The forty-six-year-old man had been sick a week and a half when his wife drove him from his home near Beaumont to UTMB in early August 2002. What started as fatigue and occasional diarrhea had suddenly turned into high fever, shaking chills, a headache, and worsening lethargy. Doctors-worried that the immunosuppressive drugs he'd been taking since receiving a kidney transplant two months before had made him vulnerable to runaway infection-ordered him hospitalized. Despite treatment, he continued to suffer memory loss, muscle weakness, and other neurological symptoms. Four days after admission, he was almost completely paralyzed, and he soon slipped into a near-coma. Seven weeks later, he died.
Although his doctors didn't know it then, the patient was one of Texas' first victims of West Nile virus. He contracted the disease when a mosquito bit him, possibly while he sat on the front porch of his home, and his weakened immune system was no match for the virus. Most people easily fight off West Nile, but in some-mainly those over fifty or, like the East Texas patient, with impaired immunity-it may cause severe encephalitis and death.
No therapy or vaccine yet works against West Nile. But although medical science could do little for this patient, he did much for medical science. Drawing on clinical observations, his blood and cerebrospinal fluid samples, and magnetic resonance scans taken during his fifty-four-day battle with West Nile, UTMB researchers produced a vivid profile of the disease's progression.
"This helps to put together a puzzle about what happens in some of the manifestations of West Nile infection, and it contributes to our understanding that people who are immunosuppressed are at greater risk of severe illness if they get infected with the virus," says UTMB's Robert Tesh, the senior author of an article on the case that appeared in the online edition of Clinical Infectious Diseases.
The article also reported the group's success in isolating West Nile virus from the patient's cerebrospinal fluid, a first in North America, and noted that blood the patient received at UTMB, taken from a Houston donor by the Gulf Coast Regional Blood Bank, also contained West Nile virus. The first reports of West Nile transmission via blood transfusions or organ donations appeared just after the man received his transfusion; blood banks did not have a test to exclude West Nile-infected blood until May 2003.
Genetic analysis revealed, however, that the strain of the virus in the donated blood was different from the virus that killed the patient. According to Tesh, who made the first discovery of West Nile in Texas in summer 2002 when he isolated it from the brain of a blue jay, mutations have already split the virus into two different Texas varieties: one from the state's eastern tip near Beaumont, and the other from Harris County west to El Paso.
"The genetic sequence of the virus from the transfusion is like the viruses found in Houston and Austin, while the virus that was present in his brain when he died is like that found in East Texas," Tesh says. "I think that suggests that's where he was infected, not from the blood transfusion."