Difficulty in identifying carriers of animal diseases

Nature 
Difficulty in identifying carriers of animal diseases may lead to the spread of infection and to epidemics. It may arise from the fact that the carriers of the disease may not be initially recognized, or they may be immune, or the symptoms may be very slight and easily confused with those of other diseases. Difficulties in identification may also arise from the fact that a disease such as anthrax has many different vectors.
Value(s) 
Type 
(F) Fuzzy exceptional problems