As of September of this year, there have been more than 2,600 new cases of West Nile virus in the USA, including 118 deaths, which were reported to the CDC in Atlanta, Georgia.
While most people have no symptoms of West Nile, some have life-threatening brain inflammation, which leaves survivors with long-term disabilities including paralysis and fatigue. Researchers are investigating the hypothesis that even mild infections might leave another lasting problem, kidney disease. The scientists published their findings in the journal PLoS ONE.
It could be a worrisome development, states Kristy Murray, an epidemiologist at the Baylor College of Medicine in Houston, Texas, who hasn’t yet confirmed that kidney disease persists long after a West Nile infection. She hopes to find a link soon, as she has moved her research to a new biosecurity level 3 laboratory near the Texas Children’s Hospital.
The claim needs to be investigated and if Murray’s findings are true, it could be a major problem having to deal with all of these people with mild infections. In another study, Murray collected urine samples from 25 West Nile survivors and found that five had viral RNA in their urine, well after they had been infected, suggesting that the virus might have established itself in the kidneys.
In order to examine whether the virus actually harms the kidneys over time, the researchers looked for indicators of long-term kidney disease in urine samples of 139 people. In July she reported that 40% of that group showed the signs of long-term kidney disease.
Murray’s latest study didn’t include a control group, and a CDC study of some West Nile survivors in Colorado found no evidence of viral RNA in the subjects’ urine. Multiple labs need to find the same results from the same blinded samples in order to confirm this hypothesis.
Murray claims that the single-stranded fragments of RNA are easily broken apart by enzymes in the fluid, and freezing as well as thawing samples doesn’t help matters. However, her own subjects traveled for just one hour to the University of Texas Medical Branch in Galveston.
At her new lab, Murray plans on using a four-year grant from the NIH to recruit 440 people, half of whom had West Nile, in order to finally confirm her findings.
Reference: “Prevalence of Chronic Kidney Disease and Progression of Disease Over Time among Patients Enrolled in the Houston West Nile Virus Cohort” by Melissa S. Nolan, Amber S. Podoll, Anne M. Hause, Katherine M. Akers, Kevin W. Finkel and Kristy O. Murra, 6 July 2012, PLoS ONE.
DOI: 10.1371/journal.pone.0040374