Pneumococcus: An Infectious Disease Tornado

There is something majestic and sublime about watching a ferocious infectious disease at work, the elegance of a microscopic creature ravaging something incalculably larger than itself. I recently witnessed a cause of overwhelming post-splenectomy infection due to pneumococcus. For those who have witnessed this infection, it is truly jaw-dropping in its ferocity.

Sometimes being the equivalent of a tornado-chaser with infectious diseases, causes me to reflect on the host-microbe interaction and how the precarious balance can be tipped allowing a microbe to damage the host.

The spleen is a crucial organ of the immune system and its absence places one at a severe disadvantage when it comes to fighting off infections. The big three of post-splenectomy infections are the encapsulated Hemophilus influenzae (type B), pneumococus (Streptococcus pneumoniae), and meningococcus (Neisseria meningitidis), all of which are targeted via vaccination before splenectomy is performed (if planned) or shortly after (if unplanned). Vaccine immunity is not absolute and can wane, leading to enhanced vulnerability.

In many of these cases mortality rates remains very high even in the face of antibiotics and state of the art critical care, highlighting the evolutionary and survival value of a fully functioning immune system.

Be thankful mammals evolved spleens, yours probably saved your life more times than you can count.