Department of Eco-epidemiology of Parasitic Diseases, Institute of Developmental Biology and Biomedical Sciences, Faculty of Biology, University of Warsaw, 1 Miecznikowa Str, 02-096, Warsaw, Poland.
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawińskiego Str, 02-106, Warsaw, Poland.
Parasit Vectors. 2021 Mar 2;14(1):132. doi: 10.1186/s13071-021-04638-0.
Protozoa in the genus Babesia are transmitted to humans through tick bites and cause babesiosis, a malaria-like illness. Vertical transmission of Babesia spp. has been reported in mammals; however, the exact timing and mechanisms involved are not currently known. The aims of this study were to evaluate the success of vertical transmission of B. microti in female mice infected before pregnancy (mated during the acute or chronic phases of Babesia infection) and that of pregnant mice infected during early and advanced pregnancy; to evaluate the possible influence of pregnancy on the course of parasite infections (parasitaemia); and to assess pathological changes induced by parasitic infection.
The first set of experiments involved two groups of female mice infected with B. microti before mating, and inseminated on the 7th day and after the 40th day post infection. A second set of experiments involved female mice infected with B. microti during pregnancy, on the 4th and 12th days of pregnancy. Blood smears and PCR targeting the 559 bp 18S rRNA gene fragment were used for the detection of B. microti. Pathology was assessed histologically.
Successful development of pregnancy was recorded only in females mated during the chronic phase of infection. The success of vertical transmission of B. microti in this group was 63%. No evidence of pregnancy was found in females mated during the acute phase of infection or on the 4th day of pregnancy. In the group infected on the 12th day of pregnancy, numerous complications including loss of pregnancy and stillbirths were recorded. During the acute phase of infection, parasitaemia was lower in pregnant females in comparison to infected, non-pregnant control females.
Acute B. microti infection prevents the initiation of pregnancy and embryonic development if it occurs during the first trimester, and causes severe complications in foetal BALB/c mice in the second and third trimesters of pregnancy. Chronic B. microti infection has no detrimental impact on the initiation and development of pregnancy, but results in congenital infection of the offspring. Further study is required to determine the extent to which maternal anti-babesial immune responses contribute to compromise pregnancy in the murine model of congenital Babesia infection.
巴贝西虫属原生动物通过蜱叮咬传播给人类，并导致巴贝虫病，一种类似疟疾的疾病。哺乳动物中已经报道了巴贝西虫属的垂直传播；然而，目前尚不清楚涉及的确切时间和机制。本研究的目的是评估在怀孕前感染（在巴贝西虫感染的急性或慢性阶段交配）的雌性小鼠和在怀孕早期和晚期感染的怀孕小鼠中，微小巴贝西虫的垂直传播的成功率；评估怀孕对寄生虫感染（寄生虫血症）过程的可能影响；并评估寄生虫感染引起的病理变化。
第一组实验涉及两组在交配前感染微小巴贝西虫的雌性小鼠，并在感染后第 7 天和第 40 天进行授精。第二组实验涉及在怀孕期间感染微小巴贝西虫的雌性小鼠，在怀孕第 4 天和第 12 天进行感染。使用针对 559 bp 18S rRNA 基因片段的血液涂片和 PCR 检测微小巴贝西虫。通过组织病理学评估病理学。
仅在感染慢性阶段的雌性小鼠中记录到成功妊娠。在该组中，微小巴贝西虫的垂直传播成功率为 63%。在感染急性阶段或在怀孕第 4 天交配的雌性小鼠中未发现怀孕迹象。在怀孕第 12 天感染的组中，记录到许多并发症，包括妊娠丢失和死产。在感染急性期，与感染的未怀孕对照雌性小鼠相比，怀孕雌性的寄生虫血症较低。
如果在妊娠早期发生，急性微小巴贝西虫感染会阻止妊娠的开始和胚胎发育，并导致妊娠中期和晚期胎鼠严重并发症。慢性微小巴贝西虫感染对妊娠的开始和发展没有不利影响，但会导致后代先天性感染。需要进一步研究以确定母体抗巴贝西虫免疫反应在小鼠先天性巴贝西虫感染模型中对妊娠失败的影响程度。
