Zoonotic Infections

Question 1

Tick vectored pathogens

Answer 1

Erlichia

Borrelia

Rickettsia

Anaplasma

Babesia

Question 2

Bartonella species and the associated infections

Answer 2

bartonella henselae: Cat-scratch fever

Bartonella Quintana: trench fever, bacillary angiomatosis, SBE

Bartonella bacilliformis: bartonellosis/ Oriya fever, verruga

Bartonella Elizabethae: endocarditis

Question 3

Bartonella characteristics

Answer 3

Small gram-negative aerobic bacilli

Intracellular pathogen in blood and RES

Motility is variable based on species

• B. Bacilliformis is only in south america*
• B. Henselae is the most common cat infection*

Question 4

Transmission of bartonella

Answer 4

Bite by arthropod for all except B. Henselae

Bite/scratch by a cat for B hensalae
- causes by flea feeces under the cat claws/ surrounding teeth

highest risks include cat contact, immunocompromised and poor hygiene

Question 5

Bartonellosis due to B. Bacilliformis

Oroya fever

Answer 5

Vector is the sandfly bite

Multiplication occcurs in bloodstream and increases RBC fragility intravascular hemolysis

Oroya fever specifically disables clearance of RBCs

Symptoms:

• fever, malaise, myalgia and headache
• rapidly worsening anemia

Question 6

Bartonellosis due to B. Bacilliformis

Verruga

Answer 6

Worsen of oroya fever

- produces red-purple skin lesions that look like warts and persists for months/years

Question 7

Trench fever 
(B. Quintana)

Answer 7

Vector is body lice

Bacteria survive and multiply in RES cells

Symptoms:

• severe headache
• sudden undulating onset fever (recurrence is 5 days)
• weakness
• rashes
• osteomyalgia in long bones

Question 8

B. Henselae infections (cat-scratch fever

Answer 8

Vector is cat scratch/bite

Bacteria infects RES cells and lymph nodes

Bacterial/septicemia occur in immunocompromised hosts ( really bad)

Is usually benign in children

Symptoms:

• cardinal sign is massively swollen sentinel lymph node to the site of scratch/bite*
• mild fever and malaise
• severe cases causes bacillary angiomatosis

Question 9

Bacillary angiomatosis

Answer 9

Lesions in the skin, liver, lymph nodes and spleen

• most common in immunocompromised patients and is a result of untreated cat scratch fever.

Question 10

Diagnosis of bartonella

Answer 10

• super challenging to culture*

- usually diagnosed via DFA /IFA (assays)

Question 11

Pasteurella multocida

Answer 11

Dog and cate bites are vectors

Gram negative coccobacilli

• oxidase and catalase (+)
• aerobic or facultative aerobe

often presents with cellulitis with onset redness, pain, swelling and low grade fevers

Question 12

Leptospirosis interrogans

Answer 12

Animal urine 
(Specifically in rat and dog owners) 

Spirochete (spiral shaped) bacteria!

Causes two main diseases
-leptospirosis: fever chills, headache, vomiting, rash (mild)
- Weil disease (icterohemorrhagic leptopirosis)
- jaundice, conjunctival injection(blood in eyes)
* causes liver and kidney failure if not treated)
(Major)

Question 13

Tick infection (Ixodes)

Answer 13

Causes three diseases

Lyme disease

Anaplasmosis

Babesiosis

eastern ticks are more infectious than western (idopathically known)

Question 14

Borrelia burgdorferi (Lyme disease)

Answer 14

Spirochete bacteria that causes Lyme disease

3 stages: 3 days- 4 weeks
early localization:
- bullseye rash (erythema migrants)
- flulike symptoms and malaise

Early disseminated: weeks- months

• arthralgia and arthritis
• Bell’s palsy (facial nerve palsy) radicuolpathy

Late chronic: months-years after untreated infection
- chronic skin, nervous system and joint issues

Question 15

Canine sentinel map

Answer 15

Used to determine where human outbreaks are likely since dogs are the most common host of Lyme disease.

• if dog rates go up somewhere, it is likely human rates will as well

Question 16

Relapsing fever

Answer 16

Transmitted by body lice and is from other borrelia species

• incubate for 3-10 days and then produces sudden fever/chills
• fever persists for 3-5 days w/ febrile stages lasting 4-10 days
• followed by another fever and continues this pathogenesis for 3-10 times

Question 17

Anaplasma phagocytophilum

Answer 17

Human granulocyte anaplamosis

• obligate gram-negative intracellular bacteria
• infects leukocytes and erythrocytes and appears like a huge granule (morula)*

Rarely severe of fatal and shows up with flulike symptoms
- sometimes presents in conjunction with limes disease

Question 18

Babesiosis

Answer 18

Babesia Microti is the most common pathogen

presents with Maltese cross or “ring cells”in blood cells (similar to malaria)

Tick is vector and presents with flu like symptoms after 7-10 days

Can also be mistaken with P. Falciparum diseases

Dangerous in elderly and young

Question 19

Erlichia Chaffeensis

Answer 19

Lone star tick is vector

Produces human monocyte erlichiosis

also produces modular and maltease cross, usually in monocytes over granulocytes

Is more severe and fatal than normal ticks
- presents flulike symptoms but fever is out of control if not treated

Question 20

Rickettsia rickettsii

Answer 20

• produces Rocky Mountain spotted fever*
• most serious tick-Bourne disease and is 50% fatality
• rash most common on feet and hands begins 2-4 days after flulike fever and symptoms*
• rash is systemic in organs on top of skin

Vasculitis occurs everywhere and is characterized by lymphocyte-surrounded vasculature
- produces infected cells that swell and necrosis ad well as thrombosis of vessels

Question 21

Difference between R. Prowazekii and R. Typhi

Answer 21

Prowazekii:

• vectored by human lice
• epidemic typhus and 6-30% fatal cases

Typhi:

• vectored by fleas
• endemic typhus but rarely fatal

Both produce rashes that spares palms and soles, unlike rocky mountain

Both produce flulike symptoms and both dont stain well in gram stains
- gram negative and intracellular coccobacilli

Both need giemsa stain in order to visualize easier