Recalibration of insecticide-measuring containers could prevent underdosing of insecticide during indoor residual spraying for visceral leishmaniasis (kala-azar) elimination in India.

BACKGROUND

The visceral leishmaniasis (kala-azar) elimination programme in India relies on indoor residual spraying (IRS) for sand-fly vector control. Insecticide supplied by a new manufacturer was introduced for IRS in 2019. We aimed to explore whether this led to a change in insecticide quantity being used in the field.

METHODS

We compared measurements of weights of 250 mL of insecticide powder of two different manufacturers using a certified and calibrated weighing instrument.

RESULTS

The density of insecticide supplied in 2019 was 43.4% lower than that in 2018, thereby leading to underdosing during current IRS activity.

CONCLUSIONS

Insecticide-measuring containers should be recalibrated prior to every IRS round and also when an insecticide manufacturer changes, so that the insecticide dose is maintained within the recommended range.