fleas and plague

flea order

siphonaptera

resilin

an elastic protein band in the flea that helps transmission; lock legs and release to jump

what do fleas use to breathe?

spiracles

what are their flat bodies prone to?

desiccation

flea lifecycle

adults feed on LIVE hosts; vibration and chemicals activate them, complete metamorphosis

what is the oriental rat flea a vector for?

bubonic plague

Yersinia pestis

gram negative bacteria that causes the bubonic plague gets stuck in the neck of the flea and starves it causing it to bite more; low bacteria rate to create enough damage for bubonic plague

three forms in human epidemics

bubonic- buboes form in lymph nodes

septicemic- spreads throughout the body

pneumonic- patients are infective via respiratory droplets

if 50% of the people died during the plague, 50% lived. what could be a reason?

the survivors had pre-existing resistance trait and survived and trait selected for the offspring to have trait

who had the groundwork for germ theory of disease

Louis Pasteur

who confirmed the germ theory?

Robert Koch

was there a social/religious stigma around the plague?

yes, the wealthy were able to leave and travel to get away from the plague and therefore believed “god bestows wealth and health on the pure and pious” implying the poor and sick deserve it