sign in sign up
<<
Home , Airborne transmission, Melioidosis

Breaking the Chain of Stephanie Bozigian-Merrick, BSN, RN, NHDP-BC MRC Volunteer

1 The Chain of Infection

2 To stop the spread of infection, break any link in the chain!

3 The First Link: The

Viruses Rickettsiae Fungi Parasites Prions

4

• Genetic material in a protein sheath • Not a cell; not really alive • Viruses hijack cells and inject their genetic material • The host cell is converted into a replicator • Eventually the host cell bursts, releasing countless new virus particles Background created by brgf 5 The Virus in Action

Viruses injecting their genetic material into bacteria (Microbiology Online) A host cell ruptures, releasing replicated influenza viruses (Wikipedia) 6 • • Viral Hemorrhagic • , Mumps, • SARS and MERS Examples of • HIV viral • The Hepatitides • RSV • Poliomyelitis • Rabies

7 don’t work

Some viruses respond to antiviral medications like oseltamivir, ribavirin, or More about AZT

viruses Some viruses persist in the environment for a very long time

The most likely MCM we will dispense at an EDS for a viral is…

8 Vaccine

9 Bacteria

CDC 10 Bacteria • Single-celled life forms with cell walls and DNA but no nucleus • Wide range of sizes, shapes, and behavior • Can sometimes be eliminated with antibiotics • Bactericidal – kills the bacteria • Bacteriostatic – keeps the bacteria from reproducing • The must be effective against the particular bacteria • Bacteria replicate and evolve very quickly, easily developing antibiotic resistance • Some bacteria form spores so that they can survive in

hostile environments 11 • • Bacterial meningitis • Anthrax Examples of • Bacterial • Diseases • , Melioidosis, • Pertussis • Tetanus

12 Bacterial spores are very hardy

More about Some bacteria produce bacteria toxins

We would most likely dispense antibiotics and vaccines at our EDSs

13 Rickettsiae

CDC 14 Rickettsiae

• Tiny intracellular organisms • Most rickettsial diseases are zoonotic and are transmitted to humans via arthropod vectors • Diagnosis may be very complex and difficult; treatment may be long

15 • •Babesiosis, , Examples of rickettsial •Rocky Mountain Spotted diseases • •

16 More about Rickettsiae

• Rickettsiae don’t make their own ATP like other “cells” do. They steal ATP parasitically from the cells in which they live. • They can’t be grown in culture medium like bacteria – that’s one of the reasons rickettsial disease is hard to diagnose. • Almost all rickettsial disease causes rash in affected humans, except for Q fever • First-line treatment = CDC 17 Fungi, yeasts and molds

CDC

18 Fungi

• Simple, ubiquitous organisms that produce spores • Feed on organic matter in their environment • Fungi are necessary for decomposition • Fungi often compete with bacteria for local resources • Superficial fungal = usually not dangerous • Systemic/internal fungal infections = sometimes deadly 19 • Candidiasis • Histoplasmosis • Mucormycosis Examples of • Coccidioidomycosis Fungal • Cryptococcus neoformans Diseases • Pneumocystis carinii • Aspergillosis • Other diseases ending in “mycosis”

20 Many fungi Immuno- Anything Some produce compro- that bioweapons More toxins that mised eliminates are derived are deadly people are bacteria from fungi, about to humans at greater gives the especially Fungi risk for fungi a those fungal chance to designed to disease flourish impact the food supply

21 Parasites

• WIDE RANGE of size, complexity, habits • Parasites live by taking what they need from their host • Most parasites don’t benefit by killing their hosts • Parasites are often species-specific – • inside members of other species, they get lost • Brain tissue and eye tissue make popular destinations for animal parasites inside humans

22 Neurocysticercosis Live pork tapeworms ingested by humans often wind up in the brain

Nutritionfacts.org Neurocysticercosis is the most common cause of acquired epilepsy in developing countries

23 Endoparasites – Protozoans

Naegleria fowleri, “the brain-eating ” Primary amoebic meningoencephalitis -- CDC

G. Lamblia – protozoan causing Giardiasis CDC Entamoeba histolytica, eating the lining of a small intestine CDC24 CDC New World Screwworm “maneater” CDC Multi-celled endoparasites 25 Some ectoparasites are harmless nuisances…

liceclinicsofamerica.com26 and some are vectors of deadly diseases. CDC 27 Often have complex life cycles requiring several different hosts

Generally do not kill their host on purpose (c.f. “parasitoid” or “predator”) Parasites

Often bring us other

Extra credit: do you have to be a parasite to be a vector? 28 • Little scraps of • Prion diseases are protein that can contracted by eating recode genetic infected CNS tissue material • Prion disease may • Causative agent of take decades to • BSE – Mad Cow manifest Disease • You can’t kill prions by Prions • CJD – cooking, even at high Creutzfeldt-Jakob temps for long periods Disease • Prions may someday • Scrapie – animal make diabolical brain disease bioweapons • Kuru – human brain disease 29 So how do we break the pathogen link?

Remove or Kill Incapacitate sequester Kill the pathogen Incapacitate the Remove or – antibiotics, pathogen/stop sequester the antivirals, replication – pathogen – disinfectants, bacteriostatic biohazard waste, heat agents, fever burning, burial

30 The Second Link: The Reservoir

31 •Where pathogens hang out •Can be a location, an environment, a The population of animals Reservoir •In the case of some EIDs, the reservoir can be a human or a group of humans (e.g., smallpox)

32 33 Milwaukee, 1993 • Outbreak of cryptosporidiosis • Failure of water treatment system to remove oocysts in water from Lake Michigan • Over 100 fatalities; thousands of people with symptoms • Reservoirs: • Lake Michigan • City drinking water supply 34 Mary Mallen – of S. typhi

35 So how do we break the reservoir link?

Eliminate Isolate Treat

Eliminate the Isolate the Treat the reservoir reservoir from the reservoir – altogether – “cats at-risk population vaccine baiting for to eat the rats,” – Mary Mallen raccoons; reservoir for VHFs filtration of water in South America supplies

36 The Third Link: The Portal of Exit (How the pathogen gets out of the reservoir)

Wikipedia

37 • Specific to the reservoir • Coughing, sneezing, bleeding, breathing, defecating/urinating etc. • The bite of a vector species • Humans intentionally tapping the Portals of Exit reservoir for resources • Mechanical failure (e.g., faulty filtration; wet mask; ruptured can) • “Acts of God” • Harvey and the lagoons

38 39 John Snow and – London, 1854 Wikipedia 40 Engineering Controls to prevent E. coli from sloshing UCDavis out of the lagoon

41 USDA So how do we break the Portal of Exit link?

Block/Contain Remove Access Eliminate

Block the Prevent humans Eliminate egress pathogen as it from accessing of pathogen from leaves the contents of reservoir – spill reservoir – cough reservoir – pump prevention etiquette handle

42 The Fourth (and most critical) Link: Routes of (how the pathogen gets to its next victim)

43 •Direct Contact •Indirect Contact •Droplet Routes of •Waterborne Transmission •Foodborne •Bloodborne •Airborne •Vectorborne

44 You physically contact Direct Contact the infected person: •Touching •Kissing •Sexual contact

…and the pathogens move from the infected person to you openclipart.com

45 Sample “Direct Contact” Infection: Scabies

46 Preventing Direct Contact Transmission

Avoid Contact Use Barriers (PPE)

No handshaking Used PPE is contaminated and No hugging must be discarded before it No skin-to-skin contact contaminates you or anyone of any kind! else DOFF PPE WITH GREAT CARE!

47 Indirect Contact

You touch something that the infected person has touched Objects that can harbor pathogens are called

Many pathogens can persist for hours or days on fomites

ALMOST EVERY PATHOGEN CAN BE TRANSMITTED BY INDIRECT CONTACT!

48 •Pens and pencils •Door and faucet handles •Keyboards Examples of •Toys and furniture Fomites •Cell phones •Cutting boards •Litterboxes •Used tissues

49 Preventing Indirect Contact Transmission

Disinfect Avoid fomites Offer sanitizer fomites

Avoid touching Clean and Provide hand potential fomites disinfect fomites sanitizer for to the extent frequently people using possible fomites (e.g., pens)

50 The pathogen Coughing reaches you Sneezing Vomiting, through a spray etc. of droplets Splashing Droplet You inhale the droplets Transmission

The droplets land on your mucous membranes

51 Preventing Droplet Transmission

Block spray Keep clear Avoid splashing

Use masks, Stay at least 6 feet Perform tissues, cough away from people procedures etiquette who are coughing carefully techniques or sneezing

52 • Scientists debate about the classification of some respiratory illnesses NB: Droplet • Influenza – droplet or airborne??? • Anything that creates an can Transmission create a droplet pathogen is tricky! • Suctioning, irrigating wounds, blowback, hand dryers, flushing • Droplets that land on surfaces/fomites can spread germs via indirect contact

53 You are exposed to the pathogen by Waterborne • Drinking the water Transmission • Using the water for personal care tasks such as bathing, brushing teeth • Engaging in recreational activities – swimming, boating, hot tubbing etc. • Using contaminated water to wash dishes, equipment • Inhaling the water via Neti- Pot or humidifier

Wikipedia 54 • Cholera • Giardiasis • Dracunculiasis Examples of • Legionnaires’ disease Waterborne • Cryptosporidiosis Diseases • Schistosomiasis • Primary amoebic meningoencephalitis • E. coli or other enteritis

55 Preventing Waterborne Transmission

Treat before Avoid Treat at source use

Don’t drink or Assess and repair , filter or otherwise use water supply chemically treat contaminated purification water for personal water use as appropriate

56 Foodborne Transmission

• You eat something containing the pathogen • The pathogen got into your food via • Cross-contamination • Intentional contamination • Inadequate, inappropriate preparation • Poor hygienic practices by food handlers • Food spoilage/inadequate food storage practices • Contamination of food before purchase • Viruses, bacteria, fungi, parasites and prions can all be

foodborne 57 • Enteritis – E. coli, C. jejuni, S. typhus • Parasites – Trichinellosis, Examples of neurocysticercosis • Ergot or trichothecene poisoning Foodborne • toxin ingestion Diseases • , rotavirus, Hep A • Anthrax, • BSE

58 Preventing Foodborne Transmission

Proper No Second Rule Game = germs handling

Prepare and store Don’t eat food Treat game and all food properly that hits the floor. animal products Ever. as if they are contaminated

59 Bloodborne Transmission

• You are exposed when infectious blood or body fluids get into your body • Unprotected sex • Prenatal exposure • Shared needles; needlesticks

[email protected] • Through breaks in skin or through mucous membranes • Transfusions

60 •HIV •Ebola and other VHFs Examples of •Hepatitis B, C, etc. Bloodborne •Malaria Diseases • •Zika

61 Preventing Bloodborne Transmission

Barriers Screening No sharing

Bloodborne Screen blood needles precautions as supply, per OSHA and pregnant CDC women etc. instruments

62

• The pathogen hangs in the air for extended periods • Everyone in the area is exposed • Airborne diseases: • Measles CDC • Tuberculosis • Smallpox 63 Preventing Airborne Transmission

Control air Isolate High-level PPE flow Isolate and Negative Adequate, cohort pressure properly fitted infected rooms, HEPA PPE, safely people filtration removed 64 “POD” suitable for preventing airborne transmission

ABC 65 Vectorborne Transmission

• The pathogen is conveyed to you by another entity • Arthropods • Other animals • Vectors can bring you • Viruses • Bacteria • Rickettsiae • Parasites/protozoans

66 • Malaria • Most rickettsial illness Examples of • Dengue, Chikungunya • West Nile Virus Disease, EEE Vectorborne • Chagas disease Diseases • Leishmaniasis • Rabies • Plague

67 Preventing Vectorborne Transmission

Eliminate Prevent Bites Treat

Rid the Prevent Medicate environment vectors from vectors to of the biting – nets, incapacitate vector(s) bug spray, in or kill the by dusk pathogen

68 The Portal of Entry is the way the pathogen gets into your body

The Fifth Link: The Portal of Entry

yourdictionary.com69 Most of the time, pathogens DON’T get in… We each have an efficient barrier that keeps any arriving pathogen from getting inside our bodies… Our skin!

70 • The skin is damaged or broken • Burns • Chapping • Dryness Skin is a near- • Rashes foolproof line • Abrasions or other breaks in the of defense, skin unless… • Maceration (waterlogging) • The skin is breached by a vector or • The pathogen lands on mucous membranes 71 To break the Portal of Entry link in the chain…

Care for your Protect mucous DON’T TOUCH skin membranes Take good care Use appropriate your eyes, nose, of your skin! barrier PPE – mouth, or other Keep it in tip- face shields, mucous membranes top condition! goggles, masks, unless you have BEWARE OF condoms etc. JUST washed your SHARPS! hands thoroughly!

72 The pathogen must reach someone who The Sixth Link: The is susceptible in order to Susceptible Host produce disease

73 • Genetic “Immunity” and Natural Selection • Active or passive immunity – your body recognizes and destroys the pathogen • Active immunity – previous illness or Strategy #1 -- • Passive immunity – receipt of someone Immunity else’s antibodies • Prenatally or via colostrum • Via antitoxin administration or treatment with convalescent serum • – pathogen can’t get a foothold in the population 74 Strategy #2 -- Resistance

OPTIMAL ADEQUATE STRESS NUTRITION SLEEP/REST MANAGEMENT

75 Strategy #3 -- Avoidance

•People with disadvantages may need to avoid any exposure to pathogens

•They may be advised to employ social Glutenfreetherapeutic s.com distancing during outbreaks •Some people require protective or reverse precautions

76 Strategy #4 – “Cocooning”

People with whom the vulnerable person must interact are all vaccinated (e.g., pertussis vaccine for infants’ family members)

Everythingsilkworm.com.au

77 Strategy #5 – Pre- or Post-Exposure Prophylaxis When a susceptible person may soon experience an exposure – Pre-Exposure Prophylaxis may prevent development of the disease

After a susceptible person has been exposed – Post- Exposure Prophylaxis may prevent development of the

HIVplusmag.com disease 78 When you administer post-exposure prophylaxis at an EDS, you are breaking the Chain of Infection!

Freepik

79 Special Bonus Slide: Zoonotic Diseases • A zoonotic disease (“”) is one that came from animals. • Humans may be accidental or incidental victims. • Animal pathogens sometimes “get lost” inside human bodies… • They wind up in unexpected places (e.g., toxocariasis) • They often have multiple routes of transmission (e.g., tularemia) • You and your pets can often share zoonotic diseases 80 University of Guelph