Other Biological Hazards and Infectious Agents

Heavy rains during or after a tornado may result in flooding or standing water. Floodwater and standing waters often contains infectious organisms including gastrointestinal bacteria such as E. coli, Salmonella, and Shigella; hepatitis A virus; and agents of typhoid, paratyphoid, and tetanus. Moreover, pools of standing or stagnant water can become breeding grounds for mosquitoes, increasing the risk of encephalitis, West Nile virus, Zika, or other mosquito-borne diseases. The presence of wild or stray animals in populated areas increases the risk of diseases caused by animal bites (e.g., rabies) as well as diseases carried by fleas and ticks. 

To avoid bacterial and viral exposures, keep children and pets out of standing water and contaminated materials. Hands should be cleaned regularly by either hand-washing with soap and water or using an alcohol-based hand sanitizer (containing 60%-95% alcohol). When hands are visibly soiled or dirty, it is best to wash your hands with soap and clean running water for 20 seconds.  

To protect yourself and your family from animal- and insect-related hazards, avoid wild or stray animals, use insect repellent that contains DEET or picaridin, and wear long pants, socks, and long-sleeved shirts. Drain standing water in open containers to minimize mosquito breeding places.  

Livestock might no longer be confined after a disaster, and the pollution they generate may contaminate surface waters used for drinking. Loose dogs or other roaming animals may be lost, frightened, or hurt, and more likely to bite. The CDC recommends that you not feed, approach, or call a dog you do not know.  

Rats and mice can spread disease, contaminate food, and destroy property. Remove food sources and other items that can provide shelter for rodents. Keep food and water (including pet food) in containers made of thick plastic, glass, or metal that have a tight-fitting lid to keep rodents out. For more information, see the following:  

Contaminated drinking water is the top reason for illness after most disasters. If municipal water sources have been impacted, use one of the following for handwashing, drinking, teeth-brushing, and cleaning children’s toys: 

  • Bottled water

  • Water that has been boiled for one minute then cooled

  • Water that has been disinfected with 1/8 teaspoon of household bleach per 1 gallon of water or 1/4 teaspoon per gallon of cloudy water (allow it to stand for 30 minutes before use)   

The following are resources for home and small business owners: 

Technical resources for the IH include: 

  • Centers for Disease Control and Prevention: “Infectious disease and dermatologic conditions in evacuees and rescue workers after Hurricane Katrina - multiple states, August-September, 2005.”
    MMWR 54:961 (2005).

  • Cummings, K.J., J. Cox-Ganser, M.A. Riggs, N. Edwards, G.R.Hobbs, and K. Kreiss: “Health effects of exposure to water-damaged New Orleans homes six months after hurricanes Katrina and Rita.” Am J Public Health 98:869‒875 (2008).

  • Emerson, J.B., P.B. Keady, T.E. Brewer, N. Clements, E.E. Morgan, J. Awerbuch, and N. Fierer: “Impacts of flood damage on airborne bacteria and fungi in homes after the 2013 Colorado Front Range flood.” Environ Sci Technol 49:2675‒2684 (2015).

  • Jones, E.K., K.G. Sumner, and M. Gochfeld: “Residential flood damage after hurricane Floyd, mold, household remediation, and respiratory health.” Remediation J 24:107‒120 (2013).

  • Ligon, B.L.: “Infectious diseases that pose specific challenges after natural disasters: a review.” Semin Pediatr Infect Dis 17:36‒45 (2006).

  • Lin, C.J., T.J. Wade, and E.D. Hilborn: “Flooding and Clostridium difficile infection: a case-crossover analysis.” Int J Environ Research Public Health 12:6948‒6964 (2015).

  • McKenzie, L.B., N. Ahir, U. Stolz, and N.G. Nelson: “Household cleaning product-related injuries treated in U.S. emergency departments in 1990–2006.” Pediatrics 126:509‒16 (2010).