What is Pontiac Fever?

Pontiac Fever is the acute non-pneumonic form of Legionella infection. It gets its name from the epidemic flu-like illness that occurred in a Health Department building in Pontiac, Michigan in 1968.

Studies in 1978 confirmed that this illness was caused by Legionella pneumophila bacterium. Since then several outbreaks have been described involving Legionella pneumophila serogroup 1 and 6, further studies have shown the involvement of Legionella feeleii. A study in 1998 showed the cause was Legionella micdadei

It has not been fully explained why Legionella infections should manifest itself either as Legionella pneumonia, often with a low attack and significant mortality, or as Pontiac Fever, with a very high attack rate and no mortality.

Isolates of Legionella pneumophila associated with both types of illness have shown no difference in virulence.

In the UK the equivalent illness to Pontiac Fever is Lochgoilhead Fever. Analysis of case histories from 187 people who had visited a hotel and leisure complex in Lochgoilhead, a village on the west coast of Scotland, indicated that 170 had had an acute illness characterised by headache, fatigue, arthralgia, myalgia, cough, and breathlessness. These symptoms were consistent with Pontiac fever-like illness. Legionella micdadei was isolated from the leisure complex whirlpool spa at the time.

The attack rate of Pontiac Fever is very high with 95% of all people exposed falling ill in the original Pontiac case. The incubation period varies from 4 to 66 hours but is usually 36 to 48 hours. The symptoms represent as flu-like which resolve spontaneously within 2 to 5 days. One unusual feature of the original case was that recurrent illness in 14% of employees occurred when re-exposed to the building within a few days of recovering from the original illness.

The number of cases of Pontiac Fever or Lochgoilhead Fever do not appear to be recorded due to the symptoms being similar to flu so unless you are involved in a Legionnaires’ disease investigation it is unlikely you would find out whether your flu was indeed Pontiac or Lochgoilhead Fever.

All the same management techniques and processes for managing Legionella bacteria in water systems should be employed to prevent Pontiac and Lochgoilhead Fever.

Collaton Consultancy Limited are a specialist consultancy offering technical advice on Legionella, Pseudomonas and water treatment. We also act as Authorising Engineer (Water) in healthcare sites and as Expert Witnesses. We also offer both online and face to face training in a host of subjects.

More information can be found on the following websites:



1 Comment

  1. Great blog by Nigel Richardson, looking forward to more from you soon!

    Expert information and a must read, keep them coming Sir!


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