UNIT 9: DISEASES AND DISORDERS:

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UNIT 9 DISEASES AND DISORDERS

• An infection occurs when living agents enter
  tissue, multiply there and damage the tissue.

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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)

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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 .

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• 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.

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• 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)

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

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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

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Impetigo is one disease caused by Strep infections
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• 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.

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necrotizing fasciitis
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• 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)

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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

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• 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)

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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.

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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) .

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

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• 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

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Ali Maow Maalin
The last known case of wild smallpox occurred in
Somalia in 1977
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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)

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• 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)

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• 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.

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• 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

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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.

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• 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

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Koplike patches indicating measles
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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.

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• 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.

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Scabies
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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)

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• 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.

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• Ring worms

• Athletes foot

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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.

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Thrush
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CONTATGIOUS CONJUNCTIVITIS pinkeye bacteria

• Caused by Hemophilus aegytius, and is transmitted
  by hand contact or by flies.
• Treatment topical application of antibiotics
  (vary)

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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.

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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

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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

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• 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.

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Tetanus
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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.

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• 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

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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)

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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

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• 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

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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

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• 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)

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Polio
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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)

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• 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

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• 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

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Rabies
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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.

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African sleeping sickness
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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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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

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• 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

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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

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KURU AND MAD COW DISEASE

• Kuru occurs in isolated groups of cannibals who
  eat brains.

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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

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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.

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• 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.

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• 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

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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

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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

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• 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

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• 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

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• 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

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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

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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

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HOT VIRUS

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

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VIRAL HEMORRAGIC FEVERS (MARBURG/EBOLA
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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

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• 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

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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.

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• 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

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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

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• 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

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• 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!!!!!!