Systemic infections 1 Flashcards
systemic infection variation Ehrlichia spp. Rickettsia rickettsia, Francisella tularenis, Systemic mycoses
- not rapidly fatal but for some animals enough systems effected that get worse -> euthanasia
- severity of signs depends on individual animal
Ehrlichia spp. fam
family- anaplasmataceae
Ehrlichia spp. general characteristics
- obligate intracell bacteria
- 2 membranes
- no cell wall btwn membranes
- lack lipopolysaccharide
- obligate aerobe
Ehrlichia species
- Ehrlichia ewingii
- Ehrlichia chaffeensis
- Ehrlichia canis
Ehrlichia spp. lifecycle
- obligate pathogeen of abcs found in granulocytes and monocytes
- if in macrophage enter in special phagosome no phagosome lysosome fusion bc alters phagosome
Ehrlichia transmission
- infected animals = source of bacteria
- transmitted by ticks (3-6hrs for transmission)
Ehrlichia spp. primarily a pathogen of
dogs
Ehrlichia ewingii affects who, transmitted by what
- transmitted by lone start tick
- dogs
- zoonotic
ehrlichia ewingii causes what
- found in granulocytes, cause canine granulocytic ehrlichiosis
- mild dx usually som animals no signs of dx
Ehrlichia chaffeensis transmission
- transmitted by lone star tick
ehrlich ewingii vs ehrlich chaffeensis common
ewingii more common
Ehrlichia chaffeensis causes what
- mild dx or no dx
Ehrlichia chaffeensis affects who
- dogs, other animals (deer)
- z (from tick not dog)
ehrlichia canis transmitted how
- brown dog tick
ehrlichia canis causes what
- infects monocytes
- canine monocytes ehrlichiosis
- causes more severe dx in dogs that other ehrlichia species (but there are serapes animals with no signs)
ehrlichia spp. signs acute
- 2-4 weeks after bite
- fever, lymphadenopathy, inap, depression (non-specific dx)
- animals often asymptomatic carriers
ehrlichia spp. signs chronic
- months to years after initial infection
- fever, inap, weight loss
- epistaxis
- meningitis (neuro)
- glomerulonephritis
- thrombocytopenia -> bleeding type lesions
ehrlichia spp. chronic signs most common with
- ehrlichia canis
- certain breeds (g shep and huskys)
ehrlichia spp. chronic necropsy
- hemorrhages (petichea and echomosis throughout)
Ehrlichia spp. diagnosis
- pcr
- serology (snap tests)
ehrlichia spp tx
- tetracycline tx
- prevention: prevent tick exposure
Rickettsia rickettsii general characteristics
- gram neg
- obligate intracell
- obligate aerobic
- coccobacillus
- zoonotic
rickettsia rickettsii found where
- inside endothelial cells
- mult in endothelia cells, move around on acting filaments, replication can -> damage in endothelium -> leakage
rickettsia rickettsii inhabitant of, transmission, cause dx in
- natural inhabitant of rodents
- transmitted by tick bites
- cause dx in dogs (Rocky Mountain spotted fever)
rickettsia rickettsii transmitted by which ticks, takes how long
- dermacentor
- rhibacephalus
- 5-20hrs to transmit
rickettsia rickettsii causes what
- Rocky Mountain spotted fever in dogs
- RARELY also in cats
- zoonotic
Rocky Mountain spotted fever signs initial
- HIGH fever = big finding
- not eating/ v+/d+
- hemorrhagic mucous membranes
- tenderness over lns, joints, muscles
rickettsia rickettsii zoonosis details
ppl get it from ticks spreading from same rodent source dogs get it from not from dogs
Rocky Mountain spotted fever signs progressed
- petechial and ecchymotic hemorrhaged develop later on ocular, oral, and genital mucous membranes in dogs
- neuro signs
rickettsia rickettsii diagnosis
- serological tests
- pcr
- VERY hard to culture
rickettsia rickettsii tx/ prevention
- tx: tetracycline, fluoroquinolones
- prevent tick exposure
francisella tularensis general characteristics
- gram neg
- bacillus
- aerobic
- Z
- R
- POTENTIAL BIOTERRORISM
Francisella tularensis important type
Francisella tularensis spp. tularensis (type a strain) = most virulent= predominates in us
Francisella tularensis natural inhabitant of
rabbits and hares
- some develop dx most = asymptomatic carriers
francisella tularensis multiply where
- inside amoeba
- inside animal mult inside macrophages
francisella tularensis transmission
- arthropods (ticks and flies)
- ingestion
- direct contact
francisella tularensis causes what in who
- causes tularemia
- not that common in animals often asypt or mild signs
- cats most commonly
- rarely sheep and dogs
- z
francisella tularensis in cats presentation
- fever
- regional lymphadenopathy
- can involve spleen and liver in more severe case
francisella tularensis dogs
usually show nothing or v mild signs
francisella tularensis sheep
seen in sheep heavily infected with ticks
francisella tularensis zoonosis
- Z
- R
- POTENTIAL BIOTERRORISM
- v severe in ppl
- found throughout country
francisella tularensis diagnois
- serology
- ln aspriate/ tissue smamples
- grow on bld agar w and w/o cysteine
- look at spleen and liver at necropsy
systemic mycoses organisms of intrest
- blastomyces dermatitidis
- histoplasmosis capsulatum
- coccidiodes immitis/ posadasii
systemic mycoses general
- dimorphic mold in enivonrment w/ diff enivonrmntal preferences
- obligate aerobes
systemic mycoses natural inhabitant of
soil
systemic mycoses transmission
- primarily inhalation
- rarely through wounds
systemic mycoses contagious
not really contagious if mult animals in same area have this then exposed to same source bc in body go from mold then go to yeast form which doesn’t really spread easily
systemic mycoses general signs
- long-term
- nonspecific signs
- v hard to differentiate which fungi causing it and some signs can look like bacteria as well, key is geographic location and no response to antibacterials
blastomyces dermatitis id
- yeast with broad based buds in parasitic form
blastomyces dermatitis vs cryptococcus
blastomyces broad based buds cryptococcus narrow based buds
geographic distribution blastomyces dermatitis
- primarily eastern part of country; endemic where we are but not common here
- like enivomrnet w/ soils w/ high organic content, acids, ph, abundant moisture
- dogs digging near water tend to be prone to this
blastomyces dermatitidis signs
- anorexia, weight loss
- dyspnea
- ocular dx -> retinal detachment (*more common w/ this one than other two)
- lameness
- skin lesions in dogs
blastomyces dermatitis affects who
- mostly dogs
- rarely dx in cats
diagnosis blastomyces dermatitidis
- broad based yeasts in lesions, tissue specimines
- sabouraud dextrose agar room temp
- bld agar 37 degrees
- use both types agars diff temps to demonstrate dimorphism
blastomyces dermatitidis tx
- itraconazole
- amphotericin B
- tx for 3-6 months
histoplasma capsulatum general characterisitcs
- yeast in parasitic form
- facultative intracell pathogen of phagocytic cells (macrophages)
- do not have capsule just thick cell wall that resembles one
histoplasmosis capsulatum found where
- Mississippi and Ohio water shed
- bird or bat guano
histoplasmosis capsulatum affects who
- dogs
- cats
histoplasmosis capsulatum signs
dogs- lethargy/ anorexia/ weight loss/ d+/ dehydration/ anemia/ enlarge lymphoiid organs
cats- depression/ weight loss/ fever/ DYSPNEA/ TACHYPNEA/ enlarged lymphoid organs
generally wide range of non specific signs for both
histoplasmosis capsulatum signs diff
- dogs more d+ with histoplasmosis capsulatum than other systemic mycoses but not significant enough finding to r/o other two
cats vs dogs presentation histoplasmosis capsulatum
cats > resp signs bc inhale into lungs
histoplasmosis capsulatum diagnosis
- aspirates contain yeast cells inside phagocytic cells (free yeast only in phagocytic cells not in tissue)
- grow on sabouraud dextrose agar at room temp and blood agar at 37 C to demonstrate dimorphism
histoplasmosis capsulatum tx
- azaleas or azaleas plus amphotericin b
- antifungas long term, 4-6 months
coccidioides immitis/ posadasii general characteristics
- spherules in parasitic form, filled with endospores
- looks like coccidia which = why have this name
coccidioides immitis/ posadasii location
- not found in this part of country
coccidiodes immitis/ posadasii enivonrment
- molds in environment
- fungi breaking up into individual cells
- parasitic forms in spirals filled w/ endospores
coccidiodes immitis/ posadasii transmission
Envionrment -> inhaltion -> lung -> enlarge into sphirules -> internal divisions in sphirules -> mature into individual celsl called endospores and sphereule wall breaks and within animal endospores repeate the cycle
coccidioides immitis/ posadasii location
- in western us and some areas in Mexico
- live in lower senoran life zone (hot arid environment w/ rare freezes w/ occasional rains, tends to be dry enivonrment prefers alkaline soil
coccidiodes immitis/ posadasii affects who
dogs, cats horses
* if dog hasn’t been in south west doesn’t have this*
coccidiodes immitis/ posadasii signs dog
- fever, anorexia, weakness, weight loss, lameness, dpression
coccidiodes immitis/ posadasii signs horses
- weight loss, cough, muscle pain, superficial abcesses
coccidiodes immitis/ posadasii signs cats
- skin lesions, fever, inappetence, weight loss (skin lesions most common sign in cats)
coccidiodes immitis/ posadasii diagnosis
- spherules can be seen in tissue specimines
- grown on sabouraud dextrose agar at room temp
coccidiodes immitis/ posadasii spherules
can be infectious to ppl = Vally fever in ppl
coccidiodes immitis/ posadasii tx
- fluconazole, ketaconazole, or itraconazole
Ehrlichia spp. spread by what
ticks
blastomyces dermatitis what sign most common
ocular w/ dogs but can’t r/o the other two off of this
which systemic dxs from this section cause bleeding
- Ehrlichia canis
- Rickettsia rickettsii
systemic pathogens that -> general signs
- Ehrlichia spp.
- Rickettsia rickettsii
- Francisella tularensis
- Blastomyces dermatidis
- histoplasmosis capsulatum
- coccidiodes spp.
why geography to tell systemic pathogens with general signs apart
live in diff places bc
- vectors only in certain places
- prefer certain environments (fungi)
