Zoonotic Infections Flashcards
what is a zoonotic disease
a disease in which initial acquisition comes from an animal, either directly, indirectly (contaminated food, water, unpasteurized milk), or via a vector
brucella sp - physiology and structure
*gram negative coccobacilli
*facultative intracellular
*aerobe
*requires chocolate agar with CO2 for culture
brucella sp - virulence
*facultative intracellular (survives in macrophages)
*inhibits myeloperoxidase-peroxide system
*spread through LYMPHATICS
brucella sp - pathophysiology
*usually ingested (unpasteurized milk or soft cheese) but can be direct inoculation
*host response is GRANULOMATOUS
Brucella melitensis - animal host
goats
Brucella abortus - animal host
cows
Brucella suis - animal host
pigs
Brucella canis - animal host
dogs
where does brucella infection have the highest incidence
Mongolia & Turkey
(middle east, north africa, mediterranean)
brucellosis - clinical presentation
fever
malaise/fatigue
headaches
HEPATOSPLENOMEGALY
lymphadenopathy
brucella - control measures
*pasteurize milk and cheese
*vaccinate food-producing animals
tularemia - agent
Franciscella tularensis
*gram negative coccobacillus
*aerobic
*facultative intracellular
*highly virulent
tularemia - reservoir and vectors
*reservoir = mammalian animals
*vectors = rabbits, ticks, deer flies
tularemia - transmission
inhalation, ingestion, or other contact with infected animals (ex. slaughtering a rabbit)
tularemia - clinical features
*ulceroglandular tularemia: fever, chills, ulcerated skin lesion, painful regional lymphadenopathy
*can lead to really severe septic shock (low BP, organ dysfunction)
tularemia - control measures
*education of hunters (wear gloves and wash hands)
*avoid reservoirs and vectors of infection
*there is a vaccine but rarely used
Q fever - agent
*Coxiella brunettia (a proteobacteria)
*strict obligate intracellular pathogen
*short pleomorphic rod
*survives in macrophages (thus primary site of infection)
*disseminates through LYMPHATICS
Q fever (C. brunetti) - virulence factors
- phase I antigen (cellular entry and attachment; highly infectious)
- phase II antigen (more virulent, but not infectious)
Q fever - epidemiology
*acquired form ungulate (hoofed) animals [cattle, sheep, goats, etc]
*often acquired during assisting with birthing or placenta contact
*AEROSOL transmission
*more prevalence in Europe (France)
Q fever - clinical presentation
*flu-like s/s with fever, headache, malaise
*can cause PNEUMONIA and HEPATITIS
Q fever - diagnosis
serology: antibodies against both phase I and phase II antigens
plague - agent
*yersinia pestis
*gram negative coccobacillus
*SAFETY PIN STAINING
plague (yersinia pestis) - virulence factors
type III secretion system (T3SS): facilitates uptake and survival in the macrophage
plague - reservoir & transmission
*reservoir = mammals & rodents or their fleas
*transmission = direct contact with infected animals (PRAIRIE DOGS, squirrels, cats) or airborne from infected person
plague - clinical syndromes
*short incubation period (1-7 days)
*syndromes: bubonic, septicemic, pneumonic, etc
plague - symptoms
-sudden onset of fever, shortness of breath, hemoptysis, chest pain
-GI symptoms common
-high mortality
plague - control
*rodent and flea control
*antibiotic prophylaxis of contacts or infected individuals or exposures
anthrax - agent
*Bacillus anthracis
*gram positive, spore-forming bacillus
what is the major concern with anthrax
use as a bioterrorism agent
anthrax (Bacillus anthracis) - reservoir & transmission
*reservoir = herbivores (cattle, goats, sheep); capable of surviving in environment for long periods of time
*transmission = contact, ingestion, or inhalation
*contaminated HIDES are common source of infection
anthrax - 3 clinical presentations
- cutaneous (spore in skin; causes ulcer)
- intestinal
- pulmonary (severe; inhalation; into macrophages and spread through lymphatics)
anthrax - virulence factors
1) edema toxin (ATP -> cAMP -> leaky capillaries -> edema)
2) lethal toxin (inflammation & cell death)
*protective factor helps protect these toxins from degradation by human proteases
what disease is associated with MEDIASTINAL WIDENING in a patient in septic shock
ANTHRAX (pulmonary/inhalational anthrax)
anthrax - treatment and prophylaxis
ciprofloxacin is recommended
cat scratch fever - agent
*Bartonella henselae
*probably the most common zoonotic infection in the US
cat scratch fever - clinical presentation
*fever with papule at inoculation site
*regional adenopathy
*comes from bite, lick, or scratch of a cat (usually outdoor kittens)
pasteurella multocida
*facultative anaerobic gram negative coccobacilli
*commensals in oropharynx of dogs and cats (bite = think ab this)
pasteurella multocida - virulence factors
capsule and endotoxin
pasteurella multocida - common risk factors
iron storage disease or liver disease
pasteurella multocida - 3 types of infections
- animal bite
- pneumonia
- systemic infection with septic shock
rabies - agent
*Lyssavirus (a rhabdovirus)
*bullet shaped
rabies - transmission
saliva of infected mammal, usually a bite
rabies - most frequent source in india
dog bite
rabies - most frequent source in US
bats
rabies - pathophysiology
inoculation at site of bite and reaches CNS through retrograde trafficking of virus through peripheral nerve
