New research led by academics in the veterinary and medical schools at the University of Bristol in the U.K. used the "One Health" approach to study three bacterial species in the noses of young cattle and found that the carriage of the bacteria was surprisingly different.
The findings — combined ideas and methods from both animal and human health research — could help prevent and control respiratory diseases, the announcement said.
Cattle, like people, harbor a wide range of bacteria in their noses: microbes that are normally present and probably necessary for health, like those that live in the gut, the researchers said. However, some species of these bacteria do cause serious illness at times, particularly when infection becomes established in the lower respiratory tract within the lungs.
In an open-access paper published Aug. 16 in Scientific Reports, the researchers investigated the patterns of acquiring and clearing these microbes in healthy young cattle, which have not previously been studied in detail.
The research team took nasal swabs at intervals during the first year of life to detect the presence and measure the abundance of microbes using a DNA-detection technique called quantitative polymerase chain reaction (qPCR) that targeted genes found in three bacterial species well known for their ability to cause respiratory disease in cattle: Histophilus somni, Mannheimia haemolytica and Pasteurella multocida.
The researchers found that the carriage patterns of the three bacteria differed remarkably, the university said.
According to the researchers:
- Pasteurella was found in most of the animals -- usually in large numbers -- and the bacteria stayed in the nose for weeks or months.
- Histophilus was present in up to half the animals -- usually in smaller numbers -- and the periods it was present were shorter.
- Mannheimia was rarely found, although the numbers detected, when present, varied widely.
These differences are of interest because the numbers of bacteria and their duration of carriage are likely to influence their spread among healthy cattle and the likelihood of causing severe respiratory disease, the researchers said.
"These techniques and results offer a way forward in understanding why and how apparently healthy cattle harboring these bacteria may go on to develop respiratory illness and should help in finding new ways to prevent it," said Amy Thomas, lead author who carried out the research as part of her doctoral studies in clinical veterinary science at the University of Bristol.
Professor Mark Eisler, co-author and chair in Global Farm Animal Health at the Bristol Vet School, added, "These studies are particularly important because cattle are known to contribute to greenhouse gas emissions, and improving how their diseases are controlled will help mitigate climate change. Also, reducing the use of antimicrobials that treat respiratory diseases in cattle should help reduce the increasing global threat of antimicrobial resistance in animals and humans."