Human body lice could harbor the plague and spread it through biting
Special glands in the head can house plague bacteria
![Image shows the head and upper appendages of a glowing green human body louse. Two red dots on either side of the head indicate the louse carries Yersinia pestis, the bacterium that causes plague, in specialized structures called Pawlowsky glands.](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2024/05/052024-ti-lice_plague_feat.jpg?fit=1030%2C580&ssl=1)
A human body louse (green in this fluorescent microscope image) has special glands in its head that can get infected with plague bacteria (red/orange).
David M. Bland (CC0)