Preparing for and Responding to Infectious Disease Threats Following Hurricanes

November 22, 2022 | Amelia Poulin-Obregon, Sidnie Christian

Hurricanes often conjure images of strong winds, intense floods, and unrelenting rain that can cause immediate destruction. However, a silent threat also lurks in the wake of a hurricane: the risk of disease transmission.

Hurricanes facilitate the spread of a wide variety of infectious diseases through flooding, population displacement, and overcrowding. In a hurricane’s aftermath, health agencies often must take steps to prevent infectious disease spread, including through mitigating disease risks of contaminated water, establishing surveillance systems, vaccinating those at high risk for infection, communicating risk effectively, and monitoring endemic diseases.

Infectious Disease Threats Following Hurricanes

Following a hurricane, the risk of exposure to infectious disease increases due, in part, to the presence of floodwater and debris. Hurricanes may contribute to population displacement and overcrowding—further heightening risk factors for respiratory diseases—as well as cause damage to healthcare facilities.

Vector-Borne Diseases

Following a hurricane, rodents may scavenge through left-behind garbage and debris. Rodent feces can carry a range of bacterial and gastrointestinal illnesses, which leaves rodents prone to spreading disease as they move between food sources. Likewise, leptospirosis, a bacterial disease that can spread when floodwaters are contaminated by the urine of an infected animal—usually rats.

Water-Borne Diseases

Drinking water can become contaminated following a hurricane as pipelines crack or break, or sewage spills contaminate water lines. Contaminated water may carry diseases such as hepatitis A, e. coli, salmonella, and norovirus. Contaminated drinking water is a significant health risk especially among infants, children, older adults, and those with weakened immune systems.

Respiratory Diseases

Hurricane shelters can create conditions that increase the spread of respiratory illnesses due to overcrowding, reduced hygiene, and limited resources. Acute respiratory infections are a major cause of illness and death among displaced populations, particularly in children less than five years of age. In shelter settings, communicable respiratory diseases such as COVID-19, influenza, and the common cold are of great concern. The lack of access to health services and treatment options further increases the risk for death from acute respiratory infections.

Wounds, Injuries, and Other Dermatologic Issues

Transportation issues, power outages, and property damages can limit access to healthcare facilities, putting people at increased risk of infection. Those who present with wounds and injuries in the aftermath of a hurricane are at increased risk for disease, especially from contact with floodwaters, stormwater run-off, and disrupted sewage systems. With limited-to-no access to healthcare, those with open wounds and exposure to contaminated waters can develop severe and potentially life-threatening skin infections. For example, tetanus is a fatal disease that can be acquired from a wound. While exposure to floodwaters alone does not increase the risk of tetanus, some people impacted by floods may be at increased risk for developing tetanus through contact with flood waters or eroded soil. More recently, after Hurricane Ian struck Florida earlier this year, there were reports of a rise in flesh-eating bacteria throughout the state.

Key Considerations for State and Territorial Health Agencies

Several infectious diseases may threaten the public’s health post-hurricane. however, health agencies may take some cross-cutting actions to address these threats.

Mitigate Disease Risks of Contaminated Water

Waterborne infections may cause diarrheal disease, posing a large threat to the public’s health. Health agencies may need to engage cross-sector partners to prepare for and respond to sanitation issues, including advising landfill and waste facility operators to take steps to reduce potential leakage and contamination. Consider communicating to residents the importance of having clean water available and share steps that residents may take to disinfect water. The resource below shares additional information:

• Drinking Water Advisory Communication Toolbox - Water, Sanitation, & Hygiene-Related Emergencies & Outbreaks

Establish Surveillance Systems

The risk for infectious disease transmission may increase as evacuation centers become crowded. Health agencies may need to rapidly develop surveillance systems to track morbidity and mortality in alternative housing sites. The resources below detail how surveillance systems were rapidly deployed during Hurricanes Katrina and Sandy.

• Challenges to Implementing Communicable Disease Surveillance in New York City Evacuation Shelters After Hurricane Sandy
• Emerging Disease Syndromic Surveillance for Hurricane Katrina Evacuees Seeking Shelter in Houston's Astrodome and Reliant Park Complex

Health agencies may also need to take special populations (e.g., pregnant people) into consideration during infectious disease surveillance, which may include pairing records from infants and birthing parents to monitor outcomes. For more information on strategies that affect family health, visit the ASTHOReport, Considerations for Maternal Child Health Policies and Public Health Emergencies.

Vaccinate Those at High Risk for Infection

While it may not be necessary to implement large campaigns, health agencies may consider sharing guidance on testing, vaccination, and treatment for infectious diseases that may proliferate in the aftermath of a hurricane. For example, tetanus may pose a risk to emergency responders or residents with open wounds who have come into contact with contaminated flood water. Evacuees living in crowded settings may also benefit from influenza, varicella, and MMR vaccination, as well as hepatitis A, if exposed. For more information, visit the CDC webpage, Interim Immunization Recommendations for Individuals Displaced by a Disaster.

Communicate Risk Effectively

When communicating a risk to the public, health agencies can use key principles to effectively share a message. CDC’s Crisis and Emergency Risk Communication toolkit shares tips such as: be first, be right, be credible, express empathy, promote action, and show respect. More information is available at the resources below:

• Emergency Preparedness and Response: Manuals and Tools
• CERC in a Hurricane Response
• CERC in an Infectious Disease Outbreak
• Preparedness and Safety Messaging for Hurricanes, Floods, and Similar Disasters

While emerging infectious disease threats are often the focus post-hurricane, it is important to keep in mind how disruptions to healthcare systems may affect other disease areas. For example:

• COVID-19: Health agencies should consider sharing guidance on how to stay safe from COVID-19 during hurricane evacuations. This may include having additional COVID-19 tests available and taking other prevention measures, as well as having a plan in place if someone becomes sick with COVID-19. For more information, visit the CDC webpage on hurricanes and COVID-19.
• HIV: Hurricane evacuees living with HIV may experience disruption in care and may temporarily lose access to treatment. For example, in Puerto Rico following Hurricane Maria, access to care was reduced by 22%, and viral suppression decreased from 71% to 65%. The common infectious diseases that often follow from a hurricane may have more severe outcomes in people who are immunocompromised. Health agencies should consider communicating strategies for obtaining antiretroviral therapy post-evacuation, and provide guidance to providers.