NEW BIRD INFLUENZA STRAIN WORRIES SCIENTISTS : H7N9 IS A VIRUS BY STEALTH SO FAR

 

photo: France24

A series of reports on the newly viral strain of H7N9 is putting the World Health Authorities on alert.

But closer examination of  the virus, which has now been confirmed in pigeons in Shanghai and which might be traveling the migratory bird routes, has a peculiar quality that is worrying scientists.

Apart from its ability in crossing the zoonotic barrier, which was not the case before as this strain was considered benign to humans, it now seems to have another dangerous characteric: the ability to infect birds and poultry without the infected animal showing any signs of illness.

In the past most avian influenza was monitored from chicken or other bird deaths.  Now the birds that are infected seem to be perfectly healthy, at least as far as the specimens that have been identified go.

This is causing concern because the area of infection is growing rapidly, even though the number of cases is still very low, and that shows that the virus might already be widespread, with no tell tale signs to alert the health authorities.

Apart from showing a high mortality rate so far, even though that could change when the total number of cases are tallied, the virus has not acquired the ability to be trasmitted from human to human, but its monitoring is nearly impossible if the infected animal turns out to be a healthy carrier. 

Most of the cases so far entirely overlap the migratory routes of some birds.  With the unusual cold spring of this year, many birds are finding themselves at a loss in how to proceed, since their usual habitats are still frozen and there is no food for them.  This in itself could presage a wider spread of the disease if the birds continue south out of necessity, but it could also brake the spread of the disease if the birds die in high numbers due to the lack of food available when they arrive at their destination.

However, there have been so far, no direct clues as to the provenance of the disease.  

In addition the strain of H7N9 that is infecting Chinese people has already undergone many mutations that allowed it to cross the zoonotic barrier and there is no way of knowing what pandemic potential it has at the moment.  

There has already been talk of companies gearing up for a vaccine run to prevent a pandemic for this winter, and forego production of routine vaccine, but at this time there is no firm decision yet. Some scientists however contend that it is too late to prevent an epidemic for this year even if it would erupt as late as winter. 

One of the advantages of this virus being new to the human body, is that it is susceptile to both influenza antiviral drugs available on the market.

Because this virus had never crossed the zoonotic barrier before, the human body has no immunity against it and it would make humans highly susceptible.  

partial source: 4.5.13