A bacterium, B, causes food poisoning when people eat contaminated soft cheese. The bacterium can enter the milk of infected goats.
Goats in three regions were vaccinated against bacterium B. Each region had a similar number of goats, and people ate similar amounts of the cheese.
| Region | Goats vaccinated (%) | Milk samples containing bacterium B (%) | Cases of food poisoning per 10 000 people |
|---|---|---|---|
| P | 25 | 16 | 14 |
| Q | 60 | 8 | 7 |
| R | 92 | 2 | 2 |
Using the data, explain how vaccinating the goats reduces the number of cases of food poisoning in humans.
Suggest why cases of food poisoning still occurred in region R.
252 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.