Table 2. Clinical and environmental characteristics of reported TGR cases, Texas, 2003–2013*.
| Characteristic |
Total, no. (%) |
Confirmed case,† no. (%) |
Probable case,‡ no. (%) |
|---|---|---|---|
| Clinical features | |||
| Hospitalized | 1,047/1,758 (59.6) | 473/767 (61.7) | 574/991 (57.9) |
| Fever | 1,747/1,752 (99.7) | 759/764 (99.3) | 988/988 (100) |
| Headache | 1,353/1,753 (77.2) | 569/765 (74.4) | 784/988 (79.4) |
| Chills | 1,228/1,753 (70.1) | 511/765 (66.8) | 717/988 (72.6) |
| Malaise | 1,123/1,753 (64.1) | 471/765 (61.6) | 652/988 (66.0) |
| Anorexia | 925/1,753 (52.8) | 399/765 (52.2) | 526/988 (53.2) |
| Nausea/vomiting | 901/1,753 (51.4) | 381/765 (49.8) | 520/988 (52.6) |
| Myalgia | 890/1,753 (50.8) | 388/765 (50.7) | 502/988 (50.8) |
| Rash | 722/1,700 (42.5) | 325/747 (43.5) | 397/953 (41.7) |
| Diarrhea | 394/1,753 (22.5) | 184/765 (24.1) | 210/988 (21.3) |
| Photophobia | 381/1,752 (21.7) | 160/765 (20.9) | 221/987 (22.4) |
| Retroorbital pain | 266/1,753 (15.2) | 121/765 (15.8) | 145/988 (14.7) |
| Classical triad (fever, headache, rash) | 572/1,697 (33.7) | 240/745 (32.2) | 332/952 (34.9) |
| Abnormal laboratory findings | |||
| Elevated liver function | 478/1,751 (27.3) | 192/765 (25.1) | 286/986 (29.0) |
| Thrombocytopenia |
290/1,752 (16.6) |
123/765 (16.1) |
167/987 (16.9) |
| Environmental findings | |||
| Fleas present in home | 707/1,310 (54.0) | 313/580 (54.0) | 394/730 (54.0) |
| History of flea bite | 418/1,231 (34.0) | 187/538 (34.8) | 231/693 (33.3) |
| Rodents present | 379/1,312 (28.9) | 192/584 (32.9) | 187/728 (25.7) |
| Wildlife present | 587/1,383 (42.4) | 273/617 (44.2) | 314/764 (41.1) |
| Dogs present | 973/1,452 (67.0) | 411/640 (64.2) | 562/809 (69.5) |
| Cats present | 659/1,427 (46.2) | 298/633 (47.1) | 361/792 (45.6) |
| >1 species present | 844/1,463 (57.7) | 371/644 (57.6) | 472/816 (57.8) |
*Denominators are the number of case-patients for whom the information was available. CF, complement fixation; IFA, immunofluorescent antibody; IHA, indirect hemagglutination antibody; LA, latex agglutination; MA, microagglutination; TGR, typhus group rickettsiosis. †A confirmed case was defined as clinically compatible illness with 1) a >4-fold rise in antibody titer by IFA, CF, LA, MA, or IHA between acute and convalescent specimens; 2) a positive PCR result; 3) bacterial isolation from a clinical specimen; 4) positive immunofluorescence from tissue; or 5) a single IgM or IgG titer of >1,024 in a TGR-endemic region of south Texas (beginning in 2007) or Travis County (beginning in 2012). ‡A probable case was defined as clinically compatible illness and a single serologic titer of >128 by IFA, LA, MA, or IHA or a single titer >16 by CF.