Research & Analysis

New Study Links Biological Invasions With Zoonotic Disease Outbreaks

GIDEON is currently the most comprehensive and frequently updated infectious disease outbreak database reporting epidemics of human infectious diseases at the global scale and has been widely used in global zoonosis studies.

L. Zhang et al.

Introducing new species of animals to new surroundings can significantly increase the risk of zoonotic transmission – as many as 5.9 diseases per alien zoonotic host, as a 2022 study by Zhang et al. found. The authors feel that this number may be a conservative estimate because of the under-reporting of zoonotic events [1].

The study is the first to evaluate the role of multiple host and parasite taxa across the globe: 795 established alien hosts. The authors conducted an extensive analysis of all recorded zoonotic outbreaks in the world – since 1348 – using the comprehensive GIDEON database of infectious diseases.

The study also identified a spatial and temporal relationship between the increase in zoonosis events and the richness of alien zoonotic hosts.

Why is Research on Zoonoses Important?


60% of infectious diseases in humans and 75% of all emerging diseases are zoonotic [2]. Zoonotic diseases are diseases transmitted to a human from an animal or insect. Some diseases may result in mild symptoms, but others may lead to longer-term illness and death.

Zoonoses are responsible for almost one billion disease cases and millions of deaths each year [3]. COVID-19 caused 500 million reported cases and 6.2 million reported deaths in less than three years [4]. Other well-known zoonotic diseases are bird flu, brucellosis, anthrax, COVID-19, dengue, ebola, Lyme disease, malaria, rabies, ringworm, and swine flu.

It has become crucial to track zoonoses because new pathogens can arise, and outbreaks can spread worldwide in the blink of an eye.


There may be many casualties and fatalities with these new diseases before effective diagnosis, treatment, and vaccines can be developed. With heavy globalization, cross-border animal trade, and climate change, there is an intense urgency for research on zoonotic diseases. So much so that in 2020, the United Nations released a report titled ‘Preventing the next pandemic: Zoonotic diseases and how to break the chain of transmission’ on July 6th, 2020 – World Zoonoses Day [2].

The report identifies seven human-mediated factors that are most likely to drive the emergence of zoonotic diseases. They are:

  • Greater global demand for animal protein
  • Industrialization of animal-source foods, agriculture, and animal husbandry
  • More exploitation of wildlife
  • Rapid urbanization, change in land use, and industries that strip an animal’s natural habitat
  • Globalization, travel, and transportation of animals across countries
  • Changes in the food supply, and
  • Climate change


The Zhang study, in particular, studies the growing impact of introducing alien hosts into new surroundings, and the new zoonotic diseases that emerge as a result.

Why Is There an Increase in Alien Animal Invasions or Biological Invasions?


When we hear the word plague, we often think of the infectious ‘Black Death,’ the scourge of the 14th century – a gruesome pandemic relegated to our history books. But from 2010 to 2015, there were more than 3,000 cases of plague reported in the Democratic Republic of Congo, Madagascar, and Peru [5]. These cases were associated with invasive rats. North American raccoons introduced in Europe caused West Nile virus cases. The Aedes mosquito, known to carry Dengue, Chikungunya, and more, has been spreading to geographical regions like Australia and Northern Europe that are not their natural habitat.

The Zhang study found that biological invasions increase the number of zoonosis events according to the richness of the alien hosts. In particular, the research indicated that mammals like Artiodactyla, Carnivora, and Rodentia, and birds like waterfowl, Galliformes, and Passeriformes are the main species that showed a significant connection across space and time.

The World Needs to Accelerate Research Efforts on Emerging Zoonotic Diseases


What is clear from the Zhang study, as well as the UN report, is that the number of emerging zoonotic diseases is on the rise. The reasons are multi-factorial and need more research on infectious disease prevention, detection, and treatment.

Like the authors of this study, over 200 research publications have used GIDEON for their research. You get 272,000+ clinical references for the A-Z of infectious diseases, access to over 88,000 surveys, data on 26,246 disease outbreaks, and 365 diseases across 235 countries. The database is updated daily, and there are 38,241 graphs to help researchers for faster analytics and deeper insights.



[1]L. Zhang et al., “Biological invasions facilitate zoonotic disease emergences,” Nat. Commun., vol. 13, no. 1, p. 1762, 2022.
[2]U. N. Environment, “Preventing the next pandemic – Zoonotic diseases and how to break the chain of transmission,UNEP – UN Environment Programme, 15-May-2020. [Online]
[3]About, “Zoonotic disease: emerging public health threats in the Region,World Health Organization – Regional Office for the Eastern Mediterranean. [Online].
[4]WHO Coronavirus (COVID-19) dashboard,” [Online].
[5]“Discover A New Way to do research or analysis,” GIDEON, 29-Jun-2021. [Online]
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