Bird Flu H5 Versus H9
Poultry farmers in Indonesia are worried about a phenomenon they call the 90-20-60 disease.
Poultry farmers in Indonesia are worried about a phenomenon they call the 90-20-60 disease.
This disease affects the production of chicken eggs, which can drastically drop from 90 percent to 20-40 percent and then rise again to 60 percent.
There are many factors that cause the decrease in production, such as the type and quality of chicken feed, environmental conditions or poultry diseases such as Newcastle disease, infectious bronchitis, egg drop syndrome, encephalomyelitis, the Tembusu virus, bacterial infections, fungi, and many others.
Poultry farmers already know how to deal with these diseases, such as through vaccinations, treatment and environmental hygiene. However, this is not the case with the 90-20-60 disease.
According to a report released in 2016, the 90-20-60 disease is caused by the H9 influenza virus strain. The government was urged to allow the use of H9 flu vaccines in poultry.
Reportedly, the government has prepared the production of the H9 vaccine, as well as a vaccination program. If it is implemented, Indonesia will have two kinds of bird flu vaccines, namely to treat the H5 and H9 virus strains. However, as with the H7 and H10, both are zoonoses that can be transmitted to humans or vice versa.
Character of the H9 virus
There are currently more than 170 influenza strains with 17 hemagglutinin (HA) surface proteins and 10 types of neuraminidase (NA). Because influenza viruses also have six to eight different internal proteins, each strain has a variety of characters.
The most concerning ones are the avian influenza viruses, H5N1 and H7N9, as they are zoonoses and can kill humans. The H9 virus consists of strains H9N2 and H9N9. It was first isolated and identified in 1988 from migratory birds that stopped in China. That same year, it was successfully isolated from pigs, and a year later, from humans.
The spread of the H9 virus has stretched from the Middle East to the Far East. In Indonesia, it was found in humans by chance in 2013-2014, when H9 antibody vaccines were conducted on poultry and non-poultry farmers.
Another characteristic of the H9 flu virus is that it can bind to receptor cells, namely 2.3 and 2.6 alpha.
Unlike in the H5 bird flu virus, the receptor cell 2.6 alpha is dominant. In seasonal H1 and H3 flu viruses in human receptors, the 2.6 alpha is also dominant.
The transmission of H9 in poultry is mainly through the large intestine, meaning through the digestive tract, as well as through breathing. Given that the H9N2 is a human flu virus, the emergence of the H9 virus in birds came from humans, unlike the H5, in which transmission is from birds to humans.
The H9 is known as the best flu virus donor to other viruses, meaning that other viruses that receive donor genes can change their nature and characters. The Isolation and purification of H9 from other germs is so difficult that special methods are needed to purify it.
For example, when combined with H9, the H7 virus can infect the human body, and several human victims have been recorded. Currently, the H7 is more feared than H5 as a source of a global epidemic.
The H9 is not a malignant virus (low pathogenic Avian Influenza/LPAI) that can be found in the body of poultry and humans.
Research published in Veterinary Research in 2016 concluded that the decline in egg production caused by the H9 was initiated by a replication in the oviduct, precisely in the magnum.
As a result, the outer (epithelial) tissue of magnums is damaged by the release of viruses from the cell. The problem is that magnum cells have a protein-producing gene that regulates the flow and metabolism of calcium in forming egg shells. Shell depletion reaches 75 percent on the fifth day of an H9 infection.
The disorder is believed to be the main cause of the decline in egg production. However, on day six and seven, the fallopian tubes return to normal. The description of the decrease in egg production caused by H9 is different from the decrease in production caused by other factors.
Vaccination of H5 and H9 viruses
During H5 avian influenza outbreak in 2003, which killed millions of poultry and even people, Indonesia successfully established a H5 virus vaccination program in poultry to save poultry farms. This program is still running.
Economically, H5 vaccination is not so beneficial because it hampers the exports of poultry products. Several countries have stopped importing poultry from Indonesia. As a result, the country’s poultry breeders do not have an “emergency door” when the domestic market declines.
The H5 vaccination program has lasted more than 12 years. Is there a possibility to stop it? Conversely, without an H9 vaccination program, egg production will continue to decrease
However, there is still a way to overcome this dilemma. Especially if the H9 is left in its natural state, the impact of a coalition with other influenza viruses can still be anticipated.
If the H9 vaccination plan is still implemented, along with the H5 vaccination program, the question is how to stop the spread of the H9 virus in poultry.
In addition to causing poultry sensitization against the H9 and other viruses, vaccination also allows the H9 to mutate and change its characteristics. In fact, the results of a possible coalition of the H5 and H9 are difficult to predict.
The results of research conducted by Dr. Hoa and his team from Yangzhou University, China, published in Frontiers in Microbiology in 2017, are very interesting to note.
The H5N1 coalition with H9N2 genotype S can produce a new H5 that has pathogenic characteristic and slow killing power.
The results also show that the transmission model is changing. The original mode of transmission is through the air, but the coalition changes it to direct contact.
In conclusion, creatures as small as influenza viruses have their own ways of life. Man must be able to understand their own characters to reduce health and economic risks.
CA Nidom
Professor of vaccinology and bioterrorism studies at Airlangga University in Surabaya, East Java.