Morphometric and molecular identification of Hymenolepis diminuta in domestic rats (Rattus rattus) from urban slums in Northeastern Bangladesh: Implications for zoonotic transmission

Objectives

Limited data on Hymenolepis species in Bangladesh present a significant gap in understanding their epidemiology and zoonotic potential. This study aimed to detect the presence of Hymenolepis diminuta in domestic rats from urban slums in Sylhet, Bangladesh and assess associated public health risks.

Methods

From February to May 2024, 36 domestic rats were trapped in slum households, prioritizing high-exposure zones, such as kitchens and bedrooms, where human-rodent interactions are most frequent. Trapped rats were euthanized and examined for helminth infections. Cestodes were morphologically analyzed, and selected specimens underwent molecular sequencing. A structured questionnaire survey was also conducted in affected households to assess awareness and rat control practices.

Results

Helminth infections were observed in 23 (63.9 %) rats, with cestodes present in eight (22.2 %). A total of 11 cestode specimens were identified as H. diminuta based on morphological features (elongated body, unarmed scolex, spherical eggs) and confirmed by sequence similarity (internal transcribed spacer 1 region of ribosomal DNA) with GenBank references. Surveys revealed zero household awareness of zoonoses despite frequent rat-related losses. Rat control was inconsistent, elevating spillover risks.

Conclusions

This study confirms R. rattus as a reservoir for H. diminuta in urban Sylhet and highlights the urgent need for targeted public health interventions to reduce zoonotic transmission risks.