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Sudden infant death syndrome linked to Pneumocystis infection

November 06 2012

The cause of sudden infant death syndrome (SIDS) is not known. While some cardiac and metabolic disorders are occasionally found, most babies that die of SIDS are apparently in the best of health, often between the ages of 2 and 5 months old, and are found dead.  New work from Santiago, Chile, Pneumocystis was found frequently (82%) in SIDS babies where it was associated with an increase in mucus production. Pneumocystis is acquired early in life from other humans. What is surprising is the association of Pneumocystis infection with increased mucus production, a marker inflammation, which causes narrowed airways and potentially airway collapse leading to death.

The work was published online in the prestigious journal Clinical Infectious Diseases from the Instituto de Ciencias Biomédicas, Facultad de Medicina Universidad de Chile, Santiago, Chile together with colleagues from Lille in France and University College in London. Link to Article 

Dr Vargas said of his team's work; "The common fungus Pneumocystis increases pulmonary mucus like other airway irritants, increasing the workload of the airway. When this happens in the small developing airways of infants, the mucus overload may lead to airway collapse as a probable mechanism for some SIDS cases. As Pneumocystis is commonly present and is potentially preventable, unlike most viruses, reduction in SIDS deaths may be possible.'

Commenting on this work for LIFE, Professor Colombo from Sao Paulo said; “This meticulous work from a strong international team is potentially a great step forward in understanding SIDS.”

The results show that lung tissue biopsies from babies who die of SIDS need to be processed differently to detect Pneumocystis. This is an important step because traditional methods only detected Pneumocystis in a third of cases.