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VIRUS H5N1 => ASIE - HUMAINS => Asie => Cambodge - Articles humains => Discussion démarrée par: ZOUZOU le 24 novembre 2005 à 10:09:05

Posté par: ZOUZOU le 24 novembre 2005 à 10:09:05

  Asia Pacific News »
Posted: 24 November 2005 1633 hrs

Mutated strain of bird flu found in Cambodia

PHNOM PENH: A mutated strain of bird flu has been found in samples taken in Cambodia, but it is not known if the new strain is more lethal than that which has killed four people here, health officials said.

Testing on the samples, which were collected in April, is continuing, said Philippe Buchy, head of the Virology Department at the Pasteur Institute office in the Cambodian capital Phnom Penh.

"We don't know yet if it has any significance for the transmission from humans to humans, or from birds to humans," Buchy said, adding that mutations of the H5 virus are common.

"I'm really not concerned about this. The strains have been seen by H5 experts from the (World Health Organisation's) networks and they didn't say anything."

Buchy said it was likely the strain found in Cambodia was similar, if not the same as a mutation reported earlier this month in southern Vietnam, where officials sought to ease fears that a deadlier form of bird flu had erupted.

No new cases of bird flu have been reported in either humans or animals in Cambodia since March, said Ly Sovann, head of the health ministry's infectious disease department.

But he also said the impoverished country does not have the means to test new strains of bird flu, making it more difficult to control future outbreaks.

Cambodia is located between Vietnam, where 42 bird flu deaths have occurred, and Thailand, which has seen 13 fatalities, according to the World Health Organisation's official figures since late 2003.

Two of the four bird flu victims from Cambodia, whose nationals regularly cross the porous border in the densely populated Mekong delta, died in southern Vietnam after being hospitalized in a Kien Giang hospital.

Scientists warn that the H5N1 virus, which has killed more than 60 people in Asia since late 2003, could mutate and combine with human flu variants, making it easily transmissible among humans and creating a global pandemic.

- AFP /ct
Posté par: Yves le 24 novembre 2005 à 13:20:15
Cette information concernant la mutation est-elle liée à celle donnée par Henry Niman concernant des échantillons de virus prélevés sur des cygnes en Mongolie?
Le site de clivage de l'hémagglutine y est différent:

The three sequences have polymorphisms that are unique for a given isolate, shared by 2 of the 3 swan isolates, or common to all three swan isolates but different than the other H5N1 isolates.  One polymorphism found only in the three swan isolates is A1059G in HA.  This changes the multi-basic cleavage site from RRRKKR to RRRRKR.  The former sequence is found in the first H5N1 isolate in Asia (Guangdong goose/96) and is present in most HPAI H5N1 in Asia.  There are few variations, such was the sequences from northern Vietnam that were missing one of the R's.  This deletion correlated with milder disease this year.
Niman indique que les trois séquences relevées sur des cygnes présentent des nouveautés par rapport aux souches connues qui sont soit présentes sur les trois échantillons, sur deux des trois ou sur un seul. Un des changements qui affecte les trois échantillons concerne le site de clivage multi-basique de l'hémagglutinine qui est A1059G (remplacement de A par G (ou de G par A??) en position 1059).  Le site de clivage passe de la séquence RRRKKR à RRRRKR (??).