A single mutation can put a flu virus on a new-enough path to re-infect people who had developed immunity to its previous form, said Katia Koelle, a Duke assistant professor of biology.
For example, a commonplace Influenza A virus known as H3N2 emerged in 1968. But since then fully one-third of the component amino acids in its hemagglutinin protein -- the "H" in H3N2 -- have changed.
"That's a huge amount of evolution," Koelle said. "If there's a new escape mutant that can actually so change the protein's configuration that our antibodies can't recognize the virus anymore, that means it's going to have a huge advantage and infect more of us.
"How much of an advantage the new virus strain has will depend on how many people have gotten infected in the past. So the epidemiological dynamics will shape the evolutionary dynamics. And vice versa, the evolutionary dynamics will shape the epidemiological dynamics because mutations of the virus will allow people to become re-infected."
Koelle's group at Duke has developed a two-tiered model to simulate that interplay in such viruses, allowing scientists to "quantitatively reproduce the patterns we observe," she said.
Koelle is scheduled to describe her work at 10:25 a.m. Wednesday, Aug. 5, during a symposium (http://eco.confex.com/eco/2009/techprogram/S4132.HTM) at the 2009 Ecological Society of America annual meeting in Albuquerque.
"We're interested in having a flexible and simple model that would not only be able to reproduce the dynamics of H3N2 but also help us understand how flu evolves differently in different hosts," Koelle added. For example, H3N2 (not to be confused with the H1N1 "swine flu" virus) also has been circulating in pigs, with the virus showing distinctly different evolutionary patterns in these hosts.
One of her group's models is focusing on that difference, which she suspects is linked to man's and animals widely disparate lifespans -- about 80 years for humans versus under 2 for farm-raised hogs.
"The virus doesn't have to evolve rapidly to avoid being wiped out by the pigs' immunity to it," she said. "That's because there are always many more susceptible new hosts coming into the pig population."
Another challenge is Influenza B, a comparatively mild virus that infects mostly children but is complicated by the fact that two genetically distinct strain lineages circulate in human populations. During any given flu season, only one B sequence predominates, presenting a challenge for vaccine makers who must choose between them.
"They have to make an educated guess about which influenza B lineage is going to be the main one that season," Koelle said. "Sometimes there is a big B outbreak when it turns out to be the one not included in the vaccine."
Monte Basgall | EurekAlert!
Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.
How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences