Clinical and epidemiological update

SARS was first recognized at the end of February 2003 in Hanoi, Viet Nam. The index case, a middle-aged man business man who has travelled extensively in South-East Asia before becoming unwell, was admitted to hospital in Hanoi on 26 February 2003 with a high fever, dry cough, myalgia and mild sore throat. Over the following 4 days he developed symptoms of adult respiratory distress syndrome, requiring ventilatory support, and severe thrombocytopenia. Despite intensive therapy he died on 13 March after being transferred to an isolation facility in Hong Kong SAR. On the basis of data from the SARS foci in Hanoi and Hong Kong SAR, the incubation period has been estimated to be 2-7 days, but usually 3-5 days. Attack rates of >56% among health care workers caring for patients with SARS is consistent in both the Hong Kong and Hanoi foci.

Case definitions

Please refer to the WHO SARS information sheet for daily information on affected areas.

Suspect case

A person presenting after 1 February 2003 with history of high fever (>38 °C)

AND one or more respiratory symptoms including cough, shortness of breath, difficulty breathing

AND one or more of the following:

• close contact, within 10 days of onset of symptoms, with a person who has been diagnosed with SARS;
• history of travel, within 10 days of onset of symptoms, to an area in which there are reported foci of transmission of SARS.

Close contact means having cared for, lived with, or had direct contact with respiratory secretions and body fluids of a person with SARS.

Probable case

A suspect case with chest X-ray findings of pneumonia or respiratory distress syndrome OR a suspect case with an unexplained respiratory illness resulting in death, with an autopsy examination demonstrating the pathology of respiratory distress syndrome without an identifiable cause.

Clinical features

The most common early symptoms in patients progressing to SARS have included fever (100%), malaise (100%), chills (97%), headache (84%), myalgia (81%), dizziness (61%), rigors (55%), cough (39%), sore throat (23%) and runny nose (23%). In many cases, patients often first presented with severe headache, dizziness and myalgia. Temperature persisted above baseline during disease progression. In some cases, there was rapid deterioration with low oxygen saturation and acute respiratory distress requiring ventilatory support. Approximately 10% of patients to date have required admission to intensive-care facilities

Chest X-ray (CXR) findings typically begin with a small, unilateral, patchy shadowing, and progress over 1ñ2 days to become bilateral and generalized, with interstitial/confluent infiltrates. Patchy CXR changes are sometimes noted in the absence of chest symptoms. Adult respiratory distress syndrome has been observed in a number of patients in the end stages.

Patients may present with a normal blood picture. However, by day 3 or 4 of the illness, lymphopenia is commonly observed ($50%) and thrombocytopenia less commonly. Elevated liver enzymes and abnormal partial prothrombin are sometimes seen. Creatinine phosphokinase is raised in some cases as is C-reactive protein.

Treatment

Hospitalized patients have received multiple antibiotic therapy. Antibiotics used alone or in combination have included azithromycin, aminoglycosides, ceftriaxone, doxycycline and ciprofloxacin. No clinical improvement has been attributable to the use of antibiotics.

The antiviral agent ribavirin, given intravenously in combination with high-dose corticosteroids, may have been responsible for some clinical improvement observed in critically ill patients in Hong Kong SAR.

Intensive and good supportive care, with and without antiviral agents, have also improved prognosis. Although the number of patients who have been discharged from hospital is very low, a significant proportion of previously critically ill patients have now stabilized and no longer require intensive care. Respiratory protection and barrier nursing are advised for all health care workers and visitors in close contact with reported cases. For more information, please refer to here.

Laboratory findings

Preliminary investigations in two patients with SARS in Germany and Hong Kong SAR have demonstrated paramyxovirusñlike particles under electron microscopy. Tests using the polymerase chain reaction technique on the same samples have also been positive. However, more samples need to be examined and further investigation undertaken before a definitive cause can be identified. Laboratories around the world are continuing to collaborate in the global effort to identify this causative agent. For information about sampling procedures please refer to here.

Sars, which stands for Severe Acute Respiratory Syndrome, is currently blighting countries in Asia, North America and, to a much lesser extent, Europe. As of April 25, the disease had killed over 250 people worldwide and infected around 4,300. Some countries are undertaking quarantine measures in a drastic attempt to control the spread of the virus. The World Health Organisation (WHO) put out a global alert on March 15, putting to the test its new global alert network set up to fight epidemics

The outbreak has been compared to the 1918-19 flu pandemic, which killed 20 million people. Sars is unlikely to claim anything like that number of victims, but because the virus is so far uncurable and spreads so quickly, it is causing a lot of concern. A vaccine could be months or even years away.

Its rapid spread has been caused principally by passengers travelling by air. The WHO has advised against non-essential travel to Hong Kong, China's Shanxi and Guangdong provinces (the latter is thought to be where the disease was first contracted), Beijing and the Canadian city of Toronto.

Last week it emerged that there have been many more cases of Sars in China than were originally reported and that the Chinese government has known about the disease since November last year. The government now concedes that the pneumonia-like virus has affected over 2,500 people and killed 112 in China alone. Last week Beijing shut down all its schools, affecting 1.7 million pupils.

How the virus spread

The spread of Sars has been traced to a doctor who travelled to Hong Kong from China. Whilst there he infected 12 people in a hotel lift who then carried the virus to countries around the world.

Curriculum links
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Symptoms

The disease has a 10-day incubation period. One of the first symptoms is a fever greater than 38°C (100.4°F). Sufferers amy think they are experiencing a bad cold. After three to seven days, a dry cough and breathing difficulties may occur. In some cases the breathing difficulties are fatal, although most sufferers do recover.

Thanks to the World Health Organisation
for much of this information.