When a virus or another organism causing a disease is transmitted from one species to another, most of the time, infection spits and dies. On rare occasions, infection can perpetuate transmission in new host species and cause a pandemic. For example, scientists keep an attentive eye on the highly pathogenic aviary H5N1, which causes the bird flu and was found in cows and humans. But is there a way to anticipate when the infections go out alone and when they persist?
New research, led by scientists from Penn State and the University of Minnesota Duluth, has identified certain characteristics that could help predict whether the pathogen will remain. Understanding how a virus spreads and what influences its spread shortly after its dissemination to a new population could provide information to prevent new diseases from spreading, the team said.
The study was published today (August 21) in the journal Biology Plos.
Pandemic prevention efforts are largely focused on identifying the next pandemic pathogen, but it is like finding a needle in the hay boot. This work helps us to determine the epidemics to fear so that we can direct our public health resources where they must go to prevent and respond to the emergence of diseases. “”
David Kennedy, associate professor of biology at Penn State and principal author on the newspaper
Although pandemics are extremely rare, overflow events – where viruses move between different host species – occur all the time, according to the research team. With so much viral transmission that occurs, it is almost impossible for scientists to determine what overflows to pay attention.
“We wanted to know if there is something that we can measure directly after an overflow event or if there are characteristics of an overflow event that would be predictive if the virus would persist or not in a new population,” said Clara Shaw, the main study of the study. Shaw was a postdoctoral scholarship holder in biology in Penn State at the time of research and is now an assistant biology professor at the University of Minnesota Duluth.
The researchers studied viral overflows in a system of models of verse, which allowed the team to examine the transmission and emergence of diseases at the level of the population rather than in individual animals, said Shaw. They have studied eight strains of worms which belong to seven species of the Caenorhabditis nematode, a model of disease of disease which shares a large number of genes with humans.
To induce an overflow event, the worms were exposed to the Orsay virus, a nematode virus. The worms of worms evaluated in the study are at least partially sensitive to the Orsay virus but vary in their ability to transmit it. The populations of worms have reproduced and increased between five and 13 days. Then, the researchers transferred 20 adults to a new petri without virus box where worms can reproduce and reproduce. They repeated this process, transferring verses to new Petri boxes up to 10 times or until the virus is no longer detected in the worms.
The researchers then measured specific traits of the population of verses remaining on the initial plate – what a fraction of the population is infected; How much virus is inside each infected worm; How many viruses do they lose; And how sensitive to virus are they? Using mathematical models, scientists examined each trait individually, then together to determine whether one of the characteristics was linked to the emergence of the virus because the worms were transferred to new plates.
The researchers found that the dynamics of how the virus spreads in the course of a few days after transmission is important to predict the long -term viral persisted. For example, three factors were all correlated positively with the fact that a virus takes off in the new host population – the prevalence of infections or the fraction of the infected exposed population; Viral parade or ability to release copies of the virus in the environment; and sensitivity to infections or the vulnerable from hosts to virus.
The prevalence of infections and viral excretion were particularly important, the researchers said. More than half of the differences observed in the question of whether the virus persists in the worms can be linked to these characteristics detected in the initial plate.
“This means that these first features can actually tell us a bit what will happen in the future,” said Kennedy.
The researchers also found that the intensity of the infection, or the severity of the infection, did not predict the persistence of the virus.
The researchers said they were planning to rely on this work. Then, they will explore how pathogenic agents adapt to new hosts to understand the evolutionary changes that occur at the genetic level. For example, Kennedy said they wanted to understand what genetic changes have allowed the pathogen to persist and when these changes have occurred.
The funding of the US National Science Foundation supported this work.
