1. What is Atypical Pneumonia?

2. What is SARS?

1. The virus
2. Signs and symptoms
3. High-risk groups
4. Diagnosis
5. Prevention
6. SARS Vaccination development project
7. Treatment
8. Current Situation
9. Case definitions of SARS

1. What is Atypical Pneumonia?

Pneumonia means lung infection. Depending on the type of infective agents, cases diagnosed as “Atypical pneumonia” or as “Unusual pneumonia” can give rise to a wide spectrum of manifestations ranging from mild to serious infections and health consequences.

2. What is SARS?

SARS (Severe Acute Respiratory Syndrome) describes more aptly the nature of the current condition as a severe acute type of “Atypically atypical pneumonia”.

a. The virus

According to WHO (released on 16 April), it is a viral respiratory infection caused by a new coronavirus (SARS-CoV), which is a subgroup of new, genetic mutated coronavirus which may have relationship to certain animal sources.

b. Signs and symptoms

Symptoms usually appear within 2 - 7 days after exposure. Initial symptoms are influenza-like. 94% patients with SARS usually begin with high fever (38oC or above) plus at least one non-specific symptom like chills, malaise, headache, rigors, muscle pain or even diarrhoea. Some may only have mild respiratory symptoms. Symptoms of lower respiratory tract infection may follow a few days later, including non-productive cough and difficulty in breathing. In around 10% of patients, the illness may rapidly progress to respiratory failure requiring intensive medical care. Symptoms can be more variable among elderly patients.

c. High-risk groups

The 4 most important factors related to fatal cases are: old age (especially those aged above 60), co-morbid chronic illness, pneumonia patients who have delayed treatment.

Mode of Transmission and Incubation period

It is transmitted through close person-to-person contact, especially via respiratory droplets produced when an infected person coughs or sneezes. Contact with contaminated surfaces and other body fluids may also be another mode of transmission.

The mean incubation period is estimated to be 6.4 days, however, exceptional cases with up to or more than 10 days have also been reported.

d. Diagnosis

3 main groups of diagnostic tests for Coronavirus and 1 specific test for SARS include:

• Rapid Molecular Genetic tests (PCR tests). However, till date the tests still have significant false negative results.
• Serological tests for antibodies. It is currently the most reliable diagnostic test. It may take 1 to 3 weeks after onset of symptoms to be reliably positive.
• Virus culture. It has now been used regularly in the major centres in Hong Kong for all suspected cases. It will take 4 to 5 days to have early results and about 7 to 8 days for definitive results.
• “Accurate Day 1 blood testing for SARS”. A new blood test for SARS which can accurately identify SARS patients from day 1 of hospital admission developed by our Medical Faculty on 23 June 2003. This is a major breakthrough substantially reduces the possibility of cross infections in hospitals, preventing outbreaks in the community, allowing quantitative monitoring of the clinical progress and prognostication of the SARS patients if it ever comes back again.

e. Prevention

Good hygiene practice remains the most effective way to minimize the risk of contracting and spreading the disease.

• Wash hands frequently, using proper hand washing technique (for details, please go to “Tips for hand washing”)
• Always carry a handkerchief or tissue paper. Cover the nose and mouth with it when sneezing or coughing. Remember to wash hands immediately with liquid soap afterwards.
• People with symptoms of respiratory tract infection or fever should wear a mask and consult a doctor promptly.
• Use serving chopsticks and spoons at meal time. Do not share lunch boxes and drinks.

f. SARS vaccination development project

Currently, there is no vaccine available. The WHO and several laboratories in China are now currently engaged in the development and evaluation of SARS vaccines.

g. Treatment

80-85% patients being treated after the onset of symptoms showed good response with a first-line treatment which includes the combination of an anti-viral drug (ribavirin) and corticosteroid plus other intensive supportive treatment.

The timing and dosage of giving the antiviral agent, steroids and other medications has been readjusted according to the observation and experience. Importance of convalescent rehabilitation for the lung function has been emphasized for the severe cases after discharge.

More scientific data and properly controlled clinical randomized studies are currently emerging to further address the issue in an evidence based approach.

h. Current Situation

The SARS outbreak in 2003 (15 Feb - 31 May 2003) in Hong Kong took a total of 299 lives and 386 Health Care Workers were infected.

According to WHO (released on 18 May 2004), the chain of human-to-human transmission appears to have been broken because of the successful isolation of the last case in China’s latest SARS outbreak.

However, WHO experts and the Chinese authorities are still trying to determine the exact cause of the outbreak. A large number of specimens were collected from possible human cases, animals and the environment during and after the SARS outbreak of 2003. The investigation has centred primarily at the National Institute of Virology in Beijing where experiments using live and inactivated SARS coronavirus have been carried out.

i. Case definitions for SARS

Suspect Case of SARS:

In accordance with WHO, symptoms and signs include:

• High fever above 38 Celsius degree, AND
• One or more respiratory symptoms1 (cough, shortness of breath, difficulty breath or hypoxia), AND
• Close contact2 with a person who has been diagnosed with SARS (in the previous 10 days)

1 In addition to fever and respiratory symptoms, SARS may be associated with other symptoms including: headache, muscular stiffness, loss of appetite, malaise, confusion, rash and diarrhea.

2 Close contact means someone who has cared for, or lived for, or has had direct contact with respiratory secretions and body fluids of a SARS patient.

Probable Case of SARS

• Radiographic evidence of pneumonia or respiratory distress syndrome, OR
• Autopsy findings consistent with respiratory distress syndrome without an identifiable cause

According to WHO, a more precise definition will be updated for longer-term surveillance.

Note

Recent reports have found that patients recovering from SARS may still have coronaviurs in the body secretion including urine and stools. It is thus strongly recommended that the discharged patient should follow closely the instructions and precautions as advised by the WHO. Up until now, no true documented cases of any cross infection from the discharged patient has been reported locally