In the peri- and post-elimination settings, a strong kala-azar surveillance framework will be required to measure ongoing transmission and ensure outbreaks do not occur. Molecular xenomonitoring involves detecting pathogen DNA or RNA in vectors. It has been used successfully to assess elimination endpoints for lymphatic filariasis in several countries, but requires technical development for kala-azar.
Xenomonitoring for kala-azar requires a polymerase chain reaction assay to detect Leishmania donovani in Phlebotomus argentipes sandflies collected from areas where kala-azar transmission has been a concern. There are many advantage to this approach in that it is a less-invasive, ethically acceptable and potentially more cost-effective method of monitoring transmission in elimination settings than surveying human populations.
SPEAK India xenomonitoring studies commenced in June 2018 in Bihar and are a collaboration between researchers at the Rajendra Memorial Research Institute of Medical Sciences and the London School of Hygiene and Tropical Medicine. Main project objectives are to:
Subramanian et al. 2020. 'Molecular xenomonitoring as a post-MDA surveillance tool for global programme to eliminate lymphatic filariasis: Field validation in an evaluation unit in India'. PLoS NTD 14(1): e0007862.
Poché et al. 2018. 'Bionomics of Phlebotomies argentines in villages in Bihar, India with insights into efficacy of IRS-based control measures'. PLoS NTD 12(1): e0006168.
Subramanian et al. 2017. 'Application of a household-based molecular xenomonitoring strategy to evaluate the lymphatic filariasis elimination program in Tamil Nadu, India'. PLoS NTD 11(4): e0005519.
Cameron et al. 2016. 'Understanding the Transmission Dynamics of Leishmania Donovani to Provide Robust Evidence for Interventions to Eliminate Visceral Leishmaniasis in Bihar, India'. Parasites & Vectors 9:25.
Rao et al. 2016. ‘Programmatic use of molecular xenomonitoring at the level of evaluation units to assess persistence of lymphatic filariasis in Sri Lanka’. PLoS NTD 10(5): e0004722.
Lau et al. 2016. ‘Lymphatic filariasis elimination in American Samoa: evaluation of molecular xenomonitoring as a surveillance tool in the endgame’. PLoS NTD 10(11): e0005108.
Tiwary et al. 2012. 'Prevalence of sand flies and Leishmania donovani infection in a natural population of female Phlebotomus argentipes in Bihar State, India'. Vector Borne Zoonotic Diseases, 12(6): 467-472.
Prof Mary Cameron
Prof Susan Campino
Dr Miguella Mark-Carew
Dr Matthew Rogers
Dr Mojca Kristan
Ms Shannon McIntyre
Ms Giorgia Dalla Libera Marchiori
Dr Pradeep Das
Dr Vijay Kumar
Dr Vikram Pal Gandhi
Dr. Ashish Kumar