How are communicable disease cause?
Communicable diseases are caused by infectious agents such as bacteria, viruses, fungi, or parasites. These agents can be transmitted through various means, including:
1. Direct contact: This involves physical contact with an infected person or animal, such as touching, kissing, or sharing bodily fluids. For example, the common cold and influenza (flu) are spread through direct contact with respiratory droplets from an infected person's cough or sneeze.
2. Indirect contact: This occurs when a person comes into contact with contaminated objects or surfaces that have been touched or handled by an infected individual. For instance, touching doorknobs, countertops, or utensils contaminated with bacteria or viruses can lead to infection.
3. Airborne transmission: Certain diseases are spread through the air when infected individuals release respiratory droplets or aerosols containing infectious agents. These droplets can remain suspended in the air and be inhaled by others, even at a distance. Examples of airborne diseases include tuberculosis (TB) and measles.
4. Fecal-oral transmission: This involves the ingestion of contaminated food or water that contains infectious microorganisms. Improper food handling, poor sanitation, and consumption of untreated water can lead to diseases such as typhoid fever, cholera, and dysentery.
5. Vector-borne transmission: This occurs when insects or other animals, known as vectors, transmit infectious agents from one host to another. For example, mosquitoes transmit malaria, dengue fever, and yellow fever; ticks transmit Lyme disease and Rocky Mountain spotted fever; and fleas transmit plague.
6. Blood-borne transmission: Some diseases are spread through contact with infected blood or blood products. This can occur during blood transfusions, sharing needles or other drug paraphernalia, or through occupational accidents involving needles or sharp objects. Examples of blood-borne diseases include HIV/AIDS, hepatitis B, and hepatitis C.
7. Congenital transmission: Certain infections can be passed from a pregnant mother to her developing fetus before or during childbirth. These infections, known as congenital infections, can cause serious health problems in newborns. Examples include rubella (German measles), cytomegalovirus (CMV), and toxoplasmosis.