why do we need to know the category of infectious agent before deciding the mode of treatement
Answers
have existed in human society probably as long as sickness itself. However, with the advent of the modern pharmaceutical industry, biochemical approaches to preventing and treating disease have acquired a new level of prominence in the evolving relationship between microbes and their human hosts.
Vaccines
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe or its toxins. The agent stimulates the body’s immune system to recognize it as foreign, destroy it, and ”remember” it, so that the immune system can more easily identify and destroy any of these microorganisms that it encounters later. The body’s immune system responds to vaccines as if they contain an actual pathogen, even though the vaccine itself is not capable of causing disease. Because vaccines are widely used in the United States, many once-common diseases—polio, measles, diphtheria, whooping cough, mumps, tetanus, and certain forms of meningitis—are now rare or well controlled.
Vaccinated people produce antibodies that neutralize a disease-causing virus or bacterium. They are much less likely to become infected and transmit those germs to others. Even people who have not been vaccinated may be protected by the immunity of the “herd,” because the vaccinated people around them are not getting sick or transmitting the infection. The higher the proportion of vaccinated people in a community, the lower the likelihood that a susceptible person will come into contact with an infectious individual—leading to greater herd immunity.
In the past, thimerosal, a preservative that contains mercury, was used in some vaccines and other products. Use of this product became the subject of controversy, with some arguing that the substance caused autism in children. Extensive, independent research has presented no convincing evidence of harm associated with the low levels of thimerosal present in vaccines. Since 2001, thimerosal has not been routinely used as a preservative in recommended childhood vaccines.
Antibiotics and Antivirals
Antibiotics are powerful medicines that fight bacterial infections. They either kill bacteria or stop them from reproducing, allowing the body’s natural defenses to eliminate the pathogens. Used properly, antibiotics can save lives. But growing antibiotic resistance is curbing the effectiveness of these drugs. Taking an antibiotic as directed, even after symptoms disappear, is key to curing an infection and preventing the development of resistant bacteria.
Antibiotics don’t work against viral infections such as colds or the flu. In those cases, antiviral drugs, which fight infection either by inhibiting a virus’s ability to reproduce or by strengthening the body’s immune response to the infection, are used. There are several different classes of drugs in the antiviral family, and each is used for specific kinds of viral infections. (Unlike antibacterial drugs, which may cover a wide spectrum of pathogens, antiviral medications are used to treat a narrower range of organisms.) Antiviral drugs are now available to treat a number of viruses, including influenza, HIV, herpes, and hepatitis B. Like bacteria, viruses mutate over time and develop resistance to antiviral drugs.