H5N1, Bird Flu Updates - Page 11

Leslie Reperant of Princeton University in the United States and Thijs Kuiken of the Erasmus Medical Centre in the Netherlands said their findings offered a possible way to predict and control where and when bird flu might erupt again.

"Forecasts predicting near-freezing temperatures in Europe may act as an indication for concern," they wrote.
They found that most H5N1 outbreaks occurred at sites where maximum temperatures were between 0 degrees Celsius and 2 degrees Celsius. This was usually on the edge of cold fronts where fresh water remained unfrozen.
"Many wild waterbirds need unfrozen bodies of fresh water in winter to feed," they wrote.

"To minimise the distance flown, they also try to stay as close as possible to the northern breeding grounds to which they will migrate during spring...The resulting congregation of different species of waterbirds along the freezing front likely created ideal conditions for the transmission of the H5N1 virus."

The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences.

We demonstrated that H5N1 jumped from poultry to another mammalian host; donkeys. Phylogenetic analysis showed that the virus clustered within the lineage of H5N1 from Egypt, closely related to 2009 isolates. It harboured few genetic changes compared to the closely related viruses from avian and humans. The neuraminidase lacks oseltamivir resistant mutations. Interestingly, HI screening for antibodies to H5 haemagglutinins in donkeys revealed high exposure rate.
Conclusions

These findings extend the host range of the H5N1 influenza virus, possess implications for influenza virus epidemiology and highlight the need for the systematic surveillance of H5N1 in animals in the vicinity of backyard poultry units especially in endemic areas.

...The HA and NA sequences from A/equine/Egypt/av1/2009 have been placed on deposit at Genbank and the HA sequence has the 3 BP deletion previously reported in mild cases in Egypt.

The milder cases were first noted in 2007 and then attracted considerable interest because of the large number of mild cases in young children in 2009. The sequences from these milder cases contained the 3 BP deletion, raising concerns that the deletion allowed for efficient spread of H5N1 in humans, which was largely undetected because of the mild nature of the infection.

The discovery of this H5N1 in mild infections of donkeys raises significant concerns. H5N1 has not been reported in equine previously, although its host range includes many mammalian species. The potential role of the 3 BP deletion raises concerns that H5N1 may be much more widespread in humans. The same deletion has been reported in clade 7 in China, raising additional concerns of human infections.

in addition, the equine isolate lacks aa s145. this deletion is also present in all other viruses grouped into 2.2 sublineage a1, which also includes sequences from human h5n1 isolates (fig. 2). the significance of this deletion is unknown, but it should be noted that this position is close to a domain modulating receptor interaction.

interestingly, strains with this deletion appear to evolve towards a receptor usage that is similar to that of the seasonal human h1n1[31].

the above comments are from the paper, “isolation and characterization of highly pathogenic avian influenza virus subtype h5n1 from donkeys” and notes the prior paper on h5n1 in egypt which identified sequences with the 3 bp deletions as those most likely to have a high affinity for human h1n1 receptors. sequences with the deletion were of interest because they were linked to mild cases of h5n1 in egyptian children in 2007 and 2009. the sequences in 2007 included closely related sequences in southern egypt, raising concerns of human to human transmission. these concerns increased in 2009 when virtually all initial confirmed cases were mild and in toddlers.

it was at this time in early 2009 that the h5n1 was isolated from donkeys, a/equine/egypt/av1/2009, and as noted above had the same deletion. moreover, the donkeys were only symptomatic for three days and there were no fatalities. further serological analysis indicated the h5n1 was widespread in donkeys in the beni suef governorate, and therefore were likely throughout egypt because in 2009 the h5n1 with deletion was the most common h5n1 sub-clade detected in egypt in humans and poultry, including waterfowl.

the detection of h5n1 in donkeys raised concerns that h5n1 was also in horses and camels as well as other mammals, including humans, but was not described because of a lack of testing / reporting, which extends to other regions and sub-clades.

the identical 3 bp deletion was also found in china in clade 7 in shanxi and hunan province in 2006, raising concerns of widespread transmission in mammals in china including humans. the lack of testing / reporting increases those concerns. the mild nature of many of the cases in egypt raise concerns of silent spread and recombination in humans or other mammals co-infected with ph1n1, giving rise to more recombinants including h5n1 which is more transmissible in humans, or h1n1 which is more lethal in humans.

A 27-year-old man in eastern Cambodia has died of bird flu, the country's first fatality this year and its eighth since the virus started to sweep through Asia almost seven years ago.

Cambodia's Health Ministry said in a statement issued jointly Wednesday with the World Health Organization that the man in Prey Veng province died Saturday. It was the country's 10th human case of the disease.

MORE than 1,000 ducks and chickens in Prey Veng province’s Kampong Leav district are believed to have died after contracting the A(H5N1) virus, known as bird flu, and a further 1,500 will soon be tested for the disease, a health official said Thursday, just over a week after a man from the same district became the eighth person to die of the disease since it was first detected in Cambodia in 2004.

Chhun Dy, the district’s chief of animal health, said officials would await test results from the 1,500 animals before deciding whether to begin culling.

Sok Touch, director of the Health Ministry’s Communicable Diseases Control Department, said officials had warned villagers to stay away from the area where the infected poultry died. Kao Phal said that area had been “cleaned”.

Indonesian media is reporting the 4 year-old girl who died on Wednesday in the flu isolation unit of Arifin Achmad hospital in Pekan Baru, Indonesia has tested positive for the H5N1 virus.

Meanwhile, three others from the same region remain hospitalized with suspected H5H1 infection. A 40 year-old mother, her 14-year-old child, and an 8-year-old neighbor.

Their conditions are reported as improving.

indonesia: suspected bird flu spreads to other villages

via ida at bird flu information corner, a report from riau pos: sungaiapit, riau ::: bird flu spreads to other villages. excerpt:
bird flu h5n1 had spread to desa parit i/ii, desa harapan and kelurahan sungaiapit since it was firstly identified in desa lalang. until now, bird flu infected human suspect has reached nine victims. two of them are now being treated at arifin achmad hospital in pekanbaru, while others are refused to be hospitalized.

ida has another report, from west sumatera, about a widespread outbreak of b2b h5n1 and one suspected human case, an 11-year-old boy.

a farmer shows carcasses of two openbill storks among thousands which have died in ayutthaya’s phak hai district. residents fear bird flu is the cause of the deaths. photo: sunthorn pongpao
a vast wasteland in tambon khok chang of ayutthaya is home to tens of thousands of asian openbill storks (nok pakhang). it is one of the largest flocks of birds in ayutthaya.

a few days ago thousands of asian openbill storks died without apparent cause.

residents are worried the flock might have been infected with the bird flu virus as phak hai district was one of many areas nationwide reported with the virus outbreak last year.