Learning objectives
Learning Objectives
By the end of this section, you will be able to:
- Describe the entities involved in international public health and their activities
- Identify and differentiate between emerging and reemerging infectious diseases
A large number of international programs and agencies are involved in efforts to promote global public health. Among their goals are developing infrastructure in health care, public sanitation, and public health capacity; monitoring infectious disease occurrences around the world; coordinating communications between national public health agencies in various countries; and coordinating international responses to major health crises. In large part, these international efforts are necessary because disease-causing microorganisms know no national boundaries.
The World Health Organization (WHO)
International public health issues are coordinated by the World Health Organization (WHO), an agency of the United Nations. Of its roughly $4 billion budget for 2015–16World Health Organization. “Programme Budget 2014–2015.” http://www.who.int/about/finances-accountability/budget/en., about $1 billion was funded by member states and the remaining $3 billion by voluntary contributions. In addition to monitoring and reporting on infectious disease, WHO also develops and implements strategies for their control and prevention. WHO has had a number of successful international public health campaigns. For example, its vaccination program against smallpox, begun in the mid-1960s, resulted in the global eradication of the disease by 1980. WHO continues to be involved in infectious disease control, primarily in the developing world, with programs targeting malaria, HIV/AIDS, and tuberculosis, among others. It also runs programs to reduce illness and mortality that occur as a result of violence, accidents, lifestyle-associated illnesses such as diabetes, and poor health-care infrastructure.
WHO maintains a global alert and response system that coordinates information from member nations. In the event of a public health emergency or epidemic, it provides logistical support and coordinates international response to the emergency. The United States contributes to this effort through the CDC. The CDC carries out international monitoring and public health efforts, mainly in the service of protecting US public health in an increasingly connected world. Similarly, the European Union maintains a Health Security Committee that monitors disease outbreaks within its member countries and internationally, coordinating with WHO.
Emerging and Reemerging Infectious Diseases
Both WHO and some national public health agencies such as the CDC monitor and prepare for emerging infectious diseases. An emerging infectious disease is either new to the human population or has shown an increase in prevalence in the previous twenty years. Whether the disease is new or conditions have changed to cause an increase in frequency, its status as emerging implies the need to apply resources to understand and control its growing impact.
Emerging diseases may change their frequency gradually over time, or they may experience sudden epidemic growth. The importance of vigilance was made clear during the Ebola hemorrhagic fever epidemic in western Africa through 2014–2015. Although health experts had been aware of the Ebola virus since the 1970s, an outbreak on such a large scale had never happened before (OSC_Microbio_16_04_SFTS). Previous human epidemics had been small, isolated, and contained. Indeed, the gorilla and chimpanzee populations of western Africa had suffered far worse from Ebola than the human population. The pattern of small isolated human epidemics changed in 2014. Its high transmission rate, coupled with cultural practices for treatment of the dead and perhaps its emergence in an urban setting, caused the disease to spread rapidly, and thousands of people died. The international public health community responded with a large emergency effort to treat patients and contain the epidemic.
Emerging diseases are found in all countries, both developed and developing (fs-id1167662775763). Some nations are better equipped to deal with them. National and international public health agencies watch for epidemics like the Ebola outbreak in developing countries because those countries rarely have the health-care infrastructure and expertise to deal with large outbreaks effectively. Even with the support of international agencies, the systems in western Africa struggled to identify and care for the sick and control spread. In addition to the altruistic goal of saving lives and assisting nations lacking in resources, the global nature of transportation means that an outbreak anywhere can spread quickly to every corner of the planet. Managing an epidemic in one location—its source—is far easier than fighting it on many fronts.
Ebola is not the only disease that needs to be monitored in the global environment. In 2015, WHO set priorities on several emerging diseases that had a high probability of causing epidemics and that were poorly understood (and thus urgently required research and development efforts).
A reemerging infectious disease is a disease that is increasing in frequency after a previous period of decline. Its reemergence may be a result of changing conditions or old prevention regimes that are no longer working. Examples of such diseases are drug-resistant forms of tuberculosis, bacterial pneumonia, and malaria. Drug-resistant strains of the bacteria causing gonorrhea and syphilis are also becoming more widespread, raising concerns of untreatable infections.
View original figure (external; image not reproduced in this text edition)
Original figure description: Graph of Known human cases of Ebola virus diseases worldwide from 1976 – 2015. There were 604 in 1976-77. There were 44 in 1978-79. There were 0 from 1980 – 87. There were 3 in 1988-89. There were 4 in 1990-91. There were 368 in 1994-95. There were 100 in 1996-97. There were 0 in 1998-99. There were 547 in 2000-2001. There were 178 in 2002-2003. There were 18 in 2004-2005. There were 413 in 2006-2007. There were 38 in 2006-2007. There were 38 in 2008-2009. There was 1 in 2010-2011. There were 53 in 2012-2013. There were 28,718 in 2014-2015.
| Some Emerging and Reemerging Infectious Diseases | ||||
|---|---|---|---|---|
| Disease | Pathogen | Year Discovered | Affected Regions | Transmission |
| AIDS | HIV | 1981 | Worldwide | Contact with infected body fluids |
| Chikungunya fever | Chikungunya virus | 1952 | Africa, Asia, India; spreading to Europe and the Americas | Mosquito-borne |
| Ebola virus disease | Ebola virus | 1976 | Central and Western Africa | Contact with infected body fluids |
| H1N1 Influenza (swine flu) | H1N1 virus | 2009 | Worldwide | Droplet transmission |
| Lyme disease | Borrelia burgdorferi bacterium | 1981 | Northern hemisphere | From mammal reservoirs to humans by tick vectors |
| West Nile virus disease | West Nile virus | 1937 | Africa, Australia, Canada to Venezuela, Europe, Middle East, Western Asia | Mosquito-borne |
Key Concepts and Summary
- The World Health Organization (WHO) is an agency of the United Nations that collects and analyzes data on disease occurrence from member nations. WHO also coordinates public health programs and responses to international health emergencies.
- Emerging diseases are those that are new to human populations or that have been increasing in the past two decades. Reemerging diseases are those that are making a resurgence in susceptible populations after previously having been controlled in some geographic areas.
Multiple Choice
Which of the following would NOT be considered an emerging disease?
- Ebola hemorrhagic fever
- West Nile virus fever/encephalitis
- Zika virus disease
- Tuberculosis
D
Which of the following would NOT be considered a reemerging disease?
- Drug-resistant tuberculosis
- Drug-resistant gonorrhea
- Malaria
- West Nile virus fever/encephalitis
D
Which of the following factors can lead to reemergence of a disease?
- A mutation that allows it to infect humans
- A period of decline in vaccination rates
- A change in disease reporting procedures
- Better education on the signs and symptoms of the disease
B
Why are emerging diseases with very few cases the focus of intense scrutiny?
- They tend to be more deadly
- They are increasing and therefore not controlled
- They naturally have higher transmission rates
- They occur more in developed countries
B
Fill in the Blank
The ________ collects data and conducts epidemiologic studies at the global level.
WHO (World Health Organization)
Critical Thinking
An Atlantic crossing by boat from England to New England took 60–80 days in the 18th century. In the late 19th century the voyage took less than a week. How do you think these time differences for travel might have impacted the spread of infectious diseases from Europe to the Americas, or vice versa?