The Norovirus (common Sick Bug)

Norovirus (the winter vomiting bug) is a leading cause of stomach bugs in the UK, with an estimated 600,000 - 1 million people infected annually. There are at least 25 strains infectious to humans due to genetic variation. (NHS Website, 2014, p. Introduction). It is microscopic, acid resistant and contains a fragment of single stranded RNA protected by a protein capsid covered in specific antigens. They need human cells to reproduce as outside of a cell they`re unable to multiply, rendering them inactive.

Norovirus enters the body via the digestive tract through being ingested. Once inside the body it attacks the intestines and inserts its genetic material into intestinal cells. This causes the cell to produce numerous copies of the virus, that when fully-sized emerge (sometimes killing the host cell) and proceed to infect other cells.

In response the immune system releases white blood cells (lymphocytes and phagocytes). Lymphocytes create antibodies that match specific virus antigens. After multiplying, a stream of specific antibodies are released that attach to the virus. Phagocytes recognise these antibodies and proceed to destroy the attached virus. Antibodies will remain in the blood to prevent future reinfection.

Norovirus is transmittable through contact with infected faeces or vomit and is easily spread through contaminating surfaces or handling food by those infected. It is contagious and outbreaks in closed communities such as care homes, are common with viruses surviving on surfaces for several days. There is no treatment and symptoms usually develop after the incubation period of between 24 - 48 hours. Staying hydrated, eating easily digestible foods like soup and taking painkillers for aches and pains may help ease symptoms. The transmission of the virus can be prevented by washing hands and disinfecting surfaces frequently. Food preparation and close contact with others should be avoided for at least 48 hours after the symptoms disappear. (NHS Website, 2014, p. Introduction).

"In the 1930s, it was noticed that human viruses grown inside fertilised hens' eggs for several cycles tended to lose their virulence in humans, as they became adapted to growing inside the cells of a bird" (Cockell and Brown, 2009, p. 124-125). Vaccinations take roughly two weeks to become fully effective and when injected can give our immune system a chance to encounter inactive or less virulent viruses and create the appropriate antibodies needed. Some who have weaker immune systems like the elderly, may benefit from this.