Zoonoses -Bac Inf 1 Flashcards
Zoonotic Diseases definition
diseases spread to man through contact with animals or which have animal reservoirs.
anthrax -organism, vector, reservoir?
- bacillus anthracis
- no vector
- cattle sheep goats
brucellosis-organism, vector, reservoir?
- brucella abortus; B melitensis; B suis
- no vector
- cattle sheep goats
pasteurellosis- organism, vector, reservoir?
- pasteurella multocida
- no vector
- cats dogs
melioidosis- organism, vector, reservoir?
- burkholderia pseudomallei
- no vector
- probably has reservoir but dont know which animal
leptospirosis- organism, vector, reservoir?
- leptospira interrogans
- no vector
- rodents, small mammals
tularemia- organism, vector, reservoir?
- francisella tularensis
- vectors: ticks, deerflies
- rabbits, hares
plague- organism, vector, reservoir?
- yersinia pestis
- vector: fleas
- rodents, prarie dogs
lyme disease- organism, vector, reservoir?
- borrelia burgdorferi
- vector: ticks
- mice, deer
relapsing fever-organism, vector, reservoir?
- borrelia recurrentis
- lice
- no reservoir animal
Bacillus anthracis - causes and organism info
- anthrax durp
- large, aerobic, spore forming, gram positive rod, long chains, pairs or as single cells
- Gram-stained organisms (from culture media) have squared ends, = “boxcar” appearance
- spores can be observed in culture and in soil, and can remain viable for decades: not generally observed in clinical samples
- non-motile
- grow quite readily on conventional laboratory culture media (blood agar plates)
Bacillus anthracis - pathogeneisis
- protein capsule: poly-D-glutamic acid; not produced in culture; antiphagocytic (NOT PEPTIDOGLYCAN)
- toxin (s): three protein subunits which combine to form two different toxins ; responsible for much of the pathology associated with disease
Anthrax toxins:
- Lethal factor (LF)
- Protective antigen (PA)
- edema factor (EF)
- lethal toxin = Lethal factor + Protective antigen===> tissue damage and shock
- edema toxin = Protective antigen + Edema factor===> edema
Bacillus anthracis - how do you get infected?
- spores can be inoculation, ingestion, or inhalation
- contact with infected animals or animal products
- spores may be present in contaminated soil, or animal furs, hides, wool or skin
Bacillus anthracis - disease process
- spores germinate, producing vegetative cells which produce toxin
- PA binds to cellular receptors on numerous tissues and cell types
- PA is cleaved by cellular enzymes to an active form and forms a multimeric complex on the cell surface
- LF and / or EF bind to this complex and are internalized by the cell
- LF disrupts normal cellular signaling events leading to cell death, inflammation, and tissue damage.
What is edema factor?
- Bacillus anthracis toxin
- adenylate cyclase that increases intracellular cAMP levels, disrupting cellular ion/H2O transport, thereby causing edema.
Bacillus anthracis - vectors?
cattle, sheep, goats, horses –> animals become infected while grazing in contaminated pastures
Bacillus anthracis - most commonly aqcuired…
- most human cases acquired through the inoculation of spores: direct inoculation or contamination of existing open wounds
- inhalation is the principal route of transmission favored for the use of anthrax as a biological weapon
Bacillus anthracis - rare to acquire via…
infection by ingestion of contaminated meat is a rare route of acquisition
Bacillus anthracis - inoculation with spores=
cutaneous anthrax
Bacillus anthracis - ingestion of spores =
gastrointestinal anthrax
Bacillus anthracis - inhalation of spores =
inhalation anthrax
Cutaneous Anthrax - presentation:
- Small red papule, then vesicle, then necrotic ulcer (eschar) with black center
- Described as painless
- May be accompanied by lymph node swelling
- Lesions may resolve over a period of several weeks
- MOST CASES HERE
Gastrointestinal Anthrax - presentation:
- Upper GI involvement includes oropharyngeal ulcerations (tongue, tonsils, esophageus) with cervical adenopathy and fever
- Intestinal involvement includes abdominal pain, nausea, fever, bloody vomit, bloody diarrhea
- May progress to sepsis
- Case-fatality rates as high as 100 %
Inhalation Anthrax
- Initially presents as non-productive cough, shortness or breath, myalgia, fatigue, and fever
- Followed by increasing fever, drenching sweats, extreme dyspnea, cyanosis, lymphadenopathy, shock, and in most cases death.
- Mortality rate is 45 to 75% even with treatment
Anthrax Diagnosis
- Clinical signs
- History of exposure
- Gram-stain of clinical samples (wound exudate, lymph node material, pleural fluid, blood)
- Large numbers of organisms typically present
- Culture
Anthrax - treatment/prevention
- antibiotic treatment: Penicillin & Ciprofloxacin (start cipro until youre sure its not a penicillin resistant strain)
- vaccination: Effective in animals; Limited use in humans (military, lab workers, veterinarians)
- dispose of infected animals
Brucella sp - disease name and orgnaism details:
- brucellosis
- small, slow-growing, aerobic, gram-negative coccobacillus.
- difficult to grow in culture–require specialized media –> INTRACELLULAR PATHOGEN (inside monocytes and macrophages)
- organism is hidden from humoral ijmmune system
- spreads throughout bod via monoytes/macrophages
B. abortus vector?
cattle
B. melitensis vector?
goats and sheep
B. suis vector?
pigs
CMI (IFN-gamma) essential to resolution of which disease?
Brucellosis – Brucella sp. - these suckers live inside monocytes and macrophages— need inf gamma to piss off the macrophages to activate them
Brucella sp. -brucella abortus; B melitensis; B suis- endotoxin
the composition of the O-antigen (polysaccharides) of Brucella LPS can vary greatly, and appears to affect virulence.
Brucella sp - brucella abortus; B melitensis; B suis.- human infection how?
-initiated through direct contact with animal secretions
-through the conjunctiva or small skin lesions
consumption of contaminated foods – unpasteurized milk / dairy
-inhalation of infectious aerosols
-typically an occupational disease in slaughter house workers, butchers, veterinarians, farmers and ranchers
Brucella sp - brucella abortus; B melitensis; B suis- where in the world most common?
Mediterranean, Latin America, Middle East
ESP UNPASTURIZED DAIRY PRODUCTS
Brucella sp.- brucella abortus; B melitensis; B suis- disease progression
- Initially non-specific symptoms
- Fever, chills, night sweats, myalgia, arthralgia, cough
- Fever may be intermittent – “undulant fever”
- Advanced disease
- GI symptoms (nausea, vomiting, diarrhea)
- Bone and joint infections
Brucella sp - brucella abortus; B melitensis; B suis - dianosis
- Culture blood, bone-marrow, and organ biopsy samples
- Growth may take several days or several weeks to appear
- Serological and molecular techniques
Brucella sp - brucella abortus; B melitensis; B suis- treatment/prevention
-Treatment: Doxycycline
-Prevention:
limit occupational exposure
pasteurization of dairy products
vaccination of animals
Pasteurella multocida causes waht disease and organism details
-Pasteurellosis
-gram-negative, facultatively anaerobic coccobacilli
-related to the genus Haemophilus
-commensals or normal flora in the nasopharynx of many animals (including dogs and cats)
grows well on the both blood and chocolate agar
-possess LPS and is encapsulated
most common agent of human disease?
p multocida
Pasteurella multocida - human infection?
bite/scratch of cat or dog
Pasteurella multocida - disease progression
- wound begins to redden and swell
- becomes painful
- cellulitis and abscess formation may occur
- may be accompanied lymphadenopathy
- possible spread to tendons, joints, and bones if untreated
Pasteurella multocida - diagnosis/treatment
-Diagnosis: clinical signs history of exposure cultivation and biochemical testing -Treatment: Penicillin
Burkholderia pseudomallei - causes waht disease and organism details
-meliodosis
-motile, gram-negative rod –> has LPS
(related to Pseudomonas )
-normally found as a saprophyte in surface waters and soil
-polysaccharide capsule
-lethal toxin and degradative enzymes
-type III secretion system
-intracellular pathogen(?)
Burkholderia pseudomallei - msot common where in the world?
southeast asia and australia
Burkholderia pseudomallei - human infection
- small wounds or abrasions are contaminated with soil or water containing the organisms
- zoonotic nature of infection has been brought into question due to the lack of evidence supporting direct transmission from animals to humans
- need to be in regular contact with soil and water
Burkholderia pseudomallei - disease progression
-most exposed individuals are thought to remain asymptomatic
-may develop following several days incubation, or may remain latent for months / years
-initial cutaneous disease =single or multiple tender nodules or abscess accompanied by lymphadenopathy, fever and malaise
may resolve spontaneously or the infection may become systemic
-pulmonary disease may vary in severity from bronchitis to necrotizing pneumonia accompanied with high fever, dyspnea, and cough with sputum.
Burkholderia pseudomallei - diagnosis/treatment/prevention
- Laboratory identification is dangerous - call someone who knows what theyre doing
- Clinical signs, history of travel to endemic areas
- Treatment and Prevention: long term treatment with high doses of antibiotics
Leptospira interrogans - causes waht disease and organism details
- leptospirosis
- thin, motile, gram-negative, spiral shaped bacteria with terminal “hooks”
- grow slowly in culture with optimal growth occurring between 28O-30O C.
- poorly staining, require specialized techniques of microscopy to view (dark-field microscopy)
Leptospira interrogans - disease progression
- can invade abraded skin as well as intact mucus membranes - contact with water that has animal urine
- enter the bloodstream and disseminate
- mechanism of bacterial virulence are poorly understood
- most infections thought to present as self-limited, nonspecific febrile illnesses
Leptospira interrogans - is found where in the world most often?
hawaiian isalnds - exposure to water with animal urine!
Leptospira interrogans - human infection
- develops following the aquisition of bacteria from water contaminated by animal urine
- most infections result from recreational (swimmers) or occupational exposure (veterinarians)
Leptospira interrogans - first stage of disease progression
- febrile influenza-like illness
- organism may be detected in blood, urine, and CSF
- symptoms last for ~1 week
- followed by resolution or progression to second phase
Leptospira interrogans - secondstage of disease progression
- patient may present with meningitis, inflammation of the eye, jaundice, renal failure, and petechial rash
- may progressive to respiratory, hepatic, and / or circulatory failure
- mortality of 5 to 40% have been reported
Leptospira interrogans - diagnosis/treatment/prevention
-Diagnosis
thorough history including occupational and recreational activities and potential animal contacts
cultivation and biochemical testing is difficult
serology is generally employed to confirm infection
-Treatment: Penicillin and Ampicillin
-Prevention: Limiting exposure to animal urine
Francisella tularensis- causes waht disease and organism details
- tularemia
- is a small, slow-growing, aerobic, Gram-negative coccobacillus
- difficult to grown in culture.–> intracellular pathogen of monocytes and macrophages
- intracellular pathogen
- ->prevents phagosome-lysosome fusion and acidification
- -> CMI: macrophage activation is crucial to the resolution of infection
- Encapsulated
- ->pathogenicity is strongly associated with capsule production: antiphagocytic properties; protects the bacteria from lysis by the complement system
- possess LPS
Francisella tularensis-human infection
- Acquired through contact with infected blood or tissue
- Inhalation of infected blood aerosol (skinning of animals)
- Ingestion of contaminated meat
Francisella tularensis- disease progression
- initial symptoms of fever, chills, headache arthralgias, and lassitude
- Ulceroglandular tularemia
- Oculoglandular tularemia
- Pneumonic tularemia
Francisella tularensis-is found where in the world most often? time of year? reservoir?
- Primarily a disease of the Northern Hemisphere
- United States: Oklahoma, Missouri, Arkansas
- Summer infection=tick season
- Fall / Winter=small game season
- hares and rabbits
Francisella tularensis-vector?
hard shelled ticks - less likely for humans to get this way… usually need to be directly in contact with animal - skinning rabbits… etc
Francisella tularensis-Diagnosis
- History or exposure and clinical suspicion
- Serology and molecular techniques
- Cultivation is slow and difficult
Francisella tularensis-treatment/prevention
-Treatment: Gentamicin
-Prevention:
prevent tick bites
hunter education
take precautions when skinning animals
Ulceroglandular tularemia
- caused by Francisella tularensis
- Develops following direct inoculation or tick bite
- red, painful swollen papule
- becomes purulent and ulcerates
- regional lymph nodes swelling
- Lymph nodes may suppurate (fill with pus) and may even ulcerate.
- Patient may become bacteremic
Oculoglandular tularemia
-caused by Francisella tularensis
-Develops following ocular inoculation
painful conjunctivitis with swollen cervical lymph nodes develops
Pneumonic tularemia
- caused by Francisella tularensis
- develops following the inhalation of an infectious aerosol
- pneumonitis (lung inflammation) and eventually sepsis
- high rate of morbidity and mortality unless promptly recognized and treated
Yersinia pestis- causes what disease and organism details?
- plague (same frmo back in the days = black death in europe)
- a non-motile, gram-negative rod (Enterobacteriaceae)
- proteinaceous capsule
- grows well on most conventional laboratory media
- histological stains (Giemsa) reveal a rod shaped organism with a characteristic bipolar staining, giving the appearance of a “closed safety pin”
Yersinia pestis- pathogenesis
- Capsule
- LPS
- Three plasmids associated with virulence
1) encode proteins which facilitate the regurgitation of bacteria by fleas
2) enhance bacterial survival in macrophages
3) allow the organism to resist complement mediated lysis
Yersinia pestis- most common part of the world?
Africa
-more cases reported now in: New Mexico, Arizona, California, Colorado, Nevada, and Wyoming
Yersinia pestis- transmission
-the natural cycle of disease is in rodent and fleas
-human infection is accidental / incidental
the bite of infected fleas
-bites and scratches of cats that have killed infected rodents
-inhalation of aerosol during the skinning and cleaning of infected rodents
-human to human transmission (pneumonic plague) is possible
Bubonic plague - presentation
- Yersinia pestis
- initial symptoms of fever, chills, headache, myalgias
- painful lymphadenopathy develops proximal to the portal of entry – “buboes”
- surrounding area become swollen and inflamed
- overlying skin may become stretched and desquamate.
- if untreated, buboes may perforate leading to bacteremia and septic shock
- 50% mortality
Pneumonic plague -presentation
- Yersinia pestis
- inhalation of respiratory droplets from a person or animal
- may develop in individuals secondary to bubonic plague
- primary pneumonic plaque
- initial signs include fever, headache, myalgias, and respiratory signs (cough, sputum production, chest pains, labored breathing)
- progresses rapidly (2-3 days) to symptoms of hemoptysis, increasing respiratory distress, cardiopulmonary insufficiency, cyanosis, and circulatory collapse
- secondary pneumonic plague develops somewhat more slowly
- bacteria can be readily observed in sputum samples
- 100% mortality
Yersinia pestis- diagnosis/treatment
-Diagnosis: Call the CDC ! Typically requires the intervention of state or federal labs due to infectivity -travel history! Symptoms and exposure history -Treatment: Streptomycin
“closed safety pin appearnace?
Yersinia pestis- plague
Borrelia burgdorferi - causes what disease and organism details
- Lyme Disease
- gram neg spirochete
- microaetophilic
- difficult to culture
Borrelia burgdorferi- Major reservoir, vectors and peak months?
- white-footed mouse and white-tailed deer
- TICK VECTOR
- early stage seen msot often in summer motnhs
Borrelia burgdorferi- disease progression
-Early stage 1 (localized infection) – one or more skin lesions at the site of bite
Lesion starts as small macule or papule, then enlarges (bull’s eye rash; erythema migrans)
-Early stage 2 (disseminated infection) – ~3-5 weeks after the tick bite, the bacteria disseminate via the bloodstream
Systemic symptoms – including arthralgia, myalgia, cardiac dysfunction and neurologic signs
-Late infection, stage 3 (persistent infection) – develops months to years after the initial infection –> Arthritis (one or more joints with knee most often affected), skin discoloration and swelling, neurologic complaints (numbness, memory loss)
Borrelia burgdorferi- diagnosis
- Symptoms, physical findings and history of exposure
- Serology of limited use in endemic areas
Borrelia burgdorferi- treatment/prevention
- For early symptoms – doxycycline, amoxicillin or cefuroxime
- For lyme arthritis – ceftriaxone, doxycycline or amoxicillin
- Prevention by limiting exposure to ticks
Leading vector-borne disease in the US ? second most?
Borrelia burgdorferi- - lyme disease
rocky mountain fever
major vector in northeast and midwest for lyme disease
Ixodes scapularis
major vector on west coast for lyme disease
Ixodes pacificus
bulls eye rash - organism is?
borrelia burgdorferi- lyme disease - bitten by an infected tick!
bluish-red skin lesions associated with
late, disseminated lyme disease - borellia burgdorferi
Borrelia recurrentis- causes what? organism info?
-relapsing fever
-poorly staining gram-negative spirochetes
difficult to grow in culture
-Borrelia recurrentis is the agent responsible for louse borne (epidemic) relapsing fever
-many other species can cause tick borne (endemic) relapsing fever
Borrelia recurrentis- how to get infection? pathogenesis?
- acquired through the bite of an arthropod vector
- enters the circulation and disseminates to multiple organs
- evades immunological defenses through antigenic variation: single bacterium can express ~ 3 dozen unique variable major proteins on its surface; humoral immune system always trying to catch up
- results in a succession of febrile and afebrile cycles (relapsing fever)
- probably a response to the changing amount of organisms( and LPS) in the blood stream
Borrelia recurrentis- disease presentation
- symptoms of chills, fever, headache, muscle aches
- splenomegaly and hepatomegaly may develop
- symptoms last from 3 to 7 days, then resolve and return after another week
- several episodes of relapse may occur before resolution
- mortality rates of 5 to 40% have been reported
Borrelia recurrentis- Diagnosis
- organism may be observed in Giemsa stained blood smear
- cultivation requires specialized media
- serological and molecular techniques are frequently used to confirm diagnosis
Borrelia recurrentis- treatment & prevention
- treated is with tetracycline or erythromycin.
- Prevent disease by limiting exposure to the arthropod vectors
epidemic relapsing fever caused by? vecotr? reservoir? where is this prevalent
- Borrelia recurrentis - BODY LOUSE VECTOR - HUMAN RESERVOIR AND HUMAN TO HUMAN TRANSFER (NOT A ZOONOTIC DISEASE)
- issue in north africa
Endemic relapsing fever - caused by? vector? reservoir? where is this prevalent?
many other species of borellia sp. - SOFT SHELLED TICK VECOTR - rodent, and soft shell tick reservoir
-worldwide issue
endemic = always maintained at low level in geographical area
box car appearance
bacillus anthracis
scratched by a cat or bitten by some animal - organism is?
pasterurella multocida or highly uncommon but possible yersenia pestis
contact with water - potential organisms?
leptospira interrogans and Burkholderia pseudomallei
spiral shaped bacteria with terminal hooks - organism?
leptospira interrogans
antigenic variance to avoid immune detection?
borellia recurrentis!
