The major vehicle for the transmission of zoonotic infectious diseases is water
The most common transmission vehicle of large-scale zoonotic infectious diseases is contaminated water. This is the conclusion of an investigation carried out by the Center for the Ecology of Infectious Diseases (CEID) of the University of Georgia. Unusual weather patterns and variation in the number of disease vectors, such as mosquitoes and ticks, are the next two most important factors in zoonotic infectious outbreaks.
In a study published in the Royal Society journal Philosophical Transactions B, researchers analyzed more than 4,400 zoonotic infectious disease outbreaks, identifying the 100 largest in terms of the number of human cases, all of which infected thousands to hundreds of people.
From the full list, they also randomly selected 200 outbreaks to serve as "case controls," most of which included 43 or fewer cases. They then compared the characteristics of the large-scale and control outbreaks, particularly how the primary causes of infection and disease spread varied among them.
A pioneering study
Lead author Patrick Stephens explains that this research is one of the first peer-reviewed studies to quantify the variation in drivers of infectious disease outbreaks around the world.
"In the era of COVID-19, it is understandable that many people do not realize how many outbreaks of other infectious diseases are caused by complex and interrelated ecological and socioeconomic conditions," he commented. "We know that factors such as exposure to wild mammals, habitat disturbance, international trade and travel, and contact with contaminated food and water are important considerations. Our research was designed to understand what proportion of outbreaks various factors contributed to. To our knowledge, this study is the first to do so for a global sample of outbreaks of many diseases."
Stephens worked with CEID researchers Nicole Gottdenker of the School of Veterinary Medicine and John Drake, Annakate Schatz and John Paul Schmidt of the Odum School to compile a list of contemporary zoonotic infectious diseases documented in the peer-reviewed scientific literature. Thus, they identified and scored 48 drivers of specific infectious diseases related to control and large-scale outbreaks in the ecological, environmental and socioeconomic categories.
Water pollution is a key factor
Both large-scale and control outbreaks were associated with water contamination, which was the most common driver of large outbreaks and the second most common driver of small control outbreaks. Examples of these water-associated diseases are hepatitis E, typhoid fever, and shigellosis (dysentery).
However, the remaining vehicles differed. In addition to water contamination, large outbreaks were most often associated with unusual weather patterns, changes in the abundance of vectors (disease carriers such as mosquitoes or ticks), and wastewater management.
Large outbreaks were also much more likely to be caused by viral pathogens such as SARS coronavirus, influenza virus, and Japanese encephalitis virus than smaller outbreaks. Typical smaller outbreaks were associated with food contamination, local livestock production, and human-animal contact. Lastly, individual large outbreaks tended to be driven by a greater variety of factors than control outbreaks.
"There is still a lot of work to be done to understand how large-scale infectious disease outbreaks can be prevented and controlled," Stephens said. "It is estimated that two-thirds of future infectious disease outbreaks are likely to be caused by zoonotic pathogens, and the number of these diseases is growing worldwide. Our research is an extremely important first step in better understanding global variation in the causes of outbreaks."
Comments
Copyright © 2025 - All Rights Reserved
ISSN 2768-198X
List
Add
Please enter a comment