Evidence of Dengue and Chikungunya Virus Co-circulation in Field Collected Aedes Mosquito Populations across Delhi, India
Pooja Prasad
*
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Priya Singh
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Sunita Patel
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Ashna Bhasin
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Arti Bahl
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Shaukat Kamal
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Tanzin Dikid
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
Ranjan Das
National Centre for Disease Control, 22-Sham Nath Marg, Delhi-110054, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: Vector surveillance provides early warning of arboviral transmission prior to the outbreaks. Delhi the capital of India, experiences frequent Dengue and Chikungunya cases. The study aimed to determine the prevalence and distribution of Dengue and Chikungunya virus in Aedes mosquitoes collected across different areas of Delhi.
Study Design: Field & Lab based study on Aedes mosquito collected from different zones of MCD Delhi.
Place and Duration of Study: Centre for Medical Entomology and Vector Management, VAD Laboratory, National Centre for Disease Control, Delhi from May 2025 to October 2025
Methodology: Adult Aedes mosquitoes were collected from 54 localities across Delhi in collaboration with the Municipal Corporation of Delhi. Specimens from residential and peri-domestic sites, were morphologically identified, and pooled (≤10 mosquitoes per pool). Viral RNA was extracted using TRIzol followed by column purification. Detection of dengue virus (DENV) and chikungunya virus (CHIKV) was performed using Real-time RT-PCR targeting the C-prM and E1 genes, respectively. Samples with Ct ≤40 were considered positive. The minimum infection rate (MIR) was calculated per 1,000 mosquitoes. Sampling and screening were conducted weekly or fortnightly.
Results: A total of 133 mosquito pools were screened for dengue virus (DENV) and chikungunya virus (CHIKV) using real-time polymerase chain reaction (Real Time -qPCR). Positive mosquito pools were detected in multiple zones of Delhi. Out of total tested pool (133 Pools), 8.27 % were positive for DENV alone while 3.76% showed co-positivity for both DENV and CHIKV viruses.
Conclusion: This study provides entomological evidence of concurrent circulation of DENV and CHIKV in Aedes populations in Delhi. Detection of both viruses in mosquito pools indicates the potential risk of dual outbreak and possible trans-ovarian transmission and emphasizing the need for strengthened integrated vector surveillance for timely outbreak preparedness and control
Keywords: DENV, CHIKV, Aedes, mosquito pool, arbovirus co-circulation, vector surveillance