The sandfly commonly shelters in cracks in poorly plastered mud houses, anthills and soil fissures, multiplying during the rainy season after prolonged drought.
The case is being called a bellwether proceeding because its outcome could set the tone for a tidal wave of similar litigation across the United States.
The dispute erupted into several rounds of clashes last year, killing dozens of people, including soldiers and civilians, and displacing more than a million in July and December.