Prefi biostat lesson 3

I. Prevention of Infectious Diseases

II. Overview of Infectious Disease

Historical Context

  • Humans have coexisted with microbes throughout history.

  • Notable figure: John Snow, who laid foundations for infectious disease epidemiology by analyzing and controlling cholera (Vibrio cholerae).

Factors Influencing Immunity

  • Genetic Background: Individual susceptibility to infection.

  • Overall Health: Presence of pre-existing health conditions.

  • Sanitation and Nutrition: Access to clean living conditions and healthy food.

  • Social Status and Poverty: Impacts infectious disease transmission.

    • Poverty can create environments conducive to disease spread.

Causal Pathways for Infectious Diseases

  • Physical Environmental Factors: Health risks during pregnancy, sanitation issues.

  • Genetic and Biological Factors: Microbial characteristics affecting infectivity, e.g., stability and infectious dose.

  • Repeated Diarrheal Episodes: Negative impact on child development.

  • Ecological Factors: Interaction with microbes through environmental factors.

  • Social, Political, and Economic Factors: Affect disease prevalence and health outcomes.

III. Integrating Skills for Infectious Disease Control

  • Data Gathering: Acquiring history related to sensitive topics like sexual behaviors.

  • Epidemiological Mapping: Geographic analysis to determine outbreak sources.

  • Outreach: Engaging with the public and health professionals to promote preventive measures.

  • Preventive Screening and Tracing: Screening at-risk populations and tracing contacts of infected individuals.

IV. Public Health Prevention Strategies

  • Improving Host Resistance: Vaccination, post-exposure prophylaxis, chemoprophylaxis.

  • Environmental Safety: Enhancing sanitation, monitoring air and water quality, vector control.

  • Public Health System Improvements: Better education, disease containment strategies, building herd immunity.

V. Four Domains of Human-Microbe Interaction

1. Genetic and Biological Factors

  • Human Susceptibility: Genetics and immunity to infections.

  • Microbial Characteristics: Affecting prevalence and infectivity.

  • Nutrition & Vaccines: Essential for decreasing susceptibility.

2. Physical Environment Factors

  • Impact of Climate: Effects on transmission and survival of pathogens.

  • Natural Disasters: May lead to spread due to overcrowding and sanitation issues.

3. Ecological Factors

  • Transmission Pathways: Water, soil, air, food contact.

  • Emerging Infectious Diseases: Animal reservoir interactions highlight importance of habitat preservation.

4. Social, Political, and Economic Factors

  • Human Behavior: Impact on disease spread with international interaction.

  • Income Inequality: Heightens vulnerability to diseases.

VI. Burden of Disease

Trends in Infectious Disease

  • Infectious disease mortality decreased in the U.S. since 1900 due to antibiotics and vaccines, later fluctuated in the 1980s due to re-emerging infections.

  • Low-income countries experience significant infectious disease burden.

Global Disease Impact (DALY)

  • 5 of the 10 leading causes of global disease burden are infections, including:

    • HIV/AIDS

    • Lower respiratory infections

    • Diarrheal diseases

    • Malaria

    • Tuberculosis

VII. Accurate History for Disease Management

  • Importance of behavioral history-taking in identifying infectious disease risk.

  • Techniques for discussing sensitive subjects depend on patient age, ensuring confidentiality.

  • Model "5Ps" for discussion: Partners, Prevention, Protection, Practices, Past infections.

VIII. Disease Transmission Modes and Control Measures

Contact-Based Transmission

  • Control measures include practicing hygiene, isolation, and early treatment.

  • Examples of diseases include:

    • Respiratory infections (e.g., influenza, meningitis)

    • STDs (e.g., HIV, syphilis)

IX. Public Health Priorities: HIV/AIDS, Tuberculosis, and Malaria

Epidemiology

  • Major causes of deaths in sub-Saharan Africa and globally.

  • Global Fund initiatives target these three infections through a collaborative approach.

HIV Data

  • Disparities in infection rates and mortality across regions.

  • Prevention methods: Emphasizing safe practices like monogamous relationships, use of condoms, and needle sharing avoidance.

X. Tuberculosis (TB) Overview

Historical Trends

  • Decline in TB incidence until the 1980s; resurgence due to drug resistance.

  • Classification of multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB).

TB Prevention

  • Strategies include BCG vaccination and Directly Observed Therapy, Short Course (DOTS).

XI. Malaria Epidemiology and Prevention

Disease Impact

  • In 2009, 225 million cases and approximately 781,000 deaths, predominantly among children.

  • Primary transmission vector: Female Anopheles mosquitoes.

Prevention Strategies

  • Use of insecticide-treated mosquito nets and indoor residential spraying.

  • Immediate treatment of diagnosed cases to reduce resistance.

XII. Emerging Threats: Antimicrobial Resistance

Challenges in Healthcare

  • Health care-associated infections (HAI) prevalent when patient's defenses are compromised.

  • Need for effective infection control protocols.

Antimicrobial Resistance Prevention

  • Employing narrow-spectrum antibiotics only as necessary, following strict infection control protocols.

XIII. Conclusion: Ongoing Need for Vigilance

  • Need for continued investment in public health infrastructure to identify and manage emerging infections globally.

  • Importance of community involvement and preventive strategies in mitigating disease spread.