Symptoms of Severe West Nile Virus Persist For Over a Year in Some Patients, New Academy Study Finds

NEW YORK CITY, Aug. 12???Most people infected with severe West Nile virus in New York City are still not fully recovered within one year of leaving the hospital, according to new research conducted by The New York Academy of Medicine and the New York City Department of Health and Mental Hygiene. The study, in the August issue of the journal Emerging Infectious Diseases, is the first to follow West Nile patients for more than a year to assess their long-term physical and cognitive health status and their daily functioning ability.

???Our study showed that many people with severe West Nile virus infection suffered lingering and debilitating symptoms well after they left the hospital,??? said senior author Denis Nash, Ph.D., M.P.H., an Investigator in the Academy Center for Urban Epidemiologic Studies. ???West Nile virus infection appears to cause longer-term health problems than was previously appreciated.???

Symptoms last longer than expected in severe cases of West Nile virus.

Patients 65 and older were significantly less likely than younger patients to recover from the severe form of the mosquito-borne disease, which can cause encephalitis and meningitis and can require hospitalization. Coupled with evidence from prior studies that seniors are most susceptible to severe West Nile, the new research further underscores the need for infection-prevention efforts focused on elderly populations, researchers said.

The study followed 42 New York City residents between the ages of 16 and 90 years who were hospitalized with severe West Nile infection in 1999, when the virus first emerged in the Western Hemisphere. (Just under one percent of West Nile patients develop severe neurological infection requiring hospitalization, while most others experience mild symptoms or no symptoms at all). The patients were interviewed by phone at six, 12 and 18 months after falling ill. At the 12 month interview, nearly two-thirds of patients, or 63 percent, were still suffering muscle weakness, frequent headache, difficulty concentrating and other persistent problems. Only 37 percent had fully recovered, most of them younger than age 65.

After 18 months, more than 40 percent of severely infected patients continued to report difficulty walking, muscle weakness, fatigue and insomnia, while 30 percent still suffered from memory loss, confusion, depression and irritability and continued to need assistance with activities of daily living. While these conditions may be partly attributable to the normal toll of aging, it remains an important finding that seniors are worst-impacted and require a prolonged recuperation and rehabilitation period, Nash said.

West Nile virus has become a national public health concern as it has rapidly spread westward across the United States since 1999, causing 160 deaths and thousands of hospitalizations in 2003 alone. People living in areas where West Nile activity has been detected in birds, mosquitoes or humans should take common sense precautions to avoid exposure to mosquitoes and reduce mosquito breeding sites on their property. In New York City, pesticides are being sprayed from trucks and aerially to control mosquito populations and West Nile virus. (View the spraying schedule).

About the study:

To assess physical health status, patients suffering from severe West Nile virus were asked to describe the current and pre-infection extent of their difficulty walking, fatigue, headache, insomnia, joint pain, muscle pain and weakness, seizures and stiff neck. Cognitive health was measured according to patients??? description of their confusion, depression, irritability, lightheadedness, loss of concentration and loss of memory before and since infection. Functional health was measured according to patients??? self-described ability to perform heavy chores, laundry and light housekeeping, manage medications, manage money, prepare meals, go shopping, use the telephone and use transportation both before and since infection.

Emerging Infectious Diseases is a peer-reviewed journal published by the U.S. Centers for Disease Control and Prevention (CDC). The New York Academy of Medicine is a non-profit institution founded in 1847 that is dedicated to enhancing the health of the public through research, education and advocacy, with a particular focus on disadvantaged urban populations. Visit the Academy online.

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Posted on August 12, 2004

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Contact:
Andrew J. Martin
Director of Communications
The New York Academy of Medicine
1216 Fifth Avenue
New York, New York 10029
212-822-7285
amartin@nyam.org

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