LEGIONELLA - World Health Organization

The number of samples collected can be considerable, and it will often be necessary to use
more than one laboratory to ensure that all the samples are processed in good time. If this is
the case, the outbreak control team should ensure that the laboratories used are competent and
experienced, and use the same method of detection, with the required sensitivity. The outbreak
plan, which should be prepared in advance, should include information on:
• roles that individuals may play
• laboratories that are to be used
• contingency plans for situations in which the local laboratory cannot cope
• means to rapidly obtain sufficient laboratory media
• transport arrangements for specimens, to ensure arrival within the recommended time.
Chapter 11 has detailed information on sampling for legionellae. Advice on sampling that
complies with the European and United Kingdom guidelines has recently been published
and is freely available from the Internet (Standing Committee of Analysts, 2005).
9.3.6 High-profile outbreaks
Occasionally, outbreaks may be of such magnitude or importance that all investigations
should be managed from an incident room established within a national public health institution.
In such cases, resources must be identified, because many staff may be required for:
• interviewing patients
• carrying out a case–control study to determine the epidemiological importance of certain
risk factors
• collecting and processing clinical and environmental samples.
These staff will not be part of the outbreak control team but must be briefed regularly to ensure
that all resources required for the outbreak investigation are used efficiently and effectively.
Regular updates of factors such as case ascertainment, patient outcomes and environmental
results must be conveyed to all core members of the outbreak control team. This does not
necessarily mean convening meetings; it can be achieved using e-mail groups, video conferencing
or telephone and fax communications by the chairperson of the outbreak control team.
Where there is an international dimension, the relevant health departments in overseas
governments, the relevant department in WHO, 22 and other stakeholders and institutions must
be informed. Case searching and follow-up must be organized through national public health
institutions.
22 outbreak@who.int
LEGIONELLA AND THE PREVENTION OF LEGIONELLOSIS