Close-up
of an unmagnified flea on a human arm.
Male
Xenopsylla cheopis
(oriental rat flea) engorged with blood. This flea is the primary vector
of plague in most large plague epidemics in Asia, Africa, and South
America. Both male and female fleas can transmit the infection.
Infection
with plague bacteria can result in swollen lymph
glands called bubos. Yersinia pestis can usually be cultured
from biopsy material from infected lymph nodes.
The
plague bacteria, Yersinia pestis, is transmitted by fleas;
ulcerations of the skin can result.
Yersinia
pestis bacteria in blood smear. Note the characteristic "safety
pin" appearance.
Plague
bacteria shown in a fluorescent antibody
test.
