Taliban's hostility towards anti-polio drive deepened after it emerged that the CIA had used a vaccination campaign to spy on Osama bin Laden's compound before he was killed.
Pakistan's war on polio in peril through violence, fear and suspicion
ISLAMABAD // Bushra Bibi, a Pakistani health worker, spent eight years trekking to remote villages, carefully dripping polio vaccine into toddlers' mouths to protect them from the crippling disease.
But now the 35-year-old is too scared to go to work, after masked men on motorbikes gunned down nine of her colleagues in a string of attacks last week.
"I have seen so much pain in the eyes of mothers whose children have been infected," she said. "So I have never seen this as just a job. It is my passion. But I also have a family to look after ... Things have never been this bad."
After the deaths, the United Nations put its workers on lockdown. Immunisations by the Pakistani government continued in parts of the country but the violence raised fresh questions about the stability of the South Asian nation.
Pakistan's Taliban insurgency considers the anti-polio drive to be just another western plot against Muslims, and has long threatened action against anyone taking part in it.
The militant group's hostility deepened after it emerged that the CIA, with the help of a Pakistani doctor, had used a vaccination campaign to spy on Osama bin Laden's compound before he was killed by US special forces in a Pakistan town last year.
Critics say the attacks on the health workers were a prime example of the government's failure to formulate a decisive policy on tackling militancy, despite pressure from the United States, the source of billions of dollars in aid.
For years, the authorities were aware that Taliban commanders had broadcast claims that the vaccination drive was a plot to sterilise Muslims.
"Ever since they began to give these polio drops, children are reaching maturity a lot earlier, especially girls," said Mir Alam Khan, 45, a carpet seller in the northern town of Dera Ismail Khan. "Now 12 to 13-year-old girls are becoming women. This causes indecency in society."
The father of four did not allow any of his children to receive vaccinations. "Why doesn't the United States give free cures for other illnesses? Why only polio? There has to be an agenda," he added.
While health workers risk attacks by militants, growing suspicions from ordinary Pakistanis are sapping their morale.
Fatima, a health worker in Peshawar, said reaction to stories of CIA involvement had been so severe that many of her colleagues quit.
"People's attitudes have changed," said the 25-year-old, who did not give her last name for fear of reprisals. "You will not believe how even the most educated and well-to-do people will turn us away, calling us US spies and un-Islamic. Boys call us names - they say we are indecent women."
Pakistan's government has tried to shatter the myths by turning to moderate clerics and urging them to issue religious rulings supporting the anti-polio efforts.
Tahir Ashrafi, the head of the All Pakistan Ulema Council, said the alliance of clerics had done its part, and it was up to the government to protect aid workers.
"Clerics can only give fatwas and will continue to come together and condemn such acts," he said. "What good are fatwas if the government doesn't provide security?"
That may be a tall order in Pakistan, where critics allege government officials are too busy lining their own pockets or locked in power struggles to protect its citizens, even children vulnerable to crippling, disfiguring diseases.
It is unclear who was behind the shootings. While the main Taliban spokesman said they were opposed to the vaccination scheme, the group has distanced itself from the attacks.
But another Taliban spokesman in South Waziristan said their fighters were behind an attack on a polio team in the north-western town of Lakki Marwat last Monday. The vaccinations were part of "a secret Jewish-American agenda to poison Pakistanis", he said.
What is clear is that the stakes are high. Any gaps in the programme endanger hard-won gains against a disease that can cause death or paralysis within hours.
A global effort costing billions of dollars eradicated polio from every country except Nigeria, Afghanistan and Pakistan.
Vaccinations cut Pakistan's polio cases from 20,000 in 1994 to only 56 in 2012. But the disease is spread person-to-person, so any outbreak risks re-infecting communities previously cleared.
Last year, a strain from Pakistan spread north-east and caused the first outbreak in China since 1999.
Oliver Rosenbauer, a spokesman for the World Health Organisation, said it been getting closer to eradicating the disease.
"For the first time, the virus had been geographically cornered," he said. "We don't want to lose the gains that had been made."