Back to: MICROBIOLOGY 300 LEVEL
Welcome to class!
Hello, superstar! It’s always a pleasure to have you here. You’ve been growing into a microbiology master, and I’m so proud of your journey. Today, we’re going to learn about a very interesting group of fungi—Aspergillus species, and the illness they cause called Aspergillosis. This topic is very important, especially for people with weak immune systems. Let’s go through it together, like a friendly conversation, so it’s easy to understand and even easier to remember.
Aspergillus Spp. (Aspergillosis)
Have you ever seen that green or black fuzzy mould growing on old bread or groundnuts? That could be Aspergillus! It’s a very common mould found all around us—in soil, dust, decaying leaves, and even the air we breathe. Most people inhale Aspergillus spores every day without getting sick because their immune system fights it off. But in people with weakened immunity, it can cause an illness called Aspergillosis.
So just like rain doesn’t harm a strong roof but leaks into a damaged one, Aspergillus usually only causes problems when the body’s defences are down.
About Aspergillus spp.
Aspergillus is a genus of fungi with over 180 species.
The most common disease-causing species include:
Aspergillus fumigatus (most common)
Aspergillus flavus
Aspergillus niger
These fungi reproduce by producing spores (conidia) that float in the air and can be inhaled.
Types of Aspergillosis
Allergic Bronchopulmonary Aspergillosis (ABPA)
This affects people with asthma or cystic fibrosis.
The immune system overreacts to Aspergillus, causing wheezing, coughing, and breathing difficulty.
It’s an allergic reaction, not a true infection.
Aspergilloma (Fungal Ball)
A mass of fungus that forms in an already damaged lung cavity, like from tuberculosis.
May cause coughing with blood (haemoptysis).
Think of it like dirt collecting in a pothole—because the cavity is there, something settles in it.
Invasive Aspergillosis
The most dangerous form, seen in patients with very weak immune systems (e.g. cancer, HIV/AIDS, transplant).
The fungus spreads through the lungs and into the blood, affecting other organs.
Requires urgent medical attention.
How Aspergillosis is Diagnosed
Doctors diagnose it using:
Chest X-rays or CT scans – to see fungal balls or lung damage.
Microscopy and culture – examining sputum or tissue samples under a microscope.
Blood tests – to detect fungal antigens.
Treatment of Aspergillosis
Treatment depends on the type and severity:
Antifungal medications: e.g. voriconazole, itraconazole.
Surgery: to remove fungal balls in some cases.
Steroids: for allergic forms like ABPA.
Preventive measures include avoiding areas with a lot of dust, mould, or decaying matter—especially for people with low immunity.
Imagine you live near a dusty roadside. If you keep your windows closed and your house clean, you’re mostly fine. But if you’re already sick or your window is broken, dust can enter and cause harm. Aspergillus works like that—it’s all around us, but only causes trouble if our natural defences are down.
Summary
- Aspergillus spp. are common moulds found in the environment.
- They cause Aspergillosis, which ranges from mild allergic reactions to life-threatening infections.
- People with lung diseases or weak immune systems are at higher risk.
- Diagnosis involves imaging, lab tests, and fungal cultures.
- Treatment includes antifungal medications and, in some cases, surgery or steroids.
Evaluation
- Where is Aspergillus commonly found in the environment?
- What type of person is most at risk for invasive aspergillosis?
- Name two common disease-causing Aspergillus species.
- What is an aspergilloma?
- How is aspergillosis treated?
Wow! You’ve just unlocked another level in your microbiology journey. You’re becoming a strong, confident, and wise learner—one who can understand diseases and help others. This knowledge you’ve gained is powerful, and it’s only the beginning. Keep shining, keep growing. We at Afrilearn are proud of you and can’t wait to learn more with you in the next class!