Treatment training manual

2. 4 Other causes of illness

As well as viruses, other things can affect your health. This includes bacteria, fungi, parasites and protozoa.

Different types of drugs are used for each infection. For example, antibiotics work against bacteria but do not work against viruses.

The difference between viral, bacterial and fungal infections is not always clear.

However, sometimes drugs designed to treat one kind of infection also work against a another type. This is complicated because it applies only to individual drugs for specific infections.


Bacteria are single-cell microorganisms. Some bacteria are healthy and help your body. Some bacteria and dangerous and cause disease. Antibiotic drugs are used to treat bacterial infections.

Examples of bacterial infections that affect people with HIV include tuberculosis, bacterial pneumonia, sinusitis, gonorrhoea and some skin infections.


Fungi are parasitic organisms that include moulds, mildews, mushrooms and yeast. Antifungal drugs are used to treat fungal infections.

Examples of fungal infections that affect people with HIV include candida (thrush) and cryptococcosis.

Parasites and protozoa

A parasite is an animal or plant that gets nutrients and support from another species. This includes protozoa which are single-celled animals that are larger and more complex than bacteria.

Examples of parasite-related infections are cryptosporidium and microsporidium. Toxoplasmosis is an illness causes by protozoa.

Last updated: 1 January 2016.