Global Challenges Facing Humanity
8. Health: How can the threat of new and reemerging diseases and immune microorganisms be reduced?
Even though population is increasing, 30% fewer children under five died in 2008 than in 1990 and total mortality from infectious disease fell from 25% in 1998 to 16% in 2008. Vaccines supplied by UNICEF reach 55% of the world’s children. Partnerships between the Global Alliance for Vaccines and Immunization and the Gates Foundation, WHO, UNICEF, and the World Bank have greatly improved global health cooperation over the past 10 years.
Because the world is aging and increasingly sedentary, cardiovascular disease is now the leading cause of death in the developing as well as the industrial world; however, infectious diseases are the second largest killer and cause about 67% of all preventable deaths of children under five (pneumonia, diarrhea, malaria, and measles). Urbanization, travel, trade, increased encroachment on animal territory, and concentrated livestock production move infectious organisms to more people in less time than ever before and could trigger new pandemics.
The H1N1 virus (swine flu) infected millions of humans in all 214 countries and territories within a year, killing 18,000, and will be active another year. Although spreading very fast, the mortality was relatively low, causing WHO to review its decision to declare it a pandemic. H5N1 (avian flu) killed half of the people infected, spread very slowly, has mutated three times in the last 15 years, and could mutate again, increasing its impact. Over the past 40 years, 39 new infectious diseases have been discovered, 20 diseases are now drug-resistant, and old diseases have reappeared, such as cholera, yellow fever, plague, dengue fever, meningitis, hemorrhagic fever, and diphtheria. In the last five years, more than 1,100 epidemics have been verified. About 75% of emerging pathogens are zoonotic (they jump species).
Some 33 million people are living with HIV/AIDS; 2.7 million were newly infected and 2 million died during 2009. The virus is unstable and mutates enough that $800 million of research has not produced a successful vaccine. So far, it cannot be cured, only stabilized, and it has become resistant to multiple drugs. While it appears that new cases peaked in the late 1990s and mortality peaked in 2004, predictions of 2.3 million new cases per year are likely to be true into the 2030s unless prevention is more successful. Sharing needles is thought to be three times more likely than sexual intercourse to transmit HIV; male circumcision may reduce infection by 50%; and since HIV crosses the placenta and breast milk to children, preventive treatments are important.
While small numbers of people with Ebola and West Nile viruses have receive media attention, the bigger health impacts are from schistosomiasis (200 million cases), dengue fever (50 million new cases a year), measles (30 million cases a year), onchocerciasis (18 million cases in Africa), typhoid and leishmaniasis (approximately 12 million each globally), rotavirus (600,000 child deaths per year), and shigella childhood diarrhea (600,000 deaths per year). About half of the world’s population is at risk of several endemic diseases. Climate change is altering insect and disease patterns. Vector reproduction, parasite development cycle, and bite frequency generally rise with temperature; therefore, malaria, tick-borne encephalitis, and dengue fever are expected to become increasingly widespread. Hepatitis B infects up to 2 billion people. There is more TB in the world now than ever before (2 million deaths, 9 million new infections in 2009), yet in the last 15 years 43 million TB cases have been treated and 36 million have been cured. There were 863 000 malaria deaths in 2009 (80% occurred in children younger than 5 in sub-Saharan Africa), yet 38 countries (9 in Africa) documented reductions of more than 50% in the number of malaria cases between 2000 and 2008. Enhanced optimism and a marked increase in funding for malaria control have prompted calls for malaria eradication.
To counter bioterrorism, R&D has increased for improved bio-sensors and general vaccines able to boost the immune system to contain any deadly infection. Such vaccines could be placed around the world like fire extinguishers. Some small viruses have been found to attack large viruses, offering the possibility of a new route to disease cures. Other problems may come from synthetic biology laboratories of the future. In the meantime, the global shortage of 4.3 million health workers is growing. People are living longer and health care costs are increasing, making tele-medicine and self-diagnosis via biochip sensors and online expert systems increasingly necessary.
At the moment, the best ways to address infectious diseases remain early detection, accurate reporting, prompt isolation, transparency of information, increased investment in clean drinking water, sanitation, and handwashing. Also are WHO’s eHealth systems, International Health Regulations to address SARS-like threats, immunization programs, and the Global Outbreak Alert and Response Network as global responses to this challenge. Scientists are working to develop a genetically modified mosquito that would not carry the malaria parasite. Better trade security will be necessary to prevent increased food- or animal-borne disease. Viral incidence in animals is being mapped in Africa, China, and South Asia to divert epidemics before they reach humans. Future uses of genetic data, software, and nanotechnology will help detect and treat disease at the genetic or molecular level.
If Asian poultry farmers received incentives to replace their live-market businesses—the source of some viruses—with frozen-products markets, the annual loss of life and economic impacts could be reduced. WHO’s eHealth systems, International Health Regulations to address SARS-like threats, immunization programs, and the Global Outbreak Alert and Response Network are global responses to this challenge. Scientists are working to develop a genetically modified mosquito that would not carry the malaria parasite. Better trade security will be necessary to prevent increased food- or animal-borne disease. Viral incidence in animals is being mapped in Africa, China, and South Asia to divert epidemics before they reach humans. Future uses of genetic data, software, and nanotechnology will help detect and treat disease at the genetic or molecular level.
Regional Considerations
Africa: With 11% of the world's population, Africa has 25% of the world's disease burden, 3% of its health workers, and 1% of its health expenditures. Sub-Saharan Africa accounted for 66% of all people living with HIV and 75% of all deaths from AIDS in 2009; it has one of the world's worst tuberculosis epidemics, compounded by rising drug resistance and HIV co-infection. Although the prevalence and incidence of HIV/AIDS continues to fall in Africa, death rates are high enough among professionals to slow African development. Patients on antiretroviral treatment increased from 1–2% in 2003 to 48% by the end of 2009.
Asia and Oceania: Asia is an epicenter of emerging epidemics. Avian flu outbreaks were reported in China, Vietnam, and Indonesia during 2009 and thousands of H1N1 (swine flu) cases were reported throughout the region. China responded with a mass vaccination program at a speed and scale unparalleled in history. It is spending $125 billion over the next three years to support health care reform. Although total statistics for the region may not be reliable, at least 5 million people have HIV/AIDS and, with increases in India and China, this could reach 10 million in several years. Japan's life expectancy at birth in 2008 was 82 years; in China it was 73; in Macau it was 84.
Europe: The aging population of Europe continues to pressure government medical services, while infant mortality under five was cut in half since 1990 and maternal mortality dropped by one-fourth. TB deaths continue to increase in Europe after a 40-year decline, due to increasing HIV/AIDS in Eastern Europe caused mostly by IV drug use. Russian officials have given special recognition to World Vision's HIV prevention programs.
Latin America: The region has the highest life expectancy among developing regions (75.5 years in 2008). The HIV/AIDS epidemic remains stable with 2 million people and 0.6% prevalence, and antiretroviral therapy is at almost 60%. Brazil has shown that free antiretroviral therapy since 1996 dramatically cut AIDS mortality, extended survival time, saved $2 billion in hospital costs, and keep prevalence to 0.6%. Smaller countries such as Belize, Guyana, and Suriname have prevalence rates between 2.1 and 2.5%. Haiti's rate has fallen from over 6% to 2.2% over the last 10 years. Neglected tropical diseases affect 200 million people in Latin America (intestinal worms, Chagas, schistosomiasis, trachoma, dengue fever, leishmaniasis, lymphatic filariasis, and onchocerciasis).
North America: In June 2009 influenza surveillance information showed the U.S. had nearly 28,000 laboratory-confirmed "H1N1/09" cases and 127 deaths, but mathematical modeling showed an estimated 1 million Americans had the 2009 pandemic flu. The U.S. has 1.2 million people with HIV; Canada has 73,000. About 33% of children in the U.S. are overweight or obese, and one survey found that children aged 8–18 years spend on average 7.5 hours a day with entertainment media. The leading causes of death are heart disease and cancer. Genetics-based and molecular research in North America will affect prevention, diagnosis, and treatment of a large number of diseases. Increased food and worldwide mobility raise vulnerability to new infections from overseas. Court rulings based on Mayo Clinic research denied any connection between immunization and autism or related mitochondrial disorders, which it is hoped will stem the global vaccination/autism fears.