“Using air sampling techniques, Dahlgren and co-workers estimated that in one woolen mill, workers were inhaling between 600 and 1300 [anthrax] spores during an eight hour shift with no ill effects.” – R.C. Spencer, 2003
Recent media attention has conveyed concern about possible exposure to anthrax at the CDC. However, unless it is weaponized, anthrax rarely causes respiratory illness. The natural particle size of anthrax spores are too large to get deep into the lungs. By contrast, a relatively small fraction of woolen workers have antibodies to anthrax, a testament to how well our bodies keep the natural spores out.
Anthrax is endemic to the world. Look at this map. Probably at least 1 billion people have been exposed to Anthrax without knowing it. That includes many people in California, England, Germany and France, not just folks in Turkey or sub-Saharan Africa. Anthrax resides in the soil and even in the guts of earthworms. It’s more common in the biosphere than people realize.
Some perspective is in order. First, the CDC, like labs that test for animal pathogens, handles materials that are found outside. Except for smallpox, every pathogen at the CDC is found in the environment. Everything from bubonic plague to anthrax and influenza is out there. So a potential exposure that lab personnel have is not catastrophic. It’s a glitch.
Nobody has contracted anthrax, nor influenza, nor smallpox in these incidents. Lab personnel recognized them and reported them as per procedures.
One can ask how smallpox was left in forgotten containers at the CDC. It’s a reasonable question. But smallpox was common for so many years that saving samples wasn’t remarkable. Essentially, the CDC is the successor to an agency established in 1946. There were sweeps for smallpox after eradication, but things are missed. Someone who stored the sample forgot about it after decades or they retired, or passed away. I have participated in cleaning out and inventorying of storage freezers that develop frost and ice build-up. It’s a big job. Once we found an x-ray plate from a project many years old buried in the ice. A -80 freezer collects ice every time it gets opened. More smallpox might be found tucked away somewhere 50 years from now. It’s a tough virus and some might even be viable.
Second, people at real risk for illness and death are those in the field or working directly with lab animals. I am not aware of a lab microbiology death, although there are illnesses from time to time. (If someone knows of any, please let me know.) Nor am I aware of an illness contracted by the public which came from a laboratory. But field biologists die and so do doctors in the field, as well as animal handlers.
A few years ago a wildlife biologist did a necropsy on a dead mountain lion. He was found dead in his home a week later, dead of pneumonic plague – the disease that killed the lion.
Similarly, a number of doctors have died of Ebola. The latest outbreak in Africa has claimed several medical personnel. A grad student working directly with rhesus macaques died after a bite from a macaque infected with herpes B. About 40 of these infections are known, and 70% were fatal.
It isn’t possible to perfect a laboratory system. We can improve awareness and improve safety, but there are limits and we need to set our priorities. Lab work has some inherent dangers, but fieldwork, clinical work, and handling animals has considerably more. Lab work supports the field, supports application of medicine and veterinary services. We need to be cautious about making rules so rigid and conservative that the mission of laboratories is compromised. Out there in the world beyond the walls of the CDC people are dying. It is the mission of CDC to provide critical services to the public.