Mathematical models such as the negative binomial, Poisson and Polya-Eggenberger distributions were applied to the observed data of the number of metacercariae of Paragonimus iloktsuenensis in crab hosts, Sesarma dehaani which were collected in Hadong, South Kyong-sang Do, Korea. From the above analysis, it was found that the pattern of density of metacercariae of this lungfluke among the crab hosts was well fitted to the negative binomial distribution, rather than to the Poisson or Polya-Eggenberger distribution.
