An earthquake killing up to 200,000 people would have been bad enough anywhere, but in Haiti, where AIDS, tuberculosis and malaria are rampant, it may create one of the worst medical disasters ever.
Medical teams pouring in to set up mobile hospitals say they are already overwhelmed by the casualties and fear the worst is far from over.
Haitian government officials say the death toll from Tuesday's magnitude seven quake is likely to be up to 200,000, and nobody has even begun to count the injuries, including crushed or amputated limbs, compound fractures and lacerations.
Without quick treatment, these wounds will become infected.
[Medecines Sans Frontieres Doctor]:
"Lots of the injuries are open fractures, which will need a rapid amputation if we don't want gangrene, bacterial decay or septic problems."
If there is no room in field hospitals, then treatment is provided in makeshift hospitals, where operating rooms are sectioned off with sheets. Every effort is made to avoid unsafe buildings that are still standing.
"When the quake happened, the building suffered, it is an old construction, and it is now riddled with cracks, especially the second floor, so we won't go in, we have condemned it."
Medical teams flew-in mobile hospitals and supplies, but have often been unable to get them set up because roads are destroyed and security is lacking.
Haiti has struggled for decades with political turmoil and conflict, grinding poverty and devastating natural disasters, such as floods and landslides.
The United States and the United Nations are spearheading a huge relief operation for the quake victims. International donors are preparing more meetings to coordinate financial assistance to the Caribbean country.