Infectious diseases Symptoms and causes

General description

Infectious diseases are disorders that are caused by organisms, such as bacteria, viruses, fungi or parasites. Many organisms live inside and on our bodies. They are usually harmless or even useful, but under certain conditions, some organisms can cause disease.

Some infectious diseases can be transmitted from one person to another. Some are transmitted by insect or animal bites. And others are acquired by ingesting contaminated food or water or by being exposed to organisms in the environment.

Signs and symptoms vary depending on the organism that causes the infection but often includes fever and fatigue. Mild infections may respond to rest and home remedies, while some life-threatening infections may require hospitalization.

Many infectious diseases, such as measles and chickenpox, can be prevented with vaccines. Frequent and thorough hand-washing also helps protect you from most infectious diseases.


Each infectious disease has specific signs and symptoms. General signs and symptoms that are common in many infectious diseases include:

  • Fever
  • Diarrhea
  • Fatigue
  • Muscle pains
  • Cough
When to consult the doctor

Seek medical attention if:

  • An animal bit you
  • You have trouble breathing
  • You have a cough for more than a week
  • You have a severe headache with a fever
  • You have a rash or swelling
  • You have a prolonged fever and no apparent cause
  • You have sudden vision problems

The causes of infectious diseases can be the following:

Bacteria these unicellular organisms cause diseases such as streptococcal tonsillitis, urinary tract infections, and tuberculosis.

Virus. Viruses are even smaller than bacteria, but they can cause numerous diseases: from the common cold to AIDS.

Mushrooms. Many skin diseases, such as ringworm and athlete’s foot, occur because of fungi. There are other types of fungi that can infect the lungs or nervous system. To read more about the different diseases visit here mediologest.

Parasites Malaria is caused by a tiny parasite that is transmitted through mosquito bites. There are other parasites that can be transmitted to humans through animal feces.

Direct contact

A simple way to get the most infectious diseases is to come into contact with an infected person or animal. There are three ways in which infectious diseases are spread by direct contact:

From person to person. One form of frequent spread of infectious diseases is the direct transfer of bacteria, viruses or other germs from one person to another. This happens when a carrier of the bacterium or virus touches or kisses a person who is not infected or coughs or sneezes on it.

These germs are also transmitted in sexual intercourse, by exchanging body fluids. It is possible that the person who transmits the germ does not show symptoms of the disease, but is only a carrier.

From animal to person. The bite or scratch of an infected animal – even a pet – can make you sick and, in extreme cases, can be fatal. Also handling animal waste can lead to hazards. For example, you can become infected with toxoplasmosis by cleaning your cat’s litter box.

From the mother to the fetus. It is possible for a pregnant woman to spread infectious diseases to the fetus. Some germs cross the placenta. Vaginal germs can be transmitted to the baby during birth.

Indirect contact

Disease-causing organisms can also be transmitted by indirect contact. Many germs remain in inanimate objects, such as countertops, doorknobs or tap keys.

By touching a handle that someone who, for example, suffered from influenza or cold, you can take with you the germs that person left. If you touch your eyes, mouth or nose before washing your hands, you may become infected.

Insect bites

Some germs depend on carrier insects – such as mosquitoes, fleas, lice or ticks – to pass from one host to another. These carriers are called “vectors.” Mosquitoes can carry the malaria parasite or West Nile virus, and deer ticks carry the bacteria that cause Lyme disease.

Food contamination

Another way that disease-causing germs can infect you is through contaminated food or water. This transmission mechanism allows germs to infect many people through a single source. For example, E. coli is a bacterium present in certain foods, such as undercooked hamburgers or unpasteurized fruit juice.

Risk factors

While anyone can catch infectious diseases, you may be more likely to get sick if your immune system isn’t working properly. This may occur if:

You’re taking steroids or other medications that suppress your immune system, such as anti-rejection drugs for a transplanted organ

You have HIV or AIDS

You have certain types of cancer or other disorders that affect your immune system

In addition, certain other medical conditions may predispose you to infection, including implanted medical devices, malnutrition, and extremes of age, among others.


Most infectious diseases have only minor complications. However, some infections (for example pneumonia, AIDS and meningitis) can be life-threatening. Some types of infections were linked to an increased risk of long-term cancer:

Human papillomavirus was linked to cervical cancer

Helicobacter pylori bacteria were linked to stomach cancer and peptic ulcers

Hepatitis B and hepatitis C were linked to liver cancer

Also, some infectious diseases become silent and reappear in the future, sometimes decades later. For example, a person who had chickenpox can develop shingles many years later.


Infectious agents can enter the body through:

  • Injuries or skin contact
  • Inhalation of air germs
  • Water or contaminated food intake
  • Mosquito or tick bites
  • Sexual contact

Take these steps to reduce the risk of infection for you and others:

Wash your hands. This is especially important before and after preparing meals, before eating and after using the bathroom. And try not to touch your eyes, nose or mouth with your hands, as this is a common way for germs to enter the body.

Get vaccinated Immunization can greatly reduce the chances of getting many diseases. Make sure you have your recommended and your children’s vaccinations up to date.

Also Read Infection Prevention: Start Preventing Infection From Now

Stay home when you are sick. Do not go to work if you have vomiting, diarrhea or fever. Also, do not send your children to school if they show these signs and symptoms.

Prepare your meals safely. Keep countertops and other kitchen surfaces clean while preparing meals. Cook meals with the proper temperature using a food thermometer to check cooking. In the case of ground meats, the temperature must be at least 160 ºF (71 ºC); in the case of chicken, 165ºF (74ºC); and in the case of the other meats, 145ºF (63ºC).

Also, refrigerate leftovers immediately: do not let prepared meals remain at room temperature for extended periods.

Have safe sex. You should always use condoms if you or your partner have a history of sexually transmitted infections or high-risk behaviors.

Do not share personal effects. Use your own toothbrush, comb, and shaver. Avoid sharing glasses and utensils.

Travel safely. If you will leave the country, talk to your doctor about the special vaccines you may need; for example, for yellow fever, cholera, typhoid fever or hepatitis A or B.

Also Read Drugs To Carry During Travel

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