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THE FOLLOWING IS FROM NEW YORK TIMES BESTSELLER BOOK, THE COMING PLAGUE, NEWLY EMERGING DISEASES IN A WORLD OUT OF BALANCE, BY LAURIE GARRETT, PULITZER PRIZE WINNING REPORTER AND AUTHOR OF BETRAYAL OF TRUST, COPYRIGHT 1994 . . . .AMID THE NEAR-FANATIC ENTHUSIASM FOR ANTIBIOTICS THERE WERE REPORTS, FROM THE FIRST DAYS OF THEIR CLINICAL USE, OF THE EXISTENCE OF BACTERIA THAT WERE RESISTANT TO THE CHEMICALS. DOCTORS SOON SAW PATIENTS WHO COULDN'T BE HEALED, AND LABORATORY SCIENTISTS WERE ABLE TO FILL PETRI DISHES TO THE BRIM WITH VAST COLONIES OF STAPHYLOCOCCUS OR STREPTOCOCCUS THAT THRIVED IN SOLUTIONS RICH IN PENICILLIN, TETRACYCLINE, OR ANY OTHER ANTIBIOTIC THEY CHOSE TO STUDY. IN 1952 A YOUNG UNIVERSITY OF WISCONSIN MICROBIOLOGIST NAMED JOSHUA LEDERBERG AND HIS WIFE, ESTER, PROVED THAT THESE BACTERIA'S ABILITY TO OUTWIT ANTIBIOTICS WAS DUE TO SPECIAL CHARACTERISTICS FOUND IN THEIR DNA. SOME BACTERIA, THEY CONCLUDED, WERE GENETICALLY RESISTANT TO PENICILLIN OR OTHER DRUGS, AND HAD POSSESSED THAT TRAIT FOR EONS; CERTAINLY BEFORE HOMOSAPIENS DISCOVERED ANTIBIOTICS. (14) IN YEARS TO COME, THE LEDERBERGS' HYPOTHESIS THAT RESISTANCE TO ANTIBIOTICS WAS INHERENT IN SOME BACTERIAL SPECIES WOULD PROVE TO BE TRUE. THE LEDERBERGS HAD STUMBLED INTO THE WORLD OF BACTERIAL EVOLUTION. IF MILLIONS OF BACTERIA MUST COMPETE AMONG ONE ANOTHER IN ENDLESS TURF BATTLES, JOCKEYING FOR POSITION INSIDE THE HUMAN GUT OR ON THE WARM, MOIST SKIN OF AN ARMPIT, IT MADE SENSE THAT THEY WOULD HAVE EVOLVED CHEMICAL WEAPONS WITH WHICH TO WIPE OUT COMPETITORS. FURTHERMORE, YEAST - THE MOLDS AND SOIL ORGANISMS THAT WERE THE NATURAL SOURCES OF THE WORLD'S THEN BURGEONING ANTIBIOTIC PHARMACEUTICS - HAD EVOLVED THE ABILITY TO MANUFACTURE THE SAME CHEMICALS FOR SIMILAR ECOLOGICAL REASONS. IT STOOD TO REASON THAT POPULATIONS OF ORGANISMS COULD SURVIVE ONLY IF SOME INDIVIDUAL MEMBERS OF THE COLONY POSSESSED GENETICALLY CODED R (RESISTANCE) FACTORS, CONFERRING THE ABILITY TO WITHSTAND SUCH CHEMICAL ASSAULTS. THE LEDERBERGS DISCOVERED TESTS THAT COULD IDENTIFY STREPTOMYCIN-RESISTANT ESCHERICHIA COLI INTESTINAL BACTERIA BEFORE THE ORGANISMS WERE EXPOSED TO ANTIBIOTICS. THEY ALSO SHOWED THAT THE USE OF ANTIBIOTICS IN COLONIES OF BACTERIA IN WHICH EVEN LESS THAN 1 PERCENT OF THE ORGANISMS WERE GENETICALLY RESISTANT COULD HAVE TRAGIC RESULTS. THE ANTIBIOTICS WOULD KILL OFF 99 PERCENT OF THE BACTERIA THAT WERE SUSCEPTIBLE, LEAVING A VAST NUTRIENT-FILLED PETRI DISH FREE OF COMPETITORS FOR THE SURVIVING RESISTANT BACTERIA. LIKE WEEDS THAT SUDDENLY INVADED AN UNTENDED OPEN FIELD, THE RESISTANT BACTERIA RAPIDLY MULTIPLIED AND SPREAD OUT, FILLING THE PETRI DISH WITHIN A MATTER OF DAYS WITH A UNIFORMLY ANTIBIOTIC-RESISTANT POPULATION OF BACTERIA. CLINICALLY THIS MEANT THAT THE WISE PHYSICIAN SHOULD HIT AN INFECTED PATIENT HARD, WITH VERY HIGH DOSES OF ANTIBIOTICS THAT WOULD ALMOST IMMEDIATELY KILL THE ENTIRE SUSCEPTIBLE POPULATION, LEAVING THE IMMUNE SYSTEM WITH THE RELATIVELY MINOR TASK OF WIPING OUT THE REMAINING RESISTANT BACTERIA. FOR PARTICULARLY DANGEROUS INFECTIONS, IT SEEMED ADVISABLE TO INITIALLY USE TWO OR THREE DIFFERENT TYPES OF ANTIBIOTICS, ON THE THEORY THAT EVEN IF SOME BACTERIA HAD R FACTORS FOR ONE TYPE OF ANTIBIOTIC, IT WAS UNLIKELY A BACTERIUM WOULD HAVE R FACTORS FOR SEVERAL WIDELY DIVERGENT ANTIBIOTICS. NOTE: THE PARAGRAPH ABOVE BASICALLY FINISHES THE DISCUSSION OF BACTERIAL RESISTANCE. HOWEVER, I OPTED FOR CONTINUING THIS EXCERPT FROM LAURIE GARRETT'S BOOK BECAUSE I BELIEVE THAT IT MAY BE IMPORTANT SINCE TICKS CAN CARRY VARIOUS MICROBES AND IT IS GENERALLY KNOWN THAT LYME/BABESIA CAN BE A PARTICULARLY DIFFICULT COMBINATION TO CONQUER. TO CONTINUE, THEN: IF MANY YOUNG SCIENTISTS OF THE MID-1960S CONSIDERED BACTERIOLOGY PASSÉ - A FIELD COMMONLY REFERRED TO AS "A SCIENCE IN WHICH ALL THE BIG QUESTIONS HAVE BEEN ANSWERED" - THE STUDY OF PARASITOLOGY WAS THOUGHT TO BE POSITIVELY PREHISTORIC. PARASITE, PROPERLY DEFINED, IS "ONE WHO EATS BESIDE OR AT THE TABLE OF ANOTHER, A TOADY; IN BIOLOGY, A PLANT OR ANIMAL THAT LIVES ON OR IN ANOTHER ORGANISM, FROM WHICH IT DERIVES SUSTENANCE OR PROTECTION WITHOUT MAKING COMPENSATION." (15) STRICTLY SPEAKING, THEN, ALL INFECTIOUS MICROBES COULD BE LABELED PARASITES, FROM VIRUSES TO RINGWORMS. BUT HISTORICALLY, THE SCIENCES OF VIRLOLOGY, BACTERIOLOGY, AND PARASITOLOGY HAVE EVOLVED QUITE SEPARATELY, WHICH FEW SCIENTISTS - OTHER THAN "DISEASE COWBOYS" LIKE JOHNSON AND MACKENZIE - TRAINED OR EVEN INTERESTED IN BRIDGING THE DISCIPLINES. BY THE TIME HEMORRHAGIC FEVER BROKE OUT IN BOLIVIA, THE VERY ARTIFICIAL SET OF DISTINCTIONS HAD DEVELOPED BETWEEN THE FIELDS. PLAINLY PUT, LARGER MICROBES WERE CONSIDERED PARASITES: PROTOZOA, AMOEBAE, WORMS. THESE WERE THE DOMAIN OF PARASITOLOGISTS. THEIR SCIENTIFIC REALM HAD BEEN ABSORBED BY ANOTHER, EQUALLY ARTIFICIALLY DESIGNATED FIELD DUBBED TROPICAL MEDICINE, WHICH OFTEN HAD NOTHING TO DO WITH EITHER GEOGRAPHICALLY TROPICAL AREAS OR MEDICINE. BOTH DISTINCTIONS - PARASITOLOGY AND TROPICAL MEDICINE - SET OFF THE STUDY OF DISEASES THAT LARGELY PLAGUED THE POORER, LESS DEVELOPED COUNTRIES OF THE WORLD FROM THOSE THAT CONTINUED TO TROUBLE THE INDUSTRIALIZED WORLD. THE FIELD OF TROPICAL MEDICINE DID SO MOST BLATANTLY, ENCOMPASSING NOT ONLY CLASSICALLY DEFINED PARASITIC DISEASES BUT ALSO VIRUSES (E. G., YELLOW FEVER AND THE VARIOUS HEMORRHAGIC FEVER VIRUSES) AND BACTERIA (E.G., PLAGUE, YAWS, AND TYPHUS) THAT WERE BY THE MID-TWENTIETH CENTURY EXTREMELY RARE IN DEVELOPED COUNTRIES. IN THE EIGHTEENTH CENTURY THE ONLY ORGANISMS BIG ENOUGH TO BE STUDIED EASILY WITHOUT THE AID OF POWERFUL MICROSCOPES WERE THE LARGER PARASITES THAT INFECTED HUMAN BEINGS IN SOME STAGE OF THE OVERALL LIFE OF THE CREATURE. DOCTORS COULD, WITHOUT MAGNIFICATION, SEE RINGWORMS OR THE EGGS OF SOME PARASITES IN PATIENTS' STOOLS. WITHOUT MUCH MAGNIFICATION (ON THE ORDER OF HUNDREDS-FOLD VERSUS THE THOUSANDS-FOLD NECESSARY TO STUDY BACTERIA) SCIENTISTS COULD SEE THE DANGEROUS FUNGAL COLONIES OF CANDIDA ALBACANS GROWING IN A WOMAN'S VAGINA, SCABIES ASCARIASIS ROUNDWORMS IN AN UNFORTUNATE VICTIM'S SKIN, OR CYSTISERCOSIS TAPEWORMS IN THE STOOLS OF INDIVIDUALS FED UNDERCOOKED PORK. AS BRITISH AND FRENCH IMPERIAL DESIGNS INCREASINGLY IN THE LATE EIGHTEENTH CENTURY TURNED TO COLONIZATION OF AREAS SUCH AS THE INDIAN SUBCONTINENT, AFRICA, AND SOUTHEAST ASIA, TROPICAL MEDICINE BECAME A DISTINCT AND POWERFUL SCIENCE THAT SEPARATED ITSELF FROM WHAT WAS CONSIDERED A MORE PRIMITIVE FIELD, BACTERIOLOGY. SCIENTIST HISTORIAN JOHN FARLEY CONCLUDED THAT WHAT BEGAN AS A SEPARATION DESIGNED TO LEND PARASITOLOGY GREATER RESOURCES AND ESTEEM - AND DID SO IN THE EARLY NINETEENTH CENTURY - ENDED UP LEAVING IT SCIENCE'S STEPCHILD. (16) IRONICALLY, PARASITES, CLASSICALLY DEFINED, WERE FAR MORE COMPLEX THAN BACTERIA AND THEIR STUDY REQUIRED A BROADER RANGE OF EXPERTISE THAN WAS EXACTED BY TYPICAL E. COLI BIOLOGY. TOP PARASITOLOGISTS - OR TROPICAL MEDICINE SPECIALISTS, IF YOU WILL - WERE EXPECTED IN THE MID-1960S TO HAVE VAST KNOWLEDGE OF TROPICAL INSECTS, THE DISEASE-CARRYING ANIMALS, THE COMPLICATED LIFE CYCLES OF OVER A HUNDRED DIFFERENT RECOGNIZED PARASITES, HUMAN CLINICAL RESPONSES TO THE DISEASES, AND THE WAYS IN WHICH ALL THESE FACTORS INTERACTED IN PARTICULAR SETTINGS TO PRODUCE EPIDEMICS OR LONG PERIODS OF ENDEMIC, OR PERMANENT, DISEASE. CONSIDER THE EXAMPLE OF ONE OF THE WORLD'S MOST UBIQUITOUS AND COMPLICATED DISEASES: MALARIA. TO TRULY UNDERSTAND AND CONTROL THE DISEASE, SCIENTISTS IN THE MID-TWENTIETH CENTURY WERE SUPPOSED TO HAVE DETAILED KNOWLEDGE OF THE COMPLEX LIFE CYCLE OF THE MALARIAL PARASITE, THE INSECT THAT CARRIED IT, THE ECOLOGY OF THAT INSECT'S HIGHLY DIVERSE ENVIRONMENT, OTHER ANIMALS THAT COULD BE INFECTED WITH THE PARASITE, AND HOW ALL THESE FACTORS WERE AFFECTED BY SUCH THINGS AS HEAVY RAINFALL, HUMAN MIGRATIONS, CHANGES IN MONKEY* POPULATIONS, AND THE LIKE. IT WAS KNOWN THAT SEVERAL DIFFERENT STRAINS OF ANOPHELES MOSQUITOES COULD CARRY THE TINY PARASITES. THE FEMALE ANOPHELES WOULD SUCK PARASITES OUT OF THE BLOOD OF INFECTED HUMANS OR ANIMALS WHEN SHE INJECTED HER SYRINGE-LIKE PROBOSCIS INTO THE SURFACE CAPILLARY TO FEED. THE MICROSCOPIC MALE AND FEMALE SEXUAL STAGES OF THE PARASITES, CALLED GAMETOCYTES, WOULD MAKE THEIR WAY UP THE PROBOSCIS AND INTO THE FEMALE MOSQUITO'S GUT, WHERE THEY WOULD UNITE SEXUALLY AND MAKE A TINY SAC IN THE LINING OF THE INSECT'S STOMACH. OVER A PERIOD OF ONE TO THREE WEEKS THE SAC WOULD GROW, AS INSIDE THOUSANDS OF SPOROZOITE-STAGE PARASITES ARE MANUFACTURED. EVENTUALLY, THE SAC WOULD EXPLODE, FLOODING THE INSECT'S GUT WITH MICROSCOPIC ONE-CELLED PARASITES THAT CAUSED TO THE COLD-BLOODED INSECT; THEIR TARGET WAS A WARM-BLOODED CREATURE, ONE FULL OF RED BLOOD CELLS. SOME OF THE SPOROZOITES WOULD MAKE THEIR WAY INTO THE INSECT'S SALIVARY GLANDS, FROM WHICH THEY WOULD BE DRAWN UP INTO THE "SYRINGE" WHEN THE MOSQUITO WENT ON HER NIGHTLY SUNDOWN FEEDING FRENZY, AND BE INJECTED INTO THE BLOODSTREAM OF AN UNFORTUNATE HUMAN HOST. AT THAT POINT THE SPEED AND SEVERITY OF EVENTS (FROM THE HUMAN HOST'S PERSPECTIVE) WOULD DEPEND ON WHICH OF THE FOUR KEY MALARIAL SPECIES HAD BEEN INJECTED BY THE MOSQUITO. A GOOD PARASITOLOGIST IN THE 1950S KNEW A GREAT DEAL ABOUT THE DIFFERENCES BETWEEN THE FOUR SPECIES, TWO OF WHICH WERE PARTICULARLY DANGEROUS: PLASMODIUM VIVAX AND P. FALCIPARUM. IF A HUMAN HOST WAS MOST UNLUCKY, THE PARASITES COURSING THROUGH HER BLOODSTREAM WOULD BE P. FALCIPARUM AND SHE WOULD HAVE ONLY TWELVE DAYS TO REALIZE SHE'D BEEN INFECTED AND GET TREATMENT OF SOME KIND BEFORE THE DISEASE WOULD STRIKE, IN THE FORM OF EITHER ACUTE ANEMIA OR SEARING INFECTION OF THE BRAIN. IN EITHER CASE, FOR AN INDIVIDUAL WHOSE IMMUNE SYSTEM HAD NEVER BEFORE SEEN P. FALCIPARUM, THE OUTCOME WOULD LIKELY BE DEATH. . . . . . . . . . ALMOST ENTIRELY ABSENT IN THE MID-TWENTIETH CENTURY WAS AN INTELLECTUAL PERSPECTIVE THAT WEDDED THE ECOLOGICAL OUTLOOK OF THE CLASSICAL PARASITOLOGIST WITH THE BURGEONING NEW SCIENCE OF MOLECULAR BIOLOGY THEN DOMINATING THE STUDY OF NONTROPICAL BACTERIA AND VIRUSES. MONEY WAS SHIFTING AWAY FROM RESEARCH ON DISEASES LIKE MALARIA AND SCHISTOSOMIASIS. YOUNG SCIENTISTS WERE ENCOURAGED TO THINK AT THE MOLECULAR LEVEL, CONCENTRATING ON DNA AND THE MANY WAYS IT AFFECTED CELLS. *or deer or white-footed mice |
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