26 September 2003
Poor Plumbing a Likely Cause of SARS Spread, U.N. Health Group
Theory explains rapid transmission in Hong Kong
A team of disease detectives working to understand more about
severe acute respiratory syndrome (SARS) reports that poor plumbing
may have caused rapid SARS transmission earlier this year in a
Hong Kong apartment building. The World Health Organization (WHO)
released those results of a technical consultation in a September
26 press release.
The findings also indicate that poorly designed or maintained
plumbing could contribute to the spread of other diseases that
are transmitted by highly infectious fecal droplets.
In the Hong Kong case during the 2003 SARS outbreak, it is now
suspected that virus carrying fecal droplets spread through multiple
apartments via sewage and drainage systems with strong upward air
flows and inadequate seals. The committee does point out that most
SARS cases appeared to be spread during close face-to-face contact.
The WHO report finds that building conditions in many countries
may expose residents to dangerous sewage. "Fortunately, solutions
are simple and already in place in most areas worldwide, but there
remain places where shortcuts in design, construction and maintenance
continue to compromise safety," said Dr. Jamie Bartram, head of
WHO's Water, Sanitation and Health Program.
Following is the text of the press release:
WORLD HEALTH ORGANIZATION
September 26, 2003
Inadequate plumbing systems likely contributed to SARS transmission
GENEVA AND ROME -- Inadequate plumbing is likely to have been
a contributor to the spread of SARS in residential buildings in
Hong Kong Special Administrative Region of China, a World Health
Organization (WHO) technical Consultation concluded today. It also
contributes to the spread of a number of other infectious diseases
in several other countries. In the absence of proper maintenance
and without consistent monitoring, reviewing, enforcing and updating
of building standards and practices, inadequate plumbing and sewage
systems could continue to enhance the potential of SARS and some
other diseases to spread. The meeting concluded that it would be
relatively easy to interrupt and avoid some diseases, including
SARS if it were to return.
The Consultation developed a checklist of environmental hygiene
factors in building design and maintenance that, if followed, could
contribute to controlling environmental transmission of SARS Coronavirus
(CoV) and other viruses. Viruses that can be transmitted by the "faecal
droplet" route also include gastro-enteritis virus (such as Norwalk-like
viruses), some adenoviruses and enteroviruses responsible for a
number of gastro-intestinal and neurological diseases.
"With this Consultation, WHO is helping its Member States appreciate
the need to assess and manage the health risks associated with
inadequate plumbing and sewage systems. It has documented lessons
learned, it has pointed to risk assessment and management tools
to be better prepared in case of future outbreaks and it has listed
concrete measures and regulatory frameworks for the prevention
of faecal droplet transmission of disease-causing viruses, This
information will be brought together in a guidelines document," commented
Dr Jamie Bartram, Head of WHO's Water, Sanitation and Health Programme
at its Geneva headquarters.
It has been suggested that the "faecal droplet" route may have
been one of several modes of transmission in Hong Kong during the
SARS outbreak in early 2003. In this case, droplets originating
from virus-rich excreta in a given building's drainage system re-entered
into resident's apartments via sewage and drainage systems where
there were strong upward air flows, inadequate "traps" and non-functional
Meeting in Rome, an international group of WHO experts reviewed
the transmission risks related to the current state of plumbing
systems around the world and how inadequate construction and maintenance
practices could contribute to the spread of SARS.
"In many countries there will be buildings where keeping sewage
separate from building occupants is a critical challenge," observed
Dr Bartram. "This could result in harmful viruses, including the
SARS Coronavirus (CoV), being sucked from the sewage system into
the home if, for example, there are strong extractor fans working
in a family's bathroom. Fortunately, solutions are simple and already
in place in most areas world-wide, but there remain places where
short-cuts in design, construction and maintenance continue to
While the evidence suggests that, under most circumstances, the
spread of SARS among people occurred overwhelmingly across a short
range of distance through water droplets, there are specific situations
where conditions allowed other transmission routes. One of these
is through sewage-associated faecal droplets and this Consultation
has, therefore, recommended measures to reduce sewage-borne transmission
routes of pathogenic viruses," added Dr Bartram.
The Consultation emphasized that the solution - proper plumbing
- is a simple public health measure which is often overlooked but
can be addressed at minimal extra cost. Nevertheless, it is a significant
tool in stopping faecal droplet transmission of disease.
The Consultation resolved that Governments establish or strengthen
intersectoral arrangements and mechanisms to enhance joint efforts
of ministries of health, building authorities, local governments
and architects/designers to both raise general awareness of the
risks from inadequate plumbing and sewage systems, and to take
concrete actions to address shortcomings in this area.
The experts meeting at the WHO European Centre for Environment
and Health in Rome came from nine countries and represented the
fields of epidemiology, virology, environmental health, risk assessment/management,
building design and plumbing.