Field-Based Assessment of Lymphatic Filariasis Transmission Dynamics and Intervention Outcomes in Varanasi District

Background-Lymphatic filariasis is a neglected tropical disease that imposes a significant burden on the mental, physical, and socioeconomic health of millions of people worldwide. India bears a considerable amount of this burden, with LF endemic in 21 states and union territories. The government of India implemented nationwide Mass Drug Administration and Triple Drug Therapy in a few districts, including Varanasi, as a part of the Global Programme to Eliminate Lymphatic Filariasis (GPELF).

Objective: This study intends to assess the IDA coverage in Varanasi from 2019 to 2021 and its effect on LF transmission with the help of night blood tests in different sentinels and spot check sites and to check the microfilariae rate (<1%) with the conduction of TAS in 2022.

Method: In this conducted study regions from both urban and rural consisting of various PHC/CHC in Varanasi district were selected for the MDA/IDA, data were collected annually, Night blood tests were performed following WHO protocols. Microfilariae rates were calculated in the areas and TAS were performed in sentinels and spot check sites to access the ongoing transmission.

Result: The coverage of IDA has significantly improved from 74.79% in 2019 to over 80% in 2020 and 2021. There was a decrease in microfilariae rate observed in sentinel sites, which was 0.94% in 2019 to 0.15% in 2021. Similarly, MF rates declined when checked in sentinel sites, from 0.46% in 2019 to 0.10% in 2021. TAS 2022, which involved 19,852 participants, showed an overall MF rate of 0.1% in most regions. However, Cholapur failed the TAS with a reported MF rate of 1.34%, which has led to more IDA rounds to follow.

Conclusion: This paper highlights the efficacy of IDA in reducing the LF transmission in Varanasi. There were areas that demonstrated substantial progress, while targeted efforts are still required in high-prevalence regions. Ongoing surveillance and strategic intervention are still required to achieve and sustain LF elimination goals till 2027.