Warm-up slows avian flu spread

[Snowy Owl]

[SIZE=+2]Warm-up slows avian flu spread
http://www.newsday.com/news/health/ny-hsbird064731578may06,0,1721108.story?coll=ny-health-print

[/SIZE]BLOOMBERG NEWS

May 6, 2006

Bird flu is spreading more slowly as warmer spring weather in the Northern Hemisphere reduces the virus' ability to survive in the environment, world health experts reported Friday.

Five outbreaks of the lethal H5N1 avian flu strain in poultry were reported to the World Organization for Animal Health in the week ended April 27, compared with an average of more than 40 a week in March. Diseased fowl raise the risk for humans and create opportunities for the virus to change into a form that could spread more easily among people.

Scientists are counting on the slowdown in animal infections to reduce the number of human cases and fatalities. At least 29 people died of avian flu in the first three months of this year, marking the deadliest quarter yet, as the virus spread through Europe and Africa.

"The peak transmission either in poultry or to humans is in the winter months," said Robert Webster of St. Jude Children's Research Hospital in Memphis, Tenn. Webster has studied flu viruses for more than 40 years.

Tests have shown that H5N1 can survive in bird feces for at least 35 days at about 39 degrees Fahrenheit, the World Health Organization said in January.

"Maybe one of the more positive possibilities is that the summer is coming and the heat of Africa may be in our advantage," Webster told reporters in Singapore, where he addressed an avian flu forum this week sponsored by the Lancet medical journal. "Maybe we will have a summer before it starts spreading more."

The H5N1 virus has killed at least 114 of 206 people infected since late 2003, the Geneva-based WHO said.

In almost all human H5N1 cases, infection was caused by close contact with sick or dead birds, such as children playing with them, or adults butchering them or taking off the feathers.

The WHO is tracking human cases in the event the virus becomes easily transmitted from person to person, sparking a pandemic such as the 1918 outbreak that killed as many as 50 million people worldwide.
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[Goju]

Re: Warm-up slows avian flu spread

Why don't i believe this?

 

[Bruce]

Re: Warm-up slows avian flu spread

37 degrees C is the human temperature, birds are at some close by, the virus seems to survive fine and thrive in the bird body temperature.<o =""></o>
Now if the outside temperature gets to 37 C over here BF doesn’t mater anymore the main concern being water rising 21 feet.<o =""></o>

 

[Mingus]

Re: Warm-up slows avian flu spread

The problem could be more that the virus need to stay in water (in the water or in an air or a surface aerosol microdropping) to stay functionnal.

In most of the Standard lab procedure, the samples must be kept in a sterile saline or culture media before to be process or store.
The failure to perform this can lead to bad result or false negative.
We do that in our lab and other do it too as state by others ...

http://www.recombinomics.com/News/04120601/H5N1_Surveillance_GB.html

Recombinomics Commentary
April 12, 2006

The weekly magazine said its suspicions were raised because samples of droppings from more than 3,000 wild birds taken for DEFRA last December by the conservation group The Wildfowl and Wetlands Trust (WWT) showed only 0.06 percent had the ordinary flu that ducks and geese normally carry.

Crommie said DEFRA told the WWT samplers to take fecal samples on a sterile moistened swab and to put them in dry plastic tubes before freezing. But the independent experts said the samples would need to be immersed in a saline or preservative solution before being frozen.

"If you left a swab in the refrigerator in its sheath like that, it could dry out and your would lose all your virus," said Bjorn Olsen, of the University of Kalmar in Sweden, who tests 10,000 birds each year for avian flu.

Since air and the whole environment is more dry in the summer, we can understand more why the epidemic peak in human and in birds is in the summer at the exception of the tropical areas where the atmosphere is wet all year long and flu is endemic all year long too.

You also can understand why it seem to have a contradiction between this statement and the fact that the virus can replicate in bird body temperature as high as 27 to 29oC if you just consider temperature.

 

[Shannon Bennett]

Re: Warm-up slows avian flu spread

There are other factors to take into consideration. Warmer temps make surfaces dry out faster. The virus lives longer on wet or damp surfaces then it does on dry surfaces. The virus does live longer in cooler temps then it does in warmer ones. It is just a matter of degree. Since we have had an outbreak in China now it appears that if you get enough birds together in one place the infection is still being passed between birds.
It will be interesting to see what happens later in the early summer when the new chicks have begun to fledge and begin to flock. I'm guessing here as I am not an ornithologist but, while nest building is going on there may be subsequent semi-isolation. The only common source of infection would be in the water sources, as we have already suspected and, in the poop-laden grasses being grazed by the waterfowl.

 

[Mingus]

Re: Warm-up slows avian flu spread

it appears that if you get enough birds together in one place the infection is still being passed between birds.

Like a critical mass (critical viral load).

That's why gregarious species like gooses(that also follow wet and cool temperature) seem to be the majors spreaders.
They always keep the virus's ecosystem perfect.

 

[AlaskaDenise]

Re: Warm-up slows avian flu spread

...while nest building is going on there may be subsequent semi-isolation.

This is what Alaskan scientists are saying about the migratory birds here.

Once the young are able to leave the nest and learning to fly, we can expect more virus mixing (& new combinations). Our state scientsts are looking to August as the most important month for testing. That's when the first migratory birds leave here.

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