Features and Morphologic Differences Between 2 Strains of Sarcoptes Scabiei from a Norwegian Scabies Patient and a Scabietic Dog

Lee, Kyung Ho; Cho, Baik Kee

Abstract

BACKGROUND
Variability becomes evident not only if one compares the strains obtained from 2 different host species (host variability) but also within a single strain infesting an individual animal (individual variability). Third kind of variability is observed occasionally when strains from the same host are compared, but in geographically separated countries (geographical variability). However, morphological differences between 2 strains of Sarcoptes scabiei from human and canine scabies have not been studied well in Korea. OBJECTIVE: We compared morphologic differences between 2 strains of Sarcoptes scabiei from a Norwegian scabies patient and from a scabietic dog to assess their variabilities. METHODS: Twenty females and 10 deutonymphs of Sarcoptes scabiei from a Norwegian scabies patient and 27 Sarcoptes scabiei from a dog with canine scabies including 10 females, 10 deutonymphs and 7 protonymphs were collected and observed for this study. We measured and examined size of mites, number of squamous dorsal thorns, type of bare area, number and distribution of squamous ventrolateral thorns under the phase contrast and/or light microscopes. RESULTS: In Sarcoptes scabiei from the dog, squamous dorsal thorns and squamous ventrolateral thorns increased in number as they mature from protonymph to female. In Sarcoptes scabiei from the Norwegian scabies patient, however, squamous dorsal thorns increased in number as they mature and only 1-2 squamous ventrolateral thorns were found in a few females. In Sarcoptes scabiei from the dog, all females had type I bare area, but 8 deutonymphs (80%) had type I bare area and 4 protonymphs (57%) had type II bare area predominantly. In Sarcoptes scabiei from the Norwegian scabies patient, 9 females (90%) had type II bare area and 8 deutonymphs (80%) had type II bare area. In Sarcoptes scabiei from the dog, 8 of 10 females and 4 of 10 deutonymphs had more than three pairs of squamous ventrolateral thorns but 16 of 20 females and 10 of 20 deutonymphs from the Norwegian scabies patient did not have neither right nor left squamous ventrolateral thorns. The size of S. scabiei from the dog was bigger than the size of S. scabiei from the Norwegian scabies patient. CONCLUSION: We confirmed that individual variability, host variability, and geographical variability by observing the 2 strains of Sarcoptes scabiei from a Norwegian scabies patient and a scabietic dog. These results will be helpful for the basic references in morphological studies on scabies mites in Korea as well as in making the diagnosis of canine scabies in humans and dogs.