Back to: MICROBIOLOGY 400 LEVEL
Welcome to class!
Hello, amazing learner! It’s always wonderful to have you back, eager and ready to learn. Today’s lesson is about something that affects our everyday lives and health—Environmental Sources of Infectious Diseases. You’ll see how the places we live in, the water we drink, and even the air we breathe can play a big role in how infections spread. Let’s learn how to stay safer by understanding the world around us.
Environmental Sources Of Infectious Diseases
Infectious diseases are illnesses caused by harmful microbes like bacteria, viruses, fungi, and parasites. These diseases don’t just appear from nowhere—they often come from the environment. That means the soil, water, air, and surfaces we touch can all act as sources or carriers of these infections.
Let’s look at the main environmental sources one by one.
1. Water
Water is one of the most common sources of infection, especially when it is contaminated with human or animal waste. Diseases like cholera, typhoid fever, hepatitis A, and giardiasis can be spread through dirty water. This is why clean, treated water is so important.
Example: In some parts of Nigeria where open defecation still happens, rainfall can wash waste into rivers used for drinking or cooking. That can lead to disease outbreaks.
2. Air
When people cough, sneeze, or even talk, they release tiny droplets that can float in the air. In crowded or poorly ventilated spaces, these droplets can carry diseases like tuberculosis, COVID-19, and influenza. Dust and smoke can also carry microbes.
3. Soil
Soil can harbour microbes that cause infections, especially if it contains faeces, decaying matter, or animal waste. Tetanus, for instance, is caused by bacteria found in soil entering wounds.
4. Surfaces and Objects
We call these fomites—objects like door handles, mobile phones, or shared utensils. If an infected person touches them, the germs can stay behind and infect others who touch the same object.
5. Food
If food is grown or prepared in unhygienic conditions, it can carry microbes that cause diseases like food poisoning, salmonellosis, and listeriosis.
Summary
- Infectious diseases often come from environmental sources like water, air, soil, surfaces, and food.
- Dirty water can cause diseases like cholera and typhoid.
- Airborne microbes spread through coughing and sneezing.
- Soil and surfaces can carry harmful microbes if not properly managed.
Evaluation
- List three environmental sources of infectious diseases.
- Mention one disease caused by each of the following: dirty water, air, and soil.
- Why is it important to treat drinking water?
The more you understand your environment, the better you can protect yourself and others. Keep learning, keep growing—Afrilearn is always here to support your bright future. See you in the next exciting lesson!