Investigator(s)
| WHO Technical Officer |
Shahwar Kazmi WHO Country Office for India Shahwar Kazmi 
|
| Principal Investigator |
Manas Ranjan Dikhit Scientist C, ICMR-RMRIMS, Agamkuan, Patna-800007, India Manas Ranjan Dikhit
|
| Co-Investigator(s) |
Anil Kumar Scientist C, ICMR-RMRIMS, Agamkuan, Patna-800007, India Anil Kumar
|
Title(s) and abstract
| Scientific title | To Study The Genetic Profile And Insecticide Susceptibility Of P. Argentipes The Vector Of Visceral Leishmaniasis In The State Of Bihar, India |
| Public title | To Study The Genetic Profile And Insecticide Susceptibility Of P. Argentipes The Vector Of Visceral Leishmaniasis In The State Of Bihar, India |
| Background | Visceral leishmaniasis (VL) impacts 50,000–90,000 individuals annually across over 80 nations, with no available vaccines. The disease's treatment is primarily reliant on chemotherapy, which carries toxicity risks and the potential for drug resistance. Control efforts focus on managing Phlebotomus argentipes, the main vector in the Indian subcontinent, whose morphological variations, especially in antennal traits, influence vector competence. Research indicates shorter ascoids in populations from VL-endemic regions compared to non-endemic areas, suggesting different transmission roles. Effective control is hindered by morphospecies misidentification due to inadequate taxonomic distinctions. Insecticide susceptibility varies within P. argentipes; while susceptible to synthetic pyrethroids, it is resistant to DDT, with growing resistance to alphacypermethrin. Monitoring such variations is crucial for effective interventions. DNA barcoding, utilizing mitochondrial and ribosomal sequences like cox 1 and cyt b, aids in accurately characterizing sand flies. This genetic approach improves vector surveillance and informs strategic measures to control VL transmission. |
| Objectives | To explore the genetic profile of P. argentipes across various eco epidemiological settings in Bihar To understand the insecticidal susceptibility status among the species complex of P. argentipes in Bihar |
| Study Methods | The study focuses on visceral leishmaniasis (VL) prevalence, selecting three endemic and one non-endemic district, focusing on ecological variables like vegetation, water bodies, and insecticide exposure. In the endemic districts, nine villages are chosen to represent distinct ecotypes, aiming to understand how environmental conditions affect vector distribution and VL transmission. Sampling involves collecting sand flies from these areas using CDC light traps before the indoor residual spraying to minimize seasonal variations. Morphological identification is conducted using stereo microscopes, and specimens are preserved for DNA analysis. DNA extraction follows using commercial kits, focusing on the whole sand flies to ensure comprehensive results. PCR amplification of mitochondrial and ribosomal DNA markers (Cox1 and Cytb) are used to identify genetic variations, with analyses involving both positive and negative controls. Sequenced DNA undergoes electronic purification and submission to GenBank after confirmation. Insecticide susceptibility testing is performed on offspring sand flies, focusing on DDT and synthetic pyrethroids, following WHO protocols. Molecular methods assess the presence of resistance-related mutations. Sequence and phylogenetic analyses using ClustalW and MEGA software further elucidate genetic diversity and evolutionary relationships through haplotype and neutrality testing using software tools like dnaSP, Arlequin, and Network. The integrated approach aims to connect ecological, entomological, and genetic data to improve VL vector management, revealing intricate relationships influencing transmission dynamics and guiding effective interventions. |
| Expected outcomes and use of results | The expected outcomes of this study include the successful identification and characterization of P. argentipesand related species through molecular techniques. The analysis of DNA sequences will reveal distinct haplotypes, providing insights into the genetic diversity and phylogeographic patterns of these and flies in Bihar. The phylogenetic trees generated willclarify the evolutionary relationships within the P.argentipes complex. Triangulation of insecticidal susceptibility status with species complex inhabiting will give substantial evidences for residual transmission of VL in Bihar. Furthermore, the study anticipates identifying variations in genetic diversity indices, such as the Haplotype Diversity Index (Hd) and Nucleotide Diversity Index (Pi), as well as neutrality test results (Tajima’s D and Fu’s Fs), which will enhance understanding of population dynamics and historical demographics. Through analysis of molecular variance (AMOVA), the research will assess population structure and genetic differentiation. Additionally, median joining network analysis will elucidate the interrelationships between haplotypes, ultimately contributing valuable data for vector management strategies in visceral leishmaniasis control programs in endemic regions. |
| Keywords | Leishmaniasis, sandfly, Insecticide resistance |
Research Details
| Student research | No |
| Start Date | 17-Mar-2025 |
| End Date | 15-Dec-2025 |
| Key Implementing Institution | Rajendra Memorial Research Institute of Medical Science (ICMR Regional Institute) |
| Multi-country research | No |
| Nationwide research | No |
| India | |
| Research Domain(s) | Communicable Disease Research |
| Research field(s) | Infectious Disease |
| Involves human subjects | No |
| Data Collection | Primary data |
| Proposal reviewed by other Committee | No |