[The variability of the scabies mite Sarcoptes scabiei de Geer (Acariformes, Sarcoptidae) in relation to the epidemiology of scabies. 4. The variability of the mite population on a patient and its focal variability].

The authors analyze the individual variability of the agent of scabies in populations on individual patients and in foci of the disease. They define an elementary micropopulation and a focal population notions. A total of 763 females, collected from the hands of 100 patients with scabies were examined. The findings evidence that the degree of the chetoid covering joining in the mite females, assessed in grades, may be regarded as an indicator of the population status in the pathologic process. Grades II and III females predominate in the mite population on the patients during the initial period of the disease (up to a month), whereas in the course of a full-bloom process (over a month) Grades I and 0 females prevail. The attendant exo- and endogenous factors shift the grade composition of the females towards the higher grades whatever the length of the disease. A great variety of the females in focal populations evidences reinfection and continuity of the process.