SARS and Avian Influenza: Public Health Priorities

SARS and Avian Influenza:Public Health Priorities

Scott F. Dowell, MD, MPHInternational Emerging Infections Program

Thailand Ministry of Public Health - US CDC Collaboration

Chest Xray, Day 2

Dr. Carlo Urbani

Guangdong Province,

China

A

A

Hotel MHong Kong

B

J

H

Hospital 2Hong Kong

A

H

J

B

4 other Hong Kong Hospitals

CD

E

Hospital 3 Hong Kong

Hospital 1 HK

Hospital 4 Hong Kong

2 family members

C D E

34 HCWs

HCW

B Germany

Bangkok

Singapore

United States

I

IL§

M§

Vietnam

K † IrelandK †

37 HCWs

HCW

0 HCWs

28 HCWs

156 close contacts of HCWs and

patients

FG †

Canada

G †

F

4 family members

10 HCWs

37 close contacts

99 HCWs (includes 17 medical students)

4 HCWs*

3 HCWs

HCW

HCW

2 family members

Unknown number

close contacts

2 close contacts

 * Health-care workers; † All guests except G and K stayed on the 9th floor of the hotel. Guest G stayed on the 14th floor, and Guest K stayed on the 11th floor; § Guests L and M (spouses) were not at Hotel M during the same time as index Guest A but were at the hotel during the same times as Guests G, H, and I, who were ill during this period.

Chain of transmission among guests at Hotel M—Hong Kong, 2003

Data as of 3/28/03

A B

CD

E F

No illness (person interviewed)

Probable case

“Index” Case

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Empty seat

CrewNo illness (person not interviewed)

Airline Transmission of SARS

Olsen et al. NEJM 2003;349:2414

Measures to Reduce Airline Transmission of SARS

Aircraft Decontamination

Fever Screening

Voluntary Use of Masks

Chest Xray, Day 13

Clues to the Causative Agent

• Epidemiology – highly transmissible respiratory pathogen

• Clinical – unusually severe disease

• Laboratory – generally consistent with virus

• Pathology – possibly paramyxovirus

• No known agent could explain all features

Coronavirus – EM appearance

Personal Protective Equipment

• N-95 or better respirator

• Head cover

• Goggles or face shield– eyeglasses not adequate

• Double gown

• Double gloves

• Double shoe covers

SARS on Hospital SurfacesSurface, Hospital B, Taiwan # Positive/# Tested

Patient rooms (71%)Endotracheal tube 3/3Bedrail 3/4Ventilator panel 1/3Other 3/4

Nursing stations (56%)Telephone 1/3Computer mouse 2/2Doorknob 1/2Other 1/2

Public areas of hospital (20%)Elevator handrail 1/1Other 0/4Total 16/28 (57%)

Dowell et al. CID 2004;39:652

Intubation of a SARS Patient

Influenza – “Drift”Influenza

0

5

10

15

20

25

30

Jan

-94

Jul-

94

Jan

-95

Jul-

95

Jan

-96

Jul-

96

Jan

-97

Jul-

97

Jan

-98

Jul-

98

Jan

-99

Jul-

99

Jan

-00

Jul-

00

Month/Year

% P

ositi

ve

Feb

Feb

Jan Dec

Dec

Dec

Influenza – “Shift”

US Infectious Disease Mortality:The Impact of Influenza and AIDS

Armstrong. JAMA 1999;281:61

Avian Influenza in Thailand?

Avian Influenza in Asia(10 February, 2004)

Intensive Pneumonia Surveillance

• Active• Population-based• CXR-confirmed• Laboratory testing

– Influenza

– Other viruses

– Bacterial agents

• Community surveys

Nakorn Phanom

Sa Kaeo

Locations of Registered Poultry Farms Sa Kaeo, Thailand

Poultry Exposure is Common

• There are ~6 birds to every person in Sa Kaeo Province

• 1.3% of poultry is on commercial farms– 178 farms– 31,221 poultry

• 98.7% of poultry is in backyards– 2,410,820 poultry

A Cluster of H5 Cases

• Three family members linked coincidentally during investigation of another pneumonia case

• Urgent concern about person-to-person transmission

• At the time cluster was recognized; Index case dead, cremated Mother dead, body embalmed Aunt admitted to hospital

• Interviews rapidly conducted on family, contacts, neighbors, and healthcare workers

Investigation at Home of Index Patient

Timeline Timeline of of

Exposures Exposures and Illnessand Illness

Laboratory Investigation

• Immediate and urgent effort to collect specimens• Specimens promptly shared with WHO network• Index patient dead, cremated

0.5ml serum from day 6 of illness Mother’s body embalmed

Lung and other tissues tested by PCR

• Aunt survivedNP and OP swabs tested by cell culture, RTPCRAcute and convalescent serum (neutralization, ELISA)

Mother: Lung Tissue Pathology

Photo courtesy of S. Zaki

0.1

Mdk/Vietnam/4/2004Mdk/Vietnam/17/2004

Chicken/Laos/44/2004Thailand/Kan/353/2004Thailand/2SP33/2004

Vietnam/3218/2004Thailand/1KAN1/2004Thailand/PCBR/6231/2004Vietnam/HN30262/2004

Thailand/PCB2031/2004ipGoose/Cambodia/25/2004

Vietnam/1203/2004Vietnam/1194/2004

Thailand/Pranom5147/2004Thailand/Pranee5223/2004

Thailand/SP83/2004Mdk/Vietnam/MDGL/2004

Chicken/Laos/7192/2004Chicken/Vietnam/ncvd31/2004

Vietnam/3212/2004Chicken/Vietnam/CM/2004

Vietnam/HN30259/2004Thailand/16/2004

Thailand/Chai622/2004serplChicken/Indonesia/11/2003

Chicken/Korea/ES/2003Duck/China/e3192/2003

hvriDuck/Harbin/15/2004Hong Kong/213/2002

Duck/Hong Kong/739/2002RBPochard/Hong Kong/821/2002

Teal/Hong Kong/2978/2002Chicken/Hong Kong/3175/2001

Hong Kong/156/1997Goose/Guangdong/96

HA Gene HA Gene Sequence:Sequence:•Genotype ZGenotype Z

•Resistant to amandatineResistant to amandatine

Conclusions from Family Cluster

• Probable person-to-person transmission• No further spread to contacts• No significant mutation of virus

– All gene segments were of avian origin– Critical binding and cleavage sites unchanged

• Isolation precautions needed for H5 patient care• Future clusters also warrant intensive investigation

Summary: SARS and Avian influenza

• SARS redefined emerging zoonoses – Broad economic and public health impact

• Avian flu: unprecedented & unpredictable– Scale of the epizootic unprecedented– Ongoing potential for re-assortment event