facing the world today, including hiv/aids, diabetes, waterborne diseases, zoonotic diseases, and antibiotic resistance leading to the reemergence of infectious diseases such as tuberculosis. antibiotic resistance, also known as drug resistance, was the theme of world health day 2011. for example, the who reports that at least 220 million people worldwide have diabetes. its incidence is increasing rapidly, and it is projected that the number of diabetes deaths will double by 2030. in a june 2010 editorial in the medical journal the lancet, the authors opined that "the fact that type 2 diabetes, a largely preventable disorder, has reached epidemic proportion is a public health humiliation." the risk of type 2 diabetes is closely linked with the growing problem of obesity. the who's latest estimates as of june 2016 highlighted that globally approximately 1.9 billion adults were overweight in 2014, and 41 million children under the age of five were overweight in 2014. once considered a problem in high-income countries, it is now on the rise in low-income countries, especially in urban settings. many public health programs are increasingly dedicating attention and resources to the issue of obesity, with objectives to address the underlying causes including healthy diet and physical exercise. the national institute for health and care research (nihr) has published a review of research on what local authorities can do to tackle obesity. the review covers interventions in the food environment (what people buy and eat), the built and natural environments, schools, and the community, as well as those focussing on active travel, leisure services and public sports, weight management programmes, and system-wide approaches. current practice world health organization (who) the world health organization (who) is a specialized agency of the united nations responsible for international public health. the who constitution, which establishes the agency's governing structure and principles, states its main objective as "the attainment by all peoples of the highest possible level of health". the who's broad mandate includes advocating for universal healthcare, monitoring public health risks, coordinating responses to health emergencies, and promoting human health and well-being. the who has played a leading role in several public health achievements, most notably the eradication of smallpox, the near-eradication of polio, and the development of an ebola vaccine. its current priorities include communicable diseases, particularly hiv/aids, ebola, covid-19, malaria and tuberculosis; non-communicable diseases such as heart disease and cancer; healthy diet, nutrition, and food security; occupational health; and substance abuse. others most countries have their own governmental public health agency, often called the ministry of health, with responsibility for domestic health issues. for example, in the united states, state and local health departments are on the front line of public health initiatives. in addition to their national duties, the united states public health service (phs), led by the surgeon general of the united states public health service, and the centers for disease control and prevention, headquartered in atlanta, are also involved with international health activities. public health programs most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging and other physical and mental health conditions. however, public health generally receives significantly less government funding compared with medicine. although the collaboration of local health and government agencies is considered best practice to improve public health, the pieces of evidence available to support this is limited. public health programs providing vaccinations have made major progress in promoting health, including substantially reducing the occurrence of cholera and polio and eradicating smallpox, diseases that have plagued humanity for thousands of years. three former directors of the global smallpox eradication program reading the news that smallpox had been globally eradicated, 1980 the world health organization (who) identifies core functions of public health programs including: providing leadership on matters critical to health and engaging in partnerships where joint action is needed; shaping a research agenda and stimulating the generation, translation and dissemination of valuable knowledge; setting norms and standards and promoting and monitoring their implementation; articulating ethical and evidence-based policy options; monitoring the health situation and assessing health trends. in particular, public health surveillance programs can: serve as an early warning system for impending public health emergencies; document the impact of an intervention, or track progress towards specified goals; and monitor and clarify the epidemiology of health problems, allow priorities to be set, and inform health policy and strategies. diagnose, investigate, and monitor health problems and health hazards of the community behavior change main article: behavior change (public health) many health problems are due to maladaptive personal behaviors. from an evolutionary psychology perspective, over consumption of novel substances that are harmful is due to the activation of an evolved reward system for substances such as drugs, tobacco, alcohol, refined salt, fat, and carbohydrates. new technologies such as modern transportation also cause reduced physical activity. research has found that behavior is more effectively changed by taking evolutionary motivations into consideration instead of only presenting information about health effects. the marketing industry has long known the importance of associating products with high status and attractiveness to others. films are increasingly being recognized as a public health tool. in fact, film festivals and competitions have been established to specifically promote films about health. conversely, it has been argued that emphasizing the harmful and undesirable effects of tobacco smoking on other persons and imposing smoking bans in public places have been particularly effective in reducing tobacco smoking. applications in health care as well as seeking to improve population health through the implementation of specific population-level interventions, public health contributes to medical care by identifying and assessing population needs for health care services, including: assessing current services and evaluating whether they are meeting the objectives of the health care system ascertaining requirements as expressed by health professionals, the public and other stakeholders identifying the most appropriate interventions considering the effect on resources for proposed interventions and assessing their cost-effectiveness supporting decision making in health care and planning health services including any necessary changes. informing, educating, and empowering people about health issues conflicting aims some programs and policies associated with public health promotion and prevention can be controversial. one such example is programs focusing on the prevention of hiv transmission through safe sex campaigns and needle-exchange programs. another is the control of tobacco smoking. changing smoking behavior requires long-term strategies, unlike the fight against communicable diseases, which usually takes a shorter period for effects to be observed. many nations have implemented major initiatives to cut smoking, such as increased taxation and bans on smoking in some or all public places. supporters argue by presenting evidence that smoking is one of the major killers, and that therefore governments have a duty to reduce the death rate, both through limiting passive (second-hand) smoking and by providing fewer opportunities for people to smoke. opponents say that this undermines individual freedom and personal responsibility, and worry that the state may be encouraged to remove more and more choice in the name of better population health overall. psychological research confirms this tension between concerns about public health and concerns about personal liberty: (i) the best predictor of complying with public health recommendations such as hand-washing, mask-wearing, and staying at home (except for essential activity) during the covid-19 pandemic was people's perceived duties to prevent harm but (ii) the best predictor of flouting such public health recommendations was valuing liberty more than equality. simultaneously, while communicable diseases have historically ranged uppermost as a global health priority, non-communicable diseases and the underlying behavior-related risk factors have been at the bottom. this is changing, however, as illustrated by the united nations hosting its first general assembly special summit on the issue of non-communicable diseases in september 2011. global perspectives a village health worker in zimbabwe conducting a pediatric examination disparities in service and access there is a significant disparity in access to health care and public health initiatives between developed countries and developing countries, as well as within developing countries. in developing countries, public health infrastructures are still forming. there may not be enough trained health workers, monetary resources or, in some cases, sufficient knowledge to provide even a basic level of medical care and disease prevention. as a result, a large majority of disease and mortality in developing countries results from and contributes to extreme poverty. for example, many african governments spend less than us$10 per person per year on health care, while, in the united states, the federal government spent approximately us$4,500 per capita in 2000. however, expenditures on health care should not be confused with spending on public health. public health measures may not generally be considered "health care" in the strictest sense. for example, mandating the use of seat belts in cars can save countless lives and contribute to the health of a population, but typically money spent enforcing this rule would not count as money spent on health care. a malaria test in kenya. despite being preventable and curable, malaria is a leading cause of death in many developing nations. large parts of the world remained plagued by largely preventable or treatable infectious diseases. in addition to this however, many developing countries are also experiencing an epidemiological shift and polarization in which populations are now experiencing more of the effects of chronic diseases as life expectancy increases, the poorer communities being heavily affected by both chronic and infectious diseases. another major public health concern in the developing world is poor maternal and child health, exacerbated by malnutrition and poverty. the who reports that a lack of exclusive breastfeeding during the first six months of life contributes to over a million avoidable child deaths each year. intermittent preventive therapy aimed at treating and preventing malaria episodes among pregnant women and young children is one public health measure in endemic countries. since the 1980s, the growing field of population health has broadened the focus of public health from individual behaviors and risk factors to population-level issues such as inequality, poverty, and education. modern public health is often concerned with addressing determinants of health across a population. there is a recognition that health is affected by many factors including class, race, income, educational status, region of residence, and social relationships; these are known as "social determinants of health". the upstream drivers such as environment, education, employment, income, food security, housing, social inclusion and many others effect the distribution of health between and within populations and are often shaped by policy. a social gradient in health runs through society. the poorest generally have the worst health, but even the middle classes will generally have worse health outcomes than those of a higher social level. the new public health advocates for population-based policies that improve health in an equitable manner. the health sector is one of europe's most labor-intensive industries. in late 2020, it accounted for more than 21 million employment in the european union when combined with social work. according to the who, several countries began the covid-19 pandemic with insufficient health and care professionals, inappropriate skill mixtures, and unequal geographical distributions. these issues were worsened by the pandemic, reiterating the importance of public health. in the united states, a history of underinvestment in public health undermined the public health workforce and support for population health, long before the pandemic added to stress, mental distress, job dissatisfaction, and accelerated departures among public health workers. health aid in developing countries further information: aid and global health initiatives a cuban doctor performs an open air operation in guinea-bissau. cuba sends more medical personnel to the developing world than all g8 countries combined. health aid to developing countries is an important source of public health funding for many developing countries. health aid to developing countries has shown a significant increase after world war ii as concerns over the spread of disease as a result of globalization increased and the hiv/aids epidemic in sub-saharan africa surfaced. from 1990 to 2010, total health aid from developed countries increased from 5.5 billion to 26.87 billion with wealthy countries continuously donating billions of dollars every year with the goal of improving population health. some efforts, however, receive a significantly larger proportion of funds such as hiv which received an increase in funds of over $6 billion between 2000 and 2010 which was more than twice the increase seen in any