Rickettsiales Flashcards
Rickettsiales: General
Obligate intracellular
Gram Negative
Anaplasma: general
small coccoid- ellipsoid
seen as single or morulae (bacterial packets)
may cause anemia, throbocytopenia, leukopenia
Anaplasma found in
cytoplasmic vacuoles of myeloid cells, neutrophils, erythrocytes
A. marginale: transmission
Biological- hard ticks
Mechanical- athropods, less significant
A. marginale: Infects
Wild deer and domestic species
Bovine Anaplasmosis
Reportable diseases
A. marginale: Clinical signs
Anemia, icterus, splenomegaly, hepatomegaly, depression, fever, anorexia
Bovine anaplasmosis causes ___ mortality in cattle > 3 years of age.
~50%
Bovine anaplasmosis: diagnosis
Blood stains- purple structures near edge of RBC in Giemsa stains
molecular tests, serology
Bovine anaplasmosis: Treatment
Tetracyclines
Vaccine, vector control
A. phagocytophilum: Also known as
human, equine, canine granulocytic anaplasmosis
Tick-borne fever
A. phagocytophilum: reservoirs
Rodents, and wildlife (deer)
East- white-footed mouse and deer tick
West- black-legged tick
Tick-borne fever is commonly associated with ___ (disease)
Tick pyemia (staph infection)
A. phagocytophilum: pathogeneis
infection of neutrophils and eosinophils
A. phagocytophilum: Clinical signs
fever, depression, anorexia, ataxia, leukopenia, abortions, icterus
immunosuppression
hepatitis, splenomegaly, arthritis, paracortical hyperplasia of lymph nodes
A. phagocytophilum: Diagnosis
Giemsa or wright’s stained blood smear
leukemic cell culture, serology, molecular
A. platys causes
Infectious canine cyclic thrombocytopenia
A. platys: Clinical signs
1-2 week cycles
fever, lethargy, anemia, petechia, epistaxis, lymphadenopathy
A. platys often has co-infections with __
Ehrlichia canis
A. platys: transmission
Reservoirs as well
Rhipicephalus and Dermacentor
A. platys: diagnosis
Giemsa blood smear- seen in platelets
IFA, PCR
Rickettsiae: general
0.5-1 um, Gram (-), non-motile bacteria
R. rickettsii causes
Rocky mountain spotted fever
R. rickettsii: transmission
ixodes ticks- transovarial and transtadial
Dermacentor
R. rickettsii: pathogenesis
infects vascular endothelium
Necrosis, vasculitis, hemorrhages, edema, thrombosis, dyspnea
R. rickettsii: clinical signs
high fever, anorexia, vomiting, diarrhea, petechia/ecchymotic, edema, tenderness, thrombocytopenia, leukopenia
severe- necrosis of extremities (fatal)
R. rickettsii: diagnosis
Culture- embyonated yolks, cell (need glutamate)
immunofluorescence and ELISA, PCR
R. rickettsii: treatment
chloramphenicol, fluoroquinolones, tetracyclines
aggressive supportive therapy and steroids, tick control
Coxiella burnetii in humans
Q-fever
Reportable diseases
Coxiella burnetii: transmission
aerosol, mechanically
direct contact with milk products, feces, repro discharges
Coxiella burnetii: Pathogenesis
infection of vascular, renal, and reproductive epithelia
splenomegaly, hepatitis, fever
Coxiella burnetii: Immunity
whole cell killed vaccine
Phase I and II
Coxiella burnetii: diagnosis
Tissue stains- gimenez, giemsa, Ziehl Neelsen
culture in cell or egg, serology, PCR
Coxiella burnetii: Treatment
antimicrobials are not effective
Chloroquine and Tetracycline
Ehrlichiae: general
WBC obilgate intracellular
multiply in intracellular vesicles
Ehrilichia canis: causes
canine monocytic ehrlichiosis
Ehrilichia canis: transmission
Brown dog tick
Ehrilichia canis: Acute clinical signs
Pancytopenia
fever, malaise, depression, inappetance, weighloss, lymphadenopathy, epitaxis
Ehrilichia canis: Chronic clinical signs
Dyspnea, enlarged spleen, liver, and lymph nodes
polyarthritis, CNS signs, pulmonary infiltration
Ehrilichia canis: diagnosis
Giemsa- stained buffy coat
culture, IFA, PCR
Ehrilichia canis: treatment
tetracyclines and imidocarb in acute
doxycycline in late stage - poor prognosis
Tick control
E. chaffeensis: features
Human monocytic ehrlichiosis
American dog tick (Dermacentor)
reservoir- deer
E. ewingii: features
canine granulocytic ehrlichiosis
Lone star tick (Amblyoma americanum
E. ruminantium: causes
African heartwater
reportable disease
E. ruminantium: transmission
only by parental intro into blood, Amblyomma
E. ruminantium: replication
replicates in reticuloendothelial cells
E. ruminantium: clinical signs
Per- fever and sudden death
A- fever and CNS signs, death in 2-10 days, mortality 6-80%
Sub- hydropericardium, hydrothorax, congestion, splenomegaly, hemorrhage
E. ruminantium: diagnosis
giemsa-stain
molecular and serology
E. ruminantium: treatment
tetracyclines
tick control, vaccine
Neorickettsia: general
small, non-motile, coccoid, intracytoplasmic, Gram negative
cannot be cultivated in cell-free media or embryo eggs
Neorickettsia: vectors
Flukes
Neorickettsia helminthoeca causes
Salmon poisoning disease
mild form- Elokomin fluke fever
N. helminthoeca: Pathogenesis
Infects lymphoreticular tissues- LN, peyer’s patches
Target- canine mononuclear cells
Only obligatory helminth-borne pathogenic bacterium
Nanophyetus salmincola
by transovarial passage
N. helminthoeca: Clinical signs
Hemorrhagic diarrhea, lymphadenopathy
fever, depression, dehydration, anorexia, weightloss
N. helminthoeca: diagnosis
Fluke detection
IFA, PCR
N. helminthoeca: treatment
supportive care, tetracyclines, penicillin G
do not allow consumption of raw fish, no vaccine
recovered animals are immune
N. (Ehrlichia) risticii causes
Potomac horse fever
a.k.a- Equine monocytic ehrlichiosis, Equine scours
N. (Ehrlichia) risticii: target cells
monocytes, tissue macrophages, intestinal epithelial cells
N. (Ehrlichia) risticii: clinical signs
acute, watery diarrhea
fever, anorexia, mild colic, depression, dehydration, laminitis, leukopenia
mortality: 5-30%
N. (Ehrlichia) risticii: diagnosis
History, wright-stained blood smears
IFA, ELISA, PCR
N. (Ehrlichia) risticii: treatment
vaccine is questionable
tetracyclines, oxytetracyclines
Aegyptianella pullorum causes
Aegyptianellosis
affects poultry and wild birds
A. pullorum: vectors
Argus ticks
A. pullorum: Clinical signs
ruffled feathers, anorexia, diarrhea, anemia, hyperthermia
hepatosplenomegaly, punctiform hemorrhage
A. pullorum: treatement
tetracyclines
tick control
