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