 Combined LLIN and IRS. In practice the IRS will not be applied alone but either with a conventional LLIN or LLIN with PBO synergist. An example of the potential impact of a conventional LLIN and P-methyl CS combination intervention was shown in an experimental hut trial in Burkina Faso 15. In this country with moderate pyrethroid resistance, the pyrethoid LLIN alone killed approximately 50 of the mosquitoes and reduced biting blood-feeding from 80 to 24. The P-methyl IRS alone killed 100 of mosquitoes but not before 40 had succeeded in blood feeding. It was the combination of LLIN and sprayed wall which had the largest impact, killing 100 of mosquitoes and preventing biting by 93, thus illustrating the potential benefit of the combination intervention. 