Severe Acute Respiratory Syndrome (SARS)

Somsak Lolekha MD, PhD

SARS• Mid November-February, >300 people in China’s

Guangdong province had the same disease with 5 deaths.• February 26, 2003, a business man (index case) was

admitted to hospital in Hanoi. He was referred to Hong Kong and died on March 13, 2003

• March 5, seven health care workers who had cared for the index case also became ill in Hanoi.

• March 12, 20 health care workers developed influenza like symptoms in Hong Kong.

• March 11, a health care traveled to Thailand from Hanoi had been unwell and was sent to hospital for isolation. He died on March 29,2003. No evidence of transmission of SARS in Thailand.

Index case in Hong Kong outbreak

• A visitor from Mainland China was sick a week before staying at the Metropole hotel in Kowloon. 7 people who contracted SARS recently stayed or visited the ninth floor of the hotel between 12 February and March 2.

• The 7 persons investigated include 3 visitors from Singapore, 2 from Canada, one China mainland visitor and a local Hong Kong resident.

• The local Hong Kong resident is believed to be the index case had visit an acquaintance staying at the hotel from 15-23 February,2003.

• He was an index case in the outbreak in the Prince of Wales Hospital in Hong Kong

Summary of reported cases of SARS28 Mar 2003

Country Total No. No. of deaths Local transmission

of cases

German 4 0 NoneCanada 37 3 YesChina, Guangdong 806 34 YesSingapore 89 2 YesHong Kong 470 10 YesTaiwan 10 0 YesThailand 3 1 NoneUnited Kingdom 3 0 NoneUnited States 59 0Viet Nam 58 4 YesOther 11 0 Yes

Total 1550 54

Reported Cases of SARS

0

200

400

600

800

1000

1200

1400

1600

1800

17 18 19 20 21 22 23 24 25 26 27 28 29

World

HongKong

Death

Reported Cases of SARS in Hong Kong

0

50

100

150

200

250

300

350

400

450

500

17 18 19 20 21 22 23 24 25 26 27 28 29

Countries with SARS

• Affected countries: country with the evidence of transmission of the disease e.g. Hong Kong, Hanoi, Guangdong province in China, Singapore, Taiwan

• Countries with few imported cases but do not transmit any further.

MMWR 2003;52:241-55

Guideline for presumptive diagnosis of SARS

• Onset of illness after February 1, 2003• Fever (>38 C) and• One or more signs and symptoms of respiratory

illness including cough, shortness of breath, difficulty breathing, hypoxia, radiographic finding of pneumonia, or respiratory distress and

• History of travel to Hong Kong, Mainland China, Hanoi or Singapore within 10 days of symptom onset or

• Close contact with persons with SARS within 10 days of onset of symptoms

March 30, 2003

SARS• Incubation period: 3-5 days (range 2-10 days)

• Etiology: likely to be virus in family Coronaviridae

• CBC: normal, leucopenia(by day 3-4), thrombocytopenia (less common)

• Signs and symptoms: fever, headache, malaise, coughing, shortness of breath

• Transmission: man to man, close contact, secondary attack rate >50%

• Fatality: 54 out of 1550 (3.5%)

• Over 90% of the early cases occur in healthcare workers

• Most of the patients involve family members and other close contacts of infected people and health care workers.

Family Paramyxoviridae

Sub-family ParamyxovirinaeGenus Morbillivirus

Measles virusGenus Paramyxovirus

Parainfluenza virus Genus Rubulavirus

Mumps virusSub-family Pneumovirinae

Genus PneumovirusRespiratory Syncytial virus

Genus Metapneumovirus

RNA-containing virus with helical symmetry and enveloped

sensitive to ether, acid, and heat. Co-infected.

Family Coronaviridae

Structure: non-segmented, linear, single strand RNA+ helical, envelopedDiseases: Common cold, pneumomia, gastroenteritisVirulent factors: E2 glycoproteinMode of transmission: inhalation of aerosols; respiratory transmission from person-to-person, indirect through fomites hand contamination, particle aerosols .Incubation period: 2-5 days (2-10 days)Communicability: during acute and convalescent stagesDrug susceptibility: no specific antiviralsSusceptibility to disinfectants: 1% sodium hypochlorite, 2% glutaraldehydePhysical inactivation: sensitive to heatSurvival outside host: up to 3 hours on environmental surface

Coronavirus

Corona virus

Clinical Features of SARS

Symptoms Per cents

Fever 100Malaise 100Chills 97Headache 84Myalgia 81Dizziness 61Rigors 55Cough 39Sore throat 23Runny nose 23

Clinical course of SARS

• Incubation period: 3-7 days• The illness generally begins with a prodrome of fever >38o C,

chill, malaise, headache, myalgias. Normal CBC• After 3-7 days, a lower respiratory phase begins with the onset of

a dry, non-productive cough or dyspnea that may be accompanied by or progress to hypoxia.

• There are 2 groups of patients– Group one: the majority (80%-90%), characteristic symptoms

will progress to about day 6 or 7 and then will spontaneously start getting slowly better.

– Group two: 10%-20% has a more severe form of the disease and progress to acute respiratory distress syndrome, many of them will require mechanical ventilatory support.

Clinical Course of SARS

Infected by Corona virus

Incubation period 2-10 days

Fever >38 C, malaise, headache, chill

Respiratory symptoms, nonproductive coughDifficulty breathing,

3-7 days

Recover slowly after 7 daysProgressively worse on 10-14 days and died on17-18 days90%

Radiological finding in SARS

• Chest X-ray (CXR) may be normal during the first few days of illness

• Patchy CXR changes are sometimes noted in the absence of chest symptoms

• CXR findings typically begin with a small unilateral patchy shadowing, and progress over 1-2 days to become bilateral and generalized, with interstitial/confluent infiltrates.

• Adult Respiratory Distress Syndrome (ARDS) has been observed in a number of patients in the end stages.

Management of suspect case of SARS

• Send the patient to designated examination room or ward• Issue patients with special mask• Obtain and record detailed clinical, travel and contact

history during the last 10 days• Chest X-ray (CXR) and CBC• If CXR is normal• Provide advice on personal hygiene, avoidance of

crowded areas and public transportation, remain at home until well

• If CXR demonstrate uni- or bilateral infiltration hospitalize under isolation

Management of probable case of SARS

• Hospitalize under isolation or cohorted with other SARS cases

• Sample for laboratory investigation and exclusion of known causes of atypical pneumonia– Throat and nasopharyngeal swabs and cold agglutinin– Blood culture and serology– Urine– Broncho alveolar lavage

• CBC alternate days• CXR as clinically indicated• Treat as clinically indicated

Screening questions for SARS

• We should ask the patients or passengers 2 questions.

• First question relates to symptoms, asking about fever, cough or difficult in breathing.

• Second question asks about possible exposure, whether you know you have been in contact with a case of SARS, whether you have worked or visited or been a patient in a hospital where there is SARS, or whether you have member of your family has been a suspect or probable case of SARS.

Advice for Airline and Traveler

• Alert the destination airport of any passengers meeting the case definition criteria

• Arriving passengers who are symptomatic should be referred to health authorities for assessment and care

• Aircraft passengers and crew should be informed of the person’s status as a suspect case of SARS

• The passengers and crew should provide all contact information for how passengers can be reached for the subsequent 14 days to airport health authorities.

• Persons planning elective or nonessential travel to Hong Kong, Guangdong province, Singapore, Hanoi may wish to postpone their trips.

Hospital Infection Control Guidance

• Airborne precautions– Negative pressure rooms with the door closed– Single rooms with their own bathroom facilities– Cohort placement in an area with an

independent air supply and exhaust system– Turning off air conditioning and open windows

for good ventilation is recommended if an independent air supply is unfeasible

Hospital Infection Control Guidance

• Contact precautions

– Use gown and gloves for contact with the patient or their environment

• All visitors, staff and students should wear a N95 mask (or surgical mask) on entering the room

• Patient movement should be avoided as much as possible. Patients being moved should wear a surgical mask to minimize dispersal of droplets.

Management of Exposures to SARS for Healthcare and other Institution Settings

• Exclusion from duty, if fever or respiratory symptoms develop during the 10 days following an unprotected exposure to SARS until 10 days after the resolution of fever.

• Surveillance (active and passive)

• Close contacts of SARS with either fever or respiratory symptoms should not be allowed to enter the healthcare facility as visitors.

• Educate all visitors