10.1.4—Prevention and control

Infectious-disease prevention and control work best when the measure targets the pathogen, route or host susceptibility involved. Feasibility also depends on biological conditions, social organisation and available resources, so one measure is not equally effective everywhere.

• Cholera: sewage treatment and clean, chlorinated piped water reduce contamination of the water/food route; vaccination can help in areas where cholera is common. Oral rehydration supports affected people, while monitoring and antibiotics in severe cases are control measures rather than route prevention.
• Malaria: insecticides, reducing breeding sites where feasible, biological control of larvae, insecticide-treated bed nets and reducing exposed skin target the Anopheles vector or human–vector contact. Preventive drugs, rapid diagnosis, effective treatment and vaccines are additional tools, but resistance, side effects, cost and mosquito breeding in small water bodies limit universal control.
• Tuberculosis: BCG vaccination reduces susceptibility; contact tracing and testing identify exposed cases. Testing cattle, pasteurising milk and properly cooking meat address M. bovis, while overcrowded housing increases the social opportunity for droplet spread.
• HIV/AIDS: screened blood, sterile needles, condoms/femidoms/dental dams and education reduce opportunities for infected body-fluid exchange. Testing, contact tracing, antiretroviral drugs and treatment of HIV-positive mothers and babies support control; long asymptomatic stages and unequal access to testing, drugs and safer alternatives affect feasibility.

The same intervention category can act at different points: vaccination changes host susceptibility, sanitation or barriers reduce exposure, vector control removes a transmission opportunity, and diagnosis or treatment reduces the number or duration of infectious cases. Layered measures are useful because biological resistance, infrastructure, behaviour and funding can weaken any single control.

Control is not a list of universally interchangeable actions: match the measure to the disease route and local constraints. This card synthesises prevention, diagnosis and treatment choices; the neighbouring cards establish the pathogen and transmission routes, so this card does not redefine those routes or add unlisted drug mechanisms or policy details.