Antibiotic resistance

Use or misuse of antibiotics may result in the development of antibiotic resistance by the infecting organisms, similar to the development of pesticide resistance in insects. Evolutionary theory of genetic selection requires that as close as possible to 100% of the infecting organisms be killed off to avoid selection of resistance; if a small subset of the population survives the treatment and is allowed to multiply, the average susceptibility of this new population to the compound will be much less than that of the original population, since they have descended from those few organisms which survived the original treatment. This survival often results from an inheritable resistance to the compound which was infrequent in the original population but is now much more frequent in the descendants thus selected entirely from those originally infrequent resistant organisms.

Antibiotic resistance has become a serious problem in both the developed and underdeveloped nations. By 1984 half of the people with active tuberculosis in the United States had a strain that resisted at least one antibiotic. In certain settings, such as hospitals and some child-care locations, the rate of antibiotic resistance is so high that the normal, low cost antibiotics are virtually useless for treatment of frequently seen infections. This leads to more frequent use of newer and more expensive compounds, which in turn leads inexorably to the rise of resistance to those drugs, and a never-ending ever-spiraling race to discover new and different antibiotics ensues, just to keep us from losing ground in the battle against infection. The fear is that we will eventually fail to keep up in this race, and the time when people did not fear life-threatening bacterial infections will be just a memory of a golden era.

Vaccines

A vaccine is an antigenic preparation used to produce active immunity to a disease, in order to prevent or ameliorate the effects of infection by any natural or "wild" strain of the organism. The term derives from Edward Jenner's use of cowpox ("vacca" means cow in Latin), which, when administered to humans, provided them protection against smallpox, which Pasteur and others perpetuated. The process of distributing and administrating vaccines is referred to as vaccination.

Vaccines against cancer are also being investigated. In this case, the antigenic preparation is derived from the cancer cell. There is also research on an HIV vaccine.

Origin of vaccines

Smallpox is the first disease people tried to prevent by purposely inoculating themselves with other types of infections. Inoculation is believed to have started in India or China before 200 BC. Physicians in China immunized patients by picking off pieces from drying pustules of a person suffering from a mild case of smallpox, grinding the scales to a powdery substance, and then inserting the powder into the person's nose in order for them to be immunized. In 1718, Lady Mary Wortley Montague reported that the Turks have a habit of deliberately inoculating themselves with fluid taken from mild cases of smallpox. Lady Montague inoculated her own children in this manner. In 1796, during the heyday of the smallpox virus in Europe, an English country doctor, Edward Jenner, observed that milkmaids would sometimes catch cowpox from dairy cows and were generally said to not then be able to catch smallpox. Cowpox is a mild relative of the deadly smallpox virus. Building on the foundational practice of inoculation, Jenner took infectious fluid from the hand of milkmaid Sarah Nelmes. He inserted this fluid, by scratching or injection, into the arm of a healthy local eight year old boy, James Phipps. Phipps then showed symptoms of cowpox infection. Forty-eight days later, after Phipps had fully recovered from cowpox, Jenner injected some smallpox-infected matter into Phipps, but Phipps did not later show signs of smallpox infection.