Socioeconomic factors may be a driving force behind the emergence and spread of animal-borne disease outbreaks, according to new research from the University of Georgia and Oklahoma State University.
The study found that outbreaks of bacterial diseases, such as tuberculosis, plague and salmonella, were caused by things like poverty, international travel and poor access to health care, among others.
Meanwhile, environmental factors like changing weather patterns, natural disasters, close contact with livestock or wildlife can spark viral disease outbreaks. But it is often socioeconomic factors that help these diseases spread widely.
"It's important to think about what conditions we are creating that might lead to disease outbreaks in the future," said Payton Phillips, lead author of the study and a postdoctoral researcher at UGA's Savannah River Ecology Laboratory. "It's our behavior, our medical systems, our travel, our economic conditions that play a role in disease outbreaks.
"Knowing that these factors are so important, we need to push for better sanitation, improved water quality and more funding for medical interventions to keep outbreaks under control."
Socioeconomic, environmental factors key to stopping disease outbreaks
The researchers analyzed data from more than 300 global disease outbreaks, including the 100 largest outbreaks between 1977 and 2017. The scientists examined 48 different drivers of disease outbreaks, divided into socioeconomic or environmental categories.
Some of the socioeconomic factors included antibiotic use, contaminated water and food, sewage management and public health infrastructure. Environmental factors included climate change; the spread of disease vectors, such as mosquitoes; and the introduction of invasive species, among others.
"If we know there are socioeconomic issues, like if water sanitation is a problem for a local area, then we can try to address it ahead of an outbreak," Phillips said. "We can and should be more proactive."
Emerging diseases frequently come from animals
More than six out of every 10 infectious diseases in people originate in animal populations, according to the Centers for Disease Control and Prevention. And 75% of emerging diseases come from animals.
People originally become infected with these diseases through interactions with animals. This can happen directly, such as touching a sick animal or being bitten by one, or indirectly by consuming contaminated water or food, like raw milk or undercooked meat.
"Many viruses are naturally found in certain animals," Phillips said. "But it's our behavior that allows them to spread."
For example, scientists believe the viruses that cause Ebola originated in bats. Once an Ebola outbreak spills over into humans, the disease begins rapidly spreading from person to person.
Not every disease is capable of human-to-human spread. Avian influenza, for instance, appears to not easily spread from one infected person to another. But as more species are infected with a virus or bacteria, the threat of evolution - and the ability to spread between people - rises.
Published in Microorganisms, the study was co-authored by Sneha Dharwadkar, a doctoral student in the UGA College of Veterinary Medicine, and Mekala Sundaram, an assistant professor in the Department of Infectious Diseases and the Savannah River Ecology Laboratory. Additional co-authors include Oklahoma State University's Negin Nazari, Antoine Filion, Benedicta Akaribo and Patrick Stephens.
