Adaptation to Biological Stressors: Diseases

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Questions and Answers

What did the miasma theory suggest was the cause of disease?

Poor sanitation practices

Poisonous vapor from decaying matter (correct)

Microorganisms in the air

Genetic predisposition

Which individual is noted for establishing the germ theory of disease?

Edward Jenner

Robert Koch

Louis Pasteur (correct)

Joseph Lister

How did urbanization during the Middle Ages contribute to health issues?

Improved nutrition availability

Concentration of waste leading to bad smells (correct)

Reduced exposure to pathogens

Increased access to vaccines

What is a modern example of a disease caused by bacteria in specific environments?

Legionnaire’s disease linked to air conditioning systems Signup and view all the answers

What impact did social stratification have on disease risk in preindustrial cities?

Disparities in illness and death due to access to nutrition and care Signup and view all the answers

What is the primary vector responsible for the transmission of malaria?

Anopheles mosquitoes Signup and view all the answers

Which of the following is a characteristic symptom of Ebola Virus Disease?

High fever and rash Signup and view all the answers

What is the method of transmission for Ebola Virus Disease?

Direct contact with bodily fluids Signup and view all the answers

Which of the following adaptations provides some resistance against malaria?

Sickle cell trait (HbS) Signup and view all the answers

What is the fatality rate range for Ebola Virus Disease?

25%-90% Signup and view all the answers

What type of treatment is administered for severe cases of Ebola Virus Disease?

Rehydration therapy Signup and view all the answers

Which vaccines have been developed for Ebola Virus Disease?

One approved, targeting a specific virus Signup and view all the answers

What was a significant historical outbreak of Ebola Virus Disease?

First outbreak in Central Africa in 1976 Signup and view all the answers

What primary function does HIV have in the human body?

Destroys immune cells Signup and view all the answers

What is the role of the Chemokine receptor 5 (CCR5) in relation to HIV?

It allows HIV to bind to T cells Signup and view all the answers

Which variant of the CCR5 receptor provides resistance to certain strains of HIV-1?

CCR5-Δ32 Signup and view all the answers

Which treatment option is used to reduce the risk of HIV infection before exposure?

Pre-exposure Prophylaxis (PrEP) Signup and view all the answers

How does cholera primarily spread among communities?

Water contaminations Signup and view all the answers

What is a common consequence of cholera infection?

Dehydration Signup and view all the answers

Which blood type is more susceptible to cholera infection?

Type O Signup and view all the answers

What is the primary purpose of Anti-retroviral therapy (ART) in HIV treatment?

To reduce viral load to undetectable levels Signup and view all the answers

What is the primary focus of the epidemiological transition model?

Shifts in disease patterns over the past 10,000 years Signup and view all the answers

Which age of epidemiological transition is characterized by the emergence of infectious and nutritional diseases?

Age of pestilence and famine Signup and view all the answers

What significant event is linked to the Age of Receding Pandemics?

The Industrial Revolution Signup and view all the answers

Which type of diseases have emerged due to increasing microbial resistance?

Novel diseases Signup and view all the answers

What major change contributed to the rise of communicable diseases during the Neolithic period?

Increase in population density Signup and view all the answers

What factors contributed to the emergence of diseases in preindustrial cities?

High population density and stored food Signup and view all the answers

Which of the following was a significant factor in the spread of waterborne diseases in ancient urban settings?

Contamination of food and water Signup and view all the answers

Zoonoses, which are diseases that can be transmitted from animals to humans, were particularly influenced by which of the following?

Urbanization and agricultural practices Signup and view all the answers

Study Notes

Adaptation to Biological Stressors: Infectious Disease

This presentation covers infectious diseases, including malnutrition, human adaptations, epidemiological transitions, historical disease contexts, and modern city disease/culture.

Introduction

Malnutrition
Infectious diseases
- Humans, disease, and adaptations
- Epidemiological Transition
- History of disease
- Modern cities, disease, and culture

1. Humans and Disease

Co-evolving for thousands of years
Have we adapted?
- Yes
- No
- Somewhat

Infectious Diseases

Vector-borne diseases
- Malaria (Plasmodium falciparium, Anopheles mosquitoes, human and mosquito reproductive cycles)
Direct-contact diseases
- Ebola
Intimate-contact diseases
- HIV
Poor sanitation diseases
- Cholera

Malaria Adaptations

Hb variants
- HbS: Sickle cell trait
- Thalassemia
- G6PD deficiency

Ebola Virus Disease (EVD)

Direct-contact/Zoonosis
- Highly virulent in humans
  - Pathogen's ability to infect/damage a host
Fruit bats are natural hosts
- Close contact (blood, secretions, organs) with infected animals leads to spread
Monkeys and apes
- Human-to-human transmission via direct contact

Ebola Virus Ecology and Transmission

Animal-to-animal transmission involves bats
Spillover events occur when animals/humans are infected
Human-to-human transmission through blood and body fluids from sick or deceased individuals

Ebola Virus Disease (EVD): Symptoms

Symptoms include fever, fatigue, muscle pain, headache, sore throat, vomiting, diarrhea, rash, and impaired kidney/liver function
Both internal/external bleeding can occur in some cases
Transmitted via contact with bodily secretions
50% fatality rate (25-90% range)
First outbreak in Central Africa (1976)

EVD: Treatment and Adaptations

Rehydration with oral/IV fluids
Monoclonal antibody treatments
Bind to virus proteins like natural antibodies
RCTs during the 2018-2020 outbreak in DRC
Vaccine (one approved, effective against one virus)
Population-specific adaptations (future considerations)

HIV: Intimate-Contact Disease

Human Immunodeficiency Virus
Weakens immune system
Destroys CD4 (T) cells
Harder to fight infections/cancer
Originated in West Africa from chimpanzees and sooty mangabeys
Existed in the U.S. during the mid-to-late 1970s

HIV Adaptations

Varying degrees of resistance (some live 20+ years, some die within a year)
Chemokine receptor 5 (CCR5)
- Allows HIV to enter cells
CCR5-432 variant (mutation)
Lack of receptors
- Homozygous carriers resistant to certain HIV strains

HIV Treatment

Antiretroviral therapy (ART)
- Can reduce viral load to undetectable levels
  - Prevents or reduces transmission if undetectable
Pre-exposure prophylaxis (PrEP)
- Reduces risk of infection
Post-exposure prophylaxis (PEP)
- Taken within 72 hours of exposure

Cholera

Poor sanitation
Water-borne disease
Vibrio cholerae (fecal contamination)
Symptoms
- Dehydration, diarrhea, and vomiting
2.9 million cases, 95,000 deaths yearly, 10% severe symptoms can die in hours
Variation in susceptibility (Type O more susceptible)
Hyperactivation of key intestinal signaling molecules causing inflammation
Excretion of electrolytes and water

Cholera Adaptations

Variation in susceptibility
- Type O blood more susceptible
Lack of A or B antigens
Hyperactivates a signaling molecule, leading to inflammation, electrolyte/water excretion.

Malnutrition & Infectious Disease

Under-nutrition linked to infections
Poverty affects food security, access to healthcare, and living conditions
These create higher pathogen loads and enteropathy (enteric disease). Non-immunological factors like respiratory muscles, dehydration, and cardiac functions are impacted by these conditions.

2. Epidemiological Transition

Explains shifts in disease patterns over the past 10,000 years
Abdel Omran (1971) - How patterns of mortality change
Disease burden shifted from infectious to chronic illnesses (communicable to non-communicable)
Ongoing issue in low and middle-income countries

Epidemiological Transition - Now/Future

Age of pestilence & famine
- Emergence of infectious and nutritional diseases
Age of receding pandemics
- Industrial Revolution
Age of chronic and man-made diseases
- “Degenerative disease” (late 20th century)
Novel diseases (re-emergent infections)
- Increasing microbial resistance (antibiotic resistance)
- Increasing zoonotic diseases
- Rapid spread due to globalization

3. Diseases of the Past

Hunting-gathering/foraging prior to 10,000 years ago
- Small populations, temporary settlements
- Diseases of exposure/parasites/zoonoses
~10,000 years ago (Neolithic)
- Agriculture
- Increased population densities
- Sanitation issues
Preindustrial cities (~3000 BCE)
- Very high densities
- Food/water contamination, sewage
- Typhoid fever, cholera, etc.

Communicable Diseases of the Past

Originated from animal viruses (measles, rubella, mumps, chicken pox, smallpox)
Sweep through populations every few years
Children not previously exposed susceptible

Modern Cities, Disease, and Culture

Culture influences relationships with physical & biological environments
Modern city challenges
Legionnaire's disease (pneumonia-like symptoms, Legionella bacteria, AC ducts, hot tubs)

Next Steps: Disease Warriors (2006)

Work of early researchers to understand & fight disease
Vaccines (past, present, future)

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Description

This quiz explores the adaptations humans have made in response to infectious diseases. It covers topics from malnutrition to the epidemiological transitions and the historical context of diseases. Additionally, it discusses specific diseases like malaria and Ebola, and their impacts on human evolution.