Disasters are associated with ongoing events concerning local resources bearing potential threats to the function and the safety of a community. They are a test of the community’s capabilities to counter disasters and undertake strategies to adapt to unforeseen complications arising due to such situations. Such calamities in the form of natural or man-made disturbances affect the landscape, have an economic impact and also have an evident effect on public health. The impact of a disaster on public health is governed by efforts to improve the general welfare, promote a healthy lifestyle, and undertake research to prevent diseases and injury. The resilience of a community towards a disaster is thus defined by the resources it holds and the general measures undertaken to improve public health.
Natural disasters could pose a wide range of risks and threats on public health. They are unique in its own way and poses unique challenges to victims as well as the personnel associated with these emergency services. Thus, a balance between the ability to learn from mistakes and lessons of the past, and be on the lookout to continuously develop and innovate on measures to fight such calamities. In general, disasters are associated with different types of injuries relative to others. This acts as an important determinant to plan emergency responses, maintain a stock of medical supplies and identify the needs of a community or geographical area. It is, however, worth considering that certain injuries and impact on health are not characteristically associated with a particular disaster. Therefore, while planning strategies of response, it is necessary to address the various adverse effects the majority of the community will face due to the disaster.
The primary impact on health after a disaster is due to the sudden presence of a large number of dead bodies in a disaster inflicted area. Though, not associated with any direct impact on health, the risk of disease outbreaks following the crowding of dead bodies leading to poor sanitation, poor availability of health services and displacement of population. These factors result in the increased incidence of communicable diseases. The diseases associated with natural disasters are broadly classified as follows:
• Water-borne diseases: Diarrhoeal diseases are commonly attributed to contamination of drinking water after floods or any calamity associated with displacement of large populations. The risk of these outbreaks is more common in developing countries relative to developed countries. Similarly, the faecal-access route due to the unavailability of access to safe water and sanitation could lead to Hepatitis A and E. These are primarily endemic and could affect populations at large. Also, leptospirosis caused by zoonotic bacteria through skin contact with water, damp vegetation, or mud contaminated with rodent urine. Flooding is primarily associated with a greater risk of spread of this disease due to the higher probability of proximity of rodents to humans.
• Diseases due to crowding: Measles and the risk of transmission in disaster-stricken areas are influenced by vaccination coverage rates among individuals particularly those aged below 15 years. Lack of access to good living conditions could be associated with crowding and displacement of population in large areas following a disaster. Meningitis is also another disease transmitted from one person to another, particularly due to crowding. Acute Respiratory Infections contribute to high rates of mortality and morbidity among children aged below 5 years. Lack of access to appropriate health services and antibiotics during such situations could increase the risk of deaths.
• Vector-borne diseases: Meteorological events causing natural disasters such as cyclone, hurricane, and flooding primarily affect vector-breeding sites and lead to transmission of vector-borne diseases. The presence of the infected and affected host, fallacies in the emergency health infrastructure and disease control program may lead to the risk of developing such vector-borne diseases. To state a few, malaria and dengue transmission may be attributed to seasonal conditions such as rainfall and humidity. These outbreaks could be associated closely with living in areas with mosquito infestations, displacement of populations from unhygienic and unsafe environmental conditions to a cleaner environment and existing loopholes in emergency healthcare facilities.
• Other diseases: Tetanus caused by a bacterial toxin is primarily attributed to wound contamination especially in populations with low vaccine coverage and thereby, is detrimental to the mortality of the disease-inflicted community. Also, Coccidiomycosis, a fungal disease due to exposure to increased levels of airborne dust following landslides and earthquakes could impact public health adversely.
Other than the diseases mentioned above, there is a great risk of an affected mental health such as its symptoms are manifested much later following a disaster. It is emotionally exerting and demanding to deal with an unforeseen crisis leading to the loss of livelihood, loss of livestock including great financial savings and other issues such as the irreplaceable loss of human lives. Disasters can worsen the reproductive health of the affected population owing to high stress, overcrowded relief camps, damaged medications, and infrastructures, sexually transmitted diseases and gender-based violence. Damage to medical facilities, modern infrastructure for emergency healthcare services, and medical equipment could have a serious impact on public health.
The key to improving public health following a disaster is to be promoted through rapid surveillance and detection of epidemic-prone diseases to control their outbreak. Promoting mass immunization of children against various communicable diseases and taking measures of safety to prevent malaria, dengue, and other related conditions attributed to poor sanitation, food, and medical facilities. Appropriate strategies to improve the infrastructure for emergency medical services and their control following disasters should be implemented to improve the conditions of the victims of disasters.