Flea treatments all generally talk about breaking the flea lifecycle as a way of eradicating them.  To understand what that means, it is of course necessary to understand what the flea lifecycle is.

A human’s lifecycle begins in their mother’s womb as an egg, growing to an embryo, coming out of their mother after about nine months, then going through the stages of being a baby, child, adolescent, full adult, and finally old age and death.  So if someone wanted to wipe out the human race, if they only attacked old people or full adults, even if they succeeded then a new generation would soon rise up and take over, who would in turn create their own offspring and continue on.  It is the same with fleas.  If you only kill the adults, soon the eggs they have laid will hatch so the fleas will soon be back.  If, on the other hand, you attack the eggs, then even if you did not kill the adults they would eventually die and your flea problem would be gone.  This is the principle which most flea treatments work on, although there are those which kill the adults as well in order to speed up the process and provide fast relief from the problem.

There are six stages in the flea lifecycle.  The first is egg, the second, third and fourth are larval, the fifth is pupal and the sixth, final stage is the adult flea.  At this point of course they are ready to make more eggs and so the cycle is complete.

Unlike many parasites’ eggs, the flea egg is not sticky meaning that it will usually fall off the host animal (your pet) on to the floor or carpet.  From there, it will take anything from a couple of days to a couple of weeks to hatch.  The larvae which emerge from eggs tend to be just under 6 ½ cm (or ¼”) long, are nearly transparent and eat off any organic material they find, their favourite being the faeces of adult fleas as this is basically dried blood.  Depending on how favourable the conditions are, these larval stages will last anything from five days to two and a half weeks. When they are ready, they spin a cocoon and pupate.  In the cocoon, an adult flea can come out within three days, but if the conditions are not right it can wait up to two years.  They tend to wait for warm temperatures, humidity which is high, or even the carbon dioxide on the breath or the vibrations of passing animals.  This is why even houses which have been abandoned for a long time can get an outbreak of fleas once people move in.

The flea lifecycle can therefore be as little as a couple of weeks or as much as a couple of years, which is why it is vital not just to treat your infected pet, as this will only affect the adult fleas (although it can prevent them from laying eggs, disrupting the life cycle in that way) but also to treat the environment in order to get rid of the eggs, larvae and pupae as well.