Immune system becomes weaker as you age – everyone knows that.That is why older people are more susceptible to various bacterial and viral infections. But is is the same with animals? Scientists from the University of Edinburgh conducted a long-term study with a Scottish sheep breed and found out that we are not unique in this regard.
Soay sheep originates in Scotland and is still grown by many farmers in that area. However, despite it being domesticated, there are still wild Soay sheep in island of Soay in the St Kilda Archipelago, about 65 kilometres from the Western Isles of Scotland. That is where scientists went to conduct their long-term study into wild animal ageing and its effect on individual immunity.
Soay is the favorite sheep breed of Scottish farmers. Image credit: Lamiot via Wikimedia (CC BY-SA 3.0)
The long-term study of Soay sheep began in 1985. In the period between 1990 and 2015 more than 2,000 blood samples were taken from almost 800 animals across their lifetime. Animals are living wild in the St Kilda Archipelago and have been for hundreds of years. In fact, these islands are protected world heritage site, popular among tourists. For them Soay sheep are the highlight of the visit, even is many of them are not willing to stand close to tourists and pose for pictures.
Scientists found that just like humans, Soay sheep lose the strength of their immune systems as they age. In particular, their ability to deal with parasitic worms declines through adulthood. This process of declining immune system’s capabilities with age, called immunosenescence, is one of the challenges of modern day medicine, as it makes older generation suffer from more viral and bacterial infections.
Professor Dan Nussey, one of the authors of the study, said: “Our work provides the first evidence that deterioration in immune function in old age plays an important role in wild animal populations. It also provides rare clues from outside the laboratory that our ability to fight worm infection might fade as we age. Most studies of worm infections in humans focus on children and young adults in developing countries, with much less attention paid to older individuals”.
However, these results are not just important for humans. They are also crucial for farming. We need more efficient farming methods and maintaining animals healthy for longer. Scientists found that sheep with reduced immune system and parasitic infections were more likely not to survive the following winter. This is a very important piece of information for farmers.
These results are not that surprising. Human suffer from the effects of ageing and so why animals should be immune to them? They are not. As our immune systems deteriorate as we age, animals suffer from the same fate of time.
Source: University of Edinburgh