Mary Ingalls Blindness: Scarlet Fever May Not Have Been The Cause

Little House fans may be surprised to hear that Mary Ingalls’ blindness may not have been caused by scarlet fever, as the beloved book series led readers to believe.

A new study shows that a brain infection is most likely the medical event that blinded Mary in 1879 at the age of 14. Mary was a central figure in the series of books which chronicled the lives of Laura Ingalls Wilder and her family during the 1800’s.

CBS News writes that the Little House series, based on Wilder’s letters and unpublished memoir, detailed older sister Mary’s tragic loss of sight. At the time it was assumed that the family’s bout with scarlet fever resulted in the girl’s blindness.

A new study, published on February 4 in Pediatrics, finds that the eldest Ingalls girl was probably the victim of viral meningoencephalitis. The virus causes both the brain and the membranes which protect the central nervous system to become inflamed.

Dr. Beth Tarini, a pediatrician and researcher at the University of Michigan, is one of the study’s authors. Having read about Mary Ingalls’ blindness she decided to get to the bottom of its cause:

“Since I was in medical school, I had wondered about whether scarlet fever could cause blindness because I always remembered Mary’s blindness from reading the Little House stories and knew that scarlet fever was once a deadly disease. I would ask other doctors, but no one could give me a definitive answer, so I started researching it.”

According to The Associated Press, Tarini conducted an analysis of historical documents, biographical records and other materials to determine if scarlet fever was in fact the culprit.

The research produced no valid findings in favor of the scarlet fever theory. None of the documents reviewed reflected the presence of signature side effects related to the illness.

Descriptions of the symptoms the Mary suffered from were found to match those caused by brain infections such as viral meningoencephalitis. The study also uncovered an 1889 register which listed “brain fever” as the cause of the girl’s blindness.

Researchers can only speculate as to why the books seemed certain that scarlet fever led to the loss of Mary’s eyesight. Sarah S. Allexan, one of the study’s authors and a medical student at the University of Colorado, spoke about a possible scenario:

“Laura’s memoirs were transformed into the Little House novels. Perhaps to make the story more understandable to children, the editors may have revised her writings to identify scarlet fever as Mary’s illness because it was so familiar to people and so many knew how frightening a scarlet fever diagnosis was.”

Are you one of the many readers who followed the story of Mary Ingalls’ blindness in the Little House series?