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Epidemiology of Disasters

It is important to learn from the past to define priorities and make sure that essentials are dealt with first (Campbell 2005).

Different disasters produce different types of injury patterns; an understanding of disaster epidemiology is necessary to help estimate likely injury patterns, needs and timelines of response (Milsten 2000; Noji 2000). This holds not just for natural disasters but also complex health emergencies, as knowledge of their epidemiological consequences and effect on public health infrastructure should assist in planning medical personnel requirements (VanRooyen & Eliades, 2001).

A trimodal distribution of medical issues can be seen after a sudden onset disaster (Maegele et al. 2005; Taylor, Emonson & Schlimmer 1998).

The initial phase, seconds to minutes afterwards, is characterised by high mortality due to injuries not compatible with life (Maegele et al. 2005; Taylor, Emonson & Schlimmer 1998).

In the second phase, minutes to hours afterwards, medical care is focussed on early trauma management (Maegele et al. 2005; Taylor, Emonson & Schlimmer 1998). There is a ‘golden 24-hour’ period during which most casualties are recovered and when most fatalities occur (Noji et al. 2001). The main problems encountered are adequate first aid and evacuation, which have to be performed immediately by the local people (Russbach 1990). Diaster Medical Assistance Teams are rarely on site soon enough after the impact phase of the disaster to deal with the acutely injured victims (Noji 2000; Wallace 2002).

This phase also relates to the capacity of the medical and surgical system to cope with a large number of casualties (Russbach 1990).

In the third phase, occurring days to weeks after the disaster, major efforts are needed to prevent and treat complications such as sepsis, multiple organ failure and psychological problems (Maegele et al. 2005; Taylor, Emonson & Schlimmer 1998), as well as the large number of displaced persons and lack of essential resources such as safe water, food, energy and shelter (Russbach 1990).

During the post-disaster phase, trauma issues are usually related to recovery and clean-up operations or delayed medical attention due to inaccessibility. More commonly, long-term health issues, daily urgent medical needs, mental health and stress, environmental and infectious disease concerns, public health issues and special needs populations will form the bulk of health and medical issues. Primary care will need to be addressed as soon as 24 to 48 hours after the disaster (Wallace 2002).

Epidemiology of earthquakEs

The need for assistance occurs soon after an earthquake, during the ‘golden period’ when traumatic injuries predominate (Kazzi et al. 2000; Liang et al. 2001).

epidemiology of hurricanE/cyclone

After a natural disaster, a hospital ED can expect to see 3 to 5 times the normal number of patients, and during a hurricane, patient numbers can be expected to rise between 6 and 65%.

epidemiology of asian tsunami

"There are three phases of injuires; those incompatible with life occured in the first few minutes, followed by complications, including infections diseases, developing days to weeks after".

epidemiology complex health emergencies

"Trauma is not necessarily the main cause of death in disasters associated with conflict"