When a case of any notifiable disease was reported to the HPA’s local Health Protection Units (HPUs), staff would provide public health advice to the reporting doctor. This included advice on the length of time to isolate the ill person, whether people in close contact with the ill person required vaccination, or whether people in the same household needed antibiotics to prevent further spread of the infection. HPU staff would also advise on which samples should be taken and ensure that they were delivered to the correct HPA laboratory for testing. Databases would be searched to check whether the case could be linked to others which may have indicated a potential outbreak.

Outbreaks

An outbreak of an infectious disease is defined as:

• An incident in which two or more people with a similar illness are linked in time and place.
• A greater than expected rate of infection compared with the usual background rate for the place and time. 
• A single case for certain rare diseases such as diphtheria, botulism, rabies, viral haemorrhagic fever or polio. 
• An event involving contamination of food or water.

Outbreaks are detected by the HPA, Local Authorities or microbiologists at a local or national level. Each organisation has its own procedures for surveillance, detection and control and, as soon as it becomes apparent that an outbreak may exist, immediate contact between these organisations is established. They consider the facts available and will determine whether or not an outbreak does exist.

Often it is necessary to collect further evidence before outbreak decisions can be made. Key objectives in this initial stage are to determine:

• Whether a problem exists
• The nature and extent of the outbreak
• What immediate steps need to be taken to:
  • Identify those who are ill
  • Ensure they receive appropriate care
  • Identify those at risk
  • Control the source
  • Prevent the infection spreading

An Outbreak Control Team (OCT) is established if an outbreak has one or more of the following:

• Immediate or continuing infectious disease health hazard to the population
• One or more cases of serious communicable disease
• Large numbers or numbers greater than expected
• A large geographical area
• Vulnerable groups affected e.g. the elderly, children

The OCT brings together key clinical staff, microbiologists, epidemiological expertise, environmental health and other Local Authority staff, and any other relevant agencies (for example the Food Standards Agency and Defra), to find out the nature and extent of the outbreak and put in place effective measures to control it. This includes ensuring that ill people receive appropriate treatment, samples are tested in the laboratory, possible sources such as foods are removed from sale and restaurants or other food outlets thought to be the source are closed until safe practice can be re-established.

Incidents

Incidents may be defined as the exposure of one or more people to a substance (chemical/radiological/biological) which may damage health. They are handled in a similar way to outbreaks by convening a team which, in addition to public health expertise, has scientific expertise in the particular hazard. The team would provide incident specific advice on how to decontaminate people, whether specific treatment is required and the measures needed to prevent other people suffering the same exposure. The team would also contribute advice on how to clean up any substance in the environment safely.