The different species of Brucella are genetically very similar although each has a slightly different host specificity (see below).

However, the degree of host specificity varies strongly.

Tetraphyllidean cestodes also exhibit a remarkable degree of host specificity.

It has generally been assumed that this association has low host specificity.

There is some confusion regarding the host specificity.

But it has now separated into many species due to its host specificity.

Like other mollicutes, they show a high host specificity.

When a pathogen exhibits this type of host specificity within a plant family, it is referred to as a pathotype.

This distribution regarding host specificity would not be expected.

There is evidence of host specificity and selection of particular biting sites for some species.