A health worker administers polio vaccine to a child in Karachi, Pakistan, late last month. Pakistan has reached its highest rate of polio transmission in more than a dozen years. (Rehan Khan/European Press Agency)

As world health officials struggle to respond to the Ebola epidemic, Pakistan has passed a grim milestone in its efforts to combat another major global health crisis: the fight against polio.

Over the weekend, Pakistan logged its 200th new polio case of 2014, the nation’s highest transmission rate in more than a dozen years. The spread has alarmed Pakistani and international health experts and is prompting fresh doubt about the country’s ability to combat this or future disease outbreaks.

By Tuesday, the number of new polio cases in Pakistan stood at 202, and officials are bracing for potentially dozens of other cases by year’s end. Pakistan now accounts for 80 percent of global cases and is one of only three countries at risk of exporting the disease outside its borders, according to the World Health Organization.

“It’s an emergency, a public health emergency,” said Ayesha Raza Farooq, the polio eradication coordinator for Pakistan’s government. “We want to limit the virus outside of our boundaries and want to work to control it in our boundaries, but it’s certainly a very challenging situation ahead.”

Pakistan has struggled for years to shed its title as one of the last remaining countries with an active polio virus, mostly because of troubles it faces in vaccinating children.

A polio worker administers vaccine drops to a boy in Karachi, Pakistan, in March. Pakistan’s polio eradication coordinator said that the nation’s growing polio crisis is a “public health emergency.” (Akhtar Soomro/Reuters)

In far-flung areas of the country, some parents and religious leaders are skeptical of the vaccine, requiring considerable face-to-face outreach by vaccination teams.

But the Pakistani Taliban and other Islamist militants have waged a brutal campaign against those teams, killing more than 50 health workers and security officials since 2012. The attacks began after it was discovered that the CIA had used a vaccination campaign to gain information about Osama bin Laden’s whereabouts.

In May, after new polio cases in Iraq and Syria were linked to travelers from Pakistan, the WHO declared Pakistan’s polio crisis an “extraordinary event” mandating an immediate international response. Ebola is the only other disease that is currently designated by the WHO as a global public health emergency.

In response to the WHO declaration, Prime Minister Nawaz Sharif vowed to redouble efforts to vaccinate children through house-to-house searches and checkpoints along major travel routes. Pakistan also set up mandatory polio vaccination clinics at airports.

But those efforts were quickly overwhelmed by the country’s continued battle against terrorism, as well as months of political chaos in the capital, Islamabad.

After the Pakistani military launched an operation against militants in North Waziristan in June, more than 1 million residents fled their homes and resettled in other areas of the country. The displaced included about 350,000 children who health officials fear have never been vaccinated.

“It’s like if you break the walls on a dam, the waters come down on the village,” said Bilal Ahmed, a UNICEF health specialist in northwestern Pakistan. “There was high movement of the virus.”

Relief workers were able to administer 700,000 vaccinations to displaced residents this summer. But advocates say the government was distracted by last month’s protests in Islamabad calling on Sharif to resign, hampering follow-through on the country’s polio eradication efforts.

But the capital is again calm, and health experts say they hope Sharif is capable of confronting the polio threat.

Aziz Memon, chairman of the Pakistan PolioPlus Committee, said he met with senior government leaders last week and gave them a dire assessment of the problem.

“I explained to them: This is no longer an emergency. This has become an outbreak,” Memon said. “The government needs to take full ownership . . . and it needs to be done on a war footing.”

Though the United States eradicated polio within its borders by 1979, there remained more than 350,000 cases worldwide as recently as 1988.

Over the past two decades, however, the global fight against polio has made enormous strides. The virus remains endemic in only Pakistan, Nigeria and Afghanistan. Afghanistan has recorded 10 cases this year while Nigeria has recorded six, according to the Global Polio Eradication Initiative.

Because of lackluster vaccination protocols and security, the WHO believes Pakistan, Syria and Cameroon are the only countries at risk of exporting the disease.

In Pakistan, officials say they are optimistic that they can make considerable progress vaccinating children this winter and spring.

They point to neighboring India, which this year was declared polio-free. As recently as 2009, there were more than 700 annual polio cases in India. But after an aggressive immunization program, that number had dropped to 74 in 2010 and just one in 2011, officials said.

Ahmed and other UNICEF officials said a key focus will be recruiting more women to serve on the vaccination teams. In conservative and rural parts of the country, he said, parents are more prone to allow a woman into the house than a man.

Still, it remains unclear if such efforts will be enough to prevent the WHO from issuing formal travel restrictions or other sanctions against Pakistan.