A cnidarian parasite of salmon (Myxozoa: Henneguya) lacks a mitochondrial genome (2020). Yahalomi D, et al

Not strictly health news, but an interesting development in understanding the role of mitochondria.

"The myxozoan cells retain structures deemed mitochondrion-related organelles, but have lost genes related to aerobic respiration and mitochondrial genome replication. Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals.

https://www.pnas.org/content/early/2020/02/18/1909907117