Patient Zero: International sporting events and bioterrorism.

On 1 February 2016, the World Health Organisation (WHO) declared a public health emergency over the rapid spread of the Zika virus across Latin America. The virus, which was first discovered in Uganda in 1947, is transmitted via the Aedes aegypti mosquito and is thought to have first been brought to Latin America by a traveller attending the 2014 Brazil Soccer World Cup. Since arriving in Brazil, Zika virus infections have spread quickly across the continent, leaving more than 3 million infected as at February 2016. While rarely fatal itself, the virus is believed to cause severe cognitive birth defects in babies born to mothers suffering from Zika fever during their pregnancy, and its particularly rapid spread across the continent has raised concerns among the medical community worldwide.

The Zika virus outbreak and its hypothesised origins at the Brazil Soccer World Cup has provided an almost textbook demonstration of how major international events can serve as fertile breeding grounds for the spread of diseases. The outbreak has also highlighted how such events present an ideal target for extremist groups wishing to deploy biological weapons and capitalise on the spread of such agents across the world. International sporting events in particular are ideal for the dissemination of infectious diseases: people travel from all over the world to attend, are clustered together in confined spaces, such as stadiums and public transport, for extended periods of time, and are more likely to share food, drinks, accommodation and perhaps each other’s beds. These factors create an environment that could easily be targeted by enterprising extremist groups. Biological weapons represent a particularly effective terrorism tool, as an attack need not even result in mass casualties in order to cause widespread panic and fear.

The risk posed by bioterrorism at major international gatherings has historically been taken very seriously by governments hosting such events. Extremist groups whose members are willing to sacrifice themselves for their cause highlight a particularly concerning scenario in which infected members could attend events with the purpose of spreading the disease to as many people as possible.

A number of health and research organisations have previously cited the plague as an ideal example of a potential bioterrorism scenario. The plague, caused by the bacterium Yersinia pestis, infects approximately 1000 individuals a year in the US alone, and is highly infectious. Yersinia pestis is often present in fleas infesting the common marmot and black-footed prairie dog, and plague victims frequently stem from regions were these animals are abundant. Extremist groups could thus readily expose a willing member to the plague, and send such an individual to a major sporting event during the incubation period when symptoms have not yet manifested. The pneumonic strain of the plague in particular is highly infectious, and a carrier could potentially infect thousands in a single day by coughing on people at stadiums and on board crowded public transport.

In May 2000, the US Department of Justice conducted an exercise in Denver, Colorado, on engaging key personnel in the management of a mock biological attack of the plague, named "TOPOFF". TOPOFF demonstrated serious weaknesses in the US public health system that could prevent an effective response to bioterrorism or even severe naturally occurring infectious diseases. Decision-making processes amongst government officials were often slow, the prioritization and distribution of antibiotics lacked control and medical facilities were largely overwhelmed by large numbers of desperate patients. By the end of the simulation, less than a week after the first fictitious attack, more than 4,000 plague infections as well as 950 deaths had been reported in the US, and the disease had ‘spread’ to London and Japan.

In a real-life scenario, the plague initially presents with flu-like symptoms, allowing it to go undetected and misdiagnosed by physicians. The easy misdiagnosis of the disease, combined with the weaknesses demonstrated by the TOPOFF exercise highlight how a planned attack using Yersina pestis could result in hundreds, if not thousands of deaths. Although the bioterrorism ambitions of many extremist groups appear to remain low at this stage, the Zika virus outbreak should serve as a reminder to the public and authorities of the consequences of underestimating biological threats.