Forty or fifty years ago, thanks to antibiotics, scientists thought medicine had all but eradicated infectious agents as a major health threat. Instead, the past two decades have seen an alarming resurgence of infectious diseases and the appearance of new ones.
Today, the AIDS virus, tuberculosis, malaria, diarrheal diseases and other infectious agents pose far greater hazards to human existence than any other creatures.
This upsurge of infectious disease is a problem we have unwittingly created for ourselves. The rise of rapid, frequent, and relatively cheap international travel allows diseases to leap from continent to continent. Inadequate sanitation and lack of clean drinking water are another factor. A third is the “antibiotic paradox” — the overuse of the “miracle drugs” to the point that they lose their potency.
Whenever antibiotics wage war on microorganisms, a few of the enemy are able to survive the drug. Because microbes are always mutating, some random mutation eventually will protect against the drug. Antibiotics used only when needed and as directed usually overwhelm the bugs. Too much antibiotic use selects for more resistant mutants. When patients cut short the full course of drugs, the resistant strains have a chance to multiply and spread.
In some countries, such as the United States, patients expect and demand antibiotics from doctors, even in situations where they are inappropriate or ineffective. Our immune systems will cure many minor bacterial infections on their own, if given the chance, and antibiotics have no effect on viral infections at all. Every time antibiotics are used unnecessarily, they add to the selective pressure we are putting on microbes to evolve resistance. Then, when we really need antibiotics, they are less effective.
While drug companies race to develop new antibiotics that kill resistant microbes, scientists are urging patients and doctors to limit antibiotic use.
Antibiotic use in livestock is the use of antibiotics for any purpose in the husbandry of livestock, which includes not only the treatment or prophylaxis of infection but also the use of subtherapeutic doses in animal feed to promote growth and improve feed efficiency in contemporary intensive animal farming. Antimicrobials (including antibiotics and antifungals) and other drugs are used by veterinarians and livestock owners to increase the size of livestock, poultry, and other farmed animals. The use of some drugs is banned in some countries due to food contamination or concern about increasing antibiotic resistance and what some consider antibiotic misuse. Other drugs may be used only under strict limits, and some organizations and authorities seek to further restrict the use of some or all drugs in animals. Other authorities, such as the World Organization for Animal Health, say that concerns for bacterial resistance in humans is overblown and restricting the availability of medicine is detrimental to animal health and the economical production of food.