Objective: To study congenital transmission of Trichinella spiralis in mice and observe the protection of anti-Trichinella antibodies from the infected dams to challenge infection.
Methods: According to the gestation (fertilization), the Kunming mice were divided into two groups: the infected group after gestation and the gestated group after infection. New-born mice were cut into small pieces to separate the larvae within 1 day after birth. One-day-old offspring born to normal dams were nursed by the infected dams, slaughtered after 21 days and examined for the larvae. Serum anti-Trichinella antibody level in offspring born to the infected dams was assayed by ELISA at different time after birth, and its immune protection against challenge infection was studied.
Results: Out of 6 offspring born to the dams infected at 7 days after fertilization, two were found to be infected. Among other female mice which were first infected with T. spiralis and then gestated, only the offspring born to the dams fertilized at 8 and 22 days after infection were found to be infected, the infection rate of offspring was 20% (2/10) and 25%(2/8) respectively. All larvae recovered from the young were non-encapsulated. The cross-fostering experiment showed that none of 30 offspring born to normal dams were found to be infected. The serum antibody positive rate in 27 offspring born to the infected dams at 1,7,24, and 40 days after birth was 100%, 100%, 77.8% and 14.8%, respectively. The worm reduction rate in the offspring 40 days after birth was 62.0% after challenge infection. The worm reduction rate in mice in which sera from the offspring born to the infected dams were passively transferred was 55.7%, there was a significant difference (P<0.01) compared to the control group.
Conclusion: A transplacental transmission of T. spiralis is revealed in mice. Anti-Trichinella antibodies from the infected dams may partially protect the young from challenge infection.