It swept across 214 countries worldwide and killed more than 18,000 people. The 2009 H1N1 influenza outbreak, dubbed “swine flu,” put the entire world on alert. The outbreak was declared to be a global pandemic until August 2010. But threat of deadly disease outbreaks didn’t stop — or start — there.
In 2003, SARS (Severe Acute Respiratory Syndrome) crossed the world, originating in Asia and reaching Canada in less than a day. In 2012, a new virus emerged in the Middle East and entered the global arena soon after. Aptly named Middle-East Respiratory Syndrome (MERS -CoV) it continues to spread today, albeit slowly, with almost 1,000 people having been infected to date, including 356 dead as of 5 February 2015.
In 2014, the disease on everyone’s mind was Ebola. The Ebola virus has infected almost 23,000 people across nine countries to date, with more than 9,000 deaths as of 10 February 2015. However, despite the high number of infections, the spread of Ebola remains technically an outbreak, not a pandemic, because it hasn’t spread globally.
“It will only be over when the last person with Ebola is either dead or recovered without infecting other people,” stated Peter Piot, who co-discovered the virus in the 1970s, at the World Economic Forum meeting in Davos last month. But he warned that risks from such outbreaks were far from over, saying: “There will be other Ebola outbreaks and there will be other epidemics, not least influenza.”
But is the world ready?
Hundreds of infectious diseases continue to plague the planet in both urban and rural locations, from ones spread by insects, such as Chikungunya, which is currently sweeping through the Americas, to those spread by water, such as cholera, or human contact, such as Ebola. “Infectious organisms can travel in humans, food and insects … you can’t stop disease from crossing borders,” says David Heymann, head of the Centre for Global Health Security at think tank Chatham House.
One initiative in place to identify those posing a more global risk is the WHO-led Global Alert and Response Network (GOARN). “[It’s] a series of laboratories, national public health institutions and groups like Medecins Sans Frontiers who report regularly when an outbreak occurs,” says Heymann. The goal is the rapid identification, confirmation and response to outbreaks of international importance.
“The ones with most risk are airborne,” says Heymann. The greatest pandemic to date was the Spanish flu which spread in 1918 and is estimated to have infected a third of the world’s population at the time and caused approximately 50 million deaths. More recently, the hardest hitting outbreaks were the SARS coronavirus in 2003, followed by H1N1 influenza virus in 2009. All of which were respiratory infections with the potential to spread far and fast.
“With flu I’m quite sure there will be another pandemic,” says Wendy Barclay, chair in influenza virology at Imperial College, London. Barclay researches the origin of pandemics and why some viruses cross species to jump from animals into humans. In the case of H1N1, the virus was a re-assortment of bird flu and pig influenza viruses, resulting in a new form infectious to humans and with no immunity among those at risk.
“If it’s a new one, there’s no pre-existing antibodies to hold that off … and you may then pass it on to someone else,” says Barclay.
Experts agree that future outbreaks and potential pandemics may occur, but the lessons learned from previous ones should enable a faster response. The key is to identify the virus, estimate its threat and its potential to spread across a population as quickly as possible to then put a pandemic preparedness plan into action.
“Flu is difficult to control in terms of an outbreak,” says Barclay, as the virus has the ability to spread before people show symptoms, meaning measures such as airport screening are ineffective. The converse is true for viruses such as Ebola and particularly SARS, where people are only contagious once showing symptoms of the disease. “We were able to contain SARS,” says Barclay, because patients could only transmit the virus days after symptoms had begun. If a patient was admitted to hospital soon after their symptoms appeared, there was a lesser risk that they had already infected others in their wake.
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