Ch.10.3-5 Epidemiology Microbiology

10.3 Predisposing Factors Anatomical-UTI Genetic-Cystic fibrosis Disease specific Climate & Weather Overall health Age Diet

10.3 Disease Development Stage 1: Incubation period Stage 2: Prodromal period Stage 3: Acute period Stage 4: Convalescence period

10.3 Disease Reservoirs Animals are natural reservoirs for many diseases Plague-rodents Chagas-armadillos Babeiosis-ticks Rabies-raccoons, skunks, bats Cholera-shellfish SARS-bats Ebola-bats, primates Human reservoir Non-living reservoir

10.3 Infectious Disease Transmission Direct contact Indirect contact Aerosolized-air Food & water contamination Fomite-objects Vector-animal carriers

10.3 Ecology, Epidemiology & Evolution of Pathogens Zoonose-disease transmitted between different species. Ecological competence- ability of a pathogen to survive and compete Virulence-the degree of pathogenicity, fatality rates.

10.3 Safety in the Microbiology Laboratory Center for Disease Control (CDC) biohazard levels 1-4 BSL1 Minimum risk, normal protection: gloves, goggles BSL 2 Bacteria & viruses that cause treatable disease, non- aerosol. Lab bench required BSL3 Severe to fatal diseases, but vaccines exist. Sealed containers with gloves, positive air flow. BSL 4 No vaccines or treatment, positive-pressure suit mandatory

10.3 Finding Patient Zero & Tracking Diseases Index case-patient zero Typhoid Mary-1900-1907 NYC Cook, infected 51 people, nearly 30 years of isolation HIV-1970’s Gaetan Dugas flight attendant. Later determined that he was one of several responsible. Ebola-2 year old boy in Guinea died 12/2/2013 bitten by a fruit bat

10.4 Microorganisms in the Hospital Hospital-acquired infections (HAI), nosocomial In U.S. 1.7 million/year, 99,000 deaths Ventilator-associated pneumonia UTI Staphylococcus aureus Methicillin resistant Staph. aureus (MRSA) Tuberculosis Legionnaires’ disease Hospital-acquired pneumonia (HAP)-most common cause of death

10.4 Chain of Transmission Gram-negative resistant bacteria can survive a long time on surfaces. Enter body through wounds and devices. Airborne: Legionella, TB, rubeola & varicella viruses. Poor sanitation practices by medical personnel is a major cause of infection. All medical personnel must follow proper sanitation protocols including: washing, sterilization and personal protection equipment (PPE).

10.5 Descriptive Epidemiology Calculation of risk factors based upon data; time, place & people. Age Education Socioeconomic status Availability of health services Race Gender Drug abuse Sexual promiscuity Diet Exercise

10.5 Analytical Epidemiology Statistical inferences based upon causes of disease in populations using sampling. Focuses on genetic and environmental factors that cause disease.

10.5 Experimental Epidemiology Uses an experimental model to confirm causal relationship suggested by observational studies. Three case types: Randomized control trial New medicine, drug testing Field trial High risk groups Community trial Social diseases

10.5 Public Health Local governmental programs to promote good health. Focus on prevention of disease. Hygiene Breastfeeding Diet Exercise Vaccination Planned parenthood Drug abuse rehabilitation

10.5 Global Health Epidemiological, medical, economic & political approaches. World Health Organization (WHO) UNICEF World Food Programme (WPF) United Nations (UN) World Bank Doctors Without Borders

10.5 Emerging and Reemerging Diseases Incidence increase in the last 20 years. 12% of all human pathogens. SARS HIV/AIDS Influenza West Nile Lyme disease Tuberculosis Ebola Zika

10.5 Biological Weapons Biological Warfare (BW) Banned by 1972 Biological Weapons Convention Smallpox Plague Tularemia Anthrax Brucellosis Botulism

10.5 Technology & New Infectious Agents Molecular Techniques are much faster and more accurate at identifying diseases. Treatment development and communication have accelerated. Overpopulation, industrial agriculture and ecosystem destruction are causing more diseases. Modern transportation greatly accelerates the scope and spread of diseases worldwide.

10.5 Current Pandemics Influenza 3 Pandemics in 20th century killed tens of millions 1918-1919 Spanish Flu 50-100 million deaths 1996-2008 Avian Flu (H5N1) 700 cases 60% mortality rate 2009-2010 Swine Flu (H1N1) 17,000 deaths HIV/AIDS 1981-today, about 70 million infected and 35 million dead Ebola 2013-2016, over 28,000 infected and 11,000 deaths Zika 2015-2016, 1.5 million infected, 3,500 microcephaly