Ch 23 Infectious disease and disease prevention

Question 1

Methods to break the transmission link of Dengue Fever

Answer 1

Spraying of pesticides / larvicidal oil to mosquito’s habitat
- Directly kill the larvae / adult mosquitoes, they cannot serve as vector
- Quickly put mosquito population down is short term
- Mosquitoes may develop resistance to pesticides
- Environmental contamination when pesticides leak to water bodies
- Pesticides are toxic to humans

Clearance of accumulated water in the neighbourhood
- Eradicate the breeding places of mosquitoes
- No adverse impacts on the environment
- Impossible to clear up all stagnant water

Question 2

Why antibiotics are not recommended for treating flu

Answer 2

• Flu is caused by virus which cannot be destroyed by antibiotics
• Indiscriminate use of antibiotics may lead to an increase in resistant bacterial strains

Question 3

Why the composition of flu vaccines has to be reviewed each year

Answer 3

• The flu virus may undergo mutation frequently to form new strains
• The epidemic strains may vary in different seasons