Studies on morphological characteristics of Japanese strain of Schistosoma japonicum in rabbits.

The present investigation was undertaken to determine some morphological characteristics of Japanese strain of Schistosoma japonicum, the results are summarized as follows: (1) The pattern of testes in male worms can be divided into two types: the tandem (37.6%) and non-tandem (62.4%). (2) The number of testes varied from 1 to 13. The percentage of specimens with 7 testes was much higher than of others with both in tandem (70% against 30%) and non-tandem (86% against 14%) arrangement. (3) The unusual/irregular sets of testes including 2-3 additional sets were found in 158 (or 4.5%) of 3,498 male worms. Specimens with 7 testes in the unusual/irregular location numbered the highest (69.6%); the next with 8 (14.6%) and 6 (12%); and the lowest with 5 (3.8%). (4) Forty or 2.8% of 1,417 male worms were found to have 2-4 cecal loops. The cecal union located in 71-80% of worm bodys from the anterior end of male worm was found in highest number; the next in 61-70%; and the lowest in 51-60% and 81-90%. The location of united ceca in female worms was found all in the posterior part of body. (5) The ovary in all 125 females was located in the posterior portion of worm body except in 4 specimens. (6) The number of eggs in the uterus of female worms varied from 50 to 300. The mean number was 103.