New study suggests West Nile may cause kidney problems
Reported December 08, 2009
While fear over West Nile virus has largely subsided in Canada, a new study says some people previously infected could be at risk for long-term effects.
The study, to be published Jan. 1 in the Journal of Infectious Diseases and is available online, says the virus can survive in a person’s kidneys for many years. Several of the patients studied who continued to carry the virus suffered a kidney failure years later.
The study recommends anyone previously infected with the West Nile virus should have their kidneys checked regularly, even if they don’t have any chronic symptoms.
“People should be checking with their physicians to see about having their kidney function examined,” said Dr. Kristy Murray, the lead researcher for the study from the University of Texas School of Public Health in Houston. “It’s not until the person is pretty far progressed in terms of damage to the kidneys before they start showing signs of kidney disease.”
Prior to this study, it was believed that humans only remained infected for the first few days of illness. Many people had chronic symptoms after contracting West Nile virus, including fatigue, weakness and memory loss, but this is the first proof that the virus can actually survive in the human body.
The study began with roughly 100 patients with severe West Nile infections, who were tested for seven years after their initial infection. More than half continued to have infection-related symptoms, and five eventually died of kidney failure.
The deaths led Murray and her team to look more closely at the kidneys of 25 patients from the original group. Five of these patients tested positive for the virus, and four of those experienced chronic symptoms from West Nile virus, including weakness, fatigue and memory loss. One of these patients also experienced kidney failure.
Because the test was relatively small, it will not have an immediate impact on public health policy, said Dr. Susan Roberecki, medical lead with the environmental health branch of Manitoba Health.
“I would watch to see if it could be replicated, and then obviously it may have some implications for clinical practice,” said Roberecki. She also said that the strain tested is slightly different than the one that has affected most Canadians.
Murray says she is working with the Centers for Disease Control and Prevention in the United States to develop a way to make her tests for West Nile virus more accessible. She said her ultimate goal is to develop a treatment.
“We’ve now identified this and now can work toward developing a treatment option for these individuals,” said Murray.
In Canada, there have been nearly 4,800 reported human cases of West Nile virus since 2002, but only eight confirmed or probable cases in 2009, according to the Public Health Agency of Canada. Officials say they will be reviewing Murray’s study.
Source : Canwest News Service
