Obligate Intracellular Bacteria Flashcards
General characteristics of rickettsiales group
small, aerobic
obligate intracellular
gram neg
How do rickettsiales survive inside host cells?
infect immune cells
avoid destruction by lysosomes
How are rickettsiales bacteria transmitted?
vectors: ticks, fleas, flukes
Virulence and pathogenicity of rickettsiales
endotoxins
form immune complexes and trigger hypersensitivity reactions
E. canis host
dog, human, cat, primates
E. ewingii host
dog, human, white-tailed deer
E. ruminatium host
ruminants
E. canis host cell
monocytes, macriohages, lymphocytes
E. ewingii host cell
neutrophils
E. ruminantium host cell
vascular endothelial cells, neutrophils
E. canis reservoir host
mutiple
wild canids and primates
E. ewingii reservoir host
white-tailed deer
E. ruminantium reservoir host
wild and domest ruminants
Disease caused by E. canis
Canine monocytotropic ehrlichiosis
Disease caused by e. ruminantium
heartwater
Disease caused by E. ewingii
Canine granulocytic ehrlichiosis
Distribution of E. canis
World wide
Clinical forms of E. canis
acute
subclinical
chronic
can be seen in cats too
Clinical signs of acute E. canis
fever
anorexia
lymphadenopathy
bleeding
thrombocytopenia
Describe subclinical E. canis
PCR neg but bacteria are still present in low/undetectable levels
Clinical signs of chronic E. canis
severe thrombocytopenia
anemia
leucopenia
bone marrow hypoplasia
Diagnosis of E. canis
history of tick bite
clinical signs
epistaxis
thrombocytopenia
IFA
ELISA
PCR
culture and isolation
snap tests
blood stains
Treatment of E. canis
doxycycline for 4 weeks
transfusion
Prevention of E. canis
tick control
Clinical signs of E. ewingii
mild fever
arthitis
muscular stiffness
Diagnosis of E. ewingii
PCR
snap test
Treatment of E. ewingii
doxycycline
Prevention and control of E. ewingii
tick control
NO VACCINE
Causative agent of rocky mountain spotted fever
rickettsia rickettsii
Where is rocky mountain spotted fever endemic?
USA, south america and mexico
How is rickettsia rickettsii transmitted?
ticks
Is rickettsia rickettsii zoonotic?
yes - infects dogs and humans
What is the target cell of R. rickettsii?
vascular endothelial cells
Reservoir for R. rickettsii
rodents and ticks
Where does R. rickettsii localize within the tick?
midgut, small intestine and ovaries
Where does R. rickettsii localize in mammals?
endothelial cells
What are the two forms of rocky mountain spotted fever in dogs?
subclinical and acute
Clinical signs of acute rocky mountain spotted fever in dogs?
loss of appetite
fever
depression
edema
neurological signs
anemia
rash on the ear
petechiae on oral mucosa
testicular inflammation
Diagnosis of rocky mountain spotted fever
history, PE, clinical signs
IFA, IHC
PCR
culture - not routinely performed
Treatment and control of rocky mountain spotted fever
doxycycline given within 5 days of onset
tick prevention
NO vaccine
Causative agent of Q Fever
Coxiella burnetii
Hosts/reservoirs of Q fever
ruminants
zoonotic
Can coxiella burnetii be excreted from the host?
yes - excreted in milk, urine and feces
Clinical signs of Q fever
mostly subclinical
abortion
sever placentitis
malaise
anorexia
Treatment and control of Q fever
tetracyclines
supportive care
quarentine
proper management/sanitation
vaccination