Texas Employs Aerial Spraying to Combat West Nile Virus
Published on Aug 16, 2012 by PBSNewsHour
A current epidemic of West Nile virus has claimed the lives of 26 people in the U.S., 10 in Texas alone. In Dallas and the surrounding county, authorities have declared a state of emergency. Jeffrey Brown talks to Baylor College of Medicine's Dr. Kristi Murray about the outbreak and how the state targets infected mosquitoes.
West Nile SymptomsBy Mayo Clinic staff
Most have no symptoms
Most people infected with the West Nile virus have no signs or symptoms.
Mild infection signs and symptoms
About 20 percent of people develop a mild infection called West Nile fever. Common signs and symptoms of West Nile fever include:
- Body aches
- Skin rash (occasionally)
- Swollen lymph glands (occasionally)
- Eye pain (occasionally)
Serious infection signs and symptoms
In less than 1 percent of infected people, the virus causes a serious neurological infection. Such infection may include inflammation of the brain (encephalitis) or of the brain and surrounding membranes (meningoencephalitis). Serious infection may also include infection and inflammation of the membranes surrounding the brain and spinal cord (meningitis), inflammation of the spinal cord (West Nile poliomyelitis) and acute flaccid paralysis — a sudden weakness in your arms, legs or breathing muscles. Signs and symptoms of these diseases include:
- High fever
- Severe headache
- Stiff neck
- Disorientation or confusion
- Stupor or coma
- Tremors or muscle jerking
- Lack of coordination
- Partial paralysis or sudden weakness
Signs and symptoms of West Nile fever usually last a few days, but sign and symptoms of encephalitis or meningitis can linger for weeks, and certain neurological effects, such as muscle weakness, may be permanent.
When to see a doctor
New West Nile Threat: Kidney Disease
Aug. 17, 2012 -- Early in this year's West Nile virus season, the death toll is at 29 and rising. There have been about 700 illnesses reported so far, more than 400 of them serious meningitis or encephalitis.
It's an unusually severe West Nile season -- and now there's new evidence that the virus itself may be unusually dangerous. The new threat: kidney disease years after infection.
Eight in 10 people infected with West Nile virus don't get sick. At least not right away. A new study finds that even in people who never had serious West Nile symptoms, the virus can burrow deep into the body. Years later, this persistent infection often leads to kidney disease that gets worse and worse over time.
As many as 9% of people who have mild or no initial symptoms may have persistent West Nile virus infection, says Baylor University West Nile expert Kristy O. Murray, PhD, DVM.
"Right now, we have seen people continually decline. We have no specific treatment for them to reverse what is happening," Murray says. "Will they eventually need dialysis? It will mean following them even longer to see if some stabilize."
In an NIH-funded study, Murray's team has been keeping track of about 200 people infected with West Nile infection over the last 10 years. About 40% of them now are showing signs of kidney disease and lasting West Nile virus infection.
Patients who survived the terrible symptoms of severe West Nile disease -- sometimes-paralyzing meningitis or encephalitis -- were most likely to suffer persistent infection. These patients also were most likely to have severe kidney damage.
But this is happening even to people who never had symptoms -- people who learned of their West Nile infection only when they were tested when donating blood.
It's an "important" finding, says William Schaffner, MD, professor and chair of preventive medicine at Vanderbilt University and president of the National Foundation for Infectious Diseases.
"This study suggests that West Nile virus infection not only can persist, but that like a termite it slowly and surely gnaws away at kidney function," he says.