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1、1,SINGNIFECANCE AND IMPORTANCE,2,History review,In 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。,3,In 1905,Nobel gainer of physiology and medicine award Robert Koch (
2、Germany),Koch discovered tubculosis bacilii,4,In 1945,Nobel gainer of physiology and medicine award Alexander Fleming(Scotland),In 1928年，FlemingDiscorvered PenicillinInto antibiotics era,5,WHO reports：Among 52 million of death in the worldwide annually, 17 million(32%) of death from infectious disea
3、ses 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。,6,Pattern of Infection in Developed Countries,In 20th century, fall in the incidence of communicable diseases i
4、n developed countriesdue to factors such as :Immunizationantimicrobial chemotherapyimproved nutritionand better sanitation and housing.,7,Re-emergence of old infectious disease,(Tuberculosis) (Viral hepatitis) (Sexually transmitted diseases) others: cholera、charcoal,8,Re-emergence of old infectious
5、disease,2 million death of TB in the worldwide annually78 million infected by TB in the worldwide annuallyMarch 24,for World TB Day,9,Emerging infectious diseases,WHO information near 30 years, about 30 kinds of infectious diseases discovered in the worldwide“Emerging infectious diseases”,10,Emergin
6、g infectious diseases,40 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 for World AIDS Day,11,Emerging infectious diseases,SARS （SARSCoV） From 2002.
7、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 century,12,Emerging infectious diseases,Avian influenza H5N1 virus H1N1 VIRUS,13,Antibiotics,Antibiotics, within the last 60 ye
8、ars, 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 ma
9、ke them useless.,14,COMMUNICABLE DISEASES,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 disc
10、iplines. 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. Concept of infectionThe course of struggle between pathogens and human or anim
11、al bodies (host).Absolutely necessary condition,18,Commensalsopportunistic infectionPrimary infectionRepeated infectionMixed infectionSuperinfectionSecondary infection,Kinds of infections,19,Commensalism Pathogens live in the host but dont induce pathologic changes. Escherichia coli in the colon Eps
12、tein-Barr virus,20,Opportunistic infection: Pathogens within the host can induce pathologic changes if host immunity is suppressed by some factors. Cryptococcus neoformans Cytomegalovirus Candida albicans,21,Primary infection: measles, chicken boxRepeated infection: malaria, schistosomiasis, ancylos
13、tomiasisMixed infection: rareSuperinfection: HBV overlap HEVSecondary infection: HBV following bacilli,22,Eliminate pathogeninapparent/sub-clinical infectionapparent/clinical infectionCarrier statusLatent infection,Infections status（infection spectrum） Entrance and colonization of pathogens will lea
14、d to the following results,23, Elimination: pathogens were excluded out by host nonspecific or specific immunity. Such as: Candida albicans Hepatitis A virus,24, inapparent/sub-clinical infection: most frequently occurs in healthy individuals. The outcomes will be: A. Immunity acquired. HAV B. Carri
15、er state: healthy carriers. HBV,25, apparent/clinical infection : The outcomes will be: A. Recovery. Shigella B. Chronic carrier. Salmonella typhi,26, Carrier state: Definition of different types of carriers: . incubation carrier . acute carrier . convalescent carrier . chronic carrier,27, Latent in
16、fection: 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 simplex,28,The infection status may change each other in some conditions. La
17、tent infection Apparent Carrier status Inapparent eliminate,frequency/ratio,29,三、 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.
18、 S. typhi Variability: change in structure of the pathogen to evade from host immunity. Influenza virus,30,四、 The Role of Immune Response in Infection Process: Differentiation between protective immunity and allergy. . Protective immunity: beneficial . Allergy(anaphylactic reaction): harmful,31, Non
19、specific 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 ( ), cytokines,32, Specific immunity: Immune respond to specific recognizab
20、le 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,34,Establishment and de
21、velopment 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.,35,2. localization and Dissemination in the host: Specific for each pathogen
22、. . Mumps virus in parotid gland. . Hepatitis C virus in the liver. . Shigella in the intestine.,36,3. 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、 Mechanism
23、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、
24、 Important Patho-physiologic Changes in infection,39,1. Fever (pyrexia): Exogenous and endogenous pyrogens. Exogenous pyrogens: virus etc. . Endogenous pyrogens: IL-1, IL-6, TNF, interferon etc.,40,2. Metabolism changes:(1) Protein metabolism: higher proteins catabolism.(2) Carbohydrate metabolism:
25、acceleration of glucolysis.(3) Water and electrolytes metabolism: dehydration, hypokalemia. (4) Endocrine disturbances: higher anabolism, hyper-corticosteroidemia,41,Epidemiological Process of Infectious,42,Epidemiological Process(course) include:1.Sources of infection: Human, animal. Patients: acut
26、e, chronic; typical, atypical(mild, severe). Subclinical infection: no symptoms. poliomyelitis. Carriers: chronic: typhoid, shigellosis. Infected animals: (natural source) rabies, plague, schistosomiasis.,43,2. Routes of transmission Air, droplets, dusts: e.g. measles, diphtheria. Water, food, flies
27、(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 amebiasis,45,Blood, body liquid tra
28、nsmission Such as HBV,HIVVertical transmission: mother to babyHorizontal transmission: others,46,3.susceptibility,Susceptible person,47,二、 Factors Influencing Epidemiological Process,48,Natural factors: . Climatic: season, rain, humidity. Geographic: endemicity, schistosomiasis clonorchiasis sinensi
29、s: fresh fish2. Social factors: Social system, social-economic condition, cultural background,49,Characteristics of Infectious Diseases,50,1. Basic characteristics:(1) Presence of pathogens.(2) Infectivity: duration of infection, chronic carrier.(3) Epidemiological features: age, sex, season; import
30、ed or endemic; sporadic or epidemic and pandemic; epidemic outbreaks.(4) Post-infection immunity.,51,2. 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
31、clinical features,52, Symptomatic period. Apparent of clinical manifestations. convalescent period lighten and disappear clinical manifestations,Lab. normal,53,relapse re-appear symptom after recovering of diseases. S. typhirecrudescence re-increasing and re-appear , when lighting of clinical sympto
32、m and decreasing of temperature. S. typhi.,54, sequela body function abnormal after recovering of diseases,55,Characteristic of infectious disease,56,3. Common symptoms and signs. Fever(pyrexia) :A. Effervescence: early stage. B. Fastigium: full-blown stage.C. Defervescence: improvement stage,57,Fev
33、er formsA. Sustained fever: Difference of body temperature less than 1 degree centigrade within 24 hours, over 39. e.g. Second week of typhoid,58,sustained fever,59,B. Remittent fever: Change of body temperature more than 1 degree centigrade within 24 hours, the base line higher than normal. e.g. Se
34、pticemia.,60,remittent fever,61,C. Intermittent fever: Fluctuation between normal temperature and high fever within 24 hours. e.g. Malaria.,62,intermittent fever,63,D. Relapsing fever: Fever lasting 57 days with relapse after several days. e.g. Relapsing fever, brucellosis.,64,relapsing fever,65,E.
35、Irregular fever: Curve of body temperature is irregular. e.g. Brucellosis, septicemia,66, Skin rash or eruption:,67,Note 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: typh
36、oid fever,68,A. 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.,69,macula,70,papule,71,herpes and pustule,72,d.
37、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
38、 shockLiver and kidney failure, etc.,74,B. Mononuclear-phagocyte system(Reticulo-endothelial system)reactions: hepatomegaly, splenomegaly, lymphadenopathy.,75,4. Clinical forms:(1) development: Acute, subacute and chronic forms. (2) forms of clinical manifestation: mild, moderate (typical) or severe
39、 forms . ambulatory form in typhoid (without symptom and signs).,76,AcuteFever; anoxia, acute-phase protein response, albuminaemia, low serum iron, anemia, neutrophiliaInflammation: pain, dysfunction, tissue damageConvulsion; especially in childrenShock Hemorrhage: hemolytic anemia, intravascular co
40、agulationOrgan failure: kidneys, liver, lung, heart, brain, necrosis of skin,77,ChronicWeight loss and muscle-wastingMalnutrition: especially associated with diarrheaRetardation of growth and intellect in childrenAnemia: iron sequestrationTissue destruction: e. g. lung in pneumonia or tuberculosis,
41、liver in hepatitis BPost-infective syndromes: e.g:post-viral fatigue syndrome,78,Diagnosis of Infectious Diseases,79,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
42、, subcutaneous hemorrhage, liver, spleen, lymph nodes.,80,Pathoghomonic signs,Measles: Koplik spotsMumps: swelling of parotid glandScrub typhus: escharLeptospirosis: myalgia, calf muscleTyphoid: rose spotsCysticercosis: subcutaneous nodulesHepatoencephalopathy: flapping tremorShigellosis: mucus-pus-
43、bloody stoolAmebic dysentery: strawberry jam-like stoolRabies: hydrophobia,81,2. 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、 Laboratory Examina
44、tions:(1) Routine examinations: blood, urine, stool. Leukocytosis, leukopenia, eosinopenia, eosinophilia. liver functions kidney functions, etc.,83,Leukocytosis:,Infection with virus: epidemic hemorrhagic fever Japanese B encephalitis infectious mononucleosis rabies Infection with bacteria, etc.,84,
45、(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
46、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 brain,85,B. Culture From blood: typhoid, brucellosis, Gram-negative speticaemia, pneumococcal pneumon
47、ia, HIVFrom bone marrow: tuberculosis, brucellosis, histoplasmosisFrom other body fluids, feces or tissues: urinary tract infection, bacillary dysentery, sputum in pneumonia,86,C. Animal inoculationIntraperitoneal inoculation: Rickettsia tsutsugamushi.Intracerebral inoculation: encephalitis virus.,8
48、7,D. Specific Immunological detection:Detection of microbial antigen (blood, cerebrospinal fluid, sputum, urine)Detection of antibody of IgM class e.g, hepatitis ADemonstration of antibody Rising titre: typhoid, brucellosis, HIV infectionSkin testing: Tuberculosis, histoplasmosis, Nonspecific,88,F.
49、Molecular biologic assay: Using isotope or non-isotope probes; Polymerase chain reaction(PCR). hepatitis C virus, etc.,89, other examinationX ray: lobar pneumonia, renal tuberculosis, muscular cysticercosisIsotope: detection of abscessUltrasound: abscess hydatid cystComputed tomography (CT) or magne
50、tic resonance imaging (MRI): intracranial infection, visceral abscesses,90,Treatment of Infectious Diseases,91,Principles of therapy 1. Aim of treatment: . for alleviation of symptoms and signs . for isolation of patients . Comprehensive treatmentincludes drug therapy, nursing care and isolation. .
