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Title: UNIT 9: DISEASES AND DISORDERS:


1
UNIT 9 DISEASES AND DISORDERS
  • An infection occurs when living agents enter
    tissue, multiply there and damage the tissue.

2
The General causative agents for disease include
  1. bacteria
  2. viruses
  3. fungus
  4. Rickettsia
  5. protozoan
  6. arthropods (acting as vectors)
  7. vermiform (various invertebrate worms)

3
STAPHYLOCCOCCAL INFECTIONS (bacteria)
  • Staphyloccocci are spherical gram positive
    bacteria about .5 to 1.5 miccrometers in
    diameter.
  • They tend to form in irregular clusters like
    grapes
  • Staphylococcus aureus is the most pathogenic of
    the staphylococci (forms golden yellow colonies,
    almost all pathogenic and produces coagulase for
    blood clotting)
  • S. Aureus common problem in hospital s due to
    being carried on the skin of patients, visitors
    and the danger of infection of surgical wounds or
    skin breaks is high .

4
  • S. aureus is difficult to treat and is very
    resistant to many antibiotics..mainly due to
    resistance to penicillinase.
  • S aureous often enters the body via natural
    openings in the skin barrier, hair follicles
    ect, if through mouth (food poisoning)
  • Antibiotics do not penetrate abscesses well, thus
    making the infection more difficult to treat,
    often draining pus from abscess is one of the
    first steps of treatmenttreat with penicillin or
    erythromycin.

5
  • Staph infections on newborns includes impetigo
    (vesicles on the skin rupture and crust over), or
    scalded skin syndrome ( lesions on the nose and
    mouth, then bright red area appears, within 48 hr
    the skin of palms and soles peels off in sheet
    when touchedserious illness)
  • 30 to 50 health adults carry staph in their nose
    and 20 carry staph on their skin.. and the human
    immune system is good at combating staph
    infections ( most susceptible include infants,
    elderly drug users and immune impaired)

6
scalded skin syndrome
7
  • The boils that Job scraped with broken pottery
    (Job 27-8) could only have been caused by staph

8
STREPTOCCOCAL INFECTION including flesh-eating
bacteria
  • Streptococci are gram positive spherical bacteria
    with cells growing in chains.
  • They are facultative anaerobes
  • Many are nonpathogenic and occupy the mouth,
    gastrointestinal tract and upper respiratory
    systems.
  • Some Streptococci are responsible for skin
    infections and secrete several enzymes including
    hemolysins (damages RBCs)
  • Impetigo is one disease caused by Strep
    infections (symptoms include superficial skin
    infection, isolated pustules( round elevations
    full of pus) that become crusted and rupture

9
Impetigo is one disease caused by Strep infections
10
  • Strep also causes scarlet fever, infections of
    the throat
  • Steptococcus pneumonia most common cause of
    bacterial pneumoniaand also the cause of
    flesh-eating bacteria (necrotizing fasciitis )
  • S. pneumonia is highly resistant and emits an
    enzyme able to destroy the fascia, or tissue that
    binds skin to muscle at a rate of an inch an
    hourabout 1500-2000 cases in USA per year with
    fatality rate of 30 in otherwise healthy adults.

11
necrotizing fasciitis
12
  • Jim Henson from muppets died of this bacteria in
    1990 from a splinter cut on his finger (duration
    from time of splinter to death6 weeks)

13
PSEUDOMONADS (bacteria)
  • Aerobic gram negative rods, widespread in soil
    and water, able to survive in any moist
    environment.
  • Cause otitis externa (swimmers ear)
  • Pseudomonas dermatitis causes rash outbreaks and
    is associated with swimming pools

14
  • Pseudomonas aeruginosa common and serious
    opportunistic pathogen in burn patients (esp 2nd
    and 3rd degrees), it is carried on flowers or
    plants sent by well-wishers, thus reason
    hospitals do not permit these patients to receive
    flowers.
  • Treatment with antibiotics gentamicin and
    carbenicillin, (Silver sulfadiazine used in burn
    victims)

15
WARTS viral
  • Caused by Viruses that stimulate an uncontrolled
    but benign growth of skin cells, they can be
    transmitted from one person to another by
    contact.
  • Medical treatment includes applying extremely
    cold liquid nitrogen to them, drying them with
    electric current, or burning them off with acid.
  • Some skin or cervical cancers associated with
    this papillomarivius.

16
SMALL POX (VARIOLA VIRUS)
  • During middle ages 80 of population expected to
    contract small pox
  • Two basic forms of this disease variola major
    (mortality rate 20), and variola minor
    (mortality rate 1)
  • Transmission and progression is via respiratory
    route, the virus infect many internal organs
    before eventually moving into the blood
    (viremia)this leads to infection of the skin and
    the production of more recognizable symptoms (
    virus in epidermal layers causes skin lesions
    that house the virus) .

17
  • Rameses V (1156B.C.) showed evidence of small pox
    rash,
  • Pocahontas (1617) died of small pox

18
  • Last outbreak in the USA was in 1947, routine
    vaccinations for small pox were discontinued in
    the United States in 1971 when it was deemed that
    the vaccination posed a greater threat that did
    contracting
  • Ali Maow Maalin

19
Ali Maow Maalin
The last known case of wild smallpox occurred in
Somalia in 1977
20
HERPES SIMPLEX (VIRUS)
  • Greek meaning to creep
  • both types of herpes simplex viruses may spread
    to the brain and cause herpes encephalitis, type
    2 70 mortality if untreated
  • About 90 of the population of the United States
    has been infected with the herpes simplex
    virusinitial infection usually during infancy,
    and often subclinical.
  • About 15 of the cases develop lesions known as
    cold sores or fever blisters (usually occurring
    in oral or nasal mucous membranes) these lesions
    heal and the infection subsides but recur when
    the infection strengthens again ( due to
    hormonal, emotional stress or drop in immune
    system)

21
  • Between recurrences, herpes simplex type 1
    viruses are latent in the trigeminal nerve
    ganglia communication between the face and the
    central nervous system.
  • Herpes simplex 2 virus is transmitted via sexual
    contact (lesions appear after incubation period
    of 1 week and cause a burning sensation, after
    which vesicles appear) urination can be painful,
    and walking uncomfortable. ( vesicles heal in a
    couple of weeks and contain the virus)( location
    of vesicles in female external genitals, males
    base of penis)

22
  • Herpes simplex 2 has latent periods and active
    periodsvarying per personit can cross placental
    barriers and affect fetusbirth is via c section
    to prevent spread of disease to baby if the
    disease has not spread thru placenta
  • There is no cure for genital herpes, however
    Acyclovir can be administered topically or
    orally.

23
  • Shakespeare wrote of this unsightly curse in
    Romeo and Juliet Oer ladies lips, who
    straight on kisses dream/Which oft the angry Mab
    with blisters plagues,/Because their breaths with
    sweetmeats tainted are

24
MEASLES (RUBEOLA VIRUS)
  • Extremely contagious disease that spread by the
    respiratory route.
  • Person with measles is infectious before symptoms
    appear, thus quarantines not effective
  • Humans are the only reservoir for measles,
    although monkeys are also susceptible.
  • Law requires immunization for schoolvaccines
    being 95 effective.

25
  • Development and progression of rubeola begins in
    the upper respiratory systemincubation period of
    10-12 days, symptoms develop including sore
    throat, headache, and cough, followed by a
    papular rash appearing on the skin, lesions of
    the oral cavity include Koplik spots ( tiny red
    patches with central white specks (helpful for
    diagnostics) on the oral mucosa opposite the
    molars
  • Measles is extremely dangerous disease,
    especially in very young or elderly. (1 in 3000
    cases fatal in infants, complications such as
    encephalitis occur, if at all, about a week after
    the rash appears) and can cause severe birth
    defects if an expecting mother contracts german
    measles

26
Koplike patches indicating measles
27
SCABIES arthropod
  • Infection of the human skin caused by the mite
    Sarcoptes scabiei, a parasitic arthropod.
  • The disease is most common among school children
    and is also found in adultssometimes occurring
    as a nosocomial infection.
  • The fingers, wrist, and elbows are the most
    frequent sites of infection.
  • The mite burrow into the skin and fill the tunnel
    with their eggs and feces.
  • The eggs hatch, and new mites mature, mate and
    lay more eggs, perpetuating the life cycle.

28
  • Symptoms are the result of hypersensitivity
    reactions to the mites, and first occur 2 to 6
    weeks after the initial infection.
  • main symptom is itching especially when the skin
    is warm (ex in bed at night), a red raised
    lesions (erythematous papules) develop, which may
    become infected with bacteria through scratching.
  • Diagnosis is made by examination of the skin with
    a 10X hand lens to id burrows, sometimes the
    mites can be picked out with a needle for
    microscopic examination.
  • Treatment is by a topical application of gamma
    benzene hexachloride (kwell) , with bedding and
    other personal objects sanitized.

29
Scabies
30
CUTANEOUS MYCOSES (fungal) ringworms and
athletes foot
  • Fungi that colonized the hair, nails and outer
    layer of the epidermis are called dermatophytes
    and their infection are called dermatomycoses.
  • Dermatophytes grow on the karatin present in
    those locations, causing ringworms ( most being
    asymptomatic and removed for cosmetic reasons,
    named from Greek time period who believed the
    infection to be caused by worms)

31
  • Dogs and cats are frequently infected with
    ringworms, as well as humans, if ring worms are
    in the groin region it is called jock itch, if on
    the feet it is athletes foot
  • Treatment is of a variety of topical medications
    including miconazole, or clotrimazole, or with
    oral medication such as griseofulvin.

32
  • Ring worms
  • Athletes foot

33
CANDIDIASIS Fungi
  • The infection of the mouth with the fungi Candida
    albicans, which is not affected by antibacterial
    drugs, and will sometimes overgrow the mucosal
    tissue when normal bacterial flora are
    suppressed.
  • Newborns infants, whose normal flora have not yet
    established are often afflicted with candidiasis
    of the oral cavity called thrush
  • Elderly, diabetics, and cancer patients can be
    afflicted with candida in the mucosal tissues of
    the vaginitis.
  • Treatment is usually with a topical application
    of miconazole, clotrimazole, or nystiatin.

34
Thrush
35
CONTATGIOUS CONJUNCTIVITIS pinkeye bacteria
  • Caused by Hemophilus aegytius, and is transmitted
    by hand contact or by flies.
  • Treatment topical application of antibiotics
    (vary)

36
BACTERIAL MENINGITIS
  • An inflammation of the meninges caused by gram
    negative bacteria.
  • Most patients suffering from any type of
    meningitis complain of headache and have symptoms
    of nausea and vomiting, convulsions and coma
    accompany the infection in many cases.
  • Mortality rate varies with pathogen but is
    generally high for an infectious disease
    todaymany survivors suffer from various
    neurological damage.

37
Meningitis caused by different types of pathogens
(viruses, bacteria, fungi, protozoan)
  • There are 3 major types of bacterial meningitis
  • meningococcal meningitis caused by Neisseria
    meningitides mortality rate 27
  • pneumococcal meningitis caused by Streptococcus
    pneumonia mortality rate 11
  • Hemophilus influenza mortality rate 43 most
    common
  • Diagnosis is via analysis of cerebral spinal
    fluid and blood.
  • Treatment is though a strengic regime of various
    antibiotics including Rifampin, penicillin and
    ampicillin

38
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39
TETANUS bacteria
  • Causitive agent is Clostridium tetani, an
    obligate, anaerobic,endospore-forming, gram
    positive rod that is common in soil contaminated
    with animal feces.
  • Symptoms are caused by an extremely potent
    neurotoxin (tetanospasmin) that is released upon
    the dath and lysis of the growing bacteria.(
    potent enough that the amount of toxin in the ink
    of one . could kill 30 people)
  • In normal muscle operations, one muscle contracts
    and the opposing muscle relaxes

40
  • This neurotoxin blocks the relaxation pathway so
    that both the muscles contract, resulting in
    characteristic muscle spasms (if in the jawlock
    jaw)
  • Mode of transmission is improperly cleaned deep
    puncture wounds, especially those with little or
    no bleeding, immunization is 100 effective and
    boosters of every 10 years maintains
    immunity..(DPT diphtheria, pertussis, tetanus)
  • Recovery does not confer immunity, an d about
    560,000 babies die each year in Asia and Africa
    because their umbilical cords are cut with filthy
    instruments or the stump is packed with dirt.

41
Tetanus
42
BOTULISM Bacteria
  • Caused by Clostridium botulinum, an obligately
    anaerobic, endospore-forming, gram-positive rod
    that is found in soil and many freshwater
    sediments.
  • Ingesting the endospore usually does no harm,
    however in anaerobic environments, ex sealed
    cans, the microorganisms produces an exotoxin
    that is highly potent.
  • Persons suffering from botulism undergo
    progressive flaccid paralysis for 1-10 days and
    may die from respiratory and cardiac failure.

43
  • Symptoms include nausea, but no fever, varying
    neurological safe) , difficulty swallowing
    ,general weakness, blurred Recovery does not
    confer immunity
  • First described 1800s with blood sausage (blood
    and ground meat tied in pig stomach and
    incubated)
  • Botulin toxin not formed in foods with acidity
    below ph 4.7 ( ex tomatoes
  • Mortality rate 25 to 40
  • Treatment relies heavily on supportive care,
    antibiotics of no use because toxin is preformed
  • Diagnosis by inoculation of mice with samples
    from patients serum, stool, or vomitus

44
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45
LEPROSY BACTERIA
  • Causitive agent Mycobacterium leprae, an
    acid-fast rod, with an optimum growth temperature
    of 30 C
  • first isolated and identified about 1870.
  • Sometimes called Hansens disease (avoid term
    leprosy)

46
Two main forms
  1. tuberculoid (neural) form characterized by
    regions of skin that have lost sensation and are
    surrounded by a boreer of nodules. Recovery
    sometimes spontaneously
  2. lepromatous (progressive) form skin cells are
    infected and disfiguring nodules form all over
    bodymucous membrane of nose affected,
    deformation of hand into clawed form and necrosis
    of tissue

47
  • Both forms are spread by transfer of bacteria
    from lesions or inanimate objects exposed to
    lesion discharge
  • Patients can be made noncommunicable within 4-5
    days by administration of sulfone drugs
  • National leprosy hospital in Carville Lousiana
    reports about 200 cases a year.
  • No vaccine for leprosy currently exists

48
POLIOMYELITIS Virus
  • Causitive agent poliomyelitis virus
  • Best known as a cause of paralysis, however, only
    about 10 of infected people develop identifiable
    symptoms, and the paralytic form probably
    affects less that 1 of those infected.
  • Symptoms often asymptomatic or mild and may
    include headache, sore throat, fever and nausea.
  • Humans only known natural host
  • Primary mode of transmission is ingestion of
    water that is contaminated with feces containing
    virus

49
  • Occurrence more often in summer months in
    temperate regions
  • Predilection sites tonsils, lymph nodes of neck
    and ileum
  • Diagnosis based on isolation of virus from feces
    and throat secretions
  • Preventives Salk vaccine and Sabin vaccine (more
    common in USA, less expensive and oral medication
    of orange flavored medicine)

50
Polio
51
RABIES virus
  • An acute infectious disease that usually results
    in fatal encephalitis.
  • Causative agent is rabies virus (rhabdovirus)
    with a characteristic bullet shape
  • Mode of transmission bite of an infected animal,
    even the lick of such an animal can transmit the
    virus
  • Bats probably transmit the disease among
    themselves via inhalation of virus in guano (
    documented cases of aerosol transmission to
    human who spelunker)

52
  • Initially the virus multiplies in skeletal
    muscles and connective tissue then enters the
    peripheral nerves to the central nervous system
    where it causes encephalitis
  • Symptoms spasms of muscles of mouth and pharynx
    when liquid is swallowed, later stages just the
    sight of water causes spasms (hydrophobia), final
    stages result from extensive damage to the nerve
    cells of the brain and spinal cord.Death
    inevitable

53
  • 2 forms of the disease
  • furious rabies dogs highly excitable and snap at
    anything within reach
  • Dumb (paralytic) rabies common in cats, only
    minimal excitability
  • Treatment Pasteur treatment (14-21 inoculations)
    and more recent human diploid cell vaccine (HDCV)
    (5-6 inoculations)
  • Carriers skunks 46, bats 19, foxes 10,
    raccoons 10,domestic animals 6, dogs 6.seldom
    in rabbits, squirrels or mice

54
Rabies
55
AFRICAN TRYPANOSOMIASIS protozoan
  • Causes African sleeping sickness..
  • Causative agent Trypanosoma brucei gambiense, a
    flagellate that is injected by the bite of the
    tsetse fly (arthropod vector)
  • Predilection site blood
  • Symptoms decreased physical activity and mental
    acuity, if untreated, the host enters a coma and
    death is inevitable.
  • Treatment drugs only affective when central
    nervous system is not affected,, drugs kill 99
    but the remaining 1 becomes immune and multiply
    in the blood, new antibiotics are used and 99
    are killed and the 1 become immune and rebuild
    the numbersmaking this a difficult condition to
    treat.

56
African sleeping sickness
57
NAEGLERIA FOWLERI protozoan (amoeba)
  • A protozoan known to cause neurological disease.
  • Symptoms flu-like and death within one weak
  • Etiology the spore enters a broken mucous
    membrane, usually oral or nasal and the
    protozoan migrates to the brain where it causes
    encephalitis like conditions and death.
  • Most common victims are children who swim in
    ponds or streams.
  • Only a few cases per year are reported, bur
    fatality rate is nearly 100

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59
ANTHRAX Bacteria
  • Common names include splenic fever, mrrian (
    biblical term for anthrax), and charbon to name a
    few
  • Anthrax is an acute infectious febrile disease of
    virtually all animals caused by Bacillus
    anthracis and is generally septicemia in nature
    but may be localized.
  • Clinically characterized in a very short course
    (10-12 hrs)
  • Generally appears in late spring and summer
  • It is an aerobic, encapsulated rod, gram
    positive, not acid fast and oxygen is necessary
    for sporulation. Vegetative form is easy to kill
    with disinfectant, 12oF also kills this bacteria

60
  • Mode of transmission is ingestion, inhalation,
    biting insect,
  • Incubation period 1-14 days usually 3-6Prognosis
    unfavorable
  • Symptoms increased pulse rate (rapid but weak),
    temp 104F, spleen enlarged, edema of lungs, Post
    mortal findings rigor mortis is incomplete or
    completely absent

61
3 types of Anthrax
  1. cutaneous anthrax characterized as pustular
    infection of skin, danger of septicemia
  2. Inhalation anthrax endospores are inhaled, high
    fever, difficulty breathing and chest pain,
    septicemia and high mortality rate
  3. Ingestion anthrax ingest endospores and enters
    gastrointestinal tract

62
KURU AND MAD COW DISEASE
  • Kuru occurs in isolated groups of cannibals who
    eat brains.

63
TAPEWORMS
  • Often asymptomatic
  • Includes Taenia saginata beef tapeworm,
    infestations begin with the consumption of
    undercooked beef, pork, or fish, adult worms can
    live in the intestines for up to 25 years and
    reach lengths of 6 meters (18 feet)
  • Symptoms abdominal discomfort, psychological
    distress, when several feet pass through anus,
    flatulence
  • Drug of choice to eliminate the infection is
    niclosamide

64
NEMATODES
  • Round worm infections including the following
  • pinworms Enterobius vermicularis. Which
    migrates out anus of human host to lay eggs,
    causing local itchingtreat entire house with
    pyrantel pamoate, or mebendazole contraction is
    oral fecal generally children putting dirty
    fingers in mouth.

65
  • hookworms Necator americanus. Attaches to
    intestinal wall and feeds on blood and tissue,
    can lead to anemia, or craving unusual food such
    as soil or laundry starch, contact is bare skin
    in soil, treat with mebendazole.

66
  • Ascariasis Ascaris lumbricoidescan grow up to
    one foot in length, live in intestinal tract and
    often diagnosed when adult worm emerge from
    anus, may be coughed up and swallowed allowing
    for migration to throat, lungs, or abdominal
    cavity.
  • Effectively treated with mebendazole

67
CHINESE RESTRANT DISEASE bacterial
  • Aka Monosodium glutamate (MSG) which can cause
    chest pain, burning sensations, and feeling that
    your face is blowing up like a balloon.
  • The effects depend on how much MSG and vary from
    person to person but is a reminder that MSG is
    manufactured by Corynebacterium glutamicum, a
    cousin to the diphtheria germ

68
TUBERCULOSIS bacteria
  • A chronic bacterial disease caused by
    Mycrobacterium tuberculosis, characterized
    clinically by wasting of the body and
    granulomatous tubuncles.
  • Often called white death, it is referred to in
    the BibleIt was the plague of the pharaohs
  • Mode of transmission picked up by injection,
    inhalation, wound contamination

69
  • Etiology it is a slender, rod shaped obligate
    aerobe, stains gram positive, is acid fast,
    moderate resistance to heat, may stay alive under
    moderate conditions 2-4 years
  • Symptoms gradual lose of weight , coughing,
    apnea, partial loss of appetite, unusual signs or
    symptoms depending on where the lesion is
    located, if body has enough resistance to the
    first tubercle, it may become walled off by scar
    tissue and never do any other damage to the body
    or spread further ( occurred with Marie Currie)
  • Prognosis unfavorable Incubation time not
    definite time

70
  • By law cattle must me branded on the left jaw
    with a T to indicate TB positive animals and a
    reactor tag is placed in left ear ( red tag)
  • Charles Dickens character David Copperfield died
    of tuberculosis. Well known personalities that
    suffered from TB included King Tut, Edgar Allan
    Poe, Chopin, Robert Louis Stevenson, Adolph
    Hitler, Nelson Mandela
  • Treatment today various drugs are used to treat
    TB including streptomycin, isoniazid (INH) and
    rifampin

71
  • Charles Dickens character David Copperfield died
    of tuberculosis.
  • Well known personalities that suffered from TB
    included King Tut, Edgar Allan Poe, Chopin,
    Robert Louis Stevenson, Adolph Hitler, Nelson
    Mandela

72
YELLOW FEVER arthropod borne virus
  • Historically important because it was the first
    such virus discovered and provide the first
    conformation that an insect could transmit a
    virus.
  • The virus is injected into the skin by the
    mosquito ( Aedes aegypti is the vector)
  • Symptoms fever, chills, headache, backache,
    nausea, jaundice
  • Treatment none
  • Incubation period 4-18 days
  • Vaccine good for 6 years

73
DENGI virus
  • Acute but rarely fatal viral disease transmitted
    by the mosquito Aedes aegypti.
  • Sometimes called breakbone fever, characterized
    by acutely high fever ,followed by a rash 2-4
    days later (mainly on trunk, never on palms of
    hands or soles of feet)
  • Generally will occur between Sept and November
  • No specific treatment against the virus

74
HOT VIRUS
  • ONE THAT SPREADS EASILY, KILLS QUICKLY, WITH HIGH
    MORTALITY RATE, AND HAS NOT CURE OR PREVENTIVE
    VACCINE

75
VIRAL HEMORRAGIC FEVERS (MARBURG/EBOLA
76
Marburg (city in Germany)
  • 1967 3 factory workers became nauseated and began
    to vomit.
  • Diarrhea set in eyes became severely bloodshot
    and a painful rash occurred ( due to blood
    clotting in thousands of capillaries), their
    throats became so raw they could not swallow and
    had to be fed intravenously
  • within 10 days they began vomiting and defecating
    bloodblood and Marburg virus gush in all
    directions
  • If the virus lands on another human, the horrid
    cycle of infection begins again, killing about
    25 of the people infected
  • very lethal virus (only 3 documented outbreaks
    1967,1976,1990

77
  • The virus looked like a short piece of yarn (
    thus called filovirus) unlike the spherical shape
    of most viruses.
  • Many scientist believe that this was an emerging
    virus ( one that had jumped into a new animal
    species.
  • reason it was uncommonly deadly and the new host
    has never been exposed to the virus, and the
    hosts immune system has no defense against the
    virus.
  • both Marburg,and Ebola are Biosafety level 4
    agents, kept under constant negative air pressure
    to ensure no escape of the virus as compared to
    HIV with is only a level 2 virus

78
Ebola (river in Zaire)
  • First appearance 1976 (325 of 358 dead),
  • kills 90 of its victims,
  • it can attack and amplify itself in virtually
    any body tissue except bone and perhaps skeletal
    muscle.
  • Characterized by seering headache, fever and
    muscle pain, then the bleeding starts (internal
    hemorrhaging and the bodys clotting factors
    begin, organs such as liver and spleen are
    transformed into hardened masses of coagulated
    blood and tissue, kidneys become so clogged with
    blood that they cease to function, blood flows
    into lungs, stomach and intestines death soon
    follows often from shock , heart failure or lung
    congestion
  • Ebola does in 10 days what it takes AIDs ten
    years to do
  • it is a filovirus( shaped like a question mark),
    transmitted by air, but luckily not easily
    transmitted from human to human through casual
    contacthospitals where greatest miniepidemics
    occur.

79
  • Antibodies have been collected and used to treat
    victims of hot virus diseases.
  • The blood of one nun, a survivor of Ebola, was
    repeatedly tapped for its Ebola antibodieswhen
    injected into a person during the early stages of
    Ebola fever, it sometimes proved beneficial

80
CHAGAS protozoan
  • A protozoan disease of the cardiovascular system
  • Causitive agent is Trypanosoma cruzi , a
    flagellated protozoan
  • Affects 40 to 50 of population in rural areas of
    S. America
  • Reservoir include rodents, opossums, and
    armadillos

81
  • Arthropod vector is the reduviid bug (kissing
    bug)that bites humans or animals around the lips
    the wound is scratched and the trypanosome enters
    the would
  • Most damage is due to inflammation around the
    wound but the nervous system can be affected (
    loss of involuntary muscle contraction in
    esophagus and gastrointestinal tract
  • Treatment is difficult in chronic progressive
    stage Nifurtimix drug of choice for treatmentno
    cure

82
  • Some believe that Charles Darwin contracted
    chagas on his voyage on the H.M.S. beagle
  • He was known to have been bitten by the kissing
    bug

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MALARIA protozoan
  • Characterized by chills, fever and often vomiting
    and severe headache Causitive agent is
    Plasmodium falciparum, carried by the mosquito
    vector Anopheles
  • The sporozoite enters the bloodstream of bitten
    human within 30 minutes of bite, reproducing and
    moving to the bloodstream where it causes RBCs to
    rupture and the release of the mature
    merozoites.fever reaches 104F, sweating begins,
    fever subsides and patient feels normal until
    cycle begins again ( if 1 RBC infected then over
    100,000,000,000 parasites in circula

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  • Treatment is with quinine, or quinine derived
    antibioticsno effective control of malaria in
    sight

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LYME DISEASE spirochete
  • Named after location identified (Lyme
    Connecticut)
  • Number 1 tic-borne disease in USACausitive agent
    is the spirochete Borrelia burgdorferi and the
    vector being a tic Ixodes pacificus

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  • Symptoms usually a rash appearing near bite site
    that expands out to about 15 cm ( bullseye
    appearance) followed by flu like symptoms.if
    untreated the heart can become affected (possible
    requiring a pacemaker) and neurological symptoms
    can occur (face paralysis, meningitis,
    encephalitis) other symptoms include chills,
    headache, and muscle pain
  • Treat with antibiotics but the later diagnosed
    the more difficult the treatment

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Bulls eye rash
Lyme disease
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ROCKY MOUNTAIN SPOTTED FEVER rickettsia
  • The number 2 tic-borne disease in USA
  • This rickettsia is a parasitic Tick borne disease
    that is passed form one generation of ticks to
    another through their eggs (transovarian passage)
  • Causitive agent is Rickettsia rickettsia , major
    tic vectors are Dermacentor andersoni (west) and
    D. variabilis (east)

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  • Symptoms About one week after bite a rash
    appears (often on palms and soles...which does
    not occur with viral rashes) resulting in leakage
    of blood into surrounding tissues, fever and
    headache follow,, death in about 3 cases
  • Treat with Antibiotics such as testracycline and
    chloramphenicol very effective

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TICK PARALYSIS
  • Called ascending flaccid paralysis
  • Possibly due to a toxin in the tic saliva,
    usually affects children
  • Incubation period is 4-7 days, most cases in May
    and June
  • Host wakes up paralyzed removal of tic results
    in full recoverylike a miracle
  • Severity of case is according to how close to the
    brain the tic isdeath is rare
  • Causitve agent Dermacentor andersoni

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WHOOPING COUGH bacteria
  • Causitive agent Bordetella pertussis, a small,
    nonmotile, gram negative coccobacillus, it is an
    obligate aerobe.
  • The organisms does not invade tissues, but rather
    attaches to the cilia in the trachea and impedes
    their action, allowing mucus to accumulate.
  • It primarily affects children and is quite severe

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  • Symptoms initial stage (catarrhal stage) similar
    to common cold, the paraoxysmal stage is
    characterized with persistent coughs so violent
    that it can break ribs, gasping for air between
    coughs causes a whooping sound, and occurs
    several times a day for 1-6 weeks.
  • The Covalescence stage may last for months.
  • This is a very long duration for a respiratory
    infection, symptoms include high white blood cell
    count with diagnosis made from cultured throat
    swabs.

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  • Transmission is by inhaling pathogens expelled by
    coughing of infected patientMild case requires
    no specific treatment
  • Severe cases are treated with Tetracyclines and
    chloramphenicol..but only render the patient
    uncontagious
  • Vaccines exist but have considerable safety
    concerns (3.2 in 1 million result in neurological
    damage)

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INFLUENZA virus
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  • Caused one of the worst plagues ever to afflict
    humankind in 1918 (Spanish flu also called Swine
    flu 40 million dead within months).It is
    pandemic
  • So desperate the situation that Chicago police
    arrested people for sneezing in public and San
    Francisco required people to wear surgical masks
    over their mouths and noses in pubic violators
    were arrested

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  • 1957 and 1968 had milder epidemics but
    Virologist are scared that before long another
    superflu will emerge saying we are already
    overdue
  • Influenza does keep reemerging (reason for flu
    shot each year)( only AIDS virus mutates faster
    that the Influenza virusboth being classified as
    RNA viruses)

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  • If the same flu strain appeared each year we
    would develop an immunity to it
  • thus it mutates by changing its viral coat ever
    so slightly under a microscope it looks like a
    pasta salad with twists of macaroni entwined with
    one another ( 8 twisted segments in all)

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  • Mutation is due to its ability to enter humans,
    pigs and ducks ( thriving in the digestive tract
    and allowing a mixing and blending of different
    strains.what emerges is a new strain each year)
  • If the recombinant strain that is made is capable
    of infecting and causing illness in humans, a new
    pandemic looms over the horizon

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  • Solution keep ducks and pigs and humans away
    from one another as much as possible If
    different strains are not given the opportunity
    to co-infect a host, no superflu can emerge
  • However in Asian countries hens are hung in
    cages above pigs, which feed on the hen
    droppings, the pig feces are used to fertilize
    fish ponds where ducks swim drink and release
    their waste the last few flu strains have been
    Hong Kong flu, Shanghai flu and Singapore flu
    Luckily there has been no epidemic strain since
    1968.

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HANTAVIRUS
  • 1950s It was known as Korean hemorrhagic fever,
    later renamed hemorrhagic fever with renal
    syndrome
  • Was first discovered in the lung tissue of its
    natural host, the striped field mouse, in which
    it causes no illness
  • Kidney involvement seemed to be a hallmark of the
    disease.
  • When rats were tested in Baltimore, Philadelphia,
    New Orleans, New York and San Francisco the Seoul
    Korea

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  • Hantavirus turned up everywhere (1980 due to
    importing goods)
  • The American variety of hantavirus is a more
    deadly and silent killer, taking its toll
    unnoticed until late 1980s.
  • It has been confirmed in cases of hypertension
    and chronic kidney failure at a frequency 5X
    greater than the general public.

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  • 1993 a hot hantavirus struck a Navajo
    reservation in New Mexico a Navajo Indian passed
    away 5 days after his bride to be died both
    suffered mild flulike symptoms, then suffered
    severe respiratory distressOver a dozen more
    cases followed.
  • One patient sat up in bed in the morning talking
    and eating breakfast was on a respirator by
    afternoon and was dead that night.

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  • Prevention Control of rodent population, wear
    mask when doing spring cleaning in garages or
    attics if mouse droppings are present.birds
    possible are carriers of hanta as well
  • Treatment poor but a vaccine against certain
    strains does exist

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PLAGUE BACTERIAL
  • Also called Black Death due to the characteristic
    blackish areas of skin caused by hemorrhages

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  • 14th century ¼ total population in Europe died of
    Plague
  • Causitive agent is Yersinia pestis, a gram
    negative rod shaped bacteria transmitted from one
    rat to another by the rat flea Xenopsylla cheopis
  • Is endemic in wild rodents especially ground
    squirrels, prairie dogs and chipmunks with the
    number of plague cases reported in the USA
    increasing
  • If the host dies, the rat flea seeks a
    replacementanother rodent or a human

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  • Virulence is due to the ability of the bacteria
    to survive and proliferate inside phagocytic
    cells rather than being destroyed.
  • Symptoms lymph nodes in groin and armpit become
    enlarged (swellings called buboes reason for name
    bubonic plague), fever develops mortality rate
    50-75 if untreated death within one week

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  • Particular danger is if the bacteria enters the
    blood and lungs (pneumonic plague) mortality
    rate 100, even today this disease can rarely be
    controlled if not identified within 12-15 hours
    of onset of fever.death usually within 3 days
    high likelihood of airborne infections from
    infected person
  • Diagnosis is by a fluorescent-antibody testno
    vaccines are available except for persons likely
    to come in contact with infected fleas
    Prevention control rat-based population via
    sanitation

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IN CONCLUSION
  • A wise man should consider that health is the
    greatest of human blessings, and learn how by his
    own thought to derive benefit from his illness
    Hippocrates

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  • Fifty million people drink unfiltered water in
    America.
  • Not surprisingly, waterborne microbes such as
    rotavirus, the worlds leading cause of diarrhea
    continue to infect, sicken and kill.
  • Each year thousands of people die in the USA from
    infections by the familiar foodborne bacteria,
    salmonella and shigella.
  • Tuberculosis and AIDs are also on the rise in the
    USA, Canada and Europe.

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  • Jet travel has brought the human population(all 6
    million ) together.
  • It creates a melting pot for pathogens and for
    disease transmission.
  • The extremely virulent viruses emerging from the
    rain forests (Ebola, Marburg, Lassa) are no
    longer isolated from the population.
  • The resurgence of tuberculosis has reminded us
    that diseases once vanquished can return with a
    vengeance

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  • To this point we have been blessed.
  • The most common yet potentially dangerous
    bacterial infections (Step and Staph)remain
    susceptible to at least one antibiotic
    (vancomycin) and the most virulent or most lethal
    infections (Ebola, AIDS, and Marburg) are not
    easily transmitted.

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But what if common pathogens become resistant to
all antibiotics?
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What if AIDS or Ebola become airborne and easily
spread as the flue or common cold?
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Given the conditions that exist today, it is a
scary thought.
  • There is little doubt that the fourth
    horsemanpestilencehas saddled up and is
    charging at us.

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The fight against pathogens is never over.
  • To quote one epidemiologist We are all in it
    together

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AND THE BATTLE CONTINUES!!!!!!
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