The Effect of Hurricanes on Pathogenic Diseases.

Author:Maness, Lisa R.
Position::SPECIAL REPORT - Report


2017 was a year of extreme hurricane activity in Texas and Puerto Rico, with lasting effects that will not quickly be forgotten. Extensive flooding and damaging winds are usually the first concerns that come to mind when people think about hurricanes such as Harvey and Maria. Few people immediately think about pathogenic diseases when discussing major tropical weather systems. News reports can remind people to use caution during power outages and to not eat food that is preserved in suboptimal refrigeration temperatures. The public can be reminded to drink bottled water instead of using tap water after hurricanes. Interestingly, secondary effects from hurricane destruction do play a subtle role and are likely undetected and undiagnosed in many cases. Several scientific studies indicate that after hurricanes, there is an increase in cases of some pathogenic diseases. In addition, statistical evidence indicates increases in emergency department and physician office visits by patients reporting symptoms of a variety of conditions. Other evidence shows that the risk itself is greater for contracting certain illnesses following hurricane damage due to a greater presence of organisms in the environment during and after hurricanes in comparison with before the storm.

Potential Pathogens in the Environment After Hurricanes

Failed levees lead to damaging flooding following major hurricanes, leading to breaches in municipal water systems. This occurrence can cause mixing of sewage water and drinking water or cause increases in runoff from farmland, causing animal waste to leach into drinking water (Renaissance Computing Institute, 2012). After Hurricane Sandy, farmlands became flooded and municipal waste treatment plants were under water, which affected the coastal regions of North Carolina in 1999. A variety of animal farms flooded, resulting in hogs, turkeys, and chickens drowning and having to be burned in order to prevent the spread of disease.

Millions of gallons of manure were released into rivers, thereby contaminating water supplies. Over 300 private wells tested positive for coliform bacteria. One study indicated increases in illnesses from Toxoplasma gondii and adenovirus following Hurricane Sandy in severely affected areas of North Carolina (Setzer & Domino, 2004). Although T. gondii is carried primarily by cats, intermediate hosts include livestock, suggesting that this organism was spread to humans due to flooding of livestock farms.

Studies that determine the presence of pathogens in environmental waters after hurricanes can indicate what potential risks there are to people cleaning up or working in the aftermath of hurricanes (Sinigalliano et al., 2007). After Hurricanes Katrina and Rita in August and September of 2005, Vibrio cholerae, V. vulnificus, and, less frequently, V. parahaemolyticus were found in Lake Pontchartrain in Louisiana. Various Legionella species were also present in this lake after these hurricanes, and in a rare number of samples L. pneumophila, the cause of Legionnaires' disease, was present. Just after floodwaters receded, levels of these potential pathogens were higher than several months after the hurricanes. Cryptosporidium and Giardia cysts were found in canal waters in New Orleans, Louisiana, deriving from runoff around the canals. Epidemiological studies were not correlated with these findings, but the presence of these bacterial and parasitic species indicates increased health risks associated with these organisms after floods caused by hurricanes--especially for survivors who are exposed to environmental sources.

Leptospira Illnesses From Environment Causes

Another environmental organism of concern for hurricane survivors is Leptospira. The Centers for Disease Control and Prevention (CDC) states that leptospirosis can occur following exposure to water or soil that has been contaminated with infected animal urine or other body fluids, or by directly touching urine or body fluids from an infected animal (CDC, 2018). Leptospirosis was blamed for several deaths in Puerto Rico following Hurricane Maria, which is not the first time Leptospira bacteria have been reported in victims of hurricanes ("Leptospirosis cases reported in Puerto Rico," 2017). In 1996, Hurricane Hortense hit Puerto Rico and 142 dengue-negative patients were tested for Leptospira (Sanders et al., 1999). In this group, 4 of 72 prehurricane samples and 17 of 70 post-hurricane samples were confirmed to be positive for Leptospira, which is a large increase in cases when comparing numbers before and after the storm.

Hurricane Mitch severely affected Honduras in 1998 and a study of 68 people with leptospirosis symptoms were tested for the disease (Naranjo et al., 2008). They found that 24 of the 68 who were tested had positive results for a variety of Leptospira species. They reported that 80.8% of those tested reported the presence of rodents in or around their homes, while 86.7% reported having contact with stagnant water, and 55.8% reported having contact with pets. Any or all of these risk factors likely contributed to the large number of cases of leptospirosis after Hurricane Mitch.

Skin Diseases Secondary to Hurricanes

Various people who were exposed to the devastation of Hurricane Katrina exhibited debilitating skin conditions and gastroenteritis soon after. CDC...

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