Muslims should take all necessary measures to protect themselves against all forms of infection and disease. If diseases begin to spread in the devastated areas, people living there are permitted to leave the place for a more secure and infection-free area.
Dr. Rif`at Fawzi, professor of Shari`ah at Cairo University states the following: In the first place, I would like to stress that if a certain disease appears as a result of the aftermath of the Asian quake and tsunami, people living in the affected area can leave it for another area to protect themselves. This is just a protective measure to save themselves from epidemics and diseases.

Moreover, the eminent scholar and renowned da`iyahSheikh `Abdel Khaliq Hasan Ash-Shareef adds:

In case devastation and epidemics began to spread as a result of the tidal waves in some Asian countries, a Muslim living there is permitted to shift to a safe place to protect himself and there is nothing wrong with that, in sha’ Allah.
As for the relief workers, they are urged to exert sincere efforts to protect the people and they should not run away. Realistically speaking, those workers are usually provided with necessary safety equipments which protect them against any possible hazards.