10. Infectious diseases

The infectious diseases studied in this topic are caused by pathogens that are transmitted from one human host to another. Some, like Plasmodium that causes malaria, are transmitted by vectors, but there are many other methods of transmission, such as through water and food or during sexual activity. An understanding of the biology of the pathogen and its mode of transmission is essential if the disease is to be controlled and ultimately prevented.

10.1 Infectious diseases

1. state that infectious diseases are caused by pathogens and are transmissible

2. state the name and type of pathogen that causes each of the following diseases:

• cholera – caused by the bacterium Vibrio cholerae • malaria – caused by the protoctists Plasmodium falciparum, Plasmodium malariae, Plasmodium ovale and Plasmodium vivax

• tuberculosis (TB) – caused by the bacteria Mycobacterium tuberculosis and Mycobacterium bovis

• HIV/AIDS – caused by the human immunodeficiency virus (HIV)

3. explain how cholera, malaria, TB and HIV are transmitted

4. discuss the biological, social and economic factors that need to be considered in the prevention and control of cholera, malaria, TB and HIV (details of the life cycle of the malarial parasite are not expected)

10.2 Antibiotics

1. outline how penicillin acts on bacteria and why antibiotics do not affect viruses

2. discuss the consequences of antibiotic resistance and the steps that can be taken to reduce its impact