Human populations are impacted by infectious diseases that spread due to various factors such as demographics, human behavior, international travel, land use, infrastructure, migration, and urbanization. Developing countries are most affected, with death rates from infectious diseases almost 14 times higher in low-income countries. Emerging diseases originating in wildlife pose a growing threat and have increased in recent years. Infectious diseases can significantly alter the age structure of affected populations. The Philippines faces threats from diseases like Henipavirus, West Nile fever, MERS, hantavirus, and avian flu, and responds through surveillance, prevention and control programs, infrastructure development, and research.