Microbes Cause Different Kinds of Infections
Some disease-causing microbes can make you very sick quickly and then not bother you again. Some can last for a long time and continue to damage tissues. Others can last forever, but you won ’t feel sick anymore, or you will feel sick only once in a while. Most infections caused by microbes fall into three major groups :
- Acute infections
- Chronic infections
- Latent infections
Acute infections are usually severe and last a short time. They can make you feel very uncomfortable, with signs and symptoms such as tiredness,achiness,coughing,and
sneezing. The common cold is such an infection. The signs and symptoms of a cold can last for 2 to 24 days (but usually a week),though it may seem like a lot longer. Once your body ’s immune system has successfully fought off one of the many different types of rhinoviruses or other viruses that may have caused your cold, the cold doesn ’t come back. If you get another cold, it ’s probably because you have been infected with other cold-causing viruses.
Chronic infections usually develop from acute infections and can last for days to months to a lifetime. Sometimes people are unaware they are infected but still may be able to transmit the germ to others. For example, hepatitis C, which affects the liver, is a chronic viral infection. In fact, most people who have been infected with the hepatitis C virus don ’t know it until they have a blood test that shows antibodies to the virus. Recovery from this infection is rare —about 85 percent of infected persons become chronic carriers of the virus. In addition, serious signs of liver damage, like cirrhosis or cancer, may not appear until as long as 20 years after the infection began.
THE DIFFERENCE BETWEEN INFECTION AND DISEASE
A disease occurs when cells or molecules in your body stop working properly, causing symptoms of illness.Many things can cause a disease, including altered genes,chemicals,aging,and infections. An infection occurs when a microbe —such as a virus, bacterium,fungus,or parasite —enters your body and begins to reproduce. The invading microbe can directly damage cells,or the immune system can cause symptoms,such as fever,as it tries to rid your body of the invader.Some infections do
not cause disease because the microbe is quickly killed or it remains dormant.
Latent infections are “hidden ” or “silent ” and may or may not cause symptoms again after the first acute episode.Some infectious microbes, usually viruses,can “wake up ”—become active again but not always causing symptoms —off and on for months or years. When these microbes are active in your body, you can transmit them to other people.Herpes simplex viruses, which cause genital herpes and cold sores, can remain latent in nerve cells for short or long periods of time, or forever. Chickenpox is another example of a latent infection. Before the chickenpox vaccine became available in the
1990s,most children got chickenpox. After the first acute episode, usually when children are very young, the Varicella zoster virus goes into hiding in the body. In many people, it emerges many years later when they are older adults and causes a painful disease of the nerves called herpes zoster, or shingles.
Researchers are studying what turns these microbial antics off and on and are looking for ways to finally stop the process.