Helminth infections predispose mice to pneumococcal pneumonia but not to other pneumonic pathogens

Area of Science:

• Immunology
• Infectious Diseases
• Parasitology

Background:

• Pneumonia remains a leading cause of childhood mortality globally.
• Helminth infections are endemic in many developing regions, overlapping with high rates of pneumococcal disease.

Purpose of the Study:

• To investigate the impact of helminth coinfection on susceptibility to Streptococcus pneumoniae infection.
• To determine if helminth infection predisposes to severe pneumococcal pneumonia.

Main Methods:

• Mice were chronically infected with helminths (Taenia crassiceps or Heligmosomoides polygyrus).
• Infected and control mice were challenged with Streptococcus pneumoniae.
• Bioluminescent imaging and lung titers were used to assess pneumonia severity.
• Challenges with influenza virus, Staphylococcus aureus, and Listeria monocytogenes were performed to assess specificity.

Main Results:

• Helminth-infected mice exhibited a higher rate and severity of fatal pneumonia upon Streptococcus pneumoniae challenge.
• This increased susceptibility was specific to S. pneumoniae, as other pathogens did not cause increased morbidity.
• Anti-helminthic treatment in H. polygyrus-infected mice reversed the heightened susceptibility to pneumococcal pneumonia.

Conclusions:

• Helminth coinfection predisposes mice to fatal pneumococcal pneumonia by enhancing bacterial outgrowth in the lungs and bloodstream.
• These findings have significant implications for pneumonia prevention and treatment strategies in regions with high helminth and pneumococcal disease prevalence.