Experts at the World Health Summit highlighted health concerns related to the growth of megacities, “roughly defined as cities with a population of more than 10 million,” Agence France-Presse reports.

“Health issues found elsewhere are exacerbated in megacities. Diseases such as AIDS, SARS or H5N1 bird flu can spread like wildfire, especially through slums, where one-third of urban dwellers live. Overcrowding and poor sanitation foster tuberculosis, another major challenge facing health officials in megacities,” the news service writes.

By 2020, there will be 27 megacities, up from 19 in 2007, according to Victor Rodwin, director of the World Cities Project at New York University. Most megacities are located in Africa, Asia and South America and continue to increase in size as more people move there from rural areas. “For every minute that I speak, a new person is going to be moving into Lagos, Kinshasa or Dhaka,” said Ricky Burdett of the London School of Economics.

“We now have a new issue, a new field of study, which is the field of urban health,” Rodwin noted during a panel on megacities at the summit, which concludes on Wednesday. “Timothy Evans, from the BRAC school of public health in Bangladesh, called for more involvement with people on the ground in slums but pointed to some examples that showed improvements could be made. ‘Who is going to solve these problems? It might not be the class that is born with a golden spoon in their mouth,’ said Evans.”

Evans also highlighted a project in Dhaka, which has introduced gynecology centers into slum areas and helped halve maternal mortality rates. “Success is possible,” he said (10/11).