Volume 14, Number 5—May 2008
Fatal Rickettsia conorii subsp. israelensis Infection, Israel
|Day after disease onset||Assay||Specimen(s) tested||Result||Laboratory|
|11 (autopsy)||IFA||Serum||IgM = 64, IgG<32||CDC‡|
|PCR||Serum sediment Liver, muscle, skin, lung, kidney Liver, muscle, skin||Rickettsia conorii subsp. israelensis Spotted fever group rickettsiae R. conorii subsp. israelensis||CDC IIBR§ CDC¶|
|IHC stain#||Brain, kidney||Positive||CDC|
|Cell culture**||Liver, lung||Negative||IIBR|
*IFA, immunofluorescent assay; Ig, immunoglobulin; IIBR, Institute for Biological Research; CDC, Centers for Disease Control and Prevention; IHC, immunohistochemical.
†IFA performed (6). Cutoff values for IgM and IgG are 100.
‡IFA performed (7). Cutoff values for IgM and IgG are 64.
§Nested PCR for 17-kDa protein gene (8).
¶Nested and semi-nested PCR for 17 kDa protein gene and recombinant outer membrane protein A gene fragment, respectively, followed by sequencing (9).
#Three-micron sections cut from formalin-fixed, paraffin-embedded brain and kidney tissue samples were stained by using an immunoalkaline phosphatase technique with a hyperimmune rabbit anti–Rickettsia rickettsii antibody at a dilution of <500 (3).
**Homogenized samples from lung and liver were applied by centrifugation onto monolayer of Vero cells culture in 24-well plates and incubated for 2 weeks at 35°C in 5% CO2 atmosphere incubator.