Avian influenza is likely to make a comeback, experts say, as a recent study found the presence of the virus to a great extent in the air samples collected from the districts adjoining Dhaka. In 2008, when this virus spread, there was widespread panic since over 500 chicken farms had to be burned and destroyed in 52 districts.
The risk of avian influenza infection has been seen in the blood that spreads in the air during the slaughtering of poultry chickens infected with the avian influenza virus (AIV).
Eight “human cases” of influenza A H5N1 and A H9N2 have been reported in Bangladesh since 2008, the study said. Most of these cases were linked to poultry slaughter or handling. The influenza particles (aerosols) produced by live poultry markets can be an important source of avian influenza infection in humans.
The study results were presented at the Ninth International Influenza Summit of the European Scientific Working Group on Influenza (ESWI), held recently in Valencia, Spain.
The research, titled “Detection of Avian Influenza Aerosol Particles in Peri-urban and Rural Live Bird Markets Outside Dhaka City, Bangladesh, during Poultry Slaughtering”, was conducted by 11 experts from the International Centre for Disease Research Bangladesh (Icddr,B), the University of London, and Bangladesh Agricultural University.
Samples were collected from different markets in Manikganj, Gazipur, Narayanganj, and Munshiganj districts from January to March 2023.
According to the researchers, this study will inform the government about the prevailing situation to prevent the spread of avian influenza. Governments can also take initiatives to reduce the aerosolization of virus particles during the slaughter and processing of poultry and reduce the risk of spillover.
The air samples were collected from poultry shops in urban and rural areas using National Institute for Occupational Safety and Health bioaerosol and bioaerosol cyclone samplers. After field processing, the samples were tested for influenza A, H5, H7, and H9 subtypes by real-time one-step reverse transcriptase polymerase chain reaction (RT-PCR) at the icddr,b laboratory.
The results showed that 52 of a total of 64 air samples (80%) and 139 of 192 subsamples (72%) were positive for influenza RNA.
Prof Dr Aminul Islam Bhuiyan of the Zoology Department at Dhaka University said that avian influenza had spread in Bangladesh before.
“From the perspective of Bangladesh, this virus is not very harmful to the human body, but we have to be aware like the developed world.”
What to do
Bangladesh's open market environment for poultry slaughtering and processing can generate aerosols containing AIV, which the study claims is dangerous.
When there is an outbreak of the virus in a farm or area, it should be isolated immediately to stop the spread of the virus.
There is no reason to burn chickens or farms if the virus is infected, he said.
“It is difficult to eradicate a disease caused by a virus, but it is possible to control it. Sometimes it gets eliminated due to natural causes,” Prof Aminul added.
