United Nations workers grapple with SARS. (Global Health Threat).

The world's first recognized case of a deadly new disease, later named Severe Acute Respiratory Syndrome (SARS), occurred in the Guangdong Province of China on 16 November 2002. The disease is characterized by high fever and respiratory symptoms, including a dry cough, shortness of breath and difficulty in breathing, and is transmitted by face-to-face exposure to droplets released when an infected person coughs or sneezes. There is no evidence that the disease spreads through casual contact. A new pathogen, a member of the coronavirus family never before seen in humans, has now been identified as the cause of SARS.

As of 13 May, the worldwide cumulative number of reported probable cases of SARS since November 2002 has risen to 7,548, with 573 deaths, from 30 countries; of those infected, 3,298 have recovered.

On 12 March, the World Health Organization (WHO) issued its first global alert describing the disease in Viet Nam, while the Department of Health of the Hong Kong Special Administrative Region of the People's Republic of China reported an outbreak of severe respiratory disease in one of its public hospitals. WHO recommended that infected patients be isolated with barrier-nursing techniques and that any suspect case be reported to national authorities. On 26 March, 80 clinicians from 13 countries participated in a virtual conference on the treatment of SARS patients. WHO plans to hold an international meeting in Kuala Lampur, Malaysia from 17 to 18 June, to review the epidemiological, clinical management and laboratory findings on SARS and to discuss global control strategies. A report of the meeting will be posted on its web site (www.who.int/csr/sars/en/).

The WHO Global Outbreak Alert and Response Network (GOARN) was rapidly mobilized in response to the SARS outbreak involving international field support, epidemiological and clinical networking, and laboratory collaboration.

GOARN provides an operational platform for international teams on the ground in China, Hong Kong, Singapore and Viet Nam. These teams involve 60 experts representing 20 organizations and 15 nationalities working with national authorities on case management, infection control and surveillance, as well as laboratory and epidemiological investigation. Epidemiologists investigating disease transmission and clinicians treating SARS cases have come together in a global collaboration, together with 17 laboratories from nine countries which test samples from SARS patients. These international groups also participate in the WHO multi-centre collaborative networks on SARS aetiology and diagnosis (see photo).

In Viet Nam, the outbreak began with a hospitalized case of atypical pneumonia of unknown origin. The patient became ill shortly after travelling from Shanghai and Hong Kong to Hanoi. Following his admission to the hospital, approximately twenty hospital staff became ill with similar symptoms. The situation seemed to have stabilized by 21 April, following the introduction of infection-control measures. WHO officials said that while Viet Nam appears to have controlled the disease within its borders, it still faces the threat of importation of the disease from China, and the Vietnamese Government is considering closing its land border with China.

According to WHO Executive Director of Infectious Diseases Dr. David Heymann, the outbreak was well established in China, Hong Kong, Viet Nam, Singapore and Canada before WHO issued its global alert. "What we've seen is that countries who have known about SARS early on were able to raise awareness within their countries and stop local spread of that disease within their countries. So we believe that the global alert has been effective in sensitizing Governments to this disease."

Chinese authorities have reported over 1,500 cases and 56 deaths in Guangdong Province as of May, making it the most affected region. A WHO team of experts arrived in that province on 3 April and met with senior provincial health officials and discussed with health workers, including epidemiologists and clinicians treating SARS patients, patterns of transmission, clinical profiles and the suspected causative agent. On 21 April, a six-member WHO team arrived to investigate SARS in Shanghai, where two probable cases had been confirmed, and conferred with local health authorities, inspected hospitals and examined measures taken to prevent and control the disease.

The Hong Kong Department of Health on 31 March issued an unprecedented isolation order after 213 residents at the Amoy Gardens apartment complex in the Kowloon District were admitted to the hospital with suspected SARS. There had also been a number of cases in the city's Hotel Metropole.

In both places, the cases were clustered around a known case of SARS. "Something in the environment in Hong Kong, either a common system between hotels and apartments, or a common object, was transferring the disease from patients to other people", Dr. Heymann said.

On 16 April, WHO announced that it had identified a new pathogen from the coronavirus family as the cause of SARS. Coronaviruses normally lead to nothing more serious than the common cold. Scientists in the network of collaborating laboratories on 4 May reported results of the first studies to determine the survival time of the virus in different environments. They confirmed that it can survive up to 48 hours after drying on plastic surfaces and for days in human waste. According to Dr. Heymann: "The collaboration continues as top laboratory researchers have come to WHO to design the next steps, a strategy for transforming these basic research discoveries into diagnostic tools which will help us to successfully control this disease".

RELATED ARTICLE: Heartbeat: Dr. Carlo Urbani

Dr. Carlo Urbani, 46, the WHO expert on communicable diseases who first detected and reported the existence of a new infectious disease that was to become known as SARS, contracted the deadly virus while treating patients and died on 29 March in Bangkok, Thailand. He leaves behind a wife, Giuliana Chiorrini, and three children.

WHO Director-General Dr. Gro Harlem Brundtland described Dr. Urbani as an outstanding physician, adding that "his life is a reminder of our true work in public health". According to a colleague, he was in the hospital every day, talking to the staff and strengthening infection-control procedures.

Dr. Urbani, who was based in Viet Nam and also worked in public health programmes in Cambodia and Laos, identified the outbreak of the new disease in an American businessman who had been admitted to the French hospital in Hanoi on 26 February. Because of this early detection, further SARS cases were isolated and global surveillance was heightened.

While working in Mauritania before joining WHO, Dr. Urbani was the first to document the transmission of Schistoma mansoni, an infection affecting over 200 million people worldwide. In Cambodia, his work led to innovative approaches in the control of Schistosoma mekongi, a parasitic flatworm causing intestinal schistosomiasis, transmitted only on the Mekong River. If left untreated, this disease causes fibrosis of the liver and, eventually, death. He noted rocks on the river that were the natural habitat of tiny snails which act as intermediate hosts of the flatworm. He then developed a questionnaire for children, asking about rocks where they bathed, in order to identify schools where they could receive regular treatment. This method reduced the need for costly diagnosis; now children in Cambodia receive regular treatment.

Dr. Urbani received his medical degree from the University of Ancona, Italy, and did post-graduate work in malaria and medical parasitology. He was also a president of the Italian branch of Medecins Sans Frontieres.

Secretary-General Kofi Annan, in a message delivered at the memorial service for Dr. Urbani, said: "Had it not been for his recognition that the outbreak of the virus was something out of the ordinary, many more would have fallen victim to SARS" and "for his contribution on the front lines of the fight against disease, he will be remembered as a hero--in the best and truest sense of the word."

The WHO Global Outbreak Alert and Response Network (GOARN) was initiated at a major meeting of 130 experts from 72 institutions and existing networks in April 2000. GOARN is a key component of the WHO Strategy on Global Health Security, with an operational support team and an Event Management System established in Geneva and other regional hubs. Its objective is to combat the international spread of outbreaks, and it focuses on rapid identification, characterization and containment of epidemic threats, and coordinates outbreak alert and response. GOARN responded to the Ebola outbreak in Uganda in October 2000, which killed 225 persons within four months.

Point of Fact: Fatality. The likelihood of dying from SARS has been shown to depend on the profile of the cases, including the age group most affected and the presence of underlying disease, with an overall case fatality estimate of 14% to 15%. WHO estimates the case fatality ratio to be less than 1% in persons under 24 years, 6% in persons aged 25 to 44 years, 15% in persons aged 45 to 64 years, and greater than 50% in persons over 65 years.

Point of Fact: Incubation. The incubation period, which is the time from exposure to a causative agent to onset of disease, is particularly important as it forms the basis for many recommended control measures, including contact tracing and the duration of home isolation for contacts of probable SARS cases. Knowledge about the incubation period can also help physicians make diagnostic decisions about whether the presenting symptoms and clinical history of a patient point to SARS or to some other disease. WHO continues to conclude that the current best estimate of the maximum incubation period is 10 days.

Point of Fact: Isolation. A short time between onset of symptoms and isolation reduces opportunities for transmission to others. It also reduces the number of contacts requiring active follow-up, and thus relieves some of the burden on health services. Prompt hospitalization gives patients the best chance of receiving possibly life-saving care should their condition take a critical course. WHO continues to recommend the earliest possible isolation of all suspect and probable cases of SARS.