Toxic contact targets (TCTs) for controlling sand flies and reducing Leishmania in an oasis ecosystem

Abstract

This study aimed to assess the effectiveness of Toxic Cloth Target (TCT) units in controlling blood-seeking sand flies (Phlebotomus papatasi) and reducing infection rates of Leishmania in two isolated oases in the lower Jordan Valley, Israel. The treated oasis deployed TCT units from May to November 2011, while the untreated control oasis received no intervention. Sand fly populations were monitored using non-baited CDC traps and infection rates were determined by dissection. In 2012, no treatments were applied, but monitoring continued to observe population trends.
Within 2 weeks of deploying TCTs, sand fly populations at the treated oasis decreased significantly, while populations at the control oasis slightly increased. Over the remainder of 2011, treated oasis populations continued to decline despite reductions in TCT numbers and monitoring frequency, while control oasis populations rose above pre-treatment levels. Infection rates, initially 11.4% at the treated oasis and 6.6% at the control, dropped by 88.3% at the treated oasis after TCT application but increased by 21.7% at the control. During the next 5 months, only 1 of 764 sand flies from the treated oasis was infected, whereas the control infection rate was 7.7% . In 2012, treated oasis populations remained lower than those in the control, except during the final months of monitoring when control populations declined slightly below treated levels.
The findings demonstrated that TCT units effectively reduced sand fly populations and infection rates in isolated conditions. Further research is needed to evaluate their potential for broader applications in areas with widespread sand fly populations.