Do face masks scale back publicity to swine flu?

2 December 2024

4 minute learn

Editors observe: Because of the ongoing extremely pathogenic avian influenza outbreak within the US that has brought about infections in poultry and dairy farm employees, this research from the pork trade appears very related throughout species. The next is from a presentation by Joaquin Alvarez-Norambuena and colleagues, College of Minnesota, throughout the 2024 Leman Swine Convention. 

Influenza A virus (IAV) transmission between pigs and swine farm employees is a threat to public well being. Farm employees can get uncovered to IAV by direct contact with contaminated animals and not directly by touching contaminated surfaces and respiratory infectious aerosols containing virus-laden particles.

Private protecting gear consisting of face masks can be utilized to lower the chance of publicity to aerosols. Among the face masks that farm employees can use to guard themselves embody N95 respirators, mud masks, and surgical masks. Nevertheless, the comfort and stage of safety these face masks supply differ significantly amongst them.

A research evaluated and quantified the discount of IAV publicity by the varied face masks in farm employees. Finally, this research aimed to validate intervention methods to lower influenza transmission on the interface of pigs and folks.

Twenty-four swine employees from three Midwestern farms had been enrolled within the research. The chosen farms had confirmed an infection of IAV within the pigs. Participation of employees within the research was voluntary and contributors might drop from the research at any time.

Staff had been requested to put on one among three masks on a given day which included an N95 masks, mud masks, or surgical masks. Staff had been additionally requested to not put on a masks as a part of one of many therapies. Every employee wore every masks kind for a complete of 5 days. Every participant was requested to self-collect a nasal swab pattern earlier than sporting the face masks firstly of the workday. Then, employees wore the assigned face masks for a minimum of 2 hours every day. After that, employees eliminated their face masks and self-collected one other nasal swab.

A complete of 79 out of 832 (9.50%) samples examined RT-PCR optimistic for IAV. Twenty-eight out of 416 (6.73%) samples collected earlier than utilizing the face masks examined optimistic whereas 51 out of 416 (12.26%) examined optimistic after sporting masks. 

The present research supplies proof that utilizing face masks decreases the extent of publicity to IAV in swine farm employees. The outcomes add to the proof that IAV publicity in swine farms is frequent, and utilization of facemasks needs to be thought of as one of many methods to lower the chance of an infection on the human/animal interface.

This work was funded by the Nationwide Pork Board.

Airborne influenza A

The next is from a presentation by Juan Mena-Vásquez and colleagues, College of Minnesota, throughout the 2024 Leman Swine Convention.

Staff in swine amenities are liable to publicity to IAV. Swine IAV has been detected in air samples below each experimental and area situations. Nevertheless, the focus, dimension, and infectivity of airborne IAV-containing particles in swine amenities are poorly understood. Airborne transmission represents a crucial hole in biosecurity measures, enjoying a key function in each animal illness containment and zoonotic illness transmission.

A research assessed airborne focus, dimension, and infectivity of IAV-laden particles in swine amenities. 4 grow-to-finish swine farms (F1 to F4) within the Midwestern U.S. had been chosen based mostly on their historical past of IAV an infection. Two visits per farm had been performed within the winter and spring of 2024. Pig nasal wipes and air samples had been collected from one barn at every farm. Nasal wipes from pigs in ten pens (5 pigs per pen) had been sampled to substantiate IAV standing throughout every go to.

The non-viable Andersen cascade impactor (ACI) was used to measure IAV airborne focus and the scale of related airborne particles. The ACI sampler separates particles into 9 aerodynamic dimension intervals simulating the human respiratory tract and diploma of penetration by these particles. Three samples had been collected for half-hour per pattern, at a stream price of 28.3 L/min throughout every go to.

In the course of the first go to, pigs in all 4 farms examined optimistic for IAV, with nasal wipe samples having excessive Ct values starting from 34.4 to 37.5. In the course of the second go to, solely pigs in F1 and F4 examined optimistic for IAV and had decrease Ct values (28.8 and 28.7, respectively), indicative of a extra acute an infection in comparison with go to 1.

Sizing of virus laden particles in F1 resulted in optimistic leads to particles bigger than 2.1µm with concentrations starting from 6.3×105 to eight.9×106 RNA copies/m³, whereas in F4, optimistic samples had been obtained in particles bigger than 3.3µm with ranges between 4.7 x105 and a pair of.0x106 RNA copies/m³.