NewsDesk @bactiman63

In a follow-up on the H5N1 avian influenza cases reported in Cambodia this week, the Cambodian CDC announced on their Facebook page today that the clade identified is 2.3.2.1c.

Here’s what they wrote (computer translated):

Currently, February 26, 2020

Image/Cambodia MOH

Bird flu virus H5N1, which is the cause of death of girls living in Rolang village, Khlach commune, Central Sitha district, is a virus that has been studied among local birds, wild birds in Cambodia during the last few years.

Bird flu H5N1 (clade 2.3.2.1c): Different from H5N1 bird flu in other countries around the world.

Monitoring of the disease is ongoing, while the population in contact with the patient remains monitored.

As of today, there has not been any clear evidence of transmitting H5N1 bird flu from person to person.

Request all citizens to avoid direct harm with sick or dead birds. Let’s protect and prevent together for our health.

For more information, please contact phone number 118

From the World Health Organization:

A(H5) viruses from birds and non-human mammals characterized from September 2022 to February 2023 belonged to the following clades:

Clade 2.3.2.1a viruses were detected in poultry in Bangladesh. There were up to 10 amino acid substitutions in the HA of recent viruses compared to the HA of A/duck/Bangladesh/17D1012/2018, from which a candidate vaccine viruses (CVV) has been developed. Some of the recent viruses did not react well to a post-infection ferret antiserum raised against the A/duck/Bangladesh/17D1012/2018 CVV but instead reacted well with a post-infection ferret antiserum raised against the A/duck/Bangladesh/19097/2013 CVV.

Clade 2.3.2.1c viruses were detected in birds in Viet Nam and Lao People’s Democratic Republic. Viruses from Viet Nam reacted well with a post-infection ferret antiserum raised against the A/duck/Vietnam/NCVD1584/2012 CVV, despite recent strains having up to 9 amino acid substitutions in the HA.

Clade 2.3.2.1e viruses were detected in Timor-Leste. The HAs of these viruses were most closely related to viruses previously detected in Indonesia. There are no CVVs representative of this HA clade and the viruses from Timor-Leste reacted poorly with post-infection ferret antisera raised against clade 2.3.2.1a and 2.3.2.1c CVVs. No human infections have been associated with viruses of this clade and the extent of their circulation is uncertain.

Clade 2.3.4.4b viruses were detected in birds in many countries in Africa, Asia, Europe, North America and, for the first time, in Central and South America. An increasing number of infections in wild and captive mammals has been reported, with mink-to-mink transmission suspected on a farm in Spain. Viruses from this clade have been associated with several different NA subtypes with N1 now predominating. The high levels of infection in birds with these viruses and increased geographic distribution have been accompanied by genetic diversification. Some A(H5N1) viruses from Europe, the United States of America (USA) and Viet Nam show reduced reactivity with post-infection ferret antisera raised against the A/Astrakhan/3212/2020 CVV. All viruses from Europe reacted well with post-infection ferret antiserum raised against A/chicken/Ghana/AVL763_21VIR7050-39/2021; a representative CVV is being developed. Many viruses from the USA that had reduced reactivity with antisera raised against the A/Astrakhan/3212/2020 CVV showed better reactivity with post-infection ferret antisera raised against A/American wigeon/South Carolina/22-000345-001/2021.

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The US Centers for Disease Control and Prevention writes: HPAI A(H5N1) virus infections have been reported in more than 880 people with approximately 50% case fatality proportion since 1997, including 20 cases and 7 deaths in Hong Kong during 1997-2003, and more than 860 cases reported in 21 countries since November 2003. Mild upper respiratory tract symptoms, lower respiratory tract disease, severe pneumonia with respiratory failure, encephalitis, and multi-organ failure have been reported. One case of asymptomatic infection was reported in Vietnam in 2011, and another asymptomatic case was reported in the United Kingdom that occurred in late 2021. The spectrum of illness caused by human infection with current H5N1 bird flu viruses is unknown. Since 2016, a small number of sporadic infections have been reported each year globally. Illness in humans from all bird flu virus infections has ranged in severity from no symptoms or mild illness to severe disease that resulted in death.