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HARVEST MITES

Note for Pet Owners:

This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

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Description
The larvae of harvest mites can cause seasonal skin disease in pets - particulary during the summer and autumn months.


Cause
Harvest mites (eg neotrombicula autumnalis) live on rotting vegetation in wooded and grassy environments and they do not live on on animals. The disease attributed to harvest mites is actually caused by accidental contact with their  larvae (called "chiggers") which are laid in moist ground.  A few adult harvest mites may be found in the coat of pets and other animals after they have been wandering through vegetation during the summer, but many hundreds of larvae can be picked up from the same environment and these are most frequently found on the animals' head, feet, or the underside of the body. The larvae may or may not cause skin irritation.


Breed Occurrence
There is no specific breed predisposition, but obviously animals with access to the mites natural environment (such as areas of rough vegetation)  have a higher risk of coming into contact with the larvae than do animals that exercise in short-grassed parks or on beaches.


Signs

There may be no irritation in some cases, but in other animals the mites cause mild to severe itchiness (also called pruritus), which may lead to rubbing, biting and scratching. Scurf may form and hairloss may occur in a few patients.


Complications
Complications are unlikely, provided the parasite is treated to prevent self trauma. 


Diagnosis
The larvae are easily recognised as clusters of small red-orange-colored "dust" attached to hairs on the body. They can be confirmed by examination under a microscope.

Sometimes there are small raised areas of the skin (called papules) and these may have a crusty appearance due to dried serum 


Treatment
An ectoparasitic aerosol, spot-on,  shampoo, powder or dip can be used to get rid of the larvae. *

In patients that develop severe irritation there may be an allergic reaction to the mite larvae, in which case a corticosteroid (eg prednisolone) may be helpful to reduce the irritation.

If untreated the larvae will feed for a few days then drop off.

* Few products have been licensed specifically for use in the treatment of  harvest mite larvae, and ectoparasitic products vary in different countries - but there are a range of different products available.that the veterinary profession can recommend.


Prognosis
Good


Long term problems
None - except repeat infestation if allowed to exercise in areas in which the mite lives.

 

Updated October 2013