Investigating Outbreaks Of Water bourne Diseases.  David Harper is now one of the leading experts in the field of Legionella, water borne contamination prevention and emergency response. David Harper

DAVID HARPER - Eng. Tech., M.I.H.E.E.M., F.W.M.Soc., HFSoPHE

M.C.I.P.H.E., M.I.I.E., M.A.S.E.E., M.I.E.T.

Public Health Consultant


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David Harper and the battle with Legionella

In 1979 there was an outbreak of Legionnaires Disease

(little known about at this time in the UK).

Unfortunately, there were three deaths in the first outbreak in 1979.

David Harper investigated the cause and the eradication of this outbreak of Legionnaires Disease.

Thankfully the source was successfully identified and found to be the cooling tower, the tower was removed and an air cooler was put in its place.


David Harper

However, the following year 1980 another outbreak of Legionnaires Disease hit Kingston Hospital, and this was identified to the hot water calorifier system within the main surgical block - the first in the world.

This was successfully eradicated.

While this was being carried out, the Kingston Controls were evolved which were the forerunners’ of the now A.C.o.P. L8 document, which are now used as a standard by the building users in hospitals and other complexes worldwide.

These controls are now being revamped by other but, in essence, are still the same.

While carrying out the work, he contracted the disease himself and spent a week and a half in the intensive care unit of his own Hospital.

Subsequently, after nine months, he recovered fully and return to work.

Due to the Government concern about the potential size of the problem within the UK, which was unknown at the time, he was seconded to the Public Health Laboratory Services in the Communicable Disease Surveillance Centre (CDSC) now HPA, to carry out a major site investigation to take water sample and carry out what was then known as a hazard assessment but now known as a risk assessment and to inspect the water systems within a range of building from office building to oil platforms.

Legionnaires' disease is an acute respiratory infection caused by inhalation of the bacterium legionella neumophila in its aerosol form, early symptoms of the disease are flu-like and may include muscle ache, dry cough, diarrhoea and fever. In some patients, the symptoms may progress to pneumonia, and the disease is fatal in 10 to 15 per cent of cases in the general community.

The risk of infection is greater in hospitals, however, where the disease can more readily infect the elderly and the immuno-suppressed (such as cancer and transplant patients).

Underlying illness is a major risk factor for acquisition of the disease and, as the major mode of transmission is aspiration, patients with chronic lung diseases and those requiring general anaesthesia are also at greater risk. Mortality in such groups can reach 40 per cent.

The hot water systems of healthcare facilities have been identified as the most frequent source of nosocomial legionella. Adding to the urgency of the problem, up to 95 per cent of legionella cases in the UK go undiagnosed.