Management of a Cryptosporidiosis Outbreak in the South East – Lessons Learned

1

Management of a Cryptosporidiosis Outbreak in the South East –

Lessons Learned

Dr BethAnn Roch

Dr Ann Marie O’Byrne

Consultants in Public Health Medicine, HSE-SE

On behalf of the Incident Response Team

2

Outline of Presentation

• Description of outbreak

• Results

• Action taken

• Discussion – Issues arising– Lessons learned

3

4

Problem Identification

• Trigger: 4 cases of cryptosporidiosis in a 3 week period in Carlow

• Notifiable disease in ROI since Jan 2004

Immediate actions• Enhanced surveillance• Contact PEHO County Council• Contact GPs advise vulnerable i.c. to boil water

AIG to send stool samples• Meeting convened between HSE-SE and County

Council

5

Epidemic Curve

Epi Curve for all cases

543

Cases 21

24-Jan

31-Jan

7-Feb

14-Feb

21-Feb

28-Feb

7-Mar

14-Mar

21-Mar

28-Mar

4-Apr

11-Apr

18-Apr

25-Apr

2-May

9-May

Onset (Week Commencing)

6

Descriptive Epidemiology• 31 laboratory confirmed cryptosporidiosis

• 18 females, 13 males: 8 cases hospitalised

Age Distribution of Cases

8

3 2

14

3

10

5

10

15

20

25

0-5 6-20 21-40 41+Age Groups

Nu

mb

er o

f C

ases

Female

Male

7

Geographical Distribution of

Cases

8

• Other risk factors– crèche contacts (8)– swimming pool (5)– private wells (9)– animals (14)– travel (3)

• 11 had no RF other than town water

Enhanced Surveillance

9

• Water results– Cryptosporidium 0.04/10L

– Giardia 0.02/10L

– Microbiology clear

• Faecal results– 31 laboratory confirmed cases

– 7 samples sent for genotyping: C. hominis

Results

10

• Regular meetings of IRT

• Swimming pool sampling and advice• Private wells sampled• Crèche visits and advice

• Council water measures – Water sampling– Risk assessments– Boil notice– Programme of works to minimise risk

Actions

11

Notification of cases, onset of illness and actions taken

0

5

10

15

20

25

30

35

40

17-J

an

24-J

an

31-J

an

7-F

eb

14-F

eb

21-F

eb

28-F

eb

7-M

ar

14-M

ar

21-M

ar

28-M

ar

4-A

pr

11-A

pr

18-A

pr

25-A

pr

2-M

ay

9-M

ay

16-M

ay

23-M

ay

30-M

ay

6-Ju

n

Week Commencing

Nu

mb

er o

f ca

ses

by

onse

t of

illn

ess

0

5

10

15

20

25

30

35

40

Cu

mu

lati

ve n

otif

icat

ion

of

case

s

Date of Onset Date of Notification

Boil water advice period 14/04/05 - 24/05/05

Sion Cross output reduced22/3/05 - 26/03/05

12

Issues arising

• Water

• Advice to vulnerable populations

• Communication

13

Cryptosporidium species

• Faecal– C. hominis

• Water– C. parvum– C. andersoni– C. muris

• Implications – reassurance?– Intermittent excretion, small dose infective dose– Immunocompromised– Evidence of breakthrough

14

An ‘acceptable’ level• Sampling

– Volume 500-1000L– Grab/continuous– 2 filters/3 labs

• Standards– UK– NI and Scotland

• Types identified– Virulence of C hominis

• Nature of source• Decision – 0.05 oocysts/10L

15

0.0

0.1

0.2

0.3

0.4

0.52-

Mar

12-M

ar

22-M

ar

1-A

pr

11-A

pr

21-A

pr

1-M

ay

11-M

ay

21-M

ay

31-M

ay

10-J

un

20-J

un

Date

No.

of

occy

sts

per

10

LBoil water advice period

14/04/05 - 24/05/05

Cryptosporidium

16 Source: Carlow County Council

0

2

4

6

8

10

12

14

16

18

20

20-Sep-04 9-Nov-04 29-Dec-04 17-Feb-05 8-Apr-05 28-May-05 17-J ul-05

Clostridium Perfringens No./100ml

Clostridium perfringens

17

C. perfringens and Cryptosporidium

0

2

4

6

8

10

12

14

16

18

20

Date

Clo

stri

diu

m p

erfr

ing

ens

/100

ml

0

0.05

0.1

0.15

0.2

0.25

0.3

Oo

cyst

s/10

L

Clostridium/100ml

No. of oocysts /10L

18

0.00.10.20.30.40.50.60.70.80.91.01.1

Tur

bidi

ty (N

TU

)

In line turbidity of filter outletGrab sample of final water turbidity

Standard 1 NTU

Turbidity

Source: Carlow County Council

19

0

5

10

15

20

25

30

3531

-Dec

3-Ja

n

10-J

an

17-J

an

24-J

an

31-J

an

7-F

eb

14-F

eb

21-F

eb

28-F

eb

7-M

ar

14-M

ar

21-M

ar

28-M

ar

4-A

pr

11-A

pr

18-A

pr

25-A

pr

02-M

ay

Week commencing

Nu

mb

er o

f ca

ses

by

onse

t

0

5

10

15

20

25

30

35

Rai

nfa

ll (m

m)

Date of Onset

Rainfall

Rainfall levels & onset of illness

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Advice to vulnerable populations

• Infants– Widespread availability/use of bottled water

– FSAI recommendations

• Immunocompromised– Advised through medical professionals

– Recommendations• UK and USA

• Proposed Irish guidelines

• Recommendations of IRT

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Communication

• Proactive– Council meetings

– Press interviews

– Notice distribution and updates

– Helpline

– Website

– FAQs

– Links

• Website www.carlow.ie

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Communication - interagency

• Health Service and County Council– IRT – engineers, EHOs, public health doctors,

surveillance scientists, microbiologist– Protocol for microbiological incidents– Water Liaison group meetings

• Reports written in collaboration• Presentations supported • Regular meetings• Update protocol

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Lessons learned

• Interpretation of water results

• Advice to vulnerable groups

• Importance of communication

• Building good working relationships

• Management of water incidents is complex and requires input from several different disciplines.

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Acknowledgements

• HSE-SE staff & Carlow County Council

• Dr Phil Jennings, A/DPH, HSE-M

• Dr Derval Igoe/Dr Paul McKeown, HPSC

• Dr Maire O’Connor, Consultant in PHM, HSE-E

• Dr Gordon Nichols, Deputy Head, Environmental & Enteric Diseases Dept, HPA

• Dr David Stewart, DPH, EHSSB

• Ms Gemma Leane, HSE-SE