Zoonotic and Vector-borne Bacterial Infections II Flashcards
Borrelia: Gram stain Shape Aerobic ability Diseases caused (2)
- Neither gram positive nor negative
- Long Spirochete
- Microaerophilic
- Causes Lyme disease and Relapsing Fever
What species of borrelia causes Lyme Disease in U.S.?
Borrelia burgdoferi
What is major vector for Lyme Disease?
Lxodes spp. of ticks
Stages of Lyme Disease (3)
Early stage 1 develops rapidly- localized infection
Stage 2- Disseminated infection
Chronic stage 3 develops 2-3 years after primary infection (persistent infection)
Early infection, stage 1 of Lyme disease:
Lesion
Symptoms (6)
Bulls-eye rash
Malaise, fever, HA, fatigue, myalgia, and lymphadenopathy
Stage 2 Lyme Disease symptoms and timing
- Begins 3-5 weeks after bite
2. Arthralgia, myalgia, cardiac dysfunction, CNS symptoms, meningitis, and encephalitis
Late, Stage 3 Lyme Disease
Symptoms
- One or more joints affected with arthritis
- Skin discoloration and swelling
- Neurological complaints
Lyme disease diagnosis
Diagnosis is based on symptoms, physical findings, and history.
Serology and culture are of limited use
Lyme disease treatment (DAC)
- Early stages
- Late Stage
- Early: doxycycline, amoxicillin, or cefuroxime
2. Late: doxycycline, amoxicillin, or ceftriaxone
Relapsing Fever:
Gram stain
Shape
Types (2) and cause of that type
- Poor staining, gram negative
- Spirochetes
- Epidemic Type (louse borne)
Endemic Type (tick borne)
How does relapsing fever evade the immune system?
Antigenic variation
Epidemiology:
Endemic relapsing fever
Epidemic relapsing fever
Endemic is tick borne, zoonotic, and prevalent in Africa
Epidemic is NOT zoonotic and is transmitted from human to human via louse. Restricted to North Africa and South America
Relapsing fever clinical progression and presentation
Presents as flu-like, possibly with splenomegaly and hepatomegaly.
Symptoms last 3-7 days, resolve, and return after 7 days due to antigenic variation
Relapsing Fever diagnosis and treatment
Diagnosis: microscopy, culture, and/or serology
Treatment: tetracycline or erythromycin
Rickettsia:
Gram stain
Shape
Cellular location
Very small gram negative coccobacilli (difficult to stain)
Obligate intracellular pathogens
Rickettisa manifestations
Skin
Systemic
Skin- inflammation, thrombosis, rash, petechial lesion
Systemic- vascular lesions throughout the body
Rocky Mountain Spotted Fever
Causative agent
Vectored by (2)
Rickettsia rickettsii
Dog tick (east of rocky mountains and pacific coast)
Rocky Mountain Wood Tick (rockies)
When do most cases of RMSF occur?
Where do most cases of RMSF occur?
> 90% of cases reported between April and September
>50% in South Atlantic
RMSF presentation:
Initially presents with fever then 2-5 days later, rash shows up and it is ready to party
Untreated RMSF symptoms (6)
DIC, thrombocytopenia, pulmonary edema, renal failure, GI hemorrhage, and shock
So hell basically…an actual real hell
RMSF Diagnosis (2)
Clinical presentation and hx
Serology
RMSF treatment
Doxycycline is the drug of choice…boom…micro’ed
Ehrlichiosis
Gram stain
Shape
Cellular location
Small, gram negative intracellular pathogens that parasitize monocytes and granulocytes
Ehrlichiosis:
Replicate and form colonies within vacuoles known as…
MORULAE
Types of Ehrlichiosis (2)
Human monocytic ehrlichiosis (HME)
Human gradulocytic ehrlichiosis (HGE)
Principle vectors of HME and HGE
HME: Lone Star Tick
HGE: Lxodes ticks
How do 60% of ehrlichiosis infections present?
How do the other 40% present?
- Asymptomatic or non-specific viral illness
2. Severe enough to require hospitalization
Ehrlichiosis: diagnosis and treatment
Serology and molecular techniques
Treat with doxycycline
Query fever is caused by?
Coxiella burnetii
Q Fever: gram stain shape forms cellular location
gram negative
small and pleomorphic
small and large-cell variants
Intracellular bacteria…they be all up in macrophages and monocytes
What do the small cell variants mimic?
Spores. They can resist high temps, osmotic pressure, UV light, and can survive in environment for months
Which animals are reservoirs for Human Q Fever?
Farm animals, dogs, and cats and primary reservoirs for human disease
How do humans become infected with Q fever?
Contact with placenta or amniotic fluid of infected farm animals, dogs, or cats. Unpasteurized milk and cheese are also sources of infection
Types of infection of Q fever (2)?
Acute and chronic…look at slides for symptoms
Q fever diagnosis, treatment, and prevention
Diagnosis: molecular and serological techniques
Treatment: doxycycline
Prevention: inactivated, whole, cell vaccine to high risk individuals
Bartonella:
Gram stain
Shape
Human pathogens/diseases (2)
Small, curved, gram negative rods
Bartonella quintana- Trench Fever
Bartonella henselae- Cat Scratch Fever
Trench Fever:
Transmitted by?
Associated with?
Presentation
Transmitted by human body louse through their feces
Associated with poverty, lack of hygiene, and overcrowding
Presents with relapsing fever which recurs every 4-6 days
Diagnosis and treatment of Trench Fever?
Diagnosis: serology is best option
Treatment: gentamicin or erythromycin
Cat scratch fever:
Transmitted by?
Ok..this is a bit weird
Patient gets bitten or scratched by a cat and flea feces from fleas on cat get into the bite
Cat scratch fever diagnosis and treatment
Culture, serology, or molecular analysis
Treatment is not usually needed. Antibiotic use is questions but if needed, azithromycin is recommended
