BIOAEROSOLS

Matt Tribby

ENV 6131 Aerosol Mechanics

March 29, 2012

http://en.wikipedia.org/wiki/Sneeze

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Overview

History Definition and classifications Health effects Transmission Bioaerosol as weapons Sampling methods Protection Methods

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Definition of Bioaerosol

An aerosol of biological origin, including viruses, viable organisms such as bacteria and fungi and products of organisms such as fungal spores and pollen (Hinds pg. 4)

Emphasis usually given on viability of bioaerosol

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Bioaerosols In History Irish Potato Famine (1845-1852)

Roughly 1 million people died due to starvationAnother 2 million emigrated from IrelandAt time of famine 1/3 of population was entirely

dependent on potatoes for foodPhytophthora infestans fungus contributed to

death of potato cropBrought in from ships and distributed via wind

http://aerosol.ees.ufl.edu/Bioaerosol/Section05.html

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Bioaerosols In History Bubonic Plague (Black Death) (1348-1350)

Estimated to have killed 30-60% of Europe’s population

Reduced world’s population from 450 million to around 375 million

Disease originated from fleas and was carried by rats

Yersinia pestis bacteria was cause of disease

http://en.wikipedia.org/wiki/File:Blackdeath2.gif

http://aerosol.ees.ufl.edu/Bioaerosol/Section06.html

Why was the Black Death able to travel through Europe so quickly?

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Bioaerosols In History Influenza Epidemic of 1918

Estimated to have killed nearly 50 - 100 million people

Afflicted more than 25% of the US population

Average life expectancy in US dropped by 12 years

3% of the global population died, with nearly 500 million (27% global population) being infected

http://www.archives.gov/exhibits/influenza-epidemic/What are some diseases associated with bioaerosols in present day?

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Bioaerosols as weapons

Capable of being used for biological warfare

Growing concern for uses from terrorist groups

Anthrax scare in US in 2001 example

http://news.bbc.co.uk/2/hi/americas/1590903.stm

http://www.ph.ucla.edu/epi/bioter/detect/antdetect_intro.html

Why are bioaerosols as biological weapons more dangerous in present day compared to 100 years ago?

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Classifications

MicroorganismsProkaryotesEukaryotes

Fungi Viruses

http://www.kimkinservik.com/category/real-estate/

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Microorganisms - Prokaryotes

One of the simplest living organisms Lack a nucleus Most prevalent form is bacterium

Size range from 0.3 – 100 µmConcentrations of 0.5 – 1000 airborne

bacteria per cubic meter of ambient air Some forms release spores which can

survive for long periods of time

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Prokaryote Diagram

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Microorganisms - Eukaryotes Exist as microorganisms such as fungi

and protozoa, and highly complex organisms such as plants and animals

DNA located in the nucleus Contain extra organelles

Mitochondria – animalsChloroplasts – plants

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Eukaryote Diagram

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Fungi

Eukaryotic, non-vascular microorganisms Reproduce via spores, usually dependent on

wind dispersion Both sexual (meiotic) and asexual (mitotic)

spores can be produced Have alternation of generations

Can you name any foods made with fungi?

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Fungi Diagram

http://www.amergeo.com/Papers/Fungus.htm

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Viruses

DNA strand inside of a protein capsule Not self-sustaining entities

Require a host to survive and are not able to carry out metabolic processes

Very small size range (20-300 nm) Small size makes difficult to sample and deep

penetration into respiratory tract

Why can’t viruses be treated with antibiotics?

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Virus Diagram

http://www.csa.com/discoveryguides/avian/review2.php

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Health Effects Can produce a wide range of effects Bioaerosols have to be viable in order to be

infectious Non-viable can cause allergies or toxic

reactionsAllergies estimated cost economy nearly $7

billion annuallyEstimated 30.2 million people in United States

have been diagnosed with asthma

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Non-Viable Example: Gulf Coast Red Tide Blooms in Gulf

Coast cause many allergic reactions each year

Algae release toxins due to energy from waves – released as non-viable aerosols

Cause extreme eye and respiratory irritationRespiratory tract can constrict

when in contact with toxins, causes difficulties in breathing

http://start1.org/red-tide/

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Diseases associated with Bioaerosols

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Transmissions Methods

Methods vary depending on the type of bioaerosol Dependent on viability

Transferred through natural methodsWind, Oceans

Transferred through interactionsPeople, Animals

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Pathogenic Transmission

Occurs through several routesPerson to personWaterborneFoodborneVector-borneAirborneCombination of the above

Can you name a disease that incorporates a combination of the above routes?

How can our body’s defense mechanisms actually cause additional harm?

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Indoor Dangers Many sources to bioaerosols found indoors

DustPetsOrganic Wastes

Building’s circulation of air also can contribute to contamination on multiple floors

http://aerosol.ees.ufl.edu/Bioaerosol/Section07.html

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Air Circulation Dangers Buildings that rely on re-circulated air pose

large threat Ductwork within buildings can provide

moist environment and protection from natural inactivation methods

Any areas in a home or building that may have higher concentrations of bioaerosols than others?

http://www.homeairlv.com/air-conditioning/air-conditioning-duct-work/

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Sampling Methods Sampling method needs to be efficient in

three categoriesInlet efficiencyPhysical collectionBiological collection

Population can be classified through multiple methodsMass conc., Number conc.

Viability of bioaerosol crucial in determining the infectivity

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Sampling Methods

Viable bacteria and fungal spores form colonies (CFU)

Viable viruses form plaques on their host cells (PFU)

Preserving the viable count is needed to maintain high biological collection efficiency

What is another aspect to sampling that must be considered when dealing with viability?

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Impaction Utilize bioaerosol inertia to collect onto a

solid or semi-solid collection medium If inertia too large then it will not follow air

flow lines Once collected can be cultivated to

determine viable count Physical collection highly dependent on

particle size

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Types of Impaction

Slit impactorsImpact particles directly onto culture

medium Agar is collection medium for bacteria and

fungal sporesAgar is semisolid material containing water

and nutrients that allow growth Cell or tissue media used for collection of

virusesWhy aren’t viruses collected on agar media only?

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Types of Impaction Multijet impators

Typically have 100-500 jets impacting directly onto agar culture plates

Spreads collected particles to many locations to prevent overload

Single and multistage available with cutoff diameters from 0.6 – 8 µm

Site with a colony known as filled site or positive hole

Plates analyzed by counting number of filled sites

What could be a potential problem associated with this method of collection?

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𝑛𝑐=𝑛𝑓 ( 1.0751.052− 𝑓 )

0.483for f < 0.95nf = number of filled sites with coloniesf = fraction of sites with colonies (nf/Nj)nc = total number of viable organisms collected

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Can a trend be associated with the correction factors?

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Impingers

Use liquid media for collection Inertia used to physically collect

bioaerosols along with diffusion

http://aerosol.ees.ufl.edu/Bioaerosol/Section09-3_answer.html#93

Would an impactor or impinger be more appropriate for airborne virus sampling?

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Filters

Use inertia and diffusion for collection of bioaerosols

Have high physical collection efficiency for a wide range of particle sizes

Challenges with extraction

How can filters be summarized in regards to efficiencies?

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Sampling Time

Need to contain a suitable number when collecting viable bioaerosols

Surface density of one colony per cm2 is usual goal

Times can vary depending on the environment of collection

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Sampling Time calculation

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How long should an outdoor aerosol sampling time be if the aerosol flow rate is 28 L/min, an average number concentration of bioaerosol particles of 150 CFU/m3 and the area of the collection media is 75 cm2?

How does the sampling time change when the environment is changed to an indoor livestock structure with an average number concentration of bioaerosol particles of 105 CFU/m3?

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http://water.me.vccs.edu/courses/env108/lesson9.htmhttp://water.me.vccs.edu/courses/ENV195Micro/lesson7_5.htm

What is the problem between the two petri dishes?

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Other Quantifying Methods Real-time polymerase chain reaction (RT-

PCR/qPCR)Used to amplify and quantify a targeted DNA

moleculeAllows detection and quantification for one or

more specific sequences in a DNA sample

http://www.langfordvets.co.uk/lab_pcr_mdu.htm

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Protection Methods Classified as either personal or collective

Personal – individualCollective – large scale

Respirators used for personal protectionSelf-contained breathing apparatus (SCBA)

Gloves, hand-washing and changing of clothes Antibiotics for bacteria, vaccinations for viruses UV units added to central air systems Filtration and electrostatic precipitators (ESPs)

used in central air to prevent distribution Would the mass distribution of the influenza vaccine be a personal or collective protection?

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Research Determining the viability of influenza

bioaerosols with different parametersRelative HumidityAbsolute HumidityTemperature

Effects of collection methods on viability of bioaerosols

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Facts of Influenza Typical size range of 80 – 120 nm Many variations

H1N1H5N1

Research has shown that virus most viable in low temperature, low relative humidity environments

What season would influenza tend to have the most outbreaks?

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Facts of Influenza

Still a lot of uncertainty as to viability and contraction of disease in aerosol form

Some studies contradict traditional thoughts More research is needed to fully understand

influenza’s effects on people determined by varying environmental conditions

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Tamerius et al (2011)

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Summary Bioaerosols are aerosols of biological origin

BacteriaVirusPollen

Many health effects can be seen from interactions with bioaerosols

History has shown that some bioaerosols can be global killers

Different sampling methods used for collectionContamination and viability given focus

Still a lot unknown about characteristics

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Reflections