By Nancy C. Hinkle
and Dan
Rahn
University of Georgia

When cat fleas leave their cocoons, they have a week to 10 days
to find a host animal or die. So when they find one, they don’t
leave on their own. Feeding on blood, they keep on making trouble
and flea babies until they’re kicked out or killed.

And cat fleas aren’t just for cats. These common fleas get their
blood meals from people, too, and many other mammals — dogs,
raccoons, skunks, even birds. Getting room and board on so many
hosts makes them tenacious pests of both pets and their homes.

Their feeding isn’t fun for the hosts. Cat fleas’ bites itch, and
pets scratch and bite themselves repeatedly. Puppies and kittens
with lots of fleas can get anemic and even die.

Cat fleas don’t carry many diseases. But they can transmit the
agents that cause typhus and cat scratch disease. They’re
intermediate hosts for dog tapeworms, too, which can affect small
children as well as dogs and cats.

Flea allergy dermatitis

Many dogs and some cats develop flea allergy dermatitis. For
them, the bites trigger a cascade of symptoms in a misery of
excessive grooming, hair loss and bare skin with weeping sores
that often lead to secondary infections. And the best way to
treat it is to get rid of the fleas.

Cat fleas are small, dark, reddish brown, wingless insects with
bodies that are flattened side-to-side. They’re covered with
backward-pointing spines that make them hard to pull from a pet’s
coat. And their long hind legs are well adapted for jumping.

Female fleas mate and start laying eggs within two days.
Averaging one an hour, they can lay hundreds of eggs in the
several weeks they live. And when conditions are right, it takes
only a couple of weeks for the eggs to become adults.

Only adults bite

The only good news is that only adult fleas are parasitic. All
other life stages develop off the host.

The eggs, about a millimeter long, hatch in two days, or one with
ideal temperatures. The white, eyeless, legless larvae seldom
travel far, feeding on flea feces, dry blood and other things
that collect where pets live. The larvae develop in 10 days to a
month, then spin silk cocoons that look like little dirt clods or
lint balls.

In the cocoons, the larvae change into pupae and then adults in
about four days. And when the time is right — from less than a
day to more than a year — the adult breaks out in its
life-or-death search for a host.

Since they have to have blood to survive, treating host animals
is the best way to kill fleas.

Flea busters

Several products do this well. Many contain pyrethrins, which are
safe and effective but don’t provide residual control. Other
over-the-counter compounds include spot-on permethrin products,
which are limited to dogs and can be lethal to cats.

Veterinarians can prescribe products that give weeks of control
with one application. These are applied in small amounts on the
back of the pet’s neck and spread over its body in skin oils.

Other products come as sprays. These kill fleas on the pet within
a few hours and then keep working for weeks.

Once pets have been treated, it will take a while for the fleas
around them to die off. As they develop, fleas keep hopping onto
the pet, which keeps “harvesting” them from surrounding areas
until they’ve been killed.

Insect growth regulators can break the flea life cycle. These
compounds don’t kill adult fleas. But they do prevent eggs and
larvae from completing their development. So any fleas brought
into the area won’t build up a sustaining population.

Places where pets hang out gather flea eggs and larval food. So
keep these areas clean and vacuumed, and treat them to prevent
infestations and protect pets and people.