JP7655014B2 - Infection risk measurement system, infection risk judgment system, and infection risk measurement method - Google Patents

Description

This disclosure relates to an infection risk measurement system, an infection risk determination system, and an infection risk measurement method.

Conventionally, the ATP (adenosine triphosphate) swab test shown in Patent Document 1 has been known as a test for checking the cleanliness of the surface of a measurement target area. The ATP swab test can measure the amount of ATP contained in the test sample by reacting a test sample obtained by swabbing the surface of the measurement target area with a luminescent reagent containing luciferase and measuring the amount of luminescence produced by the reaction.

JP 2003-35673 A

ATP is present in microorganisms such as bacteria, and the reaction solution between the test sample and the luminescent reagent emits light in proportion to the amount of ATP. Therefore, ATP swab tests can easily evaluate the degree of microbial contamination of the measurement area. However, viruses do not synthesize ATP themselves, and do not possess ATP. Therefore, it is not easy to determine the risk of viral infection using ATP swab tests alone.

Therefore, the present disclosure aims to provide an infection risk measurement system, an infection risk determination system, and an infection risk measurement method that are capable of determining the risk of viral infection.

The infection risk measurement system according to the present disclosure includes a first measurement unit that measures the amount of adenosine triphosphate or a first parameter that is a parameter corresponding to the amount of adenosine triphosphate. The infection risk measurement system includes a second measurement unit that measures the amount of a component contained in human body fluid or a second parameter that is a parameter corresponding to the amount of the component. The infection risk measurement system includes a determination unit that refers to reference data in which an infection risk level is pre-assigned for each combination of the value of the first parameter and the value of the second parameter, and determines the infection risk level of the surface of the measurement target location based on the combination of the value of the first parameter measured by the first measurement unit and the value of the second parameter measured by the second measurement unit for a test sample collected from the surface of the measurement target location. The infection risk measurement system includes an output unit that outputs the determination result determined by the determination unit.

The parameter corresponding to the amount of adenosine triphosphate may be the amount of luminescence produced by the action of luciferase.

The parameter corresponding to the amount of the above component may be at least one of the electrical conductivity and the ion concentration.

The above component may be a protein contained in human saliva, and the parameter corresponding to the amount of the above component may be protein activity.

The value of the second parameter of the test sample may be corrected according to at least one of the ambient temperature and ambient humidity of the measurement location, and the determination unit may determine the infection risk level based on a combination of the value of the first parameter measured by the first measurement unit for the test sample and the corrected value of the second parameter.

The reference data may be assigned in advance an infection risk level for each combination of the surface material of the measurement location, the value of the first parameter, and the value of the second parameter, and the determination unit may refer to the reference data to determine the infection risk level according to the material.

The infection risk determination system according to the present disclosure includes an input unit for inputting the amount of adenosine triphosphate in a test sample collected from the surface of a measurement target location or the value of a first parameter which is a parameter corresponding to the amount of adenosine triphosphate, and the amount of a component contained in a human body fluid in the test sample or the value of a second parameter which is a parameter corresponding to the amount of the component. The infection risk determination system includes a determination unit which refers to reference data in which an infection risk level is pre-assigned for each combination of the value of the first parameter and the value of the second parameter, and determines the infection risk level of the surface of the measurement target location based on the combination of the value of the first parameter input from the input unit and the value of the second parameter input from the input unit. The infection risk determination system includes an output unit which outputs the determination result determined by the determination unit.

The infection risk measurement method according to the present disclosure includes a step of measuring a first parameter, which is an amount of adenosine triphosphate or a parameter corresponding to the amount of adenosine triphosphate. The method includes a step of measuring a second parameter, which is an amount of a component contained in a human body fluid or a parameter corresponding to the amount of the component. The method includes a step of referring to reference data in which an infection risk level is pre-assigned for each combination of the value of the first parameter and the value of the second parameter, and determining the infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured for a test sample collected from the surface of the measurement target location and the value of the second parameter measured for the test sample. The method includes a step of outputting the determined determination result.

The present disclosure provides an infection risk measurement system, an infection risk determination system, and an infection risk measurement method that are capable of determining the risk of virus infection.

1 is a schematic diagram showing an infection risk measurement system according to one embodiment. FIG. 13 is a diagram illustrating a decision map according to an embodiment. 11 is a flowchart showing a processing procedure of the infection risk measurement system. 1 is a graph in which the measurement results of Reference Examples 1 and 2 are plotted. 1 is a graph in which the measurement results of Reference Examples 3 and 4 are plotted. 1 is a graph in which the measurement results of Reference Example 5 are plotted. 1 is a graph in which the measurement results of Reference Example 6 are plotted. 1 is a graph in which the measurement results of Reference Example 7 are plotted. 1 is a graph in which the measurement results of Reference Example 8 are plotted.

Below, several exemplary embodiments will be described with reference to the drawings. Note that the dimensional ratios in the drawings have been exaggerated for the convenience of explanation and may differ from the actual ratios.

As shown in FIG. 1, the infection risk measurement system 1 according to this embodiment includes a first measurement unit 10, a second measurement unit 20, a determination unit 30, a thermometer 31, a hygrometer 32, a numerical input unit 40, and an output unit 50. In the infection risk measurement system 1, a test sample collected from the surface of a measurement target location is measured by the first measurement unit 10 and the second measurement unit 20, and the infection risk level is determined by the determination unit 30.

The surface shape and material of the measurement target area are not particularly limited. Specifically, the surface shape of the measurement target area may be flat or may have irregularities. The material of the measurement target area may be plastic, rubber, metal, cloth, wood, paper, concrete, ceramics, etc. The measurement target area may be the surface of a tangible object present in the room.

The first measuring unit 10 measures the amount of ATP or a first parameter which is a parameter corresponding to the amount of ATP. ATP is used as an energy source for cells in various reactions, since energy is released when ATP is hydrolyzed into ADP (adenosine diphosphate) and inorganic phosphate. Viruses do not normally possess ATP, but human body fluids such as saliva and nasal mucus contain microorganisms such as bacteria, and ATP exists in the microorganisms. Therefore, the first parameter is an index for evaluating the amount of microorganisms attached to the surface of the measurement target area. The amount of ATP measured by the first measuring unit 10 may be an amount expressed in grams, an amount expressed in volume, or an amount expressed in moles.

The parameter corresponding to the amount of ATP may be the amount of luminescence produced by the action of luciferase. Since the amount of luminescence produced by the action of luciferase is proportional to the amount of ATP, the amount of ATP can be easily measured on the spot by measuring the amount of luminescence in the test sample. An example of such a measurement method using luminescence is the ATP swab test method. Specifically, the first measurement unit 10 may include a luminometer capable of measuring the amount of luminescence. The luminometer may include a sample holding unit 11, a detection unit 12, and a calculation unit 13.

The sample holder 11 is provided so as to be capable of holding a sample container. The sample container contains a reaction liquid obtained by reacting a test sample with a luminescent reagent. The test sample can be collected from the surface of the measurement target area using a wiping member such as a cloth or a cotton swab. The luminescent reagent may contain luciferase, luciferin, and magnesium ions. By contacting the test sample attached to the wiping member with the luminescent reagent, the ATP contained in the test sample reacts with the luciferin contained in the luminescent reagent due to the catalytic action of luciferase, and the reaction product generated by the reaction emits light.

The detection unit 12 may include a photodiode or a photomultiplier tube. The detection unit 12 detects light emitted from the reaction solution by the catalytic action of luciferase, and generates an electrical signal corresponding to the amount of light detected. The electrical signal generated by the detection unit 12 is transmitted to the calculation unit 13.

The calculation unit 13 includes a processor and calculates the amount of light emitted (RLU: Relative Light Unit) from the electrical signal generated by the detection unit 12. Since the amount of light emitted is proportional to the amount of ATP, the calculation unit 13 may calculate the amount of ATP from the electrical signal generated by the detection unit 12.

Although an example has been described in which the parameter corresponding to the amount of ATP is the amount of luminescence, the parameter corresponding to the amount of ATP may be at least one of the amount of luminescence and the ATP concentration. The ATP concentration can be obtained by measuring the amount of ATP in an aqueous solution in which a test sample is dissolved.

The first measurement unit 10 measures the first parameter as described above. However, even if the value of the first parameter measured by the first measurement unit 10 is large and the amount of ATP is large, there is a possibility that the ATP is derived from fungi growing naturally on the surface of the measurement target area. Therefore, there is a risk that the risk of infection by a virus cannot be appropriately evaluated by measuring only the first parameter. Therefore, the infection risk measurement system 1 according to this embodiment is equipped with a second measurement unit 20.

The second measuring unit 20 measures the amount of a component contained in the human body fluid or a second parameter which is a parameter corresponding to the amount of the component. By measuring the second parameter by the second measuring unit 20, an index can be obtained which indicates the amount of body fluid scattered by coughing, sneezing, talking, etc., which has adhered to the measurement target location. The amount of a component contained in the human body fluid may be an amount expressed in grams, an amount expressed in volume, or an amount expressed in moles.

The parameter corresponding to the amount of the component may be at least one of the conductivity and the ion concentration. That is, the second measurement unit 20 may measure the conductivity and the ion concentration, or may measure either the conductivity or the ion concentration. This allows the second measurement unit 20 to measure the second parameter quickly and easily. The second measurement unit 20 may measure the conductivity or the ion concentration of an aqueous solution in which the test sample is dissolved in water.

Conductivity can be measured using a conductivity meter or a salinity meter. For example, saliva contains inorganic components such as sodium ions, potassium ions, calcium ions, and chloride ions. The more of these inorganic components present in the water, the higher the conductivity value of the aqueous solution tends to be. Therefore, by measuring the conductivity of a test sample, the amount of components contained in the body fluid can be indirectly measured. Conductivity can be measured using any method, such as the AC two-electrode method, the AC four-electrode method, or the electromagnetic induction method.

The ion concentration can be measured by an ion sensor or a salinity meter. The ion sensor may include at least one sensor selected from the group consisting of a sodium ion sensor, a potassium ion sensor, a calcium ion sensor, and a chloride ion sensor. The sodium ion sensor measures the sodium ion concentration, the potassium ion sensor measures the potassium ion concentration, the calcium ion sensor measures the calcium ion concentration, and the chloride ion sensor measures the chloride ion concentration. The ion sensor includes an ion selective electrode that selectively responds to ions contained in human body fluids. The ion selective electrode includes a sensitive membrane that selectively interacts with a specific ion as described above. The sensitive membrane may be a solid membrane or a liquid membrane. The sensitive membrane may include a support and a solution held by the support and in which an ion exchanger or a neutral carrier is dissolved in a solvent. Examples of neutral carriers include valinomycin and crown ether.

The salinity meter can measure the salinity of a test sample. As described above, for example, saliva contains sodium ions and chloride ions, so by measuring the salinity with a salinity meter, the amount of components contained in the body fluid can be indirectly measured. The salinity meter may measure the salinity using the electrical conductivity method or the ion electrode method.

The components contained in the body fluid may be proteins contained in human saliva, and the parameter corresponding to the amount of the components may be protein activity. This makes it possible to more reliably determine whether the test sample contains a component derived from saliva. The second measurement unit 20 may measure the activity of proteins in an aqueous solution obtained by dissolving the test sample in water. Examples of proteins contained in saliva include enzymes such as amylase and maltase, and glycoproteins such as lactoferrin.

The activity of the protein may be amylase activity. That is, the second measurement unit 20 may measure the amylase activity. Specifically, the second measurement unit 20 may measure the amylase activity by utilizing the hydrolysis action of amylase contained in the test sample. The amylase activity can be measured by contacting an aqueous solution in which the test sample is dissolved in water with a substrate and measuring the color development of molecules liberated by decomposition of the substrate. An example of the substrate is a molecule having CNP (2-chloro-4-nitrophenol), such as Gal-G2-CNP (2-chloro-4-nitrophenyl-4-galactopyranosylmaltoside). Amylase activity can be easily confirmed by measuring the color development of the liberated CNP after decomposition of such a substrate. The color development can be measured using a color difference meter or an absorptiometer.

The determination unit 30 refers to the reference data and determines the infection risk level of the measurement target location based on a combination of the value of the first parameter in the test sample measured by the first measurement unit 10 and the value of the second parameter in the test sample measured by the second measurement unit 20. This makes it possible to determine the infection risk level for a virus that could not be determined by an ATP test alone. The determination unit 30 may be electrically connected to the first measurement unit 10 and the second measurement unit 20 by wire or wirelessly.

The reference data is assigned an infection risk level in advance for each combination of the value of the first parameter and the value of the second parameter. The reference data may be, for example, a judgment map. The judgment map can be created, for example, as follows. First, a plurality of reference samples for creating the judgment map are prepared. The plurality of reference samples are obtained from a plurality of different measurement target locations. It is preferable that the measurement target locations for creating the reference samples have different degrees of adhesion of human body fluids and ATP. Examples of such measurement target locations include, for example, plastic plates, gloves before and after use, palms, staircase handrails, desks, and dining tables, as shown in the reference examples described below. The measurement target locations may be pseudo samples that assume the case where an infected person splashes saliva droplets. For example, a saliva imitation liquid may be prepared and the imitation liquid may be sprayed onto plastic.

Next, the first parameter of each reference sample is measured by the first measurement unit 10, and the second parameter is measured by the second measurement unit 20. The measured first parameter value and second parameter value are then plotted on a graph for each reference sample. The graph may be a linear graph, a semi-logarithmic graph, or a double logarithmic graph. An infection risk level is then set for the graph on which the measurement results of multiple reference samples are plotted, depending on the properties of each reference sample. Specifically, as shown in FIG. 2, virus infection risk levels may be divided into areas A, B, C, D, and E, and an infection risk level may be assigned to each combination of the first parameter value and the second parameter value.

Area A is the area in which the value of the amount of luminescence as the first parameter and the value of the electrical conductivity as the second parameter are the largest. Therefore, area A is likely to be contaminated by saliva, etc., and is therefore the area considered to have the highest risk of infection.

Area B has a smaller luminescence value than area A, but a high conductivity value, just like area A. Therefore, area B is likely to be frequently touched by people, and is thought to be an area where there is human contamination other than saliva, or where time has passed since contamination by saliva or the like, causing the virus activity to decrease. Therefore, area B is thought to have a lower risk of infection than area A.

Area C is the area with the smallest luminescence value and conductivity value. Therefore, Area C is an area that has been cleaned, and even if it has been contaminated by saliva droplets in the past, it is an area where the amount of virus present is thought to have been reduced by cleaning. Therefore, Area C is the area that is thought to have the lowest risk of infection.

Area D has a high conductivity value like areas A and B, but a lower luminescence value than areas A and B. Area D is an area that may have been contaminated by saliva droplets or human contact, but time has passed since contamination and the activity of the virus is thought to have decreased. Therefore, area D is an area where the risk of infection is thought to be lower than area B.

Area E has a high luminescence value like Area A, but a lower conductivity value than Area A. Area E is an area where the possibility of the presence of microorganisms is high, but the possibility of human contamination is considered low. Therefore, Area E is an area where the risk of infection is considered to be lower than Area A.

In this embodiment, the determination map is divided into areas A to E, but the total number of areas and the size of each area can be set as appropriate. For example, areas A and B may be divided into area Z, which has a higher infection risk level than areas C, D, and E.

In addition, the reference data may be assigned an infection risk level in advance for each combination of the material of the measurement location, the value of the first parameter, and the value of the second parameter, and the determination unit 30 may refer to the reference data and determine the infection risk level according to the material of the measurement location. Since the survival time of a virus varies depending on the material to which it is attached, the infection risk level can be measured more accurately by determining the infection risk level according to the material of the measurement location. As described above, the reference data may be prepared by measuring the first and second parameters of multiple reference samples for each material, plotting the obtained values on a graph for each reference sample, and assigning an infection risk level.

The judgment unit 30 judges the infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured by the first measurement unit 10 and the value of the second parameter measured by the second measurement unit 20 for the test sample by referring to the reference data. The judgment unit 30 may include a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU can read the program and reference data stored in the ROM and judge the infection risk level of the measurement target location according to the program. The above-mentioned judgment map may be stored in the ROM in the form of a data table. The program and reference data may be stored in an external storage device (not shown). The RAM temporarily stores information acquired from the first measurement unit 10, the second measurement unit 20, the thermometer 31, the hygrometer 32, etc., and the CPU can read the information stored in the RAM and use it for processing such as calculations.

It is preferable that each reference sample and test sample is collected so that the surface area of the portion collected from the measurement target location is the same, or that the values of the first parameter and the second parameter of the test sample are corrected so that the surface areas of the portions collected are the same.

The value of the second parameter of the test sample may be corrected according to at least one of the ambient temperature and ambient humidity of the measurement target location. The judgment unit 30 may then judge the infection risk level based on a combination of the value of the first parameter measured by the first measurement unit 10 for the test sample and the corrected value of the second parameter. The ambient temperature and ambient humidity affect the inactivation state of the virus. For example, when the ambient temperature is high, the virus is more likely to be inactivated. Therefore, the judgment unit 30 may correct the value of the second parameter measured by the second measurement unit 20 using a coefficient or the like determined in advance through experiments or the like, and judge the risk of infection based on the value of the first parameter measured by the first measurement unit 10 and the corrected value of the second parameter. The judgment unit 30 may correct the value of the second parameter based on the ambient temperature measured by the thermometer 31 and the ambient humidity measured by the hygrometer 32. The ambient temperature and ambient humidity may also be input by the user via the numerical input unit 40, and the judgment unit 30 may correct the value of the second parameter based on the input ambient temperature and ambient humidity. The numerical value input unit 40 may include a keyboard or touch panel that can input numerical values.

The output unit 50 outputs the judgment result judged by the judgment unit 30. The output unit 50 may be a display or a printer. The output unit 50 may output the above-mentioned areas A to E as the judgment result as is, or may output the judgment result in which areas A to E are interpreted as risk level 1 to risk level 5, respectively. The output unit 50 may also output the judgment result in which area A is interpreted as high level, area B as middle level, and areas C to E as low level.

Next, the processing procedure of the infection risk measurement system 1 according to this embodiment will be explained using the flowchart in FIG. 3.

When the measurement by the infection risk measurement system 1 is started, in step S101, the first measurement unit 10 measures the first parameter of the test sample. In step S102, the second measurement unit 20 measures the second parameter of the test sample. In step S103, the judgment unit 30 reads out judgment data from the ROM. In step S104, the judgment unit 30 refers to the judgment data and judges the infection risk level of the measurement target location based on the combination of the value of the first parameter and the value of the second parameter of the test sample. In step S105, the output unit 50 outputs the judgment result judged by the judgment unit 30, and the measurement by the infection risk measurement system 1 ends. In the flowchart, the first measurement unit 10 measures the first parameter, and then the second measurement unit 20 measures the second parameter. However, the first measurement unit 10 may measure the first parameter after the second measurement unit 20 measures the second parameter. Also, the first measurement unit 10 may measure the first parameter and the second measurement unit 20 may measure the second parameter at the same time.

As described above, the infection risk measurement system 1 according to this embodiment includes a first measurement unit 10, a second measurement unit 20, a determination unit 30, and an output unit 50. The first measurement unit 10 measures a first parameter, which is a parameter corresponding to the amount of adenosine triphosphate or the amount of adenosine triphosphate. The second measurement unit 20 measures a second parameter, which is a parameter corresponding to the amount of a component contained in a human body fluid or the amount of the component. The determination unit 30 refers to the reference data and determines the infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured by the first measurement unit 10 and the value of the second parameter measured by the second measurement unit 20 for the test sample. The reference data is assigned an infection risk level in advance for each combination of the value of the first parameter and the value of the second parameter. The test sample is collected from the surface of the measurement target location. The output unit 50 outputs the determination result determined by the determination unit 30.

The infection risk measurement method according to this embodiment also includes a step of measuring a first parameter, which is an amount of adenosine triphosphate or a parameter corresponding to the amount of adenosine triphosphate. The method includes a step of measuring a second parameter, which is an amount of a component contained in human body fluid or a parameter corresponding to the amount of the component. The method includes a step of referring to reference data and determining an infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured for the test sample and the value of the second parameter measured for the test sample. The reference data is assigned an infection risk level in advance for each combination of the value of the first parameter and the value of the second parameter. The test sample is collected from the surface of the measurement target location. The method includes a step of outputting the determined determination result.

In this way, the infection risk measurement system 1 and the infection risk measurement method use the first parameter and the second parameter to determine the infection risk. The first parameter is an index for evaluating the amount of microorganisms adhering to the surface of the measurement target location, and the second parameter is an index for evaluating the amount of body fluids adhering to the surface of the measurement target location. The saliva and nasal mucus of an infected person contain a large amount of viruses and bacteria, and if the test sample contains a large amount of saliva and nasal mucus, the values of the first parameter and the second parameter tend to be large. Therefore, by referring to the reference data and determining the infection risk level based on these parameters, it is possible to determine the infection risk of viruses that are not easy to determine by ATP swabbing alone. By measuring contaminated locations with a high infection risk, it is possible to prevent unnecessary sterilization work from being performed in locations such as the above-mentioned area E where the infection risk is low even if the ATP amount is high.

The infection risk measurement system 1 and the infection risk measurement method according to this embodiment are particularly suitable for use in places where multiple people enter and exit, such as hospitals, nursing homes, nurseries, kindergartens, schools, commercial facilities, factories, offices, and homes. In addition, the infection risk measurement system 1 and the infection risk measurement method are also suitable for evaluating whether sterilization using ozone or the like has been performed properly.

[Infection risk assessment system]
Next, an infection risk determination system 100 according to this embodiment will be described with reference to Fig. 1. The infection risk determination system 100 according to this embodiment includes an input unit 110, a determination unit 30, and an output unit 50.

The input unit 110 inputs the amount of ATP in the test sample collected from the surface of the measurement target area or the value of a first parameter which is a parameter corresponding to the amount of ATP. The input unit 110 also inputs the amount of a component contained in the human body fluid in the test sample or the value of a second parameter which is a parameter corresponding to the amount of the component. The input unit 110 may include a first measurement unit 10, and the value of the first parameter may be input by the first measurement unit 10. The input unit 110 may also include a second measurement unit 20, and the value of the second parameter may be input by the second measurement unit 20. The input unit 110 may also include a numerical input unit 40, and at least one of the value of the first parameter and the value of the second parameter may be input by the numerical input unit 40. The first measurement unit 10, the second measurement unit 20, and the numerical input unit 40 may be those described above.

The determination unit 30 refers to the reference data and determines the infection risk level of the measurement location based on a combination of the value of the first parameter input from the input unit 110 and the value of the second parameter input from the input unit 110. As described above, the reference data is assigned an infection risk level in advance for each combination of the value of the first parameter and the value of the second parameter. The determination unit 30 can use the above-mentioned data.

The output unit 50 outputs the judgment result judged by the judgment unit 30. The output unit 50 may be one as described above.

The infection risk determination system 100 according to this embodiment can determine the risk of virus infection, similar to the infection risk measurement system 1.

The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples.

[Reference Example 1]
First, 5 g of sodium chloride, 0.5 g of yeast (instant dry yeast, manufactured by Saf Co., Ltd.) and 450 mL of ion-exchanged water were placed in a container and stirred to dissolve the sodium chloride. After that, this solution was transferred to a graduated cylinder and the solution was made up to 500 mL with ion-exchanged water to prepare a saliva simulant. It is assumed that the saliva dispersed as droplets has low viscosity and contains a large amount of water. In other words, since it is assumed that the number of bacteria contained in the droplets is less than the total number of bacteria in the mouth, the amount of yeast in the saliva simulant is prepared to be about 1/10 to 1/1000 of the total number of bacteria in the mouth of an average person. Next, a predetermined amount of the saliva simulant was sprayed on a plastic plate and dried to be the measurement target. These are shown in Table 1 as Reference Examples 1-1 to 1-4.

[Reference Example 2]
First, a predetermined amount of the saliva simulant was sprayed onto a plastic plate and allowed to dry, similar to Reference Example 1. Next, the area where the saliva simulant was sprayed was wiped with a cloth soaked in ethanol (EtOH) or hypochlorous acid (HClO) to be used as the measurement area. These are shown in Table 2 as Reference Examples 2-1 to 2-5.

[Reference Example 3]
The inside of disposable rubber gloves that had not been used or had been worn for a certain period of time were used as the measurement target areas. These are shown in Table 3 as Reference Examples 3-1 to 3-7.

[Reference Example 4]
The palms of the hands before and after hand washing were used as the measurement sites. These are shown in Table 4 as Reference Example 4-1 to Reference Example 4-3.

[Reference Example 5]
The handrails of the stairs were used as the measurement points. These are shown in Table 5 as Reference Examples 5-1 to 5-8.

[Reference Example 6]
First, 0.5 g of yeast (instant dry yeast, manufactured by Saf Co., Ltd.) and 450 mL of ion-exchanged water were placed in a container and stirred. The liquid was then transferred to a graduated cylinder and the graduated volume was increased to 500 mL with ion-exchanged water to prepare a bacterial solution. The amount of yeast in the bacterial solution was adjusted to be about 1/10 to 1/1000 of the total number of bacteria in the saliva of an average person. Next, 1 mL of the bacterial solution was sprayed onto a plastic plate and dried, which was used as the measurement target area. These are shown in Table 6 as Reference Example 6-1 to Reference Example 6-2.

[Reference Example 7]
The measurement targets were the desks that had been wiped before wiping or after spraying with sodium hypochlorite (NaClO) or ethanol (EtOH). These are shown in Table 7 as Reference Examples 7-1 to 7-21.

[Reference Example 8]
The dining table was used as the measurement target location. These are shown in Table 8 as Reference Example 8-1 to Reference Example 8-2.

(ATP swab test)
For Reference Examples 1 to 2 and Reference Examples 6 to 8, a 10 cm x 10 cm frame was placed on the measurement target location, and the surface of the measurement target location within the frame was wiped with a cotton swab for ATP wipe test. For Reference Examples 3 to 5, the surface of the measurement target location was wiped with a cotton swab for ATP wipe test so that the wiping area was 100 cm ^2. The wiped cotton swab was inserted into a measurement tube containing an ATP measurement reagent (3M ^™ Clean-Trace ^™ UXL100) and shaken to react the wiped measurement target with the reagent. Next, the measurement tube into which the cotton swab was inserted was set in an ATP measurement device (luminometer) (3M ^™ Clean-Trace ^™ NG), and the luminescence (RLU: Relative Light Unit) of the measurement target was measured. As described above, the amount of luminescence (RLU) is proportional to the amount of ATP, and therefore, in this discussion, the amount of luminescence (RLU) is regarded as the amount of ATP.

(conductivity)
For Reference Examples 1 to 2 and Reference Examples 6 to 8, a 10 cm x 10 cm frame was placed at a position different from the position where the frame was placed in the ATP wipe test, but close to the position where the frame was placed in the ATP wipe test. Next, absorbent cotton soaked in water (Amethyst (registered trademark) Mom and Baby Water Only Cotton, Taiei Co., Ltd.) was held with tweezers and the surface of the measurement target area within the frame was wiped. For Reference Examples 3 to 5, the surface of the measurement target area was wiped with absorbent cotton soaked in water so that the wiping area was 100 cm ^2. Next, using two tweezers, the absorbent cotton was squeezed with the surface that was used to wipe the measurement area facing down, and the obtained few drops of water were measured with an electrical conductivity meter (LAQUA (registered trademark) twin EC-33B, manufactured by Horiba, Ltd.). In this device, the conductivity is measured by an AC two-electrode method and converted to conductivity at 25 ° C.

Tables 1 to 8 and Figures 4 to 9 show plots of the relationship between the ATP amount (RLU) and conductivity (μS/cm) for the reference examples obtained as described above. The X-axis of the graphs shows the ATP amount (RLU) and the Y-axis shows the conductivity (μS/cm) in common logarithms. Similarly, the ATP amount (RLU) and conductivity listed in each table are also shown in common logarithms.

As shown in Table 1 and FIG. 4, the test sample of Reference Example 1 had an ATP of Log ₁₀ 3 RLU or more and a conductivity of Log ₁₀ 2 μS/cm or more. The area where Reference Example 1 is plotted is considered to be an area where the amount of saliva attached to the measurement target area is large and the risk of infection is high. In addition, it is expected that infected people have a lowered immune system, and there are more microorganisms in their body fluids than in the saliva simulant, resulting in a large amount of ATP. Therefore, the area where Reference Example 1 is plotted and the area with a higher amount of ATP than Reference Example 1 were set as Area A, which is likely to be contaminated by saliva droplets and is considered to have the highest risk of infection.

On the other hand, as shown in Table 2 and Figure 4, the test sample of Reference Example 2 had an ATP of less than Log ₁₀ 4.5 RLU and a conductivity of less than Log ₁₀ 2 μS/cm. These results show that even if the saliva simulant adheres to the plastic plate, it can be removed by wiping. Therefore, the area where Reference Example 2 is plotted was set as area C, which is considered to have been cleaned.

As shown in Table 3 and Figure 5, the inside of a glove that has been worn for a certain period of time tends to have a higher ATP amount value compared to the inside of an unused glove. Also, as shown in Table 4 and Figure 5, the palm has the same ATP amount and conductivity as the inside of a glove that has been worn for a certain period of time. Therefore, the area where Reference Example 3 and Reference Example 4 are plotted was set as Area B, which is considered to be likely to be frequently touched by people.

As shown in Table 5 and Figure 6, Reference Example 5 had a lower amount of ATP than Reference Examples 3 and 4, excluding unused gloves. Since few people talk on the stairs, it is thought that there is little contamination by saliva droplets. In addition, since the staircase handrails are cleaned every day, it is thought that there is little human contact. Therefore, the area where Reference Example 5 is plotted was set as Area D, which may be contaminated by saliva droplets or human contact, but time has passed since contamination and the virus activity is thought to have decreased.

Although not shown, it has been confirmed that the ATP amount decreases over time even in test samples that are plotted in area A or area B. This is thought to be because microorganisms such as bacteria produce ATP when they grow, but after the microorganisms die, no ATP is produced and the ATP is simply broken down by enzymes remaining in the cells.

As shown in Table 6 and Figure 7, the test sample of Reference Example 6 had an ATP of Log ₁₀ 4.5 RLU or more and a conductivity of Log ₁₀ 2 μS/cm or less. It is considered that the plastic plate coated with the bacterial liquid has little virus adhesion, not dirt derived from human body fluids. Therefore, the area where Reference Example 7 is plotted was set as Area E, where the possibility of the presence of microorganisms is high, but the possibility of contamination derived from humans is considered to be low.

As shown in Table 7 and Figure 8, the disks before wiping were plotted in area A or area B. However, as shown by the arrows in Figure 8, the disks after wiping with sodium hypochlorite or ethanol showed reduced ATP levels and conductivity, and tended to be plotted in area C.

As shown in Table 8 and Figure 9, Reference Example 8-1 was classified as Area C, while Reference Example 8-2 was classified as Area A. The dining table in Reference Example 8-1 was cleaned, lowering the risk of infection, whereas the dining table in Reference Example 8-2 was subject to saliva splashing due to conversation, presumably increasing the risk of infection.

As explained above, the infection risk level can be determined by measuring the first parameter and the second parameter and referring to the created reference data. This shows that the infection risk measurement system, infection risk determination system, and infection risk measurement method make it possible to determine the risk of viral infection.

Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they are mutually inconsistent.

This disclosure can contribute, for example, to Goal 3 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Ensure healthy lives and promote well-being for all at all ages."

REFERENCE SIGNS LIST 1 infection risk measurement system 10 first measurement unit 20 second measurement unit 30 judgment unit 40 numerical input unit 50 output unit 100 infection risk judgment system 110 input unit

Claims (5)

A first measurement unit that measures a first parameter which is an amount of adenosine triphosphate or a parameter corresponding to the amount of adenosine triphosphate;
A second measurement unit that measures a second parameter, which is an amount of a component contained in a human body fluid or a parameter corresponding to the amount of the component;
a determination unit that refers to reference data in which an infection risk level is previously assigned for each combination of the value of the first parameter and the value of the second parameter, and determines the infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured by the first measurement unit and the value of the second parameter measured by the second measurement unit for a test sample collected from the surface of the measurement target location;
an output unit that outputs a determination result determined by the determination unit;
Equipped with
the parameter corresponding to the amount of adenosine triphosphate is at least one of the amount of luminescence due to the action of luciferase and the concentration of adenosine triphosphate;
the parameter corresponding to the amount of the component is at least one of electrical conductivity and ion concentration;
An infection risk measurement system, wherein the component is a protein contained in human saliva . 2. The infection risk measurement system of claim 1, wherein the value of the second parameter of the test sample is corrected according to at least one of the ambient temperature and ambient humidity of the measurement target location, and the determination unit determines the infection risk level based on a combination of the value of the first parameter measured by the first measurement unit for the test sample and the corrected value of the second parameter. 3. The infection risk measurement system of claim 1, wherein an infection risk level is pre-assigned to the reference data for each combination of the surface material of the measurement target area, the value of the first parameter, and the value of the second parameter, and the determination unit refers to the reference data and determines the infection risk level according to the material. an input unit for inputting the amount of adenosine triphosphate in a test sample collected from the surface of a measurement target location or the value of a first parameter which is a parameter corresponding to the amount of adenosine triphosphate, and the amount of a component contained in a human body fluid in the test sample or the value of a second parameter which is a parameter corresponding to the amount of the component;
a determination unit that refers to reference data in which an infection risk level is pre-assigned for each combination of the value of the first parameter and the value of the second parameter, and determines an infection risk level of the surface of the measurement target location based on the combination of the value of the first parameter input from the input unit and the value of the second parameter input from the input unit;
an output unit that outputs a determination result determined by the determination unit;
Equipped with
the parameter corresponding to the amount of adenosine triphosphate is at least one of the amount of luminescence due to the action of luciferase and the concentration of adenosine triphosphate;
the parameter corresponding to the amount of the component is at least one of electrical conductivity and ion concentration;
An infection risk determination system, wherein the component is a protein contained in human saliva . Measuring a first parameter, the first parameter being the amount of adenosine triphosphate or a parameter corresponding to the amount of adenosine triphosphate;
measuring a second parameter, the second parameter being the amount of the component in the human body fluid or a parameter corresponding to the amount of said component;
A step of referring to reference data in which an infection risk level is pre-assigned for each combination of the value of the first parameter and the value of the second parameter, and determining an infection risk level of the surface of the measurement target location based on a combination of the value of the first parameter measured for a test sample collected from the surface of the measurement target location and the value of the second parameter measured for the test sample;
A step of outputting the determined result;
Including,
the parameter corresponding to the amount of adenosine triphosphate is at least one of the amount of luminescence due to the action of luciferase and the concentration of adenosine triphosphate;
the parameter corresponding to the amount of the component is at least one of electrical conductivity and ion concentration;
The method for measuring infection risk, wherein the component is a protein contained in human saliva .

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