OUTBREAK! Portrait of an Epidemic .

OUTBREAK!

Portrait of an Epidemic

http://phil.cdc.gov/Phil/details.asp

THE BLACK DEATH

• 25 million dead over 5 years

• One-third of Europe’s population

• “Victims often had lunch with their friends and dinner with their departed ancestors”

WHAT CAUSES DISEASE

• Basically, 4 causes:– Bacteria– Viruses– Parasites– Prions


BACTERIA

• Not all cause disease• Koch’s Postulates

– Show the bacterium is present in every case of the disease– Isolate the bacterium from the infected individual and grow it

outside the individual– Infect a healthy individual with the bacterium and have it produce

the same symptoms– Recover the bacterium from the newly sick individual


E. coli

Salmonella

http://www.lbl.gov/

commtechlab.msu.edu

www.nasa.gov www.geocities.com/avinash_abhyankar/

StreptococcusCauses strep throatRound

BorreliaCauses Lyme diseaseSpiral-shaped

phil.cdc.gov/Phil/

phil.cdc.gov/Phil/

www.uiowa.edu/~cemrf/

www.life.umd.edu/classroom/bsci424

Bacillus anthracis

phil.cdc.gov/Phil/details.asp

Viruses

• Not really alive?• Require host to

reproduce

www.nsf.gov/od/lpa/

Influenza Virus

Avian Influenza

phil.cdc.gov/Phil/

www.cdc.gov/ncidod www.aids-info.ch/bilder/schule_aids

phil.cdc.gov/Phil/details.asp

PARASITES

• Protists– Malaria– African sleeping

sickness

• Other parasites– Hookworms– Wuchereria bancroftii

phil.cdc.gov/Phil/

PRIONS

• Bits of self-replicating protein

• Mad cow disease• Creutzfeldt-Jakob• Spongiform

encephalitis

phil.cdc.gov/Phil

picasso.ucsf.edu/~ulyanov/Structures/prion.html

INVESTIGATING AN OUTBREAKCenter for Disease Control (CDC)

1) Prepare for field work2) Establish the existence of an outbreak3) Verify the diagnosis4) Define and identify the cases5) Describe and orient the data in terms of time, place,

and person6) Develop hypotheses7) Evaluate hypotheses8) Refine hypotheses and carry out additional studies9) Implement control and prevention measures10) Communicate findings

• Is the incidence of the disease greater than what is normal for the area and time?

Places Gone Foods Eaten Activities

INITIALS: CASE #:_______ SEX: ILL? (YES/NO)

SGOT AltSGOT Diagnostic Lab

Signs and Symptoms

Case# InitialsDate of Report

Date of Onset

Physician Diagnosis

N V A F DU J HAIgM Other Age Sex

1 JG 10/12 10/6 Hep A + + + + + + + 37 M

2 BC 10/12 10/5 Hep A + - + + + + + 62 F

3 HP 10/13 10/4 Hep A + - + + +S*

+ 30 F

4 MC 10/15 10/4 Hep A - - + + ? - +Hbs/ Ag-

17 F

5 NG 10/15 10/9 NA - - + - + + NA NA 32 F

6 RD 10/15 10/8 Hep A + + + + + + + 38 M

7 KR 10/16 10/13 Hep A + - + + + + +SGOT = 240

43 M

S*=Sclera;, N=Nausea; V=Vomiting; A=Anorexia; F=Fever; DU=Dark urine; J=Jaundice; HAIgm=Hepatitis AIgM antibody test

LEGIONELLOSIS

• What Is It? A type of pneumonia caused by the bacterium Legionella pneumophila.

• Source: Contaminated water sources, such as showers, fountains, cooling systems, humidifiers, hot tubs and spas

• Cause of Spread: Spray from contaminated sources

• Normal Incidence: For Virginia, a 5-year average of 20 cases per year (about 2/month).

• Historical Relevance: 1996 outbreak in the Lynchburg, VA, region. 23 confirmed cases with 2 deaths.

phil.cdc.gov/Phil



and person6) Develop hypothesis7) Evaluate hypothesis8) Refine hypothesis and carry out additional studies9) Implement control and prevention measures10) Communicate findings

CALCULATE AN ODDS RATIO

Case Patients

Controls Total

Ate at Restaurant A?

Yes a = 30 b = 36 66

No c = 10 d = 70 80

Total: 40 106 146

(a)(d)/(b)(c) = 5.8

Location

Visited the

Location?Cases (ill)

Controls (not ill)

Odds Ratio

HOMECOYes a = 9 b = 2

No c = 1 d = 8

COFFEE JUNCTION

Yes a = 5 b = 3

No c = 5 d = 7

VALUE WORLD Yes a = 5 b = 6

No c = 5 d = 4

Number of people whoate specified item

Number of people who did not eat specified item

Food Ill Well TotalAttack

Rate %

Ill Well TotalAttack

Rate %

Baked Ham

29 17 46 63 17 12 29 59

Spinach 26 17 43 60 20 12 32 62

Mashed potatoes*

23 14 37 62 23 14 37 62

Cabbage salad

18 10 28 64 28 19 47 60

Jell-O 16 7 23 70 30 22 52 58

Rolls 21 16 37 57 25 13 38 66

Brown bread

18 9 27 67 28 20 48 58

Milk 2 2 4 50 44 27 71 62

Coffee 19 12 31 61 27 17 44 61

Water 13 11 24 54 33 18 51 65

Cakes 27 13 40 67 19 16 35 54

Ice Cream (van)

43 11 54 80 3 18 21 14

Ice Cream (choc )*

25 22 47 53 20 7 27 74

Fruit Salad 4 2 6 67 42 27 69 61

Attack Rates by Items Served at a Church Supper,Oswego, New York, April 1940



and person6) Develop hypothesis7) Evaluate hypothesis8) Refine hypothesis9) Implement control measures10) Communicate findings

OUTBREAK AT MIDDLIN HIGH

• Students are getting sick …. Why?

• 15 sick, so far

• Began getting sick Sunday.

• It’s now Wednesday… is the epidemic over?

Activity Summary Data Table

ACTIVITY # ILL STUDENTS INVOLVED IN

ACTIVITY

# ILL STUDENTS NOT INVOLVED

# WELL STUDENTS INVOLVED IN

ACTIVITY

# WELL STUDENTS NOT INVOLVED

Football 8 7 6 4

Café 12 3 8 2

Fair 9 4 5 5

Swimming 8 7 6 4

Cookout 13 2 4 6

FoodNumber of Students Who Ate the Item Number of Students Who Did Not Eat the

Item

Ill Well Total Attack Rate % Ill Well Total Attack Rate %

Chicken 5 3 8 10 7 17

Hamburger 6 3 9 9 7 16

HomemadeIce Cream

13 0 13 2 10 12

Celery 7 3 10 8 7 15

Milk 7 3 10 8 7 15

Hotdog 5 2 7 10 8 18

YOU ARE A CDC INVESTIGATOR

• Your group is a CDC team

• Your assignment is to investigate the illness, determine its source, and recommend action

• You must follow the proper CDC steps as previously discussed

TREATMENTS

• Antibiotics– Only for bacteria– Resistance becoming a problem

• Innoculations

OUTBREAK! Portrait of an Epidemic .

Documents

Transcript of OUTBREAK! Portrait of an Epidemic .