Beyond Zoonosis: The Mental Health Impacts of Rat Exposure on Impoverished Urban Neighborhoods.

Author:Lam, Raymond
Position:SPECIAL REPORT - Report - Cover story


Society has a negative perception of rats (Rattus spp.). From a health perspective, they are the source of a number of zoonoses (diseases transmitted to people from animals) that have caused considerable human morbidity and mortality around the world (Himsworth, Parsons, Jardine, & Patrick, 2013). From a sociological perspective, rats have become symbolic of filth and destitution (Edelman, 2002).

Rats thrive in urban centers where human environments provide easy access to harborage (places where pests seek shelter) and food (Clinton, 1969). Aging infrastructure, poor sanitation, high population/housing density, and poverty have been consistently associated with urban rat infestations (Himsworth et al., 2013; Johnson, Bragdon, Olson, Merlino, & Bonaparte, 2016). Many of these conditions are characteristic of impoverished urban neighborhoods in developed countries (Bashir, 2002; Himsworth et al., 2013) and are beyond the control of individual residents, with control resting in the hands of municipalities or landlords. Residents of impoverished urban neighborhoods are often ill-equipped to deal with rat infestations because of low education and income, as well as fear of landlord reprisal (Bashir, 2002).

Although the majority of concerns regarding urban rat infestations are centered around the risk of disease transmission, the incidence of rat-associated illness in developed cities is relatively low (Battersby, Hirschhorn, & Amman, 2008; Battersby, Parsons, & Webster, 2002). In the absence of immediate and obvious public health threats, governmental bodies can become apathetic and/or reactive to rats and rat-related issues (McBride, 2013; Staley, 2014). The potential nonphysical consequences of living with rats, however, have been largely ignored.

This blindspot is problematic because current cultures of complacency regarding rat infestations could inadvertently be contributing to a growing incidence and prevalence of mental health issues among already vulnerable populations. A lack of recognition regarding the potential mental health impacts of living with rats can, in turn, create a burden on the healthcare system when the root cause of the problem can potentially be addressed more effectively and efficiently upstream.

Mental health has been a neglected problem in the field of environmental health (Gong, Palmer, Gallacher, Marsden, & Fone, 2016). To address this, the World Health Organization has launched the Comprehensive Mental Health Action Plan 2013-2020, with prevention and research as two of its main objectives (Saxena, Funk, & Chisholm, 2013). Given the ubiquity of rats in the urban environment, and the fact that rat infestations disproportionately affect populations that are already marginalized and disadvantaged, it is important to understand the full scope of potential rat-related health risk in terms of both physical and mental effects. The goal of this review is to synthesize the published literature regarding the potential mental health impacts of rat infestations on residents living in impoverished urban neighborhoods.


To conduct this study, we reviewed articles in the following databases: Medline, Embase, Web of Science, PubMed, PsycINFO, and Cinahl. We conducted word searches using a combination of keywords and Medical Subject Headings (MeSH) pertaining to three main concepts: rats (rats, rodents, rat infestation, rodent infestation, rodentia, Rattus norvegicus, Rattus rattus, black rat, Norway rat, brown rat), psychological effects (mental health, mental disorder, anxiety, stress, psychological stress), and impoverished urban populations (urban, poor, poverty, poverty areas, socioeconomic factors, slums, social class). The Boolean operators OR and AND were used to combine keywords/MeSH terms within and between concepts, respectively. Reference chaining and manual citation searching of reference lists were used to supplement results. Two reviewers, R. Lam and C. Himsworth, screened this step to ensure the search scope was refined to the research question.

We further limited the search scope to literature that discussed the impact of rat infestations (including as part of general rodent infestations) on mental/psychological health in residents of urban neighborhoods. We excluded literature focusing on the mental health impact of other pest species (e.g., mice), studies that did not pertain to urban centers (e.g., rural settings), and papers written in languages other than English. Additionally, R. Lam screened titles and abstracts to determine relevancy and then reviewed full text articles to determine if the inclusion criteria were met.


Our search yielded 756 articles, of which 8...

To continue reading