Jason Henry/New York Times/Redux/eyevine
About 200 people are thought to have been killed by Hurricanes Harvey and Irma in the Caribbean and southern US. But many more will feel knock-on health effects in the coming weeks and years: from infections and toxic chemicals released by the floodwaters, from stress, and even as a result of working to rebuild shattered cities.
The immediate death toll has fortunately fallen far short of the 1800 people who died when Hurricane Katrina struck New Orleans in 2005, partly because of better emergency preparation. But thousands are still at risk.
So far, most health reports have come from the US, the wealthiest country affected. “As with Katrina, we’re seeing an increase in diarrhoeal and respiratory illnesses in evacuation centres,” says Peter Hotez at Baylor College of Medicine in Houston, Texas, where Hurricane Harvey hit on 25 August. Common respiratory viruses spread faster and cause worse disease among crowded, stressed people.
Floodwater is one of the main hazards. Sewage washed into floodwater is laden with E. coli and other microbes that can cause diarrhoea, including the cholera-causing bacterium Vibrio cholera in places such as Haiti where it is present. People who wore contact lenses in the floodwater are also at risk of corneal infection.
Floodwater also spreads skin infections, such as that caused by waterborne bacterium Vibrio vulnificus, which can worsen to sepsis, a severe blood infection. “That was a killer after Katrina,” says Hotez.
Chronic conditions can worsen among people who have been displaced from their homes, as those with diabetes, heart disease, psychiatric disorders or HIV are separated from medications and the refrigeration they may need. After other disasters, between 30 and 40 per cent of all displaced people have developed depression or post-traumatic stress disorder.
The whole affected region hosts mosquito-borne diseases such as dengue. While some mosquito breeding sites are washed away by floods, many more are created as water pools in debris. That led to a doubling in cases of West Nile virus the year after Katrina. “Mosquito numbers are already increasing,” says Hotez.
Other health risks include hantaviruses carried by urban rats, which can thrive amid debris and spoiled food. Even anthrax spores are known to be mobilised from soils by flooding after a drought.
The biggest threat may be from the downed electricity grid: millions will be without power for weeks in Florida, months in Puerto Rico. The main health risks are loss of food refrigeration, emergency communications and air conditioning, especially in Florida, where elderly people caught in the heat have already died.
Over the coming months and years, cleaning up may cause more injuries and deaths than the storm did. People can be injured by unsafe structures, and as floodwaters fall, mould proliferates within 48 hours, which can provoke asthma attacks.
The least-recognised risk will be the pressure to rebuild. After Katrina, workplace health and safety was routinely ignored.
A fifth of workers received no protective gear, and only half were told about risks from asbestos, mould or unsafe structures on job sites.
Three-quarters reported illness on the job, but with no medical assistance on offer only a quarter of workers – and only 8 per cent of the undocumented migrants – sought treatment.
Things are unlikely to be better in Texas and Florida, which have no workplace safety laws for government employees such as emergency responders. Texas is the only US state that doesn’t require employers to compensate workers for injuries: a construction worker dies there every three days. Recovery workers could keep dying long after the winds do.
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