Infectious Diseases
Understanding Infectious Diseases
Infectious diseases: diseases caused by the presence and activity of pathogenic microbial agents.
Infectious diseases: infectious diseases that can be transmitted, for example, from person to person through direct contact with an infected individual or bodily fluids secreted by that person, or indirectly, for example, through vectors.
Infectious diseases are conditions caused by organisms such as bacteria, viruses, fungi, or parasites.
These organisms are usually harmless or even beneficial, but under certain conditions, some of them can cause disease.
Some infectious diseases can be transmitted from person to person. Others are transmitted through insect or animal bites.
Other diseases are contracted through the consumption of contaminated food or water, or through exposure to organisms in the environment. Many infectious diseases, such as measles and chickenpox, can be prevented by vaccination.
Maintaining hand hygiene Frequent and thorough handwashing also helps protect you from most infectious diseases.
Symptoms
Symptoms vary depending on the organism causing the infection, but often include fever and fatigue. Mild infections may improve with rest and home care, while some life-threatening infections may require hospitalization.
Every infectious disease has its own specific signs and symptoms.
Common signs and symptoms that often occur in a number of infectious diseases include:
• Fever
• Diarrhea
• Fatigue
• Muscle pain
• Cough
Causes and modes of transmission
Infectious diseases can be caused by:
Bacteria.
This single-celled organism causes diseases such as strep throat, urinary tract infections, and tuberculosis.
Virus.
Smaller than bacteria, viruses cause a variety of diseases, ranging from the common cold to AIDS.
Mushrooms.
Many skin conditions, such as ringworm and jock itch, are caused by fungi. Other types of fungi can infect the lungs or the nervous system. Peeling, scaling, crusting, or flaking of the skin in the pigmented area around the nipple (areola) or on the breast skin
Parasite.
Malaria is caused by a tiny parasite transmitted through mosquito bites. Other parasites can be transmitted to humans through animal feces.
Infectious agents can enter your body through:
• Skin contact or wounds
• Inhaling airborne germs
• Consuming contaminated food or water
• Tick or mosquito bites
• Sexual contact
• Direct contact
One of the easiest ways to contract most infectious diseases is through contact with infected people or animals.
The three ways infectious diseases can spread through direct contact are:
• From person to person.
A common way for infectious diseases to spread is through the direct transmission of bacteria, viruses, or other germs from one person to another. This can occur when a person carrying bacteria or a virus touches, kisses, coughs, or sneezes toward someone who is not yet infected. Germs can also spread through the exchange of bodily fluids during sexual contact. People who transmit germs may not have any symptoms of the disease and may simply be carriers.
• From animals to humans.
Bites or scratches from infected animals—even pets—can make you sick and, in extreme cases, can be fatal. Handling animal feces can also be dangerous. For example, you can contract toxoplasmosis while cleaning a cat’s litter box.
• From mother to unborn baby.
Pregnant women can transmit germs that cause infectious diseases to their unborn babies. Some germs can cross the placenta. Germs in the vagina can be transmitted to the baby during childbirth.
• Indirect contact
Disease-causing organisms can also be transmitted through indirect contact. Many germs can survive on inanimate objects, such as table surfaces, doorknobs, or faucet handles. For example, when you touch a doorknob that has been touched by someone with the flu or a cold, you can be exposed to the germs they left behind. If you then touch your eyes, mouth, or nose before washing your hands, you can become infected.
• Indirect bite
Some microorganisms rely on insect or arthropod carriers—such as mosquitoes, fleas, lice, or ticks—to move from one host to another. These carriers are known as vectors. Mosquitoes can carry the malaria parasite, the West Nile virus, and the dengue virus, while deer ticks can carry the bacteria that cause Lyme disease.
• Food Contamination
Another way disease-causing germs can infect you is through contaminated food and water. This mode of transmission allows germs to spread to many people from a single source. E. coli, for example, is a bacterium found in or on certain foods, such as undercooked eggs or unpasteurized fruit juice.
Risk factors
Although anyone can catch an infectious disease, you may be more likely to get sick if your immune system isn’t working properly.
This can happen if:
• You are taking steroids or other medications that suppress the immune system, such as medications to prevent organ transplant rejection
• You have HIV or AIDS
• You have a specific type of cancer or another condition that affects your immune system
In addition, certain other medical conditions can increase susceptibility to infection, including implanted medical devices, malnutrition, and being very young or very old.
complications
Most infectious diseases cause only mild complications.
However, some infections, such as pneumonia, AIDS, and meningitis, can be life-threatening.
Several types of infections have been linked to an increased long-term risk of cancer:
• Human papillomavirus (HPV) is associated with cervical cancer
• Helicobacter pylori is associated with stomach cancer and peptic ulcers
• Hepatitis B and C have been linked to liver cancer
In addition, some infectious diseases can become dormant and reappear at a later time, sometimes even decades later. For example, someone who has had chickenpox may develop shingles much later in life.
Prevention
Follow these tips to reduce your risk of becoming infected or spreading the infection to others:
01
Wash your hands.
Apply hand hygiene in daily life. This is especially important before and after preparing food, before eating, and after using the restroom. Try not to touch your eyes, nose, or mouth with your hands, as this is a common way for germs to enter the body.
02
Get vaccination.
Vaccinations can greatly reduce the risk of contracting many diseases. Be sure to follow the recommended vaccination schedule—and make sure your children do as well.
03
Stay home when you're sick.
Do not go to work if you are vomiting, have diarrhea, or have a fever. Do not send your child to school if they have these signs and symptoms.
04
Prepare food safely.
Keep your countertop and other kitchen surfaces clean while preparing food. Cook food thoroughly; undercooked meat and raw eggs can harbor organisms that cause infections. Also, store leftovers in the refrigerator immediately. Do not leave cooked food at room temperature for long periods of time.
05
Practice safe sex.
Always use a condom if you or your partner have a history of sexually transmitted infections or engage in high-risk behavior.
06
Do not share personal items.
Use your own toothbrush, comb, and razor. Avoid sharing drinking glasses or eating utensils.
07
Travel wisely.
If you are traveling abroad, talk to your doctor about any specific vaccinations you may need, such as meningitis, hepatitis A, hepatitis B, or typhoid fever.
Diagnosis
A thorough interview about your symptoms and medical history is essential for determining the possible causes of the infection. A physical examination is also necessary to assess the severity of the illness. Your doctor may order laboratory tests, such as blood, urine, or stool tests, as well as imaging scans to help confirm the most likely cause of the infection.
Treatment
Knowing the type of germ that causes a disease makes it easier for doctors to choose the right treatment.
01.
Antibiotics
Treatment can be tailored more effectively if the doctor knows the type of bacteria causing your infection.
Antibiotics are typically used to treat bacterial infections, since this type of medication has no effect on illnesses caused by viruses.
The proper use of antibiotics is essential to prevent the misuse of these drugs.
The overuse of antibiotics has caused some types of bacteria to become resistant to one or more types of antibiotics. As a result, antibiotics have become ineffective, and the bacteria that cause infections have become much more difficult to treat.
02.
Antivirus
Drugs have been developed to treat some types of viruses, but not all of them. Examples include viruses that cause:
• HIV/AIDS
• Herpes
•Hepatitis B
• Hepatitis C
• Influenza
03.
Antifungal.
Topical antifungal medications can be used to treat fungal infections of the skin or nails. Some fungal infections, such as those affecting the lungs or mucous membranes, can be treated with oral antifungal medications. More severe fungal infections of internal organs, especially in people with weakened immune systems, may require antifungal medications administered intravenously.
04.
Antiparasitic
Some diseases, including malaria, are caused by tiny parasites and can be treated with antimalarial drugs.Schedule an appointment at the Mayo Clinic
Alternative Medicine
A number of products are claimed to help prevent common illnesses, such as the common cold or the flu. Although some of these substances have shown promising results in preliminary studies, follow-up studies may yield negative results or may not yet allow for a definitive conclusion. More research is needed.
Some substances that have been studied for their ability to prevent or shorten the duration of infection include:
Cranberry
Echinacea
Garlic
Ginseng
Goldenseal
Vitamin C
Vitamin D
Zinc