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.

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