Question

Case-study: Proposed New Airport Runway for the Axe Stream Heights International Airport

Author: Ewan MacFarlane

Scenario (2b): In the past two months, members of the local community protest group, PEEPS, have continued to collect case-reports of illnesses attributed to close residential proximity to the airport. They now claim they have ‘uncovered’ a ‘cluster’ of 13 cases of cancer which they say are caused by exposure to pollutants and/or noise from the airport. Dr McGrimace and Ms Lightbody have reviewed these cases but can’t agree whether or not these cases actually are ‘disease cluster’ and/or if living near the airport is the cause. PEEPS has turned to you for advice.

Questions for discussion:

2b.1 ‘Disease cluster’ investigation

What is a ‘disease cluster’ and how should a suspected ‘disease cluster’ be investigated? Are there established processes for investigating a ‘disease cluster’?

What particular challenges are there for investigating a ‘disease cluster’ which is associated with environmental factors (as opposed to an occupational disease cluster)?

What information would you want to know about the cases?

How could you go about obtaining this information?

2b.2 ‘Disease cluster’ communication

Public communication and stakeholder involvement is particularly important when following-up a ‘disease cluster’ – how would you involve the public and stakeholders in this ‘cluster investigation’?

What principles of risk communication are relevant here and how would you ‘operationalise’ them in a situation like this?

What can be the consequences of poor stakeholder/public communication in a situation like this?What are some real examples of ‘botched’ public/stakeholder communication in past cluster investigations and/or other environmental health crises? What went wrong and why? What was done to remedy the situation and did it work?

Answer 1

Answer: Disease clusters may be defines as sometimes, a greater than expected number of cases of a disease occurs in a group of people living or working in the same area. This is called a disease cluster. In simple words, a disease cluster is an unusually high incidence of a particular disease or disorder occurring in close proximity in terms of both time and geography. Typically, when clusters are recognized, they are reported to public health departments in the local area.

Disease cluster’ be investigation can be done as it is aggregations of cases of a specific disease in space and/or time, in a community or an occupational group, at a level greater than expected by chance.

1. Identify investigation team and resources.
2. Establish existence of an outbreak.
3. Verify the diagnosis.
4. Construct case definition.
5. Find cases systematically and develop line listing.
6. Perform descriptive epidemiology/develop hypotheses.
7. Evaluate hypotheses/perform additional studies as necessary.
8. Implement control measures.

There were many reports of the ‘uncovered’ a ‘cluster’ of 13 cases of cancer which they say are caused by exposure to pollutants and/or noise from the airport. This is one of the symptoms of an outbreak of the disease. Once the investigator has estimated the degree of risk inherent in the situation under study, this information should be given to the community. Investigators also should be able to recognize the source of inevitable community suspicions (e.g., of deliberate delay and cover-ups) and demands (e.g., for the unrealistic allocation of resources and schedules).