Socioeconomic and environmental risk factors for urban rodent infestation in Sao Paulo, Brazil

Abstract

This article provides analyses of data on the premises infestation by commensal rodents collected during the 2006 Urban Rodent Survey, in Sao Paulo city, Brazil. A two-stage cluster sample survey was used to visit 23,512 premises, and logistic regression models were estimated in order to understand the relationships among the risk factors and the infestation probability. The premises infestation rates were 23.1% for all rodents, 12.7% for roof rat, 9.4% for Norway rat and 1.7% for house mouse. Factors found to be related to infestation levels were: socioeconomic conditions (human development index and income), premises features (commercial, strictly residential and vacant lots), and environmental resources (access, harborage and food). The analysis of odds ratios showed that access by the building structure favours roof rat and access by the sewage system favours Norway rat. Harborage in ceiling cracks are determinant for roof rat, harborage in wall cracks and in dense bush for Norway rat, and harborage in waste or in building material for house mouse infestations. Available animal food favour all the three species, fruit trees favour Norway and roof rats, human food is important for house mouse: therefore a natural partition of the environmental resources among the species was observed. The results obtained in this article add some knowledge on the biology and behaviour of commensal rodents.

Commensal Rodents in the City of Buenos Aires: A Temporal, Spatial, and Environmental Analysis at the Whole City Level

“…Within the city, shantytowns should be a priority for the design and implementation of control programs because they are the ones that showed the greatest abundance of rodents, and therefore, this environmental characteristic explains much of the differences in the abundance of rodents at the whole city scale. This agrees with the general idea that precarious conditions are favorable for commensal rodents (i.e., Childs et al 1998;Lambropoulos et al 1999;Langton et al 2001;Traweger et al 2006;Masi et al 2010). These shantytowns are dominated by R. norvegicus and M. musculus (Fernández et al 2007;Cavia et al 2009) and are environments that can be found only in South America, so it is not possible to easily adapt control programs developed elsewhere in the world.…”

“…This is consistent with that observed in this study, as surveys were performed where respondents primarily made reference to sightings of rats (Cavia and Muschetto, personal observations). In this matrix, sites with high concentration of buildings represent less favorable environments for these rodents as was also reported in England and São Paulo (Langton et al 2001;Masi et al 2010). These environments show a limited availability of open spaces (such as courtyards, gardens, etc.)…”

“…These studies include those carried out in New York (Childs et al 1998), São Paulo (Masi et al 2010), Budapest (Bajomi 1993), and cities all over England (Langton et al 2001). This lack of studies is probably due to difficulties in assessing the abundance of rodents at a city scale using traditional methods such as rodent traps (Cavia et al 2012).…”

“…None of the above studies used traps to estimate rodent abundance, and none of those studies could be easily replicated in many other cities. For example, Childs et al (1998) used records of rodent bites recorded at hospitals, information that is not frequently available in other cities, whereas Langton et al (2001), Masi et al (2010) and Bajomi (1993) used expensive methodologies in terms of personnel involved and time invested. For the reasons above, the development of easy-to-apply and low-cost alternative tools to assess rodent infestation levels would help both to systematically monitor their population fluctuations and to identify ''priority areas'' for the implementation of control programs.…”

Seasonal variation in population characteristics and management implications for brown rats (Rattus norvegicus) within their native range in Harbin, China

“…However, as commensal pests, brown rats are often blamed for huge damage in agricultural and urban areas, as well as for the transmission of a long list of diseases (Huang et al 1995;MacDonald et al 1999;Patergnani et al 2010;Traweger et al 2006). Regarding improvements in rodent control, most studies have focused on brown rats in urban areas (Castillo et al 2003;Traweger et al 2006;Masi et al 2010) and farms (Gómez Villafañe and Bush 2007;Villa et al 1997). Moreover, most of our understanding of this species is based on studies of populations outside their native range, such as in Europe and America (reviewed in MacDonald et al 1999;McGuire et al 2006).…”