Blog | Tuesday, September 11, 2012

QD: News Every Day--West Nile's record outbreak prompts call for 'unrelenting' preventive efforts


A record surge in West Nile infections among people this year has prompted for calls for clinicians to recognize the virus' symptoms, as well as educate patients about how to prevent mosquito bites by using repellants and emptying any standing water that could be used as breeding grounds.

A commentary in Annals of Internal Medicine called for an "unrelenting" effort. "[C]linicians must maintain clinical suspicion of infection under the right circumstances of season and mosquito exposure to arrive at the right diagnosis in a presenting patient."

Meanwhile, the commentary continued, "The public must be constantly prodded, with a balance of sensible precautions and serious awareness of the possibility for severe disease."

West Nile virus infection cases in 2012 in the U.S. have already exceeded that of any other year with 1,590 cases, 65 deaths, and 303 viremic blood donors as of August 28.

Up to 80% of those infected have few or no symptoms, although some experience long-term sequelae such as flaccid paralysis, and deaths have resulted from encephalitis and meningoencephalitis.

A few environmental conditions could be contributing to the outbreak. West Nile virus has become endemic in North America because of the combination of birds and mosquitoes. The infection may be prevalent in avian populations, and the species of mosquitos that feed on birds and people breed in conditions such as sewers, storm drains and catch basins that are part of residential infrastructure.

Furthermore, the commentator said, this year's droughts actually create more of these breeding grounds by drying up otherwise flowing water supplies, creating more stagnant water. And heat waves speed up both the reproductive rate of mosquitoes and how fast viruses develop within them.

"Reduction of mosquitoes requires an integrated pest management approach, and we must come to grips with the sometimes controversial issue of pesticide application to kill adult mosquitoes, when benefit outweighs risk, and objectively determine efficacy under various conditions," the author wrote. "And for the long-term, perhaps modifications in the way we create our own environment will prove an important part of reducing the impact of the disease."