"Many analysts rank cultured and genetically engineered biological organisms as the most dangerous of all existing weapons technologies, with the potential for producing more extensive and devastating effects on human populations than even fusion nuclear weapons (Henderson, 1999)." See:http://bioscience.oxfordjournals.org/content/52/7/583.full
In 2001, the New Scientist (4) published an article on a deadly virus created accidentally by an Australian research team trying to genetically engineer a contraceptive vaccine for mice."They spliced a gene for the protein interleukin-4 (IL-4) into the relatively harmless mousepox virus (ectromelia virus) in the hope that IL-4 would boost the immune system to make more antibodies. When the researchers injected this vaccine into mice, all the mice died. In fact, this synthetic virus was so lethal that it also killed half of all the mice that had been vaccinated against mousepox.The work published in the Journal of Virology (http://jvi.asm.org/content/75/3/1205.long) revealed that hte mice used were genetically resistant to the mousepox viruis in the first place. Genetic resistance to mousepox varies among inbred laboratory mice, and depends on natural killer (NK) cells and cytotoxic T-lymphocytes (CTL) responses to viral infection, both of which destroy cells that have been infected with virus so as to clear the body of the virus. The researcher found that expression of IL-4 suppressed both NK and CTL. Genetically resistant mice infected with the IL-4 expressing virus developed symptoms of acute mousepox accompanied by 100% mortality, similar to the disease seen when genetically sensitive mice are infected with the virulent Moscow strain. Strikingly, infection of genetically resistant mice recently immunised against mousepox also resulted in significant mortality. These findings suggest that virus-encoded IL-4 not only suppresses primary antiviral immune responses but also inhibits the expression of immune memory responses. In previous investigations (6,7), the IL-4 gene inserted into another virus used in vaccinations against smallpox, the vaccinia virus, delayed the clearance of the the virus from experimental animals and undermined the animals' anti-viral defence. These results suggest that IL-4 may function similiarly in all viruses in the same family, which also contains the human smallpox virus. These findings raise the spectre of biological warfare. But the far greater danger lies in the unintentional creation of deadly pathogens in the course of apparently innocent genetic engineering experiments. Genetic engineering involves facilitating horizontal transfer and recombination of genetic materials across species barriers, precisely the conditions favouring the creation of new viruses and bacteria that cause diseases.We now know of cases in the laboratory where such viruses have been created. (http://www.twnside.org.sg/title/twr127i.htm)
See: Arturo Casadevall, "The Future of biological warfare", Microbial Biotechnology, Vol.5, Issue 5,584-587, September, 2012.
Jill Bellamy is an internationally recognized expert on biological warfare and defence. She has formerly advised NATO and for the past seventeen years has represented a number of bio-pharmaceutical and government clients working on procurement strategy between NATO MS and Washington DC. Her articles have appeared in the National Review, The Wall Street Journal, The Washington Post, The Sunday Times of London, Le Temps, Le Monde and the Jerusalem Post among other publications. She is a CBRN SME with the U.S. Department of Defence, Chemical, Biological, Radiological and Nuclear Defence Information Analysis Center and CEO of Warfare Technology Analytics, a private consultancy based in the Netherlands. She is an Associate Fellow with the Henry Jackson Society, UK.