29 – Coxiella, Borrelia and Bartonella Flashcards
Coxiella microbiological characteristics
- Obligate intracellular parasites
- Doesn’t stain using Gram-stain
- Worldwide distribution EXCEPT New Zealand
- Not culturable using standard techniques
- Biocontainment level 3
- *requires specialized conditions in vitro (inoculation of embryonated eggs)
Borrelia microbiological characteristics
- Large spirochetes
- Small linear chromosome
- Biocontainment level 2
- On both continents (Europe and USA) for over 100 years
Bartonella microbiological characteristics
- Small Gram-negative coccobacilli
- Biocontainment level 2
Coxiella natural host or habitat
- Obligate parasite: host associated
- Infects wide variety of species
- Shed in milk, urine, feces, amniotic fluids at parturition
- Can survive in environment up to 150 days
Borrelia natural host or habitat
- Obligate parasites: host associated
- Associated with reservoir hosts and arthropod vectors
o Highly adapted to their specific arthropod vector - Transmission via tick bites=most likely by nymphs
Bartonella natural host or habitat
- Facultative intracellular parasite
o Erythrocyte and endothelial cell pathogens - Have principle animal reservoir
- Spread through vectors
- *Generally mild disease in reservoir host, pathology when incidental host infected
Coxiella burnetiid virulence factors
- Little known
- LPS: phase variation (antigenic variation that masques it from the immune system)
Borrelia burgdorferi virulence factors
- Outer surface proteins: attachment in tick host, allows organism to persist in gut between meals
- Surface lipoproteins: stimulate inflammation
- Porin-like proteins: adhesion
- Flagella; motility
Bartonella spp. virulence factors
- Type 4 secretion systems
- Bartonella effector proteins (BEPS): secreted into host cells and modulate physiology in favour of bacteria
o Induction of phagocytosis by host cells
o Prevention of apoptosis
Coxiella burnetii is a generalist parasite of eukaryotic cells and is found in
- Arthropods
- Reptiles
- Birds
- Mammals
What is Coxiella burnetii the agent of?
- Q fever
o Short ‘query’ fever
When Coxiella burnetii is present, there are high concentrations in placenta and fetal tissues
- Animals frequently eat these after birth
- Passes through GIT
- Excreted in feces
- Can be aerosolized as dust
Aerosol transmission of Coxiella burnetii is very important
- Very low infectious dose
- Enters lungs
- Replicates in pulmonary macrophages
- Disseminates throughout the body
Interesting life cycle of Coxiella burnetti (?)
- Small cell variant ‘eaten’ by macrophage
- Vacuoles acidifies, stimulating development of large cell variants
- By 2 days parasitophorous vacuole contains lots of replicated large CV
- By day 6, small CV reappear
- By 12 days, host cell lyses and small CV released
Coxiella burnetii in domestic animals are mild or non-apparent: clinical sings relate to sites of localization (ruminants)
- Reproductive and mammary tract: abortions and shedding in milk
o Sporadic abortions: sheep, goats, cattle, cats
o Placentitis
o fetal pathology: many
Fetal pathology with Coxiella burnetii (ruminants)
- hepatitis
- myocarditis
- interstitial pneumonia
How do you control Coxiella burnetii? (ruminants)
- Segregation of parturient ruminants
- Careful disposal of tissues
Vaccination for Coxiella burnetii (ruminants)
- Inactivated vaccines available
Coxiella burnetii in dogs and cats
- Most common sublclinical
- Affected dogs=SPLENOMEGALY most common
- Cats=abortions
o Has been associated with human outbreaks
o See fever, lethargy, anorexia 2 days following experimental infection
What does Coxiella burnetii in humans cause?
- Q-fever
- Incubation period: 3 weeks
- 50% infected=asymptomatic
- Acute febrile illness (flu like)
- Case fatality <2% of hospitalized patients
- *NOT notifiable in Canada
What are some serious complications that can occur with Coxiella burnetii in humans?
- Pneumonia
- Granulomatous hepatitis
- Myocarditis
- Abortion
There was large, multiyear outbreaks of Coxiella burnetii in humans in the Netherlands
- 2005: dairy goats
- 2007: human infections spiking
o Living downwind with important - Clusters of infections associated with psychiatric patients who had contact with lambs as part of therapy
How was Coxiella burnetii in humans in the Netherlands brought under control?
- Vaccination
- Manure management
o Removal
o Pasteurization
o NOT spreading on fields - Bulk tank milk surveillance
- Massive culling
Coxiella burnetii in humans is often acquired as occupational disease
- Farmers
- Abattoir workers
- Vets
- Lab workers
- *FOODBORNE: unpasteurized products
- *rarely associated with cats
How do you treat Coxiella burnetii in humans?
- Doxycycline
How do you prevent Coxiella burnetii in humans?
- Vaccine for high risk workers
Who are the only competent vectors of Borrelia burgdorferi, Lyme Disease?
- TICKS: North America
o I. scapularis
o I. pacificus - *ticks infected by biting reservoir host
Transmission of Borrelia burgdorferi, Lyme disease: ‘timeline’
- Not instantaneous
o Can take up to 24hrs for transmission to occur - Co-infection with other vector borne diseases is common
Where Is LYME mostly in North America?
- In the east
- Technically broad rang
- I. pacificus likes to feed on lizards=Borrelia don’t amplify as efficiently
What is the most common sign of Borrelia burgdorferi in dogs?
- NOTHING
o Not usually cause of disease
What may be seen in affected dogs with Borrelia burgdorferi?
- Intermittent recurrent lameness: polyarthritis is best documented
- Fever
- Anorexia
- Lymphadenopathy
- Swollen joints
- *fatal renal failure: immune complex deposition in kidney
Clinical disease of Borrelia burgdorferi does NOT often manifest in cats
- Seroconversion occurs, but cats seem somewhat RESISTANT
- If infected=similar signs as dogs
What is the treatment of Borrelia burgdorferi in dogs and cats?
- Early treatment is important
- Doxycycline, amoxicillin, azithromycin recommended
How do you control Borrelia burgdorferi in dogs and cats?
- Acaricides
- Removing ticks promptly
- Vaccination
o Variety of product available
Borrelia burgdorferi, Lyme disease in humans
- Does cause serious illness
- Symptoms 3-30 days post infection
- Chronic signs occurring days to months later
Symptoms of Borrelia burgdorferi, Lyme disease in humans 3-30 days post infection
- Fever, chills, swollen lymph nodes
- Characteristic erythema migrans rash (TARGET)
Chronic signs of Borrelia burgdorferi, Lyme disease in huamns
- Severe headache
- Arthritis
- Facial palsy
- Pain
- Heart palpitations
- Dizziness
- Inflammation of brain
- Nerve pain
Canada distribution: Lyme disease
- Parts of BC, MB, S. ON, QB, Nova Scotia
- *locally acquired disease not reported in SK or AB
- Over time: appears to be increase
- **highest frequency in ON (related to size of population
- **highest incidence in Nova Scotia
Clinical significance of B. afzelli
- Cause of Lyme in Europe
Clinical significance of B. mayoni
- Novel one causing Lyme disease
Clinical significance of B. lonstari
- Vectored by Amblyoma americanum
- Associated with southern tick rash illness in people, birds and deer
Clinical significance of B. theileri
- Vectored by Rhipicephalus spp.
- Cause of bovine borreliosis (+sheep and goats)
Bartonella henselase in cats
- Clinical signs rare
- 30-40% of clinically healthy shelter cats are carriers
- Lack of evidence for clearance of Bartonella from treated cats
Bartonella henselase in EXPERIMENTALLY infected cats, signs:
- Transient fever
- Papules/abscesses at site of inoculation
- Lymphadenopathy
- Myalgia
Bartonella spp. in dogs
- Many implicated
- Endocarditis: B. vinsonii + more
- Hepatitis: B. henselae
- *flea and tick prevention is important
- If clinical signs: treat with LONG DURATION ANTIMICROBIALS
o Enrofloxacin
o Doxycycline
o Amoxicillin
o Rifampin
Bartonella henselae, cat scratch disease (CSD) in humans
- Important zoonoses: people infected following cat scratches
- Symptoms develop 1-3 weeks post exposure
- Can see bacillary angiomatosis
o Angiogenesis and lesions on skin
What are the symptoms 1-3 weeks post exposure of Bartonella henselae, cat scratch disease (CSD) in humans
- Fever
- Papule or pustule at site of scratch
- Enlarged, painful lymph nodes
What does Bartonella quintana cause in humans?
- Trench fever: name from soldiers in WWI
o Bacteremia
o Localized tissue infections
o Endocarditis
Where is Bartonella quintana in humans reemerging?
- People affected by extreme poverty in developing countries AND homeless (developed countries)
Bartonella quintana in humans
- Vectored by human body louse
- Humans only confirmed reservoir
- Also reported in cats
What does Bartonella baciliformis cause in humans?
- Carrion’s disease
o Hemolytic anemia
o Localized tissue infection
o Angiomatosis - *biphastic disease
Carrion’s disease from Bartonella baciliformis in humans is a biphasic disease
- First phase: erythrocyte infection, anemia and transient immunosuppression
- Second phase: nodular dermal eruptions occur as a result of vascular proliferation
What is Bartonella baciliformis transmitted by?
- Sandflies in Andes Mountains (W. South America)
Coxiella: sample collection and handling
- Blood
- Serum
- Placental tissues
Borrelia: sample collection and handling
- Blood
- Biopsies of cutaneous lesions
Bartonella: sample collection and handling
- Blood
- Tissues collected on necropsy
o Vegetations in cases of endocarditis
Coxiella burnetii: Lab ID
- Culture only done in specialized laboratories
- PCR: detect organism in early stage
- Immunohistochemistry of biopsy specimens
- Serology: acute and convalescent
o Cross reactions with many species
Bartonella spp: Lab ID
- can be cultured
- PCR
- Serology: most common
o Beware of cross-reactive Abs
Borrelia: Lab ID
- Serology
- Antigen capture ELISA
- Fluorescent Ab
- PCR
Borrelia: Lab ID with serology
- Interpretation difficult, many seropositive are not clinically affected
- Validation challenging b/c of lack of culture positive GOLD standard cases
Coxiella burnetti: zoonotic/interspecies transmission
- Capable of causing lab acquired infections
o Fatal infections are reported - Potential BIOLOGICAL WEAPONE
o Aerosolized organism with aim of debilitating large population
Borrelia burgdorferi: zoonotic/interspecies transmission
- NOT acquired directly from infected animals
o All about vectors
Bartonella spp: zoonotic/interspecies transmission
- avoid cat scratches/bites (protective behaviours #1!)
- flea and tick control important
- testing and decolonization therapy NOT recommended for healthy cats
Treatment options
- SUCEPTIBILITY TESTING IMPOSSIBLE
C. burnetii treatment
- Doxycycline
Borrelia treatment
- Doxycycline, beta-lactams
- Depends on species
Baronella spp. treatment for animals
- Enrofloxavin
- Doxycycline
Baronella spp. treatment for humans
- Azithromycin
- Doxycycline
- Aminoglycosides
