Influenza at the animal–human interface: a review of the literature for virological evidence of human infection with swine or avian influenza viruses other than A(H5N1)

Abstract

Factors that trigger human infection with animal influenza virus progressing into a pandemic are poorly understood. Within a project developing an evidence-based risk assessment framework for influenza viruses in animals, we conducted a review of the literature for evidence of human infection with animal influenza viruses by diagnostic methods used. The review covering Medline, Embase, SciSearch and CabAbstracts yielded 6,955 articles, of which we retained 89; for influenza A(H5N1) and A(H7N9), the official case counts of the World Health Organization were used. An additional 30 studies were included by scanning the reference lists. Here, we present the findings for confirmed infections with virological evidence. We found reports of 1,419 naturally infected human cases, of which 648 were associated with avian influenza virus (AIV) A(H5N1), 375 with other AIV subtypes, and 396 with swine influenza virus (SIV). Human cases naturally infected with AIV spanned haemagglutinin subtypes H5, H6, H7, H9 and H10. SIV cases were associated with endemic SIV of H1 and H3 subtype descending from North American and Eurasian SIV lineages and various reassortants thereof. Direct exposure to birds or swine was the most likely source of infection for the cases with available information on exposure.

Comparison of chest-CT findings of Influenza virus-associated pneumonia in immunocompetent vs. immunocompromised patients

“…Subtypes occur only among the Influenza A viruses. Their differentiation is based on different antigenic properties of their hemagglutinin (H1-H16) and neuraminidase (N1-N9) glycoproteins [1,2]. At present the most common viruses are Influenza virus A of subtypes H1N1 and H3N2 and Influenzavirus B.…”

“…the world population contract Influenza virus infections every year [1,2]. Influenza viruses belong to the family Orthomyxoviridae, which are characterized by a segmented, negative-strand RNA genome.…”

A simplified Sanger sequencing method for full genome sequencing of multiple subtypes of human influenza A viruses

“…Most of the subtypes are found in avian, some in swine, human and other species such as bats. While H1N1 and H3N2 are the most common subtypes currently circulating in humans [6], there have also been sporadic cases of human infection with other influenza A subtypes in recent years [7], such as H5N1,H7N9, H10N7, H7N9 and H9N2, H6N1 [8][9][10][11][12][13][14][15].…”

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses

“…Since then, sporadic human infections by avian IAV of H5N1 and other HA subtypes have occurred with a fatality rate of close to 60% (Chen et al, 2014;Freidl et al, 2014;WHO report, 2014). Thus avian IAV, mainly of H5 and H7 subtypes, as well as originally swine, later human pandemic influenza A(H1N1) pdm09 virus with its avian ancestors, still pose a pandemic threat to humans (Hatta and Kawaoka, 2002;Subarrao et al, 2006;Garten et al, 2009).…”