Testing performed on the home, mail and local post office of 94-year-old Oxford, Conn., resident Ottilie Lundgren, the nation’s latest victim of inhalation anthrax, has thus far failed to uncover the source of the bacteria.

Investigators are still in the midst of conducting more thorough tests of Lundgren’s home and the few places she frequented in her hometown, Centers for Disease Control and Prevention spokeswoman Rhonda Smith said Friday. More results are expected today.

Lundgren, who died nearly five days after being admitted to Griffin Hospital in Derby, is the fifth person in the United States to die of anthrax in the last seven weeks. Derby and Oxford are about a dozen miles west and northwest of New Haven, respectively.

“I believe this is a remote case,” Connecticut Gov. John G. Rowland told The Associated Press Sunday. “A 94-year-old woman living in Oxford certainly was not a target. It sounds like a case of cross-contamination to me.”

Inhalation anthrax, the most serious form of the disease, can be deadly if not treated immediately, Smith said. Lundgren’s death — and investigators’ inability to locate the source of the anthrax — has led medical and environmental health officials to become even more diligent in searching for potential cases.

In an e-mail to the entire Yale community last week, University Secretary Linda Lorimer, who sits on Yale’s health security task force, said environmental testing conducted on high-volume mail centers around campus has yet to turn up any trace of anthrax spores. Lorimer said she would keep Yale students posted regarding the status of further testing.

But as New Haven Environmental Health Director Paul Kowalski explained, Yale’s testing can only go so far.

When suspicious white powders are found on the Yale campus, Kowalski said, the University cannot immediately undertake a thorough, definitive investigation of the substance.

“Even when an incident occurs and is credible, they have to be directed by the FBI or [state] police to do any kind of investigative work,” Kowalski said. “And even after they get such clearance, the state health lab is the only facility allowed to perform the [definitive] scientific tests.”

Yale can, however, perform a relatively quick type of field test on any questionable substance even without FBI permission, Kowalski said.

He said that officials from Yale’s Department of Occupational and Environmental Health and Safety have been called upon to perform several such tests on substances found around campus, and all have turned up negative for anthrax.

Dr. Stephanie Spangler, a deputy provost and another member of the task force, said that while field tests are often informative as a initial evaluation, they have a non-negligible potential for error.

“There could be false positives and false negatives with this type of test, so we always perform further tests no matter what the results may be,” Spangler said.

Local hospitals are also doing their part to identify potentially misdiagnosed cases of anthrax.

Dr. Mark Russi, who is on the Occupational and Environmental Health faculty at Yale-New Haven Hospital, said that epidemiologists in particular are in the process of reviewing the medical histories of patients who have died since Sept. 11 to check for any symptoms characteristic of anthrax.

Russi also said that the CDC has directed hospitals worldwide — including Yale-New Haven — to be on the lookout for patients who report flu-like symptoms but do not experience runny noses or sore throats.

“The combination of ‘flu-like’ symptoms and the lack of these upper-respiratory illnesses are some of the most distinguishing symptoms of anthrax,” Russi said.

Russi said the hospital is also prepared in case it becomes a target of bioterrorism. Workers in the hospital’s mail room wear gloves when handling all types of parcels, and a decontamination room, adjacent to the emergency room, is fully functional, he said.

University Health Services has also adapted special protocols including a blood count, cultures, and a CT scan of the chest of patients believed to be infected with anthrax, said Dr. Paul Genecin, the director of UHS.

“We certainly are more apt than we have been in the past to consider patients with lower-respiratory infections as possible [anthrax] victims,” Genecin said.

Russi echoed Genecin’s caution.

“Everyone without question should have a lower threshold for reporting anthrax-like symptoms and anthrax-like powder,” Russi said.