Spread by infected mosquitoes, West Nile virus was first detected in the United States in 1999. Since then, approximately 25,000 human cases have been reported, causing more than 1,000 deaths. Many more have become infected without showing symptoms. Previous animal studies raised the possibility that patients may still be infected with the virus several years after recovering from their initial illness.
Prior to this latest research, however, humans were thought to remain infected with West Nile virus only for the first few days of illness. The study, led by Kristy Murray, DVM, PhD at the University of Texas School of Public Health in Houston, demonstrates that not all individuals clear the virus from their system within the first few days—and that it can remain in the kidneys for years, potentially leading to kidney failure.
Dr. Murray and her colleagues followed more than 100 patients in Houston with severe initial West Nile virus infections for seven years. Individuals were evaluated and blood samples collected every six months. More than half continued to have infection-related symptoms years after their initial illness, although symptoms began to plateau around two years after infection. The deaths of five participants due to kidney failure led researchers to consider whether the kidney could be a preferred replication site for the virus.
To test this hypothesis, Dr. Murray and her team collected urine samples from 25 patients from their original cohort and tested them for presence of West Nile virus. In this group, five patients (20 percent) tested positive for the virus. Viral RNA could be detected in the urine for at least six years following infection. Four of the five patients who tested positive for virus also experienced chronic symptoms. Of these five, one patient developed kidney failure. These results show that West Nile virus is capable of long term persistence in patients, particularly when chronic symptoms are present.
In an accompanying editorial, Ernest Gould, PhD, of the Centre for Ecology and Hydrology in Oxford, England, points out that this study raises the additional concern that West Nile virus and other flaviviruses may be transmitted to mosquitoes by apparently healthy humans or animals. This possibility has the potential to start epidemics in new regions of the world.
According to Dr. Murray, patients who have been infected with West Nile virus should “have their kidneys monitored by their physician for any evidence of disease and be aware that persistent infection of the kidneys can happen.” Dr. Murray also reminds the public to take proper precautions to protect themselves from mosquito bites during transmission seasons, typically the summer and fall, to avoid infection.
More research is needed to “understand the underlying mechanisms related to the shedding of virus particles in urine, whether shedding of the virus is constant or intermittent, and whether or not this represents true infection resulting in kidney disease,” the investigators say. They continue to evaluate all study participants, particularly in regard to kidney function. In addition, they are focusing on developing treatment options for those who remain infected with the virus.
Fast FactsIndividuals who have had severe infections with West Nile virus may harbor the virus in their kidneys for many years.
This study suggests that individuals infected with West Nile virus should have their kidneys monitored for disease and be aware that disease persistence can occur.
Founded in 1904, The Journal of Infectious Diseases is the premier publication in the Western Hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune mechanisms. Articles in JID include research results from microbiology, immunology, epidemiology, and related disciplines. It is published under the auspices of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing more than 9,000 physicians and scientists who specialize in infectious diseases.
John Heys | EurekAlert!
Navigational view of the brain thanks to powerful X-rays
18.10.2017 | Georgia Institute of Technology
Separating methane and CO2 will become more efficient
18.10.2017 | KU Leuven
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Materials Sciences
18.10.2017 | Physics and Astronomy
18.10.2017 | Physics and Astronomy