Upper respiratory system
- nasal cavity - incoming air is filtered by mucus (traps dust particles) and cilia of columnar epithelial cells (move the particles to the throat for elimination) - called the mucociliary escalator or defense.
- pharynx - extends from the internal nares
Lower respiratory system
- larynx (voice box) - mucous membranes composed of ciliated columnar epithelial cells.
- trachea (windpipe) - mucous membranes composed of ciliated columnar epithelial cells; trachea is supported by hyaline cartilage rings.
- bronchi - trachea divides in
Respiratory system defenses
- Defenses: mucociliary defenses in upper respiratory system, larynx, trachea, & bronchi; macrophages in the bronchioles & alveoli; IgA (antibody) protects mucous membranes.
Respiratory system normal flora
- Normal Flora - includes species of streptococci, lactobacilli, & some Gram negatives in the upper respiratory system; the lower respiratory system (as well as the sinuses & middle ear) is normally sterile
Rhinitis
nasal inflammation; most common of all respiratory syndromes.
Adenoiditis
infection of adenoid tonsil
Pharyngitis
called tonsillitis if tonsils are primarily infected; symptoms include sore throat, sometimes fever, throat may be covered by a milky white exudate, ulcers, blisters, grayish membrane.
Sinusitis
sinuses fill with fluid & become infected.
Otitis media
middle ear infection; middle ear fills with fluid & becomes infected.
Epiglotitis
infection of the epiglottis; can cause the epiglottis to swell to many times its normal size; can cut off respiration and cause sudden death; on rare occasions laryngitis (infection of the larynx) & laryngotracheobronchitis (croup - produces a barking cou
Bronchitis
produces a thick, infected mucous; cough brings up infected phlegm; fever is another symptom; complete obstruction does not occur because the bronchi are so numerous.
Bronchiolitis
inflammation of bronchioles; air can enter, but has difficulty getting out; clinical signs include wheezing (musical noise heard during expiration) & tachypnea (rapid breathing).
Pneumonia
infection of the lungs, with fluid & microbes replacing the air that normally fills the alveoli; normal gas exchange cannot take place; clinical signs include fever, trachyapnea, labored breathing, & a cough that may produce infected secretions; if pneumo
Streptococcus pyogenes (Upper respiratory infections)
(Pharyngitis, Scarletina, Impetigo, Rheumatic Fever, Septicemia, PANDAS)
- G(+) cocci; pyogenes means "pus forming"; catalase negative (don't bubble when hydrogen peroxide is added); beta hemolytic; member of the Group A Streps (GAS); also referred to as
Pharyngitis
(strep throat) - transmitted by respiratory droplets or contaminated food/drink; clinical signs: severe sore throat, fever, chills, headache, inflamed pharynx, tender lymph nodes in neck; whitish exudate on tonsils; diagnosis: latex agglutination kit that
Scarlet fever [Scarlatina]
some strains produce an erythrogenic exotoxin; the toxin kills cells and causes intense inflammation; was once a life-threatening illness; the term scarlatina may be used interchangeably with scarlet fever, though it is most often used to indicate the les
Septicemia
bacteria spread to into the blood stream.
Rheumatic fever
autoimmune disorder; occurs after the strep throat infection is over (postinfection complication) or if a strep throat infection is left untreated; causes inflammation of joints, skin, brain, heart valves (endocarditis); leading cause of heart disease amo
PANDAS
[Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections] - describes a subset of children who have Obsessive Compulsive Disorder (OCD) and/or tic disorders such as Tourette's Syndrome, and in whom symptoms typically worse
Streptococcus pneumoniae (Upper respiratory infections)
(Otitis Media, Sinusitis, Pneumococcal Pneumonia, Meningitis, etc.)
- G(+), diplococci or chains; catalase negative; alpha hemolysis on BAP; optochin sensitive
- normal flora of upper respiratory tract
- capsule is critical factor in virulence
- Most comm
Haemophilus influenzae (Upper respiratory infections)
(Epiglottitis, Sinusitis, Otitis Media, Meningitis, Cellulitis, Conjunctivitis)
- G(-) rod
- needs a growth factor present in human red blood cells - hence the name Haemophilus ("blood loving")
- once thought to cause influenza - IT DOES NOT CAUSE INFLUEN
Epiglottitis
caused by H. influenzae type B (encapsulated strain) - adults produce Ab's, but young children are at risk; ampicillin not effective due to plasmid-borne antibiotic resistance; conjugate vaccine (Hib) now available; babies are routinely immunized against
Otitis media & sinusitis
caused by nonencapsulated strains (haemopholus influenzae); 2nd leading cause in children
Moraxella catarrhalis (Upper respiratory infections)
(Otitis Media, Sinusitis, Bronchitis, Pneumonia)
- G(-) diplococci
- Aerobic
- Other members of this genus are more rod shaped are rarely cause human disease
- Usually produce beta-lactamase, making them resistant to penicillins and cephalosporins
- Norma
Corynebacterium diphtheriae [Diptheria](Upper respiratory infections)
- Disease: diphtheria
- G(+) irregular rod (club shaped, but no endospore formation); look like Chinese letters
- produce an exotoxin; gene for exotoxin is carried by a temperate bacteriophage, so only strains infected by this virus can produce toxin & ca
Rhinoviruses (Common Cold)
- naked RNA viruses
- named for portal of entry - rhino means "nose"
- primary cause of common cold - causes 1/4 to 1/2 of colds.
- about 100 different serotypes (have different antigens in capsids), with new types continuing to be identified.
- Common Co
Coronaviruses (Common Cold)
- named for prominent spikes in their envelope (corona = crown)
- enveloped RNA virus
- difficult to isolate in cell culture
- cause 10-15% of colds in adults (also cause pneumonia & intestinal infections).
Streptococcus pneumoniae (Lower respiratory infections)
(Pneumococcal Pneumonia)
- G(+), diplococci or chains
- Catalase negative; alpha hemolysis on BAP; optochin sensitive
- normal flora of upper respiratory tract
- capsule is critical factor in virulence
- Most common cause of otitis media and sinusitis in
Klebsiella pneumoniae (Lower respiratory infections)
(pneumonia)
- G(-) rods
- Lactose fermenter; IMViC results: - - + +, ornithine decarboxylase negative
- Enteric normal flora
- clinical syndrome: typical pneumonia (consolidated lobe); sputum compared to "red currant jelly"; more common in smokers/alcohol
Moraxella catarrhalis (Lower respiratory infections)
(Pneumonia)
- G(-) diplococci
- Aerobic
- Other members of this genus are more rod shaped are rarely cause human disease
- Usually produce beta-lactamase, making them resistant to penicillins and cephalosporins
- Normal flora of nasopharynx
- Can cause up
Mycoplasma pneumoniae (Lower respiratory infections)
(Primary Atypical Pneumonia or "Walking Pneumonia")
- lack a cell wall
- adhere to epithelial cells; do not invade deeper tissues
- grow slowly in lab
- grows in trachea; transmitted in respiratory droplets
- clinical syndromes: occurs most frequently in
Chlamydia psittaci (Lower respiratory infections)
(Ornithosis = Psittacosis = Parrot Fever)
- Chlamydia are obligate intracellular parasites; can only be cultured in lab in chick embryos; therefore, infections are usually diagnosed serologically.
- psittaci means "parrot"; ornithology is the study of bir
Coxiella burnetii (Lower respiratory infections)
(Q Fever)
- Rickettsia - obligate intracellular parasite
- "Q" stands for query or question (etiologic agent unknown for years)
- Reservoirs - mainly sheep, goats and cattle
- transmission - tick vector or humans become infected by inhaling the microbe fr
Legionella pneumophila (Lower respiratory infections)
(Legionellosis or Legionnaires' disease; Pontiac Fever)
- In 1976, 183 American Legion conventioneers in Philadelphia became ill with mysterious pneumonia.
- can live inside macrophages; multiply as an intracellular pathogen.
- transmission - lives in nat
Bordetella pertussis (Lower respiratory infections)
- G(-) coccobacillus; produces exotoxins
- pertussis means "intensive cough"
- transmission - respiratory droplets; highly contagious
- clinical syndrome - uncontrollable fits of violent coughing (paroxysms); sometimes patients cough so hard they break a
Mycobacterium tuberculosis (Lower respiratory infections)
- rod-shaped obligate aerobe; G(+); id. by Robert Koch
- waxy cell capsule; called "acid fast;" require special staining techniques; waxy capsule allows microbe to survive prolonged drying and resists digestion by lysozymes inside a phagocyte; can remain
Mycobacterium leprae (Lower respiratory infections)
(Hansen's Disease or Leprosy)
- intracellular in macrophages; acid fast G(+) rods like M. tuberculosis
- 2 forms of disease: 1.) tuberculoid - areas of skin lose pigment (hypopigmentation) and sensation; 2.) lepromatous - nodular form where a granulomatou
Bacillus anthracis (Lower respiratory infections)
(Inhalation or Respiratory Anthrax)
- G(+) rod; form endospores; facultative anaerobe
- Forms: inhalation (pulmonary or respiratory), cutaneous, gastrointestinal (rare from eating endospore-contaminated meat); over 95% of cases are the cutaneous form; cut
Influenza Virus (Respiratory Influenza or Flu)
- Orthomyxoviridae
- composed of 8 separate pieces of RNA; this and its ability to infect an already infected cell enables the virus to undergo genetic recombination (antigenic shift); this contributes to the virus's genetic variability & potential to cau
Parainfluenza virus (Croup)
- Paramyxoviridae
- some cause common cold
- transmission - respiratory droplets
- clinical syndrome - laryngotracheobronchitis causes the airway to narrow at and below the vocal cords; extremely severe cases can resemble epiglottitis, but the illness is
Respiratory Syncytial Virus [RSV] (Bronchiolitis Pneumonia)
- Paramyxoviridae
- infected respiratory tissues develop syncytia (plasma membranes fuse to form large, abnormal cells with multiple nuclei)
- most common cause of fatal lower respiratory infection in young children/infants (especially preemies).
- transm
Hantavirus (Hantavirus Pulmonary Syndrome or HPS)
- arboviruses; named for Hantaan River in North Korea
- Hantavirus Pulmonary Syndrome - appeared mysteriously in the early 1990's in the 4 Corners area of the American Southwest.
- transmission - virus occurs in the long-tailed deer mouse; the mice shed t
Coronavirus (Severe Acute Respiratory Syndrome) [SARS CoV]
- Novel Coronavirus
- Disease originated in China
- No clear pattern as far as who is more susceptible
- Transmission mostly by respiratory droplets, but fomites, etc. could also play a role
- Incubation is typically 2- 7 days, but could be shorter or lon
Coronavirus (Middle Eastern Respiratory Syndrome) [MERS CoV]
- Novel Coronavirus (different from SARS CoV) first reported in Sep 2012 in Saudi Arabia
- IP: about 12 days
- Transmission - As of August 22, 2013a bat reservoir has been implicated. Not yet found to be highly communicable between humans via respiratory
Measles Virus (Rubeola Measles)
- Paramyxoviridae
- one of most communicable diseases known
- virus is inhaled
- virus multiplies in respiratory tract, then spreads throughout the body, multiplying in lymphoid tissue
- virus fuses cells to one another - can be seen under the microscope
Mumps Virus (Mumps)
- Paramyxoviridae
- transmitted in saliva or respiratory secretions; enters a new host through the respiratory system
- infects salivary glands; swelling of glands results, along with mild pain and sometimes fever; sometimes enters bloodstream and infects
Rubella Virus (Rubella or German Measles, Congenital Rubella Syndrome)
- Paramyxoviridae; originally thought to be a milder form of rubeola measles, hence the name German measles.
- Transmission: respiratory droplets (not as communicable as measles or chickenpox); teratogen - important for mother to be vaccinated before she
Roseola Virus {Roseola: Exanthem subitum (sudden rash) or Roseola infantum (rose rash in infants]
- Herpesviridae
- Occurs in young children (usually infants)
- Sudden onset of fever of 103-106 for 2-3 days; rash begins as fever goes away (numerous pale pink, almond-shaped macules appear on trunk and neck); seizures occur in small percentage of childr
Human Parvovirus (Fifth's Disease)
- Human Parvovirus is not same virus that causes Parvo in dogs and cats!!
- Childhood numbered diseases: rubeola, scarlet fever, rubella, SSS (scalded skin syndrome), roseola, Fifth's disease
- Mild illness; some may be asymptomatic
- "Slapped cheek" rash
Varicella Zoster virus (Chicken pox & Shingles)
- Herpesviridae
- like herpes, this virus establishes a latent infection in nerve cells that can be reactivated later
- Symptoms: people infected for the first time develop a generalized infection called Varicella or chickenpox, that produces clear, fluid
Varicella Zoster virus [Shingles] (or called Herpes Zoster)
reactivation of a latent Varicella Zoster infection; usually brief, but can be painful; does not only occur in elderly with compromised immune systems
- Symptoms: first symptom of shingles is often extreme sensitivity or pain in a broad band on one side o
Variola virus (Smallpox)
- less communicable than measles, but very hardy
- eradication of disease was announced in 1980 (last case was seen in Somalia in 1977)
- Symptoms: severity of disease depends on strain; produces a high fever and a severe blistering rash, killing about ha
Epstein-Barr virus [EBV] (Infectious Mononucleosis = Mono = Kissing Disease)
- associated with lymphatic system; virus establishes a latent infection in B lymphocytes (will appear atypical on a blood smear (as a result of antigen stimulation, they become large and misshapen; the nucleus is also less clumped).
- Symptoms: fever, fa
Coxsackievirus (Hand-Foot-Mouth Disease)
- Enterovirus
- Causes a rash that most frequently affects the extremities but also can appear on the trunk and other areas of the body; oral vesicles and ulcers frequently occur
- Symptoms usually begin on the oral surface of cheeks and gums and sides of
Parts of the digestive system
oral cavity, esophagus, stomach, small intestine, large intestine (colon), associated structures (salivary glands, liver, pancreas)
Gastro-
stomach
entero-
small intestine
col-
colon, large intestine
Gastritis
inflammation of the stomach; causes pain and occasional bleeding
Gastroenteritis
diarrhea, nausea, vomiting, crampy abdominal pain; can be caused by viruses or bacterial enterotoxins; also caused by intoxications (toxins produced outside of the body in food and are then ingested)
Colitis
involves colon; involves significant cellular damage (unlike gastroenteritis); diarrhea contains blood and mucous; called enterocolitis (dysentery) if it involves both the colon and some of lower small intestine.
Dental caries
tooth decay, cavities
Periodontal disease or periodontitis
destruction of gum and bone tissue
Parotitis
infected parotid salivary glands (over jaw, below ear)
Hepatitis
liver damage; symptom is jaundice (the liver filter bilirubin out of the blood and secretes it into bile that is dumped into the small intestine; if the liver is not functioning, then bilirubin remains in the blood stream; bilirubin is a yellow pigment th
Food-borne intoxication
toxin is produced by bacteria in food and is then ingested; disease not caused by infection (bacteria multiplying inside the body); usually quick onset of disease symptoms; antitoxin may be required to treat disease (antibodies against toxin).
Guillain-Barre Syndrome
usually associated with a previous infectious condition (a viral respiratory condition or a viral/bacterial g.i. disease); has also occurred after a vaccination; result of immune system attaching the peripheral nervous system (PNS - nerves); causes tempor
Dental Caries [=Cavities] - Treponema denticola, Streptococcus mutans, Streptococcus sanguinis, Lactobacillus
- G(+) cocci in chains
- One of the most common diseases worldwide
- Mechanism of pathogenesis; What makes this strep cariogenic? Bacteria possess adhesins on its pili that allow it to cling firmly to tooth enamel; it produces a glucan mesh from sucrose (
Gingivitis & Periodontal Disease - Bacteroides gingivalis & other species
- Different bacterial species cause dental caries and gingivitis
- leading cause of tooth loss in adults; damages tissues that surround and support teeth; most infections affect the gingiva and then spread to periodontal structures
- linked to heart disea
The BIG FOUR
Shigella, Salmonella, Campylobacter, and Giardia (NOT a bacteria, this one's a protistan)
Shigellosis [=Bacillary Dysentery] - Shigella dystenteriae & other species
- G- bacillus; lactose & sucrose nonfermenter; glucose fermenter; no sulfur reduction, urease negative
- An infection, not a foodborne intoxication
- Clinical Signs - fever; enterocolitis (stools are streaked with blood and contain strings of mucous compo
Typhoid Fever - Salmonella enterica serotype Typhi (or referred to as S. typhi)
- G- bacillus; lactose & sucrose nonfermenter, glucose fermenter, sulfur reducer, urease negative
- A true infection, not a food-borne intoxication
- Clinical Signs - high fever (>104) continues for days or weeks; some develop rose spots (rash) on the tru
Salmonellosis - Salmonella enterica (also referred to as S. enteritidis & S. enterica serotype Typhimurium)
- G(-) bacillus; lactose & sucrose nonfermenter; glucose fermenter; produce H2S; urease negative
- A true infection, not a foodborne intoxication.
- Clinical Signs - diarrhea (can be bloody), abdominal cramps, fever, nausea, vomiting, can develop into sev
Campylobacteriosis - Campylobacter jejuni
- curved G(-) bacillus (vibrio), microaerophilic; not recognized until the 1970's because they are so difficult to cultivate in the lab.
- A true infection, not a foodborne intoxication
- Clinical Signs - I.P. 2-5 days; frequent episodes of bloody diarrhe
E. coli Traveler's Diarrhea ("Montezuma's Revenge"), Dysentery, Epidemic Diarrhea in Nurseries, Hemolytic Uremic Syndrome (HUS) - Escherichia coli
- G(-) bacillus, lactose & glucose fermenter; IMViC: + + - -
- Most abundant facultative anaerobe in large intestine of humans - part of normal flora; most strains are harmless; also important pathogen of urinary tract.
- A true infection, not a foodborne
Peptic ulcers - Helicobacter pylori
- G(-) bacillus; flagellated
- has only been known to be associated with ulcers since about 1993!
- How do the bacteria survive the HCL in stomach? The bacteria produce an enzyme that converts urea to ammonia, raising the pH in the cell's vicinity.
- New
Cholera - Vibrio cholerae
- short, curved G(-) bacillus (vibrio); flagellated
- An infection, not a foodborne intoxication
- Pandemics in the 18OO's led to the adoption of modern systems of sewage disposal and public sanitation; The current pandemic (#7) is caused by the El Tor st
Botulism - Clostridium botulinum
- G+ bacillus, endospore-former, strict anaerobe
- toxin production depends on a viral prophage; bo-tox is the most poisonous natural substance known (as little as .000005 micrograms can kill a mouse - one oz. would kill the entire U.S. population!
- Clas
Infant Botulism - Clostridium botulinum
- G+ bacillus, endospore-former, strict anaerobe
- disease first recognized in 1976
- An infection, not a food-borne intoxication - bacteria produce toxin while multiplying inside body
- Clinical Signs - infant becomes lethargic and loses the ability to s
Pseudomembranous colitis [= C. diff Diarrhea] - Clostridium difficile
- G+ bacillus, endospore former, strict anaerobe; found in normal flora of some people
- iatrogenic (antibiotic induced) diarrhea; antibiotics like clindamycin kill off normal flora, but C. difficile is resistant
- Infection, not a foodborne intoxication
Clostridium perfringens food poisoning - Clostridium perfringens
- G+ bacillus; endospore former; aerotolerant anaerobe
- Food-borne intoxication
- Clinical Signs - I.P. 8-16 hrs; duration 24-48 hours; mild gastroenteritis; diarrhea; illness lasts less than a day; seldom reported; noticeable illness occurs only if high
Bacillus cereus food poisoning [= Fried Rice Syndrome] - Bacillus cereus
- G+ bacillus; endospore former, aerobic
- Foodborne intoxication
- Clinical Signs - gastroenteritis is usually mild and brief; there are 2 forms of illness associated with 2 enterotoxins:
1) Diarrheal - more common in U.S.; symptoms mimic C. perfringens
Staph aureus food poisoning - Staphylococcus aureus
- G(+) cocci in clusters, catalase & coagulase positive, salt tolerant, mannitol fermentation positive; normal flora of skin
- Foodborne intoxication
- Can survive in foods with a high sugar or salt content
- Clinical Signs - I.P. 2-6 hours; vomiting & di
Listeriosis - Listeria monocytogenes
- Small G+ bacillus in short chains; may be mistaken for Streptococcus; catalase positive; psychrophilic, so will actually multiply at cold temps; can even survive freezing temp
- An infection, not foodborne intoxication.
- Now a leading cause of infectio
Gastrointestinal Anthrax - Bacillus anthracis
- G(+) rod; endospore former; facultative anaerobe
- Forms: inhalation (pulmonary or respiratory), cutaneous, gastrointestinal (rare from eating endospore-contaminated meat); over 95% of cases are the cutaneous form
- Mode of transmission for G.I. Anthrax
Rotavirus
- Symptoms: watery diarrhea, fever, vomiting, dehydration (sunken fontanel, dry mouth, absence of tears, decreased skin turgor, sunken eyes); most common cause of severe viral enteritis (watery diarrhea) among infants and young children; often called the
Norovirus Virus [= Norwalk Virus = "Winter Vomiting Bug"]
- Virus is named for a 1968 outbreak in Norwalk, Ohio
- Common "stomach bug" in U.S.; responsible for nearly half of all U.S. outbreaks of acute infectious nonbacterial enteritis
- affects older children and adults more often than infants or preschoolers;
Poliomyelitis - Poliovirus
- Caused by 3 strains of polioviruses (Types 1, 2, 3) that have an affinity for motor neurons of the spinal cord/brain.
- Clinical signs: High fever, back pain, and muscle spasms can occur. Most infections are asymptomatic, or mild and nonparalytic. In <
Hepatitis A - Hepatitis A Virus (HAV)
- RNA virus
- Clinical signs: include flu-like symptoms, malaise, nausea, diarrhea, abdominal pain, dark urine, and jaundice; jaundice is caused by impaired liver function (the liver normally filters out hemoglobin from worn out red blood cells and breaks
Hepatitis E - Hepatitis E Virus (HEV)
- Becoming more common
- Transmission - fecal/oral; contaminated water or food supplies have been implicated in major outbreaks; ingestion of raw or uncooked shellfish have been implicated; swine have been shown to be reservoirs; person-to-person transmis
When I am intoxicated I prefer to take a CAB.
[Clostridium perfringens, Bacillus cereus Staphylococcus aureus Clostridium botulinum]
Meningitis
Meningitis is an infection/inflammation of the meninges [membranes that cover brain & cord].
The Disease: Meningitis causes necrosis, clogging of blood vessels, increased pressure within the skull and spinal column from edema (swelling), decreased CSF cir
Bacterial meningitis
- Commonly caused by one of 3 types of bacteria [Haemophilus influenzae type B, Streptococcus pneumoniae, Neisseria meningitides], but can be caused by many other bacteria (ex. Listeria).
- Before the 1990's, Hib was the leading cause of meningitis. The H
Meningococcal Meningitis - Neisseria meningitidis
G(-) diplococci
causes 2000-3000 cases per year in the US
Mortality is 85% if untreated, but only 1% if treated
Organism colonizes nasopharynx, spread to blood, and to meninges
Cocci can invade all parts of body and cause endotoxin shock and death within
Haemophilus Meningitis - Hameophilus influenzae type B (Hib)
G(-) bacillus
once the leading cause of meningitis and mental retardation in children
humans are exposed to bacteria early in life and rapidly acquire immunity, so disease is rare in adults
almost always fatal if not treated (about 1/3 die even with treat
Pneumococcal Meningitis - Streptococcus pneumoniae
G(+) diplococci or chains; alpha hemolytic; optochin sensitive
organism spread via the blood from lungs, sinuses, and ear infections
Vaccines: Pneumovax (usually adults) & Prevnar (usually children
Aseptic Meningitis - Enterovirus, Mumps virus
unlike bacterial meningitis, which is always fatal if untreated, viral meningitis is usually self-limiting and nonfatal
can be caused by enteroviruses or mumps virus; enteroviruses are more common cause in the U.S. as many people have been vaccinated agai
Hansen's Disease (Leprosy) - Mycobacterium leprae
G(+) acid-fast bacilli like M. tuberculosis; intracellular in macrophages
2 forms of disease: 1.) tuberculoid - areas of skin lose pigment and sensation; 2.) lepromatous - nodular form where a granulomatous response causes enlarged, disfiguring skin lesio
Tetanus [= Lockjaw] - Clostridium tetani
G+ bacilli, strict anaerobe, endospore-forming
found in intestines of many animals; endospores from dirt are deposited deep in tissues (ex. puncture wound)
endospores germinate in anaerobic environment
tetanus neurotoxin effects release of inhibitory neur
Botulism - Clostridium botulinum
G+ bacillus, endospore-former, strict anaerobe
toxin production depends on a viral prophage; botox is the most poisonous natural substance known (as little as .000005 micrograms can kill a mouse - one oz. would kill the entire U.S. population!
A food-born
Infant Botulism - Clostridium botulinum
G+ bacillus, endospore-former, strict anaerobe
disease first recognized in 1976
An infection, not a food-borne intoxication - bacteria produce toxin while multiplying inside body
Clinical Signs - infant becomes lethargic and loses the ability to suck and
Equine Encephalitis (viral)
Encephaliltis is an infection/inflammation of the CNS
4 types (all caused by a different virus): Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), Venezuelan Equine Encephalitis (VEE), and St. Louis encephalitis (SLE). Named because th
West Nile Virus (viral)
Spread by the bite of a mosquito
Can infect people, horses, birds, and some other animals. Dead birds in an area may mean that West Nile virus is circulating between the birds and the mosquitoes in that area. Over 110 species of birds are known to have be
Rabies (viral)
rabies = "to rage"
Reservoirs - any mammal can be a reservoir! Most common in U.S.: raccoons (#1), skunks (#2), bats (#3), foxes (#4), cat (#5), cattle (#6), dogs (#7); there are even cases in horses and squirrels!. Globally, dogs are a major reservoir, b
PRION DISEASES OF THE NERVOUS SYSTEM
Prion Defined: infectious agent composed only of protein (no DNA or RNA!).
Includes Kuru and Creutzfeldt-Jakob Disease (CJD) of humans, mad cow disease, scrapie of sheep, and chronic wasting disease of elk and mule deer. These diseases are referred to col
Kuru ("Laughing Death")
Spread through breaks in the skin; occurred mainly in New Guinean women. Discovered that they prepared the bodies of the dead for cannibalistic consumption and smeared their own bodies with the raw flesh of the corpses. Since cannibalistic rites have been
Creutzfeldt Jakob Disease [CJD]
in most cases, no source of prions has been identified; there seems to be a genetic predisposition in some families; death occurs within one year of onset of symptoms; number of human cases is on the decline.
Mad Cow Disease
[bovine spongioform encephalitis = sponge brain] - reached a peak in Britain in the early 1990's; spread through the practice of boiling down animal remains for livestock feed. The US has banned the import of British beef, cattle, and beef products. Canno
Chronic Wasting Disease
has been diagnosed in the U.S. in elk and mule deer.
Arthropod Vectors
Arthropods are invertebrates with jointed legs, segmented bodies, and a hardened, chitinous exoskeleton. They are not microbes, but serve as vectors for many microbial diseases; that is, they transmit disease between 2 hosts. Some are also reservoirs of i
Plague - Yersenia pestis
- G(-) coccobacilli
- zoonosis; spread from infected rodents (rats, squirrels, prairie dogs) to humans by fleas; in West Texas, prairie dogs are reservoirs; recent report in a dog in New Mexico and a cat in Colorado (June 2011) - pets could acquire bacter
Tularemia [=Rabbit Fever = Lawnmower Disease] - Francisella tularensis
- G(-) bacilli
- zoonosis; reservoir: cottontail rabbits and other animals (squirrels, rats, even in feral hogs!)
- number of causes rises during rabbit-hunting season
- first isolated in Tulare County, CA in 1911
- disease is an occupational hazard for t
Relapsing Fever - Borrelia recurrentis
- spirochete
- transmitted by ticks and human body and head lice
- lice are crushed and their body contents scratched into the skin; ticks transmit bacteria in their salivary secretions
- several days of high fever, respites, and shorter periods of fever
Lyme Disease - Borrelia burgdorferi
- spirochete
- transmitted by deer ticks and other ticks (Ixodes dammini); ticks won't transmit the disease until they engorged, which can take up to 48 hours
- white footed deer mouse is the main reservoir; white-tailed deer, dogs, etc. are also reservoi
Rickettsias
are obligate intracellular bacteria; they are pleomorphic in shape (can present as bacilli, cocci, or thread-like)
Endemic (murine) typhus - Rickettsia typhi
- murine refers to rats and mice; cats, dogs, opossums can also be reservoirs
- transmitted by fleas (fleas defecate while biting, infecting the humans)
- fever, chills, crushing headache, vomiting; rash - trunk to extremities; disease is self-limiting an
Epidemic typhus (classic or louseborne typhus) - Rickettsia prowazekii
- epidemics were halted with discovery of pesticide DDT during WWII
- transmitted by body lice (when a louse bites, it defecates; as victim scratches bite, they inoculate the microorganisms into the wound)
- fever and headache; rash starts on trunk and sp
Brill Zinsser Disease
(recurrence of epidemic typhus) - disease has milder symptoms, in shorter in duration, and often does not cause a skin rash; caused by reactivation of latent microorganisms harbored in lymph nodes.
Q Fever - Coxiella burnetii
- "Q" stands for query (etiologic agent unknown for years).
- transmission - tick vector or humans become infected by inhaling the microbe from infected animal placentas, feces, amniotic fluid, or milk (they can survive the pasteurization process).
- atyp
Rocky Mountain Spotted Fever - Rickettsia rickettsii
- transmission: transmitted to humans by dog ticks
- fever, headache, weakness; rash begins on hands and feet and progresses toward trunk (reverse of progression in typhus); rash is prominent on palms and soles; blood vessel damage cause hemorrhages throu
Rickettsial pox - Rickettsia akari
- transmission: transmitted by mites found on house mice
- disease is mild and vesicular lesions resemble those of chickenpox
- often misdiagnosed as chicken pox.
Yellow Fever - Yellow Fever virus
- monkeys are reservoirs of the disease
- transmitted to humans by mosquitoes
- many victims suffer severe liver damage and become jaundiced
- once caused epidemics in the U.S., but has been eradicted
Equine Encephalitis (viral) - EEEV, WEEV, VEEV, SLEV
- Encephalitis is an an inflammation of the CNS
- 4 types (all caused by a different virus): Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), Venezuelan Equine Encephalitis (VEE), and St. Louis encephalitis (SLE). Named because they i
Scalded Skin Syndrome [= SSS or scalded baby syndrome] - Staphylococcus aureus
- caused by exotoxins called exfoliatins; about 5% of S. aureus strains are lysogenized by bacteriophage (virus) that codes for this particular toxin
- toxins travel through bloodstream to the skin causing upper skin layers to separate and peel; lesions f
Folliculitis, Abscesses, Boils, Sty (infected eyelash) - Staphylococcus sp.
inflammation of hair follicles or glands; abscesses can be serious - size of a baseball!
Impetigo - Streptococcus pyogenes, Staphylococcus aureus
- caused by S. aureus or S. pyogenes
- highly contagious pyoderma (pus producing skin infection); honey brown colored, crusty scabs often on the face, but can be anywhere on the body
- occurs almost exclusively in children
- easily treated with penicillin
Cellulitis - Streptococcus pyogenes, Staphylococcus aureus
- most commonly S. pyogenes or S. aureus, but can also be caused by Haemophilus influenzae, etc.
- caused by fast-spreading infection in the dermis and in the subcutaneous tissues below
- symptoms include pain, tenderness, swelling, fever, lymphangitis (r
Scarlet Fever [=Scarlatina] - Streptococcus pyogenes
already discussed under respiratory system
- some strains produce an erythrogenic exotoxin that causes scarlet fever; the toxin kills cells and causes intense inflammation; was once a life-threatening illness; today's cases are mild (due to a decrease in
Acne - Propionibacterium acnes & others
caused by bacteria feeding on sebum (oil)
Conjunctivitis (pink eye)
- bacterial conjunctivitis is extremely contagious; can be caused by S. aureus, S. pyogenes, Haemophilus influenzae, Pseudomonas sp., Neisseria gonorrhoeae
- conjunctivitis is more commonly caused by viruses
- symptoms: dilated blood vessels, swollen eyel
Trachoma - Chlamydia trachomatis
- Also discussed under STD's
- trachoma means "pebbled or rough;" scarring of eyelids causes eyelashes to point inward
- leading cause of preventable blindness worldwide; uncommon in US.
- Transmission: touching infected genitals, perinatal transmission,
Burn infections
Pseudomonas aeruginosa & others
Gas Gangrene - Clostridium perfringens and other species
- aerotolerant anaerobes, endospore formers.
- often a mixed infection
- causes a "snap, crackle, and pop" sound in crepitant tissue (distorted tissue caused by gas bubbles).
Necrotizing fasciitis [=Flesh Eating Strep] - Streptococcus pyogenes
- usually Streptococcus pyogenes; less commonly S. aureus; other bacterial species as well.
- Examples of transmission: abdominal surgery, scratching a rash, giving birth vaginally, little cut on finger, rug burn, broken leg, chicken pox lesions, etc.; ba
Wound Botulism - Clostridium botulinum
- G+ bacillus, endospore-former, strict anaerobe
- Toxin production depends on a viral prophage; bo-tox is the most poisonous natural substance known (as little as .000005 micrograms can kill a mouse - one oz. would kill the entire U.S. population!
- Tran
Cutaneous Anthrax - Bacillus anthracis
- G(+) rod; form endospores; facultative anaerobe
- Forms: inhalation (pulmonary or respiratory), cutaneous, gastrointestinal; over 95% of cases are the cutaneous form. See other descriptions of inhalation anthrax respiratory system notes.
- Mode of Trans
Foot and Mouth Disease (FMD) = Hoof and Mouth
- NOT the same as hand, foot, and mouth disease in humans!
- severe, highly communicable viral disease of cattle, sheep, deer, and swine (not humans!);
- recent outbreaks in Europe; eradicated in the US in 1929
- symptoms: disease is characterized by feve
Molluscum Contagiosum - Molluscum Contagiosum virus
- A skin disease caused by the molluscum contagiosum virus (MCV) usually causing one or more small lesions/bumps.
- MCV is generally a benign infection and symptoms may self-resolve. MCV was once a disease primarily of children, but it has evolved to beco
Genital (Venereal) Warts or Condyloma - Human Papillomavirus
- all warts are caused by different strains of human papilloma viruses (HPV); researchers have identified > 100 strains of HPV; ~60 strains cause plantar warts on hands/feet; ~40 different strains cause genital warts and cancer; not all strains that cause
Understand anatomy of urogenital system:
- Urinary system: kidneys, ureters, bladder, urethra
- Reproductive system:
--- Female: external genitalia, vagina, uterus, fallopian tubes, ovaries
--- Male: testes, penis, glands (produce seminal fluid), specific ducts (vas deferens)
Urethritis
inflammation of urethra
Cystitis
bladder infections
Ureteritis
inflammation of ureter
Pyelonephritis
kidney infection
UTIs
- Diagnosis: urinalysis: look for presence of nitrates & proteins in urine
- Symptoms: dysuria (painful urination), frequent urination, cloudy/foul smelling urine, kidney pain, nausea, vomiting, fever
- Prevention: drink lots of water; urinate frequently;
TSS (Toxic Shock Syndrome) - Staphylococcus aureus
- incidence rose sharply in late 1970's; rise associated with new superabsorbent, but abrasive, tampons, which were left in vagina for long periods of time; tampons caused small tears in vaginal wall and provided appropriate conditions for bacteria to mul
Bacterial Vaginitis (B.V.) - Gardnerella vaginalis
- usually caused by opportunistic organisms that multiply when the normal vaginal microflora are disturbed by antibiotics or other factors (pregnancy, use of contraceptive pills, menopause, douching); has now been shown to also be transmitted sexually..
-
Syphillis - Treponema pallidum
- spirochete bacterium; difficult to isolate in patient
- std; can also be transmitted in saliva
- 3 disease stages: primary (genital chancres), secondary (rash can look like chicken pox or heat rash), tertiary (damage to all organs, death) - latent stage
Gonorhea [the "clap"] - Neisseria gonorrheae
- "flow of seed" a Greek physician in 130 AD mistook pus for semen
- G(-) diplococci; possess pili that allow them to attach to epithelial cells and to sperm; can survive in dried masses of pus for 6-7 weeks
- produce endotoxin that damages the reproducti
Nongonococcal Urethritis (NGU) - Chlamydia trachomatis
- "nongonococcal" means symptoms may be similar to gonorrhea, but it's not gonorrhea; symptoms are generally milder.
- prevalence is greater than gonorrhea/syphilis; the most common bacterial std's
- bacteria has an intracellular life cycle (bacteria ente
Genital (Venereal) warts or Condyloma - Human Papillomavirus
- all warts are caused by different strains of human papilloma viruses (HPV); researchers have identified > 100 strains of HPV; ~60 strains cause plantar warts on hands/feet; ~40 different strains cause genital warts and cancer; not all strains that cause
AIDS (Acquired Immune Deficiency Syndrome) - HIV Human Immunodeficiency Virus)
- About the virus: This virus is called a retrovirus (retro means backward). This virus uses the enzyme reverse transcriptase to make DNA from its RNA. This DNA can be integrated into the host cell's chromosome (now called a provirus). The provirus can st
Hepatitis B - Hepatitis B Virus (HBV)
- Partially double stranded DNA virus
- called "AIDS' Twin" and "serum hepatitis";
- Transmission: same as with HIV (body fluids); sexual contact, blood transfusions, re-use of contaminated needles & syringes, body piercings & tattoos, and vertical transm
Hepatitis D (HDV)
- RNA virus
- HDV is considered to a subviral satellite because it can propagate only in the presence of the hepatitis B virus (HBV). HDV uses the HBV surface antigen to form a capsid.
- Transmission of HDV can occur either via simultaneous infection with
Hepatitis C - Hepatitis C Virus (HCV)
- RNA virus
- not identified until 1989; blood, blood products (plasma, platelets, antibody), & organs not screened until 1992, so were a source of infection prior to this time!
- the most common blood-borne infection in the United States, affecting at le
Herpes - Herpes Virus
- herpes simplex type 1 - oral herpes; causes fever blisters or cold sores
- herpes simplex type 2 - genital herpes
- one of the most common STD's
- Oral can become genital and genital can become oral (usually due to oral sex).
- Latency is a hallmark of
Cytomegalic Inclusion Disease - Human cytomegalovirus (HCMV or jsut CMV)
- virus is a member Herpesviridae [also known as Human Herpesvirus 5]; establishes a latent (chronic) infection that can be reactivated
- infects between 50% and 80% of adults in the United States as indicated by the presence of antibodies in much of the
Ebola - Ebola Virus
- RNA enveloped "thread" virus; 5 subtypes (strains)
- Causes a severe hemorrhagic viral fever
- First recognized in 1976 in Zaire, Africa
- Transmission: direct contact with body fluids; possible respiratory transmission; nosocomial transmission dangerou