UKHIA (Bangladesh) • In a makeshift bamboo clinic, small children struggle to draw breath through surgical masks, victims of a forgotten but deadly disease that has torn through the teeming Rohingya refugee camps in Bangladesh.
Diphtheria had been all but eradicated in Bangladesh until last year, when more than 650,000 Rohingya poured across the border fleeing a bloody military crackdown in neighbouring Myanmar.
Packed into an area meant for a much smaller number of refugees, and with little sanitation or healthcare, the new arrivals provided fertile ground for the highly contagious respiratory disease to take hold.
It quickly spread through the camps, with the World Health Organisation (WHO) reporting more than 3,600 cases.
The outbreak has already claimed the lives of at least 30 refugees, mostly children, while a handful of Bangladeshis living near the camps have also contracted the disease.
Ms Carla Pla, head nurse at the specialist diphtheria unit run by medical charity Doctors Without Borders (MSF), said children were arriving with "severe" symptoms.
"This is a very challenging situation because every day there are more children coming. The challenge to get the vaccine is also something that is very difficult," she said.
Nearly 600 refugees have been referred there since it opened last month, putting enormous pressure on doctors who also struggle to treat rampant malnutrition, water-borne disease and other diseases.
Bangladesh authorities were prepared for other diseases and moved quickly to inoculate the new arrivals against cholera and measles to prevent a health disaster.
This is a very challenging situation because every day there are more children coming. The challenge to get the vaccine is also something that is very difficult.
MS CARLA PLA, head nurse at the specialist diphtheria unit run by medical charity Doctors Without Borders, saying that children were arriving with "severe" symptoms.
But the emergence of diphtheria, which causes difficulty breathing and can lead to heart failure, paralysis and death, if left untreated, caught aid workers off guard.
"We were taken aback when tests confirmed diphtheria in the camps. It was a long-lost disease in our country," said Mr Abdus Salam, chief medical officer for Cox's Bazar district, where the camps are located.
Last month, they launched a huge vaccination push. Nearly 320,000 children aged under 15 have now been inoculated and another 160,000 children are expected to receive the vaccine this month.
The Rohingya come from impoverished Rakhine state, where state-imposed restrictions have ensured abysmal living standards for the persecuted Muslim community and many children are not vaccinated.
Mr Mohammad Hossain assumed his son, now being treated in the MSF clinic, had the same minor throat infection affecting other Rohingya children in the refugee camp. "I thought it was tonsillitis. But the doctors said it was more serious," he said, wearing a protective mask as he tended to the 11-year-old.
Seven specialist diphtheria field clinics have been set up to treat the rising number of patients since the outbreak, said WHO's South-east Asia emergency director Roderico Ofrin.
Together, the wards house 400 beds for patients but a shortage of doctors has required medics to be flown in from Britain and elsewhere to help fight the outbreak.
Treatment involves administering an antitoxin and antibiotics.
Preventing infected patients from coming into contact with the wider, largely unvaccinated population of Rohingya remains a priority, doctors said.