Nature Bulletin No. 293-A   February 10, 1968
Forest Preserve District of Cook County
Richard B. Ogilvie, President
Roland F. Eisenbeis, Supt. of Conservation

****:FLEAS

Did you ever have fleas? We hope not. Just one of these tiny tormentors 
can cause a lot of commotion because it bites again and again, usually 2 
or 3 places in a row, especially about the legs or waist. The bites itch 
more and more, for several days. The flea is hard to find and harder to 
catch. A stray cat or dog, sleeping under your porch, may leave enough 
fleas and flea eggs to start an epidemic; or your own pet may get them 
from other animals. The Dog Flea and the Cat Flea both feed on dogs, 
cats or people.

Fleas rank next to the bees, wasps and ants at the top of the insect 
world, and are the only group of wingless insects which have four life 
stages (complete metamorphosis): egg, larva, pupa and adult. The adult 
has a flat hard-skinned body, very thin from side to side, which permits 
it to slip between the hairs of feathers of the animal on which it feeds. 
Its mouth parts are made for piercing the skin and sucking the blood of 
its host. The large hind legs enable it to jump as much as 13 inches 
horizontally and almost 8 inches high.

A female may lay several hundred eggs, a few at a time, on the animal 
or in its bedding and the dirt around it. The eggs are not glued in place, 
as is the case with lice, and usually fall off. The hairy thread-like larva, 
without legs or eyes, has chewing mouth parts and feeds on animal 
matter or filth. When full grown it forms a cocoon of white silk -- the 
pupa stage. The length of time spent in each stage depends upon the 
species, the weather and other conditions, so that 2 weeks or as much as 
2 years may elapse from the time an egg is laid until the adult emerges, 
ready to leap upon anything that passes by. Further, an unfed adult may 
remain alive a year or more. This explains the fact that one time, when 
our family returned home after being absent several months, we found 
the house alive with leaping hungry fleas.

There are at least 500 species of fleas and almost half of these are found 
in North America and the West Indies. All of them feed on warm-
blooded animals; usually on a few kinds of wild mammals or birds. 
Only a few species affect man but these are very troublesome -- even 
dangerous -- because they may shift from one host to another and some 
of them transmit diseases. The Human Flea, common in the West 
Indies, occurs in some of our western states where it is found on hogs, 
dogs, skunks, rats, mice, or deer as often as on man and in his 
dwellings. The fur-bearers and all kinds of rodents have fleas.

In the great outbreaks of bubonic plague, fleas have been the most 
important factor in the spread of this terrible disease which is fatal to 
rats, monkeys and man. At least 9 species may carry it but the worst is 
the Indian Rat Flea now found in many places in this country. The 
California Ground Squirrel Flea, which also bites rats, spread bubonic 
plague among the ground squirrels in several Pacific and mountain 
states. Rodent fleas also transmit tapeworms, typhus fever, and 
probably tularemia or rabbit fever.

The Sticktight Flea, which frequently kills young poultry and causes 
hens to quit laying eggs, also attacks dogs, cats, horses and man. This 
flea imbeds its whole head in the skin. The Chigoe Flea of the West 
Indies feeds on blood and then the female burrows into the skin of some 
animal, frequently between the toes and under toenails of people. As the 
eggs develop, her body may become as large as a pea and cause a 
serious ulcer.

David Harum said: "a reasonable amount o' fleas is good fer a dog -- 
keeps him from broodin' over bein' a dog, mebbe".