WO2008099297A1

WO2008099297A1 - Insect repelling device

Info

Publication number: WO2008099297A1
Application number: PCT/IB2008/050410
Authority: WO
Inventors: Peter Yiga Lubega
Original assignee: Peter Yiga Lubega
Priority date: 2007-02-15
Filing date: 2008-02-05
Publication date: 2008-08-21

Abstract

This invention relates, to a mosquito repelling device including a receptacle (15) for receiving biochemical material which is capable of undergoing a biochemical reaction in the form of fermentation to release C02 and pungent odours resulting from the fermentation; and a housing (25) dimensioned and configured to enhance, the release and propagation of the C02 and pungent odours the air, in order to repel the insects.

Description

INSECT REPELLING DEVICE

Field of the Invention

THIS invention relates to an insect repelling device. More particularly, but not exclusively, this invention relates to a mosquito and night flying insect repelling device.

Background to the Invention

Vector-borne diseases are among the most important public health problems and obstacles to socioeconomic development of developing countries, particularly in the tropics, with malaria alone causing an estimated 1 .5 - 2.7 million deaths and 300 - 500 million cases per year (World Health Organisation, 1997. World Malaria Situation in 1994, Part 1 , WkIy Epidemiol Rec 72: 269-274).

At the end of 2004, 107 countries and territories had areas at risk of malaria transmission. Some 3.2 billion people lived in areas at risk of malaria transmission.

An estimated 350-500 million clinical malaria episodes occur annually; most of these are caused by infection with P. falciparum and P. vivax. Falciparum malaria causes more than 1 million deaths each year. It also contributes indirectly to many additional deaths, mainly in young children, through synergy with other infections and illnesses.

Patterns of malaria transmission and disease vary markedly between regions and even within individual countries. This diversity results from variations between malaria parasites and mosquito vectors, ecological conditions that affect malaria transmission and socioeconomic factors, such as poverty and access to effective health care and prevention services.

About 60% of the cases of malaria worldwide, about 75% of global falciparum malaria cases and more than 80% of malaria deaths occur in Africa south of the Sahara. P. falciparum causes the vast majority of infections in this region and about 18% of deaths in children under 5 years of age. Malaria is also a major cause of anaemia in children and pregnant women, low birth weight, premature birth and infant mortality. In endemic African countries, malaria accounts for 25-35% of all outpatient visits, 20-45% of hospital admissions and 15-35% of hospital deaths, imposing a great burden on already fragile health-care systems.

Evidence continues to accumulate to support the view that adults infected with HIV, in addition to children under 5 years of age and pregnant women, should be targeted for malaria prevention and treatment. Malaria contributes synergistically with HIV/AIDS to morbidity and mortality in areas where both infections are highly prevalent, such as in Africa south of the Sahara. In addition to providing immediate health benefits, prevention and treatment of malaria may lessen transient increases in HIV viral load during malaria episodes and thus help limit the progression and transmission of

HIV.(WORLD MALARIA REPORT 2005 by Roll Back Malaria, WHO &

UNICEF. EXECUTIVE SUMMARY. Global burden of malaria: xvii)

To date, no method of malaria control has proven effective enough to control the high transmission intensities found in sub-Saharan Africa (Lengeler C, Smith TA, Armstrong-Schellenberg J, 1997).

With the ever increasing resistance to insecticides and malarial drugs, finding new tools and methods to fight malaria is gaining renewed momentum.

Bed nets, with or without some form on anti- repellant composition, are very popular but are only effective to the extent that a person is under the net.

Mosquito repellant devices exist which produce carbon dioxide. These are of course misnamed since their purpose is to actually attract mosquitoes and trap them once they have entered into the device. In doing so, a mosquito may not necessarily be immediately attracted thereto and the efficacy of such devices is questionable. Object of the Invention

It is an object of the invention to provide an alternative insect repelling device.

It is a further object of the invention to provide an alternative insect, particularly but not exclusively mosquitoes and night flying insects, repelling device which at least partially minimizes the disadvantages set out above.

Summary of the Invention

According to the present invention there is provided an insect repelling device including a receptacle for receiving biochemical material which is capable of undergoing a biochemical reaction in the form of fermentation to release carbon dioxide and pungent odours resulting from the fermentation; and a housing dimensioned and configured to enhance the release and propagation of the carbon dioxide and pungent odours into the air, in order to repel insects.

The device is primarily aimed at repelling insects such as mosquitoes but may also be effective in repelling night flying insects and spiders.

Release and Propagation of CO? and odours

The housing is dimensioned and configured such that the accumulation of CO₂ and odours within the device is achieved. In use, the accumulation of CO₂ within the device will result in a high concentration of CO₂ therein.

The housing is further dimensioned and configured to allow for the controlled release of CO₂ and odours into the air. It is envisaged that the CO₂, and odours will first build up in the device and then will be released into the air. The Biochemical Material

In its simplest form the biochemical material may be a combination of sugar and yeast.

It will be appreciated by those skilled in the art that any suitable forms of sugar may be used.

The preferred sugar sources include mostly fermentable sugars such as sugar, cane sugar, sweet sorghum, saccharose, beta-d- fructofuranosyl-allpha-d-glucopyranoside, beta-d-fructofuranoside, beet sugar, confectioner's sugar, granulated sugar, NCI-C56597, icing sugar, rock candy, saccharum.

Derivatives of sugar such as molasses, cane top, filter press mud and the like can also be used as substitutes.

Liquid sugars such as sugar cane juice, honey (diluted with water) can also act as energy sources in the fermentation process. It must be noted that fermentation is the only microbiological alteration to which honey is susceptible.

Non-fermentable sugars can also be converted into fermentable sugars to enable them to produce similar biochemical reactions.

Any suitable yeast may be used for the fermentation process. In a preferred form of the invention, active dry yeast is used. More preferably yeast of the genus Saccharomyces is used in the current invention. Saccharomyces cerevisiae and Saccharomyces bayanus are the preferred species because they are industrial yeast. It is acknowledged that other Saccharomyces species can be used. Active dry yeasts are used so as to create a biochemical reaction in the form of fermentation. Saccharomyces converts sugars such as glucose, fructose and sucrose into ethanol via the process of fermentation.

The following sugars may be used with Saccharomyces: Monosaccharides: glucose, fructose, galactose, mannose Disaccharides: sucrose, maltose, melibiose, xylulose Trisaccharides: raffinose, maltotriose

Oxidative Substrates: pyruvate, acetate, lactate, glycerol, ethanol

In an embodiment of the invention the biochemical material comprises a dry formulation wherein between 35Og and 60Og, preferably 45Og of sugar is mixed with 1 Og to 2Og, preferably 15g of yeast. The preferred ratio of yeast to sugar is 0.03: 1 ± 10%.

The dry formulation has a pH of from 3.5 to 5.5, preferably the pH is 3.45.

In a preferred form of the invention between 45Og -50Og of dry formulation is immersed in 500ml of water in the device of the invention.

In an embodiment of the invention, the amount of sugar added to the amount of water is in a 1 : 1 ratio ± 10%.

It is envisaged by the inventor that an excess amount of carbon dioxide is produced by the biochemical reaction so as to contribute to the repulsion of insects such as mosquitoes.

Additional ingredients may be added to the biochemical material such as essential oils well known in the art to repel insects.

The Housing

The housing is preferably dimensioned such that it has a length of from 400mm to 1500mm, preferably 800mm to 1200mm, and more preferably is 1000mm in length. The housing may be tubular or conical or any other shape suitable for enhancing the release of the CO₂, and the pungent odours into the air. It will be appreciated that for the release of the CO₂ and the like the housing has an aperture at a free end thereof to allow for the release thereof into the air. The housing may also include apertures therein in order to allow for the controlled release of the CO₂ and the pungent odours. The apertures may be closable.

In a preferred form of the invention, the housing comprises a base portion and a plurality of inter-connectable sections. The inter- connectable sections may all be conical in shape.

It will be appreciated that the amount of CO₂ generated from the fermentation process may cause the surface of the biochemical material to fizzle and mix with a buzzing hiss that may be disquieting to insects. The housing may also thus serve the purpose of enhancing these acoustic effects.

It is envisaged that the dimensions of the housing may be in proportion to the amount of biochemical material used.

It is further envisaged that the combined synergistic effect of the pungent odours, carbon dioxide and the acoustic waves enhanced and emitted from the housing repel insects such as mosquitoes and the like.

Brief Description of the Drawings

Figure 1 is a partial section view of the front of the mosquito repelling device according to the invention.

Figure 2 is a side view of the housing of the device according to the invention wherein the housing comprises inter-connectable segments.

Figure 3 is a perspective view of the apparatus used for purposes of an experiment wherein the device according to the invention was tested. Detailed Description of the Invention

The mosquito repelling device according to the invention is designated generally by the number 10.

Referring to Figure 1 , the mosquito repelling device 10 includes a receptacle 15 for receiving biochemical material such as 500 g of sugar and 15 g of yeast in order to result in a biochemical reaction in the form of fermentation.

The receptacle 15 has threaded ends 20 so that it may be secured to the housing 25, which contains complementary threads for being secured to the receptacle 15. It will be appreciated that this is merely the preferred embodiment and the receptacle 15 could be secured to the housing 25 in any other suitable way, or it could form an integral part of the housing 25.

The housing 25 is dimensioned and configured to enhance the acoustic waves resulting from the biochemical reaction and is provided in the form of a cone having a length, together with the receptacle 15, of at least 1000mm.

The housing is further provided with apertures 30, as shown in figure 1 , that are closable in part or in total, in order to release carbon dioxide formed by the fermentation process. These apertures may be provided in any particular manner and in any particular pattern however, without derogating from their function.

Figure 2 is an alternate embodiment of the invention wherein the housing 25 comprises three segments 25.1 , 25.2 and 25.3 which are each inter-connectable by virtue of being complimentarily threaded and each of the segments being conical in shape.

Field Experiments

The nature of the invention is such that it repels mosquitoes and other night flying insects throughout the hut, enclosure or house (3 roomed) in which it is operational. While small households could be completely protected from mosquitoes with a single device, bigger households or enclosures should use more than one device to ensure complete protection.

To demonstrate the repellent effect of the invention, various field experiments were conducted in different geographical locations in Africa ranging from East Africa to Southern Africa.

The first set of field experiments were conducted in Kampala, Uganda over a 4 month period (i.e. April - July 2005). 3-bedroomed houses in three different locations were used for the experiments.

The second set of field experiments were conducted inside a house in Mafikeng, Northwest Province, South Africa (i.e. December 2005 -

January 2006). While this area is not a malaria risk area, there were nonetheless a lot of mosquitoes during the November 2005 - January

2006 period. Even though these mosquitoes are not malaria vectors, it was observed that the device described above had a repellency effect on them.

The third set of field experiments were conducted inside a hut in Punda Maria with observations from a team of entomologists from the Malaria Institute in Tzaneen, South Africa. Punda Maria lies within the Kruger National Park. Vector and nuisance mosquitoes are abundant in this region of South Africa. The town falls within the malaria risk area in South Africa. It has both Zimbabwe and Mozambique bordering it. Malaria cases are reported frequently in this area.

In all of the above cases, the effect of the device was such that on the first night, no appreciable effect was observed. This is because the biochemical reaction described in the invention takes a few hours to get underway. (In all field experiments, the biochemical material to produce the biochemical reaction was placed in the said invention at about 17h00 in the evening). However on the second night and for more than 20 nights there after very few if any mosquitoes were observed. The inhabitants of the houses and/or hut did not experience any bites whatsoever. The few mosquitoes seen to occasionally venture into the house in which the device was operational seemed to lose their feeding frenzy. They seemed to become incapacitated and did not fly around in their usual manner. It is also important to note that no other forms of mosquito repellents were used, and no netting was used for the windows and the like of the houses to prevent ingress by the mosquitoes.

Laboratory Experiments

To demonstrate the repellant effects of the device according to the invention, experiments were conducted in insectaries at the NHLS National Health Laboratory Service) in Sandringham, Gauteng, South Africa.

A perspex chamber (75 x 20 x 10 cm)50 connected to a netted chamber 40 (30 x 30 x 25 cm) was used in the experiment and is shown in Figure 3. Sucrose solution placed in both chambers was used to feed the mosquitoes. A laboratory colony of 60 female Anopheles Gambia maintained at the NHLS was used. The mosquitoes were free to move between the two chambers as shown in figure 3 below through passage 45. The biochemical material according to the invention was introduced into the one chamber. It is to be noted that the preferred dimensions of the device were not utilized due to the size of the Perspex chamber.

All 60 mosquitoes were released into the perspex chamber and readings were taken every 24hrs over a 4 day period (i.e. 96 hours), however the results of the last 3 days of the 4 day period are reported below as it is believed that it would take up to 24 hours for the device to become fully effective. Since the device according to the invention does not actually kill mosquitoes, all deaths were treated as natural deaths. Readings of the number of mosquitoes in each of the chambers were taken over the 4 day period. A control experiment was conducted 3 days after the end of the main experiment. Two days was allowed to clear the room of any effects from the device according to the invention. The same setup as described above was used without the device according to the invention. Another colony of 60 female Anopheles Gambia was used in the control experiment. Readings of the number of mosquitoes in each of the chambers were also taken over a 4 day period but for the sake of consistency, only the last 3 days are reported below.

A Migration Quotient (MQ) was used in the statistical analysis of the experiment. It is derived by dividing the number of mosquitoes in chamber A (i.e. the perspex chamber) by the number of mosquitoes in chamber B (i.e. the netted chamber). Under normal circumstances, it would be expected to have an equal number of mosquitoes in both chambers.

Therefore, with 60 mosquitoes, expected MQ = 30/30 = 1 . An MQ < 1 implies that there are less mosquitoes in chamber A while MQ > 1 implies that there are more mosquitoes in chamber A. It was noted that the percentage of mosquitoes in the perspex chamber A (i.e. the chamber with device according to the invention), was less than 10% (i.e. MQ far below 1 ) throughout the duration of the experiment (i.e. throughout the 96 hours).

In the control experiment, the average percentage of mosquitoes in the Perspex chamber A was about 44%. (i.e. MQ close to 1 ). While there was an observable repellency effect of the device according to the invention, further statistical analysis of the results revealed that the device according to the invention's repellent effect was statistically significant. Table 1 : Lab Test Results

It is envisaged that the device according to the invention will provide the following advantages:

Repulsion of mosquitoes and other night flying insects from a household (or enclosure) cheaply and cost effectively.

Does not require application to the skin and is not burnt and thus does not produce any fumes and thus does not pose any danger to its users.

Does not use chemicals or insecticides, is environmentally friendly, and effective at ensuring that mosquitoes and various other species of night flying insects are repelled from the household or enclosure in which the device is operational.

The above is only one embodiment of the invention and it will be appreciated that many variations in detail are possible without thereby departing from the scope and spirit of the invention. So, for example, the housing may be provided in any suitable shape for collecting and dissipating (in a controlled manner) the CO₂ and pungent odours and enhancing the acoustic effects resulting from the fermentation process. Further, fragrances may be added to the device and the device itself may be modified to add attachments thereto such that it may perform an additional function of being a pot holder Still further, and to allow the device to be sold at a low cost, the receptacle for receiving the biochemical material may be a 21 PET bottle.

Claims

Claims:

1 . An insect repelling device including a receptacle for receiving biochemical material which is capable of undergoing a biochemical reaction in the form of fermentation to release CO₂ and pungent odours resulting from the fermentation; and a housing dimensioned and configured to enhance the release and propagation of the CO₂ and pungent odours into the air, in order to repel the insects.

2. The device of claim 1 , wherein the housing is dimensioned to be conical in shape.

3. The device of claim 1 , wherein the housing includes an aperture at a free end thereof to allow for the release of the CO₂ and pungent odours into the air.

4. The device of claim 1 , wherein the housing is configured to include a plurality of apertures therein so as to allow for the controlled release of the CO₂ and pungent odours.

5. The device of claim 4, wherein the apertures are closeable.

6. The device of claim 1 , wherein the housing has a length of from 400mm to 1500mm.

7. The device of claim 1 , wherein the biochemical reaction produces acoustic effects, the propagation of which is enhanced by the housing.

8. The device of claim 1 , wherein the biochemical material comprises a combination of sugar and yeast.

9. The device of claim 1 , wherein the biochemical material has a pH of from 3.5 to 5.5.

10. The device of claim 8, wherein the ratio of yeast to sugar is 0.03: 1 .0 ± 10%.

1 1 . The device of claim 1 , wherein the dry formulation is combined with water.

12. The device of claim 1 , wherein the biochemical material includes essential oils for the repulsion of insects.

13. The device of claim 1 , wherein the insects are selected from the group consisting of mosquitoes, night flying insects and spiders.