“I’m afraid to touch doorknobs in public places because of germs.”
“I won’t get vaccinated because what if my body can’t fight it and I just get sick?”
“I’ve heard that the virus is mutating to become airborne.”
With all of the recent concern about Ebola and the flu, it might be a good time to get back to the basics of infection prevention and control. It can be confusing to understand all of the terms, and when we are scared we may forget some of our high school science lessons. Besides, things change quickly in health care and it’s hard to keep up. Join us for a primer in infectious disease.
Can’t You Just Give Me Some Antibiotics?
You get that feeling in the back of your throat or feel a headache coming on…you are going to be sick. You hope you are wrong, but you’ve been here before. But what is it? Bacteria and viruses can cause the same symptoms: fever, headache, nausea, diarrhea or rash.
“With just clinical symptoms, it’s hard to know which one. We are susceptible to both viruses and bacterial infections,” says Dr. Kurt Williamson, an associate professor of biology specializing in viruses at The College of William and Mary.
Bacteria are made of cells, and so they can be treated with antibiotics, which work by blocking the reproduction of the bacteria so your body can catch up and fight it. A virus is not a cell, so antibiotics won’t do anything to it. A virus is a parasite that steals our cells’ resources in order to replicate.
One of the difficulties about diagnosis and treatment of illness is that the results are different for different people. The severity of illness may depend on the strain of virus,the immune system of the person and their genetics.
An Ounce of Prevention: Vaccines
While bacterial infections can be treated with antibiotics, once you are infected with a virus, there’s not much you can do. You can head for bed to rest and increase your fluids. These methods help your immune system fight the virus. That means the best defense against viruses is prevention. The discovery of vaccination as a method of preventing disease was a major milestone in human health.
“At the turn of the 20th century, the top three causes of death were tuberculosis, pneumonia and diarrheal diseases. People died from infections. That’s how it had always been. Then mid-20th century, people died from chronic illnesses and that was a rapid change,” says Dr. Camilla Buchanan, a retired physician and adjunct professor of epidemiology at William and Mary. “Beginning in the middle of the 20th century, deaths from infectious disease decreased dramatically and deaths from, heart disease, cancer and stroke became the top three causes of death.”
“A vaccine presents the infectious agent in a safe and controlled way so that your immune system can later recognize it under real life battle conditions. That’s why vaccines are mostly for viruses. It’s the front line of defense,” says Williamson.
In a first time exposure, your body is naïve (this is the technical term for it, also literally: a lack of experience.) It takes a while to identify that something doesn’t belong, which gives the virus more time to replicate. It’s a race between the virus and your immune system. The virus gets a head start until your immune system catches up and then overcomes it. Next time, the immune system will have protective antibodies and will likely catch up sooner.
Bacteria are made of cells, and so they can be treated with antibiotics, which work by blocking the reproduction of the bacteria so your body can catch up and fight it. A virus is not a cell, so antibiotics won’t do anything to it.
Intricate Influenza, nicknamed “the flu”
We forget how serious influenza is because it is not the threat it once was in the United States. “Our memory is generational, so [influenza is] not the specter that it was. Last time the U.S. had a pandemic with a high percentage of death was the 1918 influenza epidemic. Fifty million people died,” Buchanan says.
Influenza is a virus with nearly 100 strains, or variants, making it very challenging to immunize against—and making identifying it confusing for people who are sick during the winter. Influenza’s characteristics include rapid onset of respiratory symptoms, fatigue, body aches, sore throat and cough.
The seasonal flu shot is targeted at the strains of influenza most likely to be spread in a given year. Researchers who’ve studied the flu look for patterns of which strains are likely to occur for the upcoming flu season (although, that is a misnomer since you can get the flu any time you come in contact with the virus, not just in the winter.)
One of the problems with influenza infections is that they can lead to bacterial infections in the lungs, because influenza can temporarily disable the innate immune function of our lungs. “Part of our immune response is for germs in our lungs to get pushed up and out where we swallow them down to our esophagus and the stomach acids kill them. When that [lung] function is affected, it’s harder to fight the germs,” says Williamson.
A virus is a parasite that steals our cells’ resources in order to replicate.
Ick. I Need to Go Wash My Hands
You probably should. Hand washing is one of the most important ways to prevent transmission of germs, so we can’t recommend that enough.
What else can you do?
“You can boost your immune system, which may shorten the duration. And once we [as a group] identify the source of an illness or virus, we can prevent further transmission and prevent exposure to the source,” says Williamson.
Proven ways to boost your immune system are not very exciting—there are so many unknowns about how “the system” of immunity in our body works. Basically, eat a healthy diet, get enough sleep, avoid stress, exercise regularly and have close relationships. You’ll hear about a lot of supplements and fads to boost immunity, but it’s still unknown whether they help.
“Unfortunately, no one alive now remembers feeling personally vulnerable to infectious disease. What we can do is listen to and fund our experts at the CDC and NIH, so that they can prepare and protect us when the time comes,” says Buchanan.
So inoculate yourself with information, get your flu shot and keep up with recommended vaccinations…oh, and you might as well wash your hands, again!
Methods of Transmission
DIRECT: The infection or virus is transmitted by bodily fluids such as: blood, vomit, diarrhea, urine, semen. The person with the virus must have direct physical contact in order to pass it on. Mother to child in utero is another common way of direct transmission.
INDIRECT: A germ or virus survives long enough on a surface to be transferred to a new host. Often it is picked up via a doorknob, a counter, furniture or eating utensils. Often places where sanitation isn’t good or hand-washing isn’t practiced frequently enough have a fecal to oral path: someone doesn’t wipe well and touches their nose, for example.
AIRBORNE: Sometimes a virus can be transmitted through droplets, for example, a sneeze. The flu is airborne in respiratory droplets, but it can’t live long outside a host. But a truly airborne disease lives longer than a few minutes outside the host.
WATERBORNE & FOODBORNE: disease-causing microbes are contained in something you eat or drink. Chemicals as well as infectious agents can cause illness, often called “food poisoning.” Salmonella and norovirus are the most common foodborne viruses.
VECTOR BORNE: Animals and Insects carry the disease and spread it, like mosquitos and malaria, ticks and Lyme disease and rats and the plague.
Is it a Virus or Bacteria?
|Cannot be treated with antibiotics||Can be treated with antibiotics|
|Vaccines can help fight because they identify viruses and fight them sooner||Cellular growth that gets out of hand is an infection|
|Bed rest and fluids are the best treatment for a virus – your immune system needs to fight the virus||Your body needs time to catch up with an infection and antibiotics help buy you time by blocking the bacteria’s growth.|
|Often affect the respiratory system and the digestive system||Bacteria live all over our bodies – good and bad types. Probiotics can help you after you take antibiotics|
|Certain types of viruses can be dormant outside the body for varying amounts of time||Hand-washing and disinfecting are helpful in combating bacteria|
|Certain viruses can be treated with anti-virals, which don’t kill the virus but can inhibit their growth||Bacterial infections commonly come after the flu as a secondary infection|