Emerging Infectious Diseases: SARS and Avian Influenza: Emerging Infectious Diseases: SARS and Avian Influenza Sonja J. Olsen, PhD International Emerging Infections Program Thailand Ministry of Public Health - US CDC Collaboration


Recent Outbreaks in SE Asia: Recent Outbreaks in SE Asia 1997 Influenza A (H5N1) in Hong Kong Spread from chickens to humans, 6 deaths 1999 Large outbreak of encephalitis in Malaysia Spread from pigs to humans Newly emergent paramyxovirus, Nipah virus


International Emerging Infections Program: International Emerging Infections Program http://www.cdc.gov/ncidod/global/ieip/index.htm


Recent Outbreaks in SE Asia: Recent Outbreaks in SE Asia 2002-3 Outbreak of Severe Acute Respiratory Syndrome Likely spread from animals to humans 2003-4 Avian influenza A (H5N1) Spread from chickens to humans Human cases in Viet Nam and Thailand


Slide5: Bangkok Post


Slide6: http://www.who.int/csr/sars/epicurve/epiindex/en/index1.html


Slide7: SARS Caused by a Coronavirus http://www.who.int/csr/sars/coronavirus/en/


Origin of SARS: Origin of SARS Animal origin Masked palm civet Raccoon dog Chinese ferret badger Studies in China Animals Humans who work with animals


Epidemiologic Characteristics: Epidemiologic Characteristics Incubation period 4 days (range, 2-10) Transmission through direct contact or droplet spread Most transmission to close contacts 21% of cases in health care workers Infectious period peaks on days 5-15 Mortality 15% overall 0%(0-24), 6%(25-44), 15%(45-64), 52%(>64)


SARS Highly Infectious : SARS Highly Infectious


Chain of Transmission at Hotel M: MMWR March 28, 2003 Chain of Transmission at Hotel M


Apartment Complex: Apartment Complex 321 cases identified 66% reported having diarrhea 4% reported contact with SARS patient 8% reported recent travel to mainland China Transmission Sewage system – small droplet, airborne Person-to-person Shared communal facilities


Airline Transmission of SARS: A B C D E F No illness (person interviewed) Probable case “Index” Case 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 Empty seat Crew No illness (person not interviewed) Airline Transmission of SARS 22 infections 5 deaths Olsen et al. New Engl JMed 2003;349:2416


Measures to Reduce Airline Transmission of SARS: Measures to Reduce Airline Transmission of SARS Aircraft Decontamination Fever Screening Voluntary Use of Masks Bangkok Post


Good Infection Control: Full airborne precautions Double gloves Double Gown Tight-fitting mask (N100) (N95) Cap and Goggles Shoe covers Good Infection Control


Repercussions of SARS: Repercussions of SARS Large economic impact Strain on health care High profile


Avian Influenza: Avian Influenza Discovered in Italy over 100 years ago Can occur in most species of birds Outbreaks have occurred throughout the world Viruses vary widely in pathogenicity


Slide18: © European Communities, 1995-2004


Avian Influenza A (H5N1) in Asia: © European Communities, 1995-2003 April 7, 2004 Avian Influenza A (H5N1) in Asia


Current H5N1 Outbreak: Current H5N1 Outbreak H5 avian disease is widespread across Asia A least 9 affected countries in 2004 >100 million birds culled or died Human infections limited to Viet Nam and Thailand 40 cases 73% mortality Concerns about a pandemic if H5 reassorts with H1 or H3


Three Possible Control Points to Prevent Reassortment: H1 or H3 Three Possible Control Points to Prevent Reassortment X H5 1 2 3


Prevent Human Infection Through Vaccination: Prevent Human Infection Through Vaccination Key factors Burden of influenza is substantial 42,371 cases reported in passive surveillance system (2003) True burden 92-fold greater Seasonal coincidence of avian and human influenza Vaccine not currently recommended 1


Human Influenza Burden is Substantial in Thailand: Human Influenza Burden is Substantial in Thailand *Annualized **Prospective population-based virologic surveillance for influenza in patients with influenza-like illness


Control avian H5 disease: Control avian H5 disease Key factors Bird surveillance shows avian disease is widespread in Thailand Culling has not eradicated the disease Substantial economic costs due to infection and culling Poultry vaccine currently banned in Thailand 2


January - May 2004: 61 affected provinces Poultry culled in 5km radius around H5 infected poultry 30 million dead or culled January - May 2004 http://www.dld.go.th/home/bird_flu/birdflu.html


July - September 2004: 34 affected provinces Culled only infected poultry 1 million dead or culled July - September 2004 http://www.dld.go.th/home/bird_flu/birdflu.html


Broadened Species Range in 2004: Broadened Species Range in 2004 Poultry Chicken Ducks Geese Turkeys Ostriches Quails Peacocks Pigeons Crows Other animals Domestic cats White tiger Clouded leopard Humans


Reduce human-avian interaction through public education: Reduce human-avian interaction through public education Key factors Poultry exposure is extremely common Most cases are in children Public is knowledgeable about bird flu yet some risk remains Difficult to change behavior 3


Poultry Exposure is CommonSa Kaeo, Thailand: Poultry Exposure is Common Sa Kaeo, Thailand 1.3% of poultry is on commercial farms 178 farms 31,221 poultry 98.7% of poultry is in backyards 73% of households have backyard birds 2,410,820 poultry 178 farms 81,695 households with backyard birds


Recent Development: Recent Development Family cluster 3 family members, 1 lived in another province H5N1 confirmed infection Person-to-person transmission No further spread No significant mutation to virus


Summary: SARS and Avian influenza : 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


Expect the Unexpected: Expect the Unexpected Monkeypox West Nile virus Nipah virus Avian influenza SARS