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Microbiology Final

Dr. Mittak's Microbiology Final

QuestionAnswer
The ______________________ is the most commonly affected system. Respiratory System
The respiratory is divided into ___ parts, what are they and how are they divided? 2, upper and lower; based on structures and functions in each part.
What is included in the upper respiratory tract, how severe are infections? Nasal cavity, sinuses, pharynx and larynx; infections fairly common and nothing more than an irritation
What is included in the lower respiratory system, how severe are infections? Lungs and bronchi; infections are more dangerous and can be difficult to treat.
Lower respiratory tract is essentially a ____________ environment. sterile
How can water be a source of respiratory infections? Legionellosis, contaminated water can be aerosolized, droplets can be inhaled and infections can result
Who will fungi give respiratory infections and which are the most dangerous? Especially for immunocompromised patients. Most dangerous are aspergillus and pneumocytosis
What pathogen is specific for the lung? Legionella
What pathogen can infect multiple sites? Streptococcus: middle ear infections, sinusitis, pneumonia
What are the 4 frequent sites of infection? Middle ear Mastoid cavity Nasal sinuses Nasopharynx
What organ is the most important part of the respiratory tract and what can disable it? Mucociliary escalator; smoking, huffing and other exogenous agents
What can affect the diaphragm giving a common misdiagnosis of acid reflux? Hiatal hernia
What is atypical pneumonia? Walking pneumonia
What are 4 types of upper respiratory tract infections? 1. Otitis media, mastoiditis and sinusitis 2. Pharyngitis 3. Scarlet fever 4. Diphtheria
The middle ear, mastoid cavity and sinuses are connected to the _____________. Nasopharynx
What type of epithelial cells to the sinuses and eustachian tubes have and how does a virus get in? ciliated epithelial cells; virus invades the ciliated epithelium which destroys the ciliated cells allowing bacteria to invade.
Why is mastoiditis dangerous? Its proximity to the CNS and large blood vessels.
A variety of bacteria can cause infection in the _______. What is the classic infection and what are some features? Pharynx; Streptococcus pyogenes, contains M proteins that inhibit phagocytosis. Produces pyogenic toxins which cause symptoms seen with pharyngitis.
Group ___ streptococci can cause abscesses on the tonils. A
__________ can cause scarlet fever and toxic shock syndrome. S. pyogenes
What is scarlet fever caused by and who's affected? Group A streptococci; children under 18 y/o
How do symptoms of scarlet fever begin? How long do they last? Appearance of a rash, tiny bumps on chest and abdomen that can spread all over body and appear redder in armpits and groin. Lasts 2-5 days
What are other symptoms of scarlet fever? Very sore throat with yellow or white papules. Fever of 101F or higher Lymphadenopathy in neck Headache, body aches and nausea
What causes diphtheria? Corynebacterium diphtheriae: a potent inhibitor of protein synthesis
Diphtheria is a ___________ infection and can present how? localized; severe pharyngitis and can be accompanied by plaque-like pseudomembrane in the throat
___________ can make diphtheria life threatening, why? Toxemia; can involve multiple organ systems and can cause acute myocarditis
How is diphtheria transmitted? (3) Droplet aerosol, direct contact with skin, fomites (lesser degree)
What are local effects of diphtheria? Epithelial cell necrosis Inflammation
What is the diphtheria pseudomembrane made up of? fibrin, leukocytes, cell debris; size varies from small and localized to extensive an extensive membrane can cover the trachea
Diphtheria can also be _________ causing acute _________. systemic; myocarditis
How long does diphtheria take to incubate, how does it present and where can the pseudomembrane develop? 2-4 days; pharyngitis or tonsillitis with fever, sore throat and malaise; On tonsils, uvula, soft palate or pharyngeal walls
What is the difference in complicated and uncomplicated cases of diphtheria? Complicated cases are due to respiratory obstruction can result in suffocation. Uncomplicated cases resolve spontaneously.
What is rhinovirus made up of? 50% are picornaviruses: extremely small, non-enveloped, single-stranded RNA viruses
What does rhinovirus mostly cause and when is infection seen? Mild upper respiratory infections, known as the common cold. Seen throughout the year but major outbreaks in spring and early fall.
What is the pathogenesis of rhinovirus? Incubation period is 2-3 days, acute symptoms can last 3-7 days. Infection is usually mild
How many types of parainfluenza are there, what group do they belong to and what do they contain? 4; paramyxovirus group; single-stranded enveloped RNA viruses; Contain H and N spikes but not true influenza.
What are some differences between influenza and parainfluenza? Parainfluenza replicates in the cytoplasm, it is faster, little mutation and not seasonal. Influenza replicates in the nucleus, slower and seasonal.
Parainfluenza is a serious problem for what age groups and why? infants and small children; only transitory immunity to reinfection, infection becomes milder as the child ages.
What is the pathogenesis of Parainfluenza/croup? Onset may be abrupt. progresses over 1-3 days to involve the lower respiratory tract. Illness lasts b/w 4 and 21 days usually 7-10
What does type 1 parainfluenza cause and when do outbreaks usually occur? Major cause of laryngotracheitis (acute croup) in little ones. Severe upper respiratory illness in all age groups. Outbreaks in fall: "back to school croup"
What does type 3 parainfluenza cause and when do outbreaks usually occur? Severe lower respiratory infection in little ones. Bronchitis and pneumonia in children under 1. Infections can occur throughout the year. 50% of all children are exposed in 1st year of life.
What are the 9 bacterial infections of the lower respiratory tract? 1. Bacterial pneumonia 2. Chlamydial pneumonia 3. Mycoplasma pneumonia 4. TB 5. Pertussis 6. Inhalation anthrax 7. Legionella pneumonia 8. Q fever 9. Psittacosis (ornithosis)
What is one of the most serious lower respiratory tract infections? What 2 types are there and what can cause them? Bacterial pneumonia. Community acquired and nosocomial. Variety of organisms
Nosocomial bacterial pneumonia occurs how long after admission? What is it associated with and when is it difficult to deal with? 48 hours after hospital admission. Stapylococcus aureus or gram-neg bacteria. if resistant to antibiotics
How does community acquired pneumonia usually present? What accompanies it? Lobar pneumonia; fever, chest pain and production of purulent sputum.
What is atypical pneumonia? What is its common name? Coughing w/o sputum, caused by variety of bacteria. WALKING PNEUMONIA
The treatment of bacterial pneumonia depends on what 2 factors and what is the most common pathogen? Severity of the infection and type of organism causing the infection Streptococcus pneumoniae
What causes chlamydial pneumonia, when and where is it found, how spread and what can it cause? Chlamydia pneumoniae, throughout the year and world, spread person-to-person, infects the elderly and can cause both community acquired and nosocomial infections.
How does chlamydial pneumonia usually present? Pharyngitis Lower respiratory infection (dry cough) both
What is mycoplasma pneumonia and how does it present? WALKING PNEUMONIA! Initial pharyngitis lasts 1-3 weeks replaced by persistent cough lasting weeks.
What causes mycoplasma pneumonia, how is it acquired, what is ID and where is it found? Mycoplasma pneumoniae, lacks cell wall, acquired by droplet transmission, <100 pathogens, throughout the world especially in temperate climates (above mason dixon line)
What is the incubation period of mycoplasma pneumonia, how is it onset and what areas are affected? b/w 2 and 15 days; insidious onset, fever, HA and malaise for 2-4 days then respiratory symptoms; trachea, bronchi, and bronchioles may extend to alveoli
How long can mycoplasma pneumonia be shed in upper respiratory secretions? 2-8 days before symptoms appear, up to 14 weeks after symptoms subside.
What does mycoplasma pneumonia infection cause? Mild tracheobronchitis, fever, cough, HA and malaise; sometimes sore throat and otitis media (<10 y/o)
How many people are infected with TB, what has had a role in its increase? 1.7 billion people AIDS and HIV (increase efficiency of transmission cycle) poverty and poor socioeconomic conditions are breeding grounds.
What are some initial symptoms for TB? fever, fatigue, weight loss, chest pain, shortness of breath, congestion with coughing.
What causes TB and what are some features? mycobacterium tuberculosis; rod-shaped bacillus, acid-fast staining, non-spore forming, produces mycolic acid (waxy) protects from antibiotics and host defenses
What are the 2 types of TB? Primary: follows initial exposure to the pathogen. Secondary (latent): can occur years later
Primary TB occurs when and what happens once in alveoli? When host encounters pathogen for 1st time. Localized inflammatory response develops, phagocytosis of bacilli by macrophages and PMNs
If pathogens of primary TB are not killed what happens, what sort of response begins and what can form? transported by WBCs to regional lymph nodes and continue to divide intracellularly. Cell mediated immune response begins. If primary lesion not contained, tubercles form (anywhere in body)
What are the tubercles formed by primary TB and what are some features? Aggregates of enlarged macrophages filled with bacteria. Can be surrounded by fibroblasts and lymphocytes, center of tubercle can undergo caseous necrosis that may calcify making readily visible on x-rays.
Most primary TB infections become __________ and __________. quiescent and asymptomatic
About 10% of primary TB evolve into clinical disease, what occurs? Bacilli spread through the lymph channels, bloodstream and GI system and cause TB meningitis, Miliary (disseminated, spreads everywhere except lungs) TB or both. Localized tubercles discharge contents that can distribute to other area of lungs.
What can secondary TB be due to? Reactivation of old lesions, gradual progression of primary TB into chronic disease.
What happens if recurrence of secondary TB occurs? Manifests in apices of the lungs, occurs w/in 2 years of primary infection, can evolve decades later when innate resistance is diminished.
What is prescribed in treatment of TB? Usually a triple therapy including: Isoniazid (INH), Pyrazinamide (PZA), Rifampicin (RFP) all 3 1/day/3 months INH and RFP taken 9 more months. If strain is drug-resistant, tx includes ethambutol.
DOT means what and what is it used for? Directly observed therapy; to prevent multi-drug resistant TB
Directly observed therapy is administered by whom, why and what does it help prevent? By a health care worker who administers, observes and documents that patient received medication; prevents spread of TB and occurrence of multi-drug resistant TB
What is another name for Pertussis, how is it spread and how contagious is it? Whooping cough; airborne droplets from ppl in early stages; highly contagious, infects 80-100% of exposed susceptible individuals, spreads rapidly in schools, hospitals, just about anywhere
What causes pertussis and what are symptoms similar to? Bordetella pertussis a gram-neg coccobacillus, won't survive in environment, human-human disease and reservoir is humans; similar to a cold.
Who has the highest mortality rate with pertussis, when did immunization begin and who is showing infections now? Infants under 1 y/o; 1940s; 10-20 y/o b/c of not being immunized.
What causes pertussis and what cells does it like? Bordetella Pertussis; ciliated bronchial epithelium
What does bordetella pertussis produce after attaching in trachea, where won't it go and what is the incubation time? Tracheal toxin that immobilizes and destroys ciliated cells causing persistent coughing; won't invade cells of respiratory tract or deeper tissues; 7-10 days
How many stages does pertussis have, what are they and in which is it most communicable? 3; Catarrhal, Paroxysmal, Convalescent; Catarrhal.
How long does the Catarrhal stage of pertussis last and what happens with it? 1-2 weeks; persistent runny nose, sneezing, malaise, and anorexia.
How long does the Paroxysmal stage of pertussis last and what happens with it? 2-4 weeks; persistent coughing, classic whooping sound, apnea may follow especially in infants, large increase in lymphocytes.
What occurs in the convalescent stage of pertussis? Frequency and severity of coughing and other symptoms gradually decrease.
What are the most common complications of pertussis? Superinfection with streptococcus pneumonia, convulsions, subconjunctival and cerebral bleeding and anoxia
What does inhalation anthrax produce, how does it come on and what does it lead to? Fulminate pneumonia (90% mortality); suddenly and with great severity, leads to respiratory failure and death
Anthrax is primarily a disease of _________, how is it acquired? herbivores; From spores found in pastures if inhaled can occur in respiratory tract.
Who gets infected with inhalation anthrax and how does it present? Unhealthy individuals; presents as localized lesions where it occurs (black boil disease).
What causes inhalation anthrax, where does it germinate and what does it use for virulence? Bacillus anthracis, gram-positive rod that is spore forming; human tissues; antiphagocytic properties of a capsule aid survival and growth in large numbers.
The pathogenesis of inhalation anthrax is because of what? powerful exotoxin
What are symptoms of pulmonary anthrax and what follows? 1-5 days of non-specific malaise, mild fever, nonproductive cough; progressive respiratory distress and cyanosis, rapid and massive spread to the CNS and bloodstream is followed by death.
What causes Legionella pneumonia? Legionella pneumophila, gram-negative rod that cannot be stained or grown using normal techniques.
Where is legionella plentiful, where does it live and how is it transmitted to humans? fresh water; acathamoeba organisms; as a humidified aerosol never person-person.
Who is affected by legionella and at what percentage? Unhealthy/immunocompromised; less than 5% of population.
What sort of parasite is legionella, what does it attack and what does the exudate contain? Facultative intracellular parasite that attacks the lungs producing a necrotizing multifocal pneumonia; fibrin, PMNs and RBCs
What happens after legionella enters the alveoli? Infect dust cells, produce endocytic vessel that continue replication and prevent fusion of the vesicle with lysosomes.
How does a doctor see legionella is present and how does it look? Bronchial levage; coiled morphology
What does legionella cause and how does it progress? A severe toxic pneumonia; begins w/ myalgia and HA followed by rising fever, chills, chest pain, vomiting and diarrhea, confusion and delirium, infiltrates seen in lung on x-ray can cause hepatic dysfunction.
Serious cases of legionella progress in how many days and how does it end? What is the mortality rate? 3-6 days, shock or respiratory failure; 15% can be as high as 50% in hospital outbreaks
What is Q fever and what is it caused by? A zoonotic infection seen worldwide (ungulates are reservoirs); Coxiella burnetti a gram-neg, spore forming, grows well in animal placentas.
How does transmission of Q fever occur? Can be transmitted by inhalation during animal births and by ingestion of unpasteurized milk.
What is the pathogenesis of Q fever? Begins 9-20 days after inhalation, abrupt onset of chills, fever and HA, can also be a mild hacking cough and some cases show abnormal liver function.
What is Psittacosis and how is it contracted? Zoonotic pneumonia; inhalation of bird droppings infected with chlamydia psittaci some strains extremely contagious
How does Psittacosis present? Acute infection of the lower respiratory tract, acute fever, HA, malaise, myalgia, dry cough and bilateral pneumonia; Systemic complications include myocarditis, endocarditis, and hepatitis (preferential to <3)
75-80% of all acute respiratory infections are _______ in origin. How many do each person have per year and how does incidence vary? Viral; 3-4; inversely with age, greatest in young children.
What causes a majority of acute viral infections in the lower respiratory tract? Influenza virus and Respiratory syncytial virus (RSV)
Influenza virus is an _____________; which means what? orthomyxovirus; virions are surrounded by an envelope
How is the genome of influenza shaped and what are the serotypes? Single-stranded RNA in 8 segments; 3 major serotypes A, B and C. Differences are based on how the antigens are associated with the nucleoprotein.
What can human influenza combine with to produce a highly pathogenic virus? What are the hosts and what are the reservoir? Avian virus; humans host, aquatic birds reservoir
What is the primary manifestation of influenza, since when have outbreaks been described and what is most common method of spread? Severe respiratory problems, since 16th century, occur more frequently in winter; direct droplet transmission.
How often does a major outbreak of influenza occur, how long does it last, how many affected what groups show high illness rates? every 2-3 years; 3-6 weeks; up to 10% affected, exceed 30% in school aged children and residents of closed institutions.
With influenza viral destruction of tissues causes ______ and respriatory epithelium takes how long to be restored? Inflammation; 2-10 weeks
What can result in superinfection by influenza bacteria? Impaired phagocytic and chemotactic responsses.
What is acute influenzal syndrome: incubation time, symptoms? ~2 days, symptoms in a few hours: fever, mayalgia, HA and occasional shaking chills. Maximum severity appears in 6-12 hours non-productive cough develops.
How long can symptoms last in acute influenzal syndrome and is usually followed by? 3-5 days; usually followed by improvement but a progressive infection can develop. This affects the tracheobronchial tree and lungs, lethal pneumonia can occur.
What is a serious complication of influenza, what does it involve and when can it occur? How is it identified? Bacterial superinfection, lungs, convalescent stage; Abrupt worsening of patient's condition after initial stability.
What 3 bacteria are common causes of influenza superinfection? Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus
In what 3 ways can influenza cause death? Underlying disease: people with limited cardiovascular activity or pulmonary infection; Superinfection: Bacterial pneumonia and disseminated bacterial disease; Direct rapid progression: Overwheming viral pneumonia and asphyxia.
What are the 2 approaches to influenza treatment and what is the best? Symptomatic care and anticipation of potential complications; rest and fluid intake, conservative use of analgesics for myalgia and HA, cough suppressants.
When are amantidine and rimantadine useful for influenza treatment? Only if the infection is diagnosed w/in 12-24 hours.
How was Respiratory syncytial virus (RSV) named? Syncytia: cell that is formed through the fusion of multiple cells resulting in a multinucleated mass of cytoplasm
When do community outbreaks of RSV occur, how long do they last and who can it involve? Annually in late fall to early spring; 8-12 weeks; 50% of families with small children
How long is RSV shed, in infants? RSV is a major cause of __________ ________ and control is helped how? 5-7 days and up to 20 days in infants; nosocomial infection: attention to hand washing and exclusion of staff and visitors with respiratory symptoms.
Where does RSV have major pathological consequences and what does it cause? Bronchi, bronchioles and alveoli; Necrosis, interstitial mononuclear cell infiltration and inflammation, can result in the plugging of small airways with mucus, necrotic cells and fibrin.
What is the incubation time of RSV, what are the clinical signs? 2-4 days followed by onset of rhinitis and severity peaks w/in 3 days; hyperexpansion, hypoxia, hypercapnia, pulmonary collapse
How long do acute signs of RSV last, who is the infection mild with and with whom is it fatal and why? 10-14 days; older children and adults; infants, fatality rate is 1% but in compromised children can get up to 15%
What does the Hantavirus cause, what is the most common type and what are infections associated with? A fulminant respiratory infection; Sin Nombre; increases in rodent population.
How is Hantavirus transmitted? Via dried rodent excreta: by inhalation, conjunctival route, direct contact through breaks in skin.
What 2 factors govern the incidence and spread of fungal infection? Ubiquity of the infectious organisms: found in soil, resident flora and The adaptive immune response: usually keeps infections under control, immunocompromised at greater risk.
Pneumocystis pneumonia is common in what population and what is it caused by? AIDS patients; Pneumocystis (carinii) jiroveci: never grown in culture and info. comes from clinical info. from patients.
What are the principal manifestations of Pneumocystis pneumonia infection? Progressive dyspnea, tracheal pneumonia, eventual cyanosis and hypoxia, nonproductive cough in 50% of patients (fungus can't be expressed as liquid)
What do x-rays show in pneumocystis pneumonia and what does it cause? Alveolar infiltrates spreading out from the hila, causes decreased O2 capability, decreased saturation of arterial blood, decreased vital capacity, death occurs through progressive asphyxiation. (Can become systemic with lesions in other areas)
What causes blastomycosis, where can the spores enter, what and who does it affect? blastomyces dermatitidis; respiratory system; lungs but can spread through blood and affect other parts and men b/w 20 and 40
Blastomycosis infection of the lungs is _________. What are other symptoms? gradual; fever, chills and drenching sweats develop, chest pain, difficulty breathing and cough may also develop, can sometimes heal w/o treatment.
When blastomycosis spreads it can affect other areas, what are the findings in the other areas (3)? Skin: warty patches develop surrounded by tine painless abscesses Bones: painful swellings Genitourinary tract: prostatitis or painful swelling of epididymis
What causes Histoplasmosis, where does it occur and where is it commonly found? Histoplasma capsulatum; Soil contaminated with bat or bird droppings; temperate, subtropical and tropical zones.
How does transmission of histoplasmosis occur and what are symptoms? Inhalation of conidia, small enough to reach bronchioles and alveoli and b/c of size referred to as microconidia. Most cases asymptomatic but some present w/ fever and mild cough.
A majority of histoplasmosis cases never go further than ________ formation, what can severe cases develop? tubercle; chills, malaise, chest pain and extensive pulmonary infiltration.
What causes coccidioidomycosis, what is the symptomatic form known as and what is it restricted to? Coccidioides immitis; valley fever; certain geographical areas (generally western U.S.).
Over half of people infected with coccidioidomycosis show no signs of infection, how do those with valley fever present? malaise, cough, chest pain, fever and athralgia; all signs occur 1-3 weeks after infection begins and can last up to 6 weeks.
What percentage of patients infected with coccidioidomycosis experience pulmonary symptoms, disseminated form is seen with whom and what else can it cause? 10%; pt's with AIDS and on immunosuppressive therapy; coccidioidal meningitis
Aspergillosis is typically seen in whom and shows a rapid progression to what? The immunocompromised, leukemia or AIDS, bone marrow transplants and pt's with pulmonary disease; death.
What causes apergillosis, how is it dispersed and where is it seen more frequently? Aspergillus; inhalation of resistant conidia; nosocomial infections associated with AC systems.
Colonization with aspergillus leads to invasion of ________ then what happens? tissues; if in lung tissue can cause penetration of blood vessels which causes hemoptysis and/or acute pneumonia.
Aspergillus pneumonia is accompanied by what, what is the prognosis and the mortality rate? multifocal pulmonary infiltrates and high fever; grave; 100%
Infections in the blood easily become _______ and these infections can do what? systemic; can have devastating effects on the patient
What are the 4 classifications of blood infections? 1. Bacteremia 2. Viremia 3. Fungemia 4. Parasitemia
What 2 syndromes from pathogenic organisms growing in the blood can occur? 1. Sepsis 2. Septic shock
What are intravascular infections and what are they most commonly caused by? When pathogens enter the blood and damage the structures of the cardiovascular system; Bacteria, sometimes fungi.
What are 3 types of intravascular infections? 1. Endocarditis: infection of the heart 2. Thrombophlebitis: infection of the veins 3. Endoarteritis: infection of the arteries
What does infectious endocarditis affect? Heart valves and can also develop on the septa of the heart and cardiac shunts.
With infectious endocarditis, circulating pathogens adhere to the fibrin and platelets, what can occur as a result? (3) Mature vegetation protects the pathogens from host defense, also helps keep out antibiotics. Causes alterations in cardiac endothelium -> obstructs blood flow and increases turbulence. Turbulence can cause parts of vegetation to fall off -> embolus
Transient bacteremia is common after some medical procedures which is usually what and why? Of no clinical importance, organisms involved have low levels of virulence but can colonize the heart valve if endothelium altered.
What organisms are associated with infectious endocarditis? Streptococcus viridians Enterococci Other streptococci Coagulase negative staphylococcus Gram - bacilli (<-result from medical procedure all rest normal flora)
In IV line and catheter bacteremia blood is colonized by organisms normally found where? On the skin. In debilitated hosts bacteremia can persist and increase the chance of endocarditis and distal infections.
What species are commonly involved in IV and catheter bacteremia? S. epidermis, S. aureus, Cornyebacterium
If IV fluid becomes contaminated what is involved? Gram-negative rods such as pseudomonas
What do most bacteremias result from, where do the organisms move from there? An extravascular infection; from infected tissue to lymphatics most are caught here but w/ overwhelming numbers some make it into the blood.
What are the 3 most common sources of bacteremia with extravascular infection? 1. UTIs 2. Respiratory infections 3. Skin infections
Sepsis and septic shock result from what? Progression of bacteremia. Gram-positive and gram-negative bacteria can be responsible, fungi, protozoa and viruses can also be the cause.
What is sepsis? An infection which causes a host response including fever, chills and tachycardia (increased HR).
What are 5 bacterial infections of the blood? 1. Plague 2. Tularemia 3. Brucellosis 4. Lyme disease 5. Relapsing fever
How is plague transmitted to humans, what makes it distinct and how does it spread? Vector transmission, most explosively virulent bacterial infection and spreads from lymph nodes to blood where it can move on to the lungs. AKA pneumonic plague
What bacterium causes the plague? Yersinia pestis
In what 2 forms does plague exist? Sylvatic: seen in wild rodents Urban: seen in cities Urban form more infectious b/c more potential hosts
Bite of the infected flea causes ____________ which is normally not ____________. What form is? Bubonic plague; contagious. Bacteremia can spread to lungs where pneumonic form develops and this is very contagious.
What is the pathogenesis of plague? Bacteria multiply rapidly in lymph nodes, producing a bubo (swelling) and from there bacteria can rapidly spread to the blood.
What is the incubation period of plague and w/o treatment what can patients develop? 2-7 days, fever and painful buboes. 50-75% can develop bacteremia, septic shock causes death but if localized in lungs death occurs in 2-3 days.
What is tularemia? Infection of wild animals that can be transmitted to humans. Infected animals may not show any signs.
What is tularemia caused by? Francisella tularensis that is fastidious and can take up to 10 days to incubate.
Tularemia has a _______ ID50 with what types of routes of infection? small; inhalation, tick bite, ingestion of contaminated meat or water or direct contact with abrasion or cut.
Where can tularemia be found? Throughout the northern hemisphere.
What forms at an infection site with tularemia? Ulcerated lesion, organisms move into organs of the mononuclear phagocytic (likes serosal tissue) system and form granulomas
What occurs with ulceroglandular tularemia? Causes localized papule at inoculation site, becomes ulcerated and necrotic, leads to swelling of regional lymph nodes and very painful.
What is oculoglandular tularemia? Infection acquired through the eyes that produces a painful and purulent conjunctivitis.
What causes typhoidal tylaremia and how does it present? Ingesting a large number of Francisella bacilli, presents with symptoms similar to typhoid fever
What is brucellosis? A zoonotic infection that involves infection of the reproductive tract.
How is brucellosis transmitted and what type of illness does it produce? Occupational contact or ingesting contaminated animal products; chronic illness in humans that can last for weeks or months and causes fever, night sweats and weight loss. Has a cyclic pattern of symptoms (undulant fever).
How does brucella enter the host? cuts in the skin, contact with mucous membranes, inhalation and ingestion.
What are symptoms of brucellosis? Malaise, chills and fever occur for 7-21 days after infection with drenching night sweats; Nocturnal fevers can last for weeks, months or years other symptoms include HA, body aches and weight loss.
What type of tick transmits lyme disease and what causes it? Ixodes tick; spirochete Borrelia burgdorferi which is gram-neg. has similar properties to Treponema pallidum.
B. burgdorferi has at least __ subspecies that are localized how? 10; geographically
Lyme disease is endemic in what areas and what is the primary reservoir for B. burgdorferi? U.S. and Canada and temperate areas of Europe and Asia; Mice
How does B. burgdorferi go through its life cycle? Deer host final stages, fall from deer & lay eggs in soil, eggs hatch and larvae seek out mice for blood meals, bacterium picked up from mice and remains w/ tick, larvae mature and parasitize deer.
How is acute lyme disease characterized? Fever, migratory bull's eye rash, muscular and joint pain, often meningeal irritation
How is chronic lyme disease characterized? Meningoencephalitis, myocarditis, disabling recurrent arthritis
Both acute and chronic forms of lyme disease are highly __________ and lyme is rarely ________. variable; fatal Involve multiple body systems, s/s have overlapping patterns that come and go. If untreated source of chronic ill health.
When the ring of the bull's eye from lyme disease expands it forms what and is accompanied by what? erythema migrans lesion, accompanied by fever, myalgia, HA and joint pain. If untreated skin lesions can disappear while the other symptoms can persist for months.
When does the secondary infection stage begin with lyme disease and what is involved? Days, weeks or months later. CNS involvement can give meningitis, Bell's palsy and peripheral n. destruction. Cardiovascular involvement can lead to myocarditis and heart enlargement.
When can neurologic and cardiovascular symptoms associated with lyme disease resolve? spontaneously in a matter of weeks
How soon can arthritic symptoms arise with lyme disease and what does it mark? Weeks to years after initial onset of the infection. Marks continuing stage of lyme disease.
Arthritic symptoms with lyme disease occur in 2/3 of what patients and what occurs? untreated patients, involves large joints usually the knee and serious cases can cause erosion of bone. Chronic involvement of the CNS can affect memory, mood and sleep.
What causes relapsing fever and how is it transmitted? Borrelia species other than B. burgdorferi. Transmitted by ticks or body lice.
What do the 2 forms of relapsing fever depend on? Whether the vector was a tick or a louse and the type of Borrelia species involved.
What form of relapsing fever is seen in epidemics? Louse-borne
How does relapsing fever present, when do symptoms disappear and relapse? Fever, HA, myalgia and weakness. Disappear in about 1 week and return a few days later.
During relapse of relapsing fever what can be found in patients blood and b/w relapses what occurs? During relapse, spirochetes can be found in patient's blood. B/w relapses circulating organisms disappear and may sequester in the organs.
How many relapses does tick-borne relapsing fever have? 2; fatalities are rare.
How many relapses does louse-borne relapsing fever have? as many as 10; fatalities can reach 40% if untreated, death usually d/t myocarditis, cerebral hemorrhage or liver failure.
What causes rickettsial infections of the blood? Rickettsia are coccobacilli that have charac. of both bacteria and viruses.
What characteristics of bacteria and viruses do rickettsia have? divide by binary fission, very small, gram-neg but stain poorly, are obligate intracellular parasites
What do rickettsial infections of the blood cause and most have what type of reservoir? Cause spotted fevers and typhus-related illnesses, fevers typically accompanied by vasculitis. Most have animal reservoirs transmitted by arthropod vectors, spread through vector's life cycle.
What is epidermic typhus a classic example of? Rickettsial infection, most common in U.S. is RMSF
What characterizes rickettsial infections of the blood? fever, rash and muscle aches. Both types may be fatal as a result of vascular collapse.
What is the ediologic agent in rocky mountain spotted fever? Rickettsia rickettsii
What does rocky mountain spotted fever cause and what are the vectors? acute febrile illness that occurs in association w/ exposure to wooded areas infested w/ ticks. The vectors are ticks but different vectors in different geographic locations.
What is the incubation time for rocky mountain spotted fever what symptoms occur and what is the most characteristic feature? 2-6 days; fever, HA, myalgia and mental confusion. Rash appears on soles, palms, wrists and ankles then moves towards trunk. Rash most charac. feature develops on 3rd day and appearance makes distinguishable from viral infection
What particular muscle can tenderness become extreme in RMSF and what complications can occur if untreated? calf muscles; disseminated vascular collapse, renal and heart failure -> death.
What are the 2 most important types of typhus? Epidemic and endemic
What causes epidemic typhus and how is it transmitted? Rickettsia prowazekii; the human louse
When does rickettsia circulate with epidemic typhus? During acute febrile illness, lice feeds on infected human and becomes infected and then Rickettsia increases
What does a louse do while feeding (epidemic typhus) and how does this get into bite wounds? defecates; rubbed into bite when scratched
How does a rash form with epidemic typhus and what are complications? Begins on trunk and moves into extremities; myocarditis and CNS dysfunction.
What causes endemic typhus, where is the primary infection and how is it transmitted to humans? Rickettsia typhi; rodent to rodent; transmitted by rat flea.
What is the etiologic agent of infectious mononucleosis and Burkitt's lymphoma and what does it have an affinity for? Epstein-Barr virus; B lymphocytes (infection non-productive) and epithelial cells (infection productive)
How is Epstein-Barr virus transmitted and what is it associated with? Repeated contact; salivary glands.
What are the symptoms of infectious mononucleosis? Fever, malaise, pharyngitis, tender lymphadenitis and splenomegaly, persists for days to weeks.
What are complications of Epstein-Barr virus and where is Burkitt's lymphoma common? Laryngeal obstruction (from swelling glands), meningitis, encephalitis, hemolytic anemia, thrombocytopenia and splenic rupture
What are arboviruses and how are they classified? Arthropod borne: carried and transported by insects; fever infections: dengue and yellow fever
How are arboviruses transmitted and what is a feature of arbovirus infection? By mosquitoes; transient viremia
What are the 3 manifestations depending on the arbovirus target and what do all of them produce? CNS, major organs particularly the liver, small blood vessels (capillary networks); produce a cellualr necrosis which instigates inflammation and leads to fever
Why is yellow fever called that, what else can be affected and what is the major complication? First sign is jaundice b/c fever causes necrosis of hepatocytes which can lead to urinary symptoms d/t destroying of renal tubules, brain and heart by destroying myocardium; hemorrhage.
What are clinical symptoms associated with yellow fever? Abrupt onset of fever, chills, HA and hemorrhaging which can become severe causing bradycardia and shock
How does Dengue fever present? Fever, rash, severe pain in back, head, muscles and joints. Severe infections can lead to shock, pleural effusion, hemorrhage and death.
What are the only 2 filoviruses that infect humans? Marburg and Ebola
Ebola is very ___________ and can be transmitted how? contagious; person-to-person with a 90% mortality rate
Where has Marburg virus been seen and what is the mortality rate? nosocomial settings; 25% mortality
What are 5 parasitic infections of the blood? Malaria, toxoplasmosis, schistosomiasis, trypanosomiasis, filariasis
What is Chagas' disease? American form of trypanosomiasis caused by the flagellate protozoan Trypanosoma cruzi.
How is Chagas' disease disseminated, what is the vector and how does it spread? In fecal material of the transmitting vector; reduvid (kissing) bug that feeds on sleeping hosts in evening hours; spread from the site by circulating in host's blood.
Where is Chagas' disease found, how many are affected, amount of deaths each year and leading cause of what infection? Central America to southern Argentina; 16 and 18 million ppl; causes 50K deaths each year, accounts for 25% of all deaths b/w 25-44 y/o; leading cause of heart infection
Why is reduvid called the kissing bug and who/what can be infected? Preferentially bites near lips and eyes; most in children but dogs, cats, rats and opossums can become reservoirs.
In Chagas' disease what accumulates at the bite site and what is the result? Neutrophils, lymphocytes and tissue fluids that results in the formation of a local chancre called a chagoma
What does dissemination of parasite in the host with Chagas' disease cause which can lead to what? Febrile illness; persists for up to 3 months, causes widespread organ damage, any cells can be infected. Heart, skeletal muscle and glial nerve are the most susceptible.
Who shows chronic forms of Chagas' disease and it usually results in what? only in adults; coronary dysfunction
What do filaroidea inhabit and what does this cause? lymphatic systems; acute inflammatory response, chronic lymphatic blockade and swelling of extremities and genitalia = elephantiasis
What 2 parasites are commonly involved in Filariasis and what are they? Wuchereria bancrofti and Brugia malayi; both are threadlike worms that lie coiled up in the lymph vessels for decades.
In filariasis the females of the parasite produce what and what do these do? large numbers of fertile eggs; once laid, embryos uncoil to their full length: microfilariae. The shell of each egg elongates to become a flexible sheath.
In what location do filariasis infections mostly occur and where is the pathology confined? 120 million people infected with either parasite in Africa, Latin America, Pacific Islands and Asia;Humans only known vertebrate hosts, pathology confined to lymphatic system.
What are the 2 types of infection with filariasis? Acute and chronic
The acute form of filariasis is caused by presence of molting adolescent and dying adult worms that stimulate what? Dilatation of the lymphatics, hyperplastic changes to the vessel endothelium, cause infiltration of lymphocytes, plasma cells, and eosinophils -> Forms a granuloma, fibrosis, permanent lymphatic blockade.
What do repeated acute filariasis cause and this leads to what? Massive lymphatic blockade; Skin and subcutaneous tissues fill w/ edematous fluids, bacterial and fungal superinfections can now occur that contribute to further tissue damage
When do chronic forms of filariasis develop and what are major characteristics? 10-15 years after onset of first acute attack, incidence and severity increase w/ age, chronic lymphangitis, thickened lymphatic trunk, chronic lymphadema and elephantiasis.
People with chronic filariasis experience what for how long? Filarial fevers andlymphadenitis for 8-12 months; fevers are usually low-grade and accompanied by chills and myalgia.
Where is lymphadenitis first noted with filariasis? First noted in femoral areas as an enlarged, red, tender lump; inflammation spreads down the lymph. channel of the leg, vessels become enlarged and tender and the overlying skin becomes red and edematous.
What can repeated infections of filariasis cause? Permanent lymphatic obstruction -> edema, ascites, pleural and joint effusion; Persistent lymphadenopathy can cause lymphatic channels to rupture causing formation of abscesses.
Created by: kabrown