MAR 18, 2015 7:19 AM PDT

Emerging Diseases Likely to be More Harmful in Similar Species

WRITTEN BY: Judy O'Rourke
When viruses such as influenza and Ebola jump from one species to another, their ability to cause harm can change dramatically, but research from the University of Cambridge shows that it may be possible to predict the virus's virulence by looking at how deadly it is in closely-related species.

A number of emerging infectious diseases - including some of the most deadly outbreaks such as Ebola, SARS, and HIV - are the result of humans becoming infected with a pathogen that normally infects another species. The amount of harm caused by a pathogen when it jumps into a new species can be very variable, at times causing few, if any symptoms, while at other times causing high levels of mortality.

A team led by researchers at the Department of Genetics, University of Cambridge, has looked at how the harm a pathogen causes can change following a jump between species. The researchers infected 48 species of fruit fly with an RNA virus, and found that the amount of harm caused by the virus was extremely variable in the new hosts, with some species having relatively benign infections and other species dying rapidly. Most of the deadly emerging diseases that infect humans are caused by RNA viruses.

The different species of fruit fly shared a common ancestor around 40 million years ago. The relationships between the different species can be examined using an evolutionary ‘tree' known as a phylogeny. Species that cluster together are the most genetically similar.

In a study recently published in the journal PLOS Pathogens, the researchers show that closely related species show similar levels of virulence when infected with the virus, with the tree of species being a patchwork of closely related groups showing high or low virulence. The level of virulence observed appears to be due to the amount of virus that accumulates in the hosts. The viral load also likely affects the ability of the virus to spread.

Although the research was carried out in fruit flies, the researchers suggest that the general principle should be applicable across species. A study published in the journal Science in 2014 showed a pattern consistent with such effects in amphibians infected by chytrid fungus.

"We see such patterns in the wild," says Ben Longdon, PhD. "The Ebola virus, for example, appears to cause few symptoms in its natural reservoir, the fruit bat, but it is deadly in chimpanzees, gorillas, and humans.

"While there may be no clear rule to predict how deadly a pathogen will be in a new host, a simple rule of thumb may be that if it causes high levels of virulence in any given host species, it will typically cause similar levels of virulence in closely-related hosts," he adds. "If we see a new disease emerge that causes high levels of mortality in chimpanzees, for example, then it may also be a danger to humans."

[Source: University of Cambridge]
About the Author
  • Judy O'Rourke worked as a newspaper reporter before becoming chief editor of Clinical Lab Products magazine. As a freelance writer today, she is interested in finding the story behind the latest developments in medicine and science, and in learning what lies ahead.
You May Also Like
SEP 13, 2020
Genetics & Genomics
Men and Women Express Many Genes at Different Levels
SEP 13, 2020
Men and Women Express Many Genes at Different Levels
Most humans carry the same genes in their genome, but how are genes expressed differently in men and women?
SEP 17, 2020
Genetics & Genomics
Revealing More About the Past With a New Metagenomic Technique
SEP 17, 2020
Revealing More About the Past With a New Metagenomic Technique
Scientists can use advanced genomics techniques to mine samples for all the genetic material they contain.
OCT 01, 2020
Microbiology
Investigating the Origins of a Cholera Epidemic
OCT 01, 2020
Investigating the Origins of a Cholera Epidemic
Cholera is an intestinal infection caused by Vibrio cholerae. Cholera has been a scourge throughout human history, and i ...
OCT 03, 2020
Cell & Molecular Biology
Growing an Organism From One Cell
OCT 03, 2020
Growing an Organism From One Cell
Scientists have used model organisms to view the first few hours of development in various organisms. A single cell is f ...
OCT 18, 2020
Genetics & Genomics
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
OCT 18, 2020
'Silent' Mutations Might Have Given SARS-CoV-2 an Edge
The pandemic virus SARS-CoV-2 is thought to have originated in bats, like many viruses. To make the leap and infect anot ...
OCT 19, 2020
Plants & Animals
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
OCT 19, 2020
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
There are over two billion people around the world that don't get the recommended levels of minerals and vitamins in ...
Loading Comments...