The focus of public health interventions is to prevent and manage diseases, injuries and other health conditions through surveillance of cases and the promotion of healthy behavior, communities, and (in aspects relevant to human health) environments. Its aim is to prevent health problems from happening or re-occurring by implementing educational programs, developing policies, administering services and conducting research.[53] In many cases, treating a disease or controlling a pathogen can be vital to preventing it in others, such as during an outbreak. Vaccination programs and distribution of condoms to prevent the spread of communicable diseases are examples of common preventive public health measures, as are educational campaigns to promote vaccination and the use of condoms (including overcoming resistance to such).
Continuing weight loss may deteriorate into wasting, a vaguely defined condition called cachexia.[30] Cachexia differs from starvation in part because it involves a systemic inflammatory response.[30] It is associated with poorer outcomes.[25][30][31] In the advanced stages of progressive disease, metabolism can change so that they lose weight even when they are getting what is normally regarded as adequate nutrition and the body cannot compensate. This leads to a condition called anorexia cachexia syndrome (ACS) and additional nutrition or supplementation is unlikely to help.[27] Symptoms of weight loss from ACS include severe weight loss from muscle rather than body fat, loss of appetite and feeling full after eating small amounts, nausea, anemia, weakness and fatigue.[27]
Public health also takes various actions to limit the health disparities between different areas of the country and, in some cases, the continent or world. One issue is the access of individuals and communities to health care in terms of financial, geographical or socio-cultural constraints to accessing and using services.[54] Applications of the public health system include the areas of maternal and child health, health services administration, emergency response, and prevention and control of infectious and chronic diseases.