Simulation of Rhipicephalus sanguineus control efficiency in residential environments using an individual-based model

The management of Rhipicephalus sanguineus s.l. (Latreille) residential infestations has long relied on the use of environmental and host-applied acaricides, such as permethrin, fipronil, and amitraz. For off-host environmental applications, the acaricides are used to target ticks in resting and developmental habitats, both indoors and outdoors. The available active ingredients used in topical formulations for on-host treatment, are few in number and utilize spot-on, shampoo, spray, and collars as delivery technologies. However, historical use of acaricides in the indoor environment and use of the same chemicals for prophylactic flea control on dogs has induced resistance in certain R. sanguineus s.l. populations against some common acaricides. Thus, some acaricides such as permethrin, often fail to eliminate a residential infestation. An individual-based model was used to evaluate the effectiveness of control strategies applied under different scenarios. Three control strategies were designed: on-host control only, off-host control only, and a combination of on- and off-host controls. For off-host control, tick resistance was considered by changing control efficiencies. The simulation results indicated that the control strategies that included on-host treatment were the most effective, where the infestation was eliminated shortly after the simulation started. However, the resistant tick population increased under off-host treatment only, which may be due to overcompensation, while the susceptible population was depressed but not eliminated. Thus, the results suggested that on-host treatment is the most effective control option for R. sanguineus s.l. residential infestations within the strategies evaluated.