The Southern Newsroom
| May 22, 2022
A study identified viruses in samples taken from cattle in Rio Grande do Sul. (Picture: Gustavo Diehl/Secom RS)
Conducted by UFRGS in partnership with Feevale University, research Bovine influenza D virus in Brazil differs from established lines showed that influenza D virus is already present in cattle in South America. Previously, the virus had only been identified in animals from North America, Europe and Asia.
Published in the Archives of Virology, the study checked ten samples from ruminants that exhibited respiratory disease and, in one of them, the virus was identified.
According to Cláudio Canal, a professor at the UFRGS Faculty of Veterinary Medicine who participated in the research, it was already suspected that the influenza D virus was circulating among cattle in Brazil. “We searched for a year, more or less, until we found an animal that had this virus.” The study could be the first step to investigate influenza D infections in cattle in Brazil and neighboring countries where the beef industry is economically important.
Unlike influenza A and B viruses, which affect humans and have been known to researchers for some time, influenza C and D viruses were discovered recently, about ten years ago. Although it was detected for the first time in pigs in the United States, today we know that the microorganism mainly infects cattle: Cláudio took part in an epidemiological study which, from serum samples cattle sampled in the United States in 2014 and 2015, found that 77.5% of animals had antibodies to the disease, indicating prior infection.
In Brazil, the first detection occurred when a rural producer approached Professor David Driemeier, also from the UFRGS Faculty of Veterinary Medicine, to diagnose cattle with respiratory problems. Samples – nasal swabs – were taken from these animals and sent to the lab. “Professor Driemeier contacted me, because I work with viruses, and I did a PCR test on these samples, and in one of them we detected the influenza D virus”, explains Cláudio .
The researchers then teamed up with Feevale University to characterize the genome (set of all the genes of a living being) of the virus, using high-performance sequencing equipment, also called next-generation sequencing. This process is used to detect living beings that are not yet known to science, as the professor explains: “It sequences all the nucleic acid, DNA and RNA of this sample. This way you can see what is different from what is normal to find in a human or animal. In the case of influenza D, we already knew that [o vírus] was in that sample, but we wanted to have its entire genome to know it in its entirety, not just a little piece that we had detected by PCR.”
“This powerful sequencing tool is very important today, just look at the case of covid-19 and all the new diseases that are being discovered. This technology was used to discover the agent, and viruses and bacteria were discovered that were not known before. This opened up a different world for medicinal biology.
The influenza D virus has already been detected in humans – antibodies have even been detected in cattle farmers, which demonstrates that the microorganism circulates in the human population. However, it is not yet clear whether influenza D is relevant enough to generate clinical signs in humans. “It is not yet known if the respiratory disease that the virus causes in humans is important. Apparently it is bland, but it is running out of time [de estudo]“, adds the professor.
In addition, viruses cause several diseases that lead to health damage and economic loss in production animals. According to a report by Embrapa – Empresa Brasileira de Pesquisa Agropecuária, in 2020 the Brazilian cattle herd was the largest in the world, with 217 million head, or 14.3% of the world herd. And the more animals raised in high concentrations, the easier it is for viruses to circulate between them, which can cause diseases that impact the country’s animal production. According to Cláudio, there is still a long way to go, the next steps include finding out if the influenza D virus causes disease in cattle and to what extent. In addition, it is also necessary to check whether it will be necessary to create a vaccine to prevent animals from getting sick.