Indirect Medical Consequences of Natural Disasters - Stress Effects and Secondary Illnesses. In addition to the immediate trauma and injuries suffered by the victims of natural disasters, studies have shown that several secondary medical conditions have a higher incidence in the critical hours and days of the assessment and recovery period. In many cases, these secondary medical conditions can be attributed, at least in part, to the immense stress that is placed on individuals during a disaster situation. Disaster stress varies from situation to situation and each individual is vulnerable to different types and levels. Commonly mass evacuation of communities leads to total disruption of an individual's personal coping mechanisms. Families and neighbourhoods find themselves tossed from their homes, possibly billeting in massive temporary shelters. As shelters are usually places of last resort, individuals remain vulnerable to the lack of information and control that are awarded them. The weight of the situation is compounded by the lack of privacy and even by the isolation of natural support groups within a specific community. In the aftermath of a major natural disaster such as an earthquake where structural damage is common, an increase in acute myocardial infarctions (AMI) is not uncommon. In the Taiwan Chi-Chi Earthquake of 1999, the sudden increase of heart attacks were limited to mostly male patients and was attributed mainly to formerly sedentary individuals becoming suddenly and intensely active throughout the rescue period. It has also been suggested that the physiological "fight or flight" response that is initiated during times of perceived personal danger such as an earthquake or other natural disaster, is in of itself contributory to the increase of post catastrophe AMIs. The fight or flight response, which is a hallmark of systemic sympathetic nervous system activation, leads to an increased vulnerability to myocardial attacks in individuals with pre-existing heart disease. Along with outright heart attacks, other cardiovascular complications are increasingly seen after natural disasters such as unstable angina and potentially fatal arrhythmias. In many instances, the affect of the increased stress load is compounded with the interruption of regular medical services for pre-existing conditions such as diabetes and high cholesterol. In some instances, respiratory conditions such as allergies and asthma are aggravated after a natural disaster. This is especially true if there has been large-scale ejection of pollutants into the atmosphere as with a volcanic eruption or forest fire. Interestingly, this seems to be limited to ndividuals with pre-existing asthmatic or bronchial conditions, and heavily exposed rescue and recovery workers. In many studies, there was little to no appearance of de novo respiratory conditions among the general populace who received minimal to medium amount of exposure to the airborne irritants. Furthermore, it has been found that in the immediate aftermath of ome disasters, the actual occurrence of severe asthmatic or allergic attacks is actually decreased. After an initial decrease in incidence, respiratory illnesses start to show a substantial increase in the days to weeks after a disaster. This apparent shift in illness is attributed more to the transmission of communicable diseases such as influenza or even tuberculosis in crowded temporary shelters. Likewise, respiratory illnesses have been noted to particularly increase in the extended aftermath of a flood. As the floodwater recedes and victims reclaim their former living areas, the concentration of allergens such as dust mites climb dramatically within washed out homes, schools, and offices. Disaster stress has also been attributed to making current disease processes worse and reducing victims abilities to fight off infection. One study of rheumatoid arthritis (RA) patients showed that after an earthquake the incidence of RA activity (pain, stiffness, and swelling) increased dramatically. It has also been shown that due to the common occurrence of dehydration, malnutrition, break down of public health safe guards, and stress and anxiety in the aftermath of natural disaster, an individual is more prone to serious infection from a familiar vector. Including disease vectors which under normal circumstances would be non-pathogenic. In many cases, while the stress of a natural disaster is felt immediately by the victims, the impacts upon their health take days to weeks to surface. This is common with the psychological impacts of catastrophes. In the weeks and months following a disaster event, many patients will suffer from such psychological disorders such as post-traumatic stress disorder (PTSD) or general anxiety disorder (GAD). In many instances victims and survivors compla in of some of the following symptoms: night terrors, sudden phobias, grief, depression, guilt, insomnia, loss of appetite or flashbacks and hallucinations. It is common for many behavioural responses - to disasters and catastrophic events - to remain subtly buried within a victim's coping mechanisms, surfacing only under close observation of key health related habits such as sleeping, eating, smoking, or alcohol consumption. Psychological recovery from lapses in mental health, brought on by catastrophic circumstances, is dependent upon the timely recognition of faint symptoms and the availability of the appropriate resources which can be used to promote healing. As populations in high-risk areas begin to increase in density, the potential for mass casualty natural disasters rises. In the event of a catastrophe with perhaps thousands of victims, the sheer volume would overload local response mechanisms. This would compound any existing stresses and pressures that surviving victims would face after an emergency. Scarce essential resources would now have to be shared between a greater number of victims. Volunteers and health professionals would have less time to spend on each individual. Generally, the severity of secondary medical conditions, many of which can be in part attributed to stress, is directly dependent on the size of the disaster and the community's ability to cope with, and recover from the devastation.