CUHKSPH/PCAA Inauguration1st Scientific Symposium

Emerging infectious diseases in the past and present decade

Dr Thomas TsangCentre for Health Protection, Department of Health

Feb 22, 2011

Past decade: Observations

1. Pandemics triggered by pathogens with animal link

• SARS Co-V– ? Bats– ?Palm civets as interm

ediate host

• Pandemic H1N1 (2009)– Reassortment with swi

ne flu virus

2. Pandemics travel much faster than anticipated

• Containment difficult despite theoretical possibility

• Present surveillance methods lag behind epidemic progression

• Sharing of epidemic intelligence vital

• Contingency planning must start well before pandemic

3. Epidemics can be halted by public health measures

• SARS– Quarantine & isolation– Hygiene and social

distancing

• Dengue fever– Anti-mosquito

measures

4. Strengthening of infrastructures vital

• Updated legislation

• Capacity building– e.g., surveillance systems, field epidemiology, infection control,

contingency planning

• New programs– vaccination schemes

• Closer public health / clinical interface

• Scientific Committees to pool expertise

• Open channels with Mainland and regional countries

5. Risk communication is all important

New decade: Trends & predictions

1. Another respiratory pandemic??

• Pandemic flu unpredictable– H2? H5? H9? Swine?

• Zoonotic pathogens– Is stopping at source feasible?

• Laboratory leaks

• Bioterrorism– Flu, smallpox, etc.

1997 2003 2009 2015

Avian influenzaH5N1

SARS Human swine influenza

?

2. Multi-drug resistance of increasing concern

• Global trend

• CA-MRSA, C. difficile, Acinectobacter, NDM-1 and other carbapemenase resistant bacteria, etc.

• World Health Day, April 2011

• New antibiotics lag behind due to R&D resource input

Emergence of New Delhi metallo-β-lactamase (NDM-1) producing Enteroba

cteriaceae

Lancet Infect Dis. 2010 Sep;10(9):597-602

Increasing reports of Clostridium difficile infection in UK

Source: Voluntary surveillance of Clostridium difficile in England, Wales and NorthernIreland, 2009. HPA

Source: ECDC, EMEA. The bacterial challenge: time to react. 2009 Sep

3. Climate change may alter pattern of infectious diseases

World Health Organization 2009

4. Some epidemics may flare up from time to time

• Influenza

• EV71 & other enteroviruses

• Norovirus

• HIV

• HEV

• Dengue fever

• Others ???

EV71 periodicity

Number of EV71 infection, 2001 – 2011 (as of Feb 17)

30

5 1

35

8 16 12

98

31

101

50

20

40

60

80

100

120

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Year

Nu

mb

er o

f ca

ses

Voluntary report Statutory report

Source: Department of Health, Hong Kong

HIV epidemic among MSM in Hong Kong (2000-2010)

Source: HIV reporting system, Department of Health, Hong Kong

5. New vaccines ??

• Vaccines under development– Dengue fever, Malaria, HIV, etc.

• Use of existing vaccines– PCV, rotavirus, HPV, etc.

6. Regional accomplishments

• Measles eradication

• Hepatitis B elimination

• Polio-free status

7. Social networks and search engines find increasing use in

disease surveillance

• Powerful GIS systems• How disease spread

through ‘networks’• Rumor filters

Thank you