In most countries including Singapore, polio is merely a historical memory. Yet the World Health Organisation (WHO) last month declared polio a "public health emergency of international concern".
This came after 68 cases were reported globally in the first four months of the year, up from 24 cases in the same period last year.
The numbers seem tiny, but polio is so contagious that one case is enough to trigger alarm bells.
One case implies that many more carriers, people without symptoms, may be present and spreading the virus. And one carrier can infect hundreds.
Still, the WHO alert was unusual for a world agency known to be loath to make such announcements, especially when specific nations are targeted.
From June 1, any person exiting the three nations currently exporting polio - Pakistan, Syria and Cameroon - must take a dose of the oral polio vaccine and show documented proof for it, even if previously vaccinated.
When India was declared polio-free on March 27, only Afghanistan, Nigeria and Pakistan had never been polio-free. Today, seven nations previously polio-free have been reinfected - Cameroon, Syria, Equatorial Guinea, Ethiopia, Iraq, Israel and Somalia.
Spread by food or drink contaminated with faeces, polio infects mainly children under five years old. Present in the saliva, the virus can also be spread by coughing, sneezing and kissing.
In conditions of overcrowding, poor sanitation, dirty water supply and less than full vaccine coverage in childhood, the virus can spread like wildfire. Going by these factors, Singapore is safe.
Even in most unvaccinated persons, the polio virus causes only a minor illness. But one out of every 200 infections sees the virus attacking the brain and spinal cord, leading to permanent paralysis.
In cases with paralysis, 5 per cent to 10 per cent will die. Those who survive are crippled for life.
The virus is resistant to soap, alcohol and freezing. It survives in sewage for months; in contaminated water, a lot of chlorine is needed to kill it; and at least three shots of the vaccine are needed for effective protection. And it is due to these factors that politics with armed conflict have created ideal conditions in the three polio-exporting nations for polio to break out and circulate widely.
So it is politics that is really driving the current global polio threat.
It can be fairly argued that US foreign policy bears a large part of the blame for Pakistan's polio situation. This is because the Central Intelligence Agency (CIA) used vaccination programmes in Taleban-controlled areas as a cover for its secret operations, including espionage.
The Taleban responded by banning vaccination in north-west Pakistan, which they control. More than 60 vaccinators have been killed in the past two years and many locals believe vaccines are a Western bio-weapon used to render Muslims infertile.
In 2011, a local physician ran a hepatitis vaccination programme for the CIA as cover to get the DNA of children in the Osama bin Laden compound in Pakistan to ascertain if the terrorist leader was likely to be there - and he was.
After a British daily exposed the ruse, the Taleban campaign against vaccinators intensified. And more Pakistanis now distrust vaccination.
Last August, the CIA decided to ban all future use of vaccination programmes as a cover for espionage. But the White House announced this only last month.
The Taleban may have little reason to believe the CIA, but they announced late last month that vaccinations would henceforth be permitted. Taleban fighters have also been ordered to help vaccinators. So there may be hope yet.
Syria has been officially polio-free since 1999, but civil war is now keeping vaccination programmes from reaching its children. More than half of the 1.8 million born since the conflict began in 2010 may not have received even one dose of the polio vaccine, much less all three.
The virus is now spreading in conditions of overcrowding, poor sanitation and dirty water supply.
Last year, the first suspected case in 14 years was reported. By the end of March this year, 27 cases of polio had been reported, all in rebel-held territory.
President Bashar al-Assad is arguably responsible for this as his government has withheld vaccination, clean water and sanitation services from rebel territory.
But his government claims otherwise, a claim supported by the WHO, whose officers are restricted to the capital, Damascus. Until recently, the Assad regime even denied any polio outbreak at all.
Critics have denounced the WHO for being tardy in announcing the epidemic only last October, three months after a paralysed child was first diagnosed in rebel-held Aleppo.
The WHO even asked Turkey not to test samples sent from rebel territory because it had not authorised doctors working in such areas to do so. Only doctors practising in government-controlled areas were authorised.
Then, last October, the US Centres for Disease Control and Prevention confirmed that three such samples were indeed polio. Only then did the WHO announce a polio emergency in Syria.
Acting for the Syrian government also, Unicef likewise took steps to stop manufacturers from selling polio vaccine to Medecins sans Frontieres when the non-profit group tried to buy and supply it to rebel-held areas.
So both the WHO and Unicef have chosen to stand with the Assad administration to maintain access to government-held areas.
Still, since January, a rebel set-up called the Assistance Coordination Unit has organised health-care workers for door-to-door polio vaccination in rebel territory. Hopefully, this makes a dent in what is a dismal situation.
Polio-free for five years until four cases emerged last October, Cameroon has now seen three new cases of polio this year.
Vaccine coverage is poor: 43 per cent of children have not received the three required doses of vaccine while 30 per cent have not had even a single dose.
A big reason is religious. Hard-line Pentecostal churches in this nation that is 70 per cent Christian insist that believers not use modern medicine at all, including vaccines, and rely on Heaven to provide the healing instead.
This situation has now been aggravated by over 100,000 refugees streaming into Cameroon to escape armed conflict in two neighbouring nations, Nigeria and the Central African Republic. Poor living conditions make it very hard for vaccinators to reach refugee children. Thus, polio may explode at any time in this nation.
The WHO first targeted polio eradication for 2000. This goal was then moved repeatedly to 2005, 2008, 2012, 2015 and now to 2018. But with politics at the root of the polio situation in all three source nations, and thus of the global polio threat, stemming it will be very hard and eradicating it by 2018, highly unlikely.
Unfortunately, this ancient scourge looks set to stay.
This article was first published on June 15, 2014. Get a copy of The Straits Times or go to straitstimes.com for more stories.