TEN GERMS THAT SHOOK THE WORLD RICHARD S. NEIMAN, M.D.

Transcription

1 TEN GERMS THAT SHOOK THE WORLD RICHARD S. NEIMAN, M.D.

2 THE GERM A MIGHTY CREATURE IS THE GERM, THO SMALLER THAN A PACHYDERM ITS CUSTOMARY PLACE IS DEEP WITHIN THE HUMAN RACE ITS CHILDISH PRIDE IT OFTEN PLEASES BY GIVING PEOPLE STRANGE DISEASES DO YOU, MY POPPET, FEEL INFIRM? YOU PROBABLY CONTAIN A GERM! OGDEN NASH

3 GERM SYNONYMS: MICROBE MICROORGANISM MICROSCOPIC ORGANISM INCLUDES BACTERIA, VIRUSES AND PROTOZOA

4 CAUSATIVE AGENTS IN THIS COURSE VIRUSES: AIDS, POLIO, INFLUENZA, SMALLPOX BACTERIA: LEPROSY, TB, CHOLERA, PLAGUE, SYPHILIS PROTOZOA: MALARIA

5 DISEASES IN THIS COURSE NO LONGER A MAJOR THREAT TO MAN SMALLPOX LEPROSY POLIO PLAGUE STILL A MAJOR CAUSE OF ILLNESS AND DEATH TUBERCULOSIS MALARIA INFLUENZA CHOLERA SYPHILIS AIDS

6 VIRUS A MICROSCOPIC INFECTIVE AGENT, TOO SMALL TO BE SEEN BY A CONVENTIONAL MICROSCOPE, CONSISTING OF A NUCLEIC ACID MOLECULE (EITHER DNA OR RNA) IN A PROTEIN COAT. IT IS ABLE TO MULTIPLY ONLY WITHIN THE LIVING CELLS OF A HOST

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9 BACTERIUM A ONE-CELLED ORGANISM THAT HAS A CELL WALL AND AN ORGANIZED NUCLEUS. MOST BACTERIA ARE HARMLESS TO MAN, OTHERS CAN CAUSE DISEASE IN OTHER ANIMALS ONLY, AND STILL OTHERS CAUSE DISEASE IN MAN.

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12 PROTOZAN A ONE-CELLED MICROSCOPIC ORGANISM THAT IS CAPABLE OF MOVEMENT AND BEING A PREDATOR PROTOZOA HAVE MORE COMPLEX LIFE CYCLES THAN BACTERIA

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14 HISTORICAL THEORIES OF DISEASE GOD S PUNISHMENT FOR SIN IMBALANCE OF BODILY HUMORS (BLOOD, BLACK BILE, YELLOW BILE, PHLEGM) UNCLEANLINESS FETID OR POLLUTED AIR COSMIC FORCES ( INFLUENZA DELLE STELLE )

15 THE MICROBE IS SO VERY SMALL YOU CANNOT MAKE HIM OUT AT ALL BUT MANY SANGUINE PEOPLE HOPE TO SEE HIM THROUGH A MICROSCOPE HILLAIRE BELLOC

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20 GERM THEORY MANY DISEASES ARE CAUSED BY MICROORGANISMS THAT INVADE HUMANS, ANIMALS OR OTHER HOSTS. FIRST PROPOSED BY FRACASTORO IN 1546 AND EXPANDED UPON BY VON PLENCIZ IN 1762, BUT WAS NOT ACCEPTED UNTIL PROVEN BY THE WORK OF PASTEUR AND KOCH IN THE 1880s

21 KOCH S POSTULATE TO POSTULATE THAT A GIVEN ORGANISM IS THE CAUSE OF A GIVEN DISEASE, IT IS NECESSARY TO ISOLATE IT FROM A PATIENT (OR EXPERIMENTAL ANIMAL), AND REINTRODUCE IT INTO ANOTHER, THEREBY CAUSING THE SAME DISEASE.

22 ZOONOSIS ANY INFECTIOUS DISEASE OF ANIMALS, USUALLY VERTEBRATES,THAT CAN BE OR HAS BEEN NATURALLY TRANSMITTED TO HUMANS EXAMPLES : AIDS, TB, MALARIA, SMALLPOX, INFLUENZA, LEPROSY

23 RESERVOIR ANY ORGANISM THAT IS CHRONICALLY INFESTED OR INFECTED WITH THE CAUSATIVE AGENT OF A DISEASE AND CAN ACT AS A SOURCE OF FURTHER INFECTION IN OTHERS EXAMPLES: ARMADILLO (LEPROSY), BIRDS AND SWINE (INFLUENZA), RATS (PLAGUE), CATTLE (TB)

24 VECTOR ANY ORGANISM, TYPICALLY A BITING INSECT OR TICK, THAT TRANSMITS A DISEASE OR PARASITE FROM ONE ORGANISM TO ANOTHER. (THE VECTOR MAY OR MAY NOT HAVE THE DISEASE) EXAMPLES: MOSQUITO (MALARIA AND YELLOW FEVER), FLEA (PLAGUE)

25 DEFINITIVE HOST THE HOST (ORGANISM) IN WHICH A PARASITE SPENDS ITS FINAL DEVELOPMENT STAGE AND REACHES FULL MATURITY

26 INTERMEDIATE HOST THE HOST HARBORING A PARASITE THAT GROWS, BUT NOT TO THE POINT OF ULTIMATE MATURITY. IT MAY ACT AS A VECTOR TO REACH ITS DEFINITIVE HOST.

27 ENDEMIC A DISEASE OR CONDITION REGULARLY FOUND AMONG PARTICULAR PEOPLE IN A CERTAIN AREA

28 EPIDEMIC A WIDESPREAD OCCURRENCE OF AN INFECTIOUS DISEASE IN A COMMUNITY AT A PARTICULAR TIME

29 PANDEMIC THE OCCURRENCE OF A PARTICULAR DISEASE OVER A WHOLE COUNTRY OR THE WORLD

30 INDEX CASE THE FIRST DOCUMENTED CASE IN THE ONSET OF AN EPIDEMIOLOGICAL INVESTIGATION OF AN EPIDEMIC, USUALLY, BUT NOT ALWAYS, THE SOURCE OF THE OUTBREAK OF A GIVEN DISEASE

31 IMMUNITY NATURAL IMMUNITY IMMUNITY POSSESSED BY A GROUP OF INDIVIDUALS THAT IS PRESENT IN THEM AT BIRTH ACQUIRED IMMUNITY IMMUNITY ACQUIRED EITHER BY RECOVERING FROM A GIVEN DISEASE (ACTIVE IMMUNITY), OR BY RECEIVING IMMUNIZATION WITH A VACCINE (PASSIVE IMMUNITY)

32 HERD IMMUNITY THE RESISTANCE TO THE SREAD OF A CONTAGIOUS DISEASE WITHIN A POPULATION THAT RESULTS IF A SUFFICIENTLY HIGH PROPORTION OF INDIVIDUALS ARE IMMUNE TO THE DISEASE. THIS MAY OCCUR NATURALLY, BY ENOUGH INDIVIDUALS SURVIVING THE DISEASE AND THEREBY DEVELOPING IMMUNITY, OR, MORE COMMONLY, THROUGH VACCINATION

33 ANTIGEN ANY SUBSTANCE, USUALLY A PROTEIN OR PROTEIN-CONTAINING CHEMICAL, THAT IS CAPABLE OF INDUCING AN IMMUNE RESPONSE IN THE BODY, ESPECIALLY THE PRODUCTION OF ANTIBODIES

34 INCUBATION PERIOD THE PERIOD BETWEEN EXPOSURE TO AN INFECTION AND THE APPEARANCE OF THE FIRST SYMPTOMS. IN MANY CASES, EVEN THOUGH THE PERSON IS ASYMPTOMATIC, HE/SHE MAY STILL BE ABLE TO PASS THE DISEASE TO OTHERS.

35 VACCINE A SUBSTANCE USED TO STIMULATE THE PRODUCTION OF ANTIBODIES TO PROVIDE IMMUNITY AGAINST ONE OR SEVERAL DISEASES, PREPARED FROM THE CAUSATIVE AGENT OR ORGANISM OF THAT DISEASE OR ITS PRODUCTS; OR A SYNTHETIC SUBSTITUTE, TREATED TO ACT AS AN ANTIGEN.

36 ADJUVANT A SUBSTANCE THAT ENHANCES OR INCREASES THE BODY S RESPONSE TO AN ANTIGEN. THE SUBSTANCE IS ADDED TO VACCINES TO INCREASE THEIR EFFECTIVENESS

37 FACTORS AFFECTING INCIDENCE AND SEVERITY OF EPIDEMICS POPULATION AND ITS DENSITY LIVING CONDITIONS WARS EASE OF TRAVEL HEALTH OF EXPOSED POPULATION(S) EFFECTIVENESS OF PREVENTIVE MEASURES MEDICAL PREPAREDNESS MEDICAL ADVANCES

38 FACTORS AFFECTING SEVERITY OF INFECTIOUS ILLNESS GENERAL HEALTH OF INDIVIDUAL NUTRITIONAL STATUS AGE IMMUNOLOGIC STATUS HERD IMMUNITY STRAIN (SUBTYPE) OF OFFENDING ORGANISM (VIRULENCE) SIZE OF INITIAL DOSE OF ORGANISM

39 ANTIBIOTIC VS.ANTIMICROBIAL ANTIBIOTIC A NATURALLY-OCCURRING COMPOUND THAT KILLS OR INHIBITS BACTERIA FROM GROWING ANTIMICROBIAL A COMPOUND, EITHER NATURALLY-OCCURRING OR SYNTHESIZED BY MAN, THAT KILLS OR INHIBITS BACTERIA FROM GROWING

40 DARWINIAN QUANDRY HOW CAN A PATHOGENIC MICROORGANISM SURVIVE IF IT KILLS ITS HOSTS OR RENDERS THEM IMMUNE FROM FUTURE INFECTION? THE ORGANISMS WE WILL DISCUSS HAVE EVOLVED MANY WAYS TO AVOID THIS PROBLEM

41 CHARTACTERISTICS OF THE IDEAL PATHOGEN BE HIGHLY CONTAGEOUS REPLICATE (MULTIPLY) QUICKLY MUTATE FREQUENTLY CONSIST OF MANY IMMUNOLOGICALLY DISTINCT SUBTYPES DO NOT KILL HOST (IF DO, NOT QUICKLY) HAVE A PLACE TO HIDE (RESERVOIR) RESIST THERAPY RESIST VACCINE EFFECTIVENESS

42 WEAPONS USED BY PATHOGENIC ORGANISMS TO SURVIVE MOVE VERY SLOWLY AND DON T KILL YOUR HOST( AT LEAST AT FIRST) SLOW AND STEADY WINS THE RACE SHOW MERCY EXAMPLES: LEPROSY, (AND TO SOME DEGREE TB, SYPHILIS AND AIDS)

43 WEAPONS USED BY PATHOLOGIC ORGANISMS TO SURVIVE KILL SLOWLY, ALLOWING TIME TO SPREAD EXAMPLES: TB SYPHILIS AIDS (MALARIA)

44 WEAPONS USED BY PATHOLOGIC ORGANISMS TO SURVIVE TAKE ADVANTAGE OF PARTICULAR HUMAN BEHAVIOR (SEX!!!!) EXAMPLES: SYPHILIS AIDS

45 WEAPONS USED BY PATHOLOGIC ORGANISMS TO SURVIVE SPREAD EASILY LIKE SOFT BUTTER EXAMPLE: INFLUENZA, CHOLERA

46 WEAPONS USED BY PATHOLOGIC ORGANISMS TO SURVIVE MULTIPLY LIKE CRAZY AND MUTATE WHEN THE HOST DEVELOPS IMMUNITY EXAMPLE: INFLUENZA

47 WEAPONS USED BY PATHOLOGIC ORGANISMS TO SURVIVE HIDE IN WATER, THEN AMBUSH EXAMPLES: CHOLERA POLIO

48 MECHANISMS FOR PATHOLOGIC ORGANISMS TO SURVIVE HIDE YOUR RESERVE FORCES IN ANOTHER ORGANISM TO USE FOR A RAINY DAY EXAMPLES: LEPROSY PLAGUE MALARIA

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50 LEPROSY HANSEN S DISEASE

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52 LEPROSY LEPROSY IS A CHRONIC INFECTION CAUSED BY THE BACTERIUM MYCOBACTERIUM LEPRAE OR M. LEPROMATOSIS. THE DISEASE IS USUALLY ASYMPTOMATIC FOR YEARS, BUT BEGINS WITH PALE OR DARK PATCHES ON THE SKIN THAT HAVE LOST SENSATION BECAUSE OF THE ORGANISM S INVASION AND DESTRUCTION OF NERVES. OVER TIME, THE ORGANISM INVADES OTHER TISSUES OF THE BODY.

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55 LEPROSY BECAUSE OF THE LACK OF SENSATION, PARTS OF EXTREMITIES MAY BE INJURED OR LOST DUE TO REPEATED INJURIES OR INFECTIONS DUE TO UNNOTICED WOUNDS. ALTHOUGH NOT HIGHLY CONTAGIOUS, THE DISEASE IS USUALLY SPREAD BY COUGHING OR CONTACT WITH NASAL SECRETIONS.

56 LEPROSY THERE ARE TWO MAIN TYPES OF THE DISEASE BASED UPON HOW MANY NUMB SKIN AREAS THERE ARE AND BY HOW MANY ORGANISMS ARE PRESENT IN THE AFFECTED AREAS. THEY ARE PAUCIBACILLARY (LEPROMATOUS) OR MULTIBACILLARY (TUBERCULOID). THE DIAGNOSIS IS CONFIRMED BY FINDING THE ORGANISMS IN A BIOPSY OR BY MOLECULAR STUDIES OF AN AFFECTED AREA.

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58 LEPROSY IN THE BIBLE MENTIONED OVER 50 TIMES IN BOTH OLD AND NEW TESTAMENTS THE DESCRIPTIONS IN MOST CASES ARE VAGUE, AND MOST PROBABLY DO NOT REPRESENT A SPECIFIC DISEASE, BUT ANY OF A VARIETY OF SKIN DISEASES ASSOCIATED WITH UNCLEANLINESS, EITHER PERSONAL OR ASSOCIATED WITH SIN BECAUSE IT WAS CONSIDERED PUNISHMENT FOR SIN, THOSE AFFECTED WERE OSTRACIZED

59 LEPROSY THE OLDEST HISTORICAL EVIDENCE OF THE DISEASE DATES FROM ABOUT 2000 BCE, FOUND IN ARCHEOLOGICAL SITES IN PAKISTAN AND INDIA. HIPPOCRATES DESCRIBED THE DISEASE IN ABOUT 460 BCE. IT IS BELIEVED THAT THE DISEASE AROSE IN AFRICA AND SPREAD TO OTHER AREAS ALONG HUMAN MIGRATION ROUTES.

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61 DO FINGERS AND TOES REALLY FALL OFF IN LEPROSY? NO. THE BACILLUS INVADES NERVE ENDINGS AND DESTROYS THE BODY S ABILITY TO FEEL PAIN AND INJURY. WITHOUT FEELING PAIN, PATIENTS CAN INJURE THEMSELVES ON SUCH THINGS AS FIRE, THORNS, ROCKS OR EVEN HOT COFFEE CUPS. INJURIES BECOME INFECTED AND CAUSE TISSUE LOSS, WITH FINGERS AND TOES BECOMING SHORTENED AND DEFORMED.

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63 FATHER DAMIEN A CATHOLIC PRIEST WHO MINISTERED TO LEPERS ON MOLOKAI IN HAWAII FROM AFTER ELEVEN YEARS OF CARING FOR THE PHYSICAL, SPIRITUAL AND EMOTIONAL NEEDS OF THOSE IN THE COLONY, HE CONTRACTED THE DISEASE. DESPITE THIS HE CONTINUED TO WORK. HE WAS BEATIFIED IN 1995

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65 LEPROSY ALTHOUGH INCURABLE FOR CENTURIES, WITH A SLOW INEVITABLE DOWNHILL COURSE, THE DISEASE IS NOW CURABLE USING MULTIDRUG THERAPY PROVIDED FREE OF CHARGE BY THE W.H.O. IN THE 1980s,THERE WERE OVER 5 MILLION CASES WORLDWIDE. IN 2015, THE LAST YEAR IN WHICH FIGURES ARE AVAILABLE, THAT NUMBER WAS ONLY 175,000..

66 LEPROSY ALTHOUGH ONCE GLOBALLY WIDESPREAD, 95% OF CASES AT PRESENT ARE RESTRICTED TO 14 COUNTRIES, WITH HIGHEST CONCENTRATIONS IN INDIA (60%), BRAZIL (15%)AND INDONESIA (8%). OTHER AREAS INCLUDE MOST OF SOUTH ASIA, EASTERN AFRICA AND THE WESTERN PACIFIC.

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68 LEPROSY-CURRENT STATUS LARGELY CONTROLLED IN 2015, THERE WERE ABOUT 175,000 CASES REPORTED WORLDWIDE, WITH 63 IN THE U.S. 95% OF CASES IN INDIA, BRAZIL AND INDONESIA NO VACCINE EFFECTIVE ANTIMICROBIAL TREATMENT AVAILABLE