Lecture on Pathogens, HIV, Antibiotics, and Vaccines

Overview of Pathogens

• Pathogens have greatly impacted societies throughout history.
• Key pathogen for IB exam: HIV (Human Immunodeficiency Virus).

HIV and AIDS

• HIV:
  • Targets and kills T cells, affecting the immune system.
  • Leads to a decrease in T cells, causing acute HIV syndrome.
  • Goes dormant (clinical latency) and can reactivate, leading to AIDS.
  • Transmits via unprotected sex, pregnancy, sharing needles, medical exposure, and transfusions.
• AIDS (Acquired Immunodeficiency Syndrome):
  • Third stage of HIV, body becomes vulnerable to other pathogens.
  • Opportunistic infections become lethal due to weak immune system.

Antibiotics

• Function: Kill/inhibit bacterial growth by targeting prokaryotic metabolism.
• Penicillin:
  • Discovered by Alexander Fleming in 1928.
  • Tested by Ernst Chain and Howard Flory, successfully treated bacterial infections.
• Limitations:
  • Ineffective against viral infections.
  • Overuse leads to antibiotic resistance among bacteria.
  • Bacteria with resistance make treatment difficult.
• Current Strategies:
  • Use antibiotics properly to maintain effectiveness.
  • Discover new antibiotics through chemical libraries.

Zoonotic Infections

• Zoonosis: Pathogens transferring between species.
• Important Zoonotic Diseases:
  • Tuberculosis (bacterial): Transmits through cattle, affects lungs.
  • Rabies (viral): Transmitted via animal bites, affects brain/spinal cord.
  • Japanese Encephalitis (viral): Mosquito-borne, causes brain inflammation.
  • COVID-19 (viral): Likely zoonotic, severe respiratory issues.

Vaccines

• Function: Activate adaptive immunity without active pathogen.
  • Types: Inactive pathogens, antigens, DNA/RNA for antigen creation.
• Importance:
  • Critical for viral protection as antibiotics are ineffective.
  • Contribute to herd immunity.
• Herd Immunity: Reducing disease transmission once population immunity reaches a threshold.

Evaluating Data

• Important in understanding disease spread and vaccine effectiveness.
• Percent Difference: Used for comparing similar datasets.
• Percent Change: Used for comparing datasets over time.
• Example Calculations:
  • Herd immunity population requirements for diseases, percent difference and change calculations demonstrated.

Conclusion

• Understanding pathogens, antibiotics, and vaccines is crucial for IB exams.
• Proper usage and understanding of medical data are essential for infectious disease management.