A communicable disease is a disease that spreads from one person or animal to another. Pathogens such as viruses, bacteria, and fungi cause these diseases.
What are communicable diseases?
A communicable disease is any disease that passes between people or animals. People sometimes refer to communicable diseases as “infectious” or “transmissible” diseases.
Pathogens, including bacteria, viruses, fungi, and protists, cause communicable diseases.
A person may develop a communicable disease after becoming infected by the pathogen. This may happen through:
direct contact with a person carrying the pathogen
contact with contaminated fluids, such as blood, mucus, or saliva
inhaling contaminated lets from another person’s cough or sneeze
receiving a bite from an animal or insect carrying the pathogen
consuming contaminated water or foods
Once a pathogen has entered a person’s body, it will begin replicating. The individual may then begin to experience symptoms.
Some symptoms are a direct result of the pathogen damaging the body’s cells. Others are due to the body’s immune response to the infection.
Communicable diseases are usually mild, and symptoms pass after a few days. However, some can be serious and potentially life threatening.
Types and symptoms
Four main types of pathogens cause infection: Viruses, bacteria, fungi, and protists.
Viruses
Viruses are tiny pathogens that contain genetic material. Unlike other pathogens, they lack the complex structure of a cell. To replicate, they must enter the cells of other living beings. Once inside, they use the cell’s machinery to make copies of themselves.
Some different viruses include
Rhinoviruses
Rhinoviruses are a group of viruses that are responsible for the common cold. Symptoms of a cold may include:
a stuffy or runny nose
sore throat
headache
A person can catch a rhinovirus by inhaling contaminated lets from the cough or sneeze of another person.
Similarly, rhinoviruses spread by people touching their nose, eyes, or mouth after touching items or surfaces that have come into contact with the virus.
Influenza
Influenza viruses are infections that attack the respiratory system. Some potential symptoms include:
fever or chills
stuffy or runny nose
sore throat
cough
headaches
muscle or body aches
fatigue
A person can catch influenza viruses in the same way they may catch rhinoviruses.
HIV
HIV attacks the immune system of its host. This makes the person vulnerable to other infections and diseases.
A person can contract HIV as a result of contact with blood or other body fluids containing the virus.
The symptoms of HIV may develop gradually and in stages. They can include
fever
chills
rash
mouth sores
sore throat
swollen lymph nodes
night sweats
muscle aches
fatigue
The only way a person can be certain they have HIV is to have an HIV test.
Although there is no cure for HIV, medications can help to keep the virus under control. Without such treatment, HIV can develop into AIDS.
Bacteria
Bacteria are microscopic, single celled organisms. They exist in almost every environment on earth, including inside the human body.
Many bacteria are harmless, and some help the body to function. However, bacteria can also cause infections that damage the body.
Some different types of bacterial infection include
Salmonella and Escherichia coli
Salmonella and Escherichia coli (E. coli) are two different types of bacteria that can infect the digestive system.
They typically spread through contaminated foods, such as uncooked meats, and unwashed fruits and vegetables.
Some symptoms of these infections include
abdominal cramps
diarrhea
fever
headache
Tuberculosis
Tuberculosis (TB) is a bacterial infection that primarily attacks the lungs. It may cause the following symptoms:
a cough continuing for more than 3 weeks
loss of appetite
unintentional weight loss
fever
chills
night sweats
A person can catch TB by inhaling tiny lets or “aerosols” from the cough or sneeze of a person who has the infection. However, the American Lung Association state that while TB is contagious, it does not easily spread from person to person.
Fungi
Fungi are a type of organism that includes yeasts, molds, and mushrooms. There are millionsTrusted Source of different fungi, but only around 300 cause harmful illnesses.
Fungal infections can occur anywhere in the body, but they commonly affect the skin and mucus membranes. Some different types of fungal infection include:
Ringworm
Ringworm is a common fungal infection of the skin. The characteristic symptom of ringworm is a red or silver ring shaped rash. It may be dry, scaly, or itchy.
People may contract ringworm in the following ways through close contact with a person who has ringworm. Alternatively, they can catch it from sharing towels, bedding, or other personal items with a person who has ringworm.
Without treatment, ringworm may spread to other parts of the body.
Athlete’s foot
Athlete’s foot is a common fungal infection that affects the skin on the feet. It typically causes sore or itchy white patches between the toes.
People can contract athlete’s foot through direct contact with someone who has the fungus, or surfaces that have been in contact with the fungus.
For example, an individual might contract athlete’s foot after walking barefoot in locker rooms, showers, or swimming pools.
Protists
Protists are microscopic organisms that typically consist of a single cell.
Some protists are parasitic, meaning they live on or inside another organism and use the organism’s nutrients for their own survival. Parasitic protists can cause various diseases.
The protist Plasmodium causes the tropical disease malaria. The parasite can pass from person to person through mosquito bites.
Malaria causes symptoms such as
fever and chills
headaches
vomiting
diarrhea
muscle pains
Without proper treatment, malaria can be life threatening.
How to prevent transmission
People can reduce their risk of contracting or transmitting disease causing pathogens by following the steps below:
washing their hands thoroughly and regularly
disinfecting surfaces at home often, especially doorknobs and food areas
practicing good hygiene when preparing and handling food
avoiding eating spoiled food
avoiding touching wild animals
receiving available vaccinations
taking antimalarial medications when traveling where there is a malaria risk
