Understanding Infections

What is an infection?

Bacteria, viruses, fungi or parasites and other microorganisms live in, and on, our bodies. A host of them live on the skin, eyelids, nose, and mouth and in the gut and are they are part of the normal flora of our bodies. Some are helpful, most are harmless, but under certain conditions, some organisms can cause disease.

An infection occurs when these harmful organisms start multiplying. When they damage the cells in your body, the signs and symptoms of an infectious disease appears. Some infectious diseases are minor, while others are serious. HIV, tuberculosis, lower respiratory tract infections and diarrhoeal diseases – all infectious diseases – are among the leading causes of death in South Africa.

Infections are very common amongst children. It’s estimated that children have at least 6 infections each year, mostly colds, diarrhea, ear infections, bronchitis, and pneumonia.

The difference between infectious and non-infectious diseases

Infectious diseases can be caused by consuming contaminated food or water, it can be transmitted from person to person, by insects or other animals or being exposed to organisms in the environment, e.g. the flu, measles, COVID-19, and salmonella.

Non-infectious diseases are caused by genetics, anatomical differences, or aging, such as cancer, diabetes, diabetes and congestive heart failure. heart failure.

There are 5 types of infection:

  • Bacterial infections are caused by bacteria. These one-cell microorganisms live inside our body and on our skin. Common bacterial infections include:
    • urinary tract infections
    • strep throat
    • tuberculosis
    • cholera
    • dysentery
    • typhoid
  • Viral infections are caused by viruses. Smaller than bacteria, viruses are a piece of information (DNA or RNA) inside of a protective shell (capsid) which penetrate the cells to make copies of themselves. Common viral infections include:
    • the common cold
    • flu
    • gastroenteritis
    • herpes
    • measles
    • chicken pox
    • coronavirus
    • meningitis
    • HIV/AIDS
  • Fungal infections are caused by fungi. A fungus can be single-celled or multicellular. Like bacteria, they also live on and in your body. There are three types of fungal infections:
    • Superficial fungal infections affect your nails, skin, and mucous membranes (mouth, throat, or vagina), such as ringworm, athlete’s foot, jock itch, nail infections, thrush (caused by Candida), and dandruff (caused by Malassezia).
    • Subcutaneous (under the skin) fungal infections cause rashes and ulcers.
    • Deep fungal infections affect your lungs, blood, urinary tract, or brain.
  • Parasitic infections are caused by parasites. They use the bodies of other organisms to live and reproduce. Parasites include worms (helminths) and some single-celled organisms (protozoa). Helminths are larger parasites, such as tapeworms and roundworms; malaria is an example of a mosquito-borne parasite caused by protozoa.
  • Prion diseases or transmissible spongiform encephalopathies (TSEs) are caused by prions. They can be infectious, hereditary, or sporadic; however, they are a rare cause of infectious diseases. Prions are faulty proteins that cause other proteins in your body (usually the brain) to become faulty as well. Since the body can’t get rid of them, they build up and make you sick. Prion diseases include bovine spongiform encephalopathy (BSE), better known as mad cow disease, and Creutzfeldt-Jakob disease (CJD).

How infectious diseases are spread

Infectious diseases are spread by:

  1. Direct contact:
    • Person to person. The bacteria, viruses, or other germs are transferred from one person to another, through touching, kissing, coughing, sneezing, or from sexual contact. Schools provide the perfect opportunity for infections to spread.
    • Animal to person. You can get sick if an infected animal bites or scratches you. Handling animal waste can also be dangerous.
    • Mother to unborn child. A pregnant woman can pass germs from the placenta to the unborn child, can transmit germs in the vagina to the baby during birth, and through breast milk.
  2. Indirect contact

    Germs can be passed on via inanimate objects, such as doorknobs, taps, or tabletops.

  3. Insect bites

    Insects, such as mosquitoes, fleas, lice, or ticks, carry parasites allowing them to move from host to host. For instance, mosquitoes can carry the malaria parasite and deer ticks may carry the bacterium that causes Lyme disease.

  4. Food contamination

    Germs and bacterium, such as Escherichia coli (E. coli), can spread through contaminated food and water.

Risk factors

You are more susceptible to pick up an infection when your immune system is weak. People who are more at risk include:

  • those with suppressed or compromised immune systems, such as
    • people receiving cancer treatment
    • those living with HIV or AIDS
    • those with implanted medical devices or using medical devices such as a catheter
    • people with malnutrition
  • young children, pregnant women, and adults over 60
  • those on certain medication such as corticosteroids
  • healthcare workers
  • those who are unvaccinated against common infectious diseases
  • those traveling to areas where they may be exposed to mosquitoes that carry pathogens such as malaria, dengue virus, and Zika viruses.

Symptoms

Each infectious disease has its own specific symptoms. Some infections are mild and have few to no symptoms,
however general signs and symptoms include:

General Active Infection Respiratory Infections (incl. cold & flu) Gastrointestinal Infections
  • Fever
  • Fatigue
  • Headache
  • Muscle aches
  • Swollen lymph nodes
  • Persistent cough
  • Runny nose
  • Sneezing
  • Sore throat
  • Difficulty breathing
  • Diarrhea
  • Nausea
  • Vomiting
  • Stomach pain
  • Loss of appetite

Stages of an infection

An infection typically occurs in five stages:

  1. The incubation stage occurs right after exposure and before symptoms develop. Depending on the infection and the individual, incubation can range from hours for some infections to days, weeks, or even years.
  2. The prodromal stage triggers mild, nonspecific symptoms.
  3. The illness stage shows the characteristic symptoms of the infection, such as a rash in chickenpox.
  4. The decline stage occurs when the symptoms resolve.
  5. The convalescent stage is when symptoms disappear, and the body starts to recover.

If the infection is contagious, you can be contagious from the incubation to the decline stage. Young children are often contagious for longer than older children.

Diagnosis

Because many infectious diseases have similar symptoms, treatment will need to be tailored to the microbe that is causing the illness. Various lab tests can usually determine the cause. Doctors might request:

Laboratory tests:

  • blood tests
  • urine tests
  • swab samples from the throat, or other moist areas of the body
  • stool samples to check for parasites and other organisms
  1. Spinal tap (lumbar puncture). A sample of the cerebrospinal fluid is obtained by inserting a needle carefully between the bones of the lower spine. This can be painful.
  2. Imaging procedures. X-rays, computerized tomography (CT) scans, and magnetic resonance imaging (MRI) can help pinpoint diagnoses and rule out other conditions.
  3. Biopsies. A small sample of tissue is taken from an internal organ for testing, for instance, a biopsy on lung tissue is checked for fungi that can cause a type of pneumonia.

Treatment

Treatment depends on the organisms that are causing the infection. Many infectious diseases – such as the cold – heal on their own, and the only treatment you need is lots of rest and drinking plenty of fluids. Other infections are generally treated by:

  • Antibiotics. Antibiotics are usually used for bacterial infections. Antibiotics are grouped into “families” of similar types, and certain types of bacteria are susceptible to particular classes of antibiotics. Some infections such as pneumonia can be caused by a bacterium, a virus, a fungus, or a parasite, making it harder to treat. Overuse of antibiotics has made several types of bacteria resistant to antibiotics, making them more difficult to treat. Click to read more about antibiotic stewardship: Antibiotic stewardship.
  • Antivirals. Antivirals fight off viral infections, shorten the length of the infection, prevent transmission, and prevent you from getting an infection. They treat viral infections such as HIV/AIDS, herpes, hepatitis B, hepatitis C, and the flu. Infections like HIV, hepatitis, and herpes are chronic, and even though they can’t destroy the virus, antiviral medicines can make the virus latent (inactive) so that you have fewer and milder symptoms.
  • Antifungals. Antifungals treat fungal infections and can be administered in three ways. Topical antifungals treat nail or skin infections; oral antifungals treat infections of the lungs or the mucous membranes, for instance, and intravenous antifungal medications treat severe internal organ fungal infections.
  • Anti-parasitics. Diseases caused by parasites, such as malaria, are treated with anti-parasitics. Over the years, some varieties of parasites have become resistant to the medication, making them harder to treat.

Complications

Many infections heal without complications, but some can be severe and life-threatening. The complications are specific to the individual infectious disease.

Living and managing

If you’ve been diagnosed with an infection, ensure that:

  • Antibiotics are taken properly: complete the course even if symptoms improve. Click for more on antibiotic safety.
  • Stay home when ill and keep your children home when they are ill.
  • Keep your immune system strong by eating a nutritionally balanced diet and exercising regularly.

Prevention

While you can’t protect yourself completely against all infections, you can prevent microbes from spreading:

  • Wash your hands regularly, especially after using the toilet, before and after preparing food, and after eating. Try not to touch your eyes, nose, or mouth often with your hands; this is how germs spread.
  • Ensure that you and your children are up to date with the recommended vaccinations.
  • Cover your nose and mouth when you sneeze or cough.
  • Don’t swim in water that could be contaminated.
  • Disinfect rooms that may have a lot of bacteria, such as the kitchen and bathroom.
  • Reduce the risk of sexually transmitted infections (STIs) by receiving regular STI checks, using condoms, or abstaining altogether.
  • Practice safe sex – use condoms if you or your partner has a history of sexually transmitted infections or high-risk behavior.
  • Prepare food safely. Keep the kitchen counters and utensils clean when preparing food. Don’t leave leftovers at room temperature for long periods of time.
  • Don’t share personal items. Use your own toothbrush, comb, and razor.
  • Avoid sharing drinking glasses or dining utensils.
  • Vaccinate ahead of travelling – if you’re travelling to another country, ensure that you have the necessary vaccinations such as yellow fever and hepatitis A/B.
  • To reduce the risk of mosquito bites: use insect repellent for mosquitoes, cover as much exposed skin as you can with clothing and don’t wear dark clothing.
References
  1. 1. American Academy of Pediatrics. (2015). Overview of Infectious Diseases. American Academy of Pediatrics Healthychildren.org [Online]. Accessed on 3 November 2023.
  2. 2. Boyles, T., Mendelson, M., Govender, N., & Du Plessis, N. (2019). The infectious diseases specialty in South Africa is in crisis. South African Medical Journal. 109(9), 620–621.
  3. 3. Cleveland Clinic. (2022). Infectious Diseases. Cleveland Clinic [Online]. Accessed on 3 November 2023.
  4. 4. Cleveland Clinic. (2023). Sepsis. Cleveland Clinic [Online]. Accessed on 3 November 2023.
  5. 5. Cleveland Clinic. (2021). Antivirals. Cleveland Clinic [Online]. Accessed on 20 November 2023.
  6. 6. Eske, J. (2021). The 5 stages of infection explained. Medical News Today [Online]. Accessed on 16 November 2023.
  7. 7. Felman, A. (2023). What to know about infections. Medical News Today [Online]. Accessed on 16 November 2023.
  8. 8. Cleveland Clinic (2022). Fungal Infections (Mycosis). Cleveland Clinic [Online]. Accessed on 20 November 2023.
  9. 9. Mayo Clinic. (2022). Germs: Understand and protect against bacteria, viruses and infections. Mayo Clinic [Online]. Accessed on 13 November 2023.
  10. 10. Mayo Clinic. (2022). Infectious diseases Symptoms & Causes. Mayo Clinic [Online]. Accessed on 3 November 2023.
  11. 11. Mayo Clinic. (2022). Infectious Diseases Diagnosis & Treatment. Mayo Clinic [Online]. Accessed on 13 November 2023.
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References
  1. 1. American Academy of Pediatrics. (2015). Overview of Infectious Diseases. American Academy of Pediatrics Healthychildren.org [Online]. Accessed on 3 November 2023.
  2. 2. Boyles, T., Mendelson, M., Govender, N., & Du Plessis, N. (2019). The infectious diseases specialty in South Africa is in crisis. South African Medical Journal. 109(9), 620–621.
  3. 3. Cleveland Clinic. (2022). Infectious Diseases. Cleveland Clinic [Online]. Accessed on 3 November 2023.
  4. 4. Cleveland Clinic. (2023). Sepsis. Cleveland Clinic [Online]. Accessed on 3 November 2023.
  5. 5. Cleveland Clinic. (2021). Antivirals. Cleveland Clinic [Online]. Accessed on 20 November 2023.
  6. 6. Eske, J. (2021). The 5 stages of infection explained. Medical News Today [Online]. Accessed on 16 November 2023.
  7. 7. Felman, A. (2023). What to know about infections. Medical News Today [Online]. Accessed on 16 November 2023.
  8. 8. Cleveland Clinic (2022). Fungal Infections (Mycosis). Cleveland Clinic [Online]. Accessed on 20 November 2023.
  9. 9. Mayo Clinic. (2022). Germs: Understand and protect against bacteria, viruses and infections. Mayo Clinic [Online]. Accessed on 13 November 2023.
  10. 10. Mayo Clinic. (2022). Infectious diseases Symptoms & Causes. Mayo Clinic [Online]. Accessed on 3 November 2023.
  11. 11. Mayo Clinic. (2022). Infectious Diseases Diagnosis & Treatment. Mayo Clinic [Online]. Accessed on 13 November 2023.

These articles are for information purposes only. It cannot replace the diagnosis of a healthcare provider. Pharma Dynamics gives no warranty as to the accuracy of the information contained in such articles and shall not, under any circumstances, be liable for any consequences which may be suffered as a result of a user’s reliance thereon.

The information the reader is about to be referred to may not comply with the South Africa regulatory requirements. Information relevant to the South African environment is available from the Company and in the Professional Information/Patient Information Leaflet/Instructions for Use approved by the Regulatory Authority.

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