The Dedicated Entomologist That Let A Flea Live Inside Her Own Body For Science

The arthropod species that is officially known as Tunga penetrans is more commonly known as a chigger flea, sand flea, chigoe, jigger or chigger. These fleas are native to the Caribbean islands and they are historically notable for infecting the crew of the Santa Maria after it wrecked on the island of Haiti. Columbus and the rest of his crew made the bad decision to bring this flea species back to Europe with them. Now, chigger fleas are endemic on the European continent, and they remain common to this day as stowaway arthropods on shipping vessels that travel between South America and Europe. This is why chigger fleas occasionally burrow beneath the skin of people walking barefooted on the sand of European beaches. However, chigger flea infections are far more common in Central and South America where they are considered a serious public health risk. Once a chigger flea creeps beneath the skin of its mammalian host, more female chigger fleas are attracted to the host, resulting in an infection known as tungiasis. Eventually, an affected person can acquire numerous chigger fleas beneath the skin, causing severe pain and serious medical issues. Considering this well known information, it is all the more impressive to learn that a dedicated entomologist allowed herself to become infected with a chigger flea solely to observe its development below the surface of her skin.

Marlene Thielecke, a Ph.D. student at Charité University Medicine in Berlin, was studying chigger fleas in Madagascar in an effort to develop a treatment for tungiasis infection. One day Thielecke spotted a chigger flea beneath the skin on her foot, so she left it in as a convenient method of observing how the flea reproduces. Ever since chigger fleas were first described, researchers have debated over the manner in which these arthropods reproduce. It was not known whether males impregnate females that are already embedded in skin, or if females are impregnated before becoming embedded in its host’s skin. After several days, the flea in her foot did not die, nor did it produce eggs. This indicated to Thielecke that the female was waiting for a male suitor while embedded within her own skin, thus solving the mystery. As it turned out, Thielecke was correct, and this method of reproduction makes sense from an evolutionary perspective, as males can impregnate a greater amount of fertile females by accessing skin that already contains female fleas. Also, since female fleas gather below skin in clusters, more females can become impregnated, as this saves males from having to expend energy searching for individual female fleas in the wild.

Would you allow yourself to risk infection if it meant uncovering the answers to a long-running scientific mystery?