Abstract

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The ectoparasite Demodex bovis was isolated from fresh infected purulent material collected from cattle with demodecosis. The life-cycle and ultrastructure of the mite were studied using scanning electron microscope. The mite was tested for survival, motility, and type of motility in tap water, physiological saline, and ringer's solution at increasing temperatures. Furthermore, the survival time of D. bovis in 5% and 10% potassium hydroxide was investigated. The life-cycle of D. bovis passed through several developmental stages from ovum, larva, protonymph, nymph to adult male or female mites. All morphologic characteristics observed under light microscopy were confirmed in electron photomicrographs. The mite showed maximum motility at temperatures simulating the temperature of their habitat in the pilosebaceous units of their host. The longest period of survival was recorded in physiological saline and Ringer's solutions. Examination of the mite during motility testing showed that the movement of the mite was of a crawling nature rather than a fast free progressive movement. The legs of the mite moved forwards in an arc of a small radius and backwards in an arc of maximum radius. This phenomenon allowed the mite to move forwards by pushing its body to the front on the backward swing. The study added a valuable knowledge to the basic biology of D. bovis. The ultrastructure, life cycle, and other biological characteristics of Demodex species isolated from domestic animals in the Sudan should be investigated.

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