Human spotted fever group rickettsioses are underappreciated in southern Taiwan, particularly for the species closely-related to Rickettsia felis

Chung-Hsu Lai; Lin-Li Chang; Jiun-Nong Lin; Kun-Hsien Tsai; Ya-Chien Hung; Li-Li Kuo; Hsi-Hsun Lin; Yen-Hsu Chen

doi:10.1371/journal.pone.0095810

Human spotted fever group rickettsioses are underappreciated in southern Taiwan, particularly for the species closely-related to Rickettsia felis

PLoS One. 2014 Apr 22;9(4):e95810. doi: 10.1371/journal.pone.0095810. eCollection 2014.

Authors

Chung-Hsu Lai¹, Lin-Li Chang², Jiun-Nong Lin³, Kun-Hsien Tsai⁴, Ya-Chien Hung⁵, Li-Li Kuo⁶, Hsi-Hsun Lin⁷, Yen-Hsu Chen⁸

Affiliations

¹ Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan; Division of Infection Control Laboratory, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan.
² Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Faculty of Medicine, Department of Microbiology, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan.
³ Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan.
⁴ Institute of Environmental Health, College of Public, Health, National Taiwan University, Taipei City, Taiwan; Infectious Diseases Research and Education Center, Ministry of Health and Welfare and National Taiwan University, Taipei City, Taiwan.
⁵ Division of Infection Control Laboratory, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan.
⁶ Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Research and Diagnostic Center, Centers for Disease Control, Department of Health, Taipei City, Taiwan.
⁷ Division of Infectious Diseases, Department of Internal Medicine, E-Da Hospital/I-Shou University, Kaohsiung City, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei City, Taiwan.
⁸ Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan; Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan; School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan.

Abstract

Background: Despite increased identification of spotted fever group rickettsioses (SFGR) in animals and arthropods, human SFGR are poorly characterized in Taiwan.

Methods: Patients with suspected Q fever, scrub typhus, murine typhus, leptospirosis, and dengue fever from April 2004 to December 2009 were retrospectively investigated for SFGR antibodies (Abs). Sera were screened for Rickettsia rickettsii Abs by indirect immunofluorescence antibody assay (IFA), and those with positive results were further examined for Abs against R. rickettsii, R. typhi, R. felis, R. conorii, and R. japonica using micro-immunofluorescence (MIF) tests. Polymerase chain reaction (PCR) for detection of SFGR DNA was applied in those indicated acute infections. Case geographic distribution was made by the geographic information system software.

Results: A total of 413 cases with paired serum, including 90 cases of Q fever, 47 cases of scrub typhus, 12 cases of murine typhus, 6 cases of leptospirosis, 3 cases of dengue fever, and 255 cases of unknown febrile diseases were investigated. Using IFA tests, a total of 49 cases with 47 (11.4%) and 4 (1.0%) cases had sera potentially positive for R. rickettsii IgG and IgM, respectively. In the 49 cases screened from IFA, MIF tests revealed that there were 5 cases of acute infections (3 possible R. felis and 2 undetermined SFGR) and 13 cases of past infections (3 possible R. felis and 10 undetermined SFGR). None of the 5 cases of acute infection had detectable SFGR DNA in the blood specimen by PCR. Possible acute infection of R. felis was identified in both one case of Q fever and scrub typhus. The geographic distribution of SFGR cases is similar with that of scrub typhus.

Conclusions: Human SFGR exist and are neglected diseases in southern Taiwan, particularly for the species closely-related to R. felis.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Antibodies, Bacterial / blood
Antibodies, Bacterial / immunology
DNA, Bacterial
Female
Geography, Medical
Humans
Male
Middle Aged
Rickettsia / classification
Rickettsia Infections / diagnosis
Rickettsia Infections / epidemiology*
Rickettsia Infections / microbiology
Rickettsia felis* / classification
Rickettsiaceae Infections / diagnosis
Rickettsiaceae Infections / epidemiology*
Rickettsiaceae Infections / microbiology
Risk Factors
Serotyping
Taiwan / epidemiology

Substances

Antibodies, Bacterial
DNA, Bacterial

Grants and funding

This work was supported by research grants from the National Science Council [NSC 98-2745-B-650-001 and NSC100-2314-B-037-001-MY3] and E-Da Hospital [EDAHP98008]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.