VPA 221: Veterinary Entomology and Acarology (1+1)

EFFECT ON THE HOST

Direct Effect

Flea bite dermatitis

• Flea bite allergy is common in dogs and cats
•  It is due to the sensitization of the animal to the saliva of the flea, a hapten in the saliva of the flea becomes antigenic by fusion with skin collagen and incites an immediate hypersensitive reaction followed by delayed hypersensitivity reaction
• This results in intense pruritus in the lumbosactral area, abdomen, hind legs and neck region
• Lesions vary from moist dermatitis to acathosis, hyperpigmentation, hyperkeratinisation etc
• Moist dermatitis may be further complicated by secondary bacterial infection
• In cats, small papules are seen in affected animals which is associated with pruritis which is referred to as Miliary dermatitis
• Excess grooming results in diffuse alopaecia
• The affected animal loses its condition rapidly, usually a high level of infestation is seen in animals especially cats which are already in a poor condition due to probably some debilitating diseases
• Older animals are also commonly infested with fleas
• Restlessness due to the itching and scratching results in poor body condition and poor appearance of the coat
• Since the fleas suck blood, a heavy infestation can also result in anaemia

Indirect Effect

• Intermediate host for the tapeworm of dogs- Dipylidium caninum - the eggs of the tapeworm are seen in faeces and the larval stages of the flea feeds on it
•  The infective stage of the tapeworm- the cysticercoids develops inside the flea larvae and reaches infective stage in the adult flea
• When the flea with the cysticercoid is accidentally ingested by dogs the dogs get the tapeworm infection
• Children are also prone to pick up the infection when they accidentally swallow the flea while in close contact with their pet dogs
• Also transmit a filarid worm of dogs- Dipetalonema reconditum

Click here to view the symptoms of Dog flea and Cat flea