Lec17 Vector Borne and Zoonotic Infections Flashcards
What disease does rickettsia spp cause?
- spotted fevers and various types of typhus
What disease does ehrlichia chaffeenis cause?
human monocytic ehrlichiosis [HME]
What disease does anaplama phagocytophilum cause?
anaplasmosis aka human granulocytic ehrlichiosis
What bacteria causes lyme disease?
borrelia burgdorferi
What bacteria causes cat scratch disease?
bartonella spp
Francisella tularensis-Tularemia Leptsopira spp- Leptsopirosis Yersinia pestis-Plague Coxiella burnetii- Q Fever Brucella spp- Brucellosis
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What is the vector for b. burgdorferi?
tick [ixodes scapularis]
What is the life cycle for b. burgdorferi?
- vector is ixodes ticks
- main reservoir in white footed mice
- deer are important for adult stage
- nymphs are responsible for most of the disease
What are early signs of lyme disease?
at first its localized [3-30 days] at site of bite
- have bulls eye rash = erythema migrans
- mild systemic symptoms
What are signs of early disseminated lyme disease?
1-4 months after bite
- cranial nerve [bell’s] palsy
- lymphocytic meningitis
- heart block, myocarditis
- disseminated rash
What are signs of late lyme disease
- intermittent arthritis
- chronic neuro problems [radicular pain, paresthesias, lyme encephalopathy]
How do you diagnose lyme disease?
- look at clinical picture
- IgG and IgM antibody tests
- – get false neg in early disease and early treatment
- – get falst pos from spirochetes, viral infection, prior infection
- PCR [for arthritis]
- culture and stains not used
How do you treat lyme disease?
- oral doxycyclin for most
- amoxicillin for kids
- ceftriaxone IV with meningitis or heart block
How is leptospirosis transmitted?
- endemic to raccoons
- raccoon transmits via urine to soil/mud/water where dogs lick it up and then transmit on via saliva or urine to humans
- can get it by coming into contact with something contaminated [touching] or ingesting
How do you treat leptospirosis?
penicillin
How do you diagnose leptospirosis?
serum antibodes
What are micro properties of r. rickettsii?
- thin peptidoglycan layer so stains poorly with gram stain
- obligate intracellular organism
What is natural reservoir of r. rickettsii? vector?
hard ticks = both
- american dog tick, wood tick, brown dog tick
What is danger of r. rickettsii untreated?
23% case fatality rate
What are signs of rocky mountain spotted fever?
- 2-14 day incubation
- fever, headache, rash, myalgias
- have peripheral distribution of rash
- get multi-organ involvement: resp distress, cardio instability, renal failure, encephalitis, GI involvemtn
What do you use to stain for r. rickettsii?
- hyperimmune rabbit anti-R rickettssii antibody
What is pathogenesis of r. rickettsii?
- targets endothelial cell
- induces its own phagocytosis by triggering actin rearrangement
- releases phospholipase to excape phagosome and enter cytoplasm
- uses host cell actin to propel itself nd spread to adjacent cell
- rash caused by foci of multiple adjacent infection endothelial clels
What are effects of the damaged endothelium that r. rickettsii causes?
- get increased vascular permeability, edema, hypvolemia, hypotension, increased ADH so hyponatrema
- have procoagulant state and platelt consumption
What is immune response against r. rickettsii?
- CD8 T cells needed to clear established infection
- have protective humoral response against OmpA/B
What are micro properties of ehrlichia/anaplasma?
- tiny gram negative bacteria
- stain poorly
What is pathogenesis of ehrlichia and anaplasma? how do they differ?
- intracellular infections
- stay inside phagosome and inhiit lysosome/phagosome binding
ehrlichia chaffeenis infects monocytes
anaplasma phagocytophillum infects granulocytes
What is vector of ehrlichia chafeenis?
- lone star tick [amlyomma americanum]
What is vector of anaplasma phagocytophillum?
ixodes scapularis
What are clinical signs of rickettsia, ehrlichiosis, anaplasmosis and how do you tell the difference between them in terms of appearance and labs?
all: seasonal, incubation 5-10 days, fever, headache, myalgia [muscle pain], malaise
rickettsia: most start rash days 2-4 of illness, have macules/papules then petechiae, have low platelet, high LFT, low Na
ehrlichiosis: 30% adults, 60% children get maculo-papular rash, low WBC, low platelets, high LFT
anaplasmosis: rare to have rash, low WBC, low platelets, high LFT
What do you PCR to diagnose rickettsia vs ehrlichiosis vs anaplasmosis?
rickettsia - PCR tissue
ehrlichiosis and anaplasmosis - PCR blood
Which of rickettsia, ehrlichiosis, anaplasmosis show a low sensitivity morula on blood smear to diagnose?
ehrlichiosis and anaplasmosis
Which of rickettsia, ehrlichiosis, anaplasmosis would you use skin biopsy immuno-histochemistry to diagnose?
only rickettsia
How do you treat rickettsia, ehrlichiosis, anaplasmosis?
- immediately go on doxycycline
- do not wait for lab conformation
What is cat scratch fever? what is host? vector? signs?
- transmitted bartonella henselae by cat scratch
- host is cat, vector is cat-flea
- fever/lymphadenopathy close to exposure site
- other organs involved less commonly
- in immunocompromised can lead to bacillary angiomatosis
What are micro properties of bartnoella henselae?
- associated with kittens
- gram negative bacilli
- difficult to visualize and grow [use warthin starry silver stain]
How do you diagnose bartonella henselae?
- serology
- biopsy: granulomas and organism using special stain
What is reservoir of coxiella burnetil? how is it transmitted?
- reservoir: cattle, sheep, goats
- survives in environment and infected via inhalation
- infects macrophages
How is coxiella burnetil [Q fever] diagnosed?
- serology
- culture not done because it is a biohazard
What is brucellosis?
- reservoir in cattle, goats, sheep, swine, dogs
- symptoms of sweating, joint pain
- transmitted from ingestine or close contact [inhaled, in conjunctivae, etc]
- affect bone marrow, lymph nodes, spleen, liver
What is the disease agent associated with lyme disease? geo distribution? reservoir? vector? symptoms of disease?
agent: B. burgdorferi
distribution: northeast, midwest
reservoir: white footed mouse, deer
vector: ixodes scapularis
disease:
- early: erythema multiforme
- early disseminated: skin, heart, CNS
- late: joint, CNS
What is the disease agent associated with RMSF? geo distribution? reservoir? vector? symptoms of disease?
agent: R.rickettsii
distribution: southeast
reservoir: hard ticks [dermacentor]
vector: hard ticks
disease: fever, headache, rash, life-threatening
What is the disease agent associated with ehrlichiosis? geo distribution? reservoir? vector? symptoms of disease?
agent: E. chaffeensis
distribution: southeast
reservoir: deer, dogs
vector: amblyoma americanum
disease: fever, headache, low WBC, high LFT [liver function test], may have rash
What is the disease agent associated with anaplasmosis? geo distribution? reservoir? vector? symptoms of disease?
agent: A. phagocytophillum
distribution: northeast, midwest
reservoir: white footed mouse and other mammals
vector: ixodes scapularis
disease: fever, headache, low WBC, high LFT
