Rickettsia felis -Cat Fleas

The Cat Flea (Ctenocephalides felis) 

Fleas are common parasites of domestic and feral cats. The parasite is responsible for flea allergy and dermatitis, and is an intermediate host of Rickettsia spp, the filariid worm Dipetalonema reconditum, and the tape worm Dipylidium caninum.

Cat fleas deposit their eggs in the hair of their host. The eggs are pearly white, oval with rounded ends, and 0.5 mm long. They fall from the hair or fur and drop onto bedding, carpet, or soil, where hatching occurs in 1-6 days. Newly hatched flea larvae are 1-5 mm long, slender, white, segmented, and sparsely covered with short hairs. Larvae are free-living, feeding on organic debris found in their environment and on adult flea faeces, all of which are essential for successful development. Flea larvae avoid direct light and actively inhabit carpet fibres or under grass, branches, leaves, or soil.

Temperature and humidity is an important factor for survival of larvae. The entire life cycle of the cat flea can be completed in 2-14 days or can be prolonged for up to 350 days. Under most household conditions, cat fleas complete their life cycle in 3-6 wk. Adults will begin feeding almost immediately once they find a host. Female cat fleas can consume 13.6 µL of blood daily. After rapid transit through the flea, the excreted blood dries within minutes into reddish black fecael pellets or long tubular coils. Fleas mate after feeding, and egg production begins within 24-48 hr of females taking their first blood meal. Female cat fleas can produce up to 40-50 eggs/day during peak egg production, averaging 27 eggs/day through 50 days, and may continue to produce eggs for >100 days.

Clinical signs

Fleas are observed within the coat of infected cats. Secondary dermatitis, especially around the tail base are easily observed with the naked eye and without microscopic examination. Affected cats often show increased attention, scratching and biting around the tail area and alopecia are common secondary symptom associated with flea burdens. In poor socio-economic regions of the world, fleas are often associated with other ectoparasites such as the flea Echidnophaga gallinacea, the tick Rhipicephalus sanguineus and louse Heterodoxus spiniger.

Fleas can cause iron deficiency anaemia in heavily infested cats, particularly kittens. Cat fleas are also implicated in transmission of Rickettsia felis, a worldwide, low-grade zoonotic disease causing anaemia.

NB. Veterinary advice should be sought regarding flea treatment for cats. There are many suitable over-the-counter products aimed at flea treatment, but care needs to be taken in products that contain pyrethrin, as pyrethrin toxicity is a common problem in cats.


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