Answer to Case 300

Answer:  Pediculus humanus nits (eggs).  This case was striking in that there were a large number of nits on these strands of hair, indicating a heavy infestation.

Given the location of the nits on hair, this is most likely the head louse (P. h. capitis) rather than the body louse (P. h. humanus).  The crab louse, as some readers suggested, also lay their nits on hair, but these nits can be differentiated by their taller operculum:

Due to the very infectious nature of head lice, the other residents of the nursing facility should be examined and treated for head lice if appropriate.






And now our poem from Blaine:

To Bobbi’s lab some ID fellow did submit

Objects plucked from the head of an elderly Brit.

For the general rule of thumb

When one sees a flat operculum

Is that it’s likely a Pediculus humanus nit