Infectious Diseases

a persistent threat


The Challenge
| The Response | Opportunities for U.S. Engagement

The Challenge

Worldwide, infectious diseases are the leading cause of death of children and adolescents, and one of the leading causes in adults.

Three of the top ten causes of death, or sixteen percent of all deaths each year, are from infectious diseases . Most of these deaths are in low- and middle-income countries and are attributable to preventable or treatable diseases such as diarrhea, lower respiratory infections, HIV/AIDS, tuberculosis, and malaria. While significant advances have been made in interventions to prevent and treat most of these diseases, those interventions are often unavailable to the populations most in need.

 

The Response

Over the past century, the public health community has enjoyed periodic major successes in the control and elimination of infectious diseases.

Annual Deaths (in millions)

Disease Deaths
Respiratory Infections 3.9
Malaria 1.3 - 3.0
HIV/AIDS 2.5
Diarrheal Diseases 1.8
Tuberculosis 1.7
Neglected Tropical Diseases 0.5

In one of public health's greatest victories, smallpox was eradicated in 1977. The smallpox effort was aided by committed medical and political leadership, an inexpensive vaccine that was relatively simple to administer, and a strong surveillance system that allowed rapid detection and containment of outbreaks.

Between 2000 and 2006, global measles incidence decreased by 91%, and incidence of Chagas Disease in Latin America decreased by over 70% from 1983 to 2000. More recently, the effort to eradicate Guinea worm (dracunculiasis) has accelerated and is now close to completion.

However, the global polio eradication program, intended for completion by 2000, has fallen victim to political and civil unrest in Nigeria, Afghanistan, Pakistan and India.

Vaccine Preventable Diseases

Vaccines play a critical role in reducing childhood mortality with an estimated 7.5 million lives saved over the last ten years.

Increased routine vaccination for measles, bacterial meningitis, tetanus, diphtheria, polio, pertussis, yellow fever and rotavirus greatly improved with better coordination, discrete budget sources and additional outside funding from groups like the Global Alliance for Vaccines and Immunization (GAVI). For newly introduced vaccines and old, efforts must focus on further increasing routine coverage of immunization through the broad array of strategies that have proved themselves successful, including targeted community campaigns, child health days and immunization weeks.

Diarrhea and respiratory infections are the two most common causes of pediatric deaths. Infectious diseases can also impair physical and mental development among survivors. Malaria during pregnancy can result in low-birthweight babies and cognitive defects. Parasitic infections can lead to malnutrition, stunted growth and chronic pain.

World Health Organization, The Global Burden of Disease 2004 Update, Geneva: 2009

HIV/AIDS

An estimated 33 million people are living with HIV today with a further 2.7 million new HIV infections occurring annually.

HIV is transmitted through direct contact with infected blood, semen, vaginal secretions or through mother-to-child transmission. Prevention programs that teach safer sex and use of clean needles and that provide anti-retroviral drugs for prevention of mother-to-child transmission can dramatically reduce new infections.  

For those already infected, antiretroviral therapy (ART) can manage the disease by prolonging and improving quality of life, but it is not a cure. Access to ART has been improving and currently roughly 3 million HIV infected people are receiving ART, while another 9.7 million people remain in need .

Tuberculosis (TB)

Worldwide an estimated 13.7 million people are infected with active, infectious TB, while almost 2 billion (nearly 1/3rd of the world's population) are infected with the TB bacillus. In recent years, the significance of the disease has increased significantly.

TB is the major cause of death among people with AIDS. In addition, new drug-resistant strains of TB have emerged that are difficult to treat successfully. The extremely resistant drug strain (XDR-TB), is fatal in a large proportion of cases. TB treatment depends on a strategy of rapid detection by sputum smear or x-ray followed by quick provision of directly observed multi-drug therapy for six months (commonly called direct observed treatment, short course (DOTS)).

Malaria

After a failed global eradication program in the 1960s and 1970s, the world has made significant gains against malaria in recent years. Incidence has been reduced by 2/3 in some African countries that have adopted a combination of measures including the spraying of insecticides and the introduction of insecticide treated bed nets (ITNs).

In addition, the use of antimalarial drugs like artemisinin has had the dual benefit of curing the infection and reducing the blood parasite reservoir that allows further spread of the disease. Despite progress, an estimated 247 million people are affected by malaria each year with the heaviest mortality concentrated in children under the age of 5.

For many of these diseases, especially HIV/AIDS, tuberculosis and malaria, drug resistance is an ever-present concern and access to effective vaccines is still many years away.

 

Opportunities for U.S Engagement

U.S. foreign assistance for infectious disease has taken many different forms. From the creation of the U.S. Public Health Service in 1798 to the multi-billion dollar programs today, public health programs cut across departments and agencies. While some diseases like HIV/AIDS and malaria have their own specific control programs, the President's Emergency Plan for AIDS Relief (PEPFAR) and the President's Malaria Initiative, others are part of larger programs at USAID, CDC and the NIH.

Even though the U.S. is currently the largest donor to global health programs there are still many opportunities for new or increased U.S. engagement -- from supporting critical research and development for new drugs, vaccines and diagnostics, where the U.S. is already the leading government funder, to developing improved models for disease surveillance, drug procurement/delivery and program management and evaluation.