New West Nile Threat: Kidney Disease
Even Without Symptoms, West Nile Virus May Lead to Lasting Infection of the Kidneys
There's no vaccine against West Nile virus. Vaccines do exist for similar viruses spread by mosquitoes, making a West Nile vaccine at least technically possible. Tests of blood and cerebrospinal fluid (CSF) can detect acute infection. Murray says her lab has developed a test to detect virus in the urine.
There's no treatment for West Nile virus infection. Murray says that in animal studies, existing antiviral drugs appear to make the infection worse, not better.
Anyone who has had West Nile in the past should get annual checkups of kidney function, Schaffner and Murray suggest.
The CDC said it would not comment on the work of Murray, a former agency employee, for this story.
Murray and colleagues reported their findings in the online journal PLoS. Since they submitted their results, Murray says her team has confirmed persistent human West Nile infection by directly seeing live virus in urine with an electron microscope, a more sensitive test than she used in the original study.
2012 West Nile Season Beginning, Not Ending
With about 700 reported cases in 43 U.S. states as of the second week of August, the 2012 West Nile season is off to a fast start.
Case counts and deaths have not yet peaked, says infectious disease expert Jorge Parada, MD, MPH, professor of medicine at New Orleans' Loyola University and medical spokesman for the National Pest Management Association.
"The game is not over yet," Parada says. "We will see cases continue to rise over the foreseeable future."
That's no surprise to Dallas, Texas, where a West Nile health emergency has been declared and officials have resorted to aerial spraying to kill off mosquitoes. Parada says that although spraying does kill many adult mosquitoes, whether it's effective must be determined on a local case-by-case basis.
More than 80% of cases reported so far have been in Texas, Louisiana, Mississippi, Oklahoma, South Dakota, and California. But the virus is present everywhere there are mosquitoes, heat, and a little bit of water.
Other than protecting oneself against mosquito bites -- wearing effective insect repellent and/or wearing long sleeves and long pants despite hot weather -- Parada says people should look to their homes.
"One thing relatively simple that most just don't do is take a walk around their homes," he says. "If there is standing water -- there often is, in a pot or birdbath or old tire -- remember that mosquitoes can breed in tiny amounts of water so long as it remains there for a few days. And clean your gutters: There is standing water up there. Don't make your house a breeding ground for mosquitoes that carry West Nile."