General introduction
Gram-negative, obligate intracellular
coccobacilli bacteria that infect mammaols and arthropods
Rickettsiae are transmitted in the
arthropods,which serves as both vector and reservior
Both DNA and RNA
Category of rickettsia
Genus
Rickettsia, Coxiella ,Orientia,Ehrlichia Bartonella
Species
Rickettsia prowazekii (epidemic typhus),
Rickettsia typhi (endemic typhus), Rickettsia rickettsii (spotted fever), Rochalimaea quintana
Bilogical features
Variable shape, coccobacilli Gram negative
Microcapsule and slim layer Culture : in york sacs of
Antigenic structure
LPS
Rickettsia tsutsugamushi Coxiella burnetii (Q fever) LPS smoothⅠ
LPS roughⅡ
Weil-Felix reacrion
Transmission
Typhus, spotted fever and trench fever are transmitted via arthropod vectors;
Q fever is acquired via inhalation or
Pathogenesis
Virulence factors: endotoxin,
phospholipase A, and slime layer
Sites: vascular system producing
vasculitis 血管炎
Characteristic triad of symptoms: fever,
Rickettsia prowazekii
普氏立克次体
epidemic typhus
average incubation periods (days):8 the louse
Respiratory tract and conjunctiva Latent period: 2 weeks
Abrupt onset,fever,chills,headache,
Rickettsia typhi
地方性斑疹伤寒立克次体
endemic typhus 7-14 days
Mice
the louse&flea
Mouth,nose and conjunctiva
Gradual onset,fever,headache,myalgia,
Rickettsia tsutsugamushi
恙虫病立克次体
Tsutsugamushi disease(scrub typhus) Mice
tsutsugamushi
Coxiella burnetti
贝纳柯斯体
Q fever
Cow and sheep
tick
High resistance
abrupt onset
,fever,headache,chills,myalgia ,granulomatous hepatitis
chronic diaease with subacute onset
Bartonella henselae
汉赛巴通体
CSD (cat scratch disease)
Cat and dog
Conjunctiva inflammation and lymph node
Ehrlichia
埃里希体属
Ehrlichia chaffeensis: human
monocytotropic ehrlichiosis
Ehrlichia sennetsu : human granulocyto
Diagnosis
The use of immunofluorescent antibodies to examine a biopsy can be diagnostic.
The organism can be inoculated into tissue
culture and grown over 4-7 days but this is very
hazardous to personnel.
The Weil-Felix test looks for the production of
Control
Sanitary: Arthropod and rodent control Immunological: No vaccines are
currently available.
