4 Categories of Human Health Risk Risk is a measure of the likelihood that you will suffer harm from a hazard. Types of risk:Physical: environmental factors like natural disasters.Ex: tsunamis, UV exposure, climate changeBiological: risk associated with disease.HIV/AIDS, malaria, TB, obesityChemical: risk associated with exposure to chemicals, both natural occurring to synthetic chemicals like pesticides.DDT, PCB (synthetic) & arsenic, He, Pb (Natural occurring)Nicotine, caffeine, and other substances that are abused or recreationally used are included in this category.
5 Biological Risk: Disease Cause most of the human deaths.A disease is any impaired function of the body with a characteristic set of symptoms.Types of disease:Infectious disease – caused by infectious agents called pathogens (living organism). Ex: pneumonia & sexually transmittedPathogens that cause most infectious diseases are viruses, bacteria, fungi, protists, and parasitic worms.Top three infectious diseases:respiratory infections (TB, Flu, pneumonia)HIV/AIDSDiarrheal diseases
7 Biological Risk: Disease Non-transmissible disease:Diseases not caused by living organisms cannot spread from one person to anotherEx. Cancer, heart disease, cystic fibrosis~60% of deathsDisease is also categorized as:Chronic – slowly impair the body over time (decades)Heart disease & cancerAcute – rapidly impair the body (days or weeks)
8 Chronic DiseaseRisk factors of chronic disease is different for developing & developed countries:Developing country risk factors are associated with unsafe drinking water, poor sanitation, malnutrition.Developed country risk factors are less activity, poor nutrition, availability of tobacco, and overeating.
9 Obesity and poor air quality Malnutrition and sanitation
10 Biological Risk: Infectious Diseases Pathogens have evolved a wide variety of pathways for infection:Human to human (influenza, rhino virus)Animals to human (plague, malaria)Food to human (Botulism, mad cow)Water to human (Cholera, giardia)Epidemic – rapid increase in diseasePandemic – epidemic that occurs over a large geographic area (continent)
12 Biological Risk: Infectious Disease Plague (Black Death, Bubonic plague):Cause – bacterium (Yersinia pestis) carried by fleas of rodents.Transmitted by flea bite or handling of rodentsKilled hundreds of millions (one-fourth European population)Treatment – modern antibiotics
14 Biological Risk: Infectious Disease Malaria:Cause – protists from the genus Plasmodium. Transmitted to humans by mosquitos.Effect – Kills 1 million people/ yearSymptoms – re-current flu-like symptomsHardest hit are sub-Saharan Africa, Asia, Middle EastTreatment – spray mosquitos with insecticides like DDT (now banned globally)
16 Biological Risk: Infectious Disease Tuberculosis:Highly contagious!!Cause – Bacterium (Mycobacterium tuberculosis)Infects lungs and spreads by coughing (bacteria can live several hours)Effect - One third of the world population is infected with TBEach year 9 million are infected & 2 million dieTreatment – antibiotics if available.If antibiotics are stopped before all bacterium are killed, they become drug resistant
18 Emergent Infectious Diseases Defined as infectious that were previously not described for the prior 20 years
19 HIV/AIDS In 1970’s rare types of pneumonia and cancer began appearing. Cause: Human Immunodeficiency Virus (HIV)Spread through both sexual contact & sharing needlesSource found to be chimpanzees (from the eating of flesh)Effect: 25 million died from HIV/AIDSTreatment: antiviral drugs used maintain low levels of HIV in humansDrug cocktails are very expensive but governments and non-profits have greatly improved distribution in developing countries.
20 Ebola Hemorrhagic Fever Cause: Ebola virusFirst discovered in the CongoInfected humans & primatesEffect: Kills a large % of those infected (50 – 89% death rate) in two weeks.Treatment: there are no drugs available to fight virusOrigin remains unknown
22 Mad Cow DiseaseNeurological disease in which pathogen slowly destroys the hosts nervous system.Cause: prions (proteins in the brain of cattle that mutate and act as a pathogenDiscovered disease could be passed to humansCow must consume nervous system of infected cow to contract diseaseEffect: 180 k cattle infected & 166 people diedTreatment: outlaw the practice of feeding cows dead cow protein
24 Bird Flu 1918 Spanish flu (bird flu) killed 100 million people Cause: H1N1 virus & H5N1 virusH5N1 could potentially kill 150 millionRarely deadly to wild birdsNot easily passed among people but future mutation could change that
25 West Nile VirusLives in hundred of species of birds and is transmitted among birds by mosquitosFirst human to contract West Nile was in 1937Causes inflammation of the brain1999 virus appeared in New York