof, with PBO being particularly preferred.

[0038] In particularly preferred embodiments, the device is configured to work with multiple different repellent or insecticidal compositions. For example multiple different VOC retainers may be provided, each containing a different active VOC and / or a different synergist or effective compound. The device may be configured to automatically recognise the different characteristics of each VOC retainer (e.g. by association with a distinguishing feature such as a colour; size; shape, or notch) and set the physical parameters (e.g. fan speed and VOC retainer speed speed) accordingly. Alternatively, the device may include a manual switch to switch between settings. In such embodiments, the device can be used to disperse one particular active VOC compound (or group of compounds) throughout one particular area, community, district, region or country until such time that an early onset of resistance to said VOC compound(s) is noted. Then the device can be used to disperse a different VOC compound (or group of compounds) to retain the insect control effect whilst preventing or substantially delaying the build-up of significant resistance. Such a sequential multi-chemical strategy has been shown to significantly delay the onset of and impact of mosquito resistance2, particularly if the resistance mechanism is different for each chemical.

[0039] Resistance may also be countered using a dispenser that emanates two active ingredients at the same time I in parallel. In particular a single VOC retainer may be configured to comprise or contain an insecticidal or insect repellent VOC and a second chemical, for example, a synergist or effector compound such as PBO, which will inhibit the oxidase enzymes that would otherwise metabolise the insecticide in resistant strains.

[0040] Therefore, in preferred embodiments, the VOC retainer comprises, or is configured to contain, a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound.

[0041] In said embodiments, the VOC retainer is preferably segmented into a plurality of physically discrete sections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

[0042] As the device is cable of providing a high spatial concentration (> about 1.5ng / litre) of active material in the surrounding area whilst drawing a very low power (< about 0.2W), it preferably comprises a battery as the power source. In particularly preferred embodiments, the power source is a rechargeable battery, and the device may further comprise, or is configured to connect to, a charging device such as a mains or solar powered charging device. The use of a rechargeable battery is critical to reducing waste and cost from otherwise replaceable batteries (cells). It is preferable that the power drawn by the motor to provide an efficacious concentration of active chemical is less than 0.5 W, or less than 0.2 W or less than 0.1 W or less than 0.05 W averaged over the chosen duty cycle of operation. In such embodiments, the device may further comprise a charging port, which is preferably provided as a standardised socket and charging specification such as those used on mobile phones, including but not limited to LISB-A; micro-USB; USB C. The correct recharging voltage and current can then be supplied by suitable outlets from multiple charging devices including: a mains powered charger; a Solar Home System; or a small solar panel.

[0043] The device preferably further comprises control electronics that are configured to control the timing and / or speed of rotation of the rotational drive part, the VOC retainer and said fan. The control electronics can, in preferred embodiments, also set the duty cycle, i.e. how long the system operates in a set period of time. It is anticipated that the device will be operated for around 14 hours each night to provide good protection when malaria mosquitoes are particularly active, or potentially up to 24 hours a day to provide protection against the lesser residual daytime biting and / or to provide protection against mosquito species which are more active during daylight and dusk hours.

[0044] As will be readily appreciated, the VOC retainer can be provided separately to the remainder of the device. Said VOC retainers can be provided as individual or multiple entities, and are preferably provided in individual pre-sealed containers to prevent premature evaporation of the VOC compounds.

[0045] Therefore, according to a second aspect, the invention provides a kit of parts suitable for preparing the insect control device according to the first aspect, wherein said kit comprises: i) one or more volatile organic chemical (VOC) retainers; and ii) a housing comprising: i. a chambered structure comprising at least one vent configured to permit airflow between the interior and exterior of said chambered structure; ii. a rotatable fan disposed within said chambered structure; iii. a mounting point configured to removably secure one of said one or more VOC retainer within said chambered structure in a position between said at least one vent and said fan; iv. a rotational drive part connected to and / or configured to rotate, independently or concurrently, said fan and, when placed in said mounting point, said VOC retainer; v. a power source configured to provide power to said rotational drive part; and, optionally, vi. control electronics configured to control the timing and / or speed of rotation of said rotational drive part, said VOC retainer and said fan, wherein each of said one or more VOC retainer comprises, or is configured to contain, an insect repellent or insecticidal composition comprising one or more active VOC compounds, and wherein the size of the VOC retainer and the rotational speed of the rotational drive part are selected such that, upon controlled rotation of said rotational drive part, said VOC retainer is subject to relative centrifugal force (RCF) of from about 25 g to about 75 g, and optionally from about 40 g to about 60 g.

[0046] Preferably, said kit comprises a plurality of said VOC retainers, wherein each of said plurality of VOC retainers optionally comprises or is configured to contain a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound and / or multiple combinations thereof.

[0047] In one such embodiment, each of said plurality of VOC containers is segmented into a plurality of physically discrete sections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

[0048] According to a third aspect, the invention provides a method of controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing the device according to the first aspect if the invention; b. rotating said rotational drive part, said VOC retainer and said fan, wherein said VOC retainer is rotated at a speed such that it is subject to a relative centrifugal force (RCF) of from about 25 g to about 75 g and optionally from about 40 g to about 60 g; and, optionally, c. refilling said VOC retainer with said insect repellent or insecticidal composition, or alternatively replacing said VOC retainer with a second VOC retainer in said chambered structure, before repeating step b.

[0049] According to a fourth aspect, the invention provides a method for controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing the kit of parts according to the second aspect of the invention, and inserting a first VOC retainer into the mounting point of said housing; b. rotating said rotational drive part, said first VOC retainer and said fan, wherein said first VOC retainer is rotated at a speed such that it is subject to a relative centrifugal force (RCF) of from about 25 g to about 75 g and optionally from about 40 g to about 60 g; and, optionally, c. refilling said first VOC retainer with said insect repellent or insecticidal composition, or alternatively replacing said first VOC retainer with a second VOC retainer on said mounting point, before repeating step b.

[0050] Further, it will be appreciated that the benefits, in particular relating to reducing the onset of resistance, associated with the use of multiple different repellent or insecticidal compositions is not limited to the use of the specific, improved device as disclosed above, but would be equally applicable to any other active spatial insect control device.

[0051] Therefore, according to a fifth aspect, the invention provides an insect control device, said device comprising: a. a volatile organic chemical (VOC) retainer; b. an active VOC disperser; c. a power source configured to provide power to said VOC disperser; and, optionally, d. control electronics configured to control the actuation of said VOC dispenser and / or control the discharge of VOCs from said device, wherein said VOC retainer comprises, or is configured to contain, a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound, and wherein said VOC retainer is optionally segmented into a plurality of physically discrete sections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

[0052] Similarly, according to a sixth aspect, the invention provides a method for controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing an insect control device, said device comprising: a. a removable, replaceable and / or refillable first volatile organic chemical (VOC) retainer, wherein said VOC retainer comprises, or is configured to contain, a first insect repellent or insecticidal composition comprising one or more active VOC compounds; b. an active VOC disperser; c. a power source configured to provide power to said VOC disperser; and, optionally, d. control electronics configured to control the actuation of said VOC dispenser and / or control the discharge of VOCs from said device, b. actuating said VOC disperser to discharge said one or more active VOC compounds from said first insect repellent or insecticidal composition into the environment; c. refilling said first VOC retainer with a second insect repellent or insecticidal composition, or alternatively replacing said first VOC retainer with a second VOC retainer comprising said second insect repellent or insecticidal composition; and d. actuating said VOC disperser to discharge said one or more active VOC compounds from said second insect repellent or insecticidal composition into the environment, wherein said first and said second insect repellent or insecticidal compositions comprise a different active VOC compound and / or a different synergist or effector compound. In both the fifth and the sixth aspects, the active VOC dispenser preferably comprises or consists of a heating element and / or a fan.

[0053] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprises”, mean “including but not limited to” and do not exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Throughout the description and claims of this specification, the word “about” means ± 5 %, alternatively ± 2 % unless the context otherwise requires.

[0054] As used herein, and would be readily appreciated by the skilled reader, the terms “disc” and “coin”, as used in in the context of the VOC retainer, are interchangeable, and refer to any structure of generally circular and relatively flat configuration, and includes structures of varying thickness and / or a perimeter that, while following a generally circular path, may also be comprised of one or more straight or curved segments. Further, the structure may contain at least one through hole and / or indentation, which may be located on or remote from the axis of rotation.

[0055] As used herein, and would be readily understood by the skilled reader, the term “control electronics” refers to any means for actuating the associated component, e.g. a VOC disperser such as a fan or heating element, rotational drive part, VOC retainer. Therefore, a simple on-off type switch and / or more complex electronic control circuitry (configured to control, e.g., duty cycle) are including within the scope of such a term.

[0056] All references, including any patent or patent application, cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. Further, no admission is made that any of the prior art constitutes part of the common general knowledge in the art.

[0057] Preferred features of each aspect of the invention may be as described in connection with any of the other aspects.

[0058] Other features of the present invention will become apparent from the following examples. Generally speaking, the invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including the accompanying claims and drawings). Thus, features, integers, characteristics, compounds or chemical moieties described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein, unless incompatible therewith.

[0059] Moreover, unless stated otherwise, any feature disclosed herein may be replaced by an alternative feature serving the same or a similar purpose.

[0060] A representative example of the insect control device according to the first aspect of the invention will now be described, by way of example only, with reference to the following figures wherein:-

[0061] Figure-1 shows a perspective view of a configuration of the insect control device according to a first embodiment of the present invention;

[0062] Figure-2 shows a partially explode perspective view of the embodiment of Figure 1 ;

[0063] Figure-3 shows plan and elevation views of the VOC retainer, provided the form of a biodegradable absorbent disc, of the embodiment of Figure 1 ;

[0064] Figure-4 shows a plan view of the embodiment of Figure 1 , with the VOC retainer in place and secured under a removable lid;

[0065] Figure-5 provides schematic diagrams of the removable lid of the embodiment of Figure-1 ;

[0066] Figure-6 shows a plan view of the rotatable fan of the embodiment of Figure 1 ;

[0067] Figure-7 shows multiple schematic views of the inner vent housing of the upper casing of the embodiment of Figure 1 ;

[0068] Figure-8 shows multiple schematic views of the outer vent housing of the upper casing of the embodiment of Figure 1 ;

[0069] Figure-9 shows the plan and elevation views of the rotational drive part, specifically a motor, of the embodiment of Figure 1 ; and

[0070] Figure-10 shows multiple schematic views of the bottom housing of the embodiment of Figure 1 . Description of the first embodiment

[0071] CONFIGURATION

[0072] Referring to Figure 1 , an insect control device forms a chambered structure via the releasable connection of a bottom housing 10, middle housing 4 and an upper, vented, housing formed from engagement of vent inner 5 and vent outer 9. Rotation of the vent inner 4 with respect to vent outer 9 serves to move said vents from a first or open position that permits airflow between the interior and exterior of said chambered structure, and a second or closed position that prevents or restricts airflow between the interior and exterior of said chambered structure. In preferred embodiments, moving said vents to an open position also acts as a switch to deliver power to a motor disposed inside the chambered structure. A removable vented lid is provided at the top of the device, under which a VOC retainer, which in this embodiment is an absorbent biodegradable (cotton and polyester) disc dosed with a composition comprising transfluthrin (active agent), light paraffin oil (stabilizer) and butylated hydroxytoluene (stabilizer), is housed (Figure 2).

[0073] As best shown in Figures 2 and Figure 3, the biodegradable disc is a substantially flat circular or coin shape, having a thickness of about 5 mm and a diameter of about 27 mm, and three small holes (one in the centre on two on the periphery of the coin) through which the coin connects directly to a mounting structure disposed on the upper surface of the fan located in the core of the device. The use of such mounting points to hold the coin in place above the fan ensures that the fan and coin will spin concurrently, with such rotation providing a dual effect of increasing airflow and centrifugal force applied to coin to facilitate evaporation the active VOC compound(s). In addition, and as clearly shown in Figures 4 and 5, the removable vented lid comprises a series of apertures that serve to further increase air flow through said coin and into the fan area.

[0074] The coin mounting arrangement provided on the integral powered fan is best shown in Figure 6, wherein the fan is provided with a central aperture through which the rotational drive part passes to and connects to said fan and coin, and two spikes that are configured to engage with and hold, and so rotate, the coin concurrently with rotation of the fan. As shown in Figures 9 and 10, a circular power source or brushless motor, which is configured to fit within the interior of said bottom housing, is connected to and configured to concurrently rotate the fan and VOC containing coin. The fan motor specifically has a motor life of 10,000 hr (to achieve a minimum 2 year product lifespan using 12 hour duty cycle) and derives its power from a 102 hour runtime rechargeable Li-ion battery with a working current of 59mAh.

[0075] The external surfaces of the device also house a battery status indicator light (e.g. red - working, green flashing - low battery <20%, green - charging) and / or a micro USB port or similar (not shown) to connect to a battery charging circuit.

[0076] EXAMPLE 1: VOC Release Tests

[0077] Previous tests undertaken at London School of Hygiene & Tropical Medicine have shown that a concentration of 1.65 ng / litre of transfluthrin in air had a mosquito repellent efficacy of over 90%. Therefore, 1 .65 ng / litre transfluthrin was considered to be the minimum target transfluthrin level (TTL) for a highly efficacious device

[0078] However, the testing of several active spatial dispenser designs analogous to that of the present invention but in which the transfluthrin dosed coin was not concurrently rotated with said fan to develop an appreciable relative centrifugal force and / or commensurate airflow, did not approach such a TTL value, instead providing transfluthrin output levels in the range of 0.56 ng / l (~3x below target) to 0.073 ng / l (~22x below target).

[0079] In contrast, upon directly mounting a 5mm x 27 mm coin directly on to a fan, the combination of enhanced airflow and centrifugal force (1425 rpm rotation, 1.25 cm radius; approx. 50 g) clearly facilitated movement and thus evaporation of the VOC chemical, resulted in a dramatic increase of transfluthrin release, achieving an average in air concentration of 6.05 ng / l, i.e. more than 3.5 x TTL.

[0080] EXAMPLE 2: Spatial Repellence Efficacy Tests

[0081] As a proof of concept, small scale repellence tests were conducted using the transfluthrin-containing device prepared according to Example 1 . MATERIALS AND METHODS

[0082] INSECTS

[0083] Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus mosquitoes were obtained from insecticide-susceptible reference strains. All mosquitoes were reared and housed under optimal environmental conditions of 27°C ±2°C and 75% ±10% Relative Humidity with a 12:12 hour photoperiod. The mosquitoes were host-seeking females of uniform age (2-7 days post-emergence) having never had a blood meal.

[0084] TESTING PROCEDURE (HUMAN LANDING CATCH)

[0085] Nine replicates were conducted in total, which consisted of a control and a treatment rep. Eight of the replicates were performed with Anopheles mosquitoes and one was performed with Culex mosquitoes.

[0086] CONTROL TEST

[0087] 1 . Participant sits in the pest pod test chamber on the stool with an aspirator and pre-set timer.

[0088] 2. 50 mosquitoes are released into the release chamber.

[0089] 3. Participant collects the mosquitoes which have landed on their exposed forearms I legs over a period of 15 minutes.

[0090] 4. After the 15 minutes, the participant shuts the joining door and collects the rest of mosquitoes which have entered the test chamber.

[0091] 5. The participant then collects the remaining mosquitoes that have remained in the release chamber.

[0092] 6. The number of mosquitoes collected in each cup (landed, test and release) are recorded.

[0093] TREATMENT TEST

[0094] 1. The powered spatial repellent device of Example 1 is switched on in the test chamber Coining doors between the chambers shut) and left to run for 1 hour before testing. 2. Participant sits in the test chamber on the stool with the aspirator and pre-set timer.

[0095] 3. 50 mosquitoes are released into the release chamber.

[0096] 4. Participant collects the mosquitoes which have landed on their exposed forearms I legs over a period of 15 minutes.

[0097] 5. After the 15 minutes, the participant shuts the joining door and collects the rest of mosquitoes which have entered the test chamber.

[0098] 6. The participant then collects the remaining mosquitoes that have remained in the release chamber.

[0099] 7. The number of mosquitoes collected in each cup (landed, test and release) are recorded.

[0100] The protective efficacy (PE) was determined by: where Cf is the number of mosquitoes landing / feeding on the participant during testing the control device and Tf is the number of mosquitoes landing / feeding on the participant during the testing of the powered spatial repellent device.

[0101] Vector entry inhibition is determined by: where Cl is the number of mosquitoes in the test chamber following testing of the control device and Tl is the number of mosquitoes in the test chamber following testing with the powered spatial repellent device.

[0102] RESULTS

[0103] HUMAN LANDING CATCH

[0104] Anopheles

[0105] 8 / 9 reps conducted with Anopheles

[0106] Mean Protective Efficacy: 92%

[0107] Entry Inhibition: 10%

[0108] Culex

[0109] 1 / 9 reps conducted with Culex

[0110] Protective Efficacy: 18%

[0111] Entry Inhibition: -15%

[0112] OBSERVA TIONS

[0113] A high protective efficacy was seen and there was a visible knock down effect to the mosquitoes exposed to the transfluthrin. In the treatment replicates, mosquito landing I biting was skewed to the mosquitoes that were better at host seeking and, therefore, reached the participant quickly after entering the test chamber before becoming knocked down. Mosquitoes that were slower to host seek were knocked down before landing on the participant. While the protective efficacy was high, there was a low number of mosquitoes landing in both the control and treatment replicates (< 10 each time) and therefore results may need to be adjusted for this. Potential reasons for the poor host seeking behaviour of the mosquitoes could include colony fitness, age of mosquitoes, attractiveness of the host etc.

[0114] Low entry inhibition was observed. Mosquitoes did not appear to be prevented from entering the space where the participant was sitting, but once inside the mosquitoes were knocked down.

[0115] From the limited testing with Culex, these mosquitoes appeared to be less impacted by the transfluthrin than the Anopheles mosquitoes.

Claims

Claims1 . An insect control device, said device comprising: a. a chambered structure comprising at least one vent configured to permit airflow between the interior and exterior of said chambered structure; b. a rotatable fan disposed within said chambered structure; c. a volatile organic chemical (VOC) retainer disposed within said chambered structure in a position between said at least one vent and said fan; d. a rotational drive part connected to and configured to rotate, independently or concurrently, said VOC retainer and said fan; e. a power source configured to provide power to said rotational drive part; and, optionally, f. control electronics configured to control the timing and / or speed of rotation of said rotational drive part, said VOC retainer and said fan, wherein said VOC retainer comprises, or is configured to contain, an insect repellent or insecticidal composition comprising one or more active VOC compounds, and wherein the size of the VOC retainer and the rotational speed of the rotational drive part are selected such that, upon controlled rotation of said rotational drive part, said VOC retainer is subject to relative centrifugal force (RCF) of from about 25 g to about 75 g.

2. The device according to claim 1 , wherein said insect is a mosquito.

3. The device according to claim 1 or claim 2, wherein: said at least one vent is moveable between a first or open position that permits airflow between the interior and exterior of said chambered structure, and a second or closed position that prevents or restricts airflow between the interior and exterior of said chambered structure; and wherein the device is optionally configured such that the rotational drive part is switched on, and so rotation of the VOCretainer and fan commences, upon moving said at least one vent into the first or open position.

4. The device according to any one of the preceding claims, wherein the interior of said chambered structure comprises vanes or airflow passages configured to provide increased air flow speed in or around said VOC retainer upon rotation of said rotational drive part.

5. The device according to any of the preceding claims, wherein said chambered structure comprises at least two releasably engageable outer parts.

6. The device according to any one of the preceding claims, wherein said VOC retainer is releasably connected to said rotational drive part via a mounting point so as to permit removal from, and replacement within, said chambered structure.

7. The device according to any one of the preceding claims, wherein said VOC retainer is in the form of a fluid reservoir.

8. The device according to any one of claims 1 to 6, wherein said VOC retainer is in the form of an absorbent disc, and wherein said absorbent disc is optionally formed from one or more biodegradable and / or fibrous materials such as cotton, bamboo or other plant or animal-based fibre.

9. The device according to claim 8, wherein said disc further comprises one or more plastic fibres, and wherein said plastic fibres are optionally present in an amount less than about 50% of the (dry) weight of said disc.

10. The device according to any of the preceding clams, wherein said VOC retainer has a diameter of from about 20mm to about 30mm, and / or a depth of from about 1 mm to about 20 mm, and / or wherein the rotational drive part isconfigured to rotate said VOC retainer at a speed of from about 500 rpm to about 5000 rpm.

11. The device according to any of the preceding claims, wherein said one or more active VOC compounds are selected from botanical extracts and / or pyrethroid compounds, wherein said pyrethroid compounds are optionally selected from: permethrin; transfluthrin; metafluthrin; allethrin e.g. D-Cis / Trans allethrin; prallethrin, e.g. 1 R-trans prallethrin; meperfluthrin; and combinations thereof, and wherein said botanical extract is selected from: citronella; cassia; cedar; lavender; eucalyptus; neem tree oil; and combinations thereof.

12. The device according to any of the preceding claims, wherein said insect repellent or insecticidal composition further comprises, or is configured to further contain, one or more insecticidal synergist or effector compounds, and wherein said synergist or effector compound is optionally selected from piperonyl butoxide, piperonyl sulfoxide, sesamex, S,S,S,- tributylphosphorotrithioate, diethyl maleate, triphenyl phosphate, verapamil, ethacrinic acid and combinations thereof.

13. The device according to any of the preceding claims, wherein said VOC retainer comprises, or is configured to contain, a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound.

14. The device according to claim 13, wherein said VOC retainer is segmented into a plurality of physically discrete sections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

15. The device according to any one of the preceding claims, wherein said power source is a battery, preferably a rechargeable battery.

16. The device according to claim 15, wherein said device further comprises, or is configured to connect to, a charging device such as a mains or solar powered charging device.

17. A kit of parts suitable for preparing the insect control device according to any one of the preceding claims, wherein said kit comprises: i) one or more volatile organic chemical (VOC) retainers; and ii) a housing comprising: i. a chambered structure comprising at least one vent configured to permit airflow between the interior and exterior of said chambered structure; ii. a rotatable fan disposed within said chambered structure; iii. a mounting point configured to removably secure one of said one or more VOC retainer within said chambered structure in a position between said at least one vent and said fan; iv. a rotational drive part connected to and / or configured to rotate, independently or concurrently, said fan and, when placed in said mounting point, said VOC retainer; v. a power source configured to provide power to said rotational drive part; and, optionally, vi. control electronics configured to control the timing and / or speed of rotation of said rotational drive part, said VOC retainer and said fan, wherein each of said one or more VOC retainer comprises, or is configured to contain, an insect repellent or insecticidal composition comprising one or more active VOC compounds, and wherein the size of the VOC retainer and the rotational speed of the rotational drive part are selected such that, upon controlled rotation of said rotational drive part, said VOC retainer is subject to relative centrifugal force (RCF) of from about 25 g to about 75 g.

18. The kit of parts according to claim 17, comprising a plurality of said VOC retainers, wherein each of said plurality of VOC retainers optionally comprises or is configured to contain a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound and / or multiple combinations thereof.

19. The kit of parts according to claim 18, wherein each of said plurality of VOC containers is segmented into a plurality of physically discrete sections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

20. A method of controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing the device according to any one of claims 1 to 16; b. rotating said rotational drive part, said VOC retainer and said fan, wherein said VOC retainer is rotated at a speed such that it is subject to a relative centrifugal force (RCF) of from about 25 g to about 75 g; and, optionally, c. refilling said VOC retainer with said insect repellent or insecticidal composition, or alternatively replacing said VOC retainer with a second VOC retainer in said chambered structure, before repeating step b.21 .A method for controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing the kit of parts according to any of claims 17 to 19, and inserting a first VOC retainer into the mounting point of said housing; b. rotating said rotational drive part, said first VOC retainer and said fan, wherein said first VOC retainer is rotated at a speed such that it issubject to a relative centrifugal force (RCF) of from about 25 g to about 75 g and, optionally, c. refilling said first VOC retainer with said insect repellent or insecticidal composition, or alternatively replacing said first VOC retainer with a second VOC retainer on said mounting point, before repeating step b.

22. The method according to claim 20 or claim 21 , wherein: a. said VOC retainer is refilled in step c) with a second insect repellent or insecticidal composition comprising a different active VOC compound and / or a different synergist or effector compound; or b. said second VOC retainer container comprises an insect repellent or insecticidal composition comprising a different active VOC compound and / or a different synergist or effector compound to the insect repellent or insecticidal composition of said (first) VOC retainer.

23. The method according to any of claims 20 to 22, wherein rotation step b) is performed according to a pre-programmed duty cycle.

24. An insect control device, said device comprising: a. a volatile organic chemical (VOC) retainer; b. an active VOC disperser; c. a power source configured to provide power to said VOC disperser; and, optionally, d. control electronics configured to control the actuation of said VOC dispenser and / or control the discharge of VOCs from said device, wherein said VOC retainer comprises, or is configured to contain, a plurality of insect repellent or insecticidal compositions, wherein each of said plurality of insect repellent or insecticidal compositions comprises a different active VOC compound and / or a different synergist or effector compound, and wherein said VOC retainer is optionally segmented into a plurality of physically discretesections, and wherein each section comprises, or is configured to contain, a different insect repellent or insecticidal composition.

25. A method for controlling insects by discharging one or more insect repellent or insecticidal VOCs into the air, said method comprising: a. providing an insect control device, said device comprising: i. a removable, replaceable and / or refillable first volatile organic chemical (VOC) retainer, wherein said VOC retainer comprises, or is configured to contain, a first insect repellent or insecticidal composition comprising one or more active VOC compounds; ii. an active VOC disperser; iii. a power source configured to provide power to said VOC disperser; and, optionally, iv. control electronics configured to control the actuation of said VOC dispenser and / or control the discharge of VOCs from said device, b. actuating said VOC disperser to discharge said one or more active VOC compounds from said first insect repellent or insecticidal composition into the environment; c. refilling said first VOC retainer with a second insect repellent or insecticidal composition, or alternatively replacing said first VOC retainer with a second VOC retainer comprising said second insect repellent or insecticidal composition; and d. actuating said VOC disperser to discharge said one or more active VOC compounds from said second insect repellent or insecticidal composition into the environment, wherein said first and said second insect repellent or insecticidal compositions comprise a different active VOC compound and / or a different synergist or effector compound.

26. The device of claim 24 or the method of claim 25, wherein said active VOC disperser comprises or consists of a heating element and / or a fan.

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