Volume 30, Number 7—July 2024
Research
Newly Recognized Spotted Fever Group Rickettsia as Cause of Severe Rocky Mountain Spotted Fever–Like Illness, Northern California, USA
Will S. Probert
, Monica P. Haw, Aran C. Nichol, Carol A. Glaser, Sarah Y. Park, Laura E. Campbell, Kavita K. Trivedi, Hannah Romo, Megan E.M. Saunders, Anne M. Kjemtrup, Kerry A. Padgett, and Jill K. Hacker
, Monica P. Haw, Aran C. Nichol, Carol A. Glaser, Sarah Y. Park, Laura E. Campbell, Kavita K. Trivedi, Hannah Romo, Megan E.M. Saunders, Anne M. Kjemtrup, Kerry A. Padgett, and Jill K. Hacker
Table 1
Clinical and laboratory features of Rickettsia sp. CA6269 infections in study of newly recognized SFG Rickettsia as cause of severe RMSF-like illness, northern California, USA*
| Feature | Case-patient 1 | Case-patient 2 |
|---|---|---|
| Clinical | ||
| Fever at hospital admission | Present, 103°F (39.4°C) | Present, 101.8°F (38.8°C) |
| Inoculation eschar | Absent | Absent |
| Rash | Absent | Present, maculopapular including palms |
| Myalgia | Present | Present |
| Headache | Present | Present |
| Nausea | Present | Present |
| Vomiting | Present | Present |
| Diarrhea | Present | Absent |
| Abdominal pain | Present | Absent |
| Acute kidney injury | Present | Absent |
| Photophobia | Present | Present |
| Altered mental status | Present | Present |
| Acute respiratory failure | Present | Present |
| Cutaneous necrosis and gangrene | Present | Absent |
| Coma | Present | Present |
| Days in intensive care unit | 11 | 4 |
| Days hospitalized |
22 |
13 |
| Laboratory† | ||
| Serum sodium | Low (124 mEq/L) | Low (133 mEq/L) |
| Serum lactate dehydrogenase | High (421 U/L) | High (1,280 U/L) |
| Serum creatinine | High (1.44 mg/dL) | Unremarkable (1.0 mg/dL) |
| Serum bilirubin, total | High (2.3 mg/dL) | Unremarkable (0.6 mg/dL) |
| Aspartate transaminase | High (483 U/L) | High (268 U/L) |
| Alanine transaminase | High (323 U/L) | High (125 U/L) |
| CBC platelets | Low (45K/uL) | Low (80K/uL) |
| CBC leukocyte count | Unremarkable (4.5K/uL) | High (12.9K/uL) |
| CBC neutrophil percentage | Unremarkable (64%) | High (84%) |
| CSF glucose | NA | Unremarkable (69 mg/uL) |
| CSF protein | NA | High (147 mg/dL) |
| CSF leukocyte count | NA | High (9/uL) |
| SFG Rickettsia IgG titer (acute) | Unremarkable <1:128 | Elevated (1:4,096) |
| SFG Rickettsia IgG titer (convalescent) | Elevated (>1:256) | Elevated (1:16,384) |
*CBC, complete blood count; CSF, cerebral spinal fluid; NA, not applicable; RMSF, Rocky Mountain spotted fever; SFG, spotted fever group. †Samples for the blood metabolic panel, CBC, and CSF analyses (case-patient 2 only) were collected on the day of hospital admission for case-patient 1 and 3 days after hospital admission for case-patient 2.
Page created: May 17, 2024
Page updated: June 22, 2024
Page reviewed: June 22, 2024
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