RICKETTSIA Flashcards
Simplest bacterial form and considered as transitional organism between bacteria and virus.
RICKETTSIA
Fastidious bacteria and obligate, intracellular parasites.
RICKETTSIA
Rocky mountain spotted fever (RMSF) most
serious rickettsial infection
SPOTTED FEVER GROUP:
Gram-negative cell wall, motile, will not grow in
cell-free media
RICKETTSIA
Multiply
Binary fission
Survive briefly outside of their host
RICKETTSIA
Small, pleomorphic, gram-negative
bacilli. They do not undergo any intracellular
developmental cycle
Microscopy of RICKETTSIA
R. prowazekii and R.
rickettsii.
Agents of bioterrorism
humans are the accidental hosts and
ticks are the main vector and reservoir.
Rocky mountain spotted fever
Rashes developed on the palms of the hands
and soles of the feet
SPOTTED FEVER GROUP
Rashes that are similar to
RMSF but on face.
Boutonneuse fever
(black spot): present in BF
Tache noires
rashes face and extremities
Rickettsialpox
characterized by rashes on
the face, palms, and soles of feet of the sick.
Endemic typhus
- Rashes are not commonly observed
- Inhalation of aerosol from dried infected flea
feces is also a mode of transmission of
Rickettsia typhi infection.
TYPHUS GROUP
Boutonneuse fever
or
Mediterranean
spotted fever
Rickettsia
conorii
Ticks
(Rhipicephalu
s sanguineus)
Rickettsia
conorii
Rocky Mountain
Spotted Fever
Rickettsia
rickettsii
Wood ticks
(Dermacentor andersoni)
Dog ticks
(Dermacentor
variabilis)
Brown Dog
ticks
(Rhipicephalu
s sanguineus
and Amblyomma
cajennense
Rickettsia
rickettsii
Rickettsial pox
Rickettsia akari
Mouse mite
(Liponyssoide
s sanguineus)
Rickettsia akari
Flea-borne spotted
fever
Rickettsia felis
Flea bite or
feces
Rickettsia felis
Epidemic
typhus/BrillZinsserdisease
Rickettsia
prowazekii
Body louse
(Pediculus
humanus
corporis)
Squirrel flea
(Orchopeas
howardi)
Squirrel louse
(Neohematopi
nus
sciuriopteri)
Rickettsia
prowazekii
Scrub typhus
Orientia
tsutsugamuchi
Chigger
(Leptotrombid
ium deliense)
bite
Orientia
tsutsugamuchi
Human Monocytic
ehrlichiosis
Ehrlichia
chaffeensis
Lone star tick
(Amblyomma
americanum)
Ehrlichia
chaffeensis
Human
granulocytoropic
anaplasmosis
Anaplasma
phagocytophila
Deer tick
(Ixodes
scapularis
and Ixodes
pacificus)
Anaplasma
phagocytophila
Q fever
Coxiella
burnetti
Inhalation of
aerosol and
infected
animals
Coxiella
burnetti
Trench fever
Bartonella
quintana
Feces of body
louse
(Pediculus
humanus
corporis)
Bartonella
quintana
Cat scratch disease
Bartonella henselae
Kitten scratch or bite
Bartonella henselae
Bacillary
angiomatosis
Bartonella henselae
Oroya fever and
verruga peruana
Bartonella
bacilliformis
Sandfly
(Lutzomyia)
bite
Bartonella
bacilliformis
Categorized as a separate genus due to the
absence of lipopolysaccharide and
peptidoglycan and the presence of 54 to 58 kDa
major surface protein
ORIENTIA TSUTSUGAMUSHI
t replicates in the cytoplasm of its host cell and
is released through a process that involves
“pinching off” the host cell
ORIENTIA TSUTSUGAMUSHI
t replicates in the cytoplasm of its host cell and
is released through a process that involves
“pinching off” the host cell
MOA of ORIENTIA TSUTSUGAMUSHI
Leptotrombidum delicense (Chigger)
Vector of ORIENTIA TSUTSUGAMUSHI
Leptotrombidum delicense (Chigger)
Accidental hosts for ORIENTIA TSUTSUGAMUSHI
causes human
granulocytotropic
anaplasmosis
ANAPLASMA PHAGOCYTOPHILA
Ixodes pacificus
(Western black-legged
tick) and Ixodes scapularis (deer tick)
Vector of ANAPLASMA PHAGOCYTOPHILA
Peromyscus leucopus (white-footed
mouse)
Reservoir of ANAPLASMA PHAGOCYTOPHILA
The species of this genus are facultative,
intracellular and Gram-negative bacilli.
BARTONELLA
They live within the RBC in their natural
mammalian hosts
BARTONELLA
They live within the RBC in their natural
mammalian hosts
BARTONELLA
Some species exhibit a “twitching motility in wet
mounts
(B. bacilliformis and B. henselae)
Trench fever (louse-borne
disease)
B. quintana
Cat scratch disease
B. henselae
Infective endocarditis
B. elizabethae
Oroya fever (chronic
verruga peruana) and
febrile acute haemolytic
anemia
B. bacilliformis
Cat scratch disease
(secondary agent)
B. clarridgeiae
Causative agent of Q (Query) fever which is a
systematic infection of the lungs
COXIELLA BURNETTI
Not transmitted by arthropod vectors
COXIELLA BURNETTI
Can infect birds and rodents, which in turn
excrete the organisms via their urine, feces and
birth products
COXIELLA BURNETTI
Can survive extracellularly because of its
endospore-like body
COXIELLA BURNETTI
Extremely contagious and can be considered as
a potential bioterrorism agent
COXIELLA BURNETTI
inhalation of contaminated aerosols from
dried animal feces and ingestion of
contaminated unpasteurized milk
MOA of COXIELLA BURNETTI
Cattle, goats and sheep
Animal reservoir of COXIELLA BURNETTI
Species of the genus are Gram-negative
coccobacilli that undergo an intracellular
development cycle following the infection of
circulating WBC’s (replicate ion occurs in the
leukocytes)
EHRLICHIA
Presence of intravacuolar
microcolony that resembles “mulberries” or a
morula
MICROSCOPY OF EHRLICHIA
- Elementary body (infective form)
- Initial bodies
- Morulae
THREE DEVELOPMENTAL STAGES
Human and animals (dog and
deer)
Natural hosts of EHRLICHIA
Amblyomma americanum
Primary vector of EHRLICHIA
: E. chaffeensis and E. ewingii
Species of EHRLICHIA
Human monocytic ehrlichiosis
Infection of EHRLICHIA
- Immunohistology (Immunofluorescence and
immunoenzyme stains)
o Skin biopsy is utilized or usually used. - Giemsa stain
DIRECT METHODS
Yolk sacs of embryonated eggs
and tissue culture
Culture media for lab diagnosis of rickettsiaeae
isolated from human in an antibiotic-free,
centrifugation-enhanced shell vial cell culture
Rickettsia, Ehrlichia and Anaplasma
Columbia blood agar with 5% defibrinated blood
B. bacilliformis
preferred medium for
C. burnetti
Lung tissue cells
Only test preferred for diagnosis of rickettsial
disease.
SEROLOGICAL TEST
used to confirm rickettsiosis/ricketsioses
during convalescence stage.
SEROLOGICAL TEST
Antibodies to rickettsia can be detected until at
at
least 2 weeks after the infection.
seldom diagnosed serologically
during the acute stage of the illness due to the
absence of an early antibody response
Rickettsiosis
Gold standard serologic test or reference
method for rickettsioses and Q fever.
INDIRECT IMMUNOFLUORESCENT ANTIBODY
(IFA) ASSAY
Agglutination of certain strains of Proteus
vulgaris by serum from patient.
WEIL-FELIX REACTION
Presumptive test for rickettsioses
WEIL-FELIX REACTION
Individual with Q fever, ehrlichiosis and
rickettsial pox do not produce Weil-Felix
antibody
WEIL-FELIX REACTION
- Excellent for detecting antibodies to Rickettsia
- Used for early diagnosis of RMSF
MICROIMMUNOFLUORESCENT DOT TEST
can be performed through
PCR testing of lymph nodes.
Cat scratch disease
diagnostic tool for ehrlichiosis
PCR