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115 Cards in this Set
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Hansen's Disease (Leprosy)
Mycobacterium lerprae |
G(+) acid fast, bacilli, intracellular in microphages
Tuberculoid: areas of skin lose pigmentation and sensation; destroys peripheral nervous tissues; likes cooler parts of body like nose, ears; leading; lack of sensation in affected areas; bone will be reabsorbed causing digits to become shorter; leonine facies (lions face); transmission by respir. droplets, shared beddin, clothing; only animal reserviors (armidillos in tx) |
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Tetanus (Lockjaw)
Clostridium tetani |
G(+) bacilli, strict anaerobe, endospore-forming; endospored from dirt are deposited deep in tissue; opposing muscles contract at the same time; make puncture wounds bleed to flush put sporesor flush with hydrogen peroxide; treatment is antitoxin
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Botulism
Clostridium botulinum |
G(+) baccili, endospore former, strict anaerobe; food born illness; flaccid paralysis, affects nervous system; transmission from non acid home canned products like herb inused oils; treatment antitoxin
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Infant botulism
Clostridium botulinum |
G(+) bacilli, endospore former; strict anaerobe; not food born intoxication; infant becomes lethargic and swallow or suck; floppy baby syndrom; transmissions feeding honey to babys; prevention no honey for infants under 12 months; treatment antitoxin
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Equine encephalitis
viral |
infect horses more often than humans; transmission from mosquito to bird back to mosquito to human, horse or other mammal; EEE most serious, VEE resembles flu; SLE occurs in late summer; treatment only allieviates
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West Nile Virus
virus |
Spread by bite of mosquito; can infect huma, horses, birds and some other animals; no symptoms or mild ones; risk is higher in those 50+
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Rabies
virus |
resivoir: dogs, cats, bats, foxes, coyotes, skinks, raccoons; bite from animal; virus replicatesin injured tissue and slowly migrates to nerves where reaches CNS; ime required for diease to appear is proportional to the length it is away from the brain; vaccination Rabavert
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Poliomyelitis: Polio virus
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3 strains; muscle spasms, spinal paralysis is most common form; transmission fecal oral routeand from pharyngeal secretions; virus is shed in feces; absence of animal resevoir; currently in india and africa; vaccines: salk vaccine injectable, inactivated with formalin; requires boosters and sabin vaccine oral, atenuated; provides longer lasting immunity but in a small number of patientshas become a virulent form
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Prion diseases
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infectuous agent composed only of protein (no dna or rna);includes Kuru and Creutzfeld-Jakob disease (of humans), mad cow disease, scrapies in sheep and chronic wasting disease of elk and mule deer refered to collectively as transmissible spongioform encephalopathies bc they give the brain a spongy appearance
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Kuru
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Spread through breaks in skin; occurred mainly in New Guinean women; ate the brain of their dead and smeared raw flesh of corpses; since these ritual stopped the disease disappeared
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Hansen's Disease (Leprosy)
Mycobacterium lerprae |
G(+) acid fast, bacilli, intracellular in microphages
Tuberculoid: areas of skin lose pigmentation and sensation; destroys peripheral nervous tissues; likes cooler parts of body like nose, ears; leading; lack of sensation in affected areas; bone will be reabsorbed causing digits to become shorter; leonine facies (lions face); transmission by respir. droplets, shared beddin, clothing; only animal reserviors (armidillos in tx) |
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Tetanus (Lockjaw)
Clostridium tetani |
G(+) bacilli, strict anaerobe, endospore-forming; endospored from dirt are deposited deep in tissue; opposing muscles contract at the same time; make puncture wounds bleed to flush put sporesor flush with hydrogen peroxide; treatment is antitoxin
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Botulism
Clostridium botulinum |
G(+) baccili, endospore former, strict anaerobe; food born illness; flaccid paralysis, affects nervous system; transmission from non acid home canned products like herb inused oils; treatment antitoxin
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Infant botulism
Clostridium botulinum |
G(+) bacilli, endospore former; strict anaerobe; not food born intoxication; infant becomes lethargic and swallow or suck; floppy baby syndrom; transmissions feeding honey to babys; prevention no honey for infants under 12 months; treatment antitoxin
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Equine encephalitis
viral |
infect horses more often than humans; transmission from mosquito to bird back to mosquito to human, horse or other mammal; EEE most serious, VEE resembles flu; SLE occurs in late summer; treatment only allieviates
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West Nile Virus
virus |
Spread by bite of mosquito; can infect huma, horses, birds and some other animals; no symptoms or mild ones; risk is higher in those 50+
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Rabies
virus |
resivoir: dogs, cats, bats, foxes, coyotes, skinks, raccoons; bite from animal; virus replicatesin injured tissue and slowly migrates to nerves where reaches CNS; ime required for diease to appear is proportional to the length it is away from the brain; vaccination Rabavert
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Poliomyelitis: Polio virus
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3 strains; muscle spasms, spinal paralysis is most common form; transmission fecal oral routeand from pharyngeal secretions; virus is shed in feces; absence of animal resevoir; currently in india and africa; vaccines: salk vaccine injectable, inactivated with formalin; requires boosters and sabin vaccine oral, atenuated; provides longer lasting immunity but in a small number of patientshas become a virulent form
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Prion diseases
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infectuous agent composed only of protein (no dna or rna);includes Kuru and Creutzfeld-Jakob disease (of humans), mad cow disease, scrapies in sheep and chronic wasting disease of elk and mule deer refered to collectively as transmissible spongioform encephalopathies bc they give the brain a spongy appearance
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Kuru
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"LAUGHING DEATH" Spread through breaks in skin; occurred mainly in New Guinean women; ate the brain of their dead and smeared raw flesh of corpses; since these ritual stopped the disease disappeared
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Creutzfeld Jakob disease (CJD)
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no source of prions identified in most cases ; there seems to be a genetic predisosition in some families; death occurs within one year of onset
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Mad Cow Disease
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bovine spongioform encephilitis; reached peak in britian in early 90's; spread through burning down animal remains for livestock feed; us banned import of british beef, cattle and beef products; if you have been to britian you cannot donate blood
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Chronic wasting disease
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been diagnosed in the US in elk and mle deer
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Meningococcal Meningitis
Neisseria meningitides |
G(-) diplococci; causes 2000-3000 cases per year in the USprganisms colonizes nasopharynx spread to blood and to meninges; cause endotoxin shock and death within hours; caleed Waterhouse-Frederichesen syndrome; vaccines: Menumone/Menactra; recent breakout in college have led to routine vaccines
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Haemohilus meningitis
Haemophilus influenzae type B |
G(-) bacillus, once leading cause of mental retardation; aquired immunity as child so rare in adults; vaccines Hib
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Pnemococcal Meningitis
Streptococcus pneumoniae |
G(+) diplococci or chains; alpha hemolyticl optochin sensitive; spead via blood from the lungs, sinuses, and ear infections; vaccines; pneumovax and prevnar
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Pharyngitis
Streptococcus pyogenes |
G(+) cocci; pyogenes means pus forming; catalase neg; beta hemolytic; transmitted by respiratory droplets or contaminated food/drink; whitish exudate on tonsils; diagnosis latex aggulation kit that detects Ag in throat swab
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Scarlet fever
Streptococcus pyogenes |
G(+) cocci; pyogenes means pus forming; catalase neg; beta hemolytic; fever kills cells and causes intense inflammation; small red bumps on neck and groin and then spread to other parts; feels like sand paper; Pastia's line-hyperpigmented areas, strawberry tongue
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Rheumatic fever
Streptococcus pyogenes |
G(+) cocci; pyogenes means pus forming; catalase neg; beta hemolytic; occurs after throat infection is over; causes inflammation of of joints, skin, brain, heart valves; leading cause of heart disease in kids in dev countriesbacteria have similar Ag to MH markers of the heart; white blood cells become sensitized with the bacterial Ag, then attacks the hearts cells; can be prevented if strp throat is treated within 10 days
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Otitis media, Sinusitis, Pneumococcal pneumonia, Meningitis
Streptococcus pneumoniae |
G(+) diplococci or chains; catalase negative; alpha hemolysis on BAP;optochin sensitive; normal flora of upper respiratory tract;
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Epiglottis
Haemophilus influenzae |
G(-) rod; needs growth factor presence in human red blood cells; "blood loving"; capsule protection; epiglottis caused by type B, young children are at risk, ampicillin not effective bc plasmid-borne antibiotic resistance; vaccine Hib;
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Otitis media and Sinusitis
Haemophilus influenzae |
G(-) rod; needs growth factor presence in human red blood cells; "blood loving"; capsule protection; caused by nonencapsulated strains; 2nd leading cause in children
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Meningitis
Haemophilus influenzae type B (encap) |
G(-) rod; needs growth factor presence in human red blood cells; "blood loving"; capsule protection; infection of the meninges; before the hib was the leading cause ofmeningitis and mental retardation
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Cellulitis
Haemophilus influenzae type B (encap) |
G(-) rod; needs growth factor presence in human red blood cells; "blood loving"; capsule protection; infection of the skin and subcutaneous tissues
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Diptheria
Corynebacterium diphtheriae |
G(+); irregular rod; looks like chinese letters; prduce exotoxin; gene for exotoxin is crried by a temperate bacteriophage, so only strains infected by this virus can produce toxins; transmission is respiratory droplets; bacteria is noninvasive but affected bc they absorb the toxin; signs dipther (leather hide); throat swells and becomes covered by a tough-graish pseudomembrane composed of dead human cells and mcrobes, swollen neck (bull neck)can obstruct airway and damage other organs with toxin
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Rhinoviruses (Common cold)
virus |
naked RNA virus; rhino means nose; primary cause of common cold; about 100 different serotypes; signs rhinorrhea
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Coronavirus (Common cold)
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prominent spikes in envelope (corona=crown) difficult to isolate in cell culture; also cause pneumonia ans intestinal infections
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Pneumococcal pneumonia
Streptococcus pneumonia |
G(+), diplococci or chiains; catalase neg, alpha hemolysis, optochin sensitive, capsulated; transmission is resp droplets; signstypical pneumonia bacteria in lungs trigger intense inflammatory response; leaky capillaries allow fluid blood cells and serum protein to flow into the alveoli filling them; xray lungs appear white; pneumococcal sepsis (when bacteria enter blood stream)particularly in patients with no spleen
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Pneumonia
Klebsiella pneumoniae |
G(-) rods; lactose fermentors; IMViC - - + +, ornithine decarboxylase neg; enteric, typical pneumoniae; sputnum red currant jelly
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Pneumonia
Moraxella catarrhalis |
G(-) diplococci, aerobic, other members are more rod shaped; causes bacteremia
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Primary Atypical Pneumonia
(Walking pneumonia) Mycoplsma pneumoniae |
lack cell wall; adhere to epithelial cells; dont invade deeper tissue; grows in trachea; trans resp dropet; signlow grade fever, persistant non productive cough; shows patchy pattern in chest x ray; treatment: tetracycline or erythromycin
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Ornithosis (Psittacosis or Parrot fever)
Chlamydia psittaci |
obligate intracellular parasites; only cultured in chick embryos; transmission microbe commonly infects all types of birds, usually not producing illness in bird; human infection primarily caused by inhalation of dust which is shed in large amounts in feces in birds; symptoms are atypical pneumonia and mental confusion; prevent by antibiotics in feed and antibiotic treatment of imported bird
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Q fever
Coxiella burnetii |
rickettsia; obligate intracellular parasite; qstands for query or question; transmission tick vactor or by inhaling the microbe form infected animal, placentas, feces, amniotic fluid or milk; cant be distinguished from mycoplasma pneumonia or parrot fever
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Legionellosis or Legionaires disease
Legionella pneumophila |
can live inside microphages; mult as intracellular pathogen; transmission in anturla and artificial water supply; survives heat and chlorination; infection aoccurs when waterborne microbes become aerosolized and are inhaled- water cooled air conditioning, plant ministers; signs xray show consolidation of entire lobe; smokers and alcoholics are susceptible; treatment resistant to penicllin and cepalosporins so use erythromicin
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Whooping cough
Bordetella pertusis |
G(-) coccobacillus; produces exotoxin; pertusis means intensive cough; transm through resp droplets; uncontrollable fitss of coughing (paroxysms) fit of cough ends in high pitched drawn in breath; vomiting may follow fits of coughing; cough persists for months; prevent with DTP and DTaP
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Tuberculosis "White death"
Mycobacterium tuberculosis |
rod shaped, obligate anaerobe; G(=); id by robert koch; waxy cell envelope, acid fast; leading killer among infectuous diseases; doesn't just infect lungs can infect lymphatic, genitourinary, skeletal and nervous system; transmited by resp droplets; primary infection microbes enter the lungs and are phagocytized by aveolar macrophages but are not killed, several weeks later t cells are activated, eliciting immune response and tuberucil Ag hypersensitivity; cellular immunity helps control the infection , hypersensitivity causes most of the damage associated with severe cases; the bacteria are isolated with nodules called tubercules or granulomas; bacteria can persist in tese bacteria for years the progressive primary infection occurs, cellular immunity fails to control the microbes and spread tp other parts of the body; look like seeds of grains scattered through out body; secondary infection walled of bacilli inside tubercules may escape; the ensuing hypersenstivity reaction can destroy the lungs; suffer chronic cough; xray consolidation in upper lobes; vaccine BCG vaccine made from attenuated M. bovis; not entirely reliable and not used in US; treatment for those with positive test but not disease treated with single drug for 1 year people with the disease recieve multiple drug therapy ; umber of cases in US is on the rise
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Anthrax
Bacillus anthracis |
G(+) rod, endospores; forms inhalation, cutaneous, gastrointestinl, and meningitis; over 95% are cutaneous; transmitted from contact ith infected animals or contaminated animal products; onces called wool sorters disease; recent outbreaks in Scotland and England assoc with herione use; may occur by eating meat contaminated, or inhaling endosporesnot communicable by resp droplets; symptoms of inhalation acute dyspneaand cyanosis; stidor may be present; spores are engulfed by WBC's once inside tey germinate into vegitative state and begin to divide, they break out of WBC's and infect the blood and release toxin, this toxin makes WBC's to release dangerous amounts of inflammatory response; cutaneous symptoms the spore is introduced to the site of a cut or abrasion; primary lesion occurs 1-7 days after infection of endospores, vesciles rupture, ulcer covered by black eschar, looks similar to a brown recluse bite; there is a vaccine but no name mentioned; penicillin used as treatment
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Infuenza virus
Respiratory influenza |
orthomyxoviridae; composed of 8 seperate oeices of RNA; different strains; A is avian or bird virus whoch has crossed into mammals, most severe and resp for pandemics; b common cold in children; c; symptoms tracheoronchitis person becomes prone to secondary infection bc coumnar epithelial cells are killed; animal reservior; antibiotics only prevent secondary infections; antiviral agents help speed up recovery; vaccine flumist
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Parainfluenza virus
Croup |
Paramyxoviridae; transmission by resp droplets; signs laryntracheobronchitis (causes airway to narrow at and below voal cords), common in toddlers, barking couh, make them cold to help constrict blood vessels; supportive care, no treatment
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Respiratory Synctial Virus
Bronchioliits pneumonia |
Paramyxoviridae; infected resp tissue dev synctia; most common cause of fatal resp illesses in toddlers/infants; transmit by resp droplet, hand to hand, nosocomial; wheezing heard during exhalation; worst inchild under 6 mo.;all preemies given Respigam or Synagis
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Hantavirus
Hantavirus Pulmonary |
arbovirusl; appeared mysteriously in 4 corners; transmitted from long tailed deer mouse, they shed the virus in urine and feces and saliva, come in contact by inhaling small particles; most cases result in death in 5 or 6 days caused by catastrophic lung failure; capillaries leak profusely an fluid fills the air space; natvie americans are at risk
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Hantavirus
Hantavirus Pulmonary |
arbovirusl; appeared mysteriously in 4 corners; transmitted from long tailed deer mouse, they shed the virus in urine and feces and saliva, come in contact by inhaling small particles; most cases result in death in 5 or 6 days caused by catastrophic lung failure; capillaries leak profusely an fluid fills the air space; natvie americans are at risk
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Measles Virus (Rubeola Measles)
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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 symptoms: fever 3-4 days before rash, cough, runny nose and eyes, conjunctivitis ("pink eye"), Koplik spots (red spots with bluish specks) appear in the mouth; rash appears first on face and gradually spreads downward to cover the entire body; rash is usually confluent on face and body; photophobia; ear infections, pneumonia, & encephalitis can occur part of MMR vaccine given at 15 months. |
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Mumps Virus (Mumps)
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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 other tissues; may infect the testes, causing sterility (inflammation called orchitis); in rare cases it infects the inner ear, causing deafness part of MMR (mumps, measles, rubella) vaccine given at 15 mo. |
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Rubella Virus (Rubella or German Measles)
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Paramyxoviridae
virus is inhaled incubation period is 2 weeks symptoms: mild fever, rash that lasts less than 3 days, swollen and tender, swollen lymph nodes (lymphadenopathy); rash begins as distinct red spots on face and spreads to neck, trunk, and extremities; rash not as intensely red as Rubeola Measles; complications are rare not as communicable as measles or chickenpox infection during first 3 months of pregnancy can cause a miscarriage or birth defects part of MMR vaccine given at 15 months. |
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Roseola Virus {Roseola: Exanthem subitum (sudden rash) or Roseola infantum (rose rash in infants]
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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 children as a result of fever (febrile seizures) |
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Human Parvovirus (Fifth's Disease
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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 - red papules on cheeks coalesce in hours forming red, warm plaques; Net pattern erythema - fishnet-like pattern on extremities before or after facial rash; rash may be itchy Sore throat; possible low grade fever, but not always detected; malaise; lymphadenopathy (swollen lymph nodes) absent Most adults have had the disease as a child, but an adult who has not previously been infected can be infected and become ill, and develop a rash, or joint pain or swelling, or both. The joint symptoms usually resolve in a week or two, but they may last several months. Pregnant women – most adults are already immune, so there is usually no risk to the baby. If a woman becomes infected during pregnancy, parvovirus could cause the unborn baby to have severe anemia and the woman may have a miscarriage. This occurs in less than 5% of all pregnant women who are infected with parvovirus and occurs more commonly during the first half of pregnancy. A blood test can test antibody titer. |
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Varicella Zoster virus (Chicken pox & Shingles)
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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-filled blisters in batches for 2-4 days; usually starts on the trunk then spreads to face, arms, & legs; itches like crazy; blisters mature, break open, form a sore, and then crust over; pox will not all be at the same stage in development at the same time. Recovery is complete, but the virus remains latent in neurons and infection can be reactivated (see shingles below) Adults who come down with chickenpox can develop a life threatening viral pneumonia Chickenpox during pregnancy is dangerous to the fetus as is chickenpox during the first year of life before the immune system is functioning Prevention: Varivax - an active attenuated vaccine |
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Shingles (or called Herpes Zoster):
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Symptoms: first symptom of shingles is often extreme sensitivity or pain in a broad band on one side of the body. The sensation can be itching, tingling, burning, constant aching, or deep, shooting, or "lightning bolt" pain. Typically, 1-3 days after the pain starts, a rash with raised, red bumps and blisters erupts on the skin in the same distribution as the pain. They become pus-filled, then form scabs by 10-12 days. The rash disappears as the scabs fall off in the next 2-3 weeks, and scarring may result.
Treatment: Passive immunization with Varicella Zoster immune globulin (VZIG) greatly decreases the severity of chickenpox if administered within 3 days of exposure Prevention: Zostavax – attenuated vaccine recommended for people over the age of 50 to prevent shingles outbreaks. |
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Variola virus (Smallpox)
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Symptoms: severity of disease depends on strain; produces a high fever and a severe blistering rash, killing about half of its victims; pox are on hands and feet unlike chicken pox. Pox are dimpled (“belly button pox”); pox all at the same stage of development at the same time, unlike those in small pox
Prevention: Remember the story about Jenner discovering that cowpox could be used for a vaccination against smallpox? This was the first official vaccine (vacca = cow). The ancient Chinese made a powder from scabs of a person recovering from smallpox. They would then inhale the powder containing the weakened virus. They would come down with a mild case of smallpox that would prevent them from ever getting it again. A closely related poxvirus, Vaccinia virus, is now used for smallpox immunization (attenuated vaccine; some risk of Vaccinia infection from vaccine since it is live; cases where patient touch immunization site and then touches eyes, causing infection). |
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Epstein-Barr virus [EBV] (Infectious Mononucleosis = Mono = Kissing Disease)
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associated with lymphatic system; virus establishes a latent infection in B lymphocytes (will appear atypical on a blood smear
swollen cervical lymph nodes, enlarged spleen (spleenomegaly) and inflamed liver; throat may appear red and the tonsils covered with a whitish material (mono and severe streptococcal tonsillitis appear quite similar); the illness lasts 4-6 weeks; some infections are asymptomatic or extremely mild so go undiagnosed; diagnosis confirmed by serological tests EBV is one of the few viruses proved to be oncogenic - Burkitt's lymphoma – involves jaw and abdominal lymph nodes or digestive tract (in US it's primarily the latter); primarily involves B cells; also associated with nasopharyngeal carcinoma. |
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Coxsackievirus (Hand-Foot-Mouth Disease)
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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 tongue along with a low-grade fever of 100-102 F. The oral lesions can be painful, causing the affected individual to avoid eating. The lesions can last 7-10 days. HFM disease primarily affects children under 10 years of age, but adult infections can occur. It occurs worldwide, both in sporadic infections and in outbreaks; highest incidence in summer and early fall. The virus is shed in discharges from the nose and throat, in feces, and in aerosolized droplets. The viruses are shed in the throat for up to 4 weeks and in the stool for up to 12 weeks. Not the same as hoof and mouth disease in livestock!! |
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Dental Caries [=Cavities] - Streptococcus mutans, Streptococcus sanguis, Lactobacillus sp.
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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 (glucan mesh + bacteria + debris = dental plaque); it also produces lactic acid which damages dental enamel. Susceptibility – determined by consumption of sugar, genetic factors, lack of fluoride (makes enamel stronger) Prevention – future vaccine; introduce antibodies (passive immunization); modify mouth’s normal flora (introduce a species to compete with S. mutans) |
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Shigellosis [=Bacillary Dysentery] – Shigella dystenteriae
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G- bacillus; lactose & sucrose nonfermenter; glucose fermenter; no sulfur reduction, urease negative
An infection, not a foodborne intoxication enterocolitis (stools are streaked with blood and contain strings of mucous composed of many neutrophils); toxin may also contribute to watery diarrhea; toxin may affect other organs in body; causes convulsions in children; can be life threatening due to dehydration. Mechanism of pathogenesis/invasiveness – adhesin proteins on pili bind to human colon cells; colon cells phagocytize the bacteria; they are taken into the cytoplasm where they multiply and inhibit protein synthesis; bacteria then cause lysis of the host cells; produce patchy areas of destruction and inflammation called microabscesses; shiga toxin causes damage to blood vessels in intestinal wall and intense inflammation. Transmission – fecal –oral route (usually person to person, but can be by flies, food, water, fomites) Who? Children are more affected than adults; used to be known as asylum dysentery due to massive outbreaks in mental institutions; rare in the US, but important in the developing world Treatment – fluid therapy; antimicrobial therapy (antibiotics) |
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Typhoid Fever – Salmonella enterica serotype Typhi (or referred to as S. typhi)
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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 trunk; majority recover (about 10% die); some develop a chronic gallbladder infection that makes them persistent carriers Mechanism of pathogenesis/invasiveness – invasive (unlike Shigella); produces an endotoxin (high fevers) Transmission – fecal-oral route (not from poultry like S. enterica below) Treatment – antibiotics (chloramphenicol is drug of choice, but has toxic side effects) Typhoid Mary made this disease infamous! |
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Salmonellosis - Salmonella enterica
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G(-) bacillus; lactose & sucrose nonfermenter; glucose fermenter; produce H2S; urease negative
A true infection, not a foodborne intoxication. Clinical Signs – diarrhea, abdominal cramps, fever, nausea, vomiting, can develop into severe dehydration or systemic bloodborne infection; onset of illness is usually 1-2 days. Transmission – poultry, eggs, unpasteurized milk are the main source; estimated that about 1 in 4 chickens are contaminated; is also transmitted through exposure to reptiles, farm animals, and pets Prevention – using nonporous cutting boards; disinfecting cutting boards and cooking utensils; thoroughly cooking foods; washing hands. Treatment – antibiotic treatment of uncomplicated salmonellosis is medically inadvisable (treatment may cause them to become chronic carriers if bacteria are develop resistance); growing drug resistance among strains due to widespread use of antibiotics in animal feed. |
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Campylobacteriosis – Campylobacter jejuni
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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 diarrhea, abdominal pain, fever; major cause of diarrheal illness and dysentery; duration is 2-10 days; causes over 2 million illnesses in the U.S. each year; Salmonella and Campylobacter are the 2 most common causes of bacterial foodborne illness in the U.S. Mechanism of pathogenesis/invasiveness – destroys epithelial lining; produce a toxin and invade cells. Transmission – grows in intestinal tract of cattle, sheep, poultry, dogs, cats; human infection probably occurs from ingesting contaminated meat or milk (big one); direct person-to-person transmission may occur; has a low ID50. Treatment – usually non-life threatening and self-limiting (lasts about a week). |
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E. coli Traveler’s Diarrhea ("Montezuma's Revenge"), Dysentery, Epidemic Diarrhea in Nurseries, Hemolytic Uremic Syndrome (HUS) – Escherichia coli
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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 intoxication Diseases - Clinical signs – I.P. 1-8 days; may involve nausea, vomiting, diarrhea, bloating, malaise and abdominal pain; a typical case of t.d. causes 4-5 loose stools per day for 3-4 days; the toxin causes excessive water and electrolyte secretion; can invade intestinal epithelium and cause dysentery; deadly strain 0157:H7 can cause HUS in young children (destruction of rbc's releases hemoglobin; kidneys have work harder and may fail; 4-5% die); outbreaks of HUS have included undercooked hamburgers at Jack in the Box (1993), unpasteurized apple cider (1991), onions at Taco Bell (2006) Mechanism of pathogenesis – causes a dysentery syndrome almost identical to shigellosis; produce proteins that allow bacteria to invade human cells; its ”Shiga-like toxins” inhibit protein synthesis; not as virulent as Shigella. Prevention of t.d. – Some travelers take antibiotics prophylactically – not recommended (not effective and contributes to development of mutant strains); a better practice is to keep an antidiarrheal medicine available and use it only after symptoms appear. To be safe, drink the beer and ask for well done |
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Peptic ulcers – Helicobacteri pylori
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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 diagnostic test: use radioactive ammonia; bacteria will convert to urea that can be detected with a breath test Treatment – antibiotics!!!!! Can lead to gastric cancer People with type O blood are more susceptible |
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Cholera – Vibrio cholerae
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short, curved G(-) bacillus (vibrio); flagellated
An infection, not a foodborne intoxication Clinical Signs – dehydration from diarrhea (lose as much as a liter an hour); characteristic rice water stools (water flecked with small particles of mucous); dehydration is sudden & dramatic; a person can die in a day. Mechanism of pathogenesis – cholera exotoxin causes epithelial cells to secrete large quantities of chloride into intestine, causing water, sodium and other electrolytes to follow and leave body as diarrhea. Transmission – fecal-oral (contaminated water, infected shellfish, fish); can travel around oceans in algae. Prevention – sanitation; the manufacture and sale of the only licensed cholera vaccine (killed/inactivated) in the US has been discontinued because of brief and incomplete immunity; 2 recently developed vaccines for cholera are licensed and available in other countries; both appear to provide a somewhat better immunity and fewer side-effects than the previously available vaccine. Treatment – replacing lost fluid; administer water & electrolytes intravenously; tetracycline. |
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Botulism – Clostridium botulinum
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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! I.P. 12-72 hours; duration days to a month; flaccid paralysis (muscle weakness); muscle paralysis starts with the eye muscles; no fever; usual cause of death is respiratory paralysis; many cases are subclinical Mechanism of pathogenesis – produces a neurotoxin that affects the nervous system. Transmission – usually from improperly home-canned nonacid foods; herb-infused oils Treatment – antitoxin |
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Infant Botulism – Clostridium botulinum
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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 swallow (disease is sometimes called “floppy baby” syndrome); may be the cause of some infant deaths attributed to SIDS. Transmission – associated with feeding honey to infants (10% of honey contains botulism endospores; since baby has an underdeveloped immune system, the endospores turn into cells grow in the immature digestive tract of infants and cause botulism Prevention – do not give honey to a child under the age of 12 months. Treatment – antitoxin |
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Pseudomembranous colitis [= C. diff Diarrhea] – Clostridium difficile
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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 can be life-threatening often occurs in hospitals (nosocomial); replacing MRSA in some hospitals as the more prevalent nosocomial infection Treatment - vancomycin |
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Clostridium perfringens food poisoning – Clostridium perfringens
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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 numbers of spores are ingested. Transmission – lives in the g.i. tract of animals, humans, & is common in feces-rich soil; spores usually contaminate meat; when food is left unrefrigerated after cooking, spores germinate and new cells produce toxin which is then ingested. |
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Bacillus cereus food poisoning [= Fried Rice Syndrome] – Bacillus cereus
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G+ bacillus; endospore former
Foodborne intoxication Clinical Signs – gastroenteritis is usually mild and brief; there are 2 forms of illness associated with 2 enterotoxins; one form causes vomiting, the other causes diarrhea. Transmission – present in soil, water, g.i. tract of humans and animal, so often found in food; when food is left unrefrigerated after cooking, spores germinate and new cells produce enterotoxins which are then ingested. |
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Staph aureus food poisoning – Staphylococcus aureus
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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 (rapid onset); vomiting & diarrhea (“running at both ends”), crampy abdominal pain Mechanism of pathogenesis – enterotoxin (exotoxin); toxin can’t be destroyed by refrigeration/ cooking. Transmission – most frequently reported food poisoning in the U.S. – occurs in large outbreaks at picnics or social gathering; usually introduced into food from skin of person preparing it (part of normal skin flora); toxin is produced because food is not kept at proper temps Treatment – illness is usually brief and self-limiting, but antibiotics can be used if disease is severe; fluid replacement may be necessary. |
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Listeriosis – Listeria monocytogenes
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Small G+ bacillus in short chains; may be mistaken for Streptococcus; catalase positive; psychrophilic, so will actually multiply at cold temps
An infection, not foodborne intoxication. Now a leading cause of infection in kidney transplant patients. Teratogen - can cross the placenta and cause miscarriage and stillbirth; responsible for many cases of fetal damage Elderly or immunocompromised may develop a bacteremia and meningitis. Transmission – soft cheeses (ex. queso fresco a Mexican cheese made from unpasteurized milk), ready-to-eat meats (hotdogs, lunch meat, salami), unpasteurized milk, and vegetables |
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Rotavirus
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Common cause of viral enteritis (watery diarrhea) among infants and young children
number of cases rises during winter months in U.S. (helps to distinguish it from bacterial diarrheas) transmission is fecal-oral viral capsids resemble little wheels (rota) Each year nearly 500,000 children die from diarrheal disease caused by rotavirus, and another two million are hospitalized (usually in developing countries) Rotarix vaccine (attenuated) |
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Norwalk Virus [= Noro Virus]
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Virus is named for a 1968 outbreak in Norwalk, Ohio
affects older children and adults more often than infants or preschoolers outbreaks occur throughout the year characterized by 1-2 days of diarrhea, vomiting, or both; vomiting is the predominant symptom among children; can last as long as a week. immunity does not follow an attack New outbreaks usually occur where there is inadequate sanitation and food becomes contaminated with feces or vomit from infected people. investigations of foodborne illness have implicated oysters, salads, sandwiches, cakes, frosting, raspberries, drinking water, and ice has a low ID 50 (< 100 viral particles) |
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Poliomyelitis - Poliovirus
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Caused by 3 strains of polioviruses (Types 1, 2, 3) that have an affinity for motor neurons of the spinal cord/brain
. Most infections are inapparent, or mild and nonparylitic. In < 1% of cases, partial or complete paralysis of muscles can occur; nature and degree of paralysis depends on which neurons in the spinal cord and brain are damaged. Paralysis remaining after several months is permanent. Spinal paralysis is the most common form of paralytic poliomyelitis, affecting the lower extremities. Spinal polio is the most common form of paralytic poliomyelitis virus invasion causes inflammation of motor neurons; death of neurons can occur, leading to weakness of respective muscles innervated those neurons; muscles atrophy, becoming weak, floppy and poorly controlled, and finally completely paralyzed). Transmission – fecal-oral route and from pharyngeal secretions; once a danger in fecally contaminated swimming pools; virus is shed in feces! Absence of animal reservoirs plus availability of effective vaccines made health authorities in 1988 choose polio as the next disease to eradicate from the planet. Polio transmission is currently occurring primarily in India & Africa (still using OPV there). Vaccines: Salk vaccine (IPV) – injectable, inactivated (killed) with formalin; requires boosters Sabin vaccine (OPV) – oral, attenuated (live); provides longer-lasting immunity, but in a small number of cases (about 6 each year in the US), viruses have mutated into virulent viruses; no longer administer since risk of getting disease form vaccine is greater than getting it naturally from the environment |
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Hepatitis A – Hepatitis A Virus (HAV)
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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 it down into the yellow pigment bilirubin; bilirubin is normally deposited in bile and is eliminated from the body in feces; if liver function is impaired, bilirubin builds up in the blood stream); disease is usually self-limiting; chronic infections are rare – you can give blood after having Hep A. This virus does not cause liver cancer!
Transmission is fecal-oral; occurs most often in children and young adults; shellfish can be contaminated; outbreaks due to contaminated food in fast-food restaurants have been on the rise; also Mexican strawberries! Treatment: none, except for alleviating symptoms Havrix - inactivated vaccine Notice that Hepatits B, C, etc. are not listed here |
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Bacterial Vaginitis (B.V.) - Gardnerella vaginalis
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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..
Can be potentially dangerous to a fetus, but not to mother Diagnosis - clue cells (sloughed vaginal epithelial cells) have bacteria attached to them in distinctive patterns |
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Syphilis - Treponema pallidum
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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) has periodic latent stages (no symptoms) that make patients sometimes think that they do not have an STD called the “great imitator” because its symptoms mimic those of so many other diseases; heart valves, blood vessels, and meninges can be affected mental illness accompanies neural damage congenital syphilis occurs when bacteria cross the placenta from mother to baby – infant may show signs such as notched incisors ("Hutchinson’s teeth"), a perforated palate, a “saber tibia” (deformed shin bone), an aged face with a saddle-shaped nose less common than gonorrhea can be cured with antibiotics (penicillin & tetracycline) |
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Gonorrhea [the "clap"] - Neisseria gonorrhoeae
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“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 reproductive tract mucosa and produce proteases that destroy IgA antibody some people are asymptomatic; can be a carrier for 5-15 years postinfection contraceptive pills alter vaginal conditions in favor of gonococcal growth females can develop PID - pelvic inflammatory disease which can lead to sterility; bacteria infect the endometrium of the uterus and fallopian tubes; leading cause of infertility in the US; can also cause an ectopic pregnancy can also cause infections of pharynx, rectum, arthritis, blindness) treatable with antibiotics (penicillin & cipro); drug resistant strains have been identified in Hawaii and now California (both cephalosporin & quinolone resistance, but mostly to quinolones) – “as goes California, so goes the nation” silver nitrate administered to the eyes of newborns to prevent infections |
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Nongonococcal Urethritis (NGU) - Chlamydia trachomatis
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"nongonococcal" means symptoms may be similar to gonorrhea, but it's not gonorrhea; symptoms are generally milder.
prevalence is greater than gonorrhea/syphilis; one of the most common std's bacteria has an intracellular life cycle (bacteria enter host cells) disease may be difficult to detect (80% of women and 10% of men are asymptomatic) PID risk like gonorrhea infants can become infected when passing through birth canal; silver nitrate is ineffective |
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Genital Warts – Human Papilloma virus
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all warts are caused by different strains of human papilloma viruses (HPV); researchers have identified > 100 strains of HPV; some strains cause genital warts; plantar warts are caused by a different strains than genital warts
some warts are malignant (cancerous) – some strains associated with cervical cancer; grow on skin, genitals, respiratory tracts, oral cavity most cervical cancer is caused by HPV warts are more common in women genital warts are one of the most common STD's; many people are asymptomatic usually transmitted by direct contact (skin to skin) infection is lifelong; no cure for infected but warts can be removed - treated with cryotherapy (freezing) or caustic chemical agents virus is lysogenic; viral DNA inserts into the host cell’s chromosome and alters the DNA so that the host cell divides out of control Gardasil vaccine (genetically engineered) |
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AIDS (Acquired Immune Deficiency Syndrome) – HIV (Human Immunodeficiency Virus)
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This virus is called a retrovirus
to make DNA from its RNA. This DNA can be integrated into the host cell's chromosome provirus can stay in a latent stage which it is replicated along with host cell DNA, causing the host cell no damage. AZT (azidothymidine), which is used against HIV 3 major groups of HIV and 10 subtypes; most cases in U.S. caused by type I. Symptoms: infection typically causes flu-like symptoms, followed by an asymptomatic period of months or years during with the patient can transmit the disease; HIV specifically targets and destroys T helper cells and macrophage, thus affecting both the B cell and cytotoxic T cell responses, so person can die of a secondary infection; see page 520 for symptoms; most patients develop Kaposi’s sarcoma (caused by a herpes virus; tumors of blood vessels are seen as purplish spots on skin, but occur throughout the body) ARC (AIDS Related Complex) is a condition in which antibody tests are positive for HIV. Patients with ARC show the mild symptoms of HIV infection, which include enlarged lymph nodes, fatigue, night sweats, weight loss, and diarrhea. Transmission: sexual contact (all forms), sharing of needles, blood transfusions, mother to infant; development of a vaccine is difficult due to high mutation rate of virus First reported in 1980; thought that the virus could have jumped species (from primates to humans) AIDS has become the 5th leading cause of death among 25 to 44 yr. olds! |
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Hepatitis B – Hepatitis B Virus (HBV)
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DNA virus
called “AIDS’ Twin” and "serum hepatitis"; transmission is the same as with HIV (body fluids) chronic disease; can’t ever donate blood symptoms are similar to those of hep A, except that liver cells are frequently destroyed; some patients develop fulminant hepatitis, a condition of total liver failure about half of infected people are asymptomatic treatment relieves some symptoms, but does not cure disease; interferon treatment is used; some people need a liver transplant has been linked to liver cancer (increases chances of developing liver cancer by as much as 300 times) now part of routine infant vaccination. |
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Hepatitis C – Hepatitis C Virus (HCV)
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not identified until 1989
hepatitis C virus (HCV) usually spreads through contact with blood, most commonly by sharing needles and other equipment used to inject illegal drugs, but also through blood/organ donations; health care workers face a risk (although low, less than 2%) of infection from accidental needle sticks and other occupational exposures; virus can spread through sexual contact, but the risk is low; an infected mother can spread the virus to her baby at birth. the most common blood-borne infection in the United States, affecting at least 4 million people blood, blood products, & organs not screened until 1992 Acute Infection: occurs 2 weeks to 6 months after infection, usually is so mild that most people don't know they are sick. Older children and adults may develop some mild symptoms, such as fatigue, sore muscles, headache, widespread abdominal pain or pain that is concentrated in the upper right quadrant of the abdomen, nausea, dark urine or light (clay-colored) stools, loss of appetite or weight loss, aversion to some foods, particularly those that are fatty or fried or high in protein, jaundice. Chronic Infection: About 80% of people who become infected with HCV develop a chronic infection, which they often have for the rest of their lives. However, the majority of people with chronic HCV infection will not develop severe liver damage. Although it may take many years, up to 20% of people who have chronic HCV infection develop liver scarring (cirrhosis). Of these people, 1% to 4% also develop liver cancer. HCV infection is the most common reason for liver transplantation in the United States. Disease is severe in immunocompromised patients. Most people, especially young children, have no symptoms. If symptoms do develop, they may include: • Constant tiredness (fatigue) • A general sense of not feeling well (malaise) • Mild abdominal pain |
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Herpes – Herpes Virus
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herpes simplex type 1 – oral herpes; causes fever blisters or cold sores
herpes simplex type 2 – genital herpes Oral can become genital and genital can become oral (usually due to oral sex). Latency is a hallmark of herpes infections. More than 80% of the adult population worldwide harbors these viruses, but only a small proportion experience recurrent infections. Within 2 weeks of an active infection, viruses travel via sensory neurons to ganglia, where they become latent. They can be activated by fever, UV, stress, hormone imbalance, menstrual bleeding, trauma, diet, etc. When reactivated, virus moves along neuron to the epithelial cells, where it replicates and causes lesion. Neonatal herpes – babies become infected when passing through birth canal; rare, but can become infected in utero; infected neonates usually have central nervous system damage and die within 10 days. Disease can affect mucous membranes of mouth, eyes, lungs (herpes pneumonia); can also affect skin in places other than the mouth and genitals; a herpetic whitlow is a lesion on a finger that can result from exposure to oral, ocular, or genital herpes lesions. Treatment: cannot eradicate virus, but acyclovir can reduce reoccurrence of lesions. |
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Cytomegalic Inclusion Disease - Cytomegalovirus (CMV)
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virus is a member of the herpesvirus group
establishes a latent infection that can be reactivated; infected cells swell and develop inclusion bodies usually transmitted sexually, but also by the exchange of saliva and infected blood infection in adults & healthy children is usually asymptomatic; may a cause brief, mononucleosis-like illness can cause stillbirths, spontaneous abortions, birth defects causes systemic infections in AIDS patients |
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Ebola - Ebola Virus
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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 dangerous; monkeys a probable reservoir ID50 is less than 10 in primates IP: 2-21 days No cure or treatments Ebola Zaire strain has an 88% mortality rate |
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Plague – Yersenia pestis
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G(-) coccobacilli
zoonosis; spread from infected rodents to humans by fleas; in West Texas, prairie dogs are reservoirs; pneumonic plague can be spread between humans via respiratory droplets Bacteria clump together in the flea, blocking the digestive tract and driving the flea into a feeding frenzy. Two distinct forms of plague occur in human populations: 1. Bubonic plague occurs within a week of being bitten by an infected flea. Multiplication of the bacteria produces the characteristic "bubo" (swollen, painful lymph node especially in axillary region and groin). Bacteremia (blood infection) follows, causing death in about 50-75% of those infected if not treated. Hemorrhages turn skin black (“Black Death”) 2. Pneumonic plague occurs under crowded conditions when contaminated respiratory droplets expelled by infected persons are directly inhaled by another person. This form is characterized by a shorter incubation period and greater mortality (90%); can develop from bubonic plague if bacteria enter the blood and travel to the lungs; extremely communicable! Bioterrorism – in WWII the Japanese dropped infected fleas on China Ring around the rosie, A pocket full of posie. Ashes, Ashes, We all fall down. |
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Tularemia [=Rabbit Fever = Lawnmower Disease] - Francisella tularensis
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G(-) bacillus
zoonosis; reservoir: usually cottontail rabbits and other animals number of causes rises during rabbit-hunting season first isolated in Tulare County, CA in 1911; low incidence in US disease is an occupational hazard for taxidermists transmission: multiple transmission routes: parenteral through breaks in skin, bite from arthropod vector (tick, deer fly), inhalation of aerosols during skinning, consumption of contaminated meat; capable of surviving outside of a mammalian host for weeks at a time and has been found in water, grassland, and haystacks - aerosols containing the bacteria may be generated by disturbing carcasses due to brushcutting or lawn mowing (think about road kill rabbits) clinical signs: fever, severe headache, and buboes; one form can lead to a septicemia that resembles typhoid fever prevention: vaccine does exist but frequent boosters are required |
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Lyme Disease - Borrelia burgdorferi
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spirochete
transmitted by deer ticks and other ticks (Ixodes dammini) white footed deer mouse is the main reservoir; white-tailed deer, dogs, etc. are also reservoirs develop flu-like symptoms rash erythema chronicum migrans, which characterizes the disease (“bull’s-eye” rash – concentric rings around initial site of tick bite) other symptoms include arthritis, myocarditis, etc. often misdiagnosed there is a vaccine for dogs treat with antibiotics |
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Relapsing Fever – Borrelia recurrentis
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spirochete bacteria
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 due to changes in organisms’ antigens can cross placenta treat with antibiotics |
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Endemic (murine) typhus – Rickettsia sp.
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murine refers to rats and mice
transmitted by fleas (fleas defecate while biting, infecting the humans) fever, chills, crushing headache; rash – trunk to extremities; disease is self-limiting and lasts about 2 weeks if untreated; mortality is low. does occur in Texas; some cases recently in Austin |
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Epidemic typhus (classic or louseborne typhus) – Rickettsia sp.
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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 spreads to extremities (rarely affects palms or soles); mortality can range to 40% if untreated vaccine is available treat with antibiotics;. |
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Q Fever - Coxiella burnetii
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"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). atypical pneumonia; can't be distinguished clinically from mycoplasmal pneumonia or parrot fever; rare disease; rarely causes death. |
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Rocky Mountain Spotted Fever - Rickettsia rickettsii
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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 throughout the body treat with antibiotics prevalence not high in Rocky Mts. |
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Yellow Fever – Yellow Fever virus
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monkeys are reservoirs of the disease
transmitted to humans by mosquitoes many victims suffer severe liver damage and become jaundic |
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Equine Encephalitis (viral) – EEEV, WEEV, VEEV, SLEV
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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 infect horses more often than humans. Transmission – usually from a mosquito to a bird, back to a mosquito, and to a horse, human, or other mammal. Clinical Signs – fever, headache; convulsions sometimes occur. EEE is the most serious (causes severe necrotizing infection of the brain). VEE resembles the flu in humans. SLE occurs in late summer epidemics about every 10 years and is severe in elderly patients. Treatment only alleviates symptoms. Vaccines are available for horses, but are not used on humans for fear of inducing a virulent form of the disease. |
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West Nile Virus
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Transmission: 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. There is no evidence to suggest that West Nile virus can be spread from person to person or from animal to person. As of Aug. 13, 2002 there have 145 confirmed cases in the U.S. and 8 deaths. Vaccination against encephalitis (EEE, WEE, VEE) does not provide immunity to WNV. First case confirmed in 1999. Most people who become infected with West Nile virus will have either no symptoms or only mild ones. On rare occasions, West Nile virus infection can result in a severe and sometimes fatal illness known as West Nile encephalitis (an inflammation of the brain). The risk of severe disease is higher for persons 50 years of age and older. Symptoms include fever, headache, and body aches, occasionally with skin rash and swollen lymph glands. More severe infection may be marked by headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. I.P. - usually 3 to 15 days. |
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Scalded Skin Syndrome [= SSS or scalded baby syndrome] – Staphylococcus aureus
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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 first appear around umbilical cord, axillary region, or inguinal region; patient is susceptible to secondary infections most common in infants high fever present; septicemia and death can occur S. aureus also causes TSS (Toxic Shock Syndrome; has been associated with tampon use), boils, sties, endocarditis, food poisoning (foodborne intoxication), etc |
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Impetigo - Streptococcus pyogenes, Staphylococcus aureus
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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 usually heals without scarring, but pigment can be permanently lost (hypopigmentation) |
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Cellulitis – Streptococcus pyogenes, Staphylococcus aureus
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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 (red streaks leading away from the area – result of inflammatory products being carried by the lymphatic system) |
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Scarlet Fever [=Scarlatiina] - Streptococcus pyogenes;
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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 virulence); small red bumps begin on neck and groin and then spread to rest of body; rash feels like sand paper; may peel after fading; patient may have hyperpigmented areas especially in creases - called Pastia's lines; patient may also have strawberry tongue (tongue is covered with white membrane that sloughs off after a few days, revealing a shiny red tongue with swollen papillae.
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Conjunctivitis (pink eye)
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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 eyelids; bacterial conjunctivitis is usually more pyogenic (pus) than viral |
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Trachoma - Chlamydia trachomatis
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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 |
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Hansen’s Disease (Leprosy) - Mycobacterium leprae
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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 lesions called lepromas; can involve the eyes; may cause thickening of the skin classic “leonine facies” (lion face). This is the only bacterium known to destroy peripheral nerve tissue; it “likes” cooler parts of body (nose, ears, fingers, etc.) Symptoms: Infected individuals will notice skin lesions in early stages, leading to paralysis or loss of sensation in those areas, Because of the lack of sensation in affected areas of the skin, people with leprosy often do not notice burns and injuries to their fingers and toes and fail to treat them. These injuries can then become infected with other types of bacteria that cause tissue damage. Gradually, damaged tissue and bone are resorbed by the body, causing the digits to become shorter. However, leprosy does not, as myth would have it, cause parts of the body to fall off. Blindness can occur as the disease advances. Incubation period can be up to 20 yrs! Transmission: probably spread by respiratory droplets; shared clothing, bedding, etc. may be a source – bacteria may enter a break in the skin; not as contagious as we are led to believe. Epidemiology: most cases in India; Brazil is #2; endemic in Texas & Louisiana - armadillos are reservoirs (may be spread by touching/eating armadillos) Culture: never grown in the lab in artificial culture (only in animal reservoirs) Diagnosis: lepromin skin test like tuberculin skin test Treatment: can be cure with antibiotics (same as with tuberculosis) |
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Gas Gangrene - Clostridium perfringens and other species
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aerotolerant anaerobes, endospore formers.
often a mixed infection causes a “snap, crackle, and pop” sound in crepitant tissue (distorted tissue caused by gas bubbles). |
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Necrotizing fasciitis [=Flesh Eating Strep] – Streptococcus pyogenes
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usually Streptococcus pyogenes; less commonly S. aureus
Examples of transmission: abdominal surgery, scratching a rash, giving birth vaginally, little cut on finger, rug burn, broken leg, chicken pox lesions, etc.; bacteria are introduced from a person carrying Strep A Bacteria attack the subcutaneous connective tissue (under the skin) which then becomes gangrenous; infection moves swiftly under the skin where it is unobservable at first. Infected tissue must be removed; if diagnosed early, tissue loss is less severe; in more advanced cases, limb amputation is necessary Bacteria causes body to go into systemic shock so that all systems fail |
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Foot and Mouth Disease (FMD)
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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 fever and blister-like lesions followed by erosion on the tongue, lips, mouth, teats and between the hooves; sticky, foamy, stringy saliva is produced; food consumption is difficult; abortions often occur; milk flow drops; lameness disease often leaves the animals debilitated and causes severe losses in the production of meat and milk spread by animals, people, or materials that bring the virus into physical contact with susceptible animals vaccine is available but only used in emergency situations as animals would then test positive so could not be shipped internationally studies indicate virus can drift up to 40 miles in the wind |
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Molluscum Contagiosum – Molluscum Contagiosum virus
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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 become a sexually transmitted disease in adults. It is believed to be a member of the pox virus family. Transmission: may be sexually transmitted by skin-to-skin contact may be transmitted from fomites such as towels and clothing Symptoms: lesions are usually present on the thighs, buttocks, groin, lower abdomen, external genital and anal region; children typically develop lesions on the face, trunk, legs and arms; lesions may begin as small hard bumps which can develop over a period of several weeks into larger sores/bumps; they can cause itching or tenderness in the area, but in most cases the lesions cause few problems Complications: People with AIDS or others with compromised immune systems may develop extensive outbreaks. Treatment: most symptoms are self-resolving, but generally lesions are removed; lesions can be removed surgically and/or treated with a chemical agent; cryotherapy is an alternative method of removal. |
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Genital Warts – Human Papilloma virus
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all warts are caused by different strains of human papilloma viruses (HPV); researchers have identified > 100 strains of HPV; some strains cause genital warts; plantar warts are caused by a different strains than genital warts
some warts are malignant (cancerous) – some strains associated with cervical cancer; grow on skin, genitals, respiratory tracts, oral cavity most cervical cancer is caused by HPV warts are more common in women genital warts are one of the most common STD's; many people are asymptomatic usually transmitted by direct contact (skin to skin) infection is lifelong; no cure for infected but warts can be removed - treated with cryotherapy (freezing) or caustic chemical agents virus is lysogenic; viral DNA inserts into the host cell’s chromosome and alters the DNA so that the host cell divides out of control Gardasil vaccine (genetically engineered) |
