How the SARS outbreak started

Citation

Finch, E. (2003), "How the SARS outbreak started", Facilities, Vol. 21 No. 7/8. https://doi.org/10.1108/f.2003.06921gaa.001

How the SARS outbreak started

How the SARS outbreak started

On 14 March 2003, a 33-year-old man visited his brother who owned a flat in Block E of Amoy Gardens in Hong Kong. He had diarrhoea at the time; a consequence of a chronic renal disease for which he was being treated at the Prince of Wales Hospital. By 15 April, only one month later, there were a total of 321 people in Amoy Gardens suffering from atypical pneumonia, or what has more commonly now become labelled SARS.

Most of the cases were concentrated in Block E, accounting for 41 per cent of the total number of incidence in the outbreak. Block C (15 per cent), Block B (13 per cent) and Block D (13 per cent) recorded the second, third and fourth highest incidence of SARS infections. Each of the blocks in Amoy Gardens had 33 floors with eight apartments on each floor. Floors 10 and above were more affected than the lower floors. Block E cases appeared earlier in the outbreak and showed a point-source type of distribution. Cases in the other blocks which appeared three days later were more evenly spread.

Environmental investigations into the spread soon focused on the sewerage system. Each block had eight vertical soil stacks each collecting effluent from the same unit of all floors. In turn, the soil stacks were connected to water closets, wash basins, bathtubs and the bathroom floor drains. Each of the sanitary fixtures was fitted with a U-shaped water trap to prevent odours and insects from entering the toilets. To be effective, these U-traps needed to be sufficiently filled with water. However, interviews with tenants revealed complaints about foul smells in the toilets suggesting that the U-traps were not functioning properly. Most householders chose to clean the bathroom floor by mopping instead of flushing it with water. As a consequence the U-traps connected to the floor drains were likely to be dry and would not have functioned properly. It was suggested by the environmental investigation that a reflux of air from the soil stack into the bathrooms may have carried contaminated droplets of sewage. This could explain the point-source spread of SARS in Block E.

From a facilities management perspective what does this outbreak tell us? Certainly it shows how unanticipated use of the building can give rise to undesirable consequences. Assumptions about the method of cleaning (not the use of mops) led to a sanitary solution that was ineffective. The consequences were fast and lethal. The pattern of disease spread vertically rather than a more typical horizontal spread, providing strong evidence that a vertical pipe system was responsible. However it required an investigative team of disparate disciplines, including experts from the Buildings Department, Environmental Protection, Food and Environmental Hygiene, Water Services Department and the Drainage Services Department. This is typical of many health-related phenomena today where the design and operation of the facility plays such an important part in its spread. The SARS case highlights that an integrated view of building use is required to understand these phenomenon, encompassing user behaviour, environmental systems and building layout. Facilities management needs to have a much wider reach than just "bricks and mortar" to prevent or deal with effectively such incidents.

In a world of dense populations and extensive travel, the threat of disease is greater than ever. SARS is symptomatic of a number of different infections that are likely to challenge our habits and the way we live. Barriers to the free-flow of infection include international barriers: but more importantly, the barrier of the apartment or the office may become increasingly important. Today we all understand the concept of compartmentation to minimise the risk of fire spread. Exactly the same philosophy may well become part of our approach to the prevention of the spread of disease. Facilities managers will have to embrace a very broad view of issues in order to meet the challenge of SARS and other airborne diseases.

For a full description of the Amoy Gardens outbreak visit: www.info.gov.hk/dh/ap.htm "Main findings of an investigation into the outbreak of Severe Acute Respiratory Syndrome at Amoy Gardens" produced by the Department of Health, Hong Kong.

Edward Finch