MOVIMENTO, INFESTAÇÃO e MANEJO de Rattus norvegicus em FAVELAS URBANOS

Abstract

Synanthropic rats are worldwide invasive and prevalent pest in low-income urban environments; they are difficult to control and constitute a public health and agricultural threat to the human race. In low-income urban communities, rodent expansion and migration between households or neighbourhoods is a persistent problem, demanding control efforts. Therefore, advancing effective rodent control programs requires an in-depth understanding of their movement and behaviour (short and long-term) to chemical and sanitary/infrastructural intervention. Thus, this thesis is divided into three chapters, with each representing an article. The first chapter uses Rhodamine B (RB) a non-toxic dye to assess the distance travelled by rats within or areas around households in a slum environment in the city of Salvador (BA-Brazil); the second chapter examined the short-term outcome of chemical and sanitary interventions on rat sightings in seven low-income urban communities of New Providence, in the Bahamas; and the third chapter characterized the long-term outcome of chemical and infrastructural interventions on rat infestation level in three valleys of a low-income community of Salvador. In chapter one, we trapped rats to a maximum distance of 90m for four consecutive days and reported that rats do travel up to 90m distance even in a complex urban community. We also established that RB is a reliable alternative method that can be used to investigate the movement of small mammals even in urban settings. In chapter two, we systematically recorded rat sightings before and three months after interventions (rodenticide application & improvement of sanitation system), and observed a slight decrease in rat sightings after the intervention, although with varied effectiveness across the sampling locations. Lastly, in chapter three, we systematically recorded rat infestation before and three years after interventions (rodenticide applications and infrastructural). The study occurred in three valleys, with valleys 1 and 4 serving as the treatment valleys (received both types of interventions), while valley 2 served as the control (received no chemical intervention). We reported that the interventions substantially decreased rat infestations for 5-6 months, at the treatment valleys with a haphazard infestation level recorded at the control valley. Therefore, we concluded that Rhodamine B is a viable, cheaper and safer method for tracking rodent movement in urban settings, and also that, although chemical intervention alone offers a cheap and easy method of controlling rats, however, its overall effectiveness is short-lived. As a result, we advocate that a site-specific integrated approach system that incorporates both chemical and non-chemical methods of rodent control should be considered when planning rodent management programs to obtain an effective long-term result.