Rats and the COVID-19 pandemic: considering the influence of social distancing on a global commensal pest

Abstract

Rats contaminate foods and spread pathogens. Thus, changes in rat populations have consequences for society, especially in densely-populated cities. Following widespread social distancing and lockdown measures to curtail SARS-CoV-2, worldwide media outlets reported increased sightings of rats. To document possible changes in rat populations, we: (i) examined public service requests in the 6 years before, and during, ‘lockdown’ in New York City; (ii) used spatial analyses to identify calls in proximity to food service establishments (FSE); and (iii) surveyed pest-management companies. Over 6 years prior to the pandemic, we found a consistent moderate spatial association (r = 0.35) between FSE and rat-related calls. During the early stages of the pandemic, the association between rat reports and food services did not decrease as would be expected by restaurant closures, but instead modestly increased (r = 0.45). There was a 29.5% decrease in rat reports, overall. However, hotspot analysis showed that new reports were highly localized, yet absent in several industrial areas they were previously observed in, potentially masking a higher proportion of calls in neighborhoods near closed restaurants. Additionally, 37% of pest management companies surveyed reported that, unlike previous years, 50–100% of requests were from new clients and addresses. The finding that hotspots remained nearby dense clusters of restaurants does not support the common narrative that rats moved long distances. Rather, our results are consistent with rats finding nearby alternative food resources. Tracking these dynamics as the COVID-19 pandemic abates will be an important step to identifying how rats respond to society returning to normal activity patterns.

Association between anthropization and rodent reservoirs of zoonotic pathogens in Northwestern Mexico

“…Landfills have been proven to unintentionally provide food for generalist and synanthropic species that can be excellent reservoirs of zoonotic pathogens PLOS ONE [91], which may explain the case of M. musculus in SON. Consistently, two studies have found an increase in the movement and abundance of commensal rodents following the onset of the COVID-19 lockdown in New York [92] and Sydney [93]. These changes may potentially promote the spread of pathogens transmitted by M. musculus, R. rattus, and other invasive rodents.…”

“…musculus in SON. Consistently, two studies have found an increase in the movement and abundance of commensal rodents following the onset of the COVID-19 lockdown in New York [ 92 ] and Sydney [ 93 ]. These changes may potentially promote the spread of pathogens transmitted by M .…”

A Theory of City Biogeography and the Origin of Urban Species

“…A temporary version of such a scenario was mimicked during the early days of the pandemic when major cities were quarantined, restaurants were closed down and patterns of food waste availability were dramatically altered. During this interval, rat populations appear to have needed to seek out alternate food sources and moved from commercial to residential areas (Parsons et al, 2021). In an urban future in which waste is greatly reduced, one wonders, would rats and pigeons still persist in cities?…”

Urban Pest Abundance and Public Enquiries in Zurich 1991–2022

“…COVID-19 was present in Switzerland from early 2020 and from late February 2020 public gatherings were increasingly restricted, leading to a dramatic shift in the places where people spent their time. The pandemic appears to have made some pests, such as Rodentia, Zygentoma, S. paniceum and Columbidae more apparent, as a part of the changing observations of urban fauna [19,[30][31][32]. The year 2020 saw the largest ever number of records (2369) in the UPAS database, compared with the year before (2019: 2267) and after (2021: 1922).…”