Lizard Mites

Introduction

Ectoparasites are a common problem in captive lizards. Mite infestation may result in a pigmented 'black' dermatitis commonly known as "black skin disease", but ticks are rare. As the mites are usually quite ubiquitous, snake mites can infest lizards and vice versa.

Hirstiella trombidiiformis is the common lizard mite, and it can be differentiated from another common mite, Ophionyssus natricis by the presence of a pointed protruberance at the caudal end of its abdomen.

Clinical Signs and Diagnosis

The ectoparasites can usually be found in the axillae and stifle skinfolds of lizards. The tissue damage created by the mite causes swelling, irritation, erythema and even secondary bacterial infection; the skin appears as raised areas of colour change on the skin, generally on the ventral abdomen and limbs. In more serious cases, mite infestation can lead to dysecdysis, anaemia and transmission of bacterial and viral agents (e.g. Aeromonas hydrophila septicaemia, haemoparasites and inclusion body disease).

Individual mites are visible on magnification. They can be seen moving on the host, sometimes in small numbers. They can also be found drowned in the affected animal's water dishes.

Treatment

The animal and its environment need to be treated as a big part of the parasite's life cycle is spent off the host.

Initially, a bath in warm water will rid the animal of some of the mites. Alternatively, a cotton bud sprayed with an insecticide (licensed for use in puppies and kittens) can be used to remove groups of mites.
Oral or subcutaneous ivermectin repeated in 2 weeks can be given; the environment should also be sprayed with ivermectin diluted in water.
Topical insecticides (e.g. Frontline) can be applied using a sponge.