Multiple sclerosisMultiple sclerosis (MS) is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Specific symptoms can include double vision, visual loss, muscle weakness, and trouble with sensation or coordination.
Risk factorIn epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Due to a lack of harmonization across disciplines, determinant, in its more widely accepted scientific meaning, is often used as a synonym. The main difference lies in the realm of practice: medicine (clinical practice) versus public health. As an example from clinical practice, low ingestion of dietary sources of vitamin C is a known risk factor for developing scurvy.
Spillover infectionSpillover infection, also known as pathogen spillover and spillover event, occurs when a reservoir population with a high pathogen prevalence comes into contact with a novel host population. The pathogen is transmitted from the reservoir population and may or may not be transmitted within the host population. Due to climate change and land use expansion, the risk of viral spillover is predicted to significantly increase. Spillover is a common event; in fact, more than two-thirds of human viruses are zoonotic.
Evolutionary landscapeAn evolutionary landscape is a metaphor or a construct used to think about and visualize the processes of evolution (e.g. natural selection and genetic drift) acting on a biological entity (e.g. a gene, protein, population, or species). This entity can be viewed as searching or moving through a search space. For example, the search space of a gene would be all possible nucleotide sequences. The search space is only part of an evolutionary landscape. The final component is the "y-axis", which is usually fitness.
Comparison of the healthcare systems in Canada and the United StatesA comparison of the healthcare systems in Canada and the United States is often made by government, public health and public policy analysts. The two countries had similar healthcare systems before Canada changed its system in the 1960s and 1970s. The United States spends much more money on healthcare than Canada, on both a per-capita basis and as a percentage of GDP. In 2006, per-capita spending for health care in Canada was US3,678;intheU.S.,US6,714. The U.S. spent 15.3% of GDP on healthcare in that year; Canada spent 10. MultimorbidityMultimorbidity, also known as multiple long-term conditions (MLTC), means living with two or more chronic illnesses. For example, a person could have diabetes, heart disease and depression at the same time. Multimorbidity can have a significant impact on people's health and wellbeing. It also poses a complex challenge to healthcare systems which are traditionally focused on individual diseases. Multiple long-term conditions are much more common in older people, affecting more than half of those over 65, however, they can also be found in young people.
Down syndromeDown syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. There are three types of Down syndrome, all with the same features: Trisomy 21, the most common type; Mosaic Down syndrome, and Translocation Down syndrome. The parents of the affected individual are usually genetically normal.
