Local bioterrorism as a potential global threat

by Angela Herring

According to a new com­puter mod­eling research study from North­eastern Uni­ver­sity net­work sci­en­tist Alessandro Vespig­nani, when it comes to bioter­rorist attacks, “dis­eases have no bor­ders.” Thus, an out­break of smallpox intended to harm a local pop­u­la­tion would ulti­mately affect the entire planet.

Vespig­nani, the Stern­berg Family Dis­tin­guished Pro­fessor of PhysicsHealth Sci­ences, and Com­puter and Infor­ma­tion Sci­ence at North­eastern, and his team mod­eled the spread of a hypo­thet­ical smallpox virus across the globe and found that even with the most con­ser­v­a­tive esti­mates, a small ini­tial attack in the city of London would likely spread to two or four coun­tries before the first cases were even diag­nosed, Vespig­nani said. The results were reported in a paper pub­lished Wednesday in the journal Sci­en­tific Reports.

Pre­vious research from other groups have claimed opti­mistic con­trol out­comes by imple­menting effec­tive con­tain­ment poli­cies and suf­fi­cient vac­cine stock­piles. While these con­di­tions may be real­istic for many western coun­tries, Vespig­nani said, the same is not true across all nations. “These papers con­sid­ered the local dimen­sion of a poten­tial attack,” Vespig­nani explained. He added that we are no longer lim­ited by local bound­aries. The modern trans­porta­tion system would allow unknow­ingly infected indi­vid­uals to travel across the globe well before any local con­tain­ment policy was con­sid­ered, he said.

The team rec­og­nized that some mem­bers of the global pop­u­la­tion might be immune to the pathogen if they received the smallpox vac­cine before it was erad­i­cated in 1977. But while accounting for immu­nity brings down the number of indi­vidual cases, the same number of coun­tries would be affected regard­less, according to the model.

Vespig­nani noted that the doc­trine of “mutu­ally assured destruc­tion” should deter even ter­rorist orga­ni­za­tions, which don’t want to bring dev­as­ta­tion to their own people. Nonethe­less, he warned, the world must still be pre­pared for such events. His team’s mod­eling exer­cise is a step in that direction.

Addi­tion­ally, with exper­i­ments on increas­ingly infec­tious pathogens like H5N1 cur­rently taking place in research lab­o­ra­to­ries, the model is also rel­e­vant in the case of an acci­dental out­break. The con­di­tions are slightly dif­ferent in these sce­narios, as diag­nosis would likely happen much sooner, but at least in the case of an acci­dental smallpox out­break, the problem reaches the inter­na­tional scale just as readily as with an intended outbreak.

Vespignani’s team is cur­rently adapting its model to look specif­i­cally at H5N1.

Originally published on news@Northeastern on July 17, 2013

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