By: Heather Williams

Hurricane Harvey has made his mark on the Southern parts of Texas and making its way toward Louisiana.  Even after the winds die down and the rain stops falling, the threat is not over.  Danger lurks in the water that has filled our communities.  Many pathogens are floating around and measures should be taken to prevent illness as a result of ingestion, infection, and transmission of disease.  But what exactly should we be looking out for and vigilant against?


Gastrointestinal (GI) infections are a great concern in the aftermath of a natural disaster.  These infections could come from parasites, bacteria, or even viruses.  During a storm event such as this, access to clean water to wash hands may be limited.  Additionally, there may be many times when people inadvertently put their hands or other objects in their mouth to do things and not think about the consequences.  This allows contaminated water to enter the body and take over the GI tract.

Giardia, a microscopic parasite found in food, water, soil, and surfaces contaminated with feces of infected humans and animals.  Giardia can cause prolonged diarrhea and continue to be contagious with poor sanitation and handwashing ability.  The most common mode of transmission is through contaminated water.  Unfortunately, its body is made of a protective outer shell that allows it to survive outside the body for long periods of time.  This protective shell also makes it tolerant to chlorine disinfection.

Cryptosporidium, or Crytpo is another GI parasite known to cause a diarrheal disease known as cryptosporidiosis.  The most common mode of transmission is through contaminated water.  While many species of Crypto infect animals, some can also infect humans.  In fact, Cryptosporidium is a leading cause of waterborne disease in the United States among humans.  It too has a protective outer shell that allows it to survive long periods outside of the body and tolerant to chlorine disinfection.

Leptospirosis, while infrequently seen, is a bacteria found in water and can be transmitted through the urine of infected animals.  This bacteria can infect both humans and dogs and result in liver or kidney failure. While outbreaks are fairly rare in the United States, they are almost always created after a flood event.  In fact, 50% of the infections that occur in the United States come from Hawaii where flood waters in towns carry a higher risk of infection.

E. coli, Shigella, and Salmonella, are bacterial infections that can be transmitted through contaminated water. During the aftermath of an extreme flooding event, the public water system may become overwhelmed. Untreated water may make its way to peoples’ homes causing waterborne bacterial infections.

Cholera, while rare in the United States, is known to live in brackish waters.  These are areas that are not quite freshwater, but not completely saltwater.  A tropical event such as a hurricane could bring in this virus from the Gulf of Mexico.  Cholera causes acute diarrhea, vomiting, and leg cramps.

Norovirus, is a highly contagious GI virus transmitted via fecal-oral route.  Norovirus becomes prolific in places where handwashing is not readily available, but can also be spread through contaminated water.  Norovirus may also contaminate untreated drinking water.

Hepatitis A, is a virus that can be transmitted through contaminated drinking water from sewage runoff or from an infected person without proper handwashing.  Children often do not show symptoms, but adults begin to show symptoms between 2 and 6 weeks after infection.  Symptoms include jaundice (yellowing of skin and eyes), dark urine, nausea vomiting, and stomach pain among others.


Infection is a very serious threat during and after a natural disaster.  It is easy to injure yourself and new or existing wounds can easily be infected with some very nasty bacteria.  Tetanus, trench foot, and Vibrio are major causes of concern.

Tetanus is a disease caused by a puncture wound infected with contaminated soil or water.  Use caution when walking in areas with debris or through water that you cannot see through.  Luckily tetanus is vaccine preventable and treatable, but very serious if ignored.

Trench Foot is a skin infection caused by prolonged immersion in unclean water.  This can lead to gangrene or even require amputation.  While this ailment became famous in World War I when soldiers were stuck in the trenches for extreme amount of time, it is a modern ailment of rescue workers in the aftermath of a flooding disaster.

Vibrio is a wound infection that creates a sepsis in the body part exposed.  It is often accompanied by a rash with bloody blisters (hemorrhagic bullae).  This bacteria lives in warm coastal waters and can pose a serious risk after a hurricane.  Vibrio loves warmer waters and is present in large numbers during the months of May through October, making a hurricane a huge vector for transmission.

Mosquito Transmitted Disease

After the hurricane winds are over and the water slowly returns to its proper places, inevitably there will be pools of stagnant water.  This creates an ideal breeding ground for mosquitos.   Water collected in tires, debris, trash cans, buckets, planters, and essentially anything that can hold water allow mosquitoes to lay eggs and reproduce in large numbers.  While those annoying insects pack a stinging bite, more serious issues are possible.  Mosquitoes are known vectors of diseases such as Zika and West Nile.  Protect yourself from mosquito bites with effective sprays, long clothing, and if possible limit exposure.  During the aftermath of a hurricane when electricity is often unavailable, this might be more difficult as an open window is a substitute for air conditioning.  Being vigilant to symptoms is also important to provide appropriate treatment in the event of infection.

Zika is spread primarily through the bite of an Aedes mosquito.  These mosquitoes are known to bite both during the night as well as during the day.  While it poses health issues in mostly the very young, the very old, and those with a compromised immune system, Zika poses a unique health complication for pregnant women, causing birth defects.  Zika may also be transmitted through sexual contact, so transmission can continue well after the waters subside.  There is currently no vaccine available for Zika virus. 

West Nile is also spread primarily through mosquito bite.  A very small percentage of cases have been transmitted from blood infusions, organ transplant, and from mother to baby.  The virus can cause febrile illness, encephalitis (inflammation of the brain), or meningitis (inflammation of the lining of the brain and spinal cord).  Most people infected do not show any symptoms or have mild symptoms.  There is currently no vaccine available for West Nile virus.

Protect Yourself and Your Family

During these difficult times it is important to protect yourself and your family.  Avoiding exposure is the best way to handle the health problems associated with the aftermath of a hurricane.  Be vigilant in keeping things out of your mouth and exposing yourself to potentially contaminated water.  Boil water if you do not have access to clean bottled water.  Dump standing water as soon as possible to reduce mosquito reproduction.  Take as many steps as possible to strengthen the line between you and illness.