H7N3: Viruses are common in birds

H7N3 is a very common type of influenza A virus in birds, according to a recent report by a group of US-Canadian scientists.

A team of US and Canadian scientists concluded after surveying 248 samples of avian influenza virus and several thousand gene segments collected from birds in the Alberta area and in the region. New Jersey coastal state from 2001 - 2006.

H7N3: The most common type of flu virus in birds

Lead researcher Scott Krauss - Children's Hospital St. St. Jude (St. Jude Children's Research Hospital), Memphis, USA. In addition, an expert in the field of influenza who participated in this study is Prof. Robert Webster, also from St. Peter's Hospital. Jude.

The most common types of influenza viruses in ducks are H4N6, H1N4, and H10N7, while in seabirds are H10N7, H1N9, and H7N3.Artwork (Photo: People.com.cn)

For six years, the team collected waste and blood from wild ducks in Alberta and fecal samples of seabirds in Delaware Bay, New Jersey. The researchers detected viruses causing influenza A in 98 out of 590 duck droppings (accounting for 16.6%) and in 114 out of 1,970 samples from seabirds (5.8%).

The most common types of influenza viruses in ducks are H4N6, H1N4, and H10N7, while in seabirds are H10N7, H1N9, and H7N3. No H5N1 type. In addition, serological tests of blood samples collected from about 700 ducks in Alberta in 2004, 2005, and 2006 were not traced to the highly pathogenic H5N1 virus.

Through the study of seabirds, the scientists obtained 27 types of H7 viruses, of which H7N3 accounted for 24.

Tests on chickens showed that the pathogen - unlike the H7N3 strain, caused a bird epidemic in the UK in 2004. However, after copying on chickens, the virus was fatal to chicken embryos.

Wild birds spread H5N1 virus?

The research group of BV St. Jude also investigated why the highly pathogenic H5N1 virus has not spread to the United States, although there are migratory routes for wild birds from both hemispheres overlapping.

The team analyzed 6,767 gene fragments and 248 complete genomes. They found that there were only 56 out of 6,767 gene segments (0.83%), a very low percentage of abnormal " outsider events " - that is, the gene segment belongs to a certain consortium (Asia - Europe or America) will appear on the remaining consortium viruses. This proves that the H5N1 virus that has been fully inherited between the east and west hemispheres is very rare. Research results show that influenza viruses have changed in the two hemispheres.

The role of migratory birds in spreading highly pathogenic H5N1 virus has been debated for a long time. Thousands of migratory birds died of H5N1 infection in Lake Quinghai, the largest wild bird sanctuary in China, and then a series of outbreaks in Asia, the Middle East, Europe and Europe. Africa.

According to an earlier report by the US Department of Agriculture and the Department of the Interior, about 109,000 birds were inspected from April 2006 to March 2007. The H5N1 strain of virus in lower North America has been found in several species of birds living in the United States. Many studies conducted by Canada from 2006 - 2007 did not find highly virulent viruses.

According to scientists, highly pathogenic H5N1 viruses can be transmitted in the western hemisphere through legally or illegally imported birds rather than wild birds.

However, scientists continue to closely monitor wild birds.

Sand incense
Center for Infectious Diseases - Center for Infectious Disease Research & Policy - University of Minnesota, USA, Vietnamnet