Demographic Profile and Scrub Typhus IgM ELISA Positivity Among Suspected Cases in and Around Machilipatnam Over One Year: A Retrospective Cross-Sectional Study

Meesala Aparna; MHV Sindhura; M Anusha; A.Durga Rani

doi:10.51168/6zhxrm28

Authors

Dr. Meesala Aparna Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India.
Dr. MHV Sindhura Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India
Dr. M Anusha Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India
Dr. A.Durga Rani Professor and Head, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India

DOI:

https://doi.org/10.51168/6zhxrm28

Keywords:

Scrub typhus, Orientia tsutsugamushi, Immunoglobulin M enzyme-linked immunosorbent assay, acute febrile illness

Abstract

Background: Scrub typhus is an important cause of acute undifferentiated febrile illness in India and requires local surveillance because its clinical presentation overlaps with other tropical infections.

Objectives: To describe the demographic profile of suspected scrub typhus cases and estimate Scrub Typhus IgM ELISA positivity among patients tested in and around Machilipatnam.

Methods: This retrospective cross-sectional study was conducted at SPV Government Medical College, Machilipatnam, using de-identified laboratory records from 13 April 2025 to 13 May 2026. Suspected cases with serum samples tested for scrub typhus were included. Demographic details, OPD/IPD status, district, sub-district, test performed, result, and date of sample collection were analysed. IgM ELISA positivity was calculated among ELISA-tested cases.

Results: A total of 137 suspected cases were analysed. The mean age was 29.9 +/- 22.7 years and the median age was 26 years. Females constituted 70 cases (51.1%) and males 67 cases (48.9%). OPD cases were 67 (48.9%) and IPD cases were 70 (51.1%). IgM ELISA was performed in 133 cases, of which 48 were positive, giving an ELISA positivity of 36.1%. Positivity was highest in the 20-39-year age group and was concentrated during December 2025.

Conclusion: Scrub typhus IgM ELISA positivity was substantial among clinically suspected cases, supporting routine laboratory confirmation in febrile illness surveillance.

Recommendations: Strengthening early clinical suspicion, timely sample referral, and seasonal public health awareness can improve diagnosis and treatment initiation in the Machilipatnam region.

Author Biographies

Dr. Meesala Aparna, Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India.

is an Assistant Professor in the Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India. She is actively involved in undergraduate medical teaching, diagnostic microbiology services, infection control activities, and academic work. Her professional interests include bacteriology, antimicrobial susceptibility testing, hospital infection surveillance, and applied clinical microbiology. ORCID iD: https://orcid.org/0009-0006-0604-1155
Dr. MHV Sindhura, Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India

is an Assistant Professor in the Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India. She is engaged in medical education, laboratory-based diagnosis, and routine microbiological investigations. Her areas of interest include clinical bacteriology, antimicrobial resistance patterns, infection prevention, and microbiological quality practices.
Dr. M Anusha, Assistant Professor, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India

is an Assistant Professor in the Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India. She is involved in undergraduate teaching, diagnostic laboratory services, and academic activities in clinical microbiology. Her professional interests include infectious disease diagnostics, bacteriological culture methods, antimicrobial resistance, and public health microbiology.
Dr. A.Durga Rani, Professor and Head, Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India

is Professor and Head of the Department of Microbiology, Sri Pingali Venkaiah Government Medical College, Machilipatnam, Krishna District, Andhra Pradesh, India. She has extensive experience in medical teaching, diagnostic microbiology, laboratory administration, infection control, and academic supervision. Her areas of interest include clinical microbiology, antimicrobial resistance surveillance, hospital infection control, and mentoring undergraduate and postgraduate academic activities.

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