Food borne illness or food poisoning is caused by consuming food contaminated with pathogenic bacteria, toxins, viruses, prions or parasites. Such contamination usually arises from improper handling, preparation or storage of food. Food borne illness can also be caused by adding pesticides or medicines to food, or consuming or by accidentally consuming naturally poisonous substances like poisonous mushrooms or reef fish. Contact between food and pests, especially flies, rodents and cockroaches, is a further cause of contamination of food.
Some common diseases are occasionally food borne mainly through the water vector, even though they are usually transmitted by other routes. These include infections caused by Shigella, Hepatitis A, and the parasites Giardia lamblia and Cryptosporidium parvum.
World Health Organization definition
Food borne illnesses are defined by the World Health Organization as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. Every person is at risk of food borne illness
Symptoms and mortality
Symptoms typically begin several hours after ingestion and depending on the agent involved, can include one or more of the following: nausea, abdominal pain, vomiting, diarrhea, fever, headache or tiredness. In most cases the body is able to permanently recover after a short period of acute discomfort and illness. However, food borne illness can result in permanent health problems or even death, especially in babies, pregnant women (and their fetuses), elderly people, sick people and others with weak immune systems. Similarly, people with liver disease are especially susceptible to infections from Vibrio vulnificus, which can be found in oysters.
The delay between consumption of a contaminated food and appearance of the first symptoms of illness is called the incubation period. This ranges from hours to days (and rarely years), depending on the agent, and on how much was consumed.
During the incubation period, microbes pass through the stomach into the intestine, attach to the cells lining the intestinal walls, and begin to multiply there. Some types of microbes stay in the intestine, some produce a toxin that is absorbed into the bloodstream, and some can directly invade the deeper body tissues. The symptoms produced depend on the type of microbe.
A brand name drug has to go through 10-15 years of research and testing in animals and people before it can be sold to the public.
During this testing, the company making the drug must prove that it is safe and effective for people to use. All of this testing can cost over $1 billion. Once the new drug is approved, the company that made and tested it receives a patent. This means that no other company can make the drug until the end of the patent, which is usually 10-15 years after the drug is released.
When a patent for a brand name drug expires, any other company can copy the drug and sell a generic version. These other companies must only prove that their product is the same as the brand name drug.
This means that generic drug companies do not have to spend as much time and money because they do not have to invent or test the drug for safety and get FDA-approval. This is why generic drugs cost less.
When a patent for a brand name drug expires, there are usually a number of companies that begin to make a generic version of the drug. Since there is more than one company making the drug, the price is lowered even farther due to competition between all of the different generic drug makers.
This is a very interesting and informative video produced by eye surgeon Dr. Dave Allenby. In it he explains and visually demonstrates the four primary reasons that people may need their vision corrected by glasses and/or surgery.