Bubonic plague is primarily transmitted to humans through what type of pest?

Bubonic plague is primarily transmitted to humans through fleas, which are ectoparasitic insects that can carry the bacteria Yersinia pestis. These fleas often infest rodents, particularly rats, and when they bite an infected host, they can acquire the bacteria. When the infected flea then bites a human, it can transmit the bacteria, leading to the onset of bubonic plague.

Understanding this transmission pathway is crucial, as it highlights the role of fleas in the spread of the disease and underscores the importance of controlling flea populations in areas where plague is a concern. The other pests listed do not play a direct role in the transmission of bubonic plague to humans, which focuses specifically on the relationship between fleas and infected rodents.