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67 terms

Brucellosis - Borrelia recurentis (65)

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Within which immune cells does Brucella spp. multiply?
macrophages
Brucellosis incubation period
1-3 weeks
Describe the onset of Brucellosis.
drenched sweat with high fever in afternoon or evening
Brucellosis clinical presentation
How does brucellosis present in the liver?
hepatomegaly
How does brucellosis present in the limbs?
arthritis
How can brucellosis present in the male genitals?
orchitis

*glandular
Brucellosis Dx
How long does fever in Brucellosis remain after proper treatment?
7 days

*complicates diagnosis
Review serology in Brucellosis
Farmer presents with recurring fever
Brucellosis
Francisiella tularenis gram-staining property and shape
gram-negative coccobacillus
What supplemental compounds are required for growth of Francisiella tularenis on blood agar?
sulfhydryl compounds

*nutritionally fastidious
Francisiella tularenis oxygen requirement
aerobic

*grown on cysteine-glucose blood agar

*slow growth: requires 2-10 days for visible growth
Francisiella tularensis reservoirs
rabbits

squirrels

muskrats

beavers

deer
Francisiella tularensis vectors
ticks

deer flies
What part of the U.S. is the focus of Francisciella tularensis infection?
Southwest to Central U.S.

*map suggests not much of a focus
Fracisiella tularensis transmission (3)
inhalation

ingestion

injection
Describe bacteremic spread of Francisiella tularensis
infects RES with eventual granuloma formation
Francisiella tularensis incubation period
2 to 5 days
Describe acute onset of Francisiella tularensis infection.
fever, chills and malaise
List the 3 types of infection caused by Francisiella tularensis.
Francisiella tularensis Dx
Pasteurella multicoda gram-staining property and shape
gram-negative coccobacillus
Pasteurella multicoda oxidase property
oxidase positive
What type of media is used to grow Pasteurella multicoda?
blood agar

*not on media selective for gram-negatives (MacConkey's)
What is the natural habitat of Pasteurella multicoda?
normal respiratory flora of animals such as cats and dogs

*sometimes found in human sputum
Pasteurella multicoda transmission
bite or scratch by dogs or cats
Pasteurella multicoda Sx
local infection at site of inoculation

diffuse cellulitis with clear border
Pasteurella multicoda Dx
culture from aspirated pus
Causative agent of Glander's disease
Burkholderia mallei
Burkholderia mallei reservoirs
domestic animals --> horses, donkeys, mules

*spread by droplets

*no man-to-man transmission known
Causative agent of Melioidosis (Whitmore's disease)
Burkholderia pseudomallei
What is the natural habitat of free-living Burkholderia pseudomallei?
stagnant fresh water
Burkholderia is endemic in what part of the world?
Southeast Asia
How are animals infected by Burkholderia pseudomallei?
drinking contaminated water
Burkholderia pseudomallei reservoirs
sheep

cattle

pigs

dogs

cats

*man-to-man transmission rare but possible
What are the 4 basic forms of Glanders and Melioidosis?
What form of Glanders and Melioidosis cause the highest fatality rate?
acute septicemia
Glanders and Melioidosis resemble what disorder?
milliary TB
Glanders and Melioidosis Dx
isolate bacteria from blood, sputum, urine, or skin lesions
What 2 disorders are associated with Glanders and Melioidosis?
HIV and diabetes

*Glanders & Melioidosis are complications of HIV and diabetes.
Review zoonotic gram-negative rods.
Yersinia pestis family
Enterobacteriaceae
Yersinia pestis gram-staining property, oxidase, oxygen requirement
gram-negative non-sporeforming rod that is an oxidase negative faculative anaerobe
Name a key virulence factor of Yersinia pestis
rich polysaccharide capsule
Yersinia pestis reservoir
small rodents: voles, rats, ground hogs, rock squirrels
Yersinia pestis vector
Xenopsilla cheopis --> rat flea
Describe the life cycle of Yerisnia pestis.
The rat flea contracts Yersinia when it takes a blood meal from an infected rodent host.

Yersinia multiplies in the GIT of the flea.

The starving flea regurgitates infectious material when attempting to take another blood meal.

Flea eventually dies.
What part of the U.S.A. is endemic for sylvatic plague (Yersinia pestis)?
Four Corners --> Arizona, New Mexico, Colorado, and Utah meet
Yersinia pestis primary exposure
flea bite
Where in the body does Yersinia pestis multiply?
axillary lymph nodes

*higher temperature induces formation of virulence factors

*infected lymph node swells and becomes a bubo (painful swelling of the lymph node)
Yersina pestis secondary exposure
pulmonary infection which can be transmitted via respiratory droplets --> pneumonic plague
Bubonic plague incubation period
4-7 days
Pneumonic plague incubation period
18 to 36 hours
Patient presents with swollen, painful inguinal lymph nodes with increasing fever, pooling of blood and microhemorrhages in the face and extremities.
acute stage of bubonic plague
Patient presents with violent and fulminating bacterial pneumonia.
pneumonic plague
Why are some descendents of survivors of the bubonic plague less susceptible to HIV?
Many persons of European ancestry carry a gene which codes for a defective CCR-5 sequence.
Bubonic plague Dx
Pneumonic plague Dx
Borreliosis reservoir
wild rodent
Borreliosis vectors (2)
louse

tick
How does maintenance of disease differ between the louse-borne and tick-borne borreliosis?
louse-borne: Borrelia recurentis is maintained in human populations

tick-borne: same organism survives in a rodent reservoir
Borrelia spp. gram-staining property and shape
gram-negative spiral (spirochete)
What is the major virulence factor for Borrelia spp.?
outer membrane proteins encoded by plasmids which give organisms increased antigenic variability
Borellia recurentis clinical presentation
Why must blood smears for Borrelia recurentis be taken before the peak of the fever?
At the peak of the fevers, antibodies begin to clear the antigen. This will reduce the probability of actually seeing the antigens in a blood smear.