Tuberculosis (TB), an ongoing infection control concern in long-term care, is more likely to be spread by breathing than by its distinctive cough, according to a new study that may contradict decades of clinical teaching.
The findings, which are yet to be peer-reviewed, suggest that the long-standing strategy of testing and treating only symptomatic TB patients may not be enough to prevent spread of the highly contagious disease, according to investigators from the University of Cape Town in South Africa. The study was made possible by a novel technology that can detect bacteria in aerosols, various news sources reported.
Much like SARS-CoV-2, the virus that causes COVID-19, the bacteria that causes TB can become airborne on tiny respiratory droplets. In the current study, fully 90% of infectious droplets were expelled by breathing alone, researchers reported in an October conference presentation.
“This leaves room for extensive [Mycobacterium tuberculosis] transmission prior to treatment seeking” and suggests that the disease needs to be diagnosed earlier in its course, the lead researcher told news outlet AFP. But this begs the question of how these patients would be identified, he added.
TB in long-term care
Outbreaks of TB in long-term care facilities can be insidious, as older adults are more likely to harbor latent disease acquired earlier in life and more likely to be susceptible to contracting it due to a weakened immune system. TB disease incidence rates have declined in the United States, but the number of people with latent TB infections — which can later switch to active disease — continues to grow, studies have found.
In 2014, 2.2% of TB cases were among residents diagnosed in long-term care facilities, CDC researchers reported. This number will likely become increasingly disproportionate as the number of adults aged 65 and older grows, they estimated.
Not only is transmission a concern, but TB can be life threatening if not caught and treated early enough, experts caution. That’s why long-term care staff, residents and other vulnerable populations should be screened for latent TB infections, according to the US Preventive Services Task Force and the Centers for Disease Control and Prevention.
“Concentrations of elderly persons, many of whom are infected with tubercle bacilli and some of whom are immunosuppressed, create high-risk situations for tuberculosis transmission,” reported advisers to the Centers for Disease Control and Prevention. Nursing home employees also are at increased risk when compared with other employed adults, the experts stated.
Super-spreaders and symptoms
Like some patients infected with COVID-19, some TB patients may become super-spreaders, transmitting the disease to many people they come in contact with, while others may transmit the disease to a few individuals only, the New York Times reported.
TB symptoms can include a progressively worsening cough lasting more than two weeks, fatigue, weakness, weight loss, night sweats, fever, chills and chest pain. The disease is treatable and curable, but may require the use of several medications over the course of six to nine months for complete eradication, or longer if the strain is drug resistant.
The current study was presented at the 52nd Union World Conference on Lung Health.
