加藤研究室・大岡研究室・菊本研究室Kato Lab., Ooka Lab., and Kikumoto Lab.

Establishing quantitative evaluation method of contact infection risk using qPCR method

Background /Purpose

1/2

= ＋

Real-time PCR Thermal cycler MonitoringFluorescent

substance

＋

Background

■ Increase of cities’ population and

Processing of building air in recent years

∴Elevation of infection risk→Need to control infection

■ The mechanism of contact infection is complicated (※1)

therefore, the evaluation method is not established yet

■ Development of gene analysis technology and

PCR(※2)method

・It is classified as three major infection routes among several infection routes.

(Air infection, droplet infection, contact infection)

・Frequent occurrence as typified by norovirus

・It is impossible to predict by CFD unlike air infection and droplet infection

・A method developed by Carrie-Maris in 1983.

・It makes analysis faster , accurate and easier. Among them, this

study used real-time PCR method is used in this study.

This is a method of monitoring the production process of a PCR

product using a fluorescent substance and measuring

(quantifying and detecting) the target DNA .(Below figure)

・Adenosine TriPhosphate (: ATP) method has been used as a

commonly used method until now, but this method is very difficult

to measure because it targets cells contained in all organisms.

Purpose

■Establishing quantitative evaluation method of contact infection

risk using qPCR method

・Establish analysis method

・Establish experimental method

■Creation of highly accurate infection simulator by combination

of behavior simulation and simulator (CFD) of other infection

route

※1 Contact infection ※2 PCR(Polymerase Chain Reaction) method

資料 :地理院地図

参考 : http://kansenyobou.net/

➢Infection

routeCharacteristic

Main causes

Microorganisms

Contact

infection

· Frequent propagation path that propagates

through fingers, foods and appliancesNorovirus

Droplet

infection

Coughing, sneezing, conversation, etc.,

propagate by droplet particles

It falls to the floor within 1 m.

It never keeps floating in the air

Influenza virus

Legionella spp.

Airborn

infection

Coughing, sneezing, etc. will propagate as

droplet nuclei.

Floating in the air, scattering by airflow

M. tuberculosis

加藤研究室・大岡研究室・菊本研究室Kato Lab., Ooka Lab., and Kikumoto Lab.

Establishing quantitative evaluation method of contact infection risk using qPCR method

Procedure / Result

2/2

Procedure BackgroundResult

Ap

ply

ing

Dry

ing

Sam

plin

g

·Tracer

・Drying time

・Sampling method

Decora

Float glass

Frosted glass

Lactic acid bacteria(Lactobacillus delbrueckii subsp. Bulgaricus OLL1073R-1)

Dilution rate× 10

× 100

× 1000

１’００”

２’３０”

４’００”

５’３０”

７’３０”

· Experimental location: Kato Laboratory Lab., The Univ. of Tokyo

Wipe off with uniform load three times in each direction

①

④

③

Store at -20 °C and analyze by qPCR method

Experimental flow and conditions in each step

Applying

amount

50μl

100μl

0

2

4

6

8

10

12

14

16

1(n=4)

2.5(n=3)

4(n=3)

5.5(n=5.5)

7.7(n=7.5)

Co

llect

ion

rat

e (%

)

Drying time(minuites)

Average

0

1

2

3

4

5

6

7

8

50(n=3) 100(n=4)

Co

llect

ion

rat

e (%

)

Applying amount(μl)

Average

0

0.5

1

1.5

2

2.5

3

3.5

10(n=4) 100(n=4) 1000(n=4)

Co

llect

ion

rat

e (%

)

Dilution rate

Average

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Float glass(n=4)

Frosted glass(n=4)

Decora(n=3)

Co

llect

ion

rat

e (%

)

Material name

Average

■Although the deviation was large in all cases, a large correlation with the collection

rate was not observed except for the drying time (④)

■As the collection rate has become very low as a whole, it will be a future task

・Material type

②

Examined the sampling rate when changing the conditions of ①-④

①Collection rate depend on dilution rate ②Collection rate depend on Applying amount

③Collection rate depend on material type ④Collection rate depend on drying time