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Volume 23, Number 12—December 2017
CME ACTIVITY - Dispatch

Newly Recognized Pediatric Cases of Typhus Group Rickettsiosis, Houston, Texas, USA

Timothy Erickson, Juliana da Silva, Melissa S. Nolan, Lucila Marquez, Flor M. Munoz, and Kristy O. MurrayComments to Author 
Author affiliations: The University of Texas Health Science Center, Houston, Texas, USA (T. Erickson); Baylor College of Medicine and Texas Children’s Hospital, Houston (T. Erickson, J. da Silva, M.S. Nolan, L. Marquez, F.M. Munoz, K.O. Murray)

Main Article

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.

Main Article

Page created: November 16, 2017
Page updated: November 16, 2017
Page reviewed: November 16, 2017
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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