Volume 23, Number 12—December 2017
CME ACTIVITY - Dispatch
Newly Recognized Pediatric Cases of Typhus Group Rickettsiosis, Houston, Texas, USA
Table
Demographic, social, and clinical characteristics of pediatric typhus group rickettsiosis case-patients, Houston, TX, USA, 2008–2016*
| Characteristic | All cases, n = 36 | Confirmed cases, n = 18 | Probable cases, n = 13 | Suspected cases, n = 5 |
|---|---|---|---|---|
| Median age (range), y |
11 (2–23) |
9 (2–23) |
9 (4–17) |
16 (8–19) |
| Sex | ||||
| M | 18 (50) | 7 (39) | 7 (54) | 4 (80) |
| F |
18 (50) |
11 (61) |
6 (46) |
1 (20) |
| Race/ethnicity | ||||
| White | 19 (53) | 8 (44) | 9 (69) | 2 (40) |
| Hispanic | 15 (42) | 9 (50) | 4 (31) | 2 (40) |
| Other or unknown |
2(6) |
1 (6) |
0 |
1 (20) |
| Exposures | ||||
| Dogs | 17 (47) | 9 (50) | 8 (62) | 0 |
| Cats | 16 (44) | 8 (44) | 6 (46) | 2 (40) |
| Opossums | 2 (6) | 1 (6) | 0 | 1 (20) |
| Fleas |
8 (22) |
4 (22) |
3 (23) |
1 (20) |
| History of travel | ||||
| To endemic area of Texas | 4 (11) | 4 (22) | 0 | 0 |
| To endemic area outside United States | 2 (6) | 2 (11) | 0 | 0 |
| To area with no known Rickettsia typhi |
4 (11) |
3 (17) |
1 (8) |
0 |
| Signs and symptoms | ||||
| Fever | 35 (97) | 17 (94) | 13 (100) | 5 (100) |
| Rash | 26 (72) | 13 (72) | 10 (77) | 3 (60) |
| Headache | 14 (39) | 8 (44) | 3 (23) | 3 (60) |
| Malaise | 13 (36) | 8 (44) | 5 (39) | 2 (40) |
| Vomiting | 12 (33) | 7 (39) | 4 (31) | 1 (20) |
| Anorexia | 11 (31) | 7 (39) | 4 (31) | 0 |
| Classical triad† | 11 (31) | 5 (28) | 3 (23) | 3 (60) |
| Lymphadenopathy | 10 (28) | 4 (22) | 4 (31) | 2 (40) |
| Abdominal pain | 10 (28) | 5 (28) | 4 (31) | 1 (20) |
| Conjunctivitis |
9 (25) |
4 (22) |
4 (31) |
1 (20) |
| Clinical findings | ||||
| Hepatosplenomegaly | 6 (19) | 4 (22) | 2 (15) | 1 (20) |
| Altered mental status | 3 (8) | 3 (17) | 0 | 0 |
| Elevated aminotransaminases | ||||
| Aspartate aminotransaminase | 31 (86) | 16 (89) | 11 (85) | 4 (80) |
| Alanine aminotransaminase | 32 (89) | 17 (94) | 11 (85) | 4 (80) |
| Hypoalbuminemia | 11 (31) | 6 (33) | 3 (23) | 2 (40) |
| Thrombocytopenia |
22 (61) |
11 (61) |
9 (69) |
2 (40) |
| Median days hospitalized (range) |
5 (0–14) |
6 (1–14) |
5 (0–10) |
4 (0–5) |
| PICU admissions |
7 (19) |
5 (28) |
2 (15) |
0 |
| Median titer for R. typhi (range) | 1:1,024 (1:64–16,384) | 1:2,048 (1:1024–1:16,384) | 1:256 (1:128–1:512) | 1:64 (1:64) |
*Values are no. (%) except as indicated. A confirmed case was defined by one of the following: 1) immunofluorescent antibody (IFA) assay titer >1:1,024, and a titer for R. typhi >2-fold greater than that for R. rickettsii to rule out cross-reactivity; 2) PCR positive; or 3) >4-fold increase in titer between acute and convalescent specimens. A probable case was defined as 1) an IFA titer >1:128, and a titer for R. typhi >2-fold greater than R. rickettsii and 2) clinically compatible illness involving fever with rash. A suspected case was defined as 1) IFA titer >1:64 and negative titer for R. rickettsii and 2) clinically compatible illness.
†Symptoms were fever, headache, and rash.