Eco-Epidemiological Evidence of the Transmission of Avian and Human Influenza A Viruses in Wild Pigs in Campeche, Mexico

Abstract

Influenza, a zoonosis caused by various influenza A virus subtypes, affects a wide range of species, including humans. Pig cells express both sialyl-α-2,3-Gal and sialyl-α-2,6-Gal receptors, which make them susceptible to infection by avian and human viruses, respectively. To date, it is not known whether wild pigs in Mexico are affected by influenza virus subtypes, nor whether this would make them a potential risk of influenza transmission to humans. In this work, 61 hogs from two municipalities in Campeche, Mexico, were sampled. Hemagglutination inhibition assays were performed in 61 serum samples, and positive results were found for human H1N1 (11.47%), swine H1N1 (8.19%), and avian H5N2 (1.63%) virus variants. qRT-PCR assays were performed on the nasal swab, tracheal, and lung samples, and 19.67% of all hogs were positive to these assays. An avian H5N2 virus, first reported in 1994, was identified by sequencing. Our results demonstrate that wild pigs are participating in the exposure, transmission, maintenance, and possible diversification of influenza viruses in fragmented habitats, highlighting the synanthropic behavior of this species, which has been poorly studied in Mexico.

Influenza A and D Viruses in Non-Human Mammalian Hosts in Africa: A Systematic Review and Meta-Analysis

“…The results of the meta-analysis showed an estimated pooled prevalence of 1.6% (95% CI: 0-5%) of IAV in pigs in Africa. This finding is comparable to a study in Cambodia which reported a prevalence of 1.5% of IAV in pigs [97] but lower than the 11.7-15.7% and 19.67% reported in Guatemala [98] and Mexico [99], respectively. Further, the meta-analysis demonstrated an estimated pooled seroprevalence of 14.9% of IAV in pigs in Africa.…”

Heparan Sulfate and Sialic Acid in Viral Attachment: Two Sides of the Same Coin?

“…Influenza viruses (IAVs) are enveloped viruses with a negative-sense single-stranded RNA genome that belong to the Orthomyxoviridae family, which includes the influenza A, B, C, and D genera. Influenza A is the most virulent type for humans and is a zoonotic disease that affects a large number of species [ 59 , 60 ]. Therefore, this review will focus on the influenza A virus (IAV) only.…”

Avian Influenza A Virus Associations in Wild, Terrestrial Mammals: A Review of Potential Synanthropic Vectors to Poultry Facilities

“…Hong Kong [20] "Sewage rats" Presumably Rattus sp. Egypt [21] House mouse Mus musculus U.S. [4] Transbaikal hamster b Cricetulus pseudogriseus Russia [16] Campbell's dwarf hamster b Phodopus campbelli Russia [16] Brandt's vole Lasiopodomys brandtii Russia [16] Mongolian gerbil Meriones unguiculatus Russia [16] Daurian souslik Spermophilus dauricus Russia [16] Raccoon Procyon lotor U.S. [22] Japan [23,24] Arctic fox Vulpes lagopus U.S. [25] "Fox" c Not listed China [26] Black-backed jackal Canis mesomelas Namibia [17] Raccoon dog c Nyctereutes procyonoides China [26] Far-eastern wild cat Prionailurus bengalensis euptilurus Russia [27] Leopard cat Prionailurus bengalensis Korea [28] American mink Neovison vison Spain [38] Water deer Hydropotes inermis Korea [28] Feral swine Sus scrofa U.S. [30] Mexico [31] a This table is not intended to be an exhaustive list of all wild mammal exposures to influenza A viruses (IAV), as the focus of this paper is mammalian synanthropes. Some additional non-synanthropic species are listed in the text to bring attention to IAV exposures in select taxa.…”

“…In the U.S., researchers recently reported that although U.S. feral swine were predominantly exposed to swine IAVs, they may have also been exposed of avian IAVs on a less frequent basis [30]. Based on a relatively small sample size (n = 61), one feral swine in Mexico was assessed to be positive for antibodies reactive with an H5N2 virus that was presumed to be avian in origin [31]. In China, however, a small number of feral swine were reported to have been exposed to typical swine viruses (e.g., H1 and H3), but did not react to select avian viruses (e.g., H5 and H9) [48].…”

“…An IAV survey of feral and domesticated swine was recently reported from Mexico. While multiple swine were assessed to be positive for viral RNA from IAVs of various origins, a single feral pig was positive for a virus described as Feral Swine/Campeche/DMZD-DEFSAL-UIFMVZ19-12 (H5N2) [31]. Although phylogenetic analyses indicated that this virus was in the same clade as both avian and swine viruses, the authors suggested that the virus they sequenced was avian-origin [31].…”