At this point last year, Dallas County had already recorded a handful of West Nile deaths, a figure that would ramp up to 19 in the following weeks and months as the number of infections skyrocketed.
But the West Nile outbreak of 2012, which resulted in a record 286 death nationwide, is less of an anomaly than a sign of things to come, according to a pair of studies, one by the CDC, one by Dallas County health officials, and an op-ed published Tuesday by the Journal of the American Medical Association.
"Every once in a while, you will have the right conditions to have it build up in the mosquito and bird populations, and spill over to humans," Stephen M. Ostroff, a former deputy director of CDC's National Center for Infectious Diseases, writes in an editorial.
That's not, by and large, how it's been handled by the public health community, which he argues has grown complacent about West Nile as memories the virus' sudden emergence in New York City in 1999 and its seeming peak in 2003, when it killed 264 people, have faded. Research funding has dropped from $35 million in the early 2000s to less than $10 million by 2012. Monitoring efforts fell off. The general public stopped seeing it as the major threat that it is.
The CDC report (paywall) backs up these conclusions, foreseeing "unpredictable local and regional outbreaks" and that the disease "will remain a formidable clinical and public health problem for years to come."
The Dallas County report gives a hint of just how ill-prepared public health officials were for the 2012 outbreak. Citing a fragmented mosquito surveillance system and a containment plan that relied too heavily on clinical reports of the disease, which typically come three to four weeks after the initial infection, the authors say the response was too little, too late to head off the worst damage.
Had the county begun its intensive ground- and aerial-spraying campaign on July 7, roughly a month earlier, and continued it for two consecutive weeks, it "could have prevented an estimated 110 additional WNND cases and an additional 12 deaths," they write.
The authors don't dwell much on the aerial spraying. It was effective, they say, and safe. The incidents of hospital visits for lower respiratory symptoms stayed steady in the six weeks before and seven days after the aerial spraying. They note rather blandly, it "generated publicity over safety concerns."
Still, they argue that a hefty $1.6-million price tag for two coatings of pesticide pales in comparison to the more than $8 million in hospital and related costs incurred by West Nile victims.
So, what's to come in Dallas County? Much of it health officials have already discussed: Earlier testing of mosquito pools; more aggressive treatment of stagnant water, such as that found in abandoned backyard pools; a more sophisticated West Nile tracking system. In general, though, they seem to be heeding Orstoff's call to take West Nile very seriously.