What are the other Names for this Condition? (Also known as/Synonyms)

• Non-Pneumonic Legion Fever
• Non-Pneumonic Legionella Infection
• Non-Pneumonic Legionellosis

What is Pontiac Fever? (Definition/Background Information)

• Pontiac Fever is a mild flu-like illness caused by bacteria belonging to the genus Legionella, the most common being Legionella pneumophila that is responsible for a vast majority of the cases
• The same bacteria could also cause a severe form of pneumonia (lung infection) called Legionnaire’s disease, which is a rapidly fatal disease. These two illnesses are collectively known as Legionellosis (diseases caused by Legionella). The bacteria can also spread from the lungs to other parts of the body
• Pontiac Fever is known to occur globally, and older adults and those with weak immune systems have a higher susceptibility risk. The exact burden of the disease is unknown as it is a mild illness which usually resolves within a week without any treatment and may go undiagnosed or misdiagnosed, and therefore, go unreported
• The causative bacteria occur worldwide and grow and multiply within single-celled organisms (e.g., amoebae) in a variety of places, such as damp soil and natural freshwater reservoirs (lakes, streams, and rivers), but are generally not present in sufficient numbers to cause infection
• Artificial human-made settings that store and use stored water can provide a favorable environment for bacterial multiplication, causing a spread of bacteria through aerosolized contaminated water. These can include hot tubs, decorative fountains, domestic and industrial potable water, heating, ventilation, and air-conditioning systems, among others
• Pontiac Fever has a high attack rate of more than 90% i.e., over 90% of the exposed individuals develop the illness. Flu-like symptoms appear within a few hours to 3 days after exposure to infection. This may include fever and chills, fatigue, body ache, joint pain, cough, and loss of appetite. It often goes undiagnosed in a majority of the cases as it resolves spontaneously
• Pontiac Fever is a mild self-limiting illness that does not involve the lungs. It usually resolves in less than a week without any complications being noted. The healthcare provider may undertake to treat the symptoms; and generally, antibiotics are unnecessary for treating the condition
• There is no vaccine currently available against Legionella infection. However, infection can be prevented by taking precautionary measures for preventing bacterial growth in the human-made water systems through routine cleaning and disinfection.

Who gets Pontiac Fever? (Age and Sex Distribution)

• The prevalence of Pontiac Fever is unknown, but it has been reported from several parts of the world
• The disease can occur in individuals of all ages, but those who are 50 years or older are reported to be more at risk of contracting the infection
• Both male and female genders are prone to the disease
• All racial and ethnic groups are at risk for the infection

Although the bacterial infection can occur throughout the year, the bulk of cases are reported in summer and early autumn (fall).

What are the Risk Factors for Pontiac Fever? (Predisposing Factors)

Risk factors for Pontiac Fever include certain personal factors which make an individual more susceptible to infection and environmental factors which increase the risk of contamination of water systems with Legionella, including devices that lead to aerosolization of contaminated water.

• Factors which make one susceptible to Legionella infection and Pontiac Fever include:
  • Older age (50 years or more)
  • Smoking
  • Chronic lung disease such as emphysema, chronic obstructive pulmonary disease (COPD), and asthma
  • Diabetes, kidney disease, liver failure, cancer, and other chronic illnesses
  • Weakened immune systems such as due to HIV infection and AIDS
  • Taking steroids or other drugs which suppress the immune system, e.g., following organ transplantation
• Factors that favor the multiplication of Legionella in manmade water systems, such as hot tubs, decorative fountains, domestic and industrial potable water, heating, ventilation, and air-conditioning systems among others, may include:
  • Poor control of water temperature and pH
  • Poor design and/or poor maintenance
  • Intermittent water supply and stagnation, or low rates of water flow
  • Inadequate staff training to manage water systems
• Travelers are at increased risk as hotels, resorts, and cruise ships also have large, complex water distribution systems and aerosol-generating devices
• Hospitalized patients or those in nursing homes are at increased risk because of the following factors:
  • Hospitals and long-term care facilities have large, complex water systems
  • These are (more) susceptible populations
  • Medical equipment may harbor the infection

Home and car air-conditioning units that do not use water are not risk factors for Pontiac Fever.

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Pontiac Fever? (Etiology)

Pontiac Fever is caused by bacteria belonging to the genus Legionella. More than 80% of the cases are caused by the species Legionella pneumophila. These bacteria are naturally found in freshwater and multiply rapidly in warm water.

• They are also known to survive in damp soil as well as several other environments, such as artificial man-made settings which store water and provide favorable environment for the bacterial growth, such as hot tubs, decorative fountains, domestic and industrial potable water, heating, ventilation, and air-conditioning (HVAC) systems, and cooling towers (used in large buildings)
• The infection is acquired by breathing in bacteria in the aerosols (mist) generated from contaminated water. In rare cases, the infection can also occur while drinking, by accidental aspiration of the contaminated water into the windpipe

However, Pontiac Fever usually does not spread from one individual to another.

What are the Signs and Symptoms of Pontiac Fever?

More than 90% of the individuals exposed to the source of infection develop the clinical illness. The signs and symptoms of Pontiac Fever become apparent in a few hours to 3 days (most commonly 24-48 hours) after being exposed to the bacterium.

The clinical picture consists of non-specific flu-like symptoms and may include:

• Low to high fever
• Chills
• Weakness and tiredness
• Headaches
• Body pain
• Muscle or joint pain
• Decreased appetite
• Dry cough
• Nausea and vomiting
• Diarrhea

In contrast to Legionnaire’s Disease, Pontiac Fever does not involve the lungs, and therefore, it is marked by an absence of pneumonia.

How is Pontiac Fever Diagnosed?

Pontiac Fever is non-specific in presentation and goes away within a week without any treatment. Therefore, it often goes undiagnosed or may be clinically misdiagnosed as flu.

• The diagnosis of Pontiac Fever is most often made when there are other cases of Legionella infection which have been confirmed by laboratory tests
• Urine test to detect bacterial protein antigen, known as urinary antigen test, or blood test to detect antibodies can be used to diagnose the infection. But a negative result does not rule out the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Pontiac Fever?

Pontiac Fever usually resolves completely within a week without any short-term or long-term complications being noted.

How is Pontiac Fever Treated?

• Pontiac fever is a mild illness that goes away on its own within a week. Antibiotic treatment is not necessary, and therefore not recommended
• A nutritious diet, rest, and plenty of fluids to maintain hydration are sufficient for complete recovery
• Symptomatic treatment can be given to relieve fever and pain

How can Pontiac Fever be Prevented?

Currently, no vaccines are available to prevent Pontiac Fever.

• To decrease susceptibility to the condition, cessation of smoking is recommended
• Preventing infection by Legionella may involve:
  • Proper maintenance of the water systems to prevent the growth of bacteria
  • Taking proper steps to eliminate the bacteria if contamination is found
  • Routine cleaning and disinfection of water systems
  • Whirlpools, hot tubs, among other water-based systems need to be meticulously cleaned and disinfected, prior to and after use

What is the Prognosis of Pontiac Fever? (Outcomes/Resolutions)

• Pontiac Fever is a mild self-limiting illness which resolves fully in less than a week without any need for antibiotic treatment
• The outcomes are generally excellent with no short-term or long-term complications being noted

Additional and Relevant Useful Information for Pontiac Fever:

• Pontiac Fever is named after the Pontiac city in Michigan, USA, where the first outbreak of Pontiac Fever was described
• Legionnaire’s disease is named after an outbreak of severe pneumonia (lung infection) that occurred in the attendees of the Philadelphia convention of the American Legion in 1976

The following article link will help you understand Legionnaire’s disease:

https://www.dovemed.com/diseases-conditions/legionnaires-disease/