Latest Infectious Disease News
As offices, shops, and restaurants sit unused during the COVID-19 pandemic’s social distancing measures, some experts worry another deadly microbial attacker may be literally waiting in the pipeline: Legionella pneumophilia, the bacteria that causes Legionnaires' disease.
Researchers at the University of Pittsburgh in July announced they were working on a study to determine how to stop Legionella at the faucet through silver-impregnated antimicrobial showerheads and fixtures. Their work takes on extra importance as managers across industries and disciplines figure out how to reopen their facilities safely.
"While the context of our proposed research is showers in homes, offices, healthcare facilities, and gyms under normal operation, the COVID-19 pandemic introduces a new relevance to our project," said lead researcher Leanne Gilbertson, assistant professor of civil and environmental engineering at Pitt, in a press release.
Legionella lives in water systems and standing water. Allowing water to stagnate in the pipelines of buildings through disuse means residual treatment chemicals like chlorine have a chance to dissipate. As a result, harmless small populations of different kinds of bacteria found in all water supplies have an opportunity to bloom in the pipes during the shutdown, becoming potentially dangerous as people re-occupy vacant buildings, experts say.
Incidence of Legionnaires' or legionellosis have increased by 900 percent from 2000 through 2018, the latest statistics available from the CDC. In the year 2000, the U.S. saw just over 1,000 cases. Eighteen years later, CDC data show more than 10,000 reported Legionella infections.
Inhaling the contaminated vapor from a flushing toilet or the water from a faucet can be enough to contract the infection, a form of bacterial pneumonia.
This is not an abstract threat; a Legionella–contaminated hot tub display at a September state fair in North Carolina sickened 141 people, sent 94 to the hospital and killed four, according to Asheville’s ABC News 13. This was the largest U.S. outbreak in recent history, according to News 13.
The CDC can’t say whether rising rates stem from an increase in Legionella bacteria in the environment, whether Americans are becoming more susceptible because of a rise in other chronic conditions that weaken their immune systems or whether the increase is simply due to better reporting.
The increase may result from a combination of these factors, the CDC states.
How Does Legionella Infect Water Sources?
The water municipal utilities pump into your home is not sterile.
There are low populations of mostly harmless bacteria. The chlorine used to purify the water keeps these microbes in check. The chlorine evaporates out of water readily, but it lingers in the water system as fresh is continually run through the pipes, characteristic of normal use, explained Sarah Haig, another civil and environmental engineering professor on the silver-faucet study.
"Typically, the drinking water entering buildings contains a disinfectant residual, such as chlorine, to help prevent and reduce microbial growth," she said in the release. “However, changes in water chemistry, building fixtures and building operation, like the long periods without water use (stagnation) recently observed across the world during the COVID-19 pandemic will have unexpected consequences on building water quality."
The Pitt project will study how effective silver antimicrobial fixtures are in killing Legionella at the tap. The National Science Foundation last month awarded the team $330,000 to find out whether such fixtures are effective, or if they are effective, whether they induce antibiotic resistance, according to the Pitt press release.
"Water fixtures containing silver are believed to eliminate bacteria due to the antimicrobial properties of this heavy metal; however, heavy metal exposure is also known to transform some bacteria into antibiotic resistant forms," said Gilbertson.
How Do You Know if You Have Legionnaires' Disease?
People of any age can develop Legionnaires' disease, but the illness most often affects middle-aged and older people, particularly those who smoke cigarettes or have chronic lung disease, as these individuals have a greater likelihood of developing any respiratory illness, writes MedicineNet author George Schiffman, MD, FCCP.
People at an increased risk for Legionnaires' disease also include people whose immune systems are suppressed by diseases and conditions such as cancer, kidney failure requiring dialysis, diabetes, or AIDS. Those who take medications that suppress the immune system are also at risk including those chronically on steroids, Dr. Schiffman said.
Pontiac fever, a variation of Legionnaires', most commonly occurs in healthy people, Dr. Schiffman said.
Schiffman stressed that Legionella causes few symptoms that are unique compared with other types of pneumonia. If you recognize the following symptoms, you should seek medical attention, he said:
- Patients with Legionnaires' disease usually develop a fever, chills, and a cough.
- The cough may either be dry or produce sputum.
- Some patients with Legionnaires' disease also have muscle aches, headache, tiredness, loss of appetite, and occasionally diarrhea.
- Legionnaires' disease can cause a severe pneumonia, seriously affect breathing, and even lead to respiratory failure and adult respiratory distress syndrome (ARDS).
- In some cases, the heart rate is slower than expected for the degree of fever.
- There are no specific symptoms that directly identify Legionnaires' pneumonia.
- Legionnaires' pneumonia presents in a manner similar to Chlamydia pneumonia and Mycoplasma pneumonia, so-called atypical pneumonias (previously referred to as "walking pneumonia").
- These are referred to as atypical because the associated symptoms and signs are unlike typical pneumonia (as characterized by Streptococcus pneumonia), which involves spiking high fevers, sudden onset, cough, and purulent sputum and often chest pain and a localized infiltrate on chest X-ray.
- People with Pontiac fever experience a self-limiting influenza-like illness with fever, chills, headache, and muscle aches but, by definition, do not have pneumonia.