Lecture notes 12 November 2013 Symbiosis often means living together occurs between counless organisms 3 different types mutualism one deemed host one deemed symbiant both host and symbiant organism benefit host give place for symbiant to replicate nutrients protection from pathogens symbiant provides something to the host for example help us digest food 2g day source of protein for us example cow rumen commensalism usually the host provides an environment where the symbiant can replicate and grow but the symbiant doesn t provide any known benefits for the host parasitism when the host provides a place for the symbiant to grow but the host is getting detrimental effects because of the symbiant see slide chart Normal microbiota in hosts flora indigenous microbiota organisms that colonize the body s surfaces without normally causing disease also termed 2 types resident microbiota normal microbiota mostly commensal but maybe we haven t figured out what s going on transient microbiota could be normal but also could be pathogenic remain in the body for short periods found in the same regions as resident microbiota cannot persis in the body competition from other microorganisms elimination by the body s defense cells chemicals physical changes in the body see charts listen to his lecture for explanation of charts CLICKER 1 Why wash your hands with soap before eating A To remove pathogenic resident microflora B To remove transient microflora that could cause disease C To remove non pathogenic microflora D To remove the gram positive Aquisition of normal microbiota development in womb free of microorganisms microbiota begin to develop during birth resident microbiota establish in first months babies generally not exposed to microbiota in first months as baby moves down the vaginal canal it is rubbing against the epithelial skin picking up microbs breathing air picking up air microbes you cannot wash all microbes off your hands when you wash them then hold the baby babies put a lot of things in their mouths which leads to having the microbes into their intestines you may have similar microflora that your family has Opportunistic pathogens normal microbiota that cause disease conditions that provide opportunities for pathogens introduction of normal microbiota into unusual body site immune suppression changes in the normal microbiota changes in relative abundance may allow opportunity for a member to thrive and cause disease surface of your skin is different than below the surface of your skin blood nutrients water allow microbes to grow immune deficiency syndrome small infections can be a huge deal Changes in normal microbiota occurs because many reasons diet taking antibiotics etc Reserviors of infectious disease of humans pathogens tend to live in reserviors cannot survive outside their host generally thrive under conditions of their host reserviors of infections source where multiple people can be infected 3 kinds animal reserviors human carriers non living reserviors environment CLICKER 2 Zoonoses is a dead end for many pathogens because A Zoonitic pathogens are not evolved to live in humans B The method of transmission stops with humans C Some zoonotic pathogens kill human hosts D Contaiminated material is disposed of properly E All of the above Lecture notes 14 November 2013 started on slide biofilms Biofilms how to biofilms start see panapto lecture biofilms have an organized structure the organisms turn on certain genes when they organize themselves into a biofilm forms in situations where fluid is running by around them fluid has nutrients and they now have a better chance of absorbing the nutrients around them biofilms provide protection against phagocytosis antibiotics sometimes have difficulty diffusing into a biofilm Infectious disease invasion of the host by a pathogen you can be an a symptomatic carrier disease perterbs the normal coughing sneezing vomiting disease morbidity Host pathogen interactions death prevention methods human normal flora defenses non specific and specific treatments of disease to prevent microbe virulence factors way of destroying our cells to get at the nutrient center inside of us rapid growth large numbers synergies ex biofilm can work together to propogate growth when the human side is winning then we are healthy when the microbes are winning then we have disease Disease perturbation from normal link symptoms to causes treatment needs to fit disease some pathogens cause more than one disease plague slide bubonic septicemic fatal pneumonic fatal pharyngeal meningeal Manifestations of disease symptoms subjective characteristics of disease felt only by the patient signs objective manifestations of disease observed or measured by others syndrome symptoms and signs that characterize the disease or abnormal condition cause of the syndrome can be varied Stages of infection disease the disease proccess happens in the following way incubation period prodromal period illness decline convalescence CLICKER 1 At what point in the progress with an infectious disease could the victim get another person sick A incubation period B prodromal period C illness D decline E convalescence F all of the above G none of the above Virulence degree of pathogenicity abiltiy of the microorganism to cause disease adhesion factors biofilms extracellular enzyme CLICKER 2 What is a LD 50 A the minimum dose of chemical needed to kill people B the dose of chemical needed to kil 50 of a population C the dose of chemical that kills someone D I have no idea ID50 infectious dose how many microorganisms do you have to give someone before they get sick Extracellular enzymes secreted by pathogens dissolve chemical structures in the body outside of the bacterial cell helps pathogen maintain infection invade avoid body defenses important virulence of the pathogen mutant are a virulent Toxins harm tissues trigger immune responses causing damage continue after seeing slide Antiphagocytic factors factors prevent phagocytosis allow pathogens to remain in the host longer bacterial capsule composed of chemicals not recognized as foreign slippery and difficult for pathogens to engulf antiphagocytic prevent fusion of lysosome and phagocytic vesicles leukocidins directly destroy phagocytic white blood cells Movement of pathogens out of hosts portals of exit pathogens leave through portals of exit leave as secretions earwax blood flakes feces semen lubricating substances urine milk saliva tears