#18,003
With so much attention currently focused on HPAI H5N1 clade 2.3.4.4b, it is easy to forget that it is just one of many avian influenza viruses (e.g. H5N6, H7N9, H9N2, H3N8, etc.) with zoonotic potential.
While they have received far less attention than H5 or H7, H10Nx viruses have also shown a proclivity for spilling over into mammals (see Avian H10N7 Linked To Dead European Seals), and occasionally, infecting humans.
CHINA NHC Reports 1st Human H10N3 Avian Flu Infection - Jiangsu Province
HK CHP: A Cryptic Report of A 2nd H10N3 Case On the Mainland
Cell Host & MIcrobe: Avian H10N7 Adaptation In Harbor Seals
Jiangxi Province Reports 3rd H10N8 Case
Today the ECDC's weekly CDTR carried a synopsis of a preprint - published a few days ago in Nature Portflio - that describes the third known human infection with H10N3, which was detected in early March in Yunnan province. Their risk assessment follows:
Sporadic human cases of avian influenza A(H10N3) have been observed, but no human-to-human transmission has been documented. The risk to human health in the EU/EEA is considered very low. Direct contact with infected birds or contaminated environments is the most likely source of human infection with avian influenza. The use of personal protective measures for people exposed to sick or dead birds and their droppings will reduce the associated risk of infection.
The first two reported cases were in East-Central China (Jiangsu & Zhejiang Provinces). This is the first case in Southwest China. First, some excerpts from the preprint, which reports potentially significant mutations.
Follow the link to read it in its entirety.
First human case of avian influenza A (H10N3) in Southwest China
Guiming Liu, Jingyi Dai, Jun Zhao, Jiawei Xia, Pei Zhang, Yadi Ding, and 5 more
This is a preprint; it has not been peer reviewed by a journal.
https://doi.org/10.21203/rs.3.rs-4181286/v1
This work is licensed under a CC BY 4.0 License
. . . . a previously healthy 51-year-old male, presented with recurrent fever peaking at 39℃, accompanied by symptoms such as cough, expectoration, chest tightness, and shortness of breath. Diagnosis revealed severe pneumonia, type I respiratory failure, and infection with avian influenza virus H10N3. Additionally, the patient experienced complications from Candida albicans and Staphylococcus epidermidis infections. Following treatment with appropriate antiviral drugs and antibiotics, the patient's condition improved. Molecular analysis of the viral strain identified four mutations potentially hazardous to human health. This underscores the importance of continuous and vigilant monitoring of the dynamics surrounding the H10N3 subtype of avian influenza virus.
(SNIP)
On March 6, 2024 the patient went to Kunming Third People's Hospital for treatment due to continuous fever for many days, and was diagnosed with severe pneumonia, type I respiratory failure and infection by avian influenza virus. After the diagnosis of avian influenza virus infection, the patient investigated by using questionnaires, including demographic information, poultry contact history, basic diseases, etc.
(SNIP)
The symptoms observed in the patient infected with H10N3 in this case closely resemble those documented in the two previously known cases of H10N3 infection. Notably, all cases resulted in severe pneumonia in the affected patients8,9. In light of our findings, the identification of HA-Q226L, PB2-D701N, PA-S409N, and M2-S31N mutations in the protein of the Yunnan H10N3 virus strain underscores the potential for increased harm posed by H10N3 in humans. Therefore, it is imperative to closely monitor the dynamics of this subtype.
The case of human infection with H10N3 avian influenza virus highlighted in this study involved close contact with live birds, particularly through the handling and slaughtering of dead birds. This contact ultimately led to the patient contracting avian influenza and experiencing severe illness. This underscores the importance of paying special attention to instances of unexpected bird deaths and promptly reporting such cases.
Moreover, it emphasizes the necessity of establishing a comprehensive avian influenza surveillance system, not only within Yunnan but also globally, to continuously and vigilantly monitor the H10N3 virus strain and its potential impact on human health.
A little over 2 months ago, we looked at a study in The Lancet Microbe: Novel H10N3 Avian Influenza Viruses - a Potential Threat to Public Health, on the zoonotic potential of H10N3 viruses in China.
They report finding at least 15 genotypes - all with internal genes derived from the H9N2 virus - multiple AA mammalian adaptations - and a high binding affinity to α2,6 receptor cells, which are abundant in the human upper respiratory system.
Although the number of reported H10 infected humans remains small - possibly due to a lack of surveillance and testing - in 2014's BMC: H10N8 Antibodies In Animal Workers – Guangdong Province, China, we saw evidence that some people may have been infected with the H10N8 virus in China long before the first case was recognized.
A reminder that nature's laboratory is open 24/7, and while we focus on one threat, there may be others in the queue.