Studies on Leptospirosis in Animals in Japan
IV. Experiments on Abortion in Guinea Pigs Infectad with Leptospira
1961 Volume 35 Issue 3 Pages 209-216
Details
1961 Volume 35 Issue 3 Pages 209-216
Leptospira autumnalis, isolated from cattle, was injected to pregnant guinea pigsin oder to prove whether leptospira infection may be cause of aborion in pregnant animals or not. The results obtained were as follows.
1. Of 21 pregnant guinea pigs which were injected with leptospira, 13 abortion, 2 p premature and 6 normal deliveries were observed.
2. The age of these fetuses was presumed by the'_r body length. It was found, that all the aborted fetuses were less than 60 days of age and the premature delivery occurred at about 60th to 70th days of pregnancy. Regular parturition was observed after the complete pregnant period. Accordingly, if we used pregnant guinea pigs before about the 50th day of pregnancy, all of them would be abort.
3. Leptospira was isolated almost usually from the emulsiar mixture of kidneys and liver of dams and frequently from the uterus and placenta, while the isolation of leptospira successed only in 2 of 21 fetuses.
4. By the time when abortion, was occured the guinea pigs were classified into 4 groups: those aborted (1) at the begining of the febrile stage, (2) during the febrile stage after that, (3) after the febrile stage, and (4) later than that stage. In the first and second groups, leptospira was isolated from the kidney, uterus and placenta but not from the fetus, and in the third group, from the kidney, uterus placenta and fetus. In the fourth group it was never detected from the kidney, uterus, placenta and fetus.
5. From the results obtained, the mechanism of abortion is considered as follows. The abortion in the first group occurred mainly due to the rise of fever accompanied with leptospiremia. In the second group, abortion was caused by the fever and leptospira infection producing pathological alteration in the placenta. In the third group, death of the fetus and the degeneration of the placenta following by leptospira infection were the principal causes of abortion. In the fourth group, it seemed, that the fetus died from the above mentioned causes were delivered after longterm stay in the uterus, as semi-mummified fetus was found in some cases.
