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EPIDEMIOLOGY

EPIDEMIOLOGY. MORBIDITY VS MORTALITY. SUVEILLANCE OF DISEASE OCCURRENCE REPORTING SYSTEM FROM INDIVIDUAL DOCTORS TO COUNTY, STATE AND FEDERAL PUBLIC HEALTH OFFICIALS CENTERS FOR DISEASE CONTROL AND PREVENTION IN ATLANTA GEORGIA. STATISTICS AND EPIDEMIOLOGY. PROBABILITY OF EXPOSURE

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EPIDEMIOLOGY

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  1. EPIDEMIOLOGY

  2. MORBIDITY VS MORTALITY • SUVEILLANCE OF DISEASE OCCURRENCE • REPORTING SYSTEM FROM INDIVIDUAL DOCTORS TO COUNTY, STATE AND FEDERAL PUBLIC HEALTH OFFICIALS • CENTERS FOR DISEASE CONTROL AND PREVENTION • IN ATLANTA GEORGIA

  3. STATISTICS AND EPIDEMIOLOGY • PROBABILITY OF EXPOSURE • PROBABILITY OF TRANSMISSION

  4. HISTORY OF EPIDEMIOLOGY JOHN SNOW AND CHOLERA

  5. TYPES OF STUDIES • DESCRIPTIVE EPIDEMIOLOGY • ANALYTICAL EPIDEMIOLOGYEXPERIMENTAL STUDIES

  6. DESCRIPTIVE EPIDEMIOLOGICAL STUDIES • DESCRIBES PATTERNS OF DISEASE IN POPULATIONS USING AGE, GENDER, GEOGRAPHIC AREA AND TIME OF OCCURENCE

  7. ESCHERICHIA COLI • E. COLI O157:H7 • JANUARY 1993 -WASHINGTON STATE • SEVERE BLOODY DIARRHEA • FOUND IN HAMBURGER MEAT

  8. ANALYTICAL EPIDEMIOLOGICAL STUDIES • USE SCIENTIFIC METHOD • ESTABLISHES CAUSE AND EFFECT RELATIONSHIPS • COHORT STUDY • CASE CONTROL STUDY

  9. COHORT STUDY • MOST DEFINITIVE • STUDY GROUPS WITH AND WITHOUT RISK FACTORS • LEGIONAIRE’S DISEASE

  10. CASE CONTROL STUDY • INDIVIDUALS WITH DISEASE ARE COMPARED WITH THOSE WITHOUT • HANTAVIRUS

  11. EXPERIMENTAL STUDIES • ANIMAL STUDIES • HUMAN STUDIES

  12. TERMS OF EPIDEMIOLOGY • INCIDENCE • NUMBER OF NEW CASES SEEN IN A SPECIFIC TIME PERIOD • PREVELANCE • TOTAL NUMBER OF CASES AT ANY ONE TIME

  13. MORBIDITY RATE • EXPRESSED AS CASES PER 10,000 PER YEAR

  14. MORTALITY RATE • NUMBER OF INDIVIDUALS WHO DIE AS OF A SPECIFIC DISEASE • PUBLISHED IN MORBIDITY AND MORTALITY WEEKLY REPORTS

  15. PATTERNS OF DISEASE OCCURENCE ENDEMIC, EPIDEMIC, PANDEMIC AND SPORADIC DISEASES

  16. ENDEMIC DISEASE • CONSTANTLY PRESENT • PARTICULAR GEOGRAPHIC AREA • INVOLVES RELATIVELY FEW INDIVIDUALS • NOT MAJOR HEALTH PROBLEM • TUBERCULOSIS AND MUMPS IN US • GONORRHEA AND CHANCROID IN WORLD

  17. EPIDEMIC DISEASE • UNUSUAL OCCURENCE OF DISEASE • INVOLVES LARGE SEGMENT OF POPULATION • FOR LIMITED TIME • ENDEMIC DISEASES CAN BECOME EPIDEMIC • INFLUENZA, MEASLES AND CHICKEN POX

  18. PANDEMIC DISEASE • SERIES OF EPIDEMICS • AFFECT SEVERAL COUNTRIES • MAJOR PORTIONS OF THE WORLD • INFLUENZA PANDEMIC OF 1918-1919 • HIV AND AIDS • GENITAL HERPES AND GENITAL WARTS

  19. SPORADIC DISEASES • UNCOMMON • OCCUR IRREGULARLY • AFFECT FEW PEOPLE • DIPHTHERIA AND WHOOPING COUGH • CAN OCCASIONALLY BECOME EPIDEMIC

  20. TYPES OF EPIDEMICS • COMMON SOURCE • PERSON TO PERSON • http://uhavax.hartford.edu/bugl/histepi.htm • http://en.allexperts.com/e/e/ep/epidemic.htm

  21. COMMON SOURCE EPIDEMICS • SINGLE EXPOSURE SOURCE • RAPID ONSET OF DISEASE CASES • RAPID DECLINE OF DISEASE CASES

  22. PERSON TO PERSON EPIDEMIC • PROPOGATED • SLOW PROLONGED RISE OF CASES • SLOW PROLONGED DECLINE IN CASES

  23. INFLUENZA EPIDEMICS • PRIME EXAMPLE OF PERSON TO PERSON EPIDEMICS • WORLD HEALTH ORGANIZATION TRIES TO LIMIT BY VACCINES • SOMETIMES WORKS SOMETIMES NOT

  24. DISEASE TRANSMISSION

  25. RESERVOIRS • SUPPORTS SURVIVAL, MULTIPLICATION, AND TRANSMISSION • LIVING RESERVOIRS • NONLIVING RESERVOIRS

  26. TERMS • VECTORS • VEHICLES • FOMITES

  27. HUMAN RESERVOIRS • MOST HUMAN PATHOGENS CANNOT LIVE OUTSIDE HOST LONG • MANY RESTICTED ALMOST ENTIRELY TO HUMANS

  28. POTENTIALSOURCES • BODY FLUIDS • FECES • URINE • SEMEN AND DISCHARGES FROM GENITOURINARY TRACT • SALIVA FROM MOUTH • MUCUS FROM RESPIRATORY TRACT • BLOOD • DISCHARGES FROM SORES AND WOUNDS

  29. CARRIERS • HOST WHO HARBORS PATHOGENS THAT ARE TRANSMISSIBLE TO OTHERS • HEALTHY CARRIERS • INCUBATORY CARRIERS • CONVALESCENT CARRIERS • INTERMITTENT CARRIERS

  30. RABIES YELLOW FEVER PLAGUE ROCKY MOUNTAIN SPOTTED FEVER TYPHUS FEVER LYME DISEASE LEISHMANIASIS AFRICAN SLEEPING SICKNESS CHAGA’S DISEASE VIRAL ENCEPHALITIS MALARIA ZOONOSES & VECTOR TRANSMITTED DISEASES

  31. FOMITES VEHICLES NONLIVING RESERVOIRS

  32. PORTALS OF ENTRY • SKIN • MUCOUS MEMBRANES • RESPIRATORY • GASTROINTESTINAL TRACT • URINARY TRACT • PARAENTERAL ROUTE • WOUNDS, ANIMAL BITES, INJURIES • PATHOGENS ARE GENERALLY RESTRICTED TO SPECIFIC PORTALS

  33. INFECTIOUS DOSE • NUMBER OF PATHOGENS NEEDED TO CAUSE DISEASE • VARIES FROM ONE TO HUNDREDS OF THOUSANDS • HIV REQUIRES LARGE DOSES • ENCAPSULATED STREPTOCOCCUS PNEUMONIAE JUST A FEW • PATHOGEN MUST OVERCOME HOST DEFENSES

  34. FACTORS THAT AFFECT INFECTIOUS DOSE • HOST DEFENSES • ABILITY OF MICROBE TO OVERCOME DEFENSES • MALNUTRITION • IMMUNITY OF HOST

  35. PORTALS OF EXIT • DISCHARGED WITH BODY FLUIDS AND WASTES • SNEEZING, COUGHING , TALKING • VAGINA AND SEMEN SECRETIONS

  36. TRANSMISSION • AIRBORNE TRANSMISSION • VEHICLE TRANSMISSION FOOD WATER • DIRECT SEXUAL CONTACT • VECTOR TRANSMISSION ZOONOSES • DIRECT SKIN CONTACT • NOSOCOMIAL TRANSMISSION • TRANSMISSION BY BODY FLUIDS

  37. AIRBORNE TRANSMISSION • COMMON CORYZA • INFLUENZA • LEGIONNAIRE’S DISEASE • TUBERCULOSIS • HISTOPLASMOSIS • COCCIDIOMYCOSIS

  38. VEHICLE TRANSMISSION- • FOOD POISONING OR INTOXICATION • INFECTIONS

  39. FOOD POISONING OR INTOXICATAION • STAPHYLOCOCCAL FOOD POISONING • BOTULISM

  40. VIRAL GASTROENTERITIS BACTERIAL GASTROENTERITIS BACTERIAL ENTEROCOLITIS E. COLI O157:H7 TYPHOID FEVER SHIGELLOSIS HEPATITIS GIARDIASIS CYRPTOSPORIDISOSIS TOXOPLASMOSIS YERSINIOSIS GASTROENTERITIS AND ENTEROCOLITIS

  41. SEXUALLY TRANSMITTED DISEASES • AIDS • GENITAL HERPES • GENITAL WARTS • GONORRHEA • SYPHILIS • NONGONOCOCCAL URETHRITIS

  42. DIRECT TRANSMISSION BY SKIN CONTACT • WARTS • LEPROSY • TINEA

  43. INDIRECT CONTACT • FOMITES ARE CONTAMINATED WITH PATHOGENS

  44. VECTORS • ARTHROPODS ARE MOST COMMON VECTOR • MECHANICAL TRANSMISSION • BIOLOGICAL TRANSMISSION

  45. MECHANICAL TRANSMISSION • SIMPLE PASSIVE TRANSPORT • PATHOGENS ARE CARRIED ON INSECTS (USUALLY) FEET OR BODY PARTS • FLIES ON FOOD

  46. BIOLOGICAL TRANSMISSION • MORE COMPLEX • PATHOGENS REPRODUCE BOTH IN VECTOR AND HOST

  47. ALTERNATE HOST • HOST WHERE ASEXUAL REPRODUCTION OCCURS

  48. DETERMINANT HOST • HOST WHERE SEXUAL REPRODUCTION OCCURS

  49. NOSOCOMIAL INFECTIONS • SERUM HEPATITIS • PUERPERAL FEVER\INFECTIONS AFTER SURGERY

  50. SERUM HEPATITIS • EBOLA

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