Wednesday, January 23, 2008

 

Travellers spread diseases over long distances

Businessworld
Nayan Chanda

The american airlines’ non-stop flight that takes passengers from Delhi to Chicago is a great boon to travellers. But the 16-hour journey inside an airline cabin also provides ample time for a carrier of contagious diseases, such as tuberculosis (TB), to infect his fellow passengers. Welcome on board and please fasten your seatbelts: this is high-speed globalisation.

Earlier this month, the US Center for Disease Control (CDC) launched a nationwide search to find some 44 passengers who arrived in the country on American Airlines flight 293 from Delhi. They needed to be contacted urgently to be tested for a multi-drug resistant TB infection that they may have picked up from a fellow passenger. A Nepali resident of California was diagnosed with a rare, drug-resistant form of the disease while in India, but it was only after she had returned to the US and checked into a hospital that the alarm bells began to sound, prompting the CDC to track down passengers who might have been infected while on board, and who may now be in the process of spreading the disease further.

It is frightening, but not new. A similar drama unfolded last June, when an American TB patient, Andrew Speaker, was found to have boarded international flights despite being told that his strain of the disease was highly contagious. Fortunately, Speaker had not infected any of his fellow travellers, but we still do not know if we will be so lucky this time round. Nor does one know if the latest traveller infected anybody in India. We do know, however, that with air travel booming, one has to be prepared for many more such emergencies.


If Speaker and the more recent Nepali patient have brought home one lesson, it is that hyper-connected globalisation has reached a point where the health and well-being of many around the world can hang by the thread of one individual’s actions in a faraway place. International bodies such as the World Health Organization (WHO) and government health services the world over now have to prepare for emergencies triggered by ignorant or inadvertent action by any of us.

Had these patients been infected with a pathogen as contagious as SARS (severe acute respiratory syndrome) or worse, the consequences could have been catastrophic. With tens of thousands of commercial flights carrying some 800 million international passengers around the world each year, viruses have acquired a velocity that they never had before. Past pandemics such as the bubonic plague ‘Black Death’ and the Spanish flu spread slowly — limited by the speed of a horse-drawn carriage or a steam boat — and killed tens of millions before they died out over time.

Such catastrophes prompted human society to initiate new and unprecedented public health programmes. It was during the time of Black Death in the 14th century that the city of Venice forbade vessels from docking at a port until they had spent 40 (qarantina in Italian) days in the water, that is until the infected ones had perished. The word ‘quarantine’ born then has become a standard health policy tool, but, in the meantime, viruses have evolved and found speedier carriers in the jet plane.

The speed and frequency of today’s travel has placed individuals at the centrestage and produced myriad challenges to controlling the spread of infectious diseases. It is useful to recall that it was the action of one man, ironically, a professor of medicine from the Chinese city of Guangzhou, that enabled the lethal SARS virus to cross the Chinese border and go global. Liu Jianlun, who had treated SARS patients in his hospital and knew they were suffering from a highly contagious disease, nevertheless decided to travel to Hong Kong to attend his nephew’s wedding. Several guests staying on the same floor at the Metropole Hotel subsequently became infected and left for Hanoi, Toronto and Singapore. By the time the pandemic was finally stopped, it had taken over 800 lives in 32 countries around the world.


With the growing speed of travel and burgeoning number of travellers, millions can be inadvertently placed at risk by the careless actions of the Dr Lius and Andrew Speakers of the world. Government agencies have to be more vigilant than ever to avoid health emergencies and cooperate more fully with WHO. But it is time that we also recognise our individual responsibility and capacity to wreak havoc as citizens of an intimately connected world.



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