Antigenicity and genetic #properties of an #Eurasian #avian-like #H1N1 swine #influenza virus in #Jiangsu Province, #China

Highlights

• Scientific question: Cross-species transmission of influenza A viruses from swine to humans occurs occasionally because their tracheal epitheliums possess both sialic acid α-2,6-Gal and α-2,3-Gal receptors. In 2011, the first human case of swine influenza virus infection in the mainland of China was detected in Jiangsu Province. Subsequently, the Eurasian avian-like H1N1 swine influenza virus (EAH1N1 SIV) had sporadically crossed the host barrier and infected humans, raising public concern for its pandemic potential.

• Evidence before this study: A/Jiangsu/1/2011 (H1N1v) was first discovered in 2011 and belongs to the G1 genotype. The G4 and G5 genotypes that appeared successively in 2013 are recombinant H1N1 swine influenza viruses. The EAH1N1 SIVs from 2016 to the present are dominated by the G4 genotype, with hemagglutination (HA) and neuraminidase (NA) genes derived from the EAH1N1 SIVs, non-structural protein (NS) genes derived from the triple-origin reassortant swine influenza viruses, and the rest of the internal genes from influenza A (H1N1) pdm09 virus.

• New findings: This study investigated a case of the EAH1N1 SIV infection in a child. This is the first case of the EAH1N1 SIV genotype G4 infection in a child in Jiangsu Province. This virus maintained the genetic properties of the EAH1N1 SIV but differed significantly in HA protein antigens.

• Significance of the study: This new human case of the EAH1N1 SIV infection indicates the pandemic potential of avian influenza viruses.

Abstract

Pigs are vital genetic mixing vessels for human and avian influenza viruses because their tracheal epitheliums possess both sialic acid α-2,6-Gal and α-2,3-Gal receptors. Cross-species transmission of influenza A viruses from swine to humans occurs occasionally. The first case of human infection with the Eurasian avian-like H1N1 swine influenza virus (EAH1N1 SIVs) genotype G4 was detected in Jiangsu Province, China, in February 2023, and backtracking epidemiological investigations did not reveal a clear source of the infection. The hemagglutination (HA) and neuraminidase (NA) amino acid variant sites, antiviral drug susceptibility, and antigenic variation of the isolated A/Jiangsu/27271/2023 (JS/27271/23) virus were analyzed, and we evaluated the protective effect of sera collected from occupationally exposed populations in 2024 against the virus. Compared with the vaccine strain, the nucleotide sequence similarities of JS/27271/23 HA and NA were 96.5 % and 95.2 %, respectively. JS/27271/23 was sensitive to polymerase inhibitors (favipiravir and baloxavir), and the antigenicity of its HA protein was 8-fold different from that of the vaccine strain. The percentage of occupationally exposed population with antibody titers of ≥ 40 against A/Hunan/42443/2015 (HN/42443/15) and A/Jiangsu/1/2011 (JS/1/11) were 7.25 % and 2.25 %, respectively, and the geometric mean titers (GMT) were 6.24 and 5.34, respectively. Out of 400 serum samples examined, none had antibody titers of ≥ 40 against JS/27271/23. This suggests that low serum levels of antibodies to EAH1N1 SIVs in occupationally exposed populations may not provide adequate protection because of significant differences in amino acid sites and antigenicity between this virus and the current vaccine strain of EAH1N1 SIVs. There is no evidence of human-to-human transmission of EAH1N1 SIVs. Therefore, surveillance for EAH1N1 SIVs and the development of new vaccine strains are required.

Source: Biosafety and Health, https://www.sciencedirect.com/science/article/pii/S2590053624001381?via%3Dihub

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#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...

Stability of #influenza viruses in the #milk of #cows and #sheep

Abstract In late 2023, H5N1 high pathogenicity avian influenza (HPAIV) started circulating in dairy cattle in the USA . High viral titres were detected in milk from infected cows , raising concerns about onwards human infections . Although pasteurisation was shown to effectively inactivate influenza viruses in milk, unpasteurised milk still poses a risk of infection, both from occupational exposure in dairies and from the consumption of raw milk. We therefore assessed how long influenza viruses could remain infectious for in milk without heat inactivation. We examined the stability of a panel of influenza viruses in milk , including a contemporary H5N1 HPAIV and a variety of other influenza A and D viruses. We incubated viruses in cows' milk under laboratory conditions : at room temperature to simulate exposure in dairies and at 4°C to simulate exposure to refrigerated raw milk. Following an isolated report of H5N1 viral RNA being detected in milk from a sheep in the UK , we also c...

#Evidence of #Viremia in Dairy #Cows Naturally Infected with #Influenza A {#H5N1} Virus, #California, #USA

Abstract We confirmed influenza A virus (IAV) by PCR in serum from 18 cows on 3 affected dairy farms in California, USA . Our findings indicate the presence of viremia and might help explain IAV transmission dynamics and shedding patterns in cows. An understanding of those dynamics could enable development of IAV mitigation strategies. Source: US Centers for Disease Control and Prevention, https://wwwnc.cdc.gov/eid/article/31/7/25-0134_article ____

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