Disease predictions are like weather forecasts: we cannot predict the finer details for a particular outbreak or a certain storm, but we can often identify when these threats appear and prepare accordingly.
Viruses that cause bird flu are potential threats to global health. The latest outbreaks of subtype animals, called H5N1, are particularly disturbing to scientists. Although human infections from the H5N1 are relatively rare, there are just over 900 known cases worldwide since 2003 – nearly 50% of these cases are fatal – mortality by about 20 times higher than that of the influenza from 1918. If the worst of these rare infections may have occurred among people.
By approaching the potential threats to anthropological diseases, my colleagues and we recently published a book called “emerging infections: three epidemiological transitions from prehistory to the present” to study the ways in which human behavior has formed the Evolution of Evolution of the Neo -Neo Diseases.
From this perspective for a deep time, it becomes obvious that the H5N1 shows a common model of a step -by -step invasion from animal to human populations. Like many emerging viruses, H5N1 makes gradual evolutionary changes that could allow him to transmit between people. The periods between these evolutionary steps are opportunities to delay this process and possibly prevent a global catastrophe.
Overflow and viral chatter
When a pathogen causing a disease, such as influenza virus, is already adapted to infect a certain type of animal species, the ability to infect a new species can eventually develop, like humans, through a process called transfusion.
Transfusion is a complex enterprise. In order to be successful, the pathogen must have the right set of molecular keys, compatible with the host’s molecular “locks” so that it can enter and exit the host’s cells and distract their replication machines. As these locks often vary between species, the pathogen may need to try many different keys before it can infect a whole new type of host. For example, the keys that the virus successfully uses to infect chickens and ducks may not work on cattle and humans. And since the new keys can only be made through any mutation, the chances of getting all the right ones are very thin.
Given these evolutionary challenges, it is not surprising that pathogens are often struck in the transfusion process. A new variant of the pathogen can only be transmitted by an animal to a person who is either more susceptible due to an existing disease or more likely to be infected due to prolonged exposure to the pathogen.
Even then, the pathogen may not be able to escape from his human host and pass on to another person. This is the current situation with H5N1. In the last year, there have been many outbreaks of animals in various wild and domestic animals, especially among birds and cattle. But there are also a small number of human cases, most of which have occurred among poultry and dairy workers who have worked closely with a large number of infected animals.
Epidemiologists call this situation viral chatter: when human infections occur only in small, sporadic foci that look like coded radio communications – small outbursts of unclear information that can add to a very sinister message. In the case of viral chatter, the message would be a human pandemic.
Sporadic, individual cases of H5N1 among humans suggest that a transmission from person to person may occur at some point. But even so, no one knows how long or how many steps it would take to happen.
Glip viruses develop rapidly. In part, this is because two or more flu varieties can infect the same host at the same time, which allows them to adjust their genetic material with each other to produce completely new varieties.
These redirection events are more likely to appear when there are a varied set of hospitable species. So it is especially concerned that H5N1 is known to have infected at least 450 different animal species. It may not be long before the viral talk is back to more human epidemics.
Trajectory
The good news is that humans can take major measures to slow down the evolution of H5N1 and potentially reduce bird flu death if it ever becomes a common human infection. But governments and business will have to act.
People can start by caring better for nutrients. The total weight of poultry is more than all species of wild birds combined. So it is not surprising that the geography of most H5N1 outbreaks follows more closely with large-scale dwellings and international transfers of living poultry than with the models of nesting and migration of wild water birds. Reducing these agricultural practices can help limit the evolution and distribution of H5N1.
People can also take better care of themselves. At the individual level, most people can vaccinate against common, seasonal influenza viruses that spread every year. At first glance, this practice may not seem to be related to the appearance of bird flu. But in addition to preventing seasonal diseases, vaccination against ordinary human varieties of the virus will reduce the chances of mixing with bird varieties and give them the features they need to transmit from person to person.
At the population level, societies can work together to improve nutrition and sewage in the world’s most population. History shows that better nutrition increases the overall resistance to new infections, and better sanitation decreases how much and how often people are exposed to new pathogens. And in today’s interconnected world, problems with the disease of every society will eventually spread to every society.
For more than 10,000 years, human behavior has shaped the evolutionary trajectories of infectious diseases. Knowing this, people can change these trajectories to better.
This article is reissued by the conversation, a non -profit, independent news organization that brings you facts and a reliable analysis to help you make sense of our complex world. It is written by: Ron Barrett, Macalester College
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Ron Barrett does not work, consults, holds shares or receives funding from any company or organization that would benefit from this article and does not reveal a corresponding relationship outside their academic appointment.