Global Burden of Infectious Diseases

Systematic efforts to quantify and monitor the burden of specific health conditions in populations, at the national level, started in the mid-1950s for malaria, poliomyelitis, and influenza in the United States. Comprehensive surveillance of morbidity and mortality for dozens of conditions has since been well established in the United States and in other industrialized countries. However, despite the clear need for epidemiological data to inform health policies, reliable and comprehensive health statistics are not available in many developing countries. International efforts to assess and monitor the burden of certain diseases have been limited in the past to a small number of infectious diseases in the context of global eradication programs – smallpox, poliomyelitis, guinea worm, and, more recently, HIV/AIDS, severe acute respiratory syndrome (SARS), and avian flu influenza A (H5N1). The Global Burden of Disease Study (GBD), published in 1996, filled an important gap in our knowledge of population health status. It created a common metric, the disability-adjusted life year (DALY), to estimate morbidity and mortality for eight regions that collectively span the world’s population, generating comparable information on incidence and prevalence in global health. However, patterns of disease, disability, and risk factors have since changed significantly and new data on their distribution are available. Furthermore, the unprecedented money and attention now pouring into international health has made an accurate assessment of global health patterns a matter of utmost urgency. The new Global Burden of Diseases, Injuries, and Risk Factors (GBD 2005) project, which began in 2007, represents the first major effort at a systematic revision of estimates in health for every region in the world comprehensively, and will ensure that that the global health community bases its research and policies on complete, valid, and reliable information. Burden of disease estimates provided in this article are for 2001 – the year for which the most recent estimates of the global burden of disease and risk factors are currently available. Causes of deaths were categorized into three main groups: group I (infectious diseases and maternal, perinatal, and nutritional conditions), group II (noncommunicable diseases), and group III (injuries). Accordingly, estimates of the global burden of infectious diseases are provided in the context of the overall burden from other conditions, diseases, and injuries. The relative importance of the burden of infectious diseases was forecasted to change by 2020. As the epidemiological transition progresses worldwide, a decline in the burden of infectious diseases is expected as the burden of noncommunicable diseases and injuries gradually increases. The pace of the epidemiological transition, however, varies greatly among regions so that the projected decreases in the burden of infectious diseases are expected to vary between regions. Trends in the global burden due to specific infectious diseases projected to 2020 also vary among specific conditions. The global burden of HIV/AIDS, for instance, is expected to greatly increase, whereas the global burden due to respiratory infections and diarrheal diseases is expected to decrease. Contrary to expectations, the global burden of malaria has increased in recent years.