He points out that anyone involved in lab design or facility management should embrace new technologies, but should also remember that the ultimate reason behind the technology goes back to the nature of the microbes being studied. In laboratories there is a clear link between the engineering of technology and the agents involved.

"Good lab design can definitely help to facilitate the containment process, but it can never take the place of scientists trained in the proper procedural steps to contain microbes," adds Dr. Kiley, who learned this firsthand when he began his career in 1978 at the Centers for Disease Control studying the hemorrhagic fever viruses.

Such deadly viruses continue to make headlines, including newly discovered strains of the West Nile virus in the U.S. and abroad. In addition, recent attacks using laboratory-produced Anthrax as a weapon have heightened concerns of both bio-safety and bio-security. Several recently passed laws address these concerns, including the USA Patriot Act of 2001, which has provisions on how laboratories can work with "select agents and toxins," and the Bio-terrorism Preparedness Act of 2001, which is designed to control the use and distribution of so called "select agents," defined as biological agents thought to pose a bio-terrorism threat to the United States.

"It is crucial that we continue to find scientists willing to work with these organisms and that the work continue in a safe and effective manner," says Dr. Kiley, who explains that these organisms can often have devastating effects on agriculture, as well as animals and humans. As a key example he points to the trickle down effect felt by Midwest corn farmers who lost $1.5 billion in sales to Taiwan when the Taiwanese pork industry was crippled by foot and mouth disease several years ago.

Bio-Safety Levels

With more than 24 million people working in some phase of agriculture within the U.S., it is one of the largest employers within the country. Sales and exporting of food and fiber products account for more than 13 percent of the U.S. gross national product and each year alone, livestock exports typically total from $6 to $10 billion.

To help protect these valuable resources the U.S. Public Health Service established a series of bio-safety levels (BSL) designed to help reduce the risk of laboratory infection or the release of microbes to the environment. The levels define a set of parameters for work practices, containment devices, and construction technology for use with specific microbes. There are levels 1 through 4, with higher levels pertaining to more pathogenic microbes, which require stricter containment procedures. (See box, Bio-Safety Levels)

Another level, known as "BSL-3 Agriculture," has added requirements to protect American agriculture, both animals and crops, from exposure to pathogens and potential infection. This is the strictest level pertaining to agriculture. Some of the criteria taken into consideration to categorize agents into a particular level include the agent's pathogenicity or ability to cause disease, its biological stability, the concentration of the organism, and whether or not there is an effective vaccine or therapy available.

"Most high-containment labs usually deal with viruses," says Dr. Kiley who calls viruses the ultimate parasites because they have no energy source of their own and are absolutely dependent on the cellular mechanisms to replicate.  "In fact, many of the current lab safety and design practices are actually based on the nature of viruses," he notes.

Agent Types

Viruses contain only one type of nucleic acid (either DNA or RNA, but not both) and then a protein shell coating to protect the viral genetic information. A virus has no energy source. Instead, the virus particle inserts its nucleic acid or genetic information into the cell and uses the cell processes to make viral proteins that are responsible for manufacturing new particles.

"The contact of an agent with a host is not necessarily enough to cause a viral infection," says Dr. Kiley. "Typically you need parameters such as the right number of organisms, the right hosts, the right portal of entry, and the right tissues to come in contact with the correct agents and these parameters are different for each agent."

The West Nile virus is an example of a unique transmission characteristic. West Nile requires a reservoir, in this case birds, which are the amplifying hosts. People and animals can become infected incidentally by the bite of a mosquito, but apparently do not make enough viruses to cause transmission to other animals. Horses, for example, can't pass along the agent because they don't build up sufficient amounts in the blood for the mosquito to transmit to the next host.

"Researchers and scientists who deal with agents such as viruses have helped to eradicate numerous animal diseases within the U.S. such as foot and mouth disease and cattle tick fever," says Dr. Kiley. "They have also been instrumental in learning more about emerging animal diseases such as Lyme disease, E. coli, and the West Nile virus."

Safety Procedures and Design

Accident prevention is a concern for every lab, but it should be top priority for high-containment labs that deal with agents classified at bio-safety levels 3 and 4 since workers are at greater risk from accidents such as needle sticks, injury by sharp blade or glass, spills, sprays, and even animal bites and scratches.

At these levels, following proper procedural safeguards and implementing safe work practices are the foundation for lab safety. Key examples include restricting access to lab and work areas, conducting experiments in class 3 cabinets or isolation suits with their own air supply, and following the proper procedures for waste disposal and decontamination.

"While good design can help to reduce accidents, especially those associated with environmental factors, design is not a substitute for good laboratory practices," says Dr. Kiley, who points to the staff at CDC's Building 9 (the first bio-safety level 4 laboratory that required isolation suits) as a prime example of safe work standards. The staff worked for more than 10 years with no safety or cross contamination problems even though they were using multiple agents and multiple animals.

By Amy Cammell