South-East Asia Regional Conference on Epidemiology

28 | <strong>South</strong>-<strong>East</strong> <strong>Asia</strong> <strong>Regional</strong> <strong>Conference</strong> on Epidemiology
put their political will behind re-beginning of polio vaccination in northern Nigeria. Religious leaders
from around the world also began to issue declarations (fatwas) and actually visited northern Nigeria
to get polio eradication back on track. It is back on track, although polio continues, at times, to spread
from Nigeria to neighbouring countries.
Another issue in which a pathogen has been held hostage in south-east <strong>Asia</strong> Region is H5H1. The
Minister of Health of Indonesia noted that, in many instances, those countries that freely share virus
samples do not have access to vaccines, which are made with the knowledge derived from those virus
samples. This virus has been used as a means of leverage to see if there is a mechanism that can be
developed to make sure that vaccine is provided to countries on a more equitable basis. This resulted
in a World Health Assembly resolution in May 2007 that led to a series of intergovernmental meetings
that are still going on, to address virus-sharing and access to vaccines. Many might say that it is not
right to hold the pathogen hostage, but whatever is one’s opinion, the issue raised in Indonesia is valid
and needs to be addressed by the global community.
Epidemiology in the future needs to be prepared for Swiss cheese events. Swiss cheese is a cheese
with many holes in it (Fig. 5). If there are four pieces of Swiss cheese and one wants to pass an arrow
through those four pieces, the holes need to be lined up. That is exactly what needs to be learnt in
future in epidemiology, i.e. lining up the holes in advance. Several risk factors that are occurring can
align in such a way that a public health event occurs.
The Rift Valley Fever outbreak in Sudan in 1998 has given us a glimpse of the future in epidemiology.
A major outbreak of Rift Valley Fever occurred in <strong>East</strong> Africa in 1998 because of a series of Swiss
cheese events. First, there was an El Nino event which caused flooding. When flooding occurs,
humans and animals move closer together. As they move closer together their contact is increased.
At the same time, the water gives space for mosquito breeding. These three events - a disease carried
by cattle, which transmits to humans either during a butchering process or from human-to-human by
mosquito - were all occurring; and three holes were lining up. There were more holes in that Swiss
Fig. 5: Epidemiology in the future: be prepared for Swiss cheese events
Source: James Reason: Human error: models and management BMJ 2000;320:768-770