Suspect case

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SARS
Severe Acute Respiratory Syndrome
Hatami M.D. MPH 2008 (1387)
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2003(????? ????? ??? 1382) ????? ????? ????
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SARS
Case definition
1 Suspect case 2 Probable case 3 Definitive
case
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1 - Suspect case (1)

• 1. A person presenting after 1 November 2002 (10
  Aban 1381) with history of- high fever (gt38
  C)AND- cough or breathing difficultyAND one
  or more of the following exposures during the 10
  days prior to onset of symptoms- close contact
  with a person who is a suspect or probable case
  of SARS- history of travel, to an affected
  area- residing in an affected area

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Suspect case (2)

• 2. A person with an unexplained acute respiratory
  illness resulting in death after 1 November 2002,
  but on whom no autopsy has been performedAND one
  or more of the following exposures during to 10
  days prior to onset of symptoms- close contact,
  with a person who is a suspect or probable case
  of SARS- history of travel to an affected area
  - residing in an affected area

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2 - Probable case

• A suspect case with
• 1- radiographic evidence of infiltrates
  consistent with pneumonia or respiratory distress
  syndrome (RDS) on chest X-ray (CXR).
• OR
• 2- autopsy findings consistent with the
  pathology of RDS without an identifiable cause.

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Exclusion criteria

• A case should be excluded if an alternative
  diagnosis can fully explain their illness.

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SARS Etiologic Agent

• Order Nidovirales
• Family Coronaviridae
• Torovirus
• Coronavirus
• Grp I
• Grp II
• Grp III

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Seasonal pattern
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Mode of transmission
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Mode of transmission

• Probable major modes of transmission
• Large droplet aerosolization
• Contact
• Direct
• Fomite
• Airborne transmission cannot be ruled out
• ? Role of aerosol-generating procedures
• ? Fecal-oral

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Number of cases by reported source of infection
(Singapore)
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Spread from Hotel M Reported as of March 28, 2003
Guangdong Province, China
A
A
Hotel MHong Kong
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Attenuation

• Attenuation is a phenomenon seen in some members
  of the coronavirus family, where the virulence
  decreases when it jumps from person to person.
• The SARS virus seems to exhibit this phenomenon
  (however, there are no studies yet to prove this).

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Viral pathogenesis - general
local replication
dissemination
Innate cytokines phagocytes NK cells
immune
response
end-organ involvement
Adaptive
primary viremia
secondary viremia
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Incubation Period

• 2-10 days
• Infected people do not pass on the virus to
  others during the incubation period.
• They become infectious only when the first
  symptoms appear cough, sneezing which spread
  droplets containing virus particles.

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Clinical manifestations

• Incubation period 2-10 days
• Onset of fever, chills/rigors, headache,
  myalgias, malaise
• Respiratory symptoms often begin 3-7 days after
  symptom onset

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Clinical manifestations

• Sudden onset of high fever
• Characteristic chest X-rays 3-4 days after onset
  of symptoms
• 10-15 of cases require intensive care and
  mechanical ventilation
• Case fatality about 10
• Intensive and good supportive care

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Symptoms Commonly Reported By Patients with
SARS1-5
Symptom Range () Fever 100 Cough
57-100 Dyspnea 20-100 Chills/Rigor 73-90 Myal
gias 20-83 Headache 20-70 Diarrhea 10-67
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Common Clinical Findings in Patients with SARS
Finding Range ()
Examination Rales/Rhonci Hypoxia 38-90 60-83
Laboratory Leukopenia Lymphopenia Low platelet Increased ALT Increased LDH Increased CPK 17-34 54-89 17-45 23-78 70-94 26-56
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Symptoms Reported by Patients With Diagnostic
SARS-CoV Laboratory Testing, United States, 2003
Symptom Coronavirus Positive (n6) Coronavirus Negative (n28)
Fever 100 96
Cough 100 93
Dyspnea 100 61
Myalgias 83 75
Chills/Rigor 83 68
Headache 67 68
Diarrhea 67 25
Coryza 17 43
Sore Throat 17 43
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Clinical Findings in Patients With Diagnostic
SARS-CoV Laboratory Testing, United States, 2003
Symptom Coronavirus Positive (n6) Coronavirus Negative (n28)
Examination Rales/rhonci 83 23
Hypoxia 83 29
Infiltrates 100 30
Laboratory Leukopenia 17 5
Lymphopenia 83 53
Low platelets 17 5
Increased ALT 60 17
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????????? ??????? SARS
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Diagnostic Approach to Patients with Possible SARS

• Consider other etiologies
• Diagnostic workup
• 1 - Chest radiograph
• 2 - Blood and sputum cultures
• 3 - Testing for other viral pathogens (e.g.
  influenza)
• 4 - Consider urinary antigen testing for
  Legionella spp. and Streptococcus pneumoniae

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Diagnostic Approach to Patients with Possible SARS

• 5 - Save clinical specimens for possible
  additional testing
• Respiratory
• Blood
• Serum
• 6 - Acute and convalescent sera (gt21 days from
  symptom onset) should be collected
• 7 - Contact Local and State Health Departments
  for SARS-CoV testing

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Laboratory Assays for SARS

• Detection of virus
• EM in clinical specimens (CoV-like particles)
• Isolation of virus
• Detection of viral antigens
• Detection of viral RNA (PCR)
• Respiratory secretions
• Stool specimens
• Urine specimens
• Tissue lung and kidney
• Detection of SARS-specific antibody
• IFA
• ELISA
• Neutralization

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Characteristics of SARS-CoV PCR

• Limited experience/data
• Specimens
• 1 - Upper respiratory maybe 50 positivity in
  acute-phase specimens
• 2 - Stool possibly higher sensitivity later in
  illness, e.g., 10-14 days
• 3 - Sputum/BAL probably higher rate of positivity
• 4 - Other specimens, urine, blood, tissues, ?
• Interpretation of Results
• Negative -- does not rule out SARS-CoV infection
• Positive possibility of false positive (test
  error/contamination)

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Diagnosis

• SARS is a clinical and epidemiologic diagnosis
• Laboratory testing can diagnose SARS-CoV
  infection during the acute illness
• Laboratory testing can not rule out infection
  until the convalescent phase of illness

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Radiographic Features of SARS

• Infiltrates present on chest radiographs in gt 80
  of cases
• Infiltrates
• initially focal in 50-75
• interstitial
• Most progress to involve multiple lobes,
  bilateral involvement

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Radiographic Features of SARS
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Treatment of Patients with SARS

• Most effective therapy remains unknown
• Optimize supportive care
• Treat for other potential causes of
  community-acquired pneumonia of unknown etiology

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Treatment of Patients with SARS

• Potential Therapies Requiring Further
  Investigation
• Ribavirin
• ?other antiviral agents
• Immunomodulatory agents
• Corticosteroids
• Interferons
• Others?

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Clinical Features Associated with Severe Disease

• Older Age
• Underlying illness
• ? Lactate dehydrogenase levels
• ? Severe lymphopenia

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Infection Control

• Early recognition and isolation is key
• Heightened suspicion
• Triage procedures
• Transmission may occur during the early
  symptomatic phase
• Potentially before both fever and respiratory
  symptoms develop

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Treatment of Patients with SARS

• Isolation
• Hand hygiene
• Contact Precautions (gloves, gown)
• Eye protection
• Environmental cleaning
• Airborne Precautions (N-95 respirator, negative
  pressure)

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Treatment of Patients with SARS

• Key Objectives
• Early detection
• Containment of infection
• Protection of personnel and the environment of
  care
• Hand hygiene

• Key Strategies
• Administrative measures
• Infection precautions
• Standard
• Contact (droplet)
• Airborne
• Environmental cleaning/disinfection

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SARS Transmission During Aerosol-Generating
Procedures

• Transmission of SARS to healthcare personnel
  during aerosol-generating procedures may be
  particularly efficient
• Clusters detected in Toronto, Hong Kong,
  Singapore and Hanoi
• Intubation, suctioning and nebulization
  specifically implicated

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Why? How?

• Patient infectivity higher?
• Is it Droplet? Contact? Airborne?
• Is it failure to wear protective equipment?
• Is it failure of protective equipment?

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Until Risks During Aerosol-Generating Procedures
Better Defined..

• Limit cough-inducing procedures
• Avoid use of non-invasive positive pressure
  ventilation (e.g., CPAP, BiPAP)
• Protect the environment
• Use closed suctioning devices
• HEPA filtration on exhalation valve port

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Protect Healthcare Personnel DuringAerosol-Generat
ing Procedures

• Limit personnel to those essential for performing
  procedure
• Wear appropriate personal protective equipment
• Gowns and gloves
• Sealed eye protection (i.e., goggles)
• Respiratory protection device

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Respiratory Protection During Aerosol-Generating
Procedures

• Proper fit is essential
• Reassess respirator fit among personnel who may
  be involved in intubation of SARS patients
• Consider better fitting respiratory protection
  devices
• Disposable respirators with better seal, e.g.,
  N99, N100
• Half- or full-face elastomeric (rubber)
• Powered air-purifying respirators (PAPR)

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Management of SARS Exposures in Healthcare
Settings

• Surveillance of healthcare personnel
• Develop list of personnel who have contact with
  SARS patients (I.e., enter room, participate in
  care)
• Encourage reporting of unprotected exposures
• Monitor absenteeism for SARS-like illness
• Management of asymptomatic exposed HCWs

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Management of Asymptomatic Exposed Healthcare
Workers

• No evidence of transmission from asymptomatic
  persons
• Symptomatic HCWs have transmitted
• Active surveillance of HCWs who have unprotected
  exposure is recommended
• Monitor temperature and symptoms before reporting
  to duty
• Ten-day exclusion from duty for HCWs who have
  unprotected exposures during aerosol-generating
  procedures

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Addressing the limited supply of respirators

• Should respirators be reused?
• Disposal after one-time use preferred
• Use up higher level respirators first
• Reuse preferred to no respirator
• Consider using surgical mask to protect
  respirator from contact with respiratory droplets
• Carefully handle contaminated respirator
• Use surgical masks only when respirators are
  unavailable

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Cleaning and Disinfection of the SARS Patient
Environment

• Environment may be a key to transmission
• Clean/disinfect frequently touched surfaces daily
  in in-patient areas
• Bed rails, over-bed table, door knobs, lavatory
  surfaces
• Perform more thorough cleaning at transfer or
  discharge
• Use EPA-registered hospital detergent
  disinfectant
• No need for air fogging or washing of ceilings
  and walls

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Infection Control Principles Applied in the Home

• Early detection of infection
• Containment of infection
• Protection of household members
• Limiting contamination in the home environment

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Key Time Periods

• 10 days after last exposure
• Duration of post-exposure monitoring period
• 72 hour rule
• Period for reassessing early symptoms of SARS
• 10 days after resolution of fever
• Duration of post-SARS confinement

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Guidance for Persons Exposed to SARS

• Asymptomatic exposed persons
• No change in daily activities
• Monitor for respiratory symptoms and fever (i.e.,
  measure temperature twice daily) for 10 days
  after last exposure
• Fever or respiratory symptoms develop
• Notify healthcare provider
• Limit interactions outside the home
• Reassess in 72 hours

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72 Hour Reassessment
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Infection Control for Persons with SARS

• Avoid interactions outside the home (school,
  work, day care, church, shopping)
• Wear surgical mask and avoid public
  transportation if travel outside home is
  necessary
• Limit persons coming into the home

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Infection Control Advice to SARS Patients

• Wear a surgical mask when in the presence of
  other household members
• Contain respiratory secretions in facial tissue
  and place in lined container for disposal with
  household waste
• Perform hand hygiene frequently and especially
  after touching respiratory secretions and other
  body fluids (e.g., urine, stool)

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Advice to Household Members of SARS Patients

• Wear surgical mask when around SARS patient (if
  patient cannot wear mask)
• Perform hand hygiene frequently (hand washing
  with soap and water or use of alcohol-base gel)
• Consider wearing disposable gloves for direct
  contact with body fluids of SARS patients

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Other Infection Control Measures in the Home

• Do not share personal items until thoroughly
  washed with soap and water (towels, linen, eating
  utensils)
• Consider separate sleeping arrangements
• Clean surfaces that are touched frequently or
  come into contact with body fluids (e.g., food
  preparation areas, phones, lavatories)

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SARS Admissions

• If possible, separate wards/areas for each of the
  following categories
• Patients with colds, sniffles and runny noses
  should be isolated in a single room / area
• Suspect cases
• Place in a single room
• Probable cases
• If cohort nursing keep probable and suspect
  cases
• apart
• May share room with other probable cases where
  possible use a single room for all patients

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Components of SARS Isolation

• Facility
• Administrative Controls
• Organization of Isolation Area
• Protective Equipment
• Hand Hygiene
• Patient transport

• Laboratories
• Mortuary Care
• Cleaning and Disinfection
• Waste and Linen Handling
• Patient and family
• education

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Facility

• Isolated from other patient / staff movement
• Good ventilation
• Air movement corridor to room to outdoors
• Sinks and running water
• Adequate bathroom facilities
• Capacity to handle waste and laundry
• Sufficient rooms for expected number of patients
• Contingency plans for converting other areas to
  isolation facilities

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Administrative Controls

• Limit, and control points, of entry to SARS
  ward(s)
• One entrance
• Guard to control entrance
• Log of permitted visitors (Staff visitors)
• Visitors must be restricted or preferably
  forbidden with no exceptions
• Limit patient travel/transport outside unit
• Minimize the number of staff exposure to cases

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Administrative Controls

• Assignment of responsibility
• Determining patient placement
• Overseeing implementation and enforcement of
  infection control measures
• Enforcing access restrictions
• Supply acquisition and distribution
• Surveillance of Health Care Workers

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Clinical Surveillance of Staff

• Maintain list of all staff who worked with SARS
  patients or on the SARS ward
• Systematically monitor for fever
• Twice daily temperature for staff working in the
  area (baseline CXR may be needed )
• Screen for symptoms of SARS-like illness among
  staff reporting for duty
• List contact information for
• Persons visiting or caring for SARS patients
• Contacts of HCWs in close contact with SARS
  patients

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Organization of SARS Isolation Area

• Signs SARS Isolation Area
• Designated area for clean protective equipment
• Instructions for using protective equipment
• Accessible to personnel
• Sufficient inventory to meet daily needs
• Separation of clean and dirty supplies including
  an area for containment of waste and soiled linen
  
• Color-coded bags and containers for contaminated
  waste and laundry

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Protective Equipment

• N-95 Mask must be worn
• Goggles (protective glasses)
• Disposable or Reusable Gowns
• Disposable Gloves
• Head and/or shoe covers
• Shoe covers should be worn when shoes not
  suitable for cleaning

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Key Points

• Wear disposable gowns, gloves and goggles for
  close patient contact
• Wash hands using liquid soap and water when
  leaving the anteroom
• Use an 70 alcohol-based hand rub solution after
  hand washing
• Wash hands when leaving the unit

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Standard Precautions

• Designed to reduce the risk for occupational
  exposure to SARS infection from both recognized
  and unrecognized sources of infection

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Exposures

• Patient
• Blood
• Body fluids including excreta
• Skin lesions

• Health Care Worker
• Blood
• Body fluids including excreta
• Mucous membranes
• Skin lesions