Avianflu Sars 05
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Transcript of Avianflu Sars 05
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Emergingand Reemerging
DiseasesSevere Acute Respiratory Syndrome
(SARS)
Teresita S. de GuzmanDepartment of Medical Microbiology
College of Public Health
University of the Philippines, Manila
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Factors for Emergence
Microbial adaptation
Human susceptibility Climate and weather Changing ecosystems Land use and economic development Human behavior and demographics Technology and industry International travel and industry Breakdown of public health Poverty and social inequality War and famine Lack of political will
Intent to harm
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SomeEmerging iseases
SARS Avian influenza Nipah virus
Hendra virus Hanta virus E. coli 0157:117
variant vCJD (prion
disease)
West Nile fever
Rift Valley fever N. meningitidis
W135 Ebola
Crimean-CongoHF (hemorrhagic
fever)
WhitewaterArroyo virus
Lyme disease
Lassa Fever virus
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Brief History
SARSwas 1stdescribed during the
2002-2003 global outbreakof severe
pneumonia associated with human deaths
and person to person disease transmission
A large outbreak occurred in late 2002in
Guangdong Province, China
Starting late February 2003, similar illness
was reported concurrently in Vietnam,
Hongkong, Canada, Singapore, Thailand, etc.
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By the time the outbreak was contained
sometime July of 2003, 8,098probable
cases, with 774deaths were identified
in 29 countries ( CDC MMWR, 2003 & URL:
http://www.who.int/csr/sars/country/table2003_09_23/en/)
Initial clinical & laboratory results focused
on several known agents likeChlamydia,influenza virus, metapneumovirus, etc.
A virus isolated from the oropharynx of a SARS
patient subsequently identified as belonging to
Coronavir idaefamily by morphology thru EMstudies, additional culture isolates, immunohisto-
chemistry,immunofluorescence, serologic
assays, RT-PCR, miroarray analysis &
sequencing
http://www.who.int/csr/sars/country/table2003_09_23/en/http://www.who.int/csr/sars/country/table2003_09_23/en/ -
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1stidentified in Vietnam on
Feb. 28, 2003 on a patient with
severe pneumonia with no known
cause by Dr. Urbani, a WHO staff
who consequently died of the
disease in Thailand
super spreading event involving a
cluster of cases in Blk E of the AmoyGardens Housing State in Hongkong
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Rodents & cockroaches as
possible mechanical vectors of
transmission
defective U-traps in bathroom
aerosolization effect of exhaust
fan within small bathrooms cracked sewer pipe
person to person spread
Outbreak was due to unlucky
convergence of environmental
conditions, i.e.:
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The etiologic agent of the syndrome is
now recognized as the
SARSassociated coronavirus
(SARSCoV)
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Virology of SARS-CoV
Family: Coronaviridae
Genus: Corona virus
virions are spherical; 78 nm mean diameter
(+) RNA virus ; 29,727 nucleotide bases
helical nucleocapsid
enveloped with corona (crown)-like spikes
Antigenic groups:
Grp. 1 & 2- mammalian CoVHuman CoV
Grp. 3avian CoV
SARS (4th
lineage)
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Distinct Ultrastructural Features
Of SARS-Associated Coronavirus
Infected Cells
double-membrane vesicles
nucleocapsid inclusions
large granular areas of
cytoplasm
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SARS coronavirusis NOT
a mutant nor a recombination of
existing CoV ; it is NEWand
never seen in humans before
Pathogenesis: infects a variety of mammals & birds
not known number of isolates in humans
neurological symptoms rarely seen incubation period is 6 - 7 days
95% of patients develop symptoms
within 14 da.
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Transmission:
direct mucous membrane (eyes,
nose, & mouth
exposure to virus laden fomites
intense exposureaerosolizing procedures in
hospitals
role of oral-fecal transmissionis unknown
no reported cases yet of vertical
transmission
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Epidemiology:
Risks Factors
health care workers
increase in age (death common
among elderly male sex
presence of co-morbidics
care and slaughter of wildlife for human
consumption environmental contamination and
presence of mechanical vectors
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Virus is stable in feces and urine
At room temp. , 1-2 days
Stable for up to 4 days in diarrheic
stools
isolated in stools on paper, formicaplastered wall after 36 hrs.; glass slides
after 96 hrs.; plastic surfaces & stainless
steel after 72 hrs.loses infectivity after exposure to
disinfectant, etc.; rapidly killed by
560
C heat
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Other Clinical Manifestations
leucopenia; lymphopenia
raised LDHSpecimens to be Collected:
Blood
Respiratory secretions:nasopharyngeal aspirate (NPA)
nasopharyngeal swab (NPS)
oropharyngeal swab (ORS)sputum
Stool (in diarrheic cases)Place in virus transport media (VTM) keep at 40C
BSL-3 facilities & work practices
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Collect specimen during onset
of illness3 days
Maximum shedding of virus at early part
of infection
max. virus excretion from respiratory tract at
about 10 days
virus isolation in stools peaks at 12-14 da.
viral RNA detected in serum; peaks at
6-8 days; undetected by day 12
virus in urine detectable at day 10
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Diagnosis:
Negative staining EM (electronmicroscopy
RT-PCR (very specific but lackssensitivity and standardization)
ELISA
IFAT (immuno-fluorescent Ab test)
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Emergingand Reemerging
DiseasesAVIAN INFLUENZA
(BIRD FLU)
Teresita S. de GuzmanDepartment of Medical Microbiology
College of Public Health
University of the Philippines, Manila
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Information onAVIAN INFLUENZA
Avian influenza A (H5N1) is asubtype of the Type A influenza
virusFrom the family of RNA virusesOrthomyxoviridae
Wild birds are the natural hosts1stisolated from birds (terns) inSouth Africain1961
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The virus circulates amongbirds worldwide
Very contagious among and deadlyin birds, particularlydomesticated birds like chickens
The virus does not typicallyinfect
humansIn 1997, the 1stinstance of directbird-to-human transmission ofH5N1 was documented in an out-
break among poultry in Hong Kong
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Infected birds shed thevirus
in saliva, nasal secretions, andfecesAvian influenza viruses spread
among susceptible birds upon
contact with contaminatedsecretions
Most cases of H5N1infection inhumans are believed to be fromcontact with infected poultryor
contaminated excretions
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Current H5N1 Strain(implicated) In Outbreak
All genes are of bird origin; virus
has not acquired genes fromhuman influenza virus yet
There are likely differentvariations of H5N1 viruscirculating at this time
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Genetic sequencing done onsamples from South Korea&Vietnamshowed that theviruses are slightly different
Genetic sequencing of A(H5N1)virus samples from human cases inVietnam& Thailandshowed drug
resistance to antiviral amantadine& rimantadine (M2 inhibitors)commonly used vs influenza
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Remaining antivirals,oseltamavir& zanamavir
(neuraminidase inhibitors)should be effective still vs.H5N1 strain
Key to containing the outbreakis
the culling(killing) of sick andexposed birdsAll influenza virus can change.
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NO effective vaccine yet vs.
H5N1 avian flu virusAn available vaccine prototype
developed using the 2003 strain ofH5N1 (from Hongkong cases) cannotbe used to expedite vaccine
development; the virus has mutatedsignificantly
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Clinical course (based on the
1997 Hongkong outbreak): fever
sore throat cough severe respiratory distress
secondary to viral pneumonia(seen in several of the fatal cases)Previuosly healthy adults & children, & some
w/ chronic medical conditions were affected
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THANKYOU!!!