In 1854 England, a cholera epidemic started wiping out people within a day of symptoms starting. Only one physician, Dr John Snow, thought that it connected with contaminated water sources. Over the course of a month, Dr Snow was able to provide evidence that one particular well was connected with almost all of the deaths. Later, it was discovered that the contaminant in the water was a bacterium, named for the disease it caused, Vibrio cholerae. Unfortunately, cholera is not a disease of the past. The World Health Organization calculates an average of 1.3-4 million cases where an estimated 21-143,000 of these cases result in death. In some places, there is enough preventative testing to stop the spread of the disease before people get sick. However, in others, the contamination is unfortunately addressed only after an epidemic occurs.
- 15.1: Types of Environmental Hazards
- Environmental health focuses on how natural and human-built surroundings affect health and well-being. This field assesses three interrelated types of environmental hazards: biological, chemical, and physical.
- 15.2: Epidemiology
- The field of epidemiology is concerned with the geographical distribution and timing of infectious disease occurrences and how they are transmitted and maintained in nature, with the goal of recognizing and controlling outbreaks. The science of epidemiology includes etiology (the study of the causes of disease) and investigation of disease transmission (mechanisms by which a disease is spread).
- 15.3: Infectious Diseases
- Infectious diseases remain a leading cause of death worldwide. Emerging diseases are those that have increased in prevalence in the last 20 years. Key infectious diseases of global concern are COVID-19, Ebola virus disease, HIV/AIDS, malaria, and tuberculosis. Many diseases have been eradicated with the help of vaccinations, but some diseases for which vaccines exist remain a threat. Antibiotics are effective in treating infectious diseases, but widespread use causes antibiotic resistance.
- 15.4: Environmental Toxicology
- Environmental toxicology is the scientific study of the health effects associated with exposure to toxic chemicals. Potency, persistence, solubility, bioaccumulation, and biomagnification can all impact the safety of a chemical. The dose-response curve can determine the lethal dose-50%, a measure of toxicity.
- 15.5: Environmental Hazard Reduction
- The World Heath Organization works with the CDC in the U.S. and equivalent agencies in other nations to promote global public health. Key strategies for reducing environmental hazards include providing access to clean water, improving sanitation and hygiene, and limiting exposure to disease vectors. The public serves an important role by engaging in behaviors that limit disease spread or exposure to toxins and supporting policies that limit environmental hazards.
Modified by Rachel Schleiger (CC-BY-NC).