Question

Name some external agencies responsible for causing disease.

Answer 1

External agencies: The disease-causing agents entering the human body from outside are referred to as ‘External agencies’. These external agencies or factors such as environmental pollutants enter the human body and interfere with the normal body functioning which ultimately results in illnesses such as respiratory diseases, heart failures, etc.

Some of the external factors are as follows:

1. Environmental pollutants: The most common pollutants of the environment include carbon dioxide, sulfur dioxide, nitrogen oxide, industrial chemicals, particulate matter, and heavy metals like mercury, arsenic, and lead. Respiratory diseases like asthma and breathlessness are caused by environmental pollutants.
2. Unbalanced diet: The deficiency of nutrient-rich food in the diet results in many deficiency diseases in human beings. For instance, the deficiency in Vitamin A leads to Night blindness in human beings.
3. Pathogens: Pathogens such as viruses, bacteria, fungi, protozoa, and worms are transferred to the human body through air, water, contaminated food, physical contact, and sexual contact. Common cold, Influenza, Measles, Mumps, Hepatitis, Chickenpox, and Typhoid are diseases caused by pathogens.
4. Tobacco, alcohol, and drugs: The continuous and sustained intake of tobacco, alcohol, and drugs leads to chronic diseases such as tuberculosis, diabetes, asthma, etc.