* Polio virus often comes back in areas of poverty, unrest
* Refugee, nomadic populations hard to reach with vaccines
* Experts say focussed campaigns are crucial
By Kate Kelland, Health and Science Correspondent
LONDON, Oct 29 (Reuters) - With the world tantalisingly close to wiping out polio, conflict in Syria has allowed the crippling disease to take hold again, putting at risk the rest of the region as well as plans for global eradication.
War, unrest and poverty have often hindered the long fight against polio, but experts say these obstacles can be overcome, even in Syria where the highly contagious virus has taken advantage of a fall in vaccination rates due to the fighting.
The key, according to Siddharth Chatterjee, a polio specialist who has fought back the disease many times in conflict zones, is to banish politics from public health and focus on saving children's lives. Polio can spread rapidly among those under the age of five.
"This is about the neutral, impartial, independent nature of healthcare," said Chatterjee, who is head of strategic partnerships at the International Federation of Red Cross and Red Crescent Societies.
"You need to be talking to all the bad guys, all the good guys, all the religious leaders, all the people who have any form of influence on the community. It's about ensuring you delineate politics from the child."
The polio outbreak in Syria, confirmed on Tuesday by the World Health Organisation (WHO), is depressingly similar to previous resurgences in countries such as Sudan and Colombia, where the once eliminated virus exploited opportunities offered by conflict and poverty to find its way back in.
Polio spreads easily from person to person. The WHO's ominous warning is that as long as any child remains infected, children everywhere are at risk.
Caused by a virus transmitted via contaminated food and water, it can spread rapidly among children, especially in the kind of unsanitary conditions endured by displaced people in Syria or in crowded refugee camps in neighbouring countries.
But repeated and comprehensive immunisation programmes can and do beat the disease completely, as shown by the dramatic success of the worldwide campaign to eradicate polio which has cut the global number of cases by 99.9 percent since 1985, from 350,000 then to 223 last year.
Health groups said in April that a $5.5 billion vaccination and monitoring plan could entirely rid the world of polio by 2018, but recent outbreaks in Pakistan and Somalia, as well as this latest reappearance in Syria, threaten that timetable.
Syria had not seen polio since 1999, according to the WHO, but its 2-1/2-year-old conflict, which began with popular protests against President Bashar al-Assad before degenerating into civil war, has brought poverty, violence and displacement to many millions of people there.
And polio was not far behind. Syria's health ministry said on Oct. 19 that 22 children in the country's north eastern Deir al-Zor province had become paralysed with polio-like symptoms. The WHO's Tunis laboratory has now isolated the polio virus in samples taken from 10 victims.
In Somalia, which had not had a case of polio for almost six years, the virus has also come back, exploiting conflict and political unrest in areas that cannot be reached by government vaccination campaigns.
"It's very hard to reach nomadic populations ... even in normal circumstances," said John Rhodes, a vaccines and immunology expert and the author of a book entitled The End of Plagues.
"So when there is a conflict and certain areas become no-go zones for vaccination teams, it becomes very difficult indeed."
Chatterjee, a former Indian special forces officer who survived polio as a child, urged global public health officials and donors to the fight against polio not to be defeatist, despite the disease's re-emergence.
"Even in a place like Syria, where we can see things have become very internecine, it is not impossible," he told Reuters. "We've done it Darfur, we've done it in other parts of Sudan. Conflict certainly brings an additional challenge, but it's not impossible to overcome."
To succeed, he said, engaging with health workers and community volunteers on all sides of any political, ethnic or religious divide is crucial.
"Ultimately you need to appeal to a person who may be a terrorist by others' estimations, and recognise that he is likely also to be a father, a brother, or have nieces or nephews who may be under five and need health interventions," he said.
Bruce Aylward, the WHO's assistant director general for polio emergencies, agreed that while a setback, the virus' re-emergence in Syria was likely to be overcome by a determined and well-equipped eradication campaign.
"These problems are always there in one form or another, in one place or another," he said. "Too often there is a sense 'we will wait til the war ends, we will deal with it later' (but this outbreak) forces you today to go in and deal with the difficulties and challenges of reaching them."