Disaster Epidemiology FAQs

From the standpoint of public health, a disaster is defined based on its consequences on health and health services. A disaster is a serious disruption of the functioning of society, causing widespread human, material, or environmental losses, that exceed the local capacity to respond, and calls for external assistance. Based on this definition, disasters could be any emergency (man-made or natural) that exceeds the local capacity to respond. In addition, what may constitute a disaster in one community may not be in another.

Collecting health and needs information during a disaster helps to provide situational awareness. This information provides a better understanding of the immediate needs required, how the response should be planned, and the appropriate resources required. There is a need to know what is happening to understand what the needs are, plan the response, and gather the appropriate resources. The prevention of further morbidity and mortality requires addressing both immediate and long-term needs, adjusting priorities, allocating resources, and projecting and planning for the future. Data collected is also used to identify risk factors and improve prevention and mitigation strategies for future disasters.

Disaster epidemiology involves the assessment of the short- and long-term adverse health effects of disasters and the predicted consequences of future disasters. It provides situational awareness by providing information that enables a better understanding of what the needs are, how to plan the response, and what appropriate resources are required. Typically, the main objectives of disaster epidemiology are to:

1. Prevent or reduce the number of deaths, illnesses, and injuries caused by disasters,
2. provide timely and accurate health information for decision-makers, and
3. improve prevention and mitigation strategies for future disasters and prepare future response plans based on the information gained.

The Texas Department of State Health Services provides expertise in Public Health Emergency Preparedness and Community Assessment for Public Health Emergency Response during a disaster.

Local health departments should identify current tools in place for non-disaster settings to assess their applicability and adaptability to a disaster response setting. The Texas Department of State Health Services also provides various tools for public health disaster response, including template forms for general shelter surveillance, mortality surveillance, and a Community Assessment for Public Health Emergency Response (CASPER). The Centers for Disease Control and Prevention (CDC) provides various tools on their website.

The Texas Department of State Health Services (DSHS) provides scientific consultation, technical assistance, and disaster epidemiology training to local, tribal, and other public health partners to help them respond to natural and man-made disasters. Please contact the regional office in which you are located to request DSHS assistance. View information on regional offices.

The Centers for Disease Control and Prevention (CDC) provides information on disaster epidemiology.

Disaster management cycles include a pre-disaster period, a disaster period, and a post-disaster period. During each phase of the disaster cycle, opportunities exist to implement specific epidemiologic activities. During the pre-disaster phase, epidemiologists may conduct epidemiologic investigations and evaluation studies. During the disaster period, epidemiologists may conduct rapid needs assessments (i.e., CASPERs) and establish surveillance activities. During the post-disaster phase, epidemiologists may integrate data obtained on environmental hazards, environmental exposures, and health outcomes (tracking), as well as track affected/exposed people for medium- to long-term health consequences (registries). 

Public health surveillance is the ongoing, systematic collection, analysis, and interpretation of deaths, injuries, and illnesses relating to the adverse health outcomes of a disaster incident in a community. It allows for the human health impacts of a disaster to be assessed and the identification of potential problems in existing planning and prevention strategies.

Public health morbidity surveillance enables the identification of disease and injury outbreaks and the tracking of disease and injury trends. A common myth is that epidemics are inevitable during a disaster. In contrast, early detection and an effective response plan can serve to prevent the occurrence of an outbreak. In addition, health surveillance provides information to make informed decisions about action items such as allocating resources, targeting interventions to meet specific needs, and planning for future disasters. Public health morbidity and mortality surveillance can also act to identify intervention strategies for minimizing future deaths or injuries. In addition, syndromic surveillance is a potential data source from emergency rooms to monitor such conditions as carbon monoxide poisoning, hyperthermia, and hypothermia. Further, there is growing recognition of the need to collect mental health surveillance data in the context of disaster response. The number of deaths is a strong indicator of the impact of the disaster. Disasters may overwhelm local medical examiners/justices of the peace and emergency systems, disrupting typical reporting methods. Implementing active mortality surveillance following a disaster helps to alleviate this disruption and serves as a critical aspect of the response.

The Texas Department of State Health Services (DSHS) has developed multiple ready-to-use templates for mortality and general shelter surveillance. These tools can be used to supplement existing surveillance systems or replace surveillance systems that have been hindered or destroyed due to a disaster.

During disasters, several steps may need to be conducted simultaneously when planning a surveillance system. Just as purpose and objective should be clear in any disaster response effort, the surveillance system must also have well-defined objectives. Additionally, data sources need to be identified and selected. Although facility-based surveillance of hospitals and emergency medical operations can provide information on those seeking care during a disaster, additional nontraditional sources of information may also be required (such as a shelter, pharmacies, or physician offices). Ideally, data collection instruments for surveillance should be developed, tested, and distributed before the disaster occurs. However, these instruments will need to be modified for each disaster and location. The data collection instrument should collect only the most essential information and involve easy data entry. For information to be useful, it must be disseminated in a timely fashion through the appropriate channels (e.g., public health and other government officials, relief workers, the affected community, and the media).

Possible places include hospital emergency departments, shelters (general and special needs), first-aid stations, and medical examiners/justices of the peace (coroners).

There are a variety of data that may be collected during a disaster, including:

1. Numbers of individuals impacted by the disaster
2. Demographic information (e.g., age, gender) from individuals and households
3. Medical conditions and injuries related to or exacerbated by the disaster
4. Individual and household medical and public health needs post-disaster
5. Information on individual and household experiences during the disaster (e.g., where they were, what they were doing)
6. Information on whether people had received/were receiving public health and/or government messages about evacuation, safety, community resources, etc.
7. Medical and public health facilities impacted by the disaster
8. Types of medical treatment given to disaster victims
9. Public health resources distributed and consumed by disaster victims (e.g., vaccinations, medical supplies, other mass-distributed supplies).

There are a variety of places where data may be collected, including:

1. Administrative data and/or medical records from hospitals, emergency rooms, mobile medical units, and urgent care facilities
2. Surveys of medical professionals or public health employees
3. Syndromic surveillance data from emergency rooms
4. Registration logs from shelters, medical facilities, and supply distribution centers
5. Surveys of individuals who utilize shelters, medical facilities, and supply distribution centers
6. Responding agencies (e.g., FEMA, American Red Cross)
7. Other surveys of disaster victims.

The Centers for Disease Control and Prevention (CDC) Division of Environmental Hazards and Health Effects, Health Studies Branch has developed the CASPER toolkit to assist personnel from any local, state/territorial, regional, or federal public health department with conducting a community needs assessment. CASPER is an epidemiologic technique designed to provide a quick and low-cost household-based information assessment of an affected community’s needs after a disaster in a simple format for decision-makers. To learn more information about CASPER, visit the Texas Department of State Health Services’ CASPER website or CDC;s website.

In short, yes. CASPER is a type of rapid needs assessment. CASPER is designed to provide accurate and timely data through precise analysis and interpretation for decision-makers. Gathering health and basic needs information using valid statistical methods allows public health and emergency managers to prioritize their responses and make informed decisions regarding the distribution of resources.

The primary goals of the CASPER are to rapidly obtain information about the needs of an affected community and to assess changes in needs during the recovery period. The main objectives of CASPER are to:

1. produce household-based population estimates of needs for decision-makers,
2. determine the critical health needs and assess the impact of the disaster on the community,
3. characterize the population residing in the disaster area, including any ongoing health effects, and
4. evaluate the effectiveness of relief efforts using follow-up CASPER.

CASPER is not intended to deliver food, medicine, medical services, or other resources to the affected area, or to provide direct services to residents, such as cleanup or home repair.

During a disaster, the local or regional health departments or emergency managers may decide to initiate a CASPER when at least one of the following conditions occurs:

1. the effect of the disaster on the population is unknown,
2. the health status and basics needs of the affected population are unknown, or
3. when response and recovery efforts need to be evaluated.

Although the Texas Department of State Health Services typically provides technical assistance during a disaster response, the CASPER methodology can be used in both a disaster and non-disaster setting. CASPER methodology has been used to assess public health perceptions and estimate the needs of a community during a non-disaster setting. Regardless of the setting and objectives, once the decision to conduct the CASPER has been made, it should be initiated as soon as possible.

The Texas Department of State Health Services has a website that provides more information on CASPER. In addition, the CDC has developed the CASPER toolkit to assist personnel from any local, state/territorial, regional, or federal public health department in conducting a CASPER during a disaster. The toolkit was developed to standardize the assessment procedures. While it is focused on disaster response, it may also be adapted for use in non-disaster settings. The CASPER toolkit provides guidelines on questionnaire development, methodology, sample selection, training, data collection, analysis, and report writing, and is available at the CDC website.

If you would like technical assistance from the Texas Department of State Health Services in conducting a CASPER within your jurisdiction, please contact the regional office in which you are located. Find more information on the location of regional offices. 

These community assessments provide valid, credible information about communities and help to define the scope and magnitude of specific public health needs or issues. A report containing initial results and recommendations is provided within 48 hours after data collection; this timely report enables local officials to make decisions quickly. Actions may include but are not limited to, prioritization of resources, public health messaging, enhanced health surveillance, or public health interventions. View more information.