The hidden danger in your shower: what to know about Legionnaire's disease which has killed 3 people

Cosmopolitan

06-08-2025

New reports say three people have sadly died from Legionnaires' disease, a type of bacterial infection spread through water droplets, in New York and that more than sixty have fallen ill – leading to concerns that cases could become more widespread, including in the UK.
Legionnaires' disease is not limited to a specific location and in many cases does not become serious or life-threatening, but it's important to learn the symptoms associated with the disease and to track any outbreaks, explains Dr Naveed Asif, GP at The London General Practice.
"The situation [in New York] underscores the serious nature of Legionella, as it can cause significant illness and death," says Dr Asif. "This is a disease that can occur in the UK so monitoring and awareness is important."
Here's what you need to know about Legionnaires' disease, the symptoms associated with it, how it's spread and what treatments are on offer.
According to Dr Asif, Legionnaires' disease is an uncommon form of lung infection and best described as a form of pneumonia caused by the bacterium Legionella. "It presents in two forms: the more serious pneumonia and a milder illness known as Pontiac fever, characterised by muscle aches, headaches, and fever."
He adds that occasionally, Legionella can affect other organs, including the heart and skin. "It is important to note that Legionnaires' disease can be fatal if not treated promptly and effectively" but there are treatment options available, including antibiotics (administered through a hospital), oxygen and breathing support machines.
The GP explains that Legionella bacteria thrive in man-made water systems such as showers, sinks, hot tubs, water features, and cooling towers. "It can also be found in windshield wiper fluid in cars, particularly in tanks filled with water rather than genuine windshield cleaner," he adds.
Transmission occurs through inhaling contaminated droplets or swallowing contaminated water; person-to-person transmission is rare, confirming that Legionnaires' disease is not contagious. "The ease of spread is influenced by several factors: the concentration of bacteria in the water, the size of the droplets, and the susceptibility of the individual, which determines whether exposure will lead to illness," says Dr Asif, who also highlights that lifestyle factors can increase a person's risk of falling ill with Legionnaires' disease.
A high percentage of patients are smokers or diagnosed as having diabetes.
Symptoms to watch out for, as per Dr Asif and NHS guidance include:
"Symptoms typically manifest within two days to two weeks after exposure," points out the GP.
The NHS advises getting urgent medical help if you've had symptoms of Legionnaires' disease such as chest pain that comes and goes, feeling short of breath or coughing up blood. It also says to phone 111 or seek a GP appointment as soon as possible if you've had a cough that has continued for three weeks or more, and says it is important to tell medical staff where you have been in the previous weeks, such as if you have stayed in a hotel, spa or hospital.
The sooner Legionnaires' disease is identified, the easier it is to treat, says the expert. "[As well as] antibiotics, patients may also require oxygen for breathlessness, intravenous fluids for dehydration, or care for complications like sepsis," Dr Asif notes. "Hospitalisation is often necessary to monitor for severe complications, with intravenous antibiotics given initially, transitioning to oral antibiotics as the patient improves.
"In contrast, Pontiac fever usually does not require hospitalisation."
In a word, no – so while there's no need for major panic, it's still good to be mindful of symptoms in case you or a loved one starts displaying them. As per data available via the UK Health and Security Agency, there were 604 confirmed cases of Legionnaires' disease in England and Wales in 2023.
"A notable proportion of cases occurred in individuals over 60," says Dr Asif, adding that the incidence rate is around one per 100,000 (veering slightly higher in Wales and slightly lower in Scotland, with 54 cases reported last year). "The average number of cases has increased compared to pre-COVID-19 levels, potentially reflecting better testing and diagnosis. Seasonal peaks in cases are observed from June to October."
This article is not intended to be a substitute for professional medical advice or diagnosis. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
Jennifer Savin is Cosmopolitan UK's multiple award-winning Features Editor, who was crowned Digital Journalist of the Year for her work tackling the issues most important to young women. She regularly covers breaking news, cultural trends, health, the royals and more, using her esteemed connections to access the best experts along the way. She's grilled everyone from high-profile politicians to A-list celebrities, and has sensitively interviewed hundreds of people about their real life stories. In addition to this, Jennifer is widely known for her own undercover investigations and campaign work, which includes successfully petitioning the government for change around topics like abortion rights and image-based sexual abuse. Jennifer is also a published author, documentary consultant (helping to create BBC's Deepfake Porn: Could You Be Next?) and a patron for Y.E.S. (a youth services charity). Alongside Cosmopolitan, Jennifer has written for The Times, Women's Health, ELLE and numerous other publications, appeared on podcasts, and spoken on (and hosted) panels for the Women of the World Festival, the University of Manchester and more. In her spare time, Jennifer is a big fan of lipstick, leopard print and over-ordering at dinner. Follow Jennifer on Instagram, X or LinkedIn.