Age-related decline in immune function takes sheep to the grave earlier

September 19, 2019

For the sheep of St. Kilda, growing old brings with it a late-life decline in immune resistance against pervasive parasitic worms, which greatly reduces the animal's chances of surviving overwinter, regardless of overall physiological condition. The study's findings, which compiled the life histories of hundreds of wild sheep into a 26-year record of life and death, offer new insight into the little-understood role of immunosenescence in the wild. How and why we age remains a perennial mystery in life sciences, and much of what we know about immunosenescence - the steady deterioration of immune function with age - is largely derived from human populations and laboratory rodent models. While it's thought that this process also plays a role in shaping the morbidity and mortality of natural populations, particularly as it relates to parasite infections, the large-scale longitudinal datasets required to evaluate such questions are lacking. However, according to Hannah Froy and colleagues, the lifetime monitoring of the sheep on St. Kilda provided the unique opportunity to study the interactions of immune function, parasite burden, health and mortality. Froy et al compiled the fates of 800 individual animals, each facing natural aging and infection pressures. The authors discovered that individual aged sheep showed a decline in the availability of an antibody associated with protection against helminth parasite infection, which predicted mortality risk in the wild and their probability of surviving the winter. "[Froy et al.'s] results unambiguously demonstrate that long-term studies are not only essential to answer major ecological and evolutionary questions but also provide an invaluable resource to address topical scientific questions from the entire life science spectrum," writes Jean-Michel Gaillard and Jean-Francois Lemaitre in a related Perspective.

American Association for the Advancement of Science

Related Mortality Articles from Brightsurf:

Being in treatment with statins reduces COVID-19 mortality by 22% to 25%
A research by the Universitat Rovira i Virgili (URV) and Pere Virgili Institut (IISPV) led by LluĂ­s Masana has found that people who are being treated with statins have a 22% to 25% lower risk of dying from COVID-19.

Mortality rate higher for US rural residents
A recent study by Syracuse University sociology professor Shannon Monnat shows that mortality rates are higher for U.S. working-age residents who live in rural areas instead of metro areas, and the gap is getting wider.

COVID-19, excess all-cause mortality in US, 18 comparison countries
COVID-19 deaths and excess all-cause mortality in the U.S. are compared with 18 countries with diverse COVID-19 responses in this study.

New analysis shows hydroxychloroquine does not lower mortality in COVID-19 patients, and is associated with increased mortality when combined with the antibiotic azithromycin
A new meta-analysis of published studies into the drug hydroxychloroquine shows that it does not lower mortality in COVID-19 patients, and using it combined with the antibiotic azithromycin is associated with a 27% increased mortality.

Hydroxychloroquine reduces in-hospital COVID-19 mortality
An Italian observational study contributes to the ongoing debate regarding the use of hydroxychloroquine in the current pandemic.

What's the best way to estimate and track COVID-19 mortality?
When used correctly, the symptomatic case fatality ratio (sCFR) and the infection fatality ratio (IFR) are better measures by which to monitor COVID-19 epidemics than the commonly reported case fatality ratio (CFR), according to a new study published this week in PLOS Medicine by Anthony Hauser of the University of Bern, Switzerland, and colleagues.

COVID-19: Bacteriophage could decrease mortality
Bacteriophage can reduce bacterial growth in the lungs, limiting fluid build-up.

COPD and smoking associated with higher COVID-19 mortality
Current smokers and people with chronic obstructive pulmonary disease (COPD) have an increased risk of severe complications and higher mortality with COVID-19 infection, according to a new study published May 11, 2020 in the open-access journal PLOS ONE by Jaber Alqahtani of University College London, UK, and colleagues.

Highest mortality risks for poor and unemployed
Large dataset shows that income, work status and education have a clear influence on mortality in Germany.

Addressing causes of mortality in Zambia
Despite the fact that people in sub-Saharan Africa are now living longer than they did two decades ago, their average life expectancy remains below that of the rest of the world population.

Read More: Mortality News and Mortality Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to