Efforts genetically to engineer pathogens runs into evolutionary trouble

Last month the Washington Post ran an article about the National Biodefenses Analysis and Countermeasures Center (NBACC) planned for construction at Fort Detrick, Maryland. Among the center’s priorities, as inadvertently released on the internet, are to “assess the nature of nontraditional, novel, and nonendemic induction of disease from potential biological threat agents” and “characterize classical, emerging, and genetically engineered pathogens for their biological threat agent potential.” In other words, NBACC plans to look at biologicial threats that do not exist yet and against which human immune systems have not yet developed. “Nature is constantly creating new pathogens, testing out new agents. It seems rather inevitable that if someone is bent on destruction, it should become possible to synthesise entire genes and make chimeras you can mix and match,” says Steven Block of Stanford University.

Synthetic genomics is the next frontier in biological weaponry. Developing new strains has a number of potential advantages for the determined terrorist. For one, many of the known deadly pathogens such as plague and smallpox are highly contained in secure government research labs, primarily in the United States and Russia. Those that are more widely available, either through clandestine purchase or through natural synthesis such as anthrax, are not deadly enough to create widespread terror. The ideal terrorist pathogen would be moderately safe enough to handle and transport, easily dispersed, and virulent enough to infect large numbers of people — but not so strong that it killed off those initially exposed before they had the chance to infect others. According to scientists in the industry, overcoming this “one-kill cycle” is not easy.

Not that scientists have not tried. In 2001 biologists in Australia added a mammal gene to a mousepox virus to make the virus produce a chemical called interleukin-4. Their interest had nothing to do with terrorism, but they soon discovered that their altered mousepox killed even vaccinated mice. The worry, of course, was that a similar alteration to smallpox could manage to overcome the human smallpox vaccine. Follow-up experiments, however, showed that the altered mousepox strain did not spread well because the mice died too quickly. Traditional diseases have gone through millions of iterations as they have evolved, perfecting themselves over time to reproduce by killing slowly and efficiently. After all, a smallpox gene wants to make as many copies of itself as it can — quickly killing off the first exposed host is an evolutionary dead end.

-read more in Wendy Orent’s The Peninsula analysis ;