Airborne transmission may have played a role in the spread of 2015 highly pathogenic avian influenza outbreaks in the United States

Abstract

The unprecedented 2015 outbreaks of highly pathogenic avian influenza (HPAI) H5N2 in the U.S. devastated its poultry industry and resulted in over $3 billion economic impacts. Today HPAI continues eroding poultry operations and disrupting animal protein supply chains around the world. Anecdotal evidence in 2015 suggested that in some cases the AI virus was aerially introduced into poultry houses, as abnormal bird mortality started near air inlets of the infected houses. This study modeled air movement trajectories and virus concentrations that were used to assess the probability or risk of airborne transmission for the 77 HPAI cases in Iowa. The results show that majority of the positive cases in Iowa might have received airborne virus, carried by fine particulate matter, from infected farms within the state (i.e., intrastate) and infected farms from the neighboring states (i.e., interstate). The modeled airborne virus concentrations at the Iowa recipient sites never exceeded the minimal infective doses for poultry; however, the continuous exposure might have increased airborne infection risks. In the worst-case scenario (i.e., maximum virus shedding rate, highest emission rate, and longest half-life), 33 Iowa cases had > 10% (three cases > 50%) infection probability, indicating a medium to high risk of airborne transmission for these cases. Probability of airborne HPAI infection could be affected by farm type, flock size, and distance to previously infected farms; and more importantly, it can be markedly reduced by swift depopulation and inlet air filtration. The research results provide insights into the risk of airborne transmission of HPAI virus via fine dust particles and the importance of preventative and containment strategies such as air filtration and quick depopulation of infected flocks.

SARS-Cov-2 RNA Found on Particulate Matter of Bergamo in Northern Italy: First Preliminary Evidence

“…In previous communications, we have hypothesized the possibility that SARS-CoV-2 virus could be present on particulate matter (PM) during the spreading of the infection, [5,6] consistently with evidence already available for other viruses [7][8][9][10][11][12][13][14][15]. However, the issue of airborne PM-associated microbiome, especially in urban environments, remains largely under-investigated [16], and -at the presentnobody has still carried out experimental studies specifically aimed at confirming or excluding the presence of the SARS-CoV-2 on PM.…”

The Potential role of Particulate Matter in the Spreading of COVID-19 in Northern Italy: First Evidence-based Research Hypotheses

“…Based on the available literature [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], there is enough evidence to consider the airborne route, ant specifically the role of particulate matter, as a possible additional infection "boosting" factor for interpreting the anomalous COVID-19 outbreaks observed in the Northern Italy -known to be one of the European areas characterized by the highest PM concentration [1]. Airborne transmission is certainly more effective in indoor environments, with little ventilation, but it must be considered that the Po Valley, by its atmospheric stability, closely resembles a confined environment and that long-distance virus transport is favored by high concentration of dusts.…”

“…At the same time, a number of studies have shown that airborne transmission route could spread viruses even further the close contact with infected people [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Paules et al (2020) highlighted that -besides close distance contacts -airborne transmission of SARS-CoV can also occur [5].…”

“…Other recent studies have also reported associations between PM and infectious diseases (e.g., influenza, hemorrhagic fever with renal syndrome): inhalation could bring PM deep into the lung and virus attached to particles may invade the lower part of respiratory tract directly, thus enhancing the induction of infections, as demonstrated by Sedlmaier et al (2009) [12]. Zhao et al (2018) showed that the majority of the positive cases of highly pathogenic avian influenza (HPAI) H5N2 in Iowa (USA) in 2015 might have received airborne virus, carried by fine PM, from infected farms both within the same State and from neighboring States [13]. The condensation and stabilization of the bioaerosol, generating aggregates with atmospheric particles from primary (i.e.…”

Airborne Transmission Route of COVID-19: Why 2 Meters/6 Feet of Inter-Personal Distance Could Not Be Enough

“…Ambient influenza A virus spread was shown to be promoted during the Asian dust days when dust particles levels were significantly higher than during the average days [21]. Another relevant case was the H5N2 avian influenza diffusion across the USA in 2015, from Iowa to the neighbour states, attributed to the transboundary spread of airborne virus carried by fine PM [22]. The long-range transport of airborne bacteria and viruses was associated with the formation of aggregates with both primary and secondary particles.…”