On February 26, 2023, the Institut Pasteur du Cambodge, in collaboration with the Cambodian Ministry of Health, shared the full genetic sequence of the H5N1 virus recovered from the patient who died in that country on February 22, 2023. The genetic sequence of the second case was later also shared by the Institut Pasteur du Cambodge. CDC has conducted a preliminary analysis of the genetic sequences of these H5N1 bird flu viruses. They are H5N1 viruses from clade 2.3.2.1c, which are different from the H5N1 viruses now spreading in U.S. wild birds and poultry, which are from clade 2.3.4.4b. These viruses are similar to past 2.3.2.1c viruses detected in that geographic area over recent years. The genetic sequences suggest that an existing clade 2.3.2.1c candidate vaccine virus (CVV), called NIBRG-301 (A/duck/Vietnam/NCVD-1584/2012-like) would offer protection against the viruses identified in Cambodia.
Poultry farms are a key battleground in the fight against H5N1, the strain of avian influenza and some countries including China has started to vaccinate poultry to limit the spread and severity of bird flu, and other governments around the world are now implementing vaccination policies or contemplating doing so.
One problem with existing vaccines is that they cause birds to test positive for the virus, meaning farmers can’t guarantee their birds are free of H5N1. This poses huge international trade and export implications.
Some US researchers are working on a vaccine that will not have this problem by developing a vaccine that uses only a small part of the virus’s DNA.
H5N1 can infect non-human mammals, including sea lions, otters, mink, foxes, cats, and dogs. But there's no evidence of human-to-human transmission. There are a couple of valid scientific reasons why it is so..
H5N1 can infect and replicate in cells of the lower respiratory tract, its transmission to other humans from the lower respiratory tract is very inefficient, and also H5N1 cannot efficiently replicate in the upper respiratory tract, so it doesn’t typically transmit among humans. (Unless an amino-acid change takes place it cannot bind into a receptor)
There's no way to guarantee that a mutation will not happen. If that happens the mortality rate from H5N1 infection in humans is estimated to be higher than 50% (compared to less than 1% from Covid), - the consequences of a potential H5N1 pandemic would be a lot worse than the present pandemic.
Poultry farms are a key battleground in the fight against H5N1, the strain of avian influenza and some countries including China has started to vaccinate poultry to limit the spread and severity of bird flu, and other governments around the world are now implementing vaccination policies or contemplating doing so.
One problem with existing vaccines is that they cause birds to test positive for the virus, meaning farmers can’t guarantee their birds are free of H5N1. This poses huge international trade and export implications.
Some US researchers are working on a vaccine that will not have this problem by developing a vaccine that uses only a small part of the virus’s DNA.
H5N1 can infect non-human mammals, including sea lions, otters, mink, foxes, cats, and dogs. But there's no evidence of human-to-human transmission. There are a couple of valid scientific reasons why it is so..
H5N1 can infect and replicate in cells of the lower respiratory tract, its transmission to other humans from the lower respiratory tract is very inefficient, and also H5N1 cannot efficiently replicate in the upper respiratory tract, so it doesn’t typically transmit among humans. (Unless an amino-acid change takes place it cannot bind into a receptor)
There's no way to guarantee that a mutation will not happen. If that happens the mortality rate from H5N1 infection in humans is estimated to be higher than 50% (compared to less than 1% from Covid), - the consequences of a potential H5N1 pandemic would be a lot worse than the present pandemic.
