Mysterious Death After Gardening

June 13, 2008 — -- When a man in England opened some bags of old gardening mulch last spring, a dense cloud of dust billowed up around him.

The 47-year-old welder did not know that the cloud he and his partner saw wasn't dust but spores of a common fungus. Nor did he know that his day of gardening would lead to his untimely death days later.

Doctors in the local intensive-care unit raced to diagnose him as his lungs slowly shut down. Now, a year after his death, specialists at the local Buckinghamshire Hospital have published their explanation for this unusual case in the journal Lancet.

The doctors say an extremely rare infection — once in a medical career rare — from the aspergillus spore caused his deadly infection. However, top minds in the United States have a different solution to this mystery: from a centuries-old "farmer's lung" reaction to a rare genetic disease diagnosis.

Invisible Weakness, Visible Spores

"We only managed to find out what really was going on with him from the story from his partner," says Dr. David Waghorn, of the department of microbiology of Wycombe Hospital, Buckinghamshire, U.K.

"She remembered him being almost enveloped in a whole cloud of dust," Waghorn says. One of the many tests the doctors gave to the gardener was a spit test, and after his death, his spit grew a colony of aspergillus spores.

These spores float around in the air in small amounts, and most people breathe them in with no problem at all, Waghorn says. But some people with weakened immune systems such as leukemia patients, or lung disease patients, can develop a serious infection from them.

Waghorn and his colleagues knew aspergillus spores particularly love to grow in warm, nutrient-rich compost and mulch, and the partner reported the mulch the gardener was using had been sitting around for a long time collecting spores.

"It had been merrily growing away in the mulch," Waghorn says. When he opened the bag, "he couldn't do very much else, unfortunately, but breathe them in."

The doctors knew that the gardener smoked 10 cigarettes a day and wondered whether his welding career had exposed his lungs to other dangers. If these two factors weakened his lungs' defenses, the cloud of spores could have sent him to the hospital with severe aspergillosis.

For Waghorn and his colleagues, the spore dust was a puzzle solved but rarely seen. However, an American expert in aspergillosis and lung disease believes the U.K. doctors missed a key point in their case.

Rare Genetic Disease?

For Dr. Brahm Segal, chief of the Division of Infectious Diseases at Roswell Park Cancer Institute in Buffalo, N.Y., smoking, welding and spit are not enough proof for a diagnosis of aspergillosis.

"The gold standard would have been an autopsy," says Segal, who also said he would have been satisfied if the doctors had taken a tissue sample and tested for the fungus. "He may or he may not have it."

Segal, who is affiliated with the Infectious Diseases Society of America, says he sees cases of aspergillosis quite frequently in his hospital. In fact, he warns against gardening for patients receiving chemotherapy for leukemia or people on potent drugs to suppress their immune systems before transplant operations. People who smoke, on the other hand, aren't at the same risk.

"This is in the category of people's Bic lighters spontaneously exploding," says Segal, who adds that it's "irresponsible" to warn the public against gardening because of the U.K. welder's case.

However, Segal has his own idea about what happened. "The opposite side of the coin is that this patient may very well have a very rare inherited disorder called CGD," or chronic granulomatous disease.

Segal says with the lung disease CGD, an exposure to a cloud of aspergillus spores could send someone to the emergency room. Yet, an infectious disease expert in California has a more common explanation: a reaction similar to "farmer's lung."

Another Diagnosis: An Unusual Allergy

"I think they got this a bit wrong," says Dr. David Stevens, chief of the Division of the Infectious diseases at Santa Clara Valley Medical Center in San Jose, Calif.

Stevens doesn't think it's an inherited disorder that weakens the lungs, nor does he think the gardener contracted the acute infection the way the British doctors propose. However, Stevens does blame the aspergillus spores.

Stevens, who writes medical textbook entries on the subject of aspergillosis, says he recently has cut out the paragraphs describing "extrinsic allergic alveolitis … an unusual form of aspergillus lung disease" for space concerns.

"We are right now inhaling aspergillus spores," Stevens says. "And many of us, many people, do have an allergy to aspergillus, and if they get hit with this massive amount of spores, the problem just cascades."

Stevens guesses by the chest scans, blood tests and spit test result from the gardener that he may have had an unknown allergy.

"It's less common than it used to be, because the setting that you used to see it was in a farmer who would go someplace where hay was wintering, and the farmer goes in there and starts shoveling it or rotate it," Stevens says. Massive amounts of spores are more likely to grow in barns or silos. "But with less than 5 percent of the population farming, it's not really an issue now," he says.

Whatever the gardener had, all the doctors agreed that, aside from industrial composting or farming, careful backyard gardening won't put most people at risk.

"I would not want to give the impression that this sort of thing is a danger to an everyday gardener," Waghorn says. "What happened with this poor gentlemen is incredibly rare."