传染病学总论全英班.pptx

1 SINGNIFECANCE AND IMPORTANCE SINGNIFECANCE AND IMPORTANCE 2History reviewHistory reviewIn 14th century,Plague in European,20 million people death；In 1718th century,smallbox in European，150 million people death；In 1918,flu in the worldwide，40 million people death。3In 1905,Nobel gainer of In 1905,Nobel gainer of physiology and medicine award physiology and medicine award Robert Koch(Germany)Robert Koch(Germany)Koch discovered tubculosis bacilii4In 1945,Nobel gainer of In 1945,Nobel gainer of physiology and medicine awardphysiology and medicine award Alexander Fleming(Scotland)Alexander Fleming(Scotland)In 1928年，年，FlemingDiscorvered PenicillinInto antibiotics era5WHO reports：Among 52 million of death in the worldwide annually,17 million(32%)of death from infectious diseases and parasiteIn developing country，a half of death by infectious diseases；About 15 million of death by infectious diseases per hour in the worldwide，most occurred in developing country。6Pattern of Infection in Developed CountriesIn 20th century,fall in the incidence of communicable diseases in developed countriesdue to factors such as:Immunizationantimicrobial chemotherapyimproved nutritionand better sanitation and housing.7Re-emergence of old infectious disease(Tuberculosis)(Tuberculosis)(Viral hepatitis)(Viral hepatitis)(Sexually transmitted diseases)(Sexually transmitted diseases)others:others:choleracholera、charcoalcharcoal8Re-emergence of old infectious disease2 million death of TB in the worldwide annually78 million infected by TB in the worldwide annuallyMarch 24,for World TB Day9Emerging infectious diseasesEmerging infectious diseases WHO information near 30 years,about 30 kinds of infectious diseases discovered in the worldwide“Emerging infectious diseases”10Emerging infectious diseasesEmerging infectious diseases40 million of HIV/AIDS cases worldwideHIV infection rates:11 cases/minute 16000persons/per day 6 million persons/annually。95%in developing countryMaximal nation:Africa,infection rate about 10%Dec.1 forDec.1 for World AIDS DayWorld AIDS Day 11Emerging infectious diseasesEmerging infectious diseasesSARS（SARSCoV）From 2002.11.16 to 2003.7，SARS spreaded 6 continent,32 countries，cases of 8437，death of 916In china,cases of 5327，death of 349 SARS:most serious emerging infectious diseases in 21 century12Emerging infectious diseasesEmerging infectious diseasesAvian influenza H5N1 virus H1N1 VIRUS13AntibioticsAntibiotics,within the last 60 years,Resulted in the cure of many previously lethal infectionsOnly several years,drug-resistant emerged.pathogenic staphylococci were found to have the ability to produce enzymes(penicillinases)that destroyed penicillin,thus rendering the drug useless against these strainsOveruse and misuse make them useless.14COMMUNICABLE DISEASESINFECTION AND IMMUNITYPATHOGENESISEPIDEMIOLOGYDIAGLOSIS TREATMENT PROVENTION PROFILE 15 CONCEPT OF COMMUNICABLE DISEASESCaused by pathogens:virus、chlamydia、richettsia、prion、bacteria、spirochete、fungus and parasite（helminth、protozoa）or medical insectInfectious disease:involve any organ or system of the body and thus embraces all medical disciplines.Communicability which differentiates infections from non-infectious diseases.Transmission of pathogenic organisms to other people,directly or indirectly,may lead to an epidemic.16 Infection and immunity 17一一.Concept of infection.Concept of infectionThe course of struggle between pathogens The course of struggle between pathogens and human or animal bodies(host).and human or animal bodies(host).Absolutely necessary conditionAbsolutely necessary condition18Commensalsopportunistic infectionPrimary infectionPrimary infectionRepeated infectionRepeated infectionMixed infectionMixed infectionSuperinfectionSuperinfectionSecondary infectionSecondary infectionKinds of infections 19Commensalism Pathogens live in the host but dont induce pathologic changes.Escherichia coli in the colon Epstein-Barr virus20Opportunistic infection:Pathogens within the host can induce pathologic changes if host immunity is suppressed by some factors.Cryptococcus neoformans Cytomegalovirus Candida albicans21Primary infection:measles,chicken boxRepeated infection:malaria,schistosomiasis,ancylostomiasisMixed infection:rareSuperinfection:HBV overlap HEVSecondary infection:HBV following bacilli22Eliminate pathogenEliminate pathogeninapparent/sub-clinical infectioninapparent/sub-clinical infectionapparent/clinical infectionapparent/clinical infectionCarrier statusCarrier statusLatent infectionLatent infectionInfections status（infection spectrum）Entrance and colonization of pathogens will lead to the following results 23 Elimination:Elimination:pathogens were excluded out by host pathogens were excluded out by host nonspecific or specific immunity.nonspecific or specific immunity.Such as:Candida albicans Such as:Candida albicans Hepatitis A virus Hepatitis A virus24 inapparent/sub-clinical inapparent/sub-clinical infection:infection:most frequently occurs in most frequently occurs in healthy individuals.healthy individuals.The outcomes will be:The outcomes will be:A.Immunity acquired.HAV A.Immunity acquired.HAV B.Carrier state:healthy carriers.HBV B.Carrier state:healthy carriers.HBV25 apparent/clinical infectionapparent/clinical infection :The outcomes will be:The outcomes will be:A.Recovery.Shigella A.Recovery.Shigella B.Chronic carrier.B.Chronic carrier.Salmonella typhi Salmonella typhi26 Carrier state:Carrier state:Definition of different types of carriers:Definition of different types of carriers:.incubation carrier .incubation carrier .acute carrier .acute carrier .convalescent carrier .convalescent carrier .chronic carrier .chronic carrier27 Latent infection:Latent infection:After infection,pathogens remain latent inside the body.Develop clinical manifestations when the host immunity has been impaired.Pathogens usually will notbe excreted by the host during period of latency.Herpes simplex28The infection status may change each other in The infection status may change each other in some conditions.some conditions.Latent infection Latent infection Apparent Apparent Carrier status Carrier status Inapparent Inapparent eliminate eliminatefrequencyfrequency/ratioratio 29三、三、Role of Pathogens in Infection Process:Invasiveness:adhesion,penetration ability.Shigella Virulence:toxins,enzymes,and histolytic ability.E.histolytica Infection dose:minimal dose that can cause an infection.S.typhi Variability:change in structure of the pathogen to evade from host immunity.Influenza virus30四、四、The Role of Immune Response in Infection Process:Differentiation between protective immunity and allergy.Protective immunity:beneficial .Allergy(anaphylactic reaction):harmful31 Nonspecific immunity:A.Natural barriers:external(skin,mucous membrane,cilia),internal(blood-brain barrier).B.Phagocytosis:monocytes,macrophages,and granulocytes.C.Humoral factors:complements,lysozyme,interferons(),cytokines32 Specific immunity:Immune respond to specific recognizable antigens.A.Cell-mediated immunity:Important in intracellular infections by viruses,fungi,protozoa and certain bacteria.B.Humoral immunity:Different kinds of antibodies(immune globulins,A D E G M)and their functions.33 Pathogenic Mechanisms of Infectious Diseases 34Establishment and development of infection process can be divided into three stages 1.Portal of entry:Each pathogen has its specific portal of entry.Mycobacterium tuberculosis,Meningococcus -via breath tract.Shigella-via digestive tract.352.localization and Dissemination in the host:Specific for each pathogen.Mumps virus in parotid gland.Hepatitis C virus in the liver.Shigella in the intestine.363.Channels of excretion:Important factor for host infectivity.As the source of infection.Hepatitis A in the stool.Hepatitis B in the blood.Measles virus in expiratory air.37二、二、Mechanism of Tissue Damages 1.Direct invasion:Cytolysis,tissue necrosis,inflammation.2.The actions of toxins and cytokines:Resulting in septic shock,Disseminated intravascular coagulation,DIC etc.3.Immunopathogenesis:Immunosuppression,T-cell destruction,immune complexes induce cytotoxicities.38二、二、Important Patho-physiologic Changes in infection391.Fever(pyrexia):Exogenous and endogenous pyrogens.Exogenous pyrogens:virus etc.Endogenous pyrogens:IL-1,IL-6,TNF,interferon etc.402.Metabolism changes:(1)Protein metabolism:higher proteins catabolism.(2)Carbohydrate metabolism:acceleration of glucolysis.(3)Water and electrolytes metabolism:dehydration,hypokalemia.(4)Endocrine disturbances:higher anabolism,hyper-corticosteroidemia41 Epidemiological Process of InfectiousEpidemiological Process of Infectious42Epidemiological Process(course)include:1.Sources of infection:Human,animal.Patients:acute,chronic;typical,atypical(mild,severe).Subclinical infection:no symptoms.poliomyelitis.Carriers:chronic:typhoid,shigellosis.Infected animals:(natural source)rabies,plague,schistosomiasis.432.Routes of transmission Air,droplets,dusts:e.g.measles,diphtheria.Water,food,flies(fecal-oral infection):e.g.typhoid,cholera.Fingers,utensils(contact infection):e.g.shigellosis,influenza.44 Arthropods:A.Biologic:intermediate hosts,e.g.mosquitoes in malaria,chiggers in scrub typhus.B.Mechanical:passive transfer.e.g.flies in amebiasis45Blood,body liquid transmission Such as HBV,HIVVertical transmission:mother to babyHorizontal transmission:others463.susceptibilitySusceptible person47二、二、Factors Influencing Epidemiological Process481.Natural factors:.Climatic:season,rain,humidity.Geographic:endemicity,schistosomiasis clonorchiasis sinensis:fresh fish2.Social factors:Social system,social-economic condition,cultural background49 Characteristics of Infectious DiseasesCharacteristics of Infectious Diseases501.Basic characteristics:(1)Presence of pathogens.(2)Infectivity:duration of infection,chronic carrier.(3)Epidemiological features:age,sex,season;imported or endemic;sporadic or epidemic and pandemic;epidemic outbreaks.(4)Post-infection immunity.512.Clinical Characteristics:incubation period the period between the invasion of the tissues by pathogens and the appearance of clinical features prodromal period from onset of diseases to apparent clinical features52 Symptomatic period.Apparent of clinical manifestations.convalescent period lighten and disappear clinical manifestations,Lab.normal53relapse re-appear symptom after recovering of diseases.S.typhirecrudescence re-increasing and re-appear,when lighting of clinical symptom and decreasing of temperature.S.typhi.54 sequela body function abnormal after recovering of diseases55Characteristic of infectious disease563.Common symptoms and signs.Fever(pyrexia):A.Effervescence:early stage.B.Fastigium:full-blown stage.C.Defervescence:improvement stage57Fever formsA.Sustained fever:Difference of body temperature less than 1 degree centigrade within 24 hours,over 39.e.g.Second week of typhoid58sustained feversustained fever59B.Remittent fever:Change of body temperature more than 1 degree centigrade within 24 hours,the base line higher than normal.e.g.Septicemia.60remittent feverremittent fever61C.Intermittent fever:Fluctuation between normal temperature and high fever within 24 hours.e.g.Malaria.62intermittent feverintermittent fever63D.Relapsing fever:Fever lasting 57 days with relapse after several days.e.g.Relapsing fever,brucellosis.64relapsing feverrelapsing fever65E.Irregular fever:Curve of body temperature is irregular.e.g.Brucellosis,septicemia66 Skin rash or eruption:67Note appearance type and day of the disease.Eraption time:first day:chickenbox.second day:scarlatina third day:smallbox.forth day:measles.Fifth day:ship fever sixth day:typhoid fever68A.Enanthem:Rash on mucous membrane(mucosa).e.g.Koplik spots in measles.B.Exanthem:Rash on skin surface,e.g.chickenpox,smallpox.C.Maculopapular rash:e.g.Macula and papule (Maculopapule)in measles rose spots in typhoid fever.69maculamacula70papule71herpes and herpes and pustule72d.Urticaria:Seen in:serum sickness,tetenus antitoxin(TAT)parasitic diseases,schistosomiasisdrug hypersensitivity,piperacillin,etc.73(3)Toxemic symptoms:A.General presentations:malaise;headache;anorexiapain in muscles,joints and bonesdisturbance in consciousnessMeningeal irritationseptic shockLiver and kidney failure,etc.74B.Mononuclear-phagocyte system(Reticulo-endothelial system)reactions:hepatomegaly,splenomegaly,lymphadenopathy.754.Clinical forms:(1)development:Acute,subacute and chronic forms.(2)forms of clinical manifestation:mild,moderate(typical)or severe forms.ambulatory form in typhoid (without symptom and signs).76AcuteFever;anoxia,acute-phase protein response,albuminaemia,low serum iron,anemia,neutrophiliaInflammation:pain,dysfunction,tissue damageConvulsion;especially in childrenShock Hemorrhage:hemolytic anemia,intravascular coagulationOrgan failure:kidneys,liver,lung,heart,brain,necrosis of skin77ChronicWeight loss and muscle-wastingMalnutrition:especially associated with diarrheaRetardation of growth and intellect in childrenAnemia:iron sequestrationTissue destruction:e.g.lung in pneumonia or tuberculosis,liver in hepatitis BPost-infective syndromes:e.g:post-viral fatigue syndrome78 Diagnosis of Infectious Diseases791.Clinical manifestations(1)Mode of onset(2)Type of fever(3)Accompanying symptoms:headache,myalgia,arthalgia etc.(4)Signs:Consciousness,jaundice,skin rash,Koplik spot,eschar,subcutaneous hemorrhage,liver,spleen,lymph nodes.80Pathoghomonic signsPathoghomonic signsMeasles:Koplik spotsMumps:swelling of parotid glandScrub typhus:escharLeptospirosis:myalgia,calf muscleTyphoid:rose spotsCysticercosis:subcutaneous nodulesHepatoencephalopathy:flapping tremorShigellosis:mucus-pus-bloody stoolAmebic dysentery:strawberry jam-like stoolRabies:hydrophobia812.Epidemiological Data:(1)History of contact with similar cases.(2)Occupation,living environment and life style.(3)History of vaccination.(4)History of transfusion of blood or blood products.82三、三、Laboratory Examinations:(1)Routine examinations:blood,urine,stool.Leukocytosis,leukopenia,eosinopenia,eosinophilia.liver functions kidney functions,etc.83Leukocytosis:Leukocytosis:Infection with virus:epidemic hemorrhagic fever Japanese B encephalitis infectious mononucleosis rabies Infection with bacteria,etc.84(2)Detection and isolation of pathogens:A.Direct examination:malaria in blood slides,cholerae in stool,diphtheria in throat swab,Entamoeba in rectal scrape,schistosome ova in rectal snip,rickettsia in rash aspirate,fungi in skin scrapings,pneumococci in purulent sputum,leprosy bacilli in slit skin smearBy electron microscopy:viruses in stool;herpes viruses from skinBy histology of biopsy specimen;acid fast bacilli in leprosy and tuberculosis,hepatitis B in liver,rabies virus in brain85B.Culture From blood:typhoid,brucellosis,Gram-negative speticaemia,pneumococcal pneumonia,HIVFrom bone marrow:tuberculosis,brucellosis,histoplasmosisFrom other body fluids,feces or tissues:urinary tract infection,bacillary dysentery,spu