Decades after polio has been eradicated from Papua New Guinea, the crippled and sometimes deadly disease returns, leaving doctors to revive long-term vaccination programs.
By the beginning of this year, the polio virus was endemic in only three countries in the world: Afghanistan, Nigeria and Pakistan.
But, the relatively rare species is now spreading through the solid Papua New Guinea, one of the poorest countries in the world.
Since the first case was discovered in April – paralyzing a six-year-old boy named Gaffo near the north coast – polio has infested dozens more nationally, prompting the government to declare a national emergency.
Papua New Guinea, which today has a population of about eight million people, says it has matched the wild variant of the virus in 1996 and was certified without polio in 2000.
But since then, experts say, programs to stop vaccination and poor sanitation have left an open invitation to a prehistoric disease to return.
"It's not a sudden surprise," said Monzur Hossen, a UNICEF expert living in Port Morebie.
"The government knew about it," he told AFP. "We all knew about it."
In a cruel turnaround, the virus that struck Papua New Guinea today – clinically known as VDPV1 – started life as a vaccine.
A very weakened version of the polio virus is first ingested as an oral vaccine, before spreading throughout the community through excrement.
Due to low levels of immunization, a harmless attenuated virus continued to circulate face-to-face for a long time, allowing it to mutate into a more virulent virus.
Similar localized polio vaccine epidemics were previously detected in the Horn of Africa, Syria and the Democratic Republic of the Congo.
However, health professionals are adamant that the benefits of vaccination programs massively exceed the risk of polio.
World Health Organization experts estimated that over 10 million cases of polio were prevented worldwide, as widespread vaccinations began two decades ago, a decrease of 99 percent.
But even with modern treatment, about 100 cases of polio results result in irreversible paralysis. Some of those paralyzed are dying.
Doctors in Papua New Guinea are trying to respond to the crisis by providing immunization to the country – with at least three oral doses for each child.
Hundreds of thousands have already been vaccinated.
Despite government and international support, the lack of roads and the unforgiving terrain of the country, especially in the central highlands, made it difficult.
Many villages can only be reached by air, or by one-day river trips.
Throw in a mix of tribal violence, malnutrition, drought, multiple outbreaks of other diseases like measles and the aftermath of the massive earthquake in February, and things get even harder.
"It is indeed a challenge to the approach, in terms of logistics," said Hosen. "It's very expensive and very difficult."
One of the answers is to create mobile clinics traveling to villages away from populated areas such as Hagen Mountain – which has very few paved roads.
In one such clinic near the Hagen Mountain market, healthcare worker Margaret Akima practically pulls mothers and their children into her bay bikes trailer.
In the first few days after setting, it administered more than 100 doses of polio vaccine per day. By the last day of the two-week stay, it's up to about 50.
From the middle of the annoying men – fighting, shouting and playing darts – Akima chooses 37-year-old Mary Pond.
She traveled to Mount Hagen with her six-year-old daughter Varapanong to buy a paddle head.
"I did not expect her to be vaccinated," said Pond, while the dose was given to her daughter.
Warapnong has already missed a few courses from the vaccine and only received this case of happiness, emphasizing how the skeptic is the answer.