Adult fleas live between 6-12 months and during that time, the female will lay around 300-1000 eggs in small batches of 3-18 per day and 4-8 eggs laid after each blood meal. Therefore, fleas have the potential to multiply and infest an area rapidly. The 15 day lifecycle of the flea comprises:
Egg -> larvae -> pupae -> adult flea (blood meals taken from the host such as a cat/person)
Approximately 95% of the population of an infestation will live in the environment and not on the host, eg, carpets, between floorboards, etc. The flea larvae feed on virtually any organic debris including the host’s skin cells, faeces and partly digested blood from the adult flea. They are most hardy in the pupae stage and can live in pupae form almost indefinitely if there are no hosts available upon which to feed (eg, a vacant property).
Fortunately, following the demise of the black rat in the UK, the tropical flea which lives on this rat and is responsible for the bubonic plague (the black death), is rarely found. These days, the most common flea in the home is the cat flea (Ctenocephalides felis), followed by the bird flea (Ceratophyllus gallinae). Fleas can cause significant discomfort to people because their biting can cause considerable itching which may then lead onto a secondary infection from numerous bites and intense itching.
Currently, there is minimal evidence that cat fleas vector disease, however, they are capable of transmitting Bartonela henselae which is unlikely to cause symptoms in people or cats unless they have low immunity.
Abating your flea infestation will start with a site assessment to identify the source of the problem, the species involved and an appropriate treatment plan to eradicate them and prevent reinfestation.