Viral evolutionViral evolution is a subfield of evolutionary biology and virology that is specifically concerned with the evolution of viruses. Viruses have short generation times, and many—in particular RNA viruses—have relatively high mutation rates (on the order of one point mutation or more per genome per round of replication). Although most viral mutations confer no benefit and often even prove deleterious to viruses, the rapid rate of viral mutation combined with natural selection allows viruses to quickly adapt to changes in their host environment.
Fecal–oral routeThe fecal–oral route (also called the oral–fecal route or orofecal route) describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal–oral disease transmission include lack of adequate sanitation (leading to open defecation), and poor hygiene practices. If soil or water bodies are polluted with fecal material, humans can be infected with waterborne diseases or soil-transmitted diseases.
Child mortalityChild mortality is the mortality of children under the age of five. The child mortality rate (also under-five mortality rate) refers to the probability of dying between birth and exactly five years of age expressed per 1,000 live births. It encompasses neonatal mortality and infant mortality (the probability of death in the first year of life). Reduction of child mortality is reflected in several of the United Nations' Sustainable Development Goals. Target 3.
NorovirusNorovirus, sometimes referred to as the winter vomiting disease, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within one to three days. Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems. The virus is usually spread by the fecal–oral route.
Women migrant workers from developing countriesWomen migrant workers from developing countries engage in paid employment in countries where they are not citizens. While women have traditionally been considered companions to their husbands in the migratory process, most adult migrant women today are employed in their own right. In 2017, of the 168 million migrant workers, over 68 million were women. The increase in proportion of women migrant workers since the early twentieth century is often referred to as the "feminization of migration".
Case fatality rateIn epidemiology, case fatality rate (CFR) – or sometimes more accurately case-fatality risk – is the proportion of people diagnosed with a certain disease, who end up dying of it. Unlike a disease's mortality rate, the CFR does not take into account the time period between disease onset and death. A CFR is generally expressed as a percentage. It represents a measure of disease lethality and may change with different treatments. CFRs are most often used for with discrete, limited-time courses, such as acute infections.
