8. How can the threat of new and reemerging diseases and immune microorganisms be reduced?
The globalfood crisis, climate change, and pandemic influenza are the main threats tohuman health listed by WHO. Although 30% of all deaths are caused by infectiousdiseases, chronic conditions such as heart disease and stroke kill more peoplethan infectious diseases do for the first time in history because people areliving longer. However, mutations inavian flu or other communicable diseases could change this. Over the past 40years, 39 new infectious diseases have been discovered, more than 1,100epidemics have been verified in the last five years, and we face 20drug-resistant diseases today. Old diseases have reappeared, such as cholera,yellow fever, plague, dengue fever, meningitis, hemorrhagic fever, anddiphtheria. Massive urbanization and concentrated livestock production couldtrigger new global pandemics. Climate change is altering insect and diseasepatterns. Halfway to 2015, most health-related MDGs (reduce child mortality;improve maternal health; and combat HIV/AIDS, malaria, and other diseases) areunlikely to be met. Other problems may come from synthetic bacteria from genelaboratories and unknown nano-organisms.
To preventbioterrorism, R&D has increased for improved bio-sensors and generalvaccines able to boost the immune system to contain any deadly infection. Suchvaccines could be placed around the world like fire extinguishers. The4-million-person shortage of health workers is growing, people are livinglonger, and health care costs are increasing—all making tele-medicine,self-diagnosis via biochip sensors, and online expert systems increasinglynecessary. In the meantime, the best ways to address infectious diseases areearly detection, accurate reporting, prompt isolation, transparency ofinformation, rapid diagnostics, appropriate treatment, and growing globalawareness.
Meanwhile,the world is preparing for potential genetic variations in the H5N1 avian fluvirus that could be highly contagious among humans, killing tens of millions. Atwo-dose vaccine has shown positive effects against H5N1. A new approach toAsian poultry live-market businesses—the source of such viruses—is needed
Althoughhepatitis B is the most common infectious disease, with more than 2 billionpeople currently or previously infected, and although malaria kills over 1million a year, HIV/AIDS is still the largest killer in sub-Saharan Africa andits impact continues to grow in Eastern Europe and Asia. Estimates of thoseliving with HIV/AIDS have substantially decreased from 34.1–47.1 million in2006 to 30.6–36.1 million in 2007 due to recent advances in the researchmethodology of HIV statistics, natural trends in the epidemic, and preventionprograms. The number of new cases of HIV probably peaked in the late 1990s atover 3 million per year and had fallen to 2.5 million by 2007. Deaths from AIDSdropped from 2.9 million in 2006 to 2.1 million in 2007. Some 31% of theestimated 9.7 million people in need of receiving antiretroviral therapyreceived it by the end of 2007.
Two broadpatterns in HIV/AIDS are emerging: generalized epidemics in sub-Saharan Africaand more local epidemics in the rest of the world concentrated amongpopulations at risk: men who have sex with men, injecting drug users, and sexworkers and their sexual partners. The costs of antiretroviral drugs werereduced by 20% to developing countries during 2007 by Glaxo. The ClintonFoundation continues to reduce costs of second-line drugs in some areas to $100/yearand the daily one-pill to $1/day. Self-tests for AIDS cost $15, and the $40 forconfirmatory results continues to decrease. For every person who starts takingantiretroviral drugs, another 2.5 become infected, down from 5 about two yearsago. No significant positive vaccine results are yet available, but newgenetic-based vaccines and microbicides are in trial, and pre-exposuretreatment and radioactive anti-HIV antibodies show promise in animal models.Male circumcision may reduce infection by 50%.
WHO’seHealth systems, new regulations to address SARS-like threats, immunizationprograms, and the Global Outbreak Alert and Response Network are globalresponses to this challenge. Scientists are working to develop a geneticallymodified mosquito that would not carry the malaria parasite. Better tradesecurity will be necessary to prevent increased food- or animal-borne disease.Viral incidence in animals is being mapped in Africa, China, and South Asia todivert epidemics before they reach humans. Future uses of genetic data,software, and nanotechnology will detect and treat disease at the genetic ormolecular level. Meanwhile, increased investment into water, sanitation,health education, and hand washing is the most cost-effective way to reducecommunicable disease.
Africa: Although the prevalence and incidence of HIV/AIDScontinues to fall in Africa, death rates are high enough among professionals inmany countries to affect development. Patients on antiretroviral treatmentincreased from 1% in 2003 to 37% by the end of 2007. Africa is short 1 millionhealth workers. It has only 11% of the world’s population but 25% of itsdisease burden with only 3% of world health workers and 1% of world healthexpenditures. Measles decreased by 91% between 2000 and 2006 in sub-SaharanAfrica.
Asia and Oceania: About 8.6 million people in the regionhave HIV, including 2.5–5 million in India and 1–2 million in China. AIDSprograms focus on key populations and antiretroviral treatment. About 75million Asian men have commercial sex with 10 million women. Southeast Asia hasthe highest rate of TB in the world, with 3 million new cases annually.Promotion of hand washing of children in Karachi decreased impetigo by 34%,diarrhea by 53%, and pneumonia by 50%. South Koreans protest at the risk of madcow disease from imported meat. A newenterovirus outbreak in China in May 2008 quickly affected over 10,000 people.
Europe: The prevalence of HIV in Western and Central Europehas stabilized around 0.3%, as have new HIV infections at 22,000 per year andAIDS deaths at 12,000 per year. Russiaaccounted for 66% of the new HIV infections in Eastern Europe.
Latin America: About 1.6 million people have HIV in theregion, of which about 100,000 were new in 2007, while 58,000 died of AIDS lastyear. The region provides AIDS treatment to 72% of those in need. Brazil hasoffered free antiretroviral treatment since 1996, saving billions of dollars inhospital costs. Latin America has the highest life expectancy among developingregions, the infant mortality rate reduced from 54 deaths per 1,000 live birthsin 1991 to 31 in 2005, and 89% of births in the region are now attended byskilled health care personnel.
North America: Genetics-based and molecular research inNorth America will affect prevention, diagnosis, and treatment of a largenumber of diseases. Over a million people in the U.S. and 62,000 in Canada wereHIV-positive at the beginning of 2007. Antiretroviral medications keep AIDSdeath rates low. Increased food imports raise vulnerability to infections fromoverseas.
Figure 6.Physician density (per 10,000 populations)
Source: World Health Organization, Core Health Indicators