Urgent care for survivors, sheltering the sick and homeless and warding off the spectre of infectious disease head an almost endless list of medical needs in quake-devastated Haiti, experts said on Thursday.
Doctors face a race against time to save people suffering from fractures and internal injuries caused by falling masonry and treat open wounds that can swiftly develop into life-threatening infection, they said.
"Many other quakes have shown us very clearly that of people who suffer injuries and die as a result, most deaths occur within the first 72 hours," said Tammam Aloudat, an emergencies specialist at the International Federation of Red Cross and Red Crescent (IFRC) Societies in Geneva.
"We are entering a critical period. There must be massive humanitarian aid arriving this evening," said Olivier Bernard, president of French medical relief charity Medecins du Monde (Doctors of the World).
Partners in Health, an American medical NGO working on the ground in Haiti, issued an emergency appeal to its pool of volunteers.
"We need surgeons (especially trauma/orthopedic surgeons), ER [emergency room] doctors and nurses, and full surgical teams (including anesthesiologists, scrub and post-op nurses, and nurse anesthetists)," it said on its website.
Even before the disaster, the health infrastructure in Haiti, the western hemisphere's poorest country, was meagre.
Its 9.8 million people are prey to a twin epidemic of AIDS and tuberculosis and a sky-high maternal mortality rate. Only one person in two has access to clean drinking water and only 19 percent have decent sanitation.
"On a good day, Port-au-Prince is a major public health concern," commented Caroline Hotham of Oxfam, who worked as the charity's humanitarian coordinator in Haiti until last May.
Haiti's slender medical means were further diminished by the 7.0-magnitude quake that struck Port-au-Prince, the Haitian capital, on Tuesday.
"At least eight hospitals and health facilities in and around Port-au-Prince have been damaged or destroyed," said Paul Garwood of a World Health Organisation (WHO) unit, Health Action in Crises.
"Roads are blocked by rubble, so cars, vehicles, ambulances can't reach those in need. WHO staff, for example, are going by foot to the central drugs store to get essential medicines and take them to health facilities."
Resolving major logistical headaches in power, water, telecommunications and food supplies will determine the fate of many survivors in the coming weeks, these sources said.
Dysentery, measles, mosquito-borne diseases, dengue, tuberculosis, influenza and other respiratory infections already lurk in Haiti and have ample means to spread among those who are weak or in poor health, living in the street or in cramped rooms.
"There is a whole range of communicable diseases that will almost invariably rise over the coming days and weeks," said Aloudat. "There is a very high likelihood of outbreaks of diarrhoeal diseases. That is a major concern."
Hotham added: "There is always a cholera concern. Port-au-Prince is already a high-risk area for dengue under normal circumstances."
Brigitte Vasset, a physician with the French first-response charity Medecins Sans Frontieres (MSF, Doctors Without Borders) emphasised the need to address longer-term basics after the rush to extricate survivors.
"The sooner there is shelter, water and food, the less disease there will be," she said.
Aloudat pointed out that some health dilemmas were less visible. They included poor people on life-supporting drugs such as anti-HIV medication who were unable to get the treatment because the supply line had been disrupted.