Chapter 2 : Causes and Symptoms

Topics covered in this snack-sized chapter:



Causes of Cold and Flu arrow_upward


  • Both colds and flu are caused by viruses, and the real difference between them is simply the type of virus that causes the illness.
    • Colds are caused by a number of different viruses, but especially rhinoviruses ("rhino" is Greek for nose, so these are "nose viruses").
    • Flu is caused by influenza viruses.

    Causes of Common Cold arrow_upward


  • When you get cold, you've probably been infected by one of more than 200 different viruses.
  • These viruses easily spread through droplets of fluid from a cough, sneeze, or runny nose.
  • Cold viruses often circulate by touch, but they can also be inhaled if they become airborne.
  • People with colds are most contagious during the first few days after they have been infected with a virus.
  • Spending a lot of time around other people indoors can help spread colds - a common occurrence for schoolchildren.
  • Also, low humidity (especially during the winter months), makes an ideal living environment for viruses.

    • Rhinoviruses arrow_upward


  • Rhinoviruses are most active near the beginning of fall, spring and summer and grow best at 33 degrees Celsius (which is the temperature of the human nasal mucosa).
  • There are over 110 kinds of rhinovirus.
  • Para influenza and RSV are other cold viruses which create mild infections in adults but in young children can cause severe lower respiratory infections like pneumonia.

    • Coronaviruses arrow_upward


  • Coronaviruses are most active in the winter and near the beginning of spring and cause a large percentage of adult colds.
  • There are over 30 kinds of coronaviruses of which 3 or 4 infect humans.
  • Unlike rhinoviruses, coronaviruses are not easily cultivated in the laboratory so evaluating the significance of coronaviruses as causative agents is hard.

    • Allergies and Stress arrow_upward


  • Significant contributory causes of cold are:
    • Low vitality,
    • Exposure to low temperatures,
    • Lack of sleep,
    • Depression,
    • Fatigue,
    • Factors like unexpected alterations in temperature, dust and other irritating inhalations.

    Causes of Flu arrow_upward


  • The flu is actually very different from a cold.
  • While more than 100 different viruses can cause a cold, only influenza viruses of types A, B and C cause the flu.
  • Type A and B viruses are responsible for the large flu epidemics.
  • Type C flu virus is more stable and usually causes milder respiratory symptoms.
  • While the flu vaccine can help protect you from type A and B flu viruses, there is no immunization or flu shot for a type C virus.
  • Type A flu virus is divided into different subtypes based on the chemical structure of the virus.
  • Type B flu virus is not divided into subtypes.
  • Both type A and type B flu viruses are responsible for the seasonal outbreaks of flu.
  • Type A flu viruses are found in many different animals, including ducks, chickens, pigs, whales, horses and seals. Influenza B viruses circulate widely only among humans.

    • How does the Flu Virus Spread? arrow_upward


  • The flu virus spreads when you either inhale infected droplets in the air or when you come in direct contact with an infected person's secretions.
  • You can also transfer the flu virus through your hands by touching smooth surfaces such as doorknobs, handles, television remotes, computer keyboards, and telephones.
  • Then, when you touch your hands to your nose, eyes, or mouth, the flu virus gets absorbed.

    • Why Do People usually get the Flu in winter? arrow_upward


  • Flu outbreaks occur more frequently in the winter months.
  • Many factors may play a role in the flu's seasonal pattern.
    • The flu virus survives for longer periods indoors in winter because the relative humidity of indoor air is very low in comparison to the outside air.
    • The flu virus may stay suspended in the air for prolonged periods and thus infect others by being inhaled. The flu virus droplets can also infect by landing on sensitive body areas such as the eyes, nose or mouth.
    • In winter, humans tend to be indoors more and thus have closer contact with each other, which makes it easier for the flu virus to spread.

    Infectious Causes of Flu-like Symptoms arrow_upward


  • Flu-like symptoms are associated with many different types of infections:
    • Appendicitis,
    • Bronchitis,
    • Common cold (viral respiratory infection),
    • Influenza,
    • Meningitis (infection or inflammation of the sac around the brain and spinal cord),
    • Pneumonia,
    • Septic arthritis (infectious arthritis),
    • Sexually transmitted diseases, such as genital herpes and HIV/AIDS,
    • Tuberculosis (serious infection affecting the lungs and other organs),
    • Urinary tract infection.

    Other Causes of Flu-Like Symptoms arrow_upward


  • Flu-like symptoms can also be caused by inflammatory conditions and other abnormal processes including:
    • Cancer, such as leukemia or lymphoma,
    • Chronic fatigue syndrome,
    • Inflammatory bowel disease (includes crohn’s disease and ulcerative colitis),
    • Rheumatoid arthritis (chronic autoimmune disease characterized by joint inflammation),
    • Systemic lupus erythematosus (disorder in which the body attacks its own healthy cells and tissues).

    Cold: Symptoms arrow_upward



    Symptoms

    Cold

    Fever

    Common in children

    Muscle Aches

    Mild, infrequent

    Fatigue

    Mild, brief

    Nausea, Vomiting, and Diarrhea

    Uncommon

    Congestion, runny nose, sore throat

    Common especially in the early stages of illness


  • Colds usually start two to three days after the virus enters the body and symptoms last from several days to several weeks.


    • Flu: Symptoms arrow_upward



    Symptoms

    Flu

    Fever

    Common in children and adults

    Muscle Aches

    Very common, often severe

    Fatigue

    Can be severe and last several weeks

    Nausea, Vomiting and Diarrhea

    Common, especially in children

    Congestion, runny nose, sore throat

    Common, but late in course of illness



    Difference between the Cold and Flu Symptoms arrow_upward


  • The main difference between the common cold and the flu (influenza) is the severity of the symptoms.

    • Symptoms

    Cold

    Flu

    Aches, pains

    Slight

    Common, often severe

    Chest Discomfort

    Mild to moderate

    Common to severe

    Chills

    Rare

    Common

    Cough

    Hacking (a short, weak repeating cough), productive cough (cough that produce phlegm)

    Dry, unproductive cough (cough not accompanied by expectoration)

    Extreme exhaustion

    Never

    Early and prominent

    Fatigue

    Mild

    Moderate to severe, can last up to 2-3 weeks

    Fever

    Rare

    Common, high (102-104F or 39-40C); lasts for days

    Headache

    Rare

    Common

    Sneezing

    Common

    Sometimes

    Sore throat

    Common

    Sometimes

    Stuffy nose

    Common

    Sometimes

    Other possible health problem

    Usually no

    Pneumonia, bacterial infections, or hospitalizations




    Thank You from Kimavi arrow_upward


  • Please email us at admin@kimavi.com and help us improve this tutorial.