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After tap water containing the brain-eating amoeba Naegleria fowleri claimed the life of a four-year-old boy in St. Bernard Parish, Louisiana, state epidemiologist Raoult Ratard posits that the amoeba may have populated the water supply as a result of post-Katrina conditions in the area. Ratard admits that his theory is “just an idea,” but one that does raise important questions about the state of local infrastructure since the region experienced devastating flooding some eight years ago.
Photo (cc) USACE on Flickr
Following the death of four-year-old Drake Smith Jr., CDC tests at four points in the St. Bernard water system found high levels of the Naegleria fowleri amoeba. It is exceptionally difficult for the amoeba to enter one’s brain—one has to sharply inhale the contaminated water through the nose—but in the rare instances where a human is infected, the ameoba is almost always fatal.
But what the CDC tests found in addition to the worryingly high presence of a brain-eating amoeba was also unusually low levels of chlorine. This was of particular note as maintaining a certain level of chlorine in water supplies is what typically prevents contamination such as this from happening. Which is where Ratard’s theory comes in.
St. Bernard Parish sits directly adjacent to the Lower 9th Ward of New Orleans, and as with the Lower 9th Ward and several other areas, St. Bernard experienced devastating levels of flooding both from the storm and from a levee breach at the Industrial Canal in the Lower 9th Ward. Homes were left submerged under as much as 15 feet of floodwater, and all aspects of infrastructure—including water pipes—were significantly damaged. While St. Bernard has arguably recovered faster then the neighboring Lower 9th Ward, it still has a markedly lower population than it did pre-storm; the most recent census suggests 35,000 of the parish’s 67,000 residents have returned.
This population decrease means a number of vacant and demolished properties, which according to Ratard means “lots of parts of the system where water is sitting there under the sun and not circulating.” Sitting in the hot Louisiana sun could have had two effects on the water supply, according to Ratard. Firstly, the hot water provides conditions in which the amoeba can rapidly multiply, and secondly Ratard claims that studies show the summer heat can destroy chlorine added to the water supply.
It’s unlikely, or even impossible, that Ratard will ever be able to prove his theory. Speaking to Discovery, Dawn Wesson, an epidemiologist at Tulane University explained the concern that “My understanding is that this amoeba is pretty common in freshwater throughout the United States. As a scientist, I wouldn’t necessarily support Katrina as a causation there.”
Disasters are, however, often the cause of disease outbreaks. With infrastructure that has remained in place and largely unchanged in the wake of an event as devastating as Hurricane Katrina, perhaps this latest disease outbreak might cause a reexamination of something so basic and vital as the water supply.