Cysticercosis in Domestic Animals and Rodents / 中国人兽共患病学报

Cysticercus cellulosae, C. bovis, and C. taiwanensis are the three species of cysticercosis of human taeniid with their adults worms Taenia solium, T. saginata saginata and T. s. asiatica respectively. C. cellulosae is prevalent in America, Europe and Asia, C. bovis in Africa, America and Asia and C. taiwanensis in Asia. The natural infection source is pig for C. cellulosae, cattle for C. bovis and pig and wild boar for C. taiwanensis. The predilection sites are muscles for C. cellulosae and C. bovis and liver for C. taiwanensis. While the prepatent periods of these three species were 60-70 days, 60-75 days and 28 days respectively. Most C. cellulosae and a few for C. bovis and C. taiwanensis survive in pig, while most C. bovis and a few for C. taiwanensis survive in cattle. In rodent, all three species have a long life. C. cellulosae and C. bovis migrate through blood and lymph vessels to the small intestinal wall and then to the body muscles while C. taiwanensis migrate through blood vessels to the small intestinal wall and then to the liver. The minimal effective dosage of praziquantel against cysticercosis should be 100 mg/kg daily for three consecutive days.

Experimental studies on small hooks preceding large hooks in the growth and development of Taenia solium metacestodes.

In the present study, we have determined the growth and development pattern of rostellar hooklets of Taenia solium cysticerci (Zhengzhou and Harbin strains) in three pigs (1 SEM and 2 L-SEM strains) 89-196 days post experimental infection. A total of 3,675 cysticerci were collected from 3 pigs, 3,007 (82%) of 3,675 cysticerci were evaginated by enzyme method. 439 (15%) evaginated cysticerci were carefully examined and measured after dehydration, staining, and mounting on microscopic slides. Among 439 cysticerci, 234 (53%) had pair rostellar hooks, 88 (20%) with unpair hooks, 60 (14%) only small (outer row) hooks, and 57 (13%) no hooks including 34 hooks were completely dropped and 23 no hooks developed. The number ranged from 10 to 17 pairs for pair hooks and 1 to 29 for unpair ones. The length and width of rostallar hooks on the scolex of cysticerci were usually larger in the pig with longer infection time. Moreover, cysticerci with pair and unpair rostellar hooks had only small hooks and no hooks were present on their scolices. However, cysticerci with only large (inner row) hooks were not found. These findings indicate that the growth and development of small hooks precedes that of the large hooks in the formation of the two-row pattern rostellar hook in Cysticercus cellulosae.

Studies on abnormality of metacestodes and adult worms of Taenia solium and Taenia saginata asiatica in rodents and pigs.

Abnormalities are not uncommon in Taenia saginata and T. solium. After examining 328 mature proglottids from 2 adult worms from two experimentally infected hamsters, 13 (4.0%) were found to have no genital pore but with numerous testes and several vas efferents; 1 (0.3%) one genital pore with one reproductive system; 12 (3.7%) one on each side with two sets of reproductive system; 17 (5.2%) two on one side with 2 sets of reproductive system; 8 (2.4%) one on one side and two on the other side with 3 sets of reproductive system; 2 (0.6%) two on each side with 4 sets of reproductive system; 4 (1.2%) three on one side with 3 sets of reproductive system, and 4 one on one side and three on the other side with 4 sets of reproductive system. Nine evaginated abnormal cysticerci of T. s. asiatica from three experimentally infected SCID mice each had two protoscoleces and a big bladder. From two experimentally infected pigs, one abnormal cysticercus was observed to have two invaginated canals each in one end. Another one had a neck-band behind the scolex and a big bladder. This paper is not only the first report of abnormality of T. solium from hamster but also the first one of abnormal cysticerci of T. s. asiatica from pigs and mice.