Rickettsia and Chlamydia Flashcards
T/F: Rickettsia and chlamydia spps are obligate extracellular pathogens
False
OBLIGATE INTRACEULLUR
Rickettsia and chlamydia are gram _______, organism that have _________ morphology
Gram NEGATIVE
Coccobacilli
What antimicrobial are all rickettsia and chlamydia spps susceptible to?
TETRACYCLINE
What genera are included in the family Anaplasmataceae?
What cells do they infect?
Anaplasma
Ehrlichia
Neorickettsia
*infect haematopoietic (cells produced in bone marrow) cells of vertebrate hosts
Rickettsia spps have a tropism for what cells?
Endothelium
T/F: Rickettsia are vector borne pathogens
TRUE
live in an arthropod host –> TICKS
What bacterium causes Rocky Mountain Spotted Fever?
Who does it affect?
Rickettsia rickettsia
Humans and Dogs
What clinical signs may you see in a dog with Rocky Mountain Spotted Fever?
Bacteria invades endothelium –> hemorrhage - petechial, edema, vasculitis, fever, depression, tissue necrosis (from poor blood supply),vasocontriction
What other pathogen has similar clinical sign to those seen with RMSF (R. rickettsia)?
Ehrlichia
What is the best way to diagnose rickettsia?
PCR is best
Skin tissue FA
What arthropod is the vector for Rickettsia felis? What dz does it cause
Cat flea
“Flea borne spotted fever” in humans
What bacteria are part of the Typhus group of rickettsia? What dz do they cause?
R. prowazekii - Epidemic typhus in humans (spread by human and flying squirrel louse)
R. typhi - Murine typhus (opossum-flea cycle)
Oreintia tsutsugamushi - Srub typhus (chigger mites - bird/rodents cycle)
T/F: Anaplasmataceae members are of zoonotic potential
TRUE
Anaplasma phagocytophilum causes what dz and in whom?
Agent of Human granulocytic Ehrlichiosis
What cells can you find Anaplasma phagocytophilum in?
Neutrophils
What arthropod is responsible for transmission of Anaplasma phagocytophilum? What other dz/pathogen does it transmit?
Ixodes tick
Also transmits Lyme dz (B. burgdorferi)
Anaplasma phagocytophilum is maintained in..?
What host does it infect that is of veterinarian concern?
Ixodes and small mammals
Causes necrotizing vasculitis in Horses - usually mild, but can occasionally be fatal (icterus, edema, ataxia –> DIC)
T/F: performing a snap test to dx anaplasmosis in an area with more than one spps is an effective dx method
FALSE
It does not differentiate what spps - need PCR
**Snap is proficient if only one spps of anaplasma is endemic in that geographical area
Who is the only known reservoir of Anaplasma platys?
What cells does it infect?
DOGS
Platelets
What pathogenesis does A. platys cause?
Fever, uveitis, petchia, thrombocytopenia –> can be serious in surgical cases - poor clotting
T/F: Anaplasma platys has a wide host range
FALSE
dogs only (for now…)
What animals are most susceptible to Anaplasma marginale infections?
Old ruminants
Anaplasma marginale can be found in what cells?
Found in the periphery of erythrocytes
T/F: A. maginale is the number once cause of anaplasmosis in ruminants
TRUE
T/F: A. marginale is similar to babesia but is not a pathogen that is part of the “tick cattle fever” complex
FALSE
_________ is a pathological finding on PM exams of cows that have died from A. marginale infections. This specific finding can be found in animals with Anthrax and babesia infections.
SPLENOMEGALY
*for A. marginales - the spleen is enlarged from harboring infected erythrocytes
What bacteria causes Tropical Pancytopenia, in what host, and how is it transmitted?
Ehrlichia canis
canine
brown dog tick
T/F: In dogs with tropical pancytopenia, lymphocytosis and hyperglobulinemia is characteristic
TRUE
Is tropical pancytopenia a fatal disease?
Depends! It ranges from asymptomatic to fatal
What cells does Ehrlichia canis infect?
Endothelial cells, mononuclear cells, lymphocytes
E. ewingii causes …?
Canine granulocytic ehrliciosis
What is the causative agent of “heart water disease” and who does it infect?
Ehrlichia ruminantium
Ruminants
T/F: The ixodes tick transmits heart water disease
FALSE
Amblyoma
T/F: Ehrlichia ruminatium outbreaks occur from time to time in the US.
FALSE
**THIS IS A REPORTABLE FOREIGN DZ****
Where does Ehrlichia ruminatium replicate in the host and what pathogenesis does it cause?
Replication in macrophages and endothelial cells (Brain epithelial cells)
Causes pericardial edema, cerebral edema, neurological signs –> DEATH
How do you dx Ehrlichia ruminatium?
PM - brain squash smear
Potomac horse fever is caused by what pathogen and what is the mode of transmission?
Neorickettsia risticii
Transmitted via ticks and flukes (of brown bats) - aquatic snails/insects are part of the life cycle
T/F: Neorickettsia risticii causes mild disease in horses
FALSE – fatal dz
What clinical signs may be observed in a horse with Potomac horse fever?
Where does the bacteria replicate?
Replication in macrophages and enterocytes
Hemorrhagic dhr, anorexia, leukopenia –> death
What is the causative agent for Salmon poisoning in dogs and how do they get it?
Neorickettsia helminthoeca
Dogs get this pathogen by eating salmon that have infected flukes
What clinical signs will be observed in a dog with Neorickettsia helminthoea?
Hemorrhagic gastroenteritis, fever, depression
fatal if untreated
How do you dx salmon poising in dogs and what drug(s) are used to treat it?
Clinical signs, history, and fecal sediment for fluke eggs
Tetracyline and praziquantal
supportive care prn
T/F: Chlamydia is dimorphic
TRUE
What stage of chlamydia is infectious?
Extracellular - non-replicating phase aka elementary bodies
What is the non infective stage of chlamydia?
Intracellular replicating aka reticulate body
T/F: Animals get chlamydia via direct contact, ingesting, or inhaling reticulate bodies
FALSE
Elementary bodies are infectious!!
T/F: Chlamydia psittacia is zoonotic and is BSL4 pathogen
FASLE
It is zoonotic and BSL3
REPORTABLE
Chlamydia abortus causes abortion in what animals?
Ruminants
Chlamydia pecorum causes what? Who is the host?
Polyarthritis and polyserositis in ruminants
“stiff lamb dz” and sporadic bovine encephalomyelitis
Chlamydia are parasites of _________
Epithelium
Chlamydia felis causes what in cats?
Conjunctivitis and rhinitis
Who does Chlamydia pneumonia infect?
Humans and Koala bears
How is C. psittaci transmitted?
Elementary bodies are shed in the feces of carries (birds) and then they are inhaled into the lungs or ingested
What spps of chlamydia causes multi organ septicemia that can result in hepatomegaly, splenomegaly, and fibrinous pericarditis
Chlamydia psittaci
How can you diagnose C. psittaci?
Direct smear using Giemsa stain, PCR, FA
What pathogen causes Q fever (Queen fever)?
Coxiella burnetii
T/F: Coxiella burnetii is a zoonotic pathogen that has bioterrorism potential
TRUE
Coxiella burnetii is endemic in what hosts?
cattle/sheep/goats
What is the MOI of Coxiella burnetii?
This pathogen is resistant in the environment (endospore-like) and is shed in milk, urine, and feces (of carriers which can be asymptomatic). Infection occurs via **inhalation, ingestion, direct contact
T/F: Pasteurizing milk should kill Coxiella burnetii
TRUE
What clinical signs might you seen in a human patient with Q fever?
Signs in a ruminant?
prolonged flu like illness, hepatitis, endocarditis
goat/sheep/cattle - are often subclinical female carriers but may experience placentitis and abortion
How do you dx and tx Q fever?
Dx: PCR
Tx: **early detection is key - tetracycline and fluroquinolones are drug of choice
**good hygiene
Coxiella burnetii is an obligate ________ pathogen.
INTRACELLULAR
T/F: Chlamydia is referred to as energy parasites bc they create a lot of ATP
FALSE
bc they DO NOT generate ATP
