Unravelling a new focus of Spotted Fever Rickettsioses as causative agents of acute undifferentiated febrile illness in Odisha, A state in eastern Costal India

Dr Cs Premnath; Shriya Goel; Prof Bijayini Behera; Prof Manisha Biswal; Prof Baijayantimala Mishra; Prof Rashmi Ranjan Mohanty; Prof Rashmi Ranjan Das

doi:10.1016/j.actatropica.2025.107522

Unravelling a new focus of Spotted Fever Rickettsioses as causative agents of acute undifferentiated febrile illness in Odisha, A state in eastern Costal India

Acta Trop. 2025 Jan 4:107522. doi: 10.1016/j.actatropica.2025.107522. Online ahead of print.

Authors

Dr Cs Premnath¹, Shriya Goel², Prof Bijayini Behera³, Prof Manisha Biswal⁴, Prof Baijayantimala Mishra⁵, Prof Rashmi Ranjan Mohanty⁶, Prof Rashmi Ranjan Das⁷

Affiliations

¹ Department of Microbiology, AIIMS BHUBANESWAR. Electronic address: challaprenat@gmail.com.
² Department of Medical Microbiology, PGIMER, Chandigarh. Electronic address: shriyasood2@gmail.com.
³ Professor, Department of Microbiology, All India Institute of Medical Sciences [AIIMS], Bhubaneswar, Odisha.751019. Electronic address: drbinny2004@gmail.com.
⁴ Department of Medical Microbiology, PGIMER, Chandigarh. Electronic address: Manisha.biswal@gmail.com.
⁵ Professor & HOD, Department of Microbiology, All India Institute of Medical Sciences [AIIMS], Bhubaneswar, Odisha.751019. Electronic address: bm_mishra@hotmail.com.
⁶ Professor, Department of General Medicine, All India Institute of Medical Sciences [AIIMS], Bhubaneswar, Odisha.751019. Electronic address: genmed_rashmi@aiimsbhubaneswar.edu.in.
⁷ Professor, Department of Paediatrics, All India Institute of Medical Sciences [AIIMS], Bhubaneswar, Odisha.751019. Electronic address: rrdas05@gmail.com.

PMID: 39761867
DOI: 10.1016/j.actatropica.2025.107522

Abstract

Spotted fever group Rickettsia (SFGR) infections remain largely under-investigated as causative agents of acute undifferentiated febrile illness (AUFI) in resource-limited settings. Few studies are available on the prevalence of SFGR infections in India, especially in eastern India. In a cross-sectional study conducted in 192 hospitalized adult and paediatric patients with AUFI, the frequency of SFGR using sequential PCR targeting genes encoding citrate synthase gene (gltA), 17 kDa lipoprotein precursor antigen (17kDa), outer membrane proteins A and B (omp A & omp B) was 6.2% (12/192) including 7.4% (8/108) in adults and 4.7% (4/84) in paediatric patients with AUFI. Phylogenetic analysis of SFGR based on the concatenated sequences of omp A-gltA-17kDa-omp B showed that the patients' isolates obtained in the study clustered with Rickettsia conorii str. Malish 7 (AE006914.1). The SFGR cases described here, to the best of our knowledge, are the first human cases diagnosed in Odisha, eastern coastal India that were laboratory-confirmed by molecular detection and sequencing. The findings of this study will be beneficial for designing systematic future studies covering more geographical locations for continued surveillance of SFGR human infections along with vector surveillance.

Keywords: Rickettsia conori; Spotted Fever Rickettsia; acute undifferentiated febrile illness; sequential PCR.