9.2 Technological Advancements and Limitations - Disease
Technological Advancements and Limitations - Disease
Introduction
Nathan Wolfe: We live in an era with the tools to build a global immune system.
Question: How have environmental factors affected human populations since 1900?
Overview of Progress
Progress in science and medicine, combined with government-run public health measures, drastically reduced illnesses and deaths from many diseases after 1900.
Pandemics: Epidemic diseases that spread across national borders.
Smallpox Elimination
Smallpox plagued ancient Egyptians and devastated native populations in the Americas and Australia.
As recently as the 1960s, it killed millions of people each year.
The World Health Organization (WHO) conducted a global vaccination campaign.
In 1979, scientists declared success: Smallpox had been eliminated from the planet, except for the culture kept at the Centers for Disease Control in the United States.
Persistent and Emerging Diseases
Other diseases persisted, especially those related to poverty, including malaria, tuberculosis, and cholera.
New epidemics emerged, such as particularly virulent strains of flu, HIV/AIDS, and Ebola.
Conditions like heart disease and Alzheimer's became more common as people began living longer.
Each new medical problem spurred even more technological and medical advances to combat it.
Disease and Poverty
Contributing Factors
Poor housing or working conditions, contaminated water, low incomes, and lack of access to health care contribute to the spread of disease.
Even when cures exist, some diseases persist because of poverty.
Malaria
A parasitic disease spread by mosquitoes in tropical areas.
Most of the more than 600,000 people who died each year in the early 21st century were young African children.
Doctors Without Borders (an NGO) treated about 1.7 million people annually.
Preventive approaches include mosquito nets treated with insecticide.
A vaccine for malaria has been in development for many years, but one that is effective in most cases is still in trials.
In 2019, the WHO certified Algeria and Argentina as malaria-free.
Caution: Some types of mosquitoes were becoming resistant to insecticides.
Tuberculosis (TB)
An airborne infection that spreads through coughs and sneezes and affects the lungs.
Before 1946, no effective drug treatment was available.
A cure was developed involving antibiotics and long periods of rest.
Vaccines are administered to children in countries where TB is common.
In the early 21st century, a strain of tuberculosis resistant to antibiotics appeared.
The number of infected patients increased, especially in prisons.
The WHO began a worldwide campaign against tuberculosis in the 2010s.
Cholera
A bacterial disease that spreads through contaminated water.
Causes about 95,000 deaths per year.
Affects mainly poor people in developing countries.
Methods to counter cholera include boiling or chlorinating drinking water and washing hands.
Cholera vaccines are available, but they do not reduce the need for preventive measures.
A severe cholera infection can kill within a few hours, but quickly rehydrating an exposed person can effectively eliminate the risk of death.
Causes of Death in Low-Income Countries (2016)
Top Causes
Lower respiratory infections (pneumonia, etc.)
Diarrheal diseases
Heart disease
HIV/AIDS
Stroke
Malaria
Tuberculosis
Causes of Death in Upper-Middle-Income Countries (2016)
Top Causes
Heart disease
Stroke
Chronic obstructive pulmonary disease
Trachea, bronchus, and lung cancers
Alzheimer’s disease and other dementias
Lung infections (pneumonia, etc.)
Diabetes mellitus
Liver cancer
Stomach cancer
Polio
Description
A disease caused by a virus transmitted in fecal matter, polio can result in paralysis and sometimes death.
Once infected 100,000 new people per year.
Vaccine Development
announced an injectable vaccine against polio in 1955.
developed an oral vaccine in 1961.
Global Campaign
Vaccines became the centerpiece of a global public health campaign to eliminate polio.
A joint effort by governments, private organizations, and United Nations agencies began in 1988.
Polio was eliminated in all but a few countries in less than 30 years.
Remaining Challenges
In places where it still exists, such as Pakistan and Afghanistan, war makes administering the vaccine difficult.
Political unrest and religious fundamentalism make people fearful of programs advocated by outsiders.
Success of Coordination
The success of the campaign showed that coordinated global efforts could help solve global problems.
Emerging Epidemics
Comparison to the Age of Exploration
Some diseases have emerged that caused major social disruption.
1918 Flu Pandemic
The Journal of the American Medical Association described the battle against the flu as medical science turning its full attention to combating the greatest enemy of all infectious diseases.
One-quarter of all Americans and one-fifth of the world's population became infected.
Killed 20 million people worldwide.
Victims tended to be between the ages of 20 and 40.
More people died from the flu in 1918-1919 than had died in four years of the Bubonic Plague (1347-1351).
Longevity in the United States fell by 10 years.
Like the plague, the flu spread along trade routes and with military troops.
HIV/AIDS
Another disease outbreak causing social disruption occurred between 1981 and 2014.
Acquired Immunodeficiency Syndrome (AIDS) is caused by the Human Immunodeficiency Virus (HIV).
Killed more than 25 million people around the world.
HIV weakens the immune system, making people more susceptible to other illnesses.
The virus is contracted through the exchange of bodily fluids, usually through unprotected sex, blood transfusions, or sharing intravenous needles.
Funding for research was difficult to come by initially because the disease was associated with homosexual men and drug addicts.
By the mid-1990s, medical researchers had developed antiretroviral drugs to treat the disease but not to cure it.
Antiretroviral drugs could stop HIV from weakening the immune system, allowing a patient to live with the virus for many years.
The drugs were very expensive, making access to treatment difficult, particularly for patients in poor countries.
Brazil established a policy of providing free antiretroviral drugs to any person who needed them in 1996.
Deaths have declined dramatically, and the program has saved the government money by lowering the number of hospitalizations, medical leaves, and early retirements.
After 2000, the WHO, the United States government, and private groups increased funding for AIDS prevention and treatment, but the disease remains a serious problem.
In 2018, about 40 million people globally were living with HIV, the majority in developing countries or low-income neighborhoods of developed countries.
Each week, more than 600 young women between the ages of 15 and 24 become infected with HIV, and many lack access to healthcare.
Ebola
Discovered in the Congo in 1976.
A deadly disease caused by a virus that infects the African fruit bat, humans, and other primates.
Humans get the virus through exposure to fluids of infected people or animals.
The disease causes extensive bleeding, organ failure, and for the majority of infected people, death.
In 2014, a massive outbreak in West Africa caused fear around the world.
A coordinated, intensive public health effort contained and then ended the outbreak.
Countries demonstrated their ability to work together to confront a danger.
The WHO took a leading role in this public health response, issuing emergency warnings and implementing a road map for handling the outbreaks.
Diseases Associated with Longevity
Heart Disease
As longevity increases, diseases that assert themselves later in life began to emerge as a growing concern.
One of the first series in fighting heart disease was the heart transplant performed by the South African Christiaan Barnard in 1967.
Other procedures include replacing valves, installing stents, and replacing arteries.
Researchers developed temporary devices, like the Jarvik-7 artificial heart, used as a temporary device while patients waited for a compatible human heart.
Developing medications to reduce blood pressure and cholesterol that led to heart disease.
In the 2000s, people with heart disease lived longer than similarly affected people did in the 1970s.
Alzheimer's Disease
As people lived longer, a form of dementia known as Alzheimer's disease that affects elderly and some middle-aged people became an increasing concern.
Alzheimer's patients progressively lose their memory, eventually leading to a stage in which they do not recognize their loved ones.
Since the disease undermines bodily functions, it leads to death.
Researchers continue to search for a cure.
Multiple Choice Questions
Tuberculosis Cases, 2015
Tuberculosis is an infectious bacterial disease that spreads through the air.
Question 1: Which of the following best explains the overall trend of tuberculosis cases shown on the map?
(A) The role of trade routes in spreading disease
(B) The lack of a global agency to coordinate public health campaigns
(C) The spread of diseases in countries with rising birth rates
(D) The persistence of diseases associated with poverty (Correct)
Question 2: Which of the following can be best be inferred about countries with lowest rates of tuberculosis infection?
(A) Climate conditions kill off the tuberculosis bacteria.
(B) Medical workers control the spread of tuberculosis with antibiotics. (Correct)
(C) Scientific advances have ended the threat of new epidemics.
(D) These countries receive the lowest numbers of immigrants cases.
Question 3: Which differences shown on the map most directly reflected a more general development in the late 20th century?
(A) Longer life expectancy (Correct)
(B) Deforestation and desertification
(C) Neocolonialism
(D) The uneven expansion of Internet access
Short-Answer Questions
Use the passage to answer all parts of the question: The health problems faced by the world's poorest populations are not caused by a lack of drugs specifically related to their problems and diseases. The real problem is ensuring that these populations can actually access vital medicines.
(A) Explain one action governments take, in Stevens's view, that keep people in need from accessing medications.
Governments impose punitive tariffs and taxes on medicines, restricting trade and raising costs.
(B) Explain ONE historical example that supports Stevens's argument.
The high cost of antiretroviral drugs for HIV/AIDS in poor countries, before generic versions became available, limited access to treatment.
(C) Explain ONE way in which environments have shaped societies between 1900 and the present.
Urban environments with poor sanitation and overcrowding fostered the spread of diseases like tuberculosis.
(D) Describe ONE example of a medical development that affected populations around the world between 1900 and the present.
The development and distribution of the polio vaccine led to the near-eradication of the disease worldwide.
Think as a Historian: Connect World War I and the Flu Epidemic
Explain how World War I relates to the flu epidemic of 1918-1919
The conditions of war, such as crowded military camps and troop movements, facilitated the rapid spread of the flu virus.
The war also diverted medical resources and attention away from public health, hindering efforts to control the epidemic.
Wartime censorship and propaganda may have downplayed the severity of the flu, delaying public health responses.
Reflect on the Topic Essential Question
Explain how environmental factors have affected human populations since 1900.
Environmental factors, including sanitation, access to clean water, and climate conditions, have significantly impacted human health and disease patterns.
Urbanization and industrialization have created new environmental challenges, such as pollution and overcrowding, which have contributed to the spread of certain diseases.
Climate change has altered ecosystems and disease vectors, leading to the emergence and spread of infectious diseases like malaria and dengue fever into new areas.