Researchers find triple as many Legionnaire's cases as previously reported

June 10, 2019

The first New Zealand-wide study of the burden of Legionnaire's disease has found triple the number of cases of this form of pneumonia than previously reported.

The study, led by University of Otago, Christchurch Professor David Murdoch, has just been published in the Lancet Infectious Diseases. It gives the first accurate picture of the burden of the disease in New Zealand, but has international implications as few places routinely test for the potentially deadly - and preventable - bacteria.

The researchers arranged for people hospitalised with pneumonia from almost all of New Zealand during one calendar year to have a specialised test that detects legionella bacteria. Three times the number of cases were diagnosed compared with the average number of cases confirmed over each of the previous three years.

Specifically, the researchers found:Professor Murdoch, a clinical microbiologist and researcher, says a special test called the polymerase chain reaction (PCR) is the best way to diagnose Legionnaires' disease as chest x-rays or other tests cannot differentiate between this and other forms of pneumonia. The disease requires different treatments from other types of pneumonia. The sooner the infection is treated with bacteria-specific medication, the better the prognosis, he says.

"This research shows the incidence of Legionnaires' disease in New Zealand is much higher than previously identified. Indeed, we have the highest reported incidence in the world. The research also supports the routine use of the PCR test to detect and ensure access to appropriate treatments,'' Professor Murdoch says.

The results are relevant to other countries as the bacteria causing Legionnaires' disease is present internationally but few countries have routine testing in place, Professor Murdoch says.

The study identified the most common form of bacteria causing the disease in New Zealanders was Legionella longbeachae (in 63% of cases). This strain is found in soil and composted plant material, and people at greatest risk are those involved in gardening activities.

To get their results, the research team tested all respiratory samples from patients with pneumonia admitted to any of the 20 participating hospitals between May 2015 and May 2016. During the year a total of 238 cases were identified, or 5.4 cases per 100,000 New Zealanders. This was three times the rate expected based on the number of people diagnosed in the preceding three years. Of the 238 cases, 15 died within 90 days of diagnosis and 38 cases required treatment in an intensive care unit (ICU).

Professor Murdoch says the research was possible because of the involvement of staff and laboratories from 20 hospitals and 17 different District Health Boards. It is unusual for this degree of collaboration on research projects, he said.
-end-
The research was funded by the Health Research Council of New Zealand (HRC).

HRC chief executive Professor Kath McPherson says the study demonstrates the vital importance of accurate data. "Without robust data, we can completely underestimate the extent of a problem and make uninformed decisions, and in health that can have extremely negative consequences. It is very pleasing to see this huge collaborative effort result in definitive findings that should inform practice and policy throughout our country and internationally where such work has not been done."

To interview Professor Murdoch email kim.thomas@otago.ac.nz

University of Otago

Related Pneumonia Articles from Brightsurf:

Vaccine proves effective against the most severe type of pneumonia
A pneumococcal vaccine was effective at protecting children in Laos against the most severe type of pneumonia, a new study has found.

Osteoporosis treatment may also protect against pneumonia
A recent study published in the Journal of Bone and Mineral Research found that nitrogen-containing bisphosphonates (N-BPs) such as alendronate, which are widely used to treat postmenopausal osteoporosis, are linked with lower risks of pneumonia and of dying from pneumonia.

Elderly patients with pneumonia twice as likely to die as those with broken hips, yet underestimate the danger of pneumonia
Elderly patients who are hospitalised with pneumonia are twice as likely to die as those hospitalised with hip fractures -- yet many elderly people fail to accurately assess their risk of pneumonia, concludes research due to be presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

Pneumonia recovery reprograms immune cells of the lung
Researchers have determined that after lungs recover from infection, alveolar macrophages (immune cells that live in the lungs and help protect the lungs against infection) are different in multiple ways and those differences persist indefinitely.

Skin and mucous membrane lesions as complication of pneumonia
Painful inflammatory lesions of the skin and mucous membranes may occur in children who develop bacterial pneumonia.

Vaccine reduces likelihood of severe pneumonia
A new study has found severe pneumonia decreases by 35 per cent in children who receive a vaccine against a pneumonia-causing bacteria.

Bacteria in pneumonia attack using bleaching agent
Research shows that bacteria use hydrogen peroxide to weaken the immune system and cause pneumonia.

Many kids with pneumonia get unnecessary antibiotics, chest X-rays
Preschool children with community-acquired pneumonia often receive unnecessary tests and treatment at outpatient clinics and emergency departments, according to a nationally representative study led by Todd Florin, M.D., MSCE, from Ann & Robert H.

Certain psychiatric drugs linked with elevated pneumonia risk
A review of published studies indicates that use of benzodiazepines and benzodiazepine related drugs (BZRDs), which are prescribed to treat various psychiatric diseases, may increase the risk of pneumonia.

Bacterial pneumonia far more dangerous to the heart than viral pneumonia, study finds
Heart complications in patients diagnosed with bacterial pneumonia are more serious than in patients diagnosed with viral pneumonia, according to new research.

Read More: Pneumonia News and Pneumonia Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.