The hepatitis A virus can trigger acute liver inflammation which generally has a mild course in small children but which can become dangerous in adults. The virus, which is found worldwide, has previously been considered to be a purely human pathogen which at most is found in isolated cases in non-human primates.
An international team of researchers under the direction of the University of Bonn has now discovered in a large-scale study with nearly 16,000 specimens from small mammals from various continents that the hepatitis A virus – like HIV or Ebola as well – is of likely animal origin. The results currently appear in the renowned journal “PNAS".
An infection with the hepatitis A virus can trigger acute inflammation of the liver which generally does not cause any symptoms in children and resolves without major complications. "In tropical regions, nearly all young children are infected with the hepatitis A virus and from that time on, they are immune to this disease," says Prof. Dr. Jan Felix Drexler from the Institute of Virology at the University of Bonn Medical Centre and the German Centre for Infection Research (DZIF). By contrast, if adults become infected with the hepatitis A virus, the symptoms can be more serious, and the disease can even have a fatal outcome. The virus has been found to date only in humans and a few non-human primates. Its origins were mysterious.
15,987 specimens from 209 different species of small mammals
Virologists from the University of Bonn Hospital, together with their colleagues from several German and international research institutes worldwide, searched for viruses related to the hepatitis A virus. They investigated a total of 15,987 specimens from 209 different species of small mammals: from rodents to shrews and bats to hedgehogs.
Viruses from these mammals are very similar to the human hepatitis A virus with regard to their genetic properties, protein structures, immune response and patterns of infection. "The seemingly purely human virus is thus most likely of animal origin," says Drexler. “The study enables new perspectives for risk assessments of emerging viruses by investigating functional, ecologic and pathogenic patterns instead of phylogeny only”.
The scientists' evolutionary investigations may even hint at distant ancestry of the hepatitis A virus in primordial insect viruses. "It is possible that insect viruses infected insect-eating small mammals millions of years ago and that these viruses then developed into the precursors of the hepatitis A virus," says the virologist from the University of Bonn Medical Centre.
Small mammals contribute to the preservation of the hepatitis A virus
The researcher assumes that small mammals were important hosts for the preservation and evolution of the viruses. "Otherwise the hepatitis A virus would actually have gone extinct long ago in small human populations due to the lifelong immunity of the persons once infected with it," Drexler reasons.
"However, patients need not fear that they could contract a hepatitis A virus infection through bats or hedgehogs. It has likely been a very long time since humans first contracted the hepatitis A precursor virus from animals – moreover, such incidents are very rare," says the virologist from the University of Bonn Medical Centre.
Publication: Evolutionary origins of hepatitis A virus in small mammals, “Proceedings of the National Academy of Sciences of the United States of America” (PNAS), DOI: 10.1073/pnas.1516992112
Prof. Dr. Jan Felix Drexler
Institute of Virology
University of Bonn Medical Centre
German Center for Infectious Disease Research (DZIF)
Johannes Seiler | idw - Informationsdienst Wissenschaft
What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering