CASE IN SMALL TOWN COMPOUNDS A PUZZLE FOR EPIDEMIOLOGISTS
20 Nov 2002
Source: New York Times, November 22, 2001.
Case in a Small Town Compounds a Puzzle for Epidemiologists
By LAWRENCE K. ALTMAN
Epidemiologists investigating the anthrax death yesterday of Otillie W. Lundgren, 94, from Oxford, Conn., are confronting a mystery as baffling as the case of a Bronx woman, Kathy T. Nguyen, who died on Oct. 31 leaving no clue to the source of her infection.
The puzzle is how Mrs. Lundgren, a woman in her 90's who lived alone, walked with a cane and had limited contact with the world outside her home could have come down with inhalation anthrax. Anthrax has been rare in Connecticut; since 1950, the state has reported just one case, and that was the skin form involving a male mill worker in Glenville in 1968.
Even though Mrs. Lundgren seemed an unlikely anthrax patient, her doctors at Griffin Hospital in Derby, Conn., started acting on recommendations from the Centers for Disease Control and Prevention for multiple drug treatment as soon as they had a hint that she had the infection on Saturday, a day after she was admitted to the hospital.
The doctors told her she might have anthrax and asked about her activities. She told them she had noted nothing unusual about her mail, did not garden, and could shed no light on the possible source, said Dr. Kenneth Dobuler, chief of medicine at Griffin Hospital. The hospital did not notify the state's Public Health Department about her case until Monday, so epidemiologists were unable to interview her before she died.
Now, as epidemiologists talk to her family and friends to learn about her activities and who she encountered over the six weeks before she became ill, they will try to fit what facts they glean into the accepted wisdom about the bacterial infection.
In contending with the first known deliberate spreading of anthrax spores in history, the authorities have found that the accepted wisdom of medical texts has been challenged on several fronts.
As they examine the puzzling cases of Mrs. Lundgren and Ms. Nguyen, federal health officials wonder:
What is the smallest number of spores that can cause anthrax?
Does it take fewer spores to infect an older person than a younger one?
How often have anthrax cases, particularly in older people, gone undetected because they were diagnosed as pneumonia?
How often can anthrax spores be found in areas where cases have not been reported for many years?
Mrs. Lundgren's strain of anthrax matches that of the other 18 confirmed cases, said Tom Skinner, a C.D.C. spokesman. It will be later this week before scientists learn whether spores were present in her home, which investigators tested Tuesday. The medical detectives are also looking for evidence of contamination in her mail.
Anthrax spores can survive for decades and they are commonly found on ranches where it has killed cattle. But scientists have not conducted surveys to determine how often anthrax spores can be found in the ground, homes or office buildings in Connecticut or elsewhere in the country.
It may take a smaller number of spores to produce inhalation anthrax in a 90-year-old person than in a much younger person if their immune system had been weakened by age or if the debris collected in years of breathing had damaged the cells that whisk particles away from the lungs, said Dr. Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases.
An average of 8,000 to 10,000 spores are needed to cause death from inhalation anthrax in animals.
But no one knows the minimal number it takes to cause infection in a human, said Dr. James M. Hughes, who oversees C.D.C.'s investigation into the anthrax outbreak as head of its infectious diseases center.
Dr. Jeffrey P. Koplan, director of the disease centers, said yesterday that it was unlikely that Mrs. Lundgren was infected naturally, but that epidemiologists would have to keep an open mind and explore all possibilities. Among the considerations is the possibility that her infection came from contamination of some medication she took.
Inhalation anthrax has been rare in this country, with only 18 cases reported since 1950. Dr. Koplan said it was unlikely that many cases of inhalation anthrax were missed in the past, but he added "it's conceivable that our heightened surveillance" in recent weeks has detected cases that might previously have gone undetected.
Connecticut is one of the states involved in a network that C.D.C. created about six years ago to investigate unexplained deaths, and that program has not turned up any cases of anthrax, Dr. Hughes said.
Doctors in Derby were astonished when Mrs. Lundgren -- whom they had admitted to the hospital out of concern that she had become slightly dehydrated by what appeared to be a mild respiratory infection -- became the country's fifth death from anthrax since early October.
When a relative drove Mrs. Lundgren to the hospital late Friday morning, she supplied her own medical history. She had a mild cough, was a little short of breath, and had a temperature of about 102.3 degrees Fahrenheit, Dr. Dobuler said. A number of tests, including a white blood count (that can rise with a bacterial infection) and a chest X-ray, were normal.
Because they suspected she had a viral infection, doctors did not prescribe antibiotics until Saturday when all four cultures of her blood grew microbes that resembled Bacillus anthracis. Hospital microbiologists performed more tests on Sunday and determined that it was the anthrax bacillus, not one known as B. cereus that can be a contaminant from the skin and with which B. anthracis can be confused.
Mrs. Lundgren's condition remained stable Saturday and Sunday, and she talked readily as her condition remained stable. But during that time the doctors did not ask her about exposure to animals and other epidemiologic factors related to anthrax.
On Monday, as Mrs. Lundgren's condition deteriorated rapidly, her chest X-ray became abnormal, but it did not show the characteristic widening of the mediastinum, the space between the lungs that is typically expanded by swollen lymph nodes when they are infected with anthrax, Dr. Dobuler said. The hospital notified the health department, which performed additional tests to identify the microbe as B. anthracis.
Final confirmation came early Wednesday morning from a polymerase chain reaction test performed on samples sent to C.D.C. in Atlanta. The test can theoretically detect a single microbe in a sample.
C.D.C. has sent a team of 17 epidemiologists, environmental health specialists and other scientists to Connecticut to investigate Mrs. Lundgren's case.
"Do we have any insight where her anthrax came from?" Dr. Fauci said. "No."
He continued: "But the possible light at the end of the tunnel is that unlike Kathy Nguyen, about whose movements we know very little, Mrs. Lundgren was housebound and when she did go out, she always went with one or two friends. So under those circumstances it might be much easier for law enforcement authorities and epidemiologists to really track every place she has been over recent weeks. If there is a clue there, hopefully they will find it."