Hurricanes

How Hurricanes Cause Disease Outbreaks

Long after a storm has passed, disease can dog an impacted community.

Direct Relief staff deliver medical aid to Gulf Coast Health Center in Port Arthur, Texas in response to Hurricane Harvey. Access to vital medicine is often jeopardized after a hurricane. (Photo by Bimarian Films for Direct Relief)
Direct Relief staff deliver medical aid to Gulf Coast Health Center in Port Arthur, Texas in response to Hurricane Harvey. Access to vital medicine is often jeopardized after a hurricane. (Photo by Bimarian Films for Direct Relief)

It’s hurricane season. At Direct Relief, that means it’s time to worry about disease prevention.

When a storm hits, all eyes are on its destructive path. Homes are torn apart, whole communities are displaced, and worst of all, the death toll rises. In the hours and days that follow, attention turns to the search for survivors and the treatment of deadly injuries. And then the world’s eyes turn elsewhere again.

But disasters can cause threats to public health that turn into their own calamities – and continue for months or even years after the storm has passed. Robert Kim-Farley is a professor of Epidemiology and Community Health Services at the UCLA Fielding School of Public Health. He explained that conditions in the wake of a flooding disaster, when sanitation is compromised, displaced people are crowded together, and there’s an abundance of standing water, allow disease to flourish.

Fighting a disease outbreak is especially challenging when resources are stretched to the breaking point and access to even basic care is interrupted for months on end.

These issues are especially problematic in regions where basic infrastructure isn’t strong and serious illnesses are already endemic. But according to Nathaniel Hupert, a professor of Healthcare Policy and Research at Weill Cornell Medical College and co-director of the Cornell Institute for Disease and Disaster Preparedness, some post-disaster health problems – infectious or not – can show up pretty much anywhere.

Hupert said that, in the wake of a disaster, infectious diseases crop up in one of two ways: either they’re already present in a community, or they’re opportunistic infections that respond particularly well to disaster conditions.

And where other health problems are concerned, whether behavioral health or disrupted treatments for existing conditions, everyone is at risk.

Endemic diseases

“Complex disasters exacerbate existing endemic and also emerging diseases because they typically interfere with response activities that have been implemented to defend the public’s health,” Hupert said. In other words, if it’s already present in a community, it’s more likely to blossom in disaster conditions.

Disasters impart a one-two punch that’s especially dangerous for the spread of disease: They crowd people closely together in shelters or camps, and they interrupt the continuum of care that’s needed to keep illness at bay. That means that tuberculosis, meningitis, even measles – and other diseases that may require isolation, medications, and vaccinations – are more likely to gain a foothold in communities that are already vulnerable.

That’s especially true in the developing world, Kim-Farley said: “People already are nutritionally compromised, they have weaker immune systems, and you have a ripe situation for a measles outbreak” when vaccination rates are already low.

Crowded conditions and a lack of medical care also allow respiratory illnesses to spread like wildfire. That may not sound so terrible – after all, we’re talking about the common cold and its ilk. But acute respiratory infections, especially among people who are already lacking nutritious food or clean water, can be a major cause of death in displaced populations. That’s especially true for children under five.

Predatory infections

In the second category, Hupert said, are “predatory infectious diseases that pop up exactly where you don’t want them to. Once they gain entree into a precarious situation, they have an opportunity to flourish.”

Cholera is probably the best-known example, made possible by poor sanitation – in particular, when a source of drinking water is contaminated by disease-harboring human waste. Regions without as much existing infrastructure are particularly at risk, but hurricane conditions – when flooding forces people to walk in water contaminated with sewage – increase the risk for everyone.

Basically, any disease that can be transmitted through contaminated water – a list that includes typhoid, hepatitis A and E, and even plain old E. coli – has the potential to thrive in hurricane conditions.

So do mosquito-borne viruses. Flooding inevitably means a lot of standing, unsanitary water – the perfect breeding grounds for mosquitoes. Malaria outbreaks in particular have repeatedly occurred after floods.

Hupert stressed that even opportunistic infections have to spring from a nearby source. A region that’s successfully eradicated cholera is unlikely to see it just because a disaster strikes – although there are deadly exceptions.

Famously, in 2010, a cholera epidemic broke out in Haiti in the wake of a major earthquake. The outbreak shocked the health community: Cholera had been eradicated from Haiti decades earlier. The new source? United Nations peacekeepers, who’d been dispatched from Nepal to aid in the earthquake response – bringing with them a strain of cholera to which Haitians had no immunity. The country has struggled with the disease ever since.

But where mosquito-borne illness is concerned, both Hupert and Kim-Farley cautioned that the definition of “nearby” is beginning to change. Previously, diseases like dengue fever were concentrated within a narrow range of latitudes close to the equator, where it was warm enough for them to thrive year-round. Now, disease-carrying mosquitoes occupy a range that’s increasingly spreading into the southern United States, already prone to hurricanes and flooding.

Non-communicable diseases

Less studied – but increasingly important as non-communicable diseases become more common – is the role that natural disasters play in exacerbating existing conditions. Vital medicines are frequently damaged or left behind during a natural disaster, and replacements sometimes can’t be obtained. Even primary-care services are disrupted or unavailable. “If [people] don’t have access to those medicines, that could be life-threatening,” Kim-Farley said.

There’s some good news: According to Hupert, the picture is changing. As extreme weather events become more common, health systems are becoming more aware of who’s vulnerable – and what can be done to protect them.

Behavioral health

Better understood is the close relationship between natural disasters and behavioral health concerns, which can be caused or exacerbated by extreme conditions. People dealing with the immediate aftermath of a disaster deal with extraordinary stress that can give way to longer-term conditions, including depression, anxiety, and post-traumatic stress disorder.

And they deal with long-term stressors that continue long after the initial danger of the storm has passed. Researchers have found that not having a source of income or access to insurance in the wake of a disaster can contribute to existing behavioral health concerns.

Plans in place

These are complex issues. But there are some concrete solutions. According to Hupert, one of the most important factors in preventing post-disaster diseases is “nothing exotic, just basic primary care.”

A well-equipped primary care provider, Hupert explained, can make a huge difference for a vulnerable population. That person can “do simple things like making sure that kids aren’t losing too much fluid from diarrhea, making sure that lungs sound clear, and being able to respond with fairly simple interventions, like electrolytes and antibiotics.”

If the provider is appropriately trained, they can even manage pre-existing conditions and screen people for behavioral health issues. It’s not a cure-all, but it’s an invaluable first line of defense.

In addition, Kim-Farley said there’s simply no substitute for good planning. Those essential supplies – including rehydration salts, antibiotics, and medicines for non-communicable diseases – “need to be pre-positioned so that there will be access for people in a disaster situation.”

The good news? There’s more and more awareness around the issue. “Public health officials are running scared all the time about disaster-prone areas,” Kim-Farley said.

Experts agree that as the climate crisis grows worse, extreme weather will become more common. “We’re living in a world in which these things are not as rare as they may have been,” Hupert said. Increasingly, health systems, governments, and aid groups will need to focus on providing continuous care and reliable access to medications – long before a disaster actually hits.

Related Stories

The Latest