Examining the Environment to Identify Viruses in Livestock

 With the increased  reliance on livestock and animal products in today’s world, humans and animals are in closer proximity than ever. This closeness however, also makes this connection susceptible to be corrupted by the spread of viral disease. This spread from animals to humans is called zoonotic infection and is how many of the most serious viral outbreaks began such as influenza and coronavirus. Livestock are particularly vulnerable to the spreading of these viruses as they are often clustered close together, promoting viral transmission that can eventually make its way to human hosts. Resources for monitoring viruses within livestock populations have, however, been a challenge as traditional monitoring has had to be done directly on the animals which can pose risks to both the animals and the researchers. Thus, scientists are looking to develop new ways to surveil virus transmission in non-invasive ways.

One way researchers have looked to solve this problem is that rather than testing the animals themselves, they could look at samples of aggregated materials from many animals such as manure, air samples, and wastewater to track viruses within animal populations. Methods of monitoring pathogens from aggregated samples have already proven effective in some cases and researchers wanted to further test this theory to see if aggregate samples could appropriately serve as reliable indicators of virus transmission in  populations of cattle and pigs.

The researchers began by setting up sample collection sites at cow and pig farms in Barcelona as well as at several slaughterhouses. They collected 105 samples across eleven months between slurry, manure, wastewater, and air samples from the locations. The samples were separated into different pools based on whether they were from pigs or cows and by the season they were collected. Viruses were then extracted from each sample by slowly removing organic and biological particles from the sample until viral DNA could be isolated.

In the swine samples, the researchers found evidence of 56 total viral species and saw that the viruses seemed to have seasonal variation with each virus seeming to have a preferred peak season of high abundance that matches with known viral seasonality indicating a success of using aggregated samples to test for viruses.

The researchers then compared their findings with the samples taken at cattle farms and from cattle wastewater samples. They found that since cows are housed at a lower density than pigs, there was a sharp decrease in pathogen detection since viruses could not be passed as easily when the animals are farther apart. The researchers did however notice the same pattern of seasonality for the 63 viral species that appeared in their screens, many of which appeared in a specific sample type alone showing the best ways to monitor those specific viruses. 

Based on their results, the researchers conclude that an aggregated sample approach is an effective way to monitor animal viruses in livestock populations. Based on their results and their alignment with previous direct studies on viral presence in livestock populations, the authors believe that aggregate sampling could prove to be of significant use, especially in the prevention of zoonotic infections that could infect humans. While this method can make it difficult to determine which individuals in a population are infected due to the collection methods, the overall results from this study indicate that there are some new approaches coming to virus monitoring and the prevention of virus spread.

In order to be even more effective with these new techniques for virus monitoring, we could complement them through making advances in viral detection technology that might allow us to track viruses and their mutations so we can be even more prepared to face viral threats as they develop before they infect the larger population. We could also look into applying this technique to non-livestock animals which would help to prevent the spread of infection globally. This paper demonstrates a major shift coming for viral monitoring and detection which could ultimately lead help us to be safer and more prepared for emerging viral infections

Literature Cited:

Rusiñol, M., Martínez-Puchol, S., Ribeiro, D., Verdaguer, J., Torrejón-Llorens, O., Itarte, M., Estarlich-Landajo, I., Mejías-Molina, C., Juliachs-Torroella, G., Girones, R., Ramírez, G. A., Baliellas, J., Bofill-Mas, S., & Fernández-Cassi, X. (2026). Livestock aggregated samples for monitoring viruses infecting animals and potentially zoonotic viral pathogens. One health (Amsterdam, Netherlands), 22, 101340. https://doi.org/10.1016/j.onehlt.2026.101340

A Rabies-Based Vaccine? The Emerging Vaccination Landscape.

 Over the last couple of years, many scientists and epidemiologists have been watching the spread of a new virus, the H5N1 avian influenza. While initially developed in birds, there has just been a recent development where it has now begun to spread within populations of cattle, and even humans have now been infected. This new flu is extremely worrying as though the infected humans only seem to have mild symptoms, previous H5N1 epidemics have had severe mortality rates. Thus, scientists are currently looking for some possible vaccinations that work for humans and animals, should this virus become a major public threat.

One possible vaccine avenue that scientists are interested in studying is through the use of dual rabies virus vaccines or RABV that have been known to protect against other viral pathogens. To test this theory, a lab at Thomas Jefferson University developed a RABV-based H5 dual vaccine or RABV-H5 that has antigens which would protect against both the avian influenza as well as rabies virus. 

In order to develop this vaccine, the researchers inserted a synthesized version of the avian flu into the genetic sequence of rabies virus. The proper functioning of both parts of the new vaccine sequence were then analyzed and confirmed that the vaccine sequence had effective functioning of both viruses and that the influenza sequence had successfully integrated into the rabies virus sequence.

Figure 1A.

Now that the vaccine had been made, the researchers wanted to determine how effective this vaccine was. The researchers tested the vaccine on mice using different methods to vaccinate them. They used both an inactivated, or killed, form of the RABV-H5 as the vaccine as well as a live version of RABV-H5 and vaccinated the mice either with an injection in the muscle or by applying droplets of vaccine to the nose. 

Figure 1E.

After vaccination, the researchers looked for antibodies to the H5 which would serve as a sign that the vaccine worked and led to immunity of the virus. They found that in all cases, the mice had antibodies to H5 and found that vaccinating with a muscle injection at both the primary and secondary vaccination steps, the mice had higher antibody levels which indicates that these mice would have the strongest viral immunity.

After the success of the initial vaccination test, and following the same vaccination procedure paired with non-vaccinated control mice, mice were given a lethal dose of a mouse adapted version of the avian influenza virus. The researchers found that mice given the vaccine showed fewer signs of illness including weight loss and less virus seen on their lungs and had a much higher survival rate, including a one hundred percent chance of survival when given the vaccine intramuscularly both times or intramuscularly the first time and then a live version of the RABV-H5 vaccine delivered intranasally as a booster. This result stands in stark contrast to the mice that were unvaccinated and succumbed to the virus within six days, and even the mice that were vaccinated in alternate ways that only had a forty to sixty percent survival rate.

Seeing this success, the researchers did the exact same experiment, but this time with the authentic version of the avian influenza. Similar results followed from this experiment as vaccinated mice had a high survival rate and saw limited effects from the virus while unvaccinated mice succumbed to the virus at six to seven days.

With the success of the vaccine against both the mouse adapted version of the virus and the authentic virus itself, the researchers also wanted to look at how the vaccine would perform against a similar virus strain that is currently in circulation.  The researchers found that the vaccine did seem to have some effect as it reduced weight loss in the vaccinated mice and led to high survival rates against a reduced form of the virus, but as the researchers expected, the vaccine had no effect on the lethal dose of the virus.

This paper illustrates the wide world of vaccines and the unlikely places that they can come from. The use of vaccine platforms such as RABV to build new vaccines in quick order so as to prevent disease spread should not be underestimated as these platforms most likely hold the key to preventing the spreading of emerging viruses and combatting viruses before they become a major human concern. The virus created and tested in this paper also offers a glimpse at emerging vaccine technology such as the ability to vaccinate for multiple viruses with a single vaccine and also shows the increasing need to develop vaccines with both humans and animals in mind to prevent a virus from spreading from animals to humans.

While this study shows a lot of exciting potential for vaccines against new and emerging infectious diseases, this study leaves open the future possibilities of this vaccine as the next steps would be evaluating its effectiveness in humans after the successes seen in mice. While there may be future viral threats that could begin a new epidemic, this emerging vaccine technology could help us to prevent that from happening.

Literature Cited:

Paran, N., Wirblich, C., Albrecht, R., Zabihi-Diba, L., Tarquinio, A., Kurup, D., Solomides, C. C., García-Sastre, A., & Schnell, M. J. (2026). Immunogenicity and efficacy of a rabies-based vaccine against highly pathogenic influenza H5N1 virus. Emerging microbes & infections, 15(1), 2620221. https://doi.org/10.1080/22221751.2026.2620221