Index of the Severity of Demodex Mite Infestation (ISMI)

Parameters:

(1) number of eggs per square cm

(2) number of larvae per square cm

(3) number of protonymphs per square cm

(4) number of deuteronymphs per square cm

(5) number of adults per square cm

(6) percent of the facial area involved (100% indicates the entire face)

ISMI =

= ((5 * (egg count)) + (4 * (larval count)) + (3 * (protonymph count)) + (2 * (deuteronymph count)) + (adult count)) * (percent of face involved) / (2 * 5)

where:

• The percent of facial area involved could be a decimal fraction or a whole number form 0 to 100. In Table 3, the mite density is given as 3 to 8 per square cm and the ISMI from 10 to 20.

• The different stages are described in Nutting (1976).