Nits
The term nit refers to either a louse egg or a louse nymph. With respect to eggs, this rather broad definition includes the following:
- Viable eggs that will eventually hatch
- Remnants of already-hatched eggs
- Nonviable eggs (dead embryo) that will never hatch
This has produced some confusion in, for example, school policy (see The "no-nit" policy) because, of the three items listed above, only eggs containing viable embryos have the potential to infest or reinfest a host. Some authors have reacted to this confusion by restricting the definition of nit to describe only a hatched or nonviable egg:
In many languages the terms used for the hatched eggs, which were obvious for all to see, have subsequently become applied to the embryonated eggs that are difficult to detect. Thus the term "nit" in English is often used for both. However, in recent years my colleagues and I have felt the need for some simple means of distinguishing between the two without laborious qualification. We have, therefore, come to reserve the term "nit" for the hatched and empty egg shell and refer to the developing embryonated egg as an "egg". —Ian F. Burgess (1995) The empty eggshell, termed a nit... —J. W. Maunder (1983) ...nits (dead eggs or empty egg cases)... —Kosta Y. Mumcuoglu and others (2006)Others have retained the broad definition while simultaneously attempting to clarify its relevance to infestation:
In the United States the term "nit" refers to any egg regardless of its viability. —Terri Lynn Meinking (1999) Because nits are simply egg casings that can contain a developing embryo or be empty shells, not all nits are infective. —L. Keoki Williams and others (2001)Note that all these quotations appear to reject the notion that louse nymphs are nits and may indicate that the nit definition is currently in flux.
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