Recent acts of bioterrorism using anthrax have highlighted the use of biological agents as weapons of mass destruction. Speculative discussions on the possible impact of the use of viruses such as smallpox as a biological weapon have taken place from time to time over the years and have been escalated recently. Furthermore, the possible genetic manipulation of highly variable viruses such as influenza and their deliberate release are a source of great concern since an effective vaccine cannot be stored.
The establishment and development of intelligence epidemiological services at CDC beginning in the 1950's were part of our first partial response to concerns about the potential use of biological agents as a source of terror. Alternative preventative measures such as vaccination, vaccine dilution and antibiotic and vaccine stockpiling or responsive strategies such as the isolation (quarantine) of individuals, buildings, populations and regions, the rapid control of mass transportation systems, and the systematic surveillance of food and water supply remain present issues for which mathematical modeling is extremely relevant.
Surveillance approaches have typically been based on the assumption that the problem begins with a single outbreak and a single source. There were further advances, for example, when Rvachev and collaborators in the 1970's and 80's looked at the role of transportation systems on the geographic spread of the flu and pondered the potential use of transportation systems as a mechanism for the deliberate release of biological agents. Today, the likelihood of multiple and simultaneous releases poses a challenge not only to those in charge of the surveillance and control of unexpected outbreaks but to our national security.
The impact of deliberate releases of biological agents (Hoof and Mouth, Mediterranean Fruit Flies, Citrus rust, etc.) on agricultural systems and/or our food supply needs to be addressed and evaluated. For example, Hoof and Mouth disease was most likely introduced simultaneously in Britain at multiple sites via the cattle food supply. Hence, it was difficult to contain despite Britain's effective post-detection response (stamping-out). The costs associated with its containment have been estimated to be over $10 billion.
The use of agents like Anthrax highlights the need to look at models for the dispersion of pathogens in buildings (models of air flow in buildings) and in water systems (e.g. dispersion while flowing through pipes) as well as the potential use of communication systems (mail) on their spread. The need to model detectors (reaction diffusion equations) and to develop innovative methods of detection is important. The possible contamination of our water supply raises multiple challenges since detection, evaluation and response must be effective and immediate.
The current advances in genomics already provide useful tools that could be used to fight bioterrorism. For example, DNA sequencing is routinely used to characterize pathogens' strain phylogenies, a critical step in the identification of potential sources of supply of an agent, and consequently on the possible identification of networks of terror.
The deliberate release of biological agents is likely to be carried out by sophisticated and highly indoctrinated groups of individuals. The dynamics of these groups (how they are formed and maintained) as well as those associated with the spread of fanatic ideologies (a serious disease) need to be understood. The survival and reproduction of bioterrorist cells depends on the mechanisms behind these dynamics. A serious effort to understand and model the dynamics of these groups is therefore critically important.
DIMACS Working Groups: These are small, interdisciplinary groups which get together to investigate a subject of common interest. We aim to establish collaborations and usually schedule followup meetings as appropriate.