City Wildlife Like Rats Do Not Pose Much Threat to Future Pandemics, International Team of Researchers Says

Led by Georgetown University scientists, a team of international researchers recently found that urban pests may pose less of a threat to future public health pandemics than we believe.

For too long many believe that rats and the like are one-of-a-kind disease reservoirs that rampantly spread bacteria and diseases. They are believed to be the triggers of future public health pandemics. However, the team disagrees.

Understanding the Risks Posed by Urban Pests in Pandemics

In a recent study published in the journal Nature Ecology and Evolution, titled "Urban-adapted mammal species have more known pathogens" researchers aimed to understand whether animals that have adapted to dwelling and thriving in cities tended to have different viruses. The study was led by a postdoctoral fellow in the University of Georgetown's Department of Biology, Greg Albery, Ph.D.

The ongoing COVID-19 pandemic has sparked renewed interest in where future pandemics and outbreaks are at the highest risk of emerging. Experts have long suspected that hotspots for outbreak risks are in cities, mostly thanks to species of urban wildlife, like rats, that have made their homes alongside humans. For those in Washington, D.C., these problems are now closer to home.

This March, the US Centers for Disease Control and Prevention announced that the increasing rat problem has enabled a respiratory virus known as Seoul hantavirus to infect two people back in 2018.

Albery and the team set out to study whether urban pests play host to a greater variety of pathogens. In a recent study, the team analyzed the pathogens hosted by roughly 3,000 mammalian species and found that animals that have adapted in the urban setting could host about ten times as many different diseases. However, the team also found that pattern was a problem brought about by sampling bias.

Albery explains that there are numerous reasons to expect urban pests to host more diseases, ranging from their diet to their immune system to their close proximity to us. He adds that the team found that these urban species do indeed host more diseases than their non-urban counterparts. The team carefully analyzed the animals in cities more, hence they were able to find more parasites.

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Adjusting Sampling Biases

After the team adjusted to take into account the sampling bias, they found that city-dwelling species don't seem to host more human-infective viruses than their rural counterparts. He explains that stunningly, although these urban pests have 10 more parasites when taking sampling bias into consideration they do not have more human pathogens than scientists previously expected, reports EurekAert.

This means that our perception of city wildlife's novel disease risks has been overinflated by the repetitive sampling.

The recent study may be able to exonerate urban pests from being viewed as hyper-reservoirs of infectious diseases. On the other hand, Albery cautions the public that the findings do not equate that cities are disease-free. Stating that the study only suggests that urban pests do not harbor as many novel pathogens as experts have believed.