The epidemiology and clinical features of rickettsial diseases in North Queensland, Australia: implications for patient identification and management

Stewart, Alexandra G.A., Smith, Simon, Binotto, Enzo, McBride, William J.H., and Hanson, Josh (2019) The epidemiology and clinical features of rickettsial diseases in North Queensland, Australia: implications for patient identification and management. PLoS Neglected Tropical Diseases, 13 (7). e0007583.

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Background: Rickettsial infections are a common cause of hospitalization in tropical settings, although early diagnosis is challenging in the rural locations where these infections are usually seen.

Methods: This retrospective, clinical audit of microbiologically-confirmed cases of scrub typhus or spotted fever group (SFG) rickettsial infection between 1997 and 2016 was performed a tertiary referral hospital in tropical Australia. Clinical, laboratory and radiological findings at presentation were correlated with the patients’ subsequent clinical course.

Results: There were 135 locally-acquired cases (95 scrub typhus, 37 SFG, 3 undifferentiated). There were nine hospitalizations during the first 5 years of the study period and 81 in the last 5 years (p for trend = 0.003). Eighteen (13%) of the 135 cases required ICU admission, all of whom were adults. A greater proportion of patients with SFG infection required ICU support (8/37 (22%) compared with 10/95 (11%) scrub typhus cases), although this difference did not reach statistical significance (p = 0.10). Three (8%) of the 37 patients with SFG infection had severe disease (1 died, 2 developed permanent disability) versus 0/95 scrub typhus patients (p = 0.02). Adults with a high admission qSOFA score (≥2) had an odds ratio (OR) of 19 (95% CI:4.8–74.5) for subsequent ICU admission (p<0.001); adults with a high NEWS2 score (≥7) had an OR of 14.3 (95% CI:4.5–45.32) for ICU admission (p<0.001). A patient’s respiratory rate at presentation had strong prognostic utility: if an adult had an admission respiratory rate <22 breaths/minute, the negative predictive value for subsequent ICU admission was 95% (95% CI 88–99).

Conclusions: In the well-resourced Australian health system outcomes are excellent, but the local burden of rickettsial disease appears to be increasing and the clinical phenotype of SFG infections may be more severe than previously believed. Simple, clinical assessment on admission has prognostic utility and may be used to guide management.

Item ID: 61780
Item Type: Article (Research - C1)
ISSN: 1935-2735
Copyright Information: © 2019 Stewart et al.
Date Deposited: 18 May 2020 23:43
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3207 Medical microbiology > 320701 Medical bacteriology @ 50%
42 HEALTH SCIENCES > 4202 Epidemiology > 420202 Disease surveillance @ 50%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 50%
92 HEALTH > 9204 Public Health (excl. Specific Population Health) > 920405 Environmental Health @ 50%
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