Disease may play an important role in the decline or extinction of sma
ll, isolated animal populations. Disease also has thwarted attempts to
reintroduce some endangered captive-bred species. Despite this, the i
mpacts of disease rarely have been considered in the planning and desi
gn of reintroduction programmes. A remnant wild population could be de
cimated by a disease cointroduced with reintroduced animals. Alternati
vely, diseases that are endemic in wild animal populations could be fa
tal for those immunologically naive individuals that are reintroduced.
We contend that the planning of reintroduction programmes should incl
ude an examination of the potential impacts of disease on extant popul
ations and on animals targeted for release. A number of steps are outl
ined to reduce disease risk and to minimise the probability of failure
of reintroductions because of disease.